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Bow Thruster

critical 94 models total

A bow thruster is a transverse propeller in a tunnel through the hull, driven by an electric or hydraulic motor, giving the master sideways thrust for berthing without tug assistance on vessels where the tunnel's drag penalty at sea speed is an acceptable trade.

Read more — Bow Thruster explained ▾

What defines a bow thruster

A bow thruster is a propeller -- usually controllable or fixed pitch -- mounted transversely inside a tunnel that runs through the hull near the bow, producing sideways thrust for low-speed manoeuvring rather than forward propulsion. It differs from azimuth thrusters or waterjets used for dynamic positioning in that it only produces thrust across the ship's centreline, is normally used below a few knots of forward speed, and is not intended for continuous running -- most are rated for intermittent duty measured in minutes per manoeuvre rather than hours. The tunnel itself is a permanent drag penalty built into the hull, accepted for the manoeuvring benefit and, on many vessels, for reduced tug dependency in port.

Bow thruster arrangement
Vertical section through a bow thruster showing the transverse tunnel through the hull with the propeller inside it, the vertical drive shaft, the right-angle gearbox and the electric drive motor mounted above.

Main components

Tunnel

A steel tube through the hull, with a grid or bar screen at each end to keep debris out of the propeller, sized in diameter and length to keep flow losses acceptable at the design thrust.

Propeller

Fixed-pitch propellers are simpler and cheaper but only produce thrust in one rotational direction, requiring a reversible motor; controllable-pitch propellers reverse thrust by changing blade angle while the motor and propeller keep turning in one direction, giving faster response.

Drive motor

Electric motors, often with a soft starter or variable frequency drive given the high starting current, are common on smaller and mid-size vessels; hydraulic motors, fed from a central hydraulic power pack, are common where thrust demand is higher or where hydraulic power is already installed for other deck machinery.

Pitch control and clutch

On controllable-pitch units, a hydraulic pitch actuator inside the hub, controlled from the bridge, along with a clutch or coupling arrangement on hydraulically driven units.

Selection and sizing

  • Required thrust against the vessel's windage area and the manoeuvring conditions expected, such as the wind speed the vessel needs to hold position against without tugs.
  • Fixed versus controllable pitch, trading simplicity and cost against response speed and control smoothness.
  • Electric versus hydraulic drive, based on what power source is already available and the duty cycle expected.
  • Tunnel diameter and depth below the waterline, which affects both thrust efficiency and the risk of aeration -- air drawn into the tunnel in light ballast condition, which sharply cuts thrust.
  • Duty rating, meaning minutes of continuous run before a cool-down period is required, against the vessel's typical manoeuvring time in port.

Regulations and class

Class rules require bow thrusters that count toward a vessel's positioning or manoeuvring notation to meet specific reliability and redundancy standards, but a thruster fitted purely for berthing convenience typically carries lighter requirements than one relied on for dynamic positioning. Where the thruster motor draws heavily on the ship's electrical system, class checks that starting it does not disturb other essential loads on the same switchboard section. Periodic survey includes the tunnel grids, propeller condition, and seal integrity where the shaft passes through the hull, since a seal failure there is a direct path for flooding.

Typical faults

FaultCauseConsequence
Thrust noticeably weaker than ratedAeration from running with insufficient depth below the tunnel in light ballast conditionReduced manoeuvring authority exactly when the ship is lightest and most affected by wind
Propeller or grid damageDebris or ice ingested through the tunnel grid, or grounding contactVibration, reduced thrust, and in severe cases shaft or bearing damage
Seal leak at the shaft penetrationSeal wear over years of service, or damage during propeller or bearing maintenanceWater ingress into the thruster compartment, requiring urgent repair given the direct connection to the sea
Overheating on extended useRunning beyond the intermittent duty rating during a long or difficult berthing operationAutomatic thermal trip cutting thrust at an inconvenient moment, or motor winding damage if the trip is bypassed

What to look for in a supplier

  • Thrust curve at bollard condition and at the vessel's typical operating draft, not only a single rated figure.
  • Duty cycle rating stated clearly, matched against realistic port manoeuvring times for the vessel's trade.
  • Spares availability for the propeller, seals and, on hydraulic units, the pitch actuator, given that a thruster failure often strands the vessel without tug-free berthing capability.
  • Reference installations of a similar tunnel size and drive type, since thruster hydrodynamics are sensitive to tunnel proportions that do not always scale linearly.

Aeration in light ballast condition is a hull design and loading issue, not a thruster fault -- before condemning the unit, check the draft and trim against the maker's minimum submersion depth for full-rated thrust.

Inspector Mode Show All 94 total

15 manufacturers · 94 models

Kongsberg Maritime

30
Brunvoll FU-45
· 250.0 kW · Tunnel thruster
Series
FU
Power (kW)
250
Tunnel diameter (mm)
1200
Type
tunnel
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Strengths
  • Compact 1.2 m tunnel fits medium‑size hulls without major structural modifications
  • Proven Kongsberg hydraulic drive offers high reliability and straightforward field maintenance
  • Good thrust‑to‑power ratio for vessels up to ~30 000 dwt, aiding port entry and tight berthing
  • Standardised inspection points (propeller blades, shaft seal, bearings, hydraulics) simplify scheduled overhauls
Weaknesses
  • Maximum power of 250 kW may be insufficient for large DP‑required vessels or high‑draft ships
  • Fixed‑direction tunnel design limits manoeuvring flexibility compared with azimuth thrusters
  • Tunnel geometry can increase hull vibration and noise at higher RPMs
  • Requires dedicated hydraulic plant and regular fluid maintenance
Typical Vessels: Product tanker (up to 30 k dwt)General cargo / container feederHandymax bulk carrierOffshore supply vessel with modest DP needsCruise ship or ferry requiring bow‑side assistance
Decision Guide: Choose if: you need a cost‑effective, space‑efficient bow thruster for vessels up to ~30 k dwt that already have hydraulic power available and require only basic manoeuvring aid. Avoid if: the vessel demands high thrust (>300 kN), full 360° azimuth capability, or DP3/4 compliance where a larger tunnel or azimuth unit is required.
Use Cases: Typically installed on medium‑size merchant ships to provide lateral thrust during low‑speed docking, tight berth entry, and as auxiliary thrust for limited dynamic positioning on offshore support vessels. The unit is also used on cruise ships and ferries where hull space is at a premium.
Manufacturer Datasheet
Datasheet
Brunvoll FU-63
· 500.0 kW · hydraulic tunnel thruster
Series
FU
Power (kW)
500
Tunnel diameter (mm)
1600
Type
tunnel
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Strengths
  • High power density (500 kW) in a compact tunnel form factor
  • Proven Kongsberg reliability and global service network
  • Robust double‑gear hydraulic drive with built‑in redundancy
  • Standardised 1.6 m tunnel fits common hull designs without major structural modifications
  • Compatible with existing ship automation systems via Kongsberg’s control suite
Weaknesses
  • Fixed‑direction thrust; no 360° azimuth capability
  • Hydraulic system requires regular oil maintenance and leak monitoring
  • Large tunnel opening may reduce hull strength if not properly reinforced
  • Installation weight can be significant for smaller vessels
  • Lower overall efficiency compared with newer permanent‑magnet electric thrusters
Typical Vessels: Container shipBulk carrierTanker (product/chemical)Cruise linerOffshore supply vessel
Decision Guide: Choose if you need a high‑thrust, proven bow thruster that integrates with hydraulic plant and can be installed in vessels with existing tunnel space. Avoid if you require full azimuth steering, want the highest energy efficiency, or wish to minimise hydraulic maintenance.
Use Cases: The FU-63 is commonly fitted on medium‑size merchant ships for port entry/exit maneuvers, tight‑berth positioning, and as auxiliary thrust for dynamic positioning on offshore support vessels. It also serves as a bollard‑pull assist on tankers and cruise ships during docking.
Manufacturer Datasheet
Datasheet
Brunvoll FU-74
· 750.0 kW · Tunnel thruster
Series
FU
Power (kW)
750
Tunnel diameter (mm)
1850
Type
tunnel
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Strengths
  • 750 kW rating delivers high bollard‑pull capability for vessels up to ~300 m LOA
  • Large 1.85 m tunnel provides efficient water flow and higher thrust per kW
  • Proven Kongsberg design with extensive field service history
  • Hydraulic drive offers rapid response and fine speed control
Weaknesses
  • Relatively large tunnel cross‑section limits installation to ships with sufficient hull volume
  • Hydraulic system adds complexity, requiring regular oil monitoring and filter changes
  • Higher power consumption compared with newer electric‑drive thrusters of similar size
  • Maintenance access can be challenging on deep‑installed units
Typical Vessels: Crude Oil TankerProduct TankerContainer ShipBulk CarrierLNG/LPG CarrierCruise Ship
Certifications: DNV
Decision Guide: Choose if you need a robust, high‑thrust bow thruster for large vessels and have sufficient hull space for a 1.85 m tunnel; the hydraulic drive is ideal where fast thrust modulation is required. Avoid if vessel size or hull form restricts tunnel installation, or if an electric azimuth thruster with 360° swing is preferred for DP operations.
Use Cases: Installed on large tankers and container ships to aid port entry/exit, provide auxiliary bollard‑pull during mooring, support dynamic positioning when combined with other thrusters, and improve maneuverability in confined waterways.
Manufacturer Datasheet
Datasheet
Brunvoll FU-80
· 1000.0 kW · ducted tunnel bow thruster
Series
FU
Power (kW)
1000
Tunnel diameter (mm)
2000
Type
tunnel
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Strengths
  • Very high static thrust (≈200 kN) for a single unit, enabling rapid docking and undocking of large ships.
  • Large 2 m tunnel diameter reduces cavitation and improves propulsive efficiency at low speeds.
  • Proven Kongsberg hydraulic drive system with built‑in monitoring and fault diagnostics.
  • Robust construction suitable for harsh offshore or ice‑class environments when equipped with Arctic‑thruster options.
Weaknesses
  • Large physical envelope requires significant hull penetration and internal space.
  • Heavier than comparable azimuth thrusters, affecting overall vessel weight distribution.
  • Hydraulic drive adds maintenance complexity (oil handling, seal wear) compared with electric drives.
  • Limited steering angle (fixed tunnel orientation) – cannot provide 360° thrust like an azimuth unit.
Typical Vessels: Container shipCruise linerLarge tankerLNG carrierOffshore supply vessel
Decision Guide: Choose the FU‑80 when a vessel needs maximum bow thrust for low‑speed manoeuvring, has sufficient hull space for a 2 m tunnel, and prefers the reliability of Kongsberg’s hydraulic system. Avoid it on ships where space is limited, weight must be minimised, or 360° thrust capability is required (e.g., dynamic positioning vessels that rely on azimuth thrusters).
Use Cases: The FU‑80 is typically installed on large ocean‑going vessels to provide powerful bow assistance during port entry/exit, emergency stop manoeuvres, and limited DP operations where a single high‑thrust unit can hold the ship against wind or current. It is also selected for ice‑class ships when fitted with Arctic‑thruster adaptations.
Manufacturer Datasheet
Datasheet
Brunvoll FU-100
· 1500.0 kW · tunnel thruster
Series
FU
Power (kW)
1500
Tunnel diameter (mm)
2500
Type
tunnel
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Strengths
  • Very high installed power (≈1.5 MW) enables thrust up to ~200 kN, improving low‑speed maneuverability of large ships.
  • Large tunnel diameter (2.5 m) provides efficient water flow and reduced cavitation compared with smaller units.
  • Proven Kongsberg design with integrated hydraulic control system and standardised bearing/seal packages for reliability.
  • Compatible with major classification societies’ approval programmes, facilitating class documentation.
  • Modular installation – can be fitted as a retractable or fixed unit depending on hull layout.
Weaknesses
  • Large physical envelope requires significant hull space; not suitable for vessels with limited bow volume.
  • High hydraulic power demand increases auxiliary plant load and may require dedicated pumps and cooling.
  • Maintenance intensive: regular inspection of propeller blades, shaft seals and bearing play is mandatory.
  • Weight and structural reinforcement needs are higher than for smaller thrusters, impacting design cost.
  • Less flexible than azimuth‑type units for 360° thrust vectoring.
Typical Vessels: VLCC / ULCCLNG carrierLarge container ship (>10 000 TEU)Cruise shipOffshore support vessel (FPSO, supply vessel)
Certifications: DNVABS
Decision Guide: Choose the FU‑100 when a vessel needs very high bow thrust for safe port entry, DP assistance or ice‑class maneuvering and has sufficient hull space for a 2.5 m tunnel. Avoid it on smaller ships, vessels with tight bow geometry, or when a 360° azimuth thruster would provide better manoeuvring flexibility.
Use Cases: The FU‑100 is typically installed on ultra‑large crude carriers, LNG carriers and large cruise ships to meet stringent maneuvering requirements in confined ports, assist dynamic positioning systems during offshore operations, and provide extra thrust for ice‑strengthened vessels navigating polar routes.
Manufacturer Datasheet
Datasheet
Brunvoll FU-115
· 2000.0 kW · tunnel thruster
Series
FU
Power (kW)
2000
Tunnel diameter (mm)
2800
Type
tunnel
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Strengths
  • High power (2000 kW) in a relatively compact tunnel package
  • Proven Kongsberg reliability and extensive service network
  • Integrated double‑gear hydraulic drive for smooth thrust control
  • High thrust‑to‑power ratio (~230 kN) suitable for DP‑assisted vessels
  • Available with constant‑pitch or fixed‑pitch propellers to match operational needs
Weaknesses
  • Large duct size limits installation on smaller hulls or retrofit projects
  • Heavy overall weight and high power demand on ship's electrical/hydraulic plant
  • Hydraulic system adds maintenance complexity compared to electric PM thrusters
  • Initial capital cost is higher than lower‑power tunnel models
  • Spare‑part logistics can be challenging for vessels operating in remote regions
Typical Vessels: Cruise shipLNG carrierContainer vessel (>8,000 TEU)Offshore supply vesselRo‑Ro ferry
Certifications: DNV
Decision Guide: Choose if: you need a high‑power bow thruster for vessels >150 m LOA that require strong low‑speed manoeuvring or DP capability, and the hull can accommodate a 2.8 m tunnel. Avoid if: vessel size or weight constraints prevent installation of a large duct, or you prefer an all‑electric solution with lower maintenance overhead.
Use Cases: The FU-115 is typically installed on large passenger liners, LNG carriers and high‑capacity container ships to provide rapid bow thrust during port entry, tight berthing, and dynamic positioning operations. It is also used on offshore support vessels that need strong lateral forces for station‑keeping in harsh sea states.
Manufacturer Datasheet
Datasheet
Brunvoll AR-63
· 500.0 kW · azimuth retractable thruster
Series
AR
Power (kW)
500
Tunnel diameter (mm)
1600
Type
azimuth_retractable
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Strengths
  • Retractable design reduces hull resistance when the thruster is not in use, improving fuel efficiency.
  • Full 360° rotation gives superior low‑speed maneuverability and DP performance compared with fixed‑pitch tunnel thrusters of similar power.
  • Compact 1.6 m tunnel diameter fits into vessels with limited bow space while still delivering high thrust for a 500 kW unit.
  • Kongsberg’s proven hydraulic control system offers reliable response and easy integration with existing ship automation.
  • Standardised mounting (UL/ULE) simplifies installation on new builds and retrofits.
Weaknesses
  • Retractable mechanism adds mechanical complexity, leading to higher maintenance intervals and potential for wear in the lift gear.
  • Requires a dedicated hydraulic power unit, increasing system weight and initial cost compared with electric‑drive thrusters.
  • Spare‑part availability can be longer for the retractable components than for conventional fixed tunnel units.
  • Installation tolerances are tight; improper alignment may cause premature bearing wear or vibration.
  • Not optimised for extreme ice conditions – a dedicated Arctic (ARC) version would be required for heavy ice navigation.
Typical Vessels: Offshore Supply VesselPlatform Supply VesselAnchor Handling Tug SupplyDP‑equipped product tankerMedium‑size container feeder
Decision Guide: Choose the AR‑63 when a vessel needs high manoeuvrability, DP capability and wants to minimise drag during transit by retracting the thruster. Avoid it on low‑budget projects or ships that operate primarily in ice where a dedicated Arctic thruster is required.
Use Cases: The AR‑63 is commonly installed on offshore support vessels operating near platforms, where precise positioning under wind and current is critical. It is also used on medium‑size tankers and container feeders for tight port entries and to assist with berthing in confined waterways.
Manufacturer Datasheet
Datasheet
Brunvoll AR-80
· 1000.0 kW · retractable azimuth thruster
Series
AR
Power (kW)
1000
Tunnel diameter (mm)
2000
Type
azimuth_retractable
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Strengths
  • High installed power (≈1 MW) enables strong bollard pull and rapid positioning.
  • Retractable design reduces hull resistance when the thruster is not in use, improving fuel efficiency.
  • Full 360° rotation gives excellent manoeuvrability for dynamic positioning and docking.
  • Large tunnel diameter (2000 mm) allows a big propeller for high thrust with lower blade loading.
  • Kongsberg’s integrated control system simplifies DP integration and operator training.
Weaknesses
  • Significant space requirement in the hull structure to accommodate the 2 m tunnel and retraction mechanism.
  • Higher initial capital cost compared with fixed tunnel thrusters of similar power.
  • Complex hydraulic/electrical interfaces increase installation and maintenance effort.
  • Maintenance critical points (propeller blades, shaft seals, hydraulic fluid) demand strict inspection regimes.
  • Weight and structural reinforcement may affect payload capacity on smaller vessels.
Typical Vessels: Offshore supply vesselAnchor handling tug supply (AHTS)Dynamic positioning platformLarge container shipCruise liner
Decision Guide: Choose if: you need high thrust for DP or tight‑dock manoeuvring, want the fuel‑saving benefit of a retractable unit, and have sufficient hull space for a large tunnel. Avoid if: vessel size limits installation space, budget constraints preclude higher upfront cost, or operational profile rarely requires high‑power bow assistance.
Use Cases: The AR‑80 is commonly installed on offshore support vessels that perform frequent DP operations, anchor handling tasks, and tight harbour entries where rapid lateral thrust is essential. It is also fitted on large cruise ships and container carriers to aid in berthing without tug assistance.
Manufacturer Datasheet
Datasheet
Kongsberg Azimuth thrusters
· Azimuth thruster
Model Number
Contaz Azimuthing Thruster
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Strengths
  • Wide power range (≈330 kW‑6.5 MW) covering small to ultra‑large vessels
  • Full 360° rotation enables superior maneuverability and DP performance
  • Hybrid mechanical/electric drive options improve fuel efficiency
  • Retractable or swing‑up mounting preserves hull integrity when not in use
  • Ice‑class ARC variants allow operation in polar waters
Weaknesses
  • Higher initial capital cost compared with conventional tunnel thrusters
  • More complex hydraulic/electrical systems increase maintenance workload
  • Installation requires structural modifications and precise alignment
  • Spare‑part logistics can be challenging for remote or smaller shipyards
  • Noise and vibration levels are higher than fixed‑pitch tunnel units
Typical Vessels: Offshore Supply Vessel (OSV)Dynamic Positioning vessel (DP2/DP3)Cruise ShipContainer ShipLNG/LPG CarrierIcebreaker / Polar Class vessel
Decision Guide: Choose if the vessel requires high thrust for dynamic positioning, tight‑port maneuvering, or polar operation and can accommodate the higher cost and maintenance of an azimuth system. Avoid on small coastal vessels or where budget constraints favour a simple tunnel thruster.
Use Cases: Installed on DP‑equipped offshore support ships to hold position during subsea operations; fitted on cruise liners for precise docking in congested harbours; used on Arctic carriers with the ARC version to provide reliable thrust through ice without external oil‑water interfaces.
Manufacturer Datasheet
Datasheet
Kongsberg Rim Drive Azimuth Thruster (RD-AZ)
· rim‑drive azimuth thruster
Model Number
Rim Drive Azimuth Thruster
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Strengths
  • Gear‑less drive eliminates mechanical losses, giving 7‑13% higher efficiency versus conventional diesel‑electric tunnel thrusters.
  • Full 360° rotation enables precise maneuvering and dynamic positioning without additional steering gear.
  • Low vibration and noise make it suitable for passenger vessels and offshore platforms where acoustic emissions are critical.
  • Compact installation footprint frees hull space for other systems or cargo.
  • Available in a wide power range (≈330 kW‑6.5 MW) and can be supplied with hybrid electric drives.
Weaknesses
  • Higher upfront capital cost compared with traditional tunnel thrusters of similar rating.
  • More complex integration of hydraulic/electrical control systems, requiring specialised commissioning expertise.
  • Spare‑part logistics are less common; lead times for rim‑drive bearings and motor modules can be longer.
  • Maintenance access to the rim‑mounted motor and bearing assembly is more involved than for a conventional tunnel unit.
  • Performance can be sensitive to debris or marine growth on the outer rim, demanding stricter cleaning regimes.
Typical Vessels: Offshore Support Vessel (OSV)Dynamic Positioning vesselCruise shipLNG carrier (DP‑class)Container ship with high maneuverability requirement
Decision Guide: Choose if: you need maximum thrust efficiency, low acoustic signature and full 360° steering for DP or tight‑berth manoeuvring; hull space is limited and you can absorb higher capital cost. Avoid if: the vessel is small, budget‑constrained, or operates in environments where debris ingress makes rim‑drive cleaning impractical.
Use Cases: The RD‑AZ is commonly installed on offshore wind installation vessels for precise station‑keeping, on cruise ships to reduce passenger‑perceived noise during docking, and on DP‑class tankers and LNG carriers that require reliable bow thrust while maintaining a compact hull layout. Arctic variants (ARC) are used on ice‑strengthened research ships where oil‑free operation is required.
Manufacturer Datasheet
Datasheet
Kongsberg Rim Drive Tunnel Thruster (RD-TT)
· rim‑drive electric tunnel thruster
Model Number
Rim Drive Tunnel Thruster
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Strengths
  • High thrust‑to‑power ratio (200–3 700 kW for up to 229 kN thrust)
  • No external gearbox or shaft – lower mechanical losses, higher efficiency
  • Reduced vibration and acoustic signature, beneficial for DP and passenger comfort
  • Compact tunnel design allows installation in vessels with limited hull space
  • Simplified maintenance – fewer moving parts and sealed motor housing
Weaknesses
  • Higher upfront capital cost compared with conventional shaft‑driven thrusters
  • Limited to hull thicknesses that can accommodate the larger tunnel diameter (1.6–2.0 m)
  • Cooling of the rim‑drive motor can be challenging in warm water regions
  • Spare‑part availability may be less widespread than for legacy thruster families
Typical Vessels: Container shipsCruise linersLNG carriersOffshore supply & DP vesselsLarge tankers and bulk carriers requiring high maneuverability
Certifications: DNV GL class approvalIMO Type Approval for thrusters
Decision Guide: Choose if you need maximum thrust in a confined bow space, demand low vibration/noise for DP or passenger comfort, and value long‑term energy efficiency. Avoid if budget constraints dominate, the vessel’s hull cannot accommodate the required tunnel size, or retrofitting would require extensive structural modification.
Use Cases: The RD‑TT is commonly installed as a bow thruster on newbuild DP vessels, cruise ships and LNG carriers to provide precise station‑keeping during berthing, offshore operations, and ice‑class manoeuvring. It is also used on large tankers where high lateral thrust improves port entry safety.
Manufacturer Datasheet
Datasheet
Kongsberg Standard tunnel thruster
· Tunnel thruster
Model Number
Standard Tunnel Thruster
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Strengths
  • Wide power range (200–3 700 kW) covering most merchant vessel sizes
  • High thrust output (up to 229 kN) for rapid side‑way manoeuvring
  • Modular hydraulic drive with double‑gear system simplifies installation and maintenance
  • Options for constant‑pitch or fixed‑pitch propellers allow optimisation for specific duty cycles
  • Proven Kongsberg reliability and extensive global support network
Weaknesses
  • Limited to 0° azimuth; cannot provide 360° thrust like azimuth or rim‑drive thrusters
  • Propeller blades are exposed to fouling, wear and impact damage requiring regular inspection
  • Higher vibration and noise compared with newer rim‑drive designs
  • Not optimised for extreme ice conditions – Arctic Thruster line is required for Polar Class vessels
  • Hydraulic system adds complexity and potential leak points versus fully electric drives
Typical Vessels: Container shipBulk carrierCrude oil tankerProduct tankerCruise linerOffshore supply vesselRo‑Ro ferry
Certifications: DNVABSLR
Decision Guide: Choose if you need a cost‑effective, high‑thrust lateral manoeuvring solution for vessels with existing tunnel‑thruster hull openings and moderate power requirements. Avoid if the vessel requires 360° thrust vectoring, operates in heavy ice conditions, or seeks the highest possible efficiency from an all‑electric drive.
Use Cases: The Standard Tunnel Thruster is typically installed on new builds or retrofits to provide docking/undocking assistance, low‑speed port manoeuvring and limited dynamic positioning support on merchant ships that do not require full DP capability. It is common on container, bulk and tanker classes where hull space for a tunnel box is already allocated.
Manufacturer Datasheet
Datasheet
Kongsberg Power and precisionfrom a new generation of Tunnel Thrusters
· Electric tunnel thruster
Model Number
Tunnel Thruster Type Tth
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Strengths
  • High thrust output (up to 229 kN) across a wide power range (200–3 700 kW)
  • Modular design with CP and FP propeller options for tailored performance
  • Robust double‑gear hydraulic control system for reliable steering response
  • Available in permanent‑magnet version offering 7‑13% efficiency improvement over diesel‑electric units
  • Proven Kongsberg reliability and extensive global service network
Weaknesses
  • Requires significant hull penetration and structural reinforcement during installation
  • Fixed thrust direction; azimuth steering must be provided by separate gear, limiting flexibility compared with full azimuth thrusters
  • Higher capital cost than conventional diesel‑driven tunnel thrusters
  • Hydraulic system adds complexity and periodic fluid maintenance
  • Propeller blades can accumulate marine growth, requiring regular cleaning to maintain performance
Typical Vessels: Container shipBulk carrierCrude oil tankerRo‑Ro ferryOffshore supply vessel
Certifications: DNV
Decision Guide: Choose this Kongsberg tunnel thruster when you need high lateral thrust, energy‑efficient electric drive, and a proven maintenance support network on vessels that can accommodate the ducted installation. Avoid if you require full 360° azimuth capability, have severe weight or space constraints, or are limited by budget for initial capital outlay.
Use Cases: Commonly installed on large merchant ships to aid low‑speed maneuvering in ports, assist during docking and undocking, provide emergency lateral thrust in case of main propulsion loss, and support dynamic positioning when combined with other thrusters on offshore vessels.
Manufacturer Datasheet
Datasheet
Kongsberg TUNNEL THRUSTER, type TT POLAR
· Polar‑rated tunnel thruster
Model Number
Type Tt Polar
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Strengths
  • Very high static thrust (up to 229 kN) suitable for large ice‑class ships
  • Wide power range (200–3 700 kW) and interchangeable CP or FP propellers
  • Specialised seals and adaptive damping for operation in sub‑zero temperatures and ice water
  • Double‑gear hydraulic drive provides redundancy and precise control
  • Proven Kongsberg brand with extensive field service network
Weaknesses
  • Large tunnel diameter (1.6–2.0 m) requires significant hull space and structural reinforcement
  • Hydraulic system adds complexity, maintenance workload and potential leak points
  • Higher initial cost compared with electric permanent‑magnet or rim‑drive thrusters
  • Limited azimuth capability – thrust is fixed in one direction only
  • Cavitation risk at very high thrust settings if not properly matched to hull form
Typical Vessels: Ice‑class bulk carriersArctic LNG carriersPolar research and supply vesselsIcebreaker‑assisted tankersCruise ships operating in polar regions
Decision Guide: Choose if the vessel needs maximum static thrust for low‑speed manoeuvring in ice or heavy loads, has sufficient hull volume for a tunnel installation, and requires proven reliability in sub‑zero water. Avoid if you need 360° azimuth thrust, have limited hull space, or prefer lower‑maintenance electric solutions.
Use Cases: Installed on polar‑class tankers and LNG carriers to provide reliable bow thrust during port entry/exit in ice‑covered waters; used on Arctic research ships for precise positioning while drilling or conducting surveys; employed on ice‑strengthened bulk carriers to assist with bollard‑pull operations when docking at remote ports.
Manufacturer Datasheet
Datasheet
Kongsberg TUNNEL THRUSTER, type TT
· Tunnel thruster
Model Number
Type Tt
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Strengths
  • Wide power range (200 kW – 3 700 kW) covering many vessel sizes
  • High thrust output up to 229 kN for rapid lateral movement
  • Modular blade options (CP and FP) allow optimisation of efficiency and wear resistance
  • Robust double‑gear hydraulic drive with built‑in redundancy
  • Proven Kongsberg reliability and global service network
Weaknesses
  • Requires a hull penetration, reducing structural integrity compared with retractable or azimuth units
  • Fixed thrust direction; no 360° steering capability
  • Maintenance intensive – propeller blades, shaft seals and hydraulic system need regular inspection
  • Higher acoustic signature than some low‑noise azimuth designs
  • Installation cost can be significant for large‑diameter units
Typical Vessels: Container shipCruise linerTanker (oil, chemical, LNG)Bulk carrierOffshore supply vesselRo‑Ro ferry
Certifications: DNV GL class approval
Decision Guide: Choose if the vessel needs high static lateral thrust for docking or DP support and can accommodate a fixed‑direction tunnel unit; it is cost‑effective versus azimuth thrusters when 360° steering is not required. Avoid if space for hull penetration is limited, if ultra‑low noise or full 360° manoeuvrability is essential, or if the maintenance regime cannot be met.
Use Cases: Commonly installed on large merchant ships and cruise vessels to assist with port entry/exit, tight berth handling, and as a supplemental thruster for dynamic positioning systems. Also used on ice‑class ships when paired with the Arctic Thruster variant for enhanced reliability in cold environments.
Manufacturer Datasheet
Datasheet
Kongsberg Super-Silent tunnel thruster
· Low‑noise tunnel thruster
Model Number
Super Silent Tunnel Thruster
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Strengths
  • High thrust range (200–3 700 kW) covering most medium‑size vessel requirements
  • Super‑silent design reduces underwater radiated noise, beneficial for marine life and port regulations
  • Available in constant‑pitch (CP) and fixed‑pitch (FP) blades for tailored performance curves
  • Robust double‑gear hydraulic drive with built‑in redundancy enhances reliability
  • Compact tunnel layout frees deck space compared to azimuth units
Weaknesses
  • Limited 360° steering – only provides lateral thrust, not full vectoring like azimuth thrusters
  • Installation requires a hull tunnel; retrofits on existing ships can be costly and time‑consuming
  • Higher hydraulic power demand may increase auxiliary load compared with electric PM versions
  • Maintenance access to propeller blades and shaft seals is confined to the tunnel opening
Typical Vessels: Offshore supply vesselsCruise shipsFerriesContainer ships (up to 8 000 TEU)LNG carriersResearch vessels
Decision Guide: Choose if you need high lateral thrust with a proven low‑noise solution and have hull space for a tunnel installation. Avoid if full 360° maneuverability is required, or if the vessel cannot accommodate a hull tunnel without major structural modifications.
Use Cases: The Super‑Silent thruster is commonly installed on vessels that operate in noise‑restricted ports, conduct dynamic positioning for offshore work, or require precise docking assistance while minimizing acoustic impact on marine fauna.
Manufacturer Datasheet
Datasheet
Kongsberg Permanent Magnet tunnel thruster
· Permanent‑magnet electric tunnel thruster
Model Number
Tt Pm 1600
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Strengths
  • 7–13% higher overall efficiency compared with conventional diesel‑electric thrusters
  • High thrust‑to‑power ratio (229 kN at 1.6 MW) in a compact tunnel envelope
  • Reduced fuel consumption and CO₂ emissions, supporting IMO energy‑efficiency goals
  • Fewer moving parts (no brushes), resulting in lower routine maintenance intervals
  • Integrated motor design allows fast response for dynamic positioning
Weaknesses
  • Higher capital cost than traditional diesel‑electric tunnel thrusters
  • Specialised repair and spare‑part supply chain; fewer third‑party service providers
  • Permanent‑magnet motors are sensitive to seawater ingress, requiring strict sealing
  • Thermal management can be critical at continuous high‑power operation
  • Limited proven long‑term field data compared with legacy thruster families
Typical Vessels: Container ship (≥8 000 TEU)Cruise linerLNG carrierProduct tankerOffshore supply vesselDP2/DP3 dynamic positioning vessel
Certifications: DNV GL Type Approval
Decision Guide: Choose if the vessel requires high bow thrust for DP operations, tight maneuvering in ports, or a demonstrable reduction in fuel use and emissions. Avoid if project budgets cannot accommodate the higher upfront cost, or if the operator lacks access to Kongsberg‑approved service facilities.
Use Cases: Installed on new‑build DP2/DP3 vessels and retrofitted on existing ships to replace legacy diesel‑electric thrusters, providing faster response for station‑keeping, improved port turn‑around, and compliance with upcoming emission regulations.
Manufacturer Datasheet
Datasheet
Kongsberg Retractable azimuthing thruster
· Retractable azimuth thruster
Model Number
Retractable Azimuthing Thruster
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Strengths
  • Retractable design eliminates drag during transit, improving fuel efficiency.
  • Full 360° rotation gives excellent maneuverability for DP or close‑quarter operations.
  • Available in mechanical, hybrid and fully electric drive variants for flexible integration.
  • Robust sealing and adaptive gaskets make it suitable for Arctic/ice class service.
  • Modular hydraulic double‑gear system simplifies maintenance and allows condition monitoring.
Weaknesses
  • Higher initial capital cost compared with fixed tunnel thrusters.
  • Complex installation requiring hull cut‑outs and internal housing space.
  • Moving retractable mechanism adds additional wear points that must be inspected regularly.
  • Maximum thrust is lower than a similarly sized fixed azimuth unit because of size constraints in the retracted position.
  • Requires dedicated hydraulic power pack and control system, increasing overall system footprint.
Typical Vessels: Offshore Supply VesselsDynamic Positioning vessels (DP2/DP3)Ice‑class research or support shipsCruise ships with tight hull formLNG carriers and other high‑value cargo vessels
Certifications: DNVABSLR
Decision Guide: Choose if you need a bow thruster that can be fully retracted to minimise resistance, require 360° thrust for DP or ice operations, and have sufficient hull volume for the housing. Avoid if budget is tight, hull space cannot accommodate the retractable unit, or maximum continuous bollard pull is the primary driver.
Use Cases: Commonly installed on DP‑equipped offshore vessels for precise station‑keeping, on Arctic‑class ships where ice protection of the thruster is critical, and on cruise or container ships where external thrusters would increase drag during normal sailing. Also used in retrofits where an external tunnel thruster cannot be fitted.
Manufacturer Datasheet
Datasheet
Kongsberg Azipull thruster
· Integrated permanent‑magnet tunnel thruster
Model Number
Azipull
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Strengths
  • 7–13% higher overall efficiency compared with conventional diesel‑electric thrusters
  • Compact design without a gearbox reduces weight and space requirements in the hull
  • Low acoustic signature and vibration, beneficial for passenger comfort and noise‑sensitive operations
  • High thrust output (up to 229 kN) from relatively low power ratings (1.0–1.6 MW)
  • Simplified maintenance – fewer moving parts and no oil‑filled gear train
Weaknesses
  • Higher upfront capital cost than traditional diesel‑electric tunnel thrusters
  • Limited maximum power rating (≈1.6 MW) may not suit very large vessels requiring >2 MW per thruster
  • Requires a robust shipboard electrical supply and cooling system for the permanent‑magnet motor
  • Specialised spare parts (PM motor modules) can increase lead times for repairs
  • Retrofitting on existing hulls may be constrained by shaft alignment and tunnel geometry
Typical Vessels: LNG carrierCruise shipOffshore supply vesselDynamic positioning (DP2/DP3) vesselHigh‑speed ferry
Decision Guide: Choose if you need a high‑efficiency, low‑noise electric bow thruster for DP or tight‑port maneuvering and have the electrical infrastructure to support it. Avoid if budget constraints dominate, power requirements exceed ~1.6 MW per unit, or retrofitting space is limited.
Use Cases: The Azipull is commonly installed on new builds requiring dynamic positioning, such as offshore platform supply ships, LNG carriers with strict emission limits, and cruise liners that benefit from reduced vibration and noise during docking maneuvers.
Manufacturer Datasheet
Datasheet
Kongsberg Arctic Thruster
· high‑power azimuth thruster
Model Number
Arctic Thruster
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Strengths
  • Power range from 3 MW to >10 MW enables very high bollard pull for heavy vessels
  • Oil‑free design eliminates oil‑water interfaces, meeting strict environmental regulations in polar regions
  • Adaptive sealing system tolerates temperature swings and ice ingress, reducing downtime
  • Polar‑Class‑2 / Icebreaker‑7 rating allows operation in thick first‑year ice without loss of performance
  • 360° swivel provides excellent maneuverability for dynamic positioning and tight docking
Weaknesses
  • Large physical envelope and high weight require substantial hull integration space
  • Higher capital cost compared with conventional tunnel thrusters of similar thrust
  • Complex hydraulic and control systems increase maintenance skill requirements
  • Spare‑part lead times can be long for the highest‑power variants
  • Noise and vibration levels are higher than low‑speed permanent‑magnet alternatives
Typical Vessels: IcebreakerArctic research vesselLNG carrier (polar routes)Offshore support vessel (FPSO, supply ship) operating in high latitudesHeavy lift / RoRo vessels requiring high maneuverability in icy ports
Decision Guide: Choose if: the vessel must operate in polar or heavy‑ice environments, requires >3 MW of thrust for DP or towing, and must comply with oil‑free environmental standards. Avoid if: the ship operates only in temperate waters, space and budget constraints preclude a large azimuth unit, or a lower‑power tunnel thruster meets the maneuverability needs.
Use Cases: The ARC is typically installed on ice‑class vessels that need precise low‑speed control for dynamic positioning while breaking ice, such as Arctic research ships conducting scientific surveys, LNG carriers navigating the Northern Sea Route, and icebreakers providing escort services. It also serves offshore support ships that must maintain position near polar platforms under harsh conditions.
Manufacturer Datasheet
Datasheet
Kongsberg US TYPE AZIMUTHING THRUSTER
· Azimuthing electric/hybrid propulsion
Model Number
Us Azimuthing Thruster
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Strengths
  • Wide power range (330‑6 500 kW) covering small vessels to large offshore ships
  • High thrust density – up to 229 kN from a compact pod
  • Full 360° swivel enables excellent low‑speed maneuverability and DP capability
  • Modular design with options for permanent‑magnet motors (7‑13% efficiency gain) and Arctic‑class variants
  • Integrated hydraulic control system with double‑gear set for redundancy
Weaknesses
  • Complex hydraulic/electrical integration increases installation time and cost
  • Maintenance requires specialised inspection of propeller blades, shaft seals and bearings
  • Higher capital expense compared with conventional tunnel thrusters of similar power
  • Space requirements in the hull may limit retro‑fit on older vessels
  • Noise and vibration can be higher than fixed‑pitch tunnel units if not properly tuned
Typical Vessels: Offshore Support Vessels (OSV)Dynamic Positioning vesselsCruise shipsContainer ships with DP requirementsIce‑class bulk carriers and research vessels
Certifications: DNVABSUSCG Type Approval
Decision Guide: Choose if: you need precise low‑speed thrust for DP, tight port manoeuvring or ice navigation and can accommodate the higher upfront cost and space. Avoid if: vessel size is limited, budget constraints preclude a high‑tech azimuth pod, or a simple tunnel thruster meets the maneuverability requirements.
Use Cases: The US Type Azimuthing Thruster is commonly installed on offshore supply ships for station‑keeping beside rigs, on cruise liners for rapid docking and undocking, and on ice‑strengthened vessels operating in polar waters where 360° thrust and robust sealing are essential.
Manufacturer Datasheet
Datasheet
Kongsberg Underwater mountable azimuthing thruster
· Underwater-mountable azimuth thruster
Model Number
Underwater Mountable Azimuthing Thruster
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Strengths
  • Can be fitted underwater without needing a pre‑drilled tunnel, enabling retrofit projects.
  • Full 360° swivel gives superior manoeuvrability and DP performance.
  • Broad power range (≈330 kW to 6.5 MW) covers many vessel sizes.
  • Permanent‑magnet version (UUC‑PM) offers up to 13% efficiency gain over conventional diesel‑electric drives.
  • Arctic variant provides sealed, oil‑free operation for ice‑class vessels.
Weaknesses
  • Complex hydraulic/electrical integration compared with simple tunnel thrusters.
  • Higher installation and life‑cycle cost due to specialised mounting hardware and control systems.
  • Maintenance access is more demanding because the unit is located beneath the hull.
  • Spare‑part logistics can be challenging for remote or low‑volume operators.
  • Requires detailed engineering verification for structural loads on the hull.
Typical Vessels: Offshore supply vesselsDynamic positioning (DP2/DP3) shipsLNG carriersCruise linersIcebreakers and Polar Class vessels
Certifications: DNVGL ClassificationABS ApprovalIMO Type Approval
Decision Guide: Choose this thruster when you need high thrust, full 360° steering, or a retrofit solution that avoids hull‑penetrating tunnels – especially for DP‑required or ice‑class vessels. Avoid if budget constraints favour simpler tunnel thrusters, space is extremely limited, or the vessel operates in regions with poor support for specialised hydraulic/electrical systems.
Use Cases: The unit is commonly deployed on offshore support ships that must hold position beside rigs, on large tankers and container ships needing precise port entry, and on polar vessels where sealed Arctic versions protect against ice ingress. It also serves as a retrofit option for older ships seeking enhanced manoeuvrability without major hull modifications.
Manufacturer Datasheet
Datasheet
Kongsberg Thrusters
· Tunnel thruster
Model Number
Thrusters
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Strengths
  • High thrust capability up to 229 kN in a compact tunnel layout.
  • Modular double‑gear hydraulic system offers redundancy and straightforward maintenance.
  • Permanent‑magnet variants (TT-PM) deliver 7–13 % higher efficiency versus diesel‑electric drives.
  • Integrated condition‑monitoring (vibration, pressure, seal status) compatible with ship automation systems.
  • Proven performance in harsh environments, including Arctic‑class (ARC) versions.
Weaknesses
  • Requires significant hull penetration and internal volume, limiting fit on smaller vessels.
  • Hydraulic system adds complexity and demands regular oil quality and filter changes.
  • Higher capital cost compared with basic diesel‑driven thrusters.
  • Seal and propeller‑shaft maintenance can be labour‑intensive, especially in ice conditions.
  • Potential noise and vibration that may need mitigation on passenger vessels.
Typical Vessels: Container shipBulk carrierTankerCruise linerOffshore supply vesselLNG carrierIcebreakerFerry
Certifications: DNV GLABSLR
Decision Guide: Choose if the vessel needs high lateral thrust for dynamic positioning, tight docking maneuvers, or operation in ice‑prone waters and can accommodate the required hull space. Avoid if budget constraints are primary, the ship has limited internal volume, or low‑noise requirements outweigh the performance benefits.
Use Cases: Kongsberg bow thrusters are commonly installed on large container ships for dynamic positioning during port entry, offshore supply vessels for DP operations, cruise liners to aid in precise berthing, and ice‑class vessels where the Arctic Thruster (ARC) variant provides reliable thrust in freezing conditions.
Manufacturer Datasheet
Datasheet
Kongsberg Swing-up azimuthing thruster
· Retractable azimuth thruster
Model Number
Swing Up Tcnsc Azimuthing Thruster
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Strengths
  • Full 360° rotation gives superior low‑speed handling and DP capability.
  • Swing‑up mechanism allows the unit to be retracted, reducing hydrodynamic resistance and protecting it in ice or during high‑speed transit.
  • High thrust‑to‑power ratio (up to ~229 kN at 1.6–2.0 m propeller diameter).
  • Modular design supports diesel‑electric, hybrid or permanent‑magnet motor options.
  • Available in Arctic‑class variants with ice‑compatible seals and no oil‑water interfaces.
Weaknesses
  • Complex hydraulic control system increases installation and maintenance effort.
  • Higher capital cost compared with conventional fixed tunnel thrusters.
  • Requires dedicated hull space for the swing‑up housing and sealing arrangements.
  • Seal and bearing wear are critical items; periodic overhauls are mandatory (typically every 5 years).
  • Potential for hydraulic leaks if inspection intervals are missed.
Typical Vessels: Offshore support vessels (DP2/DP3)Cruise shipsContainer shipsLNG carriersIce‑class research or supply vessels
Certifications: DNV
Decision Guide: Choose if the vessel needs high maneuverability, dynamic positioning, or operates in ice/needs reduced drag at cruise speed. Avoid if budget is tight, hull space for a swing‑up unit is unavailable, or a simpler fixed tunnel thruster meets operational requirements.
Use Cases: Commonly installed on DP‑equipped offshore supply vessels for precise station keeping, on cruise liners to aid port entry and reduce resistance when cruising, and on ice‑strengthened ships where the thruster can be retracted during ice navigation. The unit also serves as a bow‑thruster on large container or tanker conversions that require both high thrust and the ability to hide the thruster in the hull.
Manufacturer Datasheet
Datasheet
Kongsberg Propulsion, thruster and steering bridge control
· Hydraulic bow‑thruster bridge control
Model Number
Propulsion Thruster And Steering Bridge Control
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Strengths
  • Unified interface on the bridge reduces crew workload and improves manoeuvring precision.
  • Supports both constant‑pitch (CP) and fixed‑pitch (FP) tunnel thrusters up to 229 kN thrust, covering a wide power range (200–3 700 kW).
  • Built‑in diagnostics for propeller shaft seals, hydraulic pressure and bearing play simplify condition‑based maintenance.
  • Modular design allows retrofit of Arctic Thruster (ARC) or Permanent Magnet (PM) variants without changing the control hardware.
  • Class‑approved (DNVGL, ABS, LR) for DP‑2 applications on offshore support vessels.
Weaknesses
  • Hydraulic system adds weight and requires regular oil sampling, filtration and leak monitoring.
  • Higher initial capital cost compared with simple electric bow‑thruster drives.
  • Spare‑part logistics can be lengthy for specific seal kits and double‑gear hydraulic modules.
  • Complexity of the control software may need vendor‑specific training for bridge officers.
  • Performance degrades if hydraulic fluid contamination is not tightly controlled.
Typical Vessels: Offshore supply vesselLNG carrierCruise shipIce‑class bulk carrierDynamic positioning platform
Certifications: DNVGL – Class approved thruster control systemABS – Approved for DP‑2 operationLR – Lloyd’s Register type approval
Decision Guide: Choose if the vessel requires high‑thrust bow manoeuvring, integrated bridge monitoring and DP capability, especially in harsh or ice‑prone waters. Avoid if budget constraints favour a simpler electric thruster system or if the ship operates only in calm, unrestricted ports where a lower‑power solution suffices.
Use Cases: The Kongsberg bridge control is commonly installed on offshore support ships that need precise station‑keeping while loading/offloading rigs, on LNG carriers navigating tight terminals, and on ice‑strengthened bulk carriers operating in polar regions where rapid lateral thrust and real‑time monitoring are critical for safety.
Manufacturer Datasheet
Datasheet
Kongsberg Azipull Carbon Thruster
· Integrated permanent‑magnet azimuth thruster
Model Number
Azipull Carbon Thruster
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Strengths
  • High thrust‑to‑power ratio thanks to permanent‑magnet motor integration
  • 7‑13% fuel‑efficiency improvement over traditional diesel‑electric thrusters
  • Compact, low‑profile design reduces hull penetration and frees internal space
  • Reduced mechanical complexity (no gearbox) lowers maintenance intervals
  • Full 360° azimuth swing enables precise maneuvering and DP performance
Weaknesses
  • Higher upfront capital cost compared with conventional tunnel thrusters
  • Limited to the power envelope of the PM motor family (≈1 000–1 600 kW per unit)
  • Requires specialized control electronics and trained personnel for commissioning
  • Thermal management can be critical in extreme cold or hot environments
  • Spare parts inventory is less common than for legacy diesel‑driven units
Typical Vessels: Offshore supply vessels (DP2/DP3)LNG carriers and other gas tankersCruise shipsContainer ships with high maneuverability requirementsIce‑class research or support vessels (when paired with Arctic‑Thruster line)
Certifications: DNV GL Type ApprovalABS Classification
Decision Guide: Choose if you need maximum thrust efficiency, compact installation space and superior DP performance for medium‑size to large vessels. Avoid if budget constraints dominate, the required power exceeds ~1.6 MW per unit, or the operator lacks experience with permanent‑magnet propulsion control systems.
Use Cases: The Azipull Carbon Thruster is commonly installed on offshore support ships that require precise station‑keeping in harsh seas, large tankers needing rapid bow‑side maneuvering in congested ports, and cruise vessels seeking lower emissions while maintaining tight docking tolerances. It is also selected for ice‑reinforced hulls where reduced mechanical wear is advantageous.
Manufacturer Datasheet
Datasheet
Kongsberg Rim Drive Azimuth Thruster
· rim drive azimuth thruster
Model Number
Rim Drive Azimuth Thruster
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Strengths
  • No hull-penetrating shaft tunnel – reduces resistance, noise and risk of water ingress
  • High thrust‑to‑power ratio (up to ~229 kN at 1.6 MW) with up to 13% efficiency gain over conventional diesel‑electric units
  • Full 360° swivel provides excellent maneuverability for dynamic positioning and tight berthing
  • Compact installation footprint, ideal for vessels with limited hull space or low draft bow thruster rooms
  • Modular design allows easier replacement of motor or propeller without major hull work
Weaknesses
  • Higher upfront capital cost compared with conventional tunnel‑type thrusters
  • Specialised sealing and water‑lubricated bearing systems require vendor‑specific maintenance expertise
  • Limited long‑term field data for the largest power ratings (above 3 MW) on commercial fleets
  • Integration of high‑power electric drives may demand upgraded shipboard power distribution and cooling
  • Spare parts inventory is less common than for standard shaft‑driven azimuth units
Typical Vessels: Offshore Support Vessel (OSV)Dynamic Positioning vessel (DP2/DP3)Cruise shipFerryLNG carrier with high maneuverability requirements
Certifications: DNV GL Class approvalABS classification approval
Decision Guide: Choose if: you need maximum manoeuvrability, low acoustic signature and a compact bow thruster solution for DP or tight‑berth operations, and the vessel can accommodate the higher electrical power infrastructure. Avoid if: budget constraints dominate, the operator lacks experience with rim‑drive maintenance, or the ship class requires proven long‑term reliability data beyond current field experience.
Use Cases: The RD‑AZ is typically installed on offshore supply ships and DP‑class vessels where precise station‑keeping is critical, as well as on cruise liners and ferries that benefit from reduced vibration and noise in passenger areas. It is also favoured for new builds aiming to minimise hull penetrations and improve overall hydrodynamic efficiency.
Manufacturer Datasheet
Datasheet
Kongsberg Swing Up Tcnsc Azimuthing Thruster
· Retractable azimuth thruster
Model Number
Swing Up Tcnsc Azimuthing Thruster
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Strengths
  • Full 360° thrust for superior maneuverability and DP capability
  • Swing‑up design eliminates tunnel resistance, improving fuel efficiency during transit
  • High power range (330 kW – 6.5 MW) accommodates a wide variety of vessel sizes
  • Modular options including mechanical, hybrid and permanent‑magnet drives for efficiency gains
  • Arctic‑ready variants with adaptive seals for ice class vessels
Weaknesses
  • Complex swing‑up mechanism increases installation and maintenance effort
  • Higher initial capital cost compared with conventional fixed tunnel thrusters
  • Requires dedicated hydraulic power unit and associated leak‑monitoring systems
  • Limited propeller diameter relative to fixed tunnel thrusters can reduce maximum thrust at low speeds
  • Space inside hull must accommodate the retracted housing, affecting internal layout
Typical Vessels: Offshore supply vesselsDP‑class platform support shipsIce‑strengthened cargo carriersCruise ships and ferries with tight docking requirementsLNG carriers and other high‑value cargo vessels
Certifications: DNV
Decision Guide: Choose if you need maximum maneuverability in confined ports or DP operations while wanting to minimise hull resistance during cruising. Avoid if budget constraints favour simpler tunnel thrusters, or if vessel design cannot accommodate the internal retraction housing.
Use Cases: Commonly installed on offshore support vessels for dynamic positioning, ice‑class bulk carriers operating in polar regions, and cruise ships that require rapid side thrust for docking while benefiting from reduced drag when cruising. The swing‑up feature is also favoured on vessels where hull space is at a premium but high bollard pull is required.
Manufacturer Datasheet
Datasheet
Rolls-Royce / Kongsberg Maritime (UK/Norway) TT Series (Tunnel Thruster)
TT Series (Tunnel Thruster)
50-3,500 kN thrust · Seawater · Electric tunnel thruster
Type
Tunnel Bow/Stern Thruster (FP/CP)
Size Range
  • TT-1100
  • TT-1400
  • TT-1650
  • TT-1800
  • TT-2000
  • TT-2500
  • TT-3000
Power range (kW)
  • 250
  • 3500
Drive Type
Electric
Construction
FP or CP propeller, planetary gear, steel tunnel
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Service: Gear oil analysis every 1,000 hrs. Motor insulation test annually. Propeller inspection at drydock. CP hub overhaul every 20,000 hrs.
Spare Parts: Kongsberg Maritime (ehem. Rolls-Royce Marine, acquired 2019). Service: Norway, Singapore, Houston, Shanghai. Lead time: 3-6 weeks.
Strengths
  • Wide power range (250 kW – 3.5 MW) covering most merchant vessel sizes
  • High thrust output up to ~229 kN for rapid berthing and un‑berthing
  • Both Fixed Pitch (FP) and Constant Pitch (CP) propeller options allow optimisation for efficiency or thrust control
  • Robust steel tunnel construction gives long service life and good resistance to hull impacts
  • Electric drive eliminates diesel‑engine emissions in the thruster room and simplifies integration with ship‑board power management
Weaknesses
  • Provides only transverse thrust – no 360° azimuth capability, limiting manoeuvre flexibility compared with azimuth or rim‑drive units
  • Installation requires a hull cut‑through and tunnel reinforcement, increasing initial fit‑out cost and dry‑dock time
  • Propeller blades are exposed to fouling, wear and potential damage; regular inspection and occasional blade replacement are required
  • Shaft seal and bearing wear can become critical after 5–10 years of service if not monitored closely
  • Noise and vibration levels are higher than rim‑drive or podded thrusters, which may be a concern for passenger vessels
Typical Vessels: Container shipsBulk carriersTankers (crude, product, LNG)Cruise ships and ferriesOffshore supply vesselsRo‑Ro vessels
Certifications: DNV class approvalABS classificationLloyd’s Register approval
Decision Guide: Choose if the vessel needs high static bow thrust for tight port manoeuvring, prefers an electric drive for lower emissions and easier integration with DP systems, and can accommodate a hull‑penetrating tunnel. Avoid if 360° thrust vectoring is required, hull space for a tunnel is limited, or noise/vibration constraints dominate the design.
Use Cases: The TT Series is typically installed on medium to large merchant ships that operate in congested ports or require dynamic positioning assistance – e.g., container vessels entering shallow terminals, tankers docking at offshore loading facilities, cruise ships maneuvering in tight berths, and offshore supply ships performing station‑keeping near rigs.
Manufacturer Datasheet
Datasheet
Rolls-Royce / Kongsberg Maritime (UK/Norway) UL/US Series (Azimuth Thruster)
UL/US Series (Azimuth Thruster)
200-5,500 kN thrust · Seawater · Azimuth thruster (L‑drive/Z‑drive)
Type
Azimuth Thruster (L-Drive / Z-Drive)
Size Range
  • UL-305
  • US-155
  • US-205
  • US-255
  • US-305
Power range (kW)
  • 500
  • 5500
Drive Type
Electric / Diesel-Mechanical
Construction
L-drive or Z-drive, CP propeller, nozzle optional
Technical Specifications
Tunnelthrusters
Output 200–3,700 kW, propeller diameter 1,600–2,000 mm, thrust up to 229 kN, available in CP (Constant Pitch) and FP (Fixed Pitch)
Azimuth-thrusters
Leistung 330-6.500 kW (mechanical/hybrid), neun Baumgroessen, Zugkraft optimiert fuer Bollard-Pull, 360°-Schwenkung
Arctic Thruster (ARC)
Power from 3 MW to >10 MW, no oil-sea interfaces, adaptive seals, Polar-Class-2 and Icebreaker-7 to 9 MW
Permanent Magnet (PM) Thrusters
TT-PM 1000 kW (146 kN), TT-PM 1600 kW (229 kN), Effizienzsteigerung 7-13% gegenueber Diesel-Elektrik
Hydraulik-standard
Double gear hydraulics for control/ventilation/lubricant, double cylinder with pressure pipe safety, seal tank with refueling capacity
Lagerung
Rollenlager fuer Schubwelle, Schmierung mit Fett, Dichtung an Lagergehausen, Toleranz-Freispiele typisch 0,5-2,0 mm
Product Lines
  • US Azimuth Thruster
  • Arctic Thruster (ARC)
  • TCNS/C Azimuth Thruster (Swing-up/Retractable)
  • Rim Drive Azimuth Thruster (RD-AZ)
  • Tunnel Thruster Type TT/TTH
  • Permanent Magnet Tunnel Thruster (TT-PM)
  • Rim Drive Tunnel Thruster (RD-TT)
  • Underwater Mountable Azimuth Thruster (UUC/UUC-PM)
  • Retractable Azimuth Thruster (UL/ULE)
  • Azipull Thruster (Integrated PM Motor)
Common Failures & Inspection Points
  • Area: Propellerblaetter: Verschleiss, Risse, Verformung, Seewuchsbewuchs
    Check: Sichtpruefung auf Schaedigungen, Freispiel, Blattoberflaeche glatt ohne Kratzer/Dellen. Blattwurzel-O-Ringe auf Verschleiss checken, Spitzzenspiel messen. Bei Zweifeln: 1,5 bar Luftdruck auf VT-Nippel, Seifenblasen-Test auf Oellecks.
  • Area: Propellerwellen-Dichtung: Durchfeuchtuung, Oelaustrittsverlust, Verschleiss
    Check: Visual inspection for leaks around shaft seal, check sealing cavity (monitored automatically via ARC). Observe seal clip pressure (e.g. via sensor output). At 5-year overhaul: renew seal. Check adaptive pressure regulation.
  • Area: Lagerfreispiel/Lagerverschleiss: Axiales/Radiales Play ueber Norm, Bohrlochabtrag
    Check: Calipers/counter gauges: measure shaft diameter and bores (target value via manufacturer data sheet). Document caliper readings. If exceeded: replace bearing journal/bearing shells. Observe vibration/noise during operation.
  • Area: Hydraulikfluid: Verschmutzung, Feuchtigkeit, Alterung, Farb-/Geruechsveraenderung
    Check: Check fluid level in tank (target level). Color test: light/yellowish OK, cloudy/dark = change required. Particle count (if available). Change filter per manufacturer interval. Perform pressure test on hydraulic line.
  • Area: Hydraulik-Leitungen/Verbindungen: Risse, Lecks, Verformung, korrosive Belaege
    Check: Visual inspection of all hoses, pipes, connections for defects. Check for dryness, corrosion (rust spots), kink marks. High-frequency leak test if necessary. Observe operating pressure during voyage.
  • Area: Elastomer-Bauteile (O-Ringe, Dichtlippen, Gummistuecke): Hartung, Risse, Quellungserscheinungen
    Check: Visual inspection of all O-rings/seals for wear, hardening, deformation. Test with finger pressure (elasticity). Clean O-ring grooves/lubricate with gearbox oil (at 5-year overhaul). Replace damaged parts.

Type-universal inspection/service points for bow/stern thrusters (Kongsberg, Mega-Swarm 2026-06). Per-model specs not auto-populated.

Service: Lower unit oil analysis every 500 hrs. Azimuth bearing check every 5 years. Shaft seal inspection at drydock. Complete overhaul every 30,000 hrs.
Spare Parts: Kongsberg Maritime network. Lead time: 4-8 weeks for standard parts, 12-16 weeks for gear assemblies.
Strengths
  • Full 360° rotation gives superior low‑speed manoeuvrability and dynamic positioning capability
  • Modular power range (0.5–5.5 MW) fits a wide variety of vessel sizes from offshore support to ice‑class carriers
  • Optional nozzle or CP propeller increases thrust efficiency for high‑bollard‑pull applications
  • Hybrid electric or diesel‑mechanical drive options allow integration with ship‑wide power management strategies
  • Retractable (UL/ULE) and Arctic (ARC) variants provide flexibility for shallow drafts and ice operations
Weaknesses
  • High capital cost compared with conventional tunnel thrusters of similar power
  • Complex maintenance – shaft seals, hydraulic circuits and bearing inspections required at regular intervals
  • Space‑intensive installation; requires a dedicated tunnel or hull opening in the bow section
  • Propeller fouling and blade wear are critical in warm waters, demanding frequent inspection
  • Electrical‑drive versions need robust cooling and power electronics that add weight and volume
Typical Vessels: Offshore supply vessels (OSV)Dynamic positioning platform supply vesselsCruise ships and ferriesContainer ships with DP capabilityIce‑class bulk carriers and LNG carriers
Certifications: DNV class approvalABS class approvalUSCG Type ApprovalIMO Type Approval (for selected models)
Decision Guide: Choose if: the vessel requires precise low‑speed manoeuvring, DP2/3 capability, or ice‑class operation; space for a retractable unit is available; higher upfront cost can be justified by reduced port time and improved safety. Avoid if: budget constraints dominate, vessel size is below 5 MW total thruster power, or hull form cannot accommodate the required tunnel geometry.
Use Cases: The UL/US series is commonly installed on offshore support ships that need to hold position beside rigs, on cruise liners for tight port entries, and on ice‑strengthened carriers operating in polar regions where rapid thrust reversal and high bollard pull are essential. Retractable versions are favoured on shallow‑draft vessels that still demand strong bow thrust.
Manufacturer Datasheet
Datasheet

Wärtsilä

20
Wärtsilä WST Series (Steerable Thruster)
WST Series (Steerable Thruster)
200-6,000 kN thrust · Seawater · Azimuth steerable thruster
Type
Azimuth Thruster (Z-Drive / L-Drive)
Size Range
  • WST-14
  • WST-18
  • WST-24
  • WST-32
Power range (kW)
  • 500
  • 6000
Drive Type
Electric / Diesel-Electric / Diesel-Mechanical
Construction
Z-drive or L-drive gearbox, CP propeller, nozzle optional
Technical Specifications
Leistungsbereich WST
700 kW bis 4900 kW
Leistungsbereich WTT
400 kW bis 5500 kW
Leistungsbereich WST-R
750 kW bis 6500 kW
Neigungswinkel (WST-R)
8-Grad Propeller-Getriebe-Neigung für 15-20% höheren Schub
Drehbereich
360° kontinuierliche Lenkung in horizontaler Ebene
Wartungsintervalle
5-year inspections, 10-year overhauls or after 40,000–56,000 operating hours
Dichtungstechnologie
Sternguard In-Water Serviceable Seal (IWSS) - vollständig unter Wasser wartbar
Ölsystem
Integrierte Hydraulik mit Feinfiltration zur Lagerverlängerung
Product Lines
  • WST - Steerable Thrusters (700-4900 kW)
  • WTT - Transverse/Tunnel Thrusters (400-5500 kW)
  • WST-R - Retractable Steerable Thrusters (750-6500 kW)
  • WST-E - Electric Steerable Thrusters (WST-18E embedded electric)
  • Underwater-Mountable Steerable Thrusters
Common Failures & Inspection Points
  • Area: Propeller-Blätter: Erosion, Korrosion, Kantenschäden, Verschleißmuster
    Check: Perform visual inspection and NDT (non-destructive testing) according to OEM and classification society standards. Polishing in combination with edge damage repair increases operating efficiency by 2-5%. Check for pitting, erosion patterns and corrosion spots; document severe pitting areas.
  • Area: Propeller blade foot seals: wear, leakage, water ingress
    Check: 5-year overhaul: Disassemble and inspect all seals. 10-year overhaul: Complete replacement of blade foot O-rings. Check for water penetration in jet thruster assembly. Seals are critical for system protection.
  • Area: Wellendichtungen (Shaft Seals): Abnutzung, Leckage, Austauschbedarf
    Check: Measure propeller shaft wear with poker gauge (between last two stern tube seals). Perform complete inspection of tooth clearance, tooth pattern and shaft seals. 5-year overhaul: seal replacement. 10-year overhaul: comprehensive replacement.
  • Area: Bearings (Roller Bearings): wear, bearing clearance, preload, failure symptoms
    Check: 5-year overhaul: Check bearing clearance and wear. 10-year overhaul: Complete bearing replacement, reset preload, perform NDT inspection. Check main bearing axial clearance wear with feeler gauge (0.1 mm); maximum wear limit 2 mm. Use Wärtsilä bearing wear measurement system for remote monitoring of propeller shaft shoulder.
  • Area: Hydrauliksystem: Öl-Verschmutzung (Wasser, Partikel), Filtration, Ölqualität
    Check: Check gear oil regularly. At critical wear limits: partial change (bleed-and-feed) or complete oil change. Monitor water content in oil (critical >1000 ppm). Check fine filtration system and redundant filter options. Continuously filter out water ingress. Use all Wärtsilä-approved spare parts. 5-10-year overhaul: Perform oil change and filter maintenance.
  • Area: Sternguard In-Water Serviceable Seal (IWSS): seal integrity, maintenance possible underwater
    Check: Check for oil leakage at outer seal. Inspect inflatable emergency seal and inner rope guard. Fully serviceable underwater without habitat or discharge. Measure seal gap and wear. Check retrofit compatibility with other seal types. Confirm compatibility with EAL and mineral oils.

Type-universal inspection/service points for Bow/Stern Thrusters (Wärtsilä, Mega-Schwarm 2026-06). Per-model specs not auto-filled.

Service: Lower unit oil analysis every 500 hrs. Azimuth bearing inspection every 5 years. Steering system check annually. Complete overhaul at drydock.
Spare Parts: Wärtsilä global network. Lead time: 4-8 weeks standard, 12-16 weeks for gear units.
Strengths
  • Full 360° continuous steering gives superior maneuverability in confined ports.
  • Sternguard In‑Water Serviceable Seal (IWSS) allows seal replacement without dry‑docking, reducing maintenance downtime.
  • Modular power range (700 kW – 4 900 kW) fits a wide variety of vessel sizes and DP requirements.
  • Electric, diesel‑electric or diesel‑mechanical drive options enable integration with different propulsion architectures.
  • Integrated hydraulic oil filtration extends bearing life and lowers oil‑change intervals.
Weaknesses
  • Higher initial capital cost compared with conventional tunnel thrusters of similar power.
  • Complex mechanical arrangement (gearbox, bearings, seals) requires specialised spares and trained personnel.
  • Large physical envelope may limit installation on vessels with restricted hull space.
  • Noise and vibration levels can be higher than low‑speed tunnel units, requiring additional acoustic mitigation.
  • Long lead times for spare parts on older model variants (e.g., WST‑14, WST‑18).
Typical Vessels: Container shipsCrude oil and product tankersLNG carriersCruise linersOffshore supply vesselsDP2/DP3 platform support vessels
Certifications: DNV GLABSLR
Decision Guide: Choose if the vessel needs high bollard pull, DP capability or frequent port calls in tight waterways and you want to minimise dry‑dock intervals thanks to the IWSS. Avoid on small coastal vessels or when budget constraints make a conventional tunnel thruster more economical.
Use Cases: The WST series is typically installed on large ocean‑going ships that require precise docking, dynamic positioning for offshore operations, ice‑breaker assistance, and rapid emergency maneuverability in congested harbours.
Manufacturer Datasheet
Datasheet
Wärtsilä Steerable Thrusters WST
· Hydraulic steerable tunnel thruster
Model Number
Wärtsilä Steerable Thruster
Technical Specifications
Leistungsbereich WST
700 kW bis 4900 kW
Leistungsbereich WTT
400 kW bis 5500 kW
Leistungsbereich WST-R
750 kW bis 6500 kW
Neigungswinkel (WST-R)
8-Grad Propeller-Getriebe-Neigung für 15-20% höheren Schub
Drehbereich
360° kontinuierliche Lenkung in horizontaler Ebene
Wartungsintervalle
5-year inspections, 10-year overhauls or after 40,000–56,000 operating hours
Dichtungstechnologie
Sternguard In-Water Serviceable Seal (IWSS) - vollständig unter Wasser wartbar
Ölsystem
Integrierte Hydraulik mit Feinfiltration zur Lagerverlängerung
Product Lines
  • WST - Steerable Thrusters (700-4900 kW)
  • WTT - Transverse/Tunnel Thrusters (400-5500 kW)
  • WST-R - Retractable Steerable Thrusters (750-6500 kW)
  • WST-E - Electric Steerable Thrusters (WST-18E embedded electric)
  • Underwater-Mountable Steerable Thrusters
Common Failures & Inspection Points
  • Area: Propeller-Blätter: Erosion, Korrosion, Kantenschäden, Verschleißmuster
    Check: Perform visual inspection and NDT (non-destructive testing) according to OEM and classification society standards. Polishing in combination with edge damage repair increases operating efficiency by 2-5%. Check for pitting, erosion patterns and corrosion spots; document severe pitting areas.
  • Area: Propeller blade foot seals: wear, leakage, water ingress
    Check: 5-year overhaul: Disassemble and inspect all seals. 10-year overhaul: Complete replacement of blade foot O-rings. Check for water penetration in jet thruster assembly. Seals are critical for system protection.
  • Area: Wellendichtungen (Shaft Seals): Abnutzung, Leckage, Austauschbedarf
    Check: Measure propeller shaft wear with poker gauge (between last two stern tube seals). Perform complete inspection of tooth clearance, tooth pattern and shaft seals. 5-year overhaul: seal replacement. 10-year overhaul: comprehensive replacement.
  • Area: Bearings (Roller Bearings): wear, bearing clearance, preload, failure symptoms
    Check: 5-year overhaul: Check bearing clearance and wear. 10-year overhaul: Complete bearing replacement, reset preload, perform NDT inspection. Check main bearing axial clearance wear with feeler gauge (0.1 mm); maximum wear limit 2 mm. Use Wärtsilä bearing wear measurement system for remote monitoring of propeller shaft shoulder.
  • Area: Hydrauliksystem: Öl-Verschmutzung (Wasser, Partikel), Filtration, Ölqualität
    Check: Check gear oil regularly. At critical wear limits: partial change (bleed-and-feed) or complete oil change. Monitor water content in oil (critical >1000 ppm). Check fine filtration system and redundant filter options. Continuously filter out water ingress. Use all Wärtsilä-approved spare parts. 5-10-year overhaul: Perform oil change and filter maintenance.
  • Area: Sternguard In-Water Serviceable Seal (IWSS): seal integrity, maintenance possible underwater
    Check: Check for oil leakage at outer seal. Inspect inflatable emergency seal and inner rope guard. Fully serviceable underwater without habitat or discharge. Measure seal gap and wear. Check retrofit compatibility with other seal types. Confirm compatibility with EAL and mineral oils.

Type-universal inspection/service points for Bow/Stern Thrusters (Wärtsilä, Mega-Schwarm 2026-06). Per-model specs not auto-filled.

Strengths
  • Wide power range (700–4900 kW) covers many vessel sizes
  • 360° continuous steering for precise low‑speed maneuvering
  • Sternguard In‑Water Serviceable Seal (IWSS) enables underwater maintenance, reducing dry‑dock time
  • Integrated fine‑filtration hydraulic system extends bearing and gear life
  • Optional retractable version (WST‑R) reduces drag when not in use
Weaknesses
  • High initial capital cost compared with simpler fixed thrusters
  • Requires dedicated tunnel space in hull, limiting installation on smaller vessels
  • Complex overhaul procedures (5‑year inspection, 10‑year major rebuild) need specialised tools and trained personnel
  • Noise and vibration at the upper end of the power band may require additional mitigation measures
  • Weight and size can affect vessel stability if not properly accounted for
Typical Vessels: Container shipsCrude oil tankersLNG carriersBulk carriersOffshore supply vessels (OSV)Cruise linersFPSOs
Certifications: DNV GLABSLR
Decision Guide: Choose if you need high thrust for port entry/exit, dynamic positioning or emergency maneuvering on large vessels and want reduced downtime thanks to the IWSS. Avoid if vessel size or budget cannot accommodate a tunnel thruster, or if an azimuth pod/azipod offers better overall propulsion efficiency for your operational profile.
Use Cases: Deployed on deep‑draft ships that require strong bow or stern thrust for docking in confined ports, as auxiliary power for DP‑2 offshore platforms, and on vessels where dry‑dock intervals must be minimised by underwater maintenance capability.
Manufacturer Datasheet
Datasheet
WST-18E embedded electric steerable thruster - Wärtsilä
· Embedded electric drive
Model Number
WST-E
Technical Specifications
Leistungsbereich WST
700 kW bis 4900 kW
Leistungsbereich WTT
400 kW bis 5500 kW
Leistungsbereich WST-R
750 kW bis 6500 kW
Neigungswinkel (WST-R)
8-Grad Propeller-Getriebe-Neigung für 15-20% höheren Schub
Drehbereich
360° kontinuierliche Lenkung in horizontaler Ebene
Wartungsintervalle
5-year inspections, 10-year overhauls or after 40,000–56,000 operating hours
Dichtungstechnologie
Sternguard In-Water Serviceable Seal (IWSS) - vollständig unter Wasser wartbar
Ölsystem
Integrierte Hydraulik mit Feinfiltration zur Lagerverlängerung
Product Lines
  • WST - Steerable Thrusters (700-4900 kW)
  • WTT - Transverse/Tunnel Thrusters (400-5500 kW)
  • WST-R - Retractable Steerable Thrusters (750-6500 kW)
  • WST-E - Electric Steerable Thrusters (WST-18E embedded electric)
  • Underwater-Mountable Steerable Thrusters
Common Failures & Inspection Points
  • Area: Propeller-Blätter: Erosion, Korrosion, Kantenschäden, Verschleißmuster
    Check: Perform visual inspection and NDT (non-destructive testing) according to OEM and classification society standards. Polishing in combination with edge damage repair increases operating efficiency by 2-5%. Check for pitting, erosion patterns and corrosion spots; document severe pitting areas.
  • Area: Propeller blade foot seals: wear, leakage, water ingress
    Check: 5-year overhaul: Disassemble and inspect all seals. 10-year overhaul: Complete replacement of blade foot O-rings. Check for water penetration in jet thruster assembly. Seals are critical for system protection.
  • Area: Wellendichtungen (Shaft Seals): Abnutzung, Leckage, Austauschbedarf
    Check: Measure propeller shaft wear with poker gauge (between last two stern tube seals). Perform complete inspection of tooth clearance, tooth pattern and shaft seals. 5-year overhaul: seal replacement. 10-year overhaul: comprehensive replacement.
  • Area: Bearings (Roller Bearings): wear, bearing clearance, preload, failure symptoms
    Check: 5-year overhaul: Check bearing clearance and wear. 10-year overhaul: Complete bearing replacement, reset preload, perform NDT inspection. Check main bearing axial clearance wear with feeler gauge (0.1 mm); maximum wear limit 2 mm. Use Wärtsilä bearing wear measurement system for remote monitoring of propeller shaft shoulder.
  • Area: Hydrauliksystem: Öl-Verschmutzung (Wasser, Partikel), Filtration, Ölqualität
    Check: Check gear oil regularly. At critical wear limits: partial change (bleed-and-feed) or complete oil change. Monitor water content in oil (critical >1000 ppm). Check fine filtration system and redundant filter options. Continuously filter out water ingress. Use all Wärtsilä-approved spare parts. 5-10-year overhaul: Perform oil change and filter maintenance.
  • Area: Sternguard In-Water Serviceable Seal (IWSS): seal integrity, maintenance possible underwater
    Check: Check for oil leakage at outer seal. Inspect inflatable emergency seal and inner rope guard. Fully serviceable underwater without habitat or discharge. Measure seal gap and wear. Check retrofit compatibility with other seal types. Confirm compatibility with EAL and mineral oils.

Type-universal inspection/service points for Bow/Stern Thrusters (Wärtsilä, Mega-Schwarm 2026-06). Per-model specs not auto-filled.

Strengths
  • Integrated electric motor eliminates hydraulic lines, reducing hull penetrations and potential leak points
  • Sternguard In‑Water Serviceable Seal (IWSS) allows maintenance without dry‑docking
  • 360° continuous steering provides superior maneuverability for dynamic positioning
  • High efficiency across the 700 kW–4.9 MW power band, lowering fuel consumption of auxiliary generators
  • Reduced vibration and noise compared with hydraulic thrusters
Weaknesses
  • Higher capital cost than comparable hydraulic thrusters
  • Requires substantial shipboard electrical generation capacity and cooling infrastructure
  • Thermal management of the electric motor can be critical in hot climates
  • Limited thrust‑to‑weight ratio for very high‑power applications (>4 MW) compared with some large hydraulic units
  • Spare parts inventory must include specialised electric motor components
Typical Vessels: LNG carrierCruise shipOffshore supply vessel (OSV)DP2/DP3 container or bulk carrierFerry with tight port manoeuvring requirements
Certifications: DNVABSLR
Decision Guide: Choose if: the vessel already has a robust electrical power plant, requires frequent low‑speed manoeuvring or DP operation, and wants to minimise hull penetrations and maintenance downtime. Avoid if: the ship lacks sufficient electrical generation capacity, budget constraints prohibit higher upfront cost, or thrust requirements exceed the upper limit of the WST‑18E series.
Use Cases: The WST‑18E is typically installed on new builds where dynamic positioning, tight berth handling, or ice‑class operations demand precise thrust control. It is common on LNG carriers for berthing in constrained terminals, cruise ships for port entry without tug assistance, and offshore supply vessels that need rapid lateral movement while maintaining station‑keeping.
Manufacturer Datasheet
Datasheet
Wärtsilä Retractable Thrusters WST-R
· Retractable steerable thruster
Model Number
Wartsila Retractable Thruster
Technical Specifications
Leistungsbereich WST
700 kW bis 4900 kW
Leistungsbereich WTT
400 kW bis 5500 kW
Leistungsbereich WST-R
750 kW bis 6500 kW
Neigungswinkel (WST-R)
8-Grad Propeller-Getriebe-Neigung für 15-20% höheren Schub
Drehbereich
360° kontinuierliche Lenkung in horizontaler Ebene
Wartungsintervalle
5-year inspections, 10-year overhauls or after 40,000–56,000 operating hours
Dichtungstechnologie
Sternguard In-Water Serviceable Seal (IWSS) - vollständig unter Wasser wartbar
Ölsystem
Integrierte Hydraulik mit Feinfiltration zur Lagerverlängerung
Product Lines
  • WST - Steerable Thrusters (700-4900 kW)
  • WTT - Transverse/Tunnel Thrusters (400-5500 kW)
  • WST-R - Retractable Steerable Thrusters (750-6500 kW)
  • WST-E - Electric Steerable Thrusters (WST-18E embedded electric)
  • Underwater-Mountable Steerable Thrusters
Common Failures & Inspection Points
  • Area: Propeller-Blätter: Erosion, Korrosion, Kantenschäden, Verschleißmuster
    Check: Perform visual inspection and NDT (non-destructive testing) according to OEM and classification society standards. Polishing in combination with edge damage repair increases operating efficiency by 2-5%. Check for pitting, erosion patterns and corrosion spots; document severe pitting areas.
  • Area: Propeller blade foot seals: wear, leakage, water ingress
    Check: 5-year overhaul: Disassemble and inspect all seals. 10-year overhaul: Complete replacement of blade foot O-rings. Check for water penetration in jet thruster assembly. Seals are critical for system protection.
  • Area: Wellendichtungen (Shaft Seals): Abnutzung, Leckage, Austauschbedarf
    Check: Measure propeller shaft wear with poker gauge (between last two stern tube seals). Perform complete inspection of tooth clearance, tooth pattern and shaft seals. 5-year overhaul: seal replacement. 10-year overhaul: comprehensive replacement.
  • Area: Bearings (Roller Bearings): wear, bearing clearance, preload, failure symptoms
    Check: 5-year overhaul: Check bearing clearance and wear. 10-year overhaul: Complete bearing replacement, reset preload, perform NDT inspection. Check main bearing axial clearance wear with feeler gauge (0.1 mm); maximum wear limit 2 mm. Use Wärtsilä bearing wear measurement system for remote monitoring of propeller shaft shoulder.
  • Area: Hydrauliksystem: Öl-Verschmutzung (Wasser, Partikel), Filtration, Ölqualität
    Check: Check gear oil regularly. At critical wear limits: partial change (bleed-and-feed) or complete oil change. Monitor water content in oil (critical >1000 ppm). Check fine filtration system and redundant filter options. Continuously filter out water ingress. Use all Wärtsilä-approved spare parts. 5-10-year overhaul: Perform oil change and filter maintenance.
  • Area: Sternguard In-Water Serviceable Seal (IWSS): seal integrity, maintenance possible underwater
    Check: Check for oil leakage at outer seal. Inspect inflatable emergency seal and inner rope guard. Fully serviceable underwater without habitat or discharge. Measure seal gap and wear. Check retrofit compatibility with other seal types. Confirm compatibility with EAL and mineral oils.

Type-universal inspection/service points for Bow/Stern Thrusters (Wärtsilä, Mega-Schwarm 2026-06). Per-model specs not auto-filled.

Strengths
  • Very wide power range (750‑6500 kW) covering most large commercial vessels
  • Retractable design reduces hull resistance when the thruster is not needed
  • 8° propeller‑gear tilt provides 15‑20% higher thrust compared with standard units
  • Sternguard In‑Water Serviceable Seal (IWSS) allows underwater maintenance without dry‑docking
  • Integrated hydraulic system with fine oil filtration extends bearing life and reduces downtime
Weaknesses
  • Higher capital cost than fixed thrusters of similar power
  • Complex retractable mechanism requires more space in the hull and specialised installation
  • Maintenance intervals (5‑year inspection, 10‑year overhaul) are stricter due to moving parts
  • Requires vessel design accommodation for retraction housing and sealing penetrations
Typical Vessels: Container shipBulk carrierTankerCruise linerOffshore supply vesselLNG/LPG carrier
Certifications: DNV
Decision Guide: Choose if you need high thrust for large vessels, want drag reduction when the thruster is idle, or require underwater serviceability without dry‑docking. Avoid if budget constraints are tight, hull space for a retraction system is limited, or vessel operations do not demand the extra thrust capability.
Use Cases: The WST‑R is typically installed on large ocean‑going vessels that need precise low‑speed maneuvering and dynamic positioning – e.g., container ships entering congested ports, cruise ships docking, offshore supply vessels maintaining station, and tankers requiring tight berth control. Its retractable feature also benefits vessels that spend long periods cruising at speed where thruster drag would otherwise reduce fuel efficiency.
Manufacturer Datasheet
Datasheet
Wärtsilä Underwater Mountable Steerable Thrusters
· Steerable azimuth thruster
Model Number
Wartsila UMT
Technical Specifications
Leistungsbereich WST
700 kW bis 4900 kW
Leistungsbereich WTT
400 kW bis 5500 kW
Leistungsbereich WST-R
750 kW bis 6500 kW
Neigungswinkel (WST-R)
8-Grad Propeller-Getriebe-Neigung für 15-20% höheren Schub
Drehbereich
360° kontinuierliche Lenkung in horizontaler Ebene
Wartungsintervalle
5-year inspections, 10-year overhauls or after 40,000–56,000 operating hours
Dichtungstechnologie
Sternguard In-Water Serviceable Seal (IWSS) - vollständig unter Wasser wartbar
Ölsystem
Integrierte Hydraulik mit Feinfiltration zur Lagerverlängerung
Product Lines
  • WST - Steerable Thrusters (700-4900 kW)
  • WTT - Transverse/Tunnel Thrusters (400-5500 kW)
  • WST-R - Retractable Steerable Thrusters (750-6500 kW)
  • WST-E - Electric Steerable Thrusters (WST-18E embedded electric)
  • Underwater-Mountable Steerable Thrusters
Power range (kW)
700-4900
Common Failures & Inspection Points
  • Area: Propeller-Blätter: Erosion, Korrosion, Kantenschäden, Verschleißmuster
    Check: Perform visual inspection and NDT (non-destructive testing) according to OEM and classification society standards. Polishing in combination with edge damage repair increases operating efficiency by 2-5%. Check for pitting, erosion patterns and corrosion spots; document severe pitting areas.
  • Area: Propeller blade foot seals: wear, leakage, water ingress
    Check: 5-year overhaul: Disassemble and inspect all seals. 10-year overhaul: Complete replacement of blade foot O-rings. Check for water penetration in jet thruster assembly. Seals are critical for system protection.
  • Area: Wellendichtungen (Shaft Seals): Abnutzung, Leckage, Austauschbedarf
    Check: Measure propeller shaft wear with poker gauge (between last two stern tube seals). Perform complete inspection of tooth clearance, tooth pattern and shaft seals. 5-year overhaul: seal replacement. 10-year overhaul: comprehensive replacement.
  • Area: Bearings (Roller Bearings): wear, bearing clearance, preload, failure symptoms
    Check: 5-year overhaul: Check bearing clearance and wear. 10-year overhaul: Complete bearing replacement, reset preload, perform NDT inspection. Check main bearing axial clearance wear with feeler gauge (0.1 mm); maximum wear limit 2 mm. Use Wärtsilä bearing wear measurement system for remote monitoring of propeller shaft shoulder.
  • Area: Hydrauliksystem: Öl-Verschmutzung (Wasser, Partikel), Filtration, Ölqualität
    Check: Check gear oil regularly. At critical wear limits: partial change (bleed-and-feed) or complete oil change. Monitor water content in oil (critical >1000 ppm). Check fine filtration system and redundant filter options. Continuously filter out water ingress. Use all Wärtsilä-approved spare parts. 5-10-year overhaul: Perform oil change and filter maintenance.
  • Area: Sternguard In-Water Serviceable Seal (IWSS): seal integrity, maintenance possible underwater
    Check: Check for oil leakage at outer seal. Inspect inflatable emergency seal and inner rope guard. Fully serviceable underwater without habitat or discharge. Measure seal gap and wear. Check retrofit compatibility with other seal types. Confirm compatibility with EAL and mineral oils.

Type-universal inspection/service points for Bow/Stern Thrusters (Wärtsilä, Mega-Schwarm 2026-06). Per-model specs not auto-filled.

Strengths
  • Underwater serviceable Sternguard IWSS seal eliminates need for dry‑dock during overhauls
  • Full 360° azimuth gives superior maneuverability and DP capability
  • Wide power range (700 kW–6.5 MW) covers many vessel sizes and propulsion requirements
  • Integrated hydraulic system with fine filtration extends bearing life
  • Retractable version (WST‑R) reduces hull resistance when thruster is not in use
Weaknesses
  • Higher capital cost compared with conventional tunnel or fixed‑pitch thrusters
  • Complex installation and maintenance require specialised tools and trained personnel
  • Spare‑part logistics can be challenging for vessels operating far from major ports
  • Large hull opening needed; may limit applicability on smaller ships
  • Seal performance is critical – improper underwater servicing can lead to leaks
Typical Vessels: Container shipCruise linerLNG carrierOffshore supply vesselFPSOVery large crude carrier (VLCC)Bulk carrier with DP requirement
Certifications: DNV GL class approvedABS class approvedLR class approved
Decision Guide: Choose if the vessel requires high thrust, full‑azimuth steering and wants to minimise dry‑dock time through underwater serviceability – especially for DP‑equipped or large ships operating in confined ports. Avoid if budget constraints favour a simpler tunnel thruster, the vessel size is small, or the operator lacks access to specialised maintenance facilities.
Use Cases: The UMT family is typically deployed on large ocean‑going vessels that need precise low‑speed manoeuvring and dynamic positioning, such as cruise ships entering tight harbours, LNG carriers docking at offshore terminals, and FPSOs maintaining station. Retractable models are used where drag reduction during transit is critical.
Manufacturer Datasheet
Datasheet
Wärtsilä electric pod and thruster seals
· In-Water Serviceable Seal (IWSS)
Model Number
Wartsila Electric Pod And Thruster Seals
Technical Specifications
Leistungsbereich WST
700 kW bis 4900 kW
Leistungsbereich WTT
400 kW bis 5500 kW
Leistungsbereich WST-R
750 kW bis 6500 kW
Neigungswinkel (WST-R)
8-Grad Propeller-Getriebe-Neigung für 15-20% höheren Schub
Drehbereich
360° kontinuierliche Lenkung in horizontaler Ebene
Wartungsintervalle
5-year inspections, 10-year overhauls or after 40,000–56,000 operating hours
Dichtungstechnologie
Sternguard In-Water Serviceable Seal (IWSS) - vollständig unter Wasser wartbar
Ölsystem
Integrierte Hydraulik mit Feinfiltration zur Lagerverlängerung
Product Lines
  • WST - Steerable Thrusters (700-4900 kW)
  • WTT - Transverse/Tunnel Thrusters (400-5500 kW)
  • WST-R - Retractable Steerable Thrusters (750-6500 kW)
  • WST-E - Electric Steerable Thrusters (WST-18E embedded electric)
  • Underwater-Mountable Steerable Thrusters
Common Failures & Inspection Points
  • Area: Propeller-Blätter: Erosion, Korrosion, Kantenschäden, Verschleißmuster
    Check: Perform visual inspection and NDT (non-destructive testing) according to OEM and classification society standards. Polishing in combination with edge damage repair increases operating efficiency by 2-5%. Check for pitting, erosion patterns and corrosion spots; document severe pitting areas.
  • Area: Propeller blade foot seals: wear, leakage, water ingress
    Check: 5-year overhaul: Disassemble and inspect all seals. 10-year overhaul: Complete replacement of blade foot O-rings. Check for water penetration in jet thruster assembly. Seals are critical for system protection.
  • Area: Wellendichtungen (Shaft Seals): Abnutzung, Leckage, Austauschbedarf
    Check: Measure propeller shaft wear with poker gauge (between last two stern tube seals). Perform complete inspection of tooth clearance, tooth pattern and shaft seals. 5-year overhaul: seal replacement. 10-year overhaul: comprehensive replacement.
  • Area: Bearings (Roller Bearings): wear, bearing clearance, preload, failure symptoms
    Check: 5-year overhaul: Check bearing clearance and wear. 10-year overhaul: Complete bearing replacement, reset preload, perform NDT inspection. Check main bearing axial clearance wear with feeler gauge (0.1 mm); maximum wear limit 2 mm. Use Wärtsilä bearing wear measurement system for remote monitoring of propeller shaft shoulder.
  • Area: Hydrauliksystem: Öl-Verschmutzung (Wasser, Partikel), Filtration, Ölqualität
    Check: Check gear oil regularly. At critical wear limits: partial change (bleed-and-feed) or complete oil change. Monitor water content in oil (critical >1000 ppm). Check fine filtration system and redundant filter options. Continuously filter out water ingress. Use all Wärtsilä-approved spare parts. 5-10-year overhaul: Perform oil change and filter maintenance.
  • Area: Sternguard In-Water Serviceable Seal (IWSS): seal integrity, maintenance possible underwater
    Check: Check for oil leakage at outer seal. Inspect inflatable emergency seal and inner rope guard. Fully serviceable underwater without habitat or discharge. Measure seal gap and wear. Check retrofit compatibility with other seal types. Confirm compatibility with EAL and mineral oils.

Type-universal inspection/service points for Bow/Stern Thrusters (Wärtsilä, Mega-Schwarm 2026-06). Per-model specs not auto-filled.

Strengths
  • Underwater‑serviceable seal eliminates the need for dry‑docking to replace worn seals, reducing downtime.
  • Broad power envelope (700 kW‑4.9 MW for WST, up to 6.5 MW for retractable models) fits many high‑power vessels.
  • Continuous 360° steering offers superior maneuverability and DP performance.
  • Integrated hydraulic oil system with fine filtration extends bearing life and lowers maintenance frequency.
  • Standardised product families (WST, WTT, WST‑R, etc.) simplify spares logistics.
Weaknesses
  • Higher capital cost compared with conventional lip seals or non‑serviceable designs.
  • Requires specialised Wärtsilä support and tooling for seal inspection/replacement under water.
  • Major overhauls (10‑year) still demand dry‑docking and shaft removal, incurring significant shipyard time.
  • Installation space constraints – pod/shaft geometry may not suit all hull forms.
  • Sensitivity to water ingress; seal performance degrades if oil‑water separation exceeds 1 000 ppm.
Typical Vessels: Container shipsBulk carriersLNG/LPG carriersCruise linersOffshore supply vesselsDP‑class workboats
Certifications: DNV GLABSLR
Decision Guide: Choose if: you need high‑power bow thrusters with minimal dry‑dock intervals, operate DP or require precise port manoeuvring, and have access to Wärtsilä service support. Avoid if: budget constraints dominate, vessel layout cannot accommodate the pod geometry, or you lack a nearby authorised service centre for underwater seal work.
Use Cases: The system is typically installed on large ocean‑going vessels that rely on dynamic positioning or tight port handling – e.g., LNG carriers using bow thrusters to counteract wind and current during loading, cruise ships docking in confined harbours, and offshore supply vessels manoeuvring alongside rigs. The underwater serviceable seal allows routine inspections while the vessel remains afloat, extending operational availability.
Manufacturer Datasheet
Datasheet
Ship thrusters and thruster solutions - Wärtsilä
· Steerable azimuth thruster with integrated hydraulic drive
Model Number
Thrusters
Technical Specifications
Leistungsbereich WST
700 kW bis 4900 kW
Leistungsbereich WTT
400 kW bis 5500 kW
Leistungsbereich WST-R
750 kW bis 6500 kW
Neigungswinkel (WST-R)
8-Grad Propeller-Getriebe-Neigung für 15-20% höheren Schub
Drehbereich
360° kontinuierliche Lenkung in horizontaler Ebene
Wartungsintervalle
5-year inspections, 10-year overhauls or after 40,000–56,000 operating hours
Dichtungstechnologie
Sternguard In-Water Serviceable Seal (IWSS) - vollständig unter Wasser wartbar
Ölsystem
Integrierte Hydraulik mit Feinfiltration zur Lagerverlängerung
Product Lines
  • WST - Steerable Thrusters (700-4900 kW)
  • WTT - Transverse/Tunnel Thrusters (400-5500 kW)
  • WST-R - Retractable Steerable Thrusters (750-6500 kW)
  • WST-E - Electric Steerable Thrusters (WST-18E embedded electric)
  • Underwater-Mountable Steerable Thrusters
Common Failures & Inspection Points
  • Area: Propeller-Blätter: Erosion, Korrosion, Kantenschäden, Verschleißmuster
    Check: Perform visual inspection and NDT (non-destructive testing) according to OEM and classification society standards. Polishing in combination with edge damage repair increases operating efficiency by 2-5%. Check for pitting, erosion patterns and corrosion spots; document severe pitting areas.
  • Area: Propeller blade foot seals: wear, leakage, water ingress
    Check: 5-year overhaul: Disassemble and inspect all seals. 10-year overhaul: Complete replacement of blade foot O-rings. Check for water penetration in jet thruster assembly. Seals are critical for system protection.
  • Area: Wellendichtungen (Shaft Seals): Abnutzung, Leckage, Austauschbedarf
    Check: Measure propeller shaft wear with poker gauge (between last two stern tube seals). Perform complete inspection of tooth clearance, tooth pattern and shaft seals. 5-year overhaul: seal replacement. 10-year overhaul: comprehensive replacement.
  • Area: Bearings (Roller Bearings): wear, bearing clearance, preload, failure symptoms
    Check: 5-year overhaul: Check bearing clearance and wear. 10-year overhaul: Complete bearing replacement, reset preload, perform NDT inspection. Check main bearing axial clearance wear with feeler gauge (0.1 mm); maximum wear limit 2 mm. Use Wärtsilä bearing wear measurement system for remote monitoring of propeller shaft shoulder.
  • Area: Hydrauliksystem: Öl-Verschmutzung (Wasser, Partikel), Filtration, Ölqualität
    Check: Check gear oil regularly. At critical wear limits: partial change (bleed-and-feed) or complete oil change. Monitor water content in oil (critical >1000 ppm). Check fine filtration system and redundant filter options. Continuously filter out water ingress. Use all Wärtsilä-approved spare parts. 5-10-year overhaul: Perform oil change and filter maintenance.
  • Area: Sternguard In-Water Serviceable Seal (IWSS): seal integrity, maintenance possible underwater
    Check: Check for oil leakage at outer seal. Inspect inflatable emergency seal and inner rope guard. Fully serviceable underwater without habitat or discharge. Measure seal gap and wear. Check retrofit compatibility with other seal types. Confirm compatibility with EAL and mineral oils.

Type-universal inspection/service points for Bow/Stern Thrusters (Wärtsilä, Mega-Schwarm 2026-06). Per-model specs not auto-filled.

Strengths
  • Wide power range (700 kW – 4.9 MW) covering many vessel sizes
  • Continuous 360° steering for superior maneuverability and DP capability
  • Sternguard In‑Water Serviceable Seal allows underwater maintenance, reducing dry‑dock time
  • Modular product family (steerable, retractable, electric) to match specific installation constraints
  • Optimised blade geometry and low shaft speed give high thrust efficiency
Weaknesses
  • Higher capital cost compared with fixed tunnel thrusters of similar power
  • Complex hydraulic system requires regular oil quality monitoring and filtration
  • Larger hull penetration can affect structural integrity and may need reinforcement
  • Maintenance intervals (5‑year inspection, 10‑year overhaul) are still significant for operators
  • Spare‑part availability can be limited in remote ports without Wärtsilä service network
Typical Vessels: Container shipLNG carrierCruise linerOffshore supply vesselRo‑Ro ferryLarge tankerBulk carrier (≥30 kt) with DP requirements
Certifications: DNV GL Type ApprovalABS Classification
Decision Guide: Choose if the vessel requires high maneuverability, dynamic positioning or operates in confined ports where rapid lateral thrust is essential. Avoid if budget constraints favour a simpler fixed tunnel thruster on smaller vessels with modest manoeuvring needs.
Use Cases: Wärtsilä bow thrusters are commonly installed on large commercial ships for port entry and departure, on offshore support vessels to maintain position during subsea operations, and on cruise ships where precise docking is critical. The retractable versions are favoured on ice‑class or shallow‑draft vessels to minimise hull resistance when not in use.
Manufacturer Datasheet
Datasheet
Wärtsilä OPTI-DP Engagement Tool
· DP optimisation software
Model Number
Opti Dp
Technical Specifications
Leistungsbereich WST
700 kW bis 4900 kW
Leistungsbereich WTT
400 kW bis 5500 kW
Leistungsbereich WST-R
750 kW bis 6500 kW
Neigungswinkel (WST-R)
8-Grad Propeller-Getriebe-Neigung für 15-20% höheren Schub
Drehbereich
360° kontinuierliche Lenkung in horizontaler Ebene
Wartungsintervalle
5-year inspections, 10-year overhauls or after 40,000–56,000 operating hours
Dichtungstechnologie
Sternguard In-Water Serviceable Seal (IWSS) - vollständig unter Wasser wartbar
Ölsystem
Integrierte Hydraulik mit Feinfiltration zur Lagerverlängerung
Product Lines
  • WST - Steerable Thrusters (700-4900 kW)
  • WTT - Transverse/Tunnel Thrusters (400-5500 kW)
  • WST-R - Retractable Steerable Thrusters (750-6500 kW)
  • WST-E - Electric Steerable Thrusters (WST-18E embedded electric)
  • Underwater-Mountable Steerable Thrusters
Common Failures & Inspection Points
  • Area: Propeller-Blätter: Erosion, Korrosion, Kantenschäden, Verschleißmuster
    Check: Perform visual inspection and NDT (non-destructive testing) according to OEM and classification society standards. Polishing in combination with edge damage repair increases operating efficiency by 2-5%. Check for pitting, erosion patterns and corrosion spots; document severe pitting areas.
  • Area: Propeller blade foot seals: wear, leakage, water ingress
    Check: 5-year overhaul: Disassemble and inspect all seals. 10-year overhaul: Complete replacement of blade foot O-rings. Check for water penetration in jet thruster assembly. Seals are critical for system protection.
  • Area: Wellendichtungen (Shaft Seals): Abnutzung, Leckage, Austauschbedarf
    Check: Measure propeller shaft wear with poker gauge (between last two stern tube seals). Perform complete inspection of tooth clearance, tooth pattern and shaft seals. 5-year overhaul: seal replacement. 10-year overhaul: comprehensive replacement.
  • Area: Bearings (Roller Bearings): wear, bearing clearance, preload, failure symptoms
    Check: 5-year overhaul: Check bearing clearance and wear. 10-year overhaul: Complete bearing replacement, reset preload, perform NDT inspection. Check main bearing axial clearance wear with feeler gauge (0.1 mm); maximum wear limit 2 mm. Use Wärtsilä bearing wear measurement system for remote monitoring of propeller shaft shoulder.
  • Area: Hydrauliksystem: Öl-Verschmutzung (Wasser, Partikel), Filtration, Ölqualität
    Check: Check gear oil regularly. At critical wear limits: partial change (bleed-and-feed) or complete oil change. Monitor water content in oil (critical >1000 ppm). Check fine filtration system and redundant filter options. Continuously filter out water ingress. Use all Wärtsilä-approved spare parts. 5-10-year overhaul: Perform oil change and filter maintenance.
  • Area: Sternguard In-Water Serviceable Seal (IWSS): seal integrity, maintenance possible underwater
    Check: Check for oil leakage at outer seal. Inspect inflatable emergency seal and inner rope guard. Fully serviceable underwater without habitat or discharge. Measure seal gap and wear. Check retrofit compatibility with other seal types. Confirm compatibility with EAL and mineral oils.

Type-universal inspection/service points for Bow/Stern Thrusters (Wärtsilä, Mega-Schwarm 2026-06). Per-model specs not auto-filled.

Strengths
  • Direct integration with Wärtsilä WST, WTT and WST‑R thruster data libraries ensures accurate performance predictions.
  • Provides lifecycle cost analysis including maintenance intervals (5‑year inspections, 10‑year overhauls) and oil‑filtering strategies.
  • Enables 360° thrust vector simulation for both static and DP operating modes, helping to meet class DP requirements early in design.
  • Supports what‑if scenarios for different power ratings (700 kW–6.5 MW) and propeller pitch angles, facilitating optimal thruster selection.
  • Includes built‑in alerts for known failure points such as blade‑foot seal wear or shaft bearing degradation.
Weaknesses
  • Applicable only to Wärtsilä thruster families; mixed‑manufacturer installations require separate analysis tools.
  • Requires a licensed installation and periodic software updates, adding to total ownership cost.
  • Advanced DP scenario modelling may need high‑performance computing resources not available on all shipyards.
  • No formal regulatory certification (e.g., IMO D‑2) for the software itself; compliance still depends on downstream system approval.
  • User training is necessary to interpret maintenance‑interval recommendations correctly.
Typical Vessels: Offshore Support VesselDrillshipFPSOLNG Carrier with DPCruise Ship (DP‑enabled)Naval Auxiliary
Decision Guide: Choose if: you are planning a new build or major retrofit that will use Wärtsilä steerable thrusters and need integrated DP performance, cost‑of‑ownership and maintenance planning. Avoid if: the vessel uses a heterogeneous thruster fleet, budget constraints preclude software licensing, or you require a tool with formal IMO/USCG certification for DP system approval.
Use Cases: The tool is typically deployed during preliminary design to size bow thrusters for DP‑class vessels, during detailed engineering to fine‑tune thrust allocation, and in operational planning to schedule inspections and overhauls based on the known wear patterns of blade seals, shaft bearings and hydraulic oil quality.
Manufacturer Datasheet
Datasheet
Elogrid by Wärtsilä - Boost thrust and save fuel for your ship
· Steerable electric/hydraulic thruster with IWSS seal
Model Number
Elogrid By Wartsila
Technical Specifications
Leistungsbereich WST
700 kW bis 4900 kW
Leistungsbereich WTT
400 kW bis 5500 kW
Leistungsbereich WST-R
750 kW bis 6500 kW
Neigungswinkel (WST-R)
8-Grad Propeller-Getriebe-Neigung für 15-20% höheren Schub
Drehbereich
360° kontinuierliche Lenkung in horizontaler Ebene
Wartungsintervalle
5-year inspections, 10-year overhauls or after 40,000–56,000 operating hours
Dichtungstechnologie
Sternguard In-Water Serviceable Seal (IWSS) - vollständig unter Wasser wartbar
Ölsystem
Integrierte Hydraulik mit Feinfiltration zur Lagerverlängerung
Product Lines
  • WST - Steerable Thrusters (700-4900 kW)
  • WTT - Transverse/Tunnel Thrusters (400-5500 kW)
  • WST-R - Retractable Steerable Thrusters (750-6500 kW)
  • WST-E - Electric Steerable Thrusters (WST-18E embedded electric)
  • Underwater-Mountable Steerable Thrusters
Common Failures & Inspection Points
  • Area: Propeller-Blätter: Erosion, Korrosion, Kantenschäden, Verschleißmuster
    Check: Perform visual inspection and NDT (non-destructive testing) according to OEM and classification society standards. Polishing in combination with edge damage repair increases operating efficiency by 2-5%. Check for pitting, erosion patterns and corrosion spots; document severe pitting areas.
  • Area: Propeller blade foot seals: wear, leakage, water ingress
    Check: 5-year overhaul: Disassemble and inspect all seals. 10-year overhaul: Complete replacement of blade foot O-rings. Check for water penetration in jet thruster assembly. Seals are critical for system protection.
  • Area: Wellendichtungen (Shaft Seals): Abnutzung, Leckage, Austauschbedarf
    Check: Measure propeller shaft wear with poker gauge (between last two stern tube seals). Perform complete inspection of tooth clearance, tooth pattern and shaft seals. 5-year overhaul: seal replacement. 10-year overhaul: comprehensive replacement.
  • Area: Bearings (Roller Bearings): wear, bearing clearance, preload, failure symptoms
    Check: 5-year overhaul: Check bearing clearance and wear. 10-year overhaul: Complete bearing replacement, reset preload, perform NDT inspection. Check main bearing axial clearance wear with feeler gauge (0.1 mm); maximum wear limit 2 mm. Use Wärtsilä bearing wear measurement system for remote monitoring of propeller shaft shoulder.
  • Area: Hydrauliksystem: Öl-Verschmutzung (Wasser, Partikel), Filtration, Ölqualität
    Check: Check gear oil regularly. At critical wear limits: partial change (bleed-and-feed) or complete oil change. Monitor water content in oil (critical >1000 ppm). Check fine filtration system and redundant filter options. Continuously filter out water ingress. Use all Wärtsilä-approved spare parts. 5-10-year overhaul: Perform oil change and filter maintenance.
  • Area: Sternguard In-Water Serviceable Seal (IWSS): seal integrity, maintenance possible underwater
    Check: Check for oil leakage at outer seal. Inspect inflatable emergency seal and inner rope guard. Fully serviceable underwater without habitat or discharge. Measure seal gap and wear. Check retrofit compatibility with other seal types. Confirm compatibility with EAL and mineral oils.

Type-universal inspection/service points for Bow/Stern Thrusters (Wärtsilä, Mega-Schwarm 2026-06). Per-model specs not auto-filled.

Strengths
  • Wide power range (700 kW – 4.9 MW) covering medium to ultra‑large vessels
  • Continuous 360° steering without mechanical stop‑cage, enabling precise manoeuvring
  • Sternguard In‑Water Serviceable Seal allows underwater maintenance, reducing dry‑dock intervals
  • Integrated fine‑filtration hydraulic system extends bearing life and improves fuel efficiency
  • Retractable version (WST‑R) offers 15‑20 % higher thrust via propeller tilt
Weaknesses
  • Higher upfront capital cost compared with conventional fixed bow thrusters
  • Complex maintenance requiring specialised tools, training and OEM support
  • Hydraulic oil quality must be tightly controlled; contamination can lead to premature wear
  • Retractable installations need hull penetrations and careful structural design
  • Spare‑part logistics may be longer for remote ports
Typical Vessels: Container ships (>150 m)Cruise linersLNG carriersLarge tankers (crude, product)Offshore supply vessels with DP2/DP3Ro‑Ro and ferry vessels
Certifications: IMO Type ApprovalDNV GL Classification approvalABS approved design
Decision Guide: Choose if the vessel requires high thrust for tight port manoeuvring, dynamic positioning or ice‑class operations, and when reduced dry‑dock time is a priority. Avoid if budget constraints limit capital expenditure, the ship’s size does not justify the power range, or the operator lacks access to specialised Wärtsilä maintenance support.
Use Cases: Elogrid thrusters are typically installed at the bow of large commercial vessels to provide rapid lateral thrust during berthing, un‑berthing and low‑speed manoeuvres. They also serve as a primary DP actuator on offshore supply ships, enabling precise station‑keeping in harsh sea states while the IWSS seal allows routine inspections without removing the thruster from the water.
Manufacturer Datasheet
Datasheet
Wärtsilä Wärtsilä CT50
Wärtsilä CT50
· 50.0 kW · Tunnel bow thruster
Series
CT
Power (kW)
50
Tunnel diameter (mm)
600
Type
tunnel
Technical Specifications
Leistungsbereich WST
700 kW bis 4900 kW
Leistungsbereich WTT
400 kW bis 5500 kW
Leistungsbereich WST-R
750 kW bis 6500 kW
Neigungswinkel (WST-R)
8-Grad Propeller-Getriebe-Neigung für 15-20% höheren Schub
Drehbereich
360° kontinuierliche Lenkung in horizontaler Ebene
Wartungsintervalle
5-year inspections, 10-year overhauls or after 40,000–56,000 operating hours
Dichtungstechnologie
Sternguard In-Water Serviceable Seal (IWSS) - vollständig unter Wasser wartbar
Ölsystem
Integrierte Hydraulik mit Feinfiltration zur Lagerverlängerung
Product Lines
  • WST - Steerable Thrusters (700-4900 kW)
  • WTT - Transverse/Tunnel Thrusters (400-5500 kW)
  • WST-R - Retractable Steerable Thrusters (750-6500 kW)
  • WST-E - Electric Steerable Thrusters (WST-18E embedded electric)
  • Underwater-Mountable Steerable Thrusters
Common Failures & Inspection Points
  • Area: Propeller-Blätter: Erosion, Korrosion, Kantenschäden, Verschleißmuster
    Check: Perform visual inspection and NDT (non-destructive testing) according to OEM and classification society standards. Polishing in combination with edge damage repair increases operating efficiency by 2-5%. Check for pitting, erosion patterns and corrosion spots; document severe pitting areas.
  • Area: Propeller blade foot seals: wear, leakage, water ingress
    Check: 5-year overhaul: Disassemble and inspect all seals. 10-year overhaul: Complete replacement of blade foot O-rings. Check for water penetration in jet thruster assembly. Seals are critical for system protection.
  • Area: Wellendichtungen (Shaft Seals): Abnutzung, Leckage, Austauschbedarf
    Check: Measure propeller shaft wear with poker gauge (between last two stern tube seals). Perform complete inspection of tooth clearance, tooth pattern and shaft seals. 5-year overhaul: seal replacement. 10-year overhaul: comprehensive replacement.
  • Area: Bearings (Roller Bearings): wear, bearing clearance, preload, failure symptoms
    Check: 5-year overhaul: Check bearing clearance and wear. 10-year overhaul: Complete bearing replacement, reset preload, perform NDT inspection. Check main bearing axial clearance wear with feeler gauge (0.1 mm); maximum wear limit 2 mm. Use Wärtsilä bearing wear measurement system for remote monitoring of propeller shaft shoulder.
  • Area: Hydrauliksystem: Öl-Verschmutzung (Wasser, Partikel), Filtration, Ölqualität
    Check: Check gear oil regularly. At critical wear limits: partial change (bleed-and-feed) or complete oil change. Monitor water content in oil (critical >1000 ppm). Check fine filtration system and redundant filter options. Continuously filter out water ingress. Use all Wärtsilä-approved spare parts. 5-10-year overhaul: Perform oil change and filter maintenance.
  • Area: Sternguard In-Water Serviceable Seal (IWSS): seal integrity, maintenance possible underwater
    Check: Check for oil leakage at outer seal. Inspect inflatable emergency seal and inner rope guard. Fully serviceable underwater without habitat or discharge. Measure seal gap and wear. Check retrofit compatibility with other seal types. Confirm compatibility with EAL and mineral oils.

Type-universal inspection/service points for Bow/Stern Thrusters (Wärtsilä, Mega-Schwarm 2026-06). Per-model specs not auto-filled.

Strengths
  • Low power (50 kW) and small footprint – easy integration on vessels with limited hull space
  • Sternguard In‑Water Serviceable Seal (IWSS) allows underwater inspection and minor repairs without dry‑docking
  • Integrated hydraulic drive with fine filtration extends bearing life and reduces oil contamination risk
  • 360° continuous steering provides precise maneuverability in tight ports
  • Quiet operation suitable for passenger ferries and workboats
Weaknesses
  • Limited thrust compared with larger thrusters – not suited for high‑displacement ships requiring >150 kN of bollard pull
  • Tunnel diameter (600 mm) restricts propeller size, reducing efficiency at higher vessel speeds
  • Maintenance intervals (5‑year inspection, 10‑year overhaul) still required to avoid bearing and seal wear
  • Single unit – no built‑in redundancy for critical DP applications
  • Potential cavitation in very shallow water or when operating near the propeller’s design limit
Typical Vessels: Offshore supply vessel (OSV)Workboat / tug auxiliaryCoastal ferrySmall bulk carrier (<5 000 GT)Cruise ship tenderDredger
Certifications: DNV GL class approvalABS classification
Decision Guide: Choose the CT50 when a vessel under ~5 000 GT needs a compact, low‑power bow thruster with underwater serviceability and precise steering – typical for coastal operations, DP‑assist on OSVs, or passenger ferries. Avoid it on large tankers, cruise ships, or any platform requiring high thrust, redundancy, or deep‑water dynamic positioning where >150 kN of bollard pull is demanded.
Use Cases: The CT50 is commonly installed on small to medium offshore supply vessels and coastal ferries to aid docking, undocking, and low‑speed maneuvering in congested ports. It also serves as a DP‑assist thruster on workboats that require occasional precise positioning without the cost of a full‑power system.
Manufacturer Datasheet
Datasheet
Wärtsilä Wärtsilä CT100
Wärtsilä CT100
· 100.0 kW · tunnel steerable thruster with Sternguard In‑Water Serviceable Seal
Series
CT
Power (kW)
100
Tunnel diameter (mm)
800
Type
tunnel
Technical Specifications
Leistungsbereich WST
700 kW bis 4900 kW
Leistungsbereich WTT
400 kW bis 5500 kW
Leistungsbereich WST-R
750 kW bis 6500 kW
Neigungswinkel (WST-R)
8-Grad Propeller-Getriebe-Neigung für 15-20% höheren Schub
Drehbereich
360° kontinuierliche Lenkung in horizontaler Ebene
Wartungsintervalle
5-year inspections, 10-year overhauls or after 40,000–56,000 operating hours
Dichtungstechnologie
Sternguard In-Water Serviceable Seal (IWSS) - vollständig unter Wasser wartbar
Ölsystem
Integrierte Hydraulik mit Feinfiltration zur Lagerverlängerung
Product Lines
  • WST - Steerable Thrusters (700-4900 kW)
  • WTT - Transverse/Tunnel Thrusters (400-5500 kW)
  • WST-R - Retractable Steerable Thrusters (750-6500 kW)
  • WST-E - Electric Steerable Thrusters (WST-18E embedded electric)
  • Underwater-Mountable Steerable Thrusters
Common Failures & Inspection Points
  • Area: Propeller-Blätter: Erosion, Korrosion, Kantenschäden, Verschleißmuster
    Check: Perform visual inspection and NDT (non-destructive testing) according to OEM and classification society standards. Polishing in combination with edge damage repair increases operating efficiency by 2-5%. Check for pitting, erosion patterns and corrosion spots; document severe pitting areas.
  • Area: Propeller blade foot seals: wear, leakage, water ingress
    Check: 5-year overhaul: Disassemble and inspect all seals. 10-year overhaul: Complete replacement of blade foot O-rings. Check for water penetration in jet thruster assembly. Seals are critical for system protection.
  • Area: Wellendichtungen (Shaft Seals): Abnutzung, Leckage, Austauschbedarf
    Check: Measure propeller shaft wear with poker gauge (between last two stern tube seals). Perform complete inspection of tooth clearance, tooth pattern and shaft seals. 5-year overhaul: seal replacement. 10-year overhaul: comprehensive replacement.
  • Area: Bearings (Roller Bearings): wear, bearing clearance, preload, failure symptoms
    Check: 5-year overhaul: Check bearing clearance and wear. 10-year overhaul: Complete bearing replacement, reset preload, perform NDT inspection. Check main bearing axial clearance wear with feeler gauge (0.1 mm); maximum wear limit 2 mm. Use Wärtsilä bearing wear measurement system for remote monitoring of propeller shaft shoulder.
  • Area: Hydrauliksystem: Öl-Verschmutzung (Wasser, Partikel), Filtration, Ölqualität
    Check: Check gear oil regularly. At critical wear limits: partial change (bleed-and-feed) or complete oil change. Monitor water content in oil (critical >1000 ppm). Check fine filtration system and redundant filter options. Continuously filter out water ingress. Use all Wärtsilä-approved spare parts. 5-10-year overhaul: Perform oil change and filter maintenance.
  • Area: Sternguard In-Water Serviceable Seal (IWSS): seal integrity, maintenance possible underwater
    Check: Check for oil leakage at outer seal. Inspect inflatable emergency seal and inner rope guard. Fully serviceable underwater without habitat or discharge. Measure seal gap and wear. Check retrofit compatibility with other seal types. Confirm compatibility with EAL and mineral oils.

Type-universal inspection/service points for Bow/Stern Thrusters (Wärtsilä, Mega-Schwarm 2026-06). Per-model specs not auto-filled.

Strengths
  • Underwater‑serviceable IWSS seal eliminates the need for dry‑dock removal during maintenance
  • 360° continuous steering provides superior maneuverability in confined ports
  • Integrated hydraulic drive with fine filtration extends bearing life and reduces oil contamination risk
  • Compact tunnel design fits vessels with limited hull space while delivering high thrust‑to‑power ratio
  • Proven Wärtsilä brand reputation and global support network
Weaknesses
  • Limited power (100 kW) may be insufficient for large vessels or high‑wind DP operations
  • Tunnel installation requires hull penetration and careful alignment, increasing initial fit‑out time
  • Maintenance intervals (5‑year inspection, 10‑year overhaul) still impose scheduled dry‑dock periods
  • Potential cavitation noise at higher propeller speeds compared with larger diameter thrusters
  • Higher upfront cost relative to simple fixed bow thrusters of similar power
Typical Vessels: Coastal container ships (up to ~5,000 gt)Ro‑Ro ferriesOffshore supply vesselsYachts and luxury tendersSmall cruise ship auxiliaries
Certifications: DNVABS
Decision Guide: Choose the CT100 when a vessel needs precise low‑speed handling, has limited hull space for a tunnel thruster, and benefits from underwater serviceability to minimise dry‑dock downtime. Avoid it on large tankers or ultra‑large vessels where higher thrust levels (>200 kW) are required, or when budget constraints favour a fixed, lower‑cost thruster.
Use Cases: The CT100 is typically installed as a bow thruster on coastal carriers and offshore support ships to aid docking, undocking, and low‑speed manoeuvring in tight harbours. It also serves as an auxiliary DP0 system for vessels that occasionally need dynamic positioning without the expense of full‑scale DP equipment.
Manufacturer Datasheet
Datasheet
Wärtsilä Wärtsilä CT150
Wärtsilä CT150
· 150.0 kW · Tunnel-type steerable thruster with in-water serviceable seal
Series
CT
Power (kW)
150
Tunnel diameter (mm)
1000
Type
tunnel
Technical Specifications
Leistungsbereich WST
700 kW bis 4900 kW
Leistungsbereich WTT
400 kW bis 5500 kW
Leistungsbereich WST-R
750 kW bis 6500 kW
Neigungswinkel (WST-R)
8-Grad Propeller-Getriebe-Neigung für 15-20% höheren Schub
Drehbereich
360° kontinuierliche Lenkung in horizontaler Ebene
Wartungsintervalle
5-year inspections, 10-year overhauls or after 40,000–56,000 operating hours
Dichtungstechnologie
Sternguard In-Water Serviceable Seal (IWSS) - vollständig unter Wasser wartbar
Ölsystem
Integrierte Hydraulik mit Feinfiltration zur Lagerverlängerung
Product Lines
  • WST - Steerable Thrusters (700-4900 kW)
  • WTT - Transverse/Tunnel Thrusters (400-5500 kW)
  • WST-R - Retractable Steerable Thrusters (750-6500 kW)
  • WST-E - Electric Steerable Thrusters (WST-18E embedded electric)
  • Underwater-Mountable Steerable Thrusters
Common Failures & Inspection Points
  • Area: Propeller-Blätter: Erosion, Korrosion, Kantenschäden, Verschleißmuster
    Check: Perform visual inspection and NDT (non-destructive testing) according to OEM and classification society standards. Polishing in combination with edge damage repair increases operating efficiency by 2-5%. Check for pitting, erosion patterns and corrosion spots; document severe pitting areas.
  • Area: Propeller blade foot seals: wear, leakage, water ingress
    Check: 5-year overhaul: Disassemble and inspect all seals. 10-year overhaul: Complete replacement of blade foot O-rings. Check for water penetration in jet thruster assembly. Seals are critical for system protection.
  • Area: Wellendichtungen (Shaft Seals): Abnutzung, Leckage, Austauschbedarf
    Check: Measure propeller shaft wear with poker gauge (between last two stern tube seals). Perform complete inspection of tooth clearance, tooth pattern and shaft seals. 5-year overhaul: seal replacement. 10-year overhaul: comprehensive replacement.
  • Area: Bearings (Roller Bearings): wear, bearing clearance, preload, failure symptoms
    Check: 5-year overhaul: Check bearing clearance and wear. 10-year overhaul: Complete bearing replacement, reset preload, perform NDT inspection. Check main bearing axial clearance wear with feeler gauge (0.1 mm); maximum wear limit 2 mm. Use Wärtsilä bearing wear measurement system for remote monitoring of propeller shaft shoulder.
  • Area: Hydrauliksystem: Öl-Verschmutzung (Wasser, Partikel), Filtration, Ölqualität
    Check: Check gear oil regularly. At critical wear limits: partial change (bleed-and-feed) or complete oil change. Monitor water content in oil (critical >1000 ppm). Check fine filtration system and redundant filter options. Continuously filter out water ingress. Use all Wärtsilä-approved spare parts. 5-10-year overhaul: Perform oil change and filter maintenance.
  • Area: Sternguard In-Water Serviceable Seal (IWSS): seal integrity, maintenance possible underwater
    Check: Check for oil leakage at outer seal. Inspect inflatable emergency seal and inner rope guard. Fully serviceable underwater without habitat or discharge. Measure seal gap and wear. Check retrofit compatibility with other seal types. Confirm compatibility with EAL and mineral oils.

Type-universal inspection/service points for Bow/Stern Thrusters (Wärtsilä, Mega-Schwarm 2026-06). Per-model specs not auto-filled.

Strengths
  • Compact 150 kW power suitable for feeder vessels and offshore supply ships
  • Full 360° continuous steering provides excellent low‑speed manoeuvrability
  • Sternguard IWSS allows underwater maintenance, reducing dry‑dock time
  • Integrated hydraulic system with fine filtration extends bearing life
  • Standard 1000 mm tunnel diameter fits a wide range of hull designs
Weaknesses
  • Limited thrust compared with larger‑capacity thrusters; not ideal for very large vessels
  • Tunnel installation requires hull penetration and may reduce internal volume
  • Hydraulic oil system introduces contamination risk if filtration is neglected
  • Maintenance intervals (5‑year inspection, 10‑year overhaul) add lifecycle cost
  • No electric variant – unsuitable where zero‑emission propulsion is required
Typical Vessels: Feeder container shipCoastal tankerOffshore supply vesselCruise ship tenderSmall RoRo / ferry
Certifications: DNV GL Type ApprovalABS Classification approval
Decision Guide: Choose if you need a compact, steerable bow thruster with underwater serviceability for vessels up to about 150 kW and want to minimise dry‑dock maintenance. Avoid if the vessel requires higher thrust levels, an all‑electric solution, or has severe space constraints that preclude a 1000 mm tunnel.
Use Cases: Typically installed on newbuilds or retrofits of medium‑size cargo and offshore vessels to improve port manoeuvring, especially where dry‑dock windows are limited. The IWSS seal makes it popular for ships operating in harsh environments where underwater maintenance without removing the thruster is advantageous.
Manufacturer Datasheet
Datasheet
Wärtsilä Wärtsilä CT200
Wärtsilä CT200
· 200.0 kW · tunnel steerable thruster
Series
CT
Power (kW)
200
Tunnel diameter (mm)
1100
Type
tunnel
Technical Specifications
Leistungsbereich WST
700 kW bis 4900 kW
Leistungsbereich WTT
400 kW bis 5500 kW
Leistungsbereich WST-R
750 kW bis 6500 kW
Neigungswinkel (WST-R)
8-Grad Propeller-Getriebe-Neigung für 15-20% höheren Schub
Drehbereich
360° kontinuierliche Lenkung in horizontaler Ebene
Wartungsintervalle
5-year inspections, 10-year overhauls or after 40,000–56,000 operating hours
Dichtungstechnologie
Sternguard In-Water Serviceable Seal (IWSS) - vollständig unter Wasser wartbar
Ölsystem
Integrierte Hydraulik mit Feinfiltration zur Lagerverlängerung
Product Lines
  • WST - Steerable Thrusters (700-4900 kW)
  • WTT - Transverse/Tunnel Thrusters (400-5500 kW)
  • WST-R - Retractable Steerable Thrusters (750-6500 kW)
  • WST-E - Electric Steerable Thrusters (WST-18E embedded electric)
  • Underwater-Mountable Steerable Thrusters
Common Failures & Inspection Points
  • Area: Propeller-Blätter: Erosion, Korrosion, Kantenschäden, Verschleißmuster
    Check: Perform visual inspection and NDT (non-destructive testing) according to OEM and classification society standards. Polishing in combination with edge damage repair increases operating efficiency by 2-5%. Check for pitting, erosion patterns and corrosion spots; document severe pitting areas.
  • Area: Propeller blade foot seals: wear, leakage, water ingress
    Check: 5-year overhaul: Disassemble and inspect all seals. 10-year overhaul: Complete replacement of blade foot O-rings. Check for water penetration in jet thruster assembly. Seals are critical for system protection.
  • Area: Wellendichtungen (Shaft Seals): Abnutzung, Leckage, Austauschbedarf
    Check: Measure propeller shaft wear with poker gauge (between last two stern tube seals). Perform complete inspection of tooth clearance, tooth pattern and shaft seals. 5-year overhaul: seal replacement. 10-year overhaul: comprehensive replacement.
  • Area: Bearings (Roller Bearings): wear, bearing clearance, preload, failure symptoms
    Check: 5-year overhaul: Check bearing clearance and wear. 10-year overhaul: Complete bearing replacement, reset preload, perform NDT inspection. Check main bearing axial clearance wear with feeler gauge (0.1 mm); maximum wear limit 2 mm. Use Wärtsilä bearing wear measurement system for remote monitoring of propeller shaft shoulder.
  • Area: Hydrauliksystem: Öl-Verschmutzung (Wasser, Partikel), Filtration, Ölqualität
    Check: Check gear oil regularly. At critical wear limits: partial change (bleed-and-feed) or complete oil change. Monitor water content in oil (critical >1000 ppm). Check fine filtration system and redundant filter options. Continuously filter out water ingress. Use all Wärtsilä-approved spare parts. 5-10-year overhaul: Perform oil change and filter maintenance.
  • Area: Sternguard In-Water Serviceable Seal (IWSS): seal integrity, maintenance possible underwater
    Check: Check for oil leakage at outer seal. Inspect inflatable emergency seal and inner rope guard. Fully serviceable underwater without habitat or discharge. Measure seal gap and wear. Check retrofit compatibility with other seal types. Confirm compatibility with EAL and mineral oils.

Type-universal inspection/service points for Bow/Stern Thrusters (Wärtsilä, Mega-Schwarm 2026-06). Per-model specs not auto-filled.

Strengths
  • Compact 1100 mm tunnel fits medium‑size vessels while delivering high thrust per kW
  • 360° hydraulic steering provides excellent low‑speed maneuverability
  • Sternguard IWSS allows seal inspection/replacement underwater, reducing dry‑dock time
  • Integrated fine filtration prolongs bearing and gear life
  • Standard 5‑year inspection interval aligns with typical class survey cycles
Weaknesses
  • 200 kW power may be insufficient for large tankers or high‑speed vessels requiring higher bollard pull
  • Fixed tunnel diameter limits propeller size, capping maximum thrust
  • Hydraulic system adds complexity and risk of oil contamination if seals fail
  • Initial cost is higher than basic fixed thrusters due to IWSS and steering gear
  • Not certified for ice‑class or extreme low‑temperature operations
Typical Vessels: Handymax bulk carrierProduct tanker (≤30 k DWT)Offshore supply vesselRo‑Ro ferryContainer feeder
Decision Guide: Choose the CT200 when a compact, steerable bow thruster with underwater‑serviceable seals is needed for vessels up to ~30 k DWT and dry‑dock time must be minimised. Avoid it on ships that require higher thrust, ice‑class capability, or where hydraulic maintenance resources are limited.
Use Cases: Port entry/exit assistance, dynamic positioning support on medium‑size offshore vessels, tight‑berth maneuvering in confined harbours, and retrofits where minimizing dry‑dock periods is a priority.
Manufacturer Datasheet
Datasheet
Wärtsilä CT250
· 250.0 kW · Tunnel‑type bow thruster with IWSS
Series
CT
Power (kW)
250
Tunnel diameter (mm)
1200
Type
tunnel
Technical Specifications
Leistungsbereich WST
700 kW bis 4900 kW
Leistungsbereich WTT
400 kW bis 5500 kW
Leistungsbereich WST-R
750 kW bis 6500 kW
Neigungswinkel (WST-R)
8-Grad Propeller-Getriebe-Neigung für 15-20% höheren Schub
Drehbereich
360° kontinuierliche Lenkung in horizontaler Ebene
Wartungsintervalle
5-year inspections, 10-year overhauls or after 40,000–56,000 operating hours
Dichtungstechnologie
Sternguard In-Water Serviceable Seal (IWSS) - vollständig unter Wasser wartbar
Ölsystem
Integrierte Hydraulik mit Feinfiltration zur Lagerverlängerung
Product Lines
  • WST - Steerable Thrusters (700-4900 kW)
  • WTT - Transverse/Tunnel Thrusters (400-5500 kW)
  • WST-R - Retractable Steerable Thrusters (750-6500 kW)
  • WST-E - Electric Steerable Thrusters (WST-18E embedded electric)
  • Underwater-Mountable Steerable Thrusters
Common Failures & Inspection Points
  • Area: Propeller-Blätter: Erosion, Korrosion, Kantenschäden, Verschleißmuster
    Check: Perform visual inspection and NDT (non-destructive testing) according to OEM and classification society standards. Polishing in combination with edge damage repair increases operating efficiency by 2-5%. Check for pitting, erosion patterns and corrosion spots; document severe pitting areas.
  • Area: Propeller blade foot seals: wear, leakage, water ingress
    Check: 5-year overhaul: Disassemble and inspect all seals. 10-year overhaul: Complete replacement of blade foot O-rings. Check for water penetration in jet thruster assembly. Seals are critical for system protection.
  • Area: Wellendichtungen (Shaft Seals): Abnutzung, Leckage, Austauschbedarf
    Check: Measure propeller shaft wear with poker gauge (between last two stern tube seals). Perform complete inspection of tooth clearance, tooth pattern and shaft seals. 5-year overhaul: seal replacement. 10-year overhaul: comprehensive replacement.
  • Area: Bearings (Roller Bearings): wear, bearing clearance, preload, failure symptoms
    Check: 5-year overhaul: Check bearing clearance and wear. 10-year overhaul: Complete bearing replacement, reset preload, perform NDT inspection. Check main bearing axial clearance wear with feeler gauge (0.1 mm); maximum wear limit 2 mm. Use Wärtsilä bearing wear measurement system for remote monitoring of propeller shaft shoulder.
  • Area: Hydrauliksystem: Öl-Verschmutzung (Wasser, Partikel), Filtration, Ölqualität
    Check: Check gear oil regularly. At critical wear limits: partial change (bleed-and-feed) or complete oil change. Monitor water content in oil (critical >1000 ppm). Check fine filtration system and redundant filter options. Continuously filter out water ingress. Use all Wärtsilä-approved spare parts. 5-10-year overhaul: Perform oil change and filter maintenance.
  • Area: Sternguard In-Water Serviceable Seal (IWSS): seal integrity, maintenance possible underwater
    Check: Check for oil leakage at outer seal. Inspect inflatable emergency seal and inner rope guard. Fully serviceable underwater without habitat or discharge. Measure seal gap and wear. Check retrofit compatibility with other seal types. Confirm compatibility with EAL and mineral oils.

Type-universal inspection/service points for Bow/Stern Thrusters (Wärtsilä, Mega-Schwarm 2026-06). Per-model specs not auto-filled.

Strengths
  • Compact 1200 mm tunnel fits vessels with limited hull space
  • High thrust efficiency and 360° continuous steering for precise maneuvering
  • Sternguard In‑Water Serviceable Seal enables underwater maintenance without dry‑docking
  • Integrated hydraulic system with fine filtration extends bearing life
  • DNV‑approved design with a proven service record
Weaknesses
  • Maximum power of 250 kW may be insufficient for large ships or strong cross‑currents
  • Tunnel diameter limits maximum thrust compared to larger WTT models
  • Scheduled 5‑year inspections and 10‑year overhauls increase lifecycle cost
  • Potential cavitation at high RPMs in shallow water conditions
  • Higher upfront cost than simple fixed rudder‑type thrusters
Typical Vessels: Container feederCoastal tankerOffshore supply vessel (OSV)FerryCruise ship tenderDP0/DP1 platform support vessel
Certifications: DNV
Decision Guide: Choose the CT250 when a medium‑size vessel needs high maneuverability in confined ports, DP0/DP1 capability, or the ability to service the thruster underwater without dry‑docking. Avoid it on large bulk carriers, ultra‑large tankers, or any application requiring thrust well above 300 kW.
Use Cases: The CT250 is typically installed on mid‑size vessels that operate in congested harbours or require precise station‑keeping for offshore support tasks. It is common on coastal tankers and container feeders entering tight terminals, on OSVs providing dynamic positioning assistance to rigs, and on ferries where rapid bow‑side thrust improves docking turnaround.
Manufacturer Datasheet
Datasheet
Wärtsilä Wärtsilä WTT-14
Wärtsilä WTT-14
· 300.0 kW · tunnel thruster with underwater‑serviceable seal
Series
WTT
Power (kW)
300
Tunnel diameter (mm)
1400
Type
tunnel
Technical Specifications
Leistungsbereich WST
700 kW bis 4900 kW
Leistungsbereich WTT
400 kW bis 5500 kW
Leistungsbereich WST-R
750 kW bis 6500 kW
Neigungswinkel (WST-R)
8-Grad Propeller-Getriebe-Neigung für 15-20% höheren Schub
Drehbereich
360° kontinuierliche Lenkung in horizontaler Ebene
Wartungsintervalle
5-year inspections, 10-year overhauls or after 40,000–56,000 operating hours
Dichtungstechnologie
Sternguard In-Water Serviceable Seal (IWSS) - vollständig unter Wasser wartbar
Ölsystem
Integrierte Hydraulik mit Feinfiltration zur Lagerverlängerung
Product Lines
  • WST - Steerable Thrusters (700-4900 kW)
  • WTT - Transverse/Tunnel Thrusters (400-5500 kW)
  • WST-R - Retractable Steerable Thrusters (750-6500 kW)
  • WST-E - Electric Steerable Thrusters (WST-18E embedded electric)
  • Underwater-Mountable Steerable Thrusters
Common Failures & Inspection Points
  • Area: Propeller-Blätter: Erosion, Korrosion, Kantenschäden, Verschleißmuster
    Check: Perform visual inspection and NDT (non-destructive testing) according to OEM and classification society standards. Polishing in combination with edge damage repair increases operating efficiency by 2-5%. Check for pitting, erosion patterns and corrosion spots; document severe pitting areas.
  • Area: Propeller blade foot seals: wear, leakage, water ingress
    Check: 5-year overhaul: Disassemble and inspect all seals. 10-year overhaul: Complete replacement of blade foot O-rings. Check for water penetration in jet thruster assembly. Seals are critical for system protection.
  • Area: Wellendichtungen (Shaft Seals): Abnutzung, Leckage, Austauschbedarf
    Check: Measure propeller shaft wear with poker gauge (between last two stern tube seals). Perform complete inspection of tooth clearance, tooth pattern and shaft seals. 5-year overhaul: seal replacement. 10-year overhaul: comprehensive replacement.
  • Area: Bearings (Roller Bearings): wear, bearing clearance, preload, failure symptoms
    Check: 5-year overhaul: Check bearing clearance and wear. 10-year overhaul: Complete bearing replacement, reset preload, perform NDT inspection. Check main bearing axial clearance wear with feeler gauge (0.1 mm); maximum wear limit 2 mm. Use Wärtsilä bearing wear measurement system for remote monitoring of propeller shaft shoulder.
  • Area: Hydrauliksystem: Öl-Verschmutzung (Wasser, Partikel), Filtration, Ölqualität
    Check: Check gear oil regularly. At critical wear limits: partial change (bleed-and-feed) or complete oil change. Monitor water content in oil (critical >1000 ppm). Check fine filtration system and redundant filter options. Continuously filter out water ingress. Use all Wärtsilä-approved spare parts. 5-10-year overhaul: Perform oil change and filter maintenance.
  • Area: Sternguard In-Water Serviceable Seal (IWSS): seal integrity, maintenance possible underwater
    Check: Check for oil leakage at outer seal. Inspect inflatable emergency seal and inner rope guard. Fully serviceable underwater without habitat or discharge. Measure seal gap and wear. Check retrofit compatibility with other seal types. Confirm compatibility with EAL and mineral oils.

Type-universal inspection/service points for Bow/Stern Thrusters (Wärtsilä, Mega-Schwarm 2026-06). Per-model specs not auto-filled.

Strengths
  • Under‑water serviceable Sternguard IWSS seal eliminates the need to dry‑dock for seal replacement
  • Integrated fine‑filtration hydraulic system extends gear life and reduces oil contamination risk
  • Compact 1.4 m tunnel fits in vessels with limited hull space while still providing adequate low‑speed thrust
  • 360° continuous steering gives precise maneuverability during docking and DP operations
  • Defined maintenance intervals (5‑year inspection, 10‑year overhaul) simplify planning
Weaknesses
  • Maximum power of 300 kW may be insufficient for larger vessels requiring higher bollard pull
  • Tunnel geometry adds hull resistance compared with retractable thrusters, slightly increasing fuel consumption at cruise speed
  • Propeller blades are exposed to erosion and cavitation; regular NDT inspections are required
  • Installation requires a relatively large tunnel opening in the hull structure, limiting retrofit options on some ships
  • Oil quality must be closely monitored (water content > 1000 ppm triggers oil change) adding operational vigilance
Typical Vessels: Coastal container vessels (up to ~30 k DWT)Product tankers and small chemical carriersFerries and Ro‑Ro shipsOffshore supply vesselsWorkboats requiring precise low‑speed handling
Certifications: DNV
Decision Guide: Choose the WTT‑14 if you need a reliable, compact bow thruster for vessels up to ~30 k DWT where under‑water seal maintenance and integrated oil filtration are priorities. Avoid it on large tankers or cruise ships that demand higher thrust levels (> 500 kW) or when hull form optimisation favours retractable thrusters to minimise drag.
Use Cases: The WTT‑14 is commonly installed on coastal cargo ships, product tankers and offshore support vessels for port entry/exit maneuvers, dynamic positioning assistance in confined waters, and emergency thrust backup where quick, precise lateral force is required without the downtime of seal replacement.
Manufacturer Datasheet
Datasheet
Wärtsilä Wärtsilä WTT-18
Wärtsilä WTT-18
· 500.0 kW · tunnel-type transverse thruster
Series
WTT
Power (kW)
500
Tunnel diameter (mm)
1800
Type
tunnel
Technical Specifications
Leistungsbereich WST
700 kW bis 4900 kW
Leistungsbereich WTT
400 kW bis 5500 kW
Leistungsbereich WST-R
750 kW bis 6500 kW
Neigungswinkel (WST-R)
8-Grad Propeller-Getriebe-Neigung für 15-20% höheren Schub
Drehbereich
360° kontinuierliche Lenkung in horizontaler Ebene
Wartungsintervalle
5-year inspections, 10-year overhauls or after 40,000–56,000 operating hours
Dichtungstechnologie
Sternguard In-Water Serviceable Seal (IWSS) - vollständig unter Wasser wartbar
Ölsystem
Integrierte Hydraulik mit Feinfiltration zur Lagerverlängerung
Product Lines
  • WST - Steerable Thrusters (700-4900 kW)
  • WTT - Transverse/Tunnel Thrusters (400-5500 kW)
  • WST-R - Retractable Steerable Thrusters (750-6500 kW)
  • WST-E - Electric Steerable Thrusters (WST-18E embedded electric)
  • Underwater-Mountable Steerable Thrusters
Common Failures & Inspection Points
  • Area: Propeller-Blätter: Erosion, Korrosion, Kantenschäden, Verschleißmuster
    Check: Perform visual inspection and NDT (non-destructive testing) according to OEM and classification society standards. Polishing in combination with edge damage repair increases operating efficiency by 2-5%. Check for pitting, erosion patterns and corrosion spots; document severe pitting areas.
  • Area: Propeller blade foot seals: wear, leakage, water ingress
    Check: 5-year overhaul: Disassemble and inspect all seals. 10-year overhaul: Complete replacement of blade foot O-rings. Check for water penetration in jet thruster assembly. Seals are critical for system protection.
  • Area: Wellendichtungen (Shaft Seals): Abnutzung, Leckage, Austauschbedarf
    Check: Measure propeller shaft wear with poker gauge (between last two stern tube seals). Perform complete inspection of tooth clearance, tooth pattern and shaft seals. 5-year overhaul: seal replacement. 10-year overhaul: comprehensive replacement.
  • Area: Bearings (Roller Bearings): wear, bearing clearance, preload, failure symptoms
    Check: 5-year overhaul: Check bearing clearance and wear. 10-year overhaul: Complete bearing replacement, reset preload, perform NDT inspection. Check main bearing axial clearance wear with feeler gauge (0.1 mm); maximum wear limit 2 mm. Use Wärtsilä bearing wear measurement system for remote monitoring of propeller shaft shoulder.
  • Area: Hydrauliksystem: Öl-Verschmutzung (Wasser, Partikel), Filtration, Ölqualität
    Check: Check gear oil regularly. At critical wear limits: partial change (bleed-and-feed) or complete oil change. Monitor water content in oil (critical >1000 ppm). Check fine filtration system and redundant filter options. Continuously filter out water ingress. Use all Wärtsilä-approved spare parts. 5-10-year overhaul: Perform oil change and filter maintenance.
  • Area: Sternguard In-Water Serviceable Seal (IWSS): seal integrity, maintenance possible underwater
    Check: Check for oil leakage at outer seal. Inspect inflatable emergency seal and inner rope guard. Fully serviceable underwater without habitat or discharge. Measure seal gap and wear. Check retrofit compatibility with other seal types. Confirm compatibility with EAL and mineral oils.

Type-universal inspection/service points for Bow/Stern Thrusters (Wärtsilä, Mega-Schwarm 2026-06). Per-model specs not auto-filled.

Strengths
  • High power density – 500 kW delivered through a relatively compact 1.8 m tunnel.
  • Continuous 360° steering without the need for additional gearboxes.
  • Sternguard In‑Water Serviceable Seal (IWSS) enables underwater maintenance, reducing dry‑dock time.
  • Integrated hydraulic system with fine filtration extends bearing and seal life.
  • Broad series power range (400–5500 kW) allows future upgrades or common spares across the fleet.
Weaknesses
  • Fixed tunnel geometry limits installation on vessels with restricted hull space.
  • Hydraulic oil system adds complexity and contamination risk compared with fully electric thrusters.
  • Maintenance intervals (5‑year inspection, 10‑year overhaul) can be longer than for some modern electric models.
  • Tunnel resistance may slightly reduce overall fuel efficiency at low thrust settings.
  • Not retractable – unsuitable where a retractable thruster is required for speed or hull form considerations.
Typical Vessels: Medium‑size tankersContainer ships (up to 8,000 TEU)Bulk carriers (up to 60,000 dwt)Offshore supply vesselsCruise ships
Certifications: DNV GL class approvalABS classification
Decision Guide: Choose the WTT‑18 when you need a high‑power, continuously steerable bow thruster that can be serviced underwater and fits within a standard hull tunnel. It is ideal for vessels operating in congested ports or requiring frequent low‑speed maneuvers. Avoid if your vessel has limited hull space, prefers an all‑electric solution, or requires a retractable thruster to maintain high cruising speeds.
Use Cases: The WTT‑18 is typically installed on tankers, container ships and bulk carriers for port entry/exit, dynamic positioning assistance, emergency thrust generation, and precise maneuvering in narrow channels or offshore terminals. Its underwater serviceable seal makes it popular on vessels with limited scheduled dry‑dock opportunities.
Manufacturer Datasheet
Datasheet
Wärtsilä Wärtsilä WTT-24
Wärtsilä WTT-24
· 1000.0 kW · Tunnel thruster with IWSS seal
Series
WTT
Power (kW)
1000
Tunnel diameter (mm)
2400
Type
tunnel
Technical Specifications
Leistungsbereich WST
700 kW bis 4900 kW
Leistungsbereich WTT
400 kW bis 5500 kW
Leistungsbereich WST-R
750 kW bis 6500 kW
Neigungswinkel (WST-R)
8-Grad Propeller-Getriebe-Neigung für 15-20% höheren Schub
Drehbereich
360° kontinuierliche Lenkung in horizontaler Ebene
Wartungsintervalle
5-year inspections, 10-year overhauls or after 40,000–56,000 operating hours
Dichtungstechnologie
Sternguard In-Water Serviceable Seal (IWSS) - vollständig unter Wasser wartbar
Ölsystem
Integrierte Hydraulik mit Feinfiltration zur Lagerverlängerung
Product Lines
  • WST - Steerable Thrusters (700-4900 kW)
  • WTT - Transverse/Tunnel Thrusters (400-5500 kW)
  • WST-R - Retractable Steerable Thrusters (750-6500 kW)
  • WST-E - Electric Steerable Thrusters (WST-18E embedded electric)
  • Underwater-Mountable Steerable Thrusters
Common Failures & Inspection Points
  • Area: Propeller-Blätter: Erosion, Korrosion, Kantenschäden, Verschleißmuster
    Check: Perform visual inspection and NDT (non-destructive testing) according to OEM and classification society standards. Polishing in combination with edge damage repair increases operating efficiency by 2-5%. Check for pitting, erosion patterns and corrosion spots; document severe pitting areas.
  • Area: Propeller blade foot seals: wear, leakage, water ingress
    Check: 5-year overhaul: Disassemble and inspect all seals. 10-year overhaul: Complete replacement of blade foot O-rings. Check for water penetration in jet thruster assembly. Seals are critical for system protection.
  • Area: Wellendichtungen (Shaft Seals): Abnutzung, Leckage, Austauschbedarf
    Check: Measure propeller shaft wear with poker gauge (between last two stern tube seals). Perform complete inspection of tooth clearance, tooth pattern and shaft seals. 5-year overhaul: seal replacement. 10-year overhaul: comprehensive replacement.
  • Area: Bearings (Roller Bearings): wear, bearing clearance, preload, failure symptoms
    Check: 5-year overhaul: Check bearing clearance and wear. 10-year overhaul: Complete bearing replacement, reset preload, perform NDT inspection. Check main bearing axial clearance wear with feeler gauge (0.1 mm); maximum wear limit 2 mm. Use Wärtsilä bearing wear measurement system for remote monitoring of propeller shaft shoulder.
  • Area: Hydrauliksystem: Öl-Verschmutzung (Wasser, Partikel), Filtration, Ölqualität
    Check: Check gear oil regularly. At critical wear limits: partial change (bleed-and-feed) or complete oil change. Monitor water content in oil (critical >1000 ppm). Check fine filtration system and redundant filter options. Continuously filter out water ingress. Use all Wärtsilä-approved spare parts. 5-10-year overhaul: Perform oil change and filter maintenance.
  • Area: Sternguard In-Water Serviceable Seal (IWSS): seal integrity, maintenance possible underwater
    Check: Check for oil leakage at outer seal. Inspect inflatable emergency seal and inner rope guard. Fully serviceable underwater without habitat or discharge. Measure seal gap and wear. Check retrofit compatibility with other seal types. Confirm compatibility with EAL and mineral oils.

Type-universal inspection/service points for Bow/Stern Thrusters (Wärtsilä, Mega-Schwarm 2026-06). Per-model specs not auto-filled.

Strengths
  • High thrust output in a compact tunnel design (1000 kW in a 2.4 m diameter tunnel)
  • 360° continuous steering enables precise maneuvering and DP capability
  • Sternguard In‑Water Serviceable Seal allows inspection/repair without dry‑docking, reducing downtime
  • Integrated hydraulic system with fine filtration extends bearing and gear life
  • Modular installation – can be fitted as bow or stern thruster on new builds or retrofits
Weaknesses
  • Large tunnel diameter consumes significant hull space, limiting applicability to vessels with sufficient beam
  • Higher initial capital cost compared with simpler fixed‑pitch thrusters
  • Requires regular oil quality monitoring and periodic overhauls (5‑year/10‑year) to avoid seal or bearing wear
  • Weight of the unit adds to overall vessel weight and may affect stability calculations
  • Noise and vibration levels are higher than low‑speed electric azimuth thrusters
Typical Vessels: Container shipCrude oil tankerLNG carrierCruise linerOffshore supply vesselRo‑Ro ferry
Decision Guide: Choose the WTT‑24 when a large vessel needs high bow thrust, precise 360° steering and wants to minimise dry‑dock intervals thanks to its underwater serviceable seal. Avoid it on ships with limited hull width or where budget constraints favour lower‑cost fixed thrusters.
Use Cases: The unit is commonly installed on deep‑draft tankers, container vessels and cruise ships for port entry/exit in confined harbours, dynamic positioning during offshore operations, and maneuvering of LNG carriers at terminals where rapid lateral thrust is critical.
Manufacturer Datasheet
Datasheet
Wärtsilä Wärtsilä WTT-30
Wärtsilä WTT-30
· 1500.0 kW · tunnel thruster
Series
WTT
Power (kW)
1500
Tunnel diameter (mm)
3000
Type
tunnel
Technical Specifications
Leistungsbereich WST
700 kW bis 4900 kW
Leistungsbereich WTT
400 kW bis 5500 kW
Leistungsbereich WST-R
750 kW bis 6500 kW
Neigungswinkel (WST-R)
8-Grad Propeller-Getriebe-Neigung für 15-20% höheren Schub
Drehbereich
360° kontinuierliche Lenkung in horizontaler Ebene
Wartungsintervalle
5-year inspections, 10-year overhauls or after 40,000–56,000 operating hours
Dichtungstechnologie
Sternguard In-Water Serviceable Seal (IWSS) - vollständig unter Wasser wartbar
Ölsystem
Integrierte Hydraulik mit Feinfiltration zur Lagerverlängerung
Product Lines
  • WST - Steerable Thrusters (700-4900 kW)
  • WTT - Transverse/Tunnel Thrusters (400-5500 kW)
  • WST-R - Retractable Steerable Thrusters (750-6500 kW)
  • WST-E - Electric Steerable Thrusters (WST-18E embedded electric)
  • Underwater-Mountable Steerable Thrusters
Common Failures & Inspection Points
  • Area: Propeller-Blätter: Erosion, Korrosion, Kantenschäden, Verschleißmuster
    Check: Perform visual inspection and NDT (non-destructive testing) according to OEM and classification society standards. Polishing in combination with edge damage repair increases operating efficiency by 2-5%. Check for pitting, erosion patterns and corrosion spots; document severe pitting areas.
  • Area: Propeller blade foot seals: wear, leakage, water ingress
    Check: 5-year overhaul: Disassemble and inspect all seals. 10-year overhaul: Complete replacement of blade foot O-rings. Check for water penetration in jet thruster assembly. Seals are critical for system protection.
  • Area: Wellendichtungen (Shaft Seals): Abnutzung, Leckage, Austauschbedarf
    Check: Measure propeller shaft wear with poker gauge (between last two stern tube seals). Perform complete inspection of tooth clearance, tooth pattern and shaft seals. 5-year overhaul: seal replacement. 10-year overhaul: comprehensive replacement.
  • Area: Bearings (Roller Bearings): wear, bearing clearance, preload, failure symptoms
    Check: 5-year overhaul: Check bearing clearance and wear. 10-year overhaul: Complete bearing replacement, reset preload, perform NDT inspection. Check main bearing axial clearance wear with feeler gauge (0.1 mm); maximum wear limit 2 mm. Use Wärtsilä bearing wear measurement system for remote monitoring of propeller shaft shoulder.
  • Area: Hydrauliksystem: Öl-Verschmutzung (Wasser, Partikel), Filtration, Ölqualität
    Check: Check gear oil regularly. At critical wear limits: partial change (bleed-and-feed) or complete oil change. Monitor water content in oil (critical >1000 ppm). Check fine filtration system and redundant filter options. Continuously filter out water ingress. Use all Wärtsilä-approved spare parts. 5-10-year overhaul: Perform oil change and filter maintenance.
  • Area: Sternguard In-Water Serviceable Seal (IWSS): seal integrity, maintenance possible underwater
    Check: Check for oil leakage at outer seal. Inspect inflatable emergency seal and inner rope guard. Fully serviceable underwater without habitat or discharge. Measure seal gap and wear. Check retrofit compatibility with other seal types. Confirm compatibility with EAL and mineral oils.

Type-universal inspection/service points for Bow/Stern Thrusters (Wärtsilä, Mega-Schwarm 2026-06). Per-model specs not auto-filled.

Strengths
  • 1500 kW thrust suitable for large vessels and DP operations
  • Large 3000 mm tunnel reduces cavitation and improves hydraulic efficiency
  • Sternguard IWSS allows full underwater servicing without dry‑dock
  • 360° continuous steering provides precise maneuverability
  • Integrated hydraulic system with fine filtration extends bearing life
Weaknesses
  • Requires a 3 m diameter hull opening, limiting installation on smaller ships
  • Higher capital cost compared with conventional propeller‑type thrusters
  • Complex seal system demands specialized maintenance expertise
  • Increased weight and tunnel volume can affect cargo space or hull strength
  • Oil contamination monitoring is critical; water ingress >1000 ppm mandates immediate action
Typical Vessels: Container shipCrude oil tankerProduct tankerBulk carrierCruise shipOffshore supply vessel
Decision Guide: Choose if you need high‑power bow thrust for vessels ≥150 m LOA, deep draft, or dynamic positioning and can accommodate a 3 m tunnel; avoid if hull space is limited, budget constraints are tight, or the vessel operates in low‑speed ports where lower‑power thrusters suffice.
Use Cases: Deployed on large tankers and container ships for port entry/exit, tight berth handling, dynamic positioning during offshore support, and maneuvering of cruise vessels in congested harbours.
Manufacturer Datasheet
Datasheet
Wärtsilä Wärtsilä WTT-35
Wärtsilä WTT-35
· 2500.0 kW · Tunnel thruster
Series
WTT
Power (kW)
2500
Tunnel diameter (mm)
3500
Type
tunnel
Technical Specifications
Leistungsbereich WST
700 kW bis 4900 kW
Leistungsbereich WTT
400 kW bis 5500 kW
Leistungsbereich WST-R
750 kW bis 6500 kW
Neigungswinkel (WST-R)
8-Grad Propeller-Getriebe-Neigung für 15-20% höheren Schub
Drehbereich
360° kontinuierliche Lenkung in horizontaler Ebene
Wartungsintervalle
5-year inspections, 10-year overhauls or after 40,000–56,000 operating hours
Dichtungstechnologie
Sternguard In-Water Serviceable Seal (IWSS) - vollständig unter Wasser wartbar
Ölsystem
Integrierte Hydraulik mit Feinfiltration zur Lagerverlängerung
Product Lines
  • WST - Steerable Thrusters (700-4900 kW)
  • WTT - Transverse/Tunnel Thrusters (400-5500 kW)
  • WST-R - Retractable Steerable Thrusters (750-6500 kW)
  • WST-E - Electric Steerable Thrusters (WST-18E embedded electric)
  • Underwater-Mountable Steerable Thrusters
Common Failures & Inspection Points
  • Area: Propeller-Blätter: Erosion, Korrosion, Kantenschäden, Verschleißmuster
    Check: Perform visual inspection and NDT (non-destructive testing) according to OEM and classification society standards. Polishing in combination with edge damage repair increases operating efficiency by 2-5%. Check for pitting, erosion patterns and corrosion spots; document severe pitting areas.
  • Area: Propeller blade foot seals: wear, leakage, water ingress
    Check: 5-year overhaul: Disassemble and inspect all seals. 10-year overhaul: Complete replacement of blade foot O-rings. Check for water penetration in jet thruster assembly. Seals are critical for system protection.
  • Area: Wellendichtungen (Shaft Seals): Abnutzung, Leckage, Austauschbedarf
    Check: Measure propeller shaft wear with poker gauge (between last two stern tube seals). Perform complete inspection of tooth clearance, tooth pattern and shaft seals. 5-year overhaul: seal replacement. 10-year overhaul: comprehensive replacement.
  • Area: Bearings (Roller Bearings): wear, bearing clearance, preload, failure symptoms
    Check: 5-year overhaul: Check bearing clearance and wear. 10-year overhaul: Complete bearing replacement, reset preload, perform NDT inspection. Check main bearing axial clearance wear with feeler gauge (0.1 mm); maximum wear limit 2 mm. Use Wärtsilä bearing wear measurement system for remote monitoring of propeller shaft shoulder.
  • Area: Hydrauliksystem: Öl-Verschmutzung (Wasser, Partikel), Filtration, Ölqualität
    Check: Check gear oil regularly. At critical wear limits: partial change (bleed-and-feed) or complete oil change. Monitor water content in oil (critical >1000 ppm). Check fine filtration system and redundant filter options. Continuously filter out water ingress. Use all Wärtsilä-approved spare parts. 5-10-year overhaul: Perform oil change and filter maintenance.
  • Area: Sternguard In-Water Serviceable Seal (IWSS): seal integrity, maintenance possible underwater
    Check: Check for oil leakage at outer seal. Inspect inflatable emergency seal and inner rope guard. Fully serviceable underwater without habitat or discharge. Measure seal gap and wear. Check retrofit compatibility with other seal types. Confirm compatibility with EAL and mineral oils.

Type-universal inspection/service points for Bow/Stern Thrusters (Wärtsilä, Mega-Schwarm 2026-06). Per-model specs not auto-filled.

Strengths
  • High continuous thrust (up to 2500 kW) suitable for large vessels and DP‑assisted operations
  • Sternguard In‑Water Serviceable Seal (IWSS) allows underwater maintenance without dry‑docking
  • Integrated fine‑filtration hydraulic system extends gear life and reduces oil contamination risk
  • Full 360° azimuth steering provides excellent maneuverability in confined ports
  • Broad power range of the WTT series (400–5500 kW) gives flexibility for future upgrades
Weaknesses
  • Large tunnel diameter requires significant hull penetration, affecting structural design and weight distribution
  • Installation cost is high; requires extensive reinforcement and alignment work
  • Regular 5‑year inspections and 10‑year overhauls add to life‑cycle maintenance expenses
  • Propeller blades are prone to erosion/corrosion in abrasive or sand‑laden waters, demanding frequent NDT checks
  • Space consumption may limit suitability for vessels with narrow beam or limited hull volume
Typical Vessels: Container shipCrude oil tankerLNG carrierCruise linerOffshore supply vessel
Certifications: DNVABS
Decision Guide: Choose the WTT‑35 when you need high thrust and precise azimuth control for large vessels, especially where underwater serviceability (IWSS) can reduce dry‑dock downtime. Avoid it on smaller ships with limited beam or when budget constraints make the extensive installation and maintenance regime prohibitive.
Use Cases: The thruster is typically installed at bow or stern of deep‑draft vessels to aid port entry/exit, dynamic positioning, emergency maneuvering, and low‑speed docking in congested waterways. Its underwater‑serviceable seal makes it popular for ships that require high availability and minimal scheduled dry‑dock periods.
Manufacturer Datasheet
Datasheet
WTT Series (Transverse Tunnel Thruster)
50-4,000 kN thrust · Seawater · Electric transverse tunnel thruster
Type
Tunnel Bow/Stern Thruster (FP/CP)
Size Range
  • WTT-11
  • WTT-14
  • WTT-17
  • WTT-20
  • WTT-25
  • WTT-30
Power range (kW)
  • 200
  • 4000
Drive Type
Electric
Construction
CP propeller, epicyclic gear, steel tunnel
Technical Specifications
Leistungsbereich WST
700 kW bis 4900 kW
Leistungsbereich WTT
400 kW bis 5500 kW
Leistungsbereich WST-R
750 kW bis 6500 kW
Neigungswinkel (WST-R)
8-Grad Propeller-Getriebe-Neigung für 15-20% höheren Schub
Drehbereich
360° kontinuierliche Lenkung in horizontaler Ebene
Wartungsintervalle
5-year inspections, 10-year overhauls or after 40,000–56,000 operating hours
Dichtungstechnologie
Sternguard In-Water Serviceable Seal (IWSS) - vollständig unter Wasser wartbar
Ölsystem
Integrierte Hydraulik mit Feinfiltration zur Lagerverlängerung
Product Lines
  • WST - Steerable Thrusters (700-4900 kW)
  • WTT - Transverse/Tunnel Thrusters (400-5500 kW)
  • WST-R - Retractable Steerable Thrusters (750-6500 kW)
  • WST-E - Electric Steerable Thrusters (WST-18E embedded electric)
  • Underwater-Mountable Steerable Thrusters
Common Failures & Inspection Points
  • Area: Propeller-Blätter: Erosion, Korrosion, Kantenschäden, Verschleißmuster
    Check: Perform visual inspection and NDT (non-destructive testing) according to OEM and classification society standards. Polishing in combination with edge damage repair increases operating efficiency by 2-5%. Check for pitting, erosion patterns and corrosion spots; document severe pitting areas.
  • Area: Propeller blade foot seals: wear, leakage, water ingress
    Check: 5-year overhaul: Disassemble and inspect all seals. 10-year overhaul: Complete replacement of blade foot O-rings. Check for water penetration in jet thruster assembly. Seals are critical for system protection.
  • Area: Wellendichtungen (Shaft Seals): Abnutzung, Leckage, Austauschbedarf
    Check: Measure propeller shaft wear with poker gauge (between last two stern tube seals). Perform complete inspection of tooth clearance, tooth pattern and shaft seals. 5-year overhaul: seal replacement. 10-year overhaul: comprehensive replacement.
  • Area: Bearings (Roller Bearings): wear, bearing clearance, preload, failure symptoms
    Check: 5-year overhaul: Check bearing clearance and wear. 10-year overhaul: Complete bearing replacement, reset preload, perform NDT inspection. Check main bearing axial clearance wear with feeler gauge (0.1 mm); maximum wear limit 2 mm. Use Wärtsilä bearing wear measurement system for remote monitoring of propeller shaft shoulder.
  • Area: Hydrauliksystem: Öl-Verschmutzung (Wasser, Partikel), Filtration, Ölqualität
    Check: Check gear oil regularly. At critical wear limits: partial change (bleed-and-feed) or complete oil change. Monitor water content in oil (critical >1000 ppm). Check fine filtration system and redundant filter options. Continuously filter out water ingress. Use all Wärtsilä-approved spare parts. 5-10-year overhaul: Perform oil change and filter maintenance.
  • Area: Sternguard In-Water Serviceable Seal (IWSS): seal integrity, maintenance possible underwater
    Check: Check for oil leakage at outer seal. Inspect inflatable emergency seal and inner rope guard. Fully serviceable underwater without habitat or discharge. Measure seal gap and wear. Check retrofit compatibility with other seal types. Confirm compatibility with EAL and mineral oils.

Type-universal inspection/service points for Bow/Stern Thrusters (Wärtsilä, Mega-Schwarm 2026-06). Per-model specs not auto-filled.

Service: Gear oil analysis every 1,000 hrs. Propeller inspection at drydock. CP mechanism overhaul every 20,000 hrs. Motor insulation test annually. Tunnel grid inspection at drydock.
Spare Parts: Wärtsilä (ehem. Lips, Drunen, Netherlands). Lead time: 3-6 weeks for standard parts. CP hub components: 8-12 weeks.
Strengths
  • High thrust-to-power ratio across a wide power range (400 kW – 5.5 MW)
  • Sternguard In‑Water Serviceable Seal allows underwater maintenance, reducing dry‑dock time
  • 360° continuous steering provides precise low‑speed maneuvering and DP capability
  • Modular size family (WTT‑11 to WTT‑30) fits a broad spectrum of vessel dimensions
  • Integrated fine‑filtration hydraulic system extends bearing life and reduces oil contamination
Weaknesses
  • Large tunnel diameter consumes significant hull space, limiting use on narrow‑beam ships
  • Higher capital cost compared with fixed bow thrusters or simpler azimuth pods
  • Epicyclic gear requires major overhaul roughly every 20 000 operating hours
  • Requires sophisticated control and monitoring electronics for full 360° operation
  • Installation complexity can increase construction schedule
Typical Vessels: Container ships (≥8,000 TEU)Cruise linersLNG carriersProduct tankersOffshore supply vesselsRo‑Ro ferriesDP2/DP3 offshore support vessels
Certifications: DNV GL ApprovedABS ApprovedLR Approved
Decision Guide: Choose if: you need high thrust for docking or DP, want underwater serviceable seals to minimise dry‑dock, and have sufficient hull width for a tunnel thruster. Avoid if: vessel beam is limited, budget constraints favour simpler fixed thrusters, or you prefer azimuth pod propulsion for combined thrust and steering.
Use Cases: The WTT series is typically installed on large vessels that require precise low‑speed handling in confined ports, dynamic positioning during offshore operations, or rapid turnaround during loading/offloading. Its underwater serviceable seal makes it attractive for ships with long intervals between dry‑docks.
Manufacturer Datasheet
Datasheet

Schottel

13
Schottel STT 170 unverified
· 100.0 kW · tunnel thruster
Series
STT
Power (kW)
100
Type
tunnel
Common Failures & Inspection Points
  • Propeller or blade damage from debris can cause vibration and reduced thrust, noticed during maneuvering
  • Gear or bearing wear can produce abnormal noise, heat or metallic debris in lubricant
  • Seal leakage can allow water ingress or oil loss, seen through header-tank level changes or leakage alarms
  • Motor, converter or hydraulic-drive faults can prevent commanded thrust, seen as trips, low power or unavailable thruster status
  • Control or feedback-sensor faults can cause incorrect direction or pitch/azimuth indication, seen as command mismatch alarms
Service: Inspect drive machinery, lubrication, seals, bearings, propeller condition, control feedback and electrical or hydraulic interfaces. Review oil condition, leakage and vibration trends and verify correct response to bridge commands. Exact wear limits and service settings must follow manufacturer documentation.
Spare Parts: Carry approved seals, filters, sensors, control fuses, selected hydraulic or electrical service parts and other maker-recommended critical spares.
Strengths
  • Compact installation footprint suitable for vessels with limited hull space
  • High thrust‑to‑power ratio typical of Schottel STT series (≈100 kW rating)
  • Robust, low‑maintenance design with proven service record
  • Low vibration and noise levels compared with some propeller‑type thrusters
  • Straightforward integration with existing ship control systems
Weaknesses
  • Fixed thrust direction; cannot rotate like an azimuth unit
  • May generate higher hull penetration loads, requiring reinforced tunnel structure
  • Limited maximum thrust for very large vessels or high DP requirements
  • Potentially louder than ducted‑propeller solutions at full power
  • Installation cost can be higher than simple transverse thrusters
Typical Vessels: Container ships (up to ~30,000 dwt)Bulk carriersProduct tankersOffshore supply vesselsCruise ships and ferries
Decision Guide: Choose the STT 170 when a reliable, compact bow thruster with around 100 kW of power is needed for moderate‑size vessels operating in confined ports or requiring basic DP capability. Avoid it if the vessel demands high thrust levels, full 360° thrust vectoring, or the lowest possible acoustic signature.
Use Cases: Used on ferries, offshore vessels, cruise ships, tugs and merchant ships requiring improved harbor maneuvering or station-keeping capability.
Datasheet
Schottel STT 330 unverified
· 300.0 kW · tunnel thruster
Series
STT
Power (kW)
300
Type
tunnel
Common Failures & Inspection Points
  • Propeller fouling, rope entanglement or blade damage causes vibration, reduced thrust or high drive load
  • Shaft-seal or gearbox leakage causes oil loss, water ingress or low-level alarms
  • Bearing or gear wear causes abnormal noise, vibration or rising temperature
  • Electric motor, converter or hydraulic-drive faults cause reduced thrust, failed starts or protective trips
  • Pitch, steering or control-feedback faults as applicable cause incorrect thrust response, loss of direction control or remote-control alarms
Service: Inspect propeller and tunnel or retractable housing when accessible, seals, gearbox or bearings, lubrication, motor or hydraulic drive and control feedback. Review vibration, oil condition, temperature and thrust response. Test bridge and local control under an approved manoeuvring procedure. Refer to the manufacturer documentation for the exact figure for lubrication, clearance, electrical and wear limits.
Spare Parts: Carry seals, filters, approved lubricant, motor-control or drive spares, feedback sensors and critical hydraulic, steering or electrical components.
Strengths
  • High thrust‑to‑power ratio for its 300 kW rating
  • Compact installation footprint suitable for vessels with limited hull space
  • Robust stainless‑steel housing and proven Schottel flow design minimise vibration and wear
  • Modular construction allows relatively quick installation and replacement of the propeller unit
  • Widely accepted by classification societies, facilitating class approval processes
Weaknesses
  • Thrust output lower than comparable azimuth or pod thrusters of similar power, limiting effectiveness for high‑DP requirements
  • Requires a hull tunnel cut‑out, which can be complex on existing ships and may affect structural integrity if not properly reinforced
  • Maintenance of the tunnel liner and seals can be more frequent than for exposed propeller units
  • Noise and cavitation risk increase if the tunnel geometry is not optimally matched to the vessel’s speed profile
  • Power consumption relatively high for small vessels that could use smaller conventional bow thrusters
Typical Vessels: Container shipBulk carrierTanker (up to ~30,000 dwt)Ro‑Ro ferryOffshore supply vessel
Decision Guide: Choose if: you need a reliable, compact bow thruster for medium‑size cargo or offshore vessels where space is limited and dynamic positioning is not critical. Avoid if: the vessel requires high‑precision DP capability, very low acoustic signature, or you prefer an azimuth pod that provides both thrust and steering without hull penetration.
Use Cases: Harbour manoeuvring, dynamic positioning and low-speed transverse or vectored thrust on merchant, passenger and offshore vessels.
Datasheet
Schottel STT 500 unverified
· 500.0 kW · tunnel thruster with water‑lubricated bearings
Series
STT
Power (kW)
500
Type
tunnel
Common Failures & Inspection Points
  • Propeller fouling, rope entanglement or blade damage causes vibration, reduced thrust or high drive load
  • Shaft-seal or gearbox leakage causes oil loss, water ingress or low-level alarms
  • Bearing or gear wear causes abnormal noise, vibration or rising temperature
  • Electric motor, converter or hydraulic-drive faults cause reduced thrust, failed starts or protective trips
  • Pitch, steering or control-feedback faults as applicable cause incorrect thrust response, loss of direction control or remote-control alarms
Service: Inspect propeller and tunnel or retractable housing when accessible, seals, gearbox or bearings, lubrication, motor or hydraulic drive and control feedback. Review vibration, oil condition, temperature and thrust response. Test bridge and local control under an approved manoeuvring procedure. Refer to the manufacturer documentation for the exact figure for lubrication, clearance, electrical and wear limits.
Spare Parts: Carry seals, filters, approved lubricant, motor-control or drive spares, feedback sensors and critical hydraulic, steering or electrical components.
Strengths
  • High thrust‑to‑power ratio thanks to optimized duct geometry
  • Compact tunnel design fits into limited hull spaces
  • Integrated Schottel control system allows seamless helm coordination
  • Proven reliability on a wide range of commercial vessels
  • Low acoustic signature compared with propeller‑type thrusters
Weaknesses
  • Installation requires significant hull penetration and duct reinforcement
  • Water‑lubricated bearings need regular inspection for wear and corrosion
  • Potential cavitation at high RPMs in shallow water conditions
  • Limited thrust directionality – only transverse force is available
  • Higher upfront cost than basic propeller‑type thrusters
Typical Vessels: Product Tanker (up to ~30 000 dwt)Container Feeder (up to ~2 000 TEU)Offshore Supply VesselCruise Ship (mid‑size)LNG/LPG Carrier (small to medium)
Certifications: DNV Type Approval
Decision Guide: Choose the STT 500 if you need strong transverse thrust in a confined bow space, require integrated control with the ship’s helm, and operate vessels up to mid‑size where manoeuvring precision is critical. Avoid it on very large ships that demand higher total thrust or when hull modifications for a tunnel duct are not feasible.
Use Cases: Harbour manoeuvring, dynamic positioning and low-speed transverse or vectored thrust on merchant, passenger and offshore vessels.
Datasheet
Schottel STT 1000 unverified
· 1000.0 kW · water‑lubricated tunnel thruster
Series
STT
Power (kW)
1000
Type
tunnel
Common Failures & Inspection Points
  • Propeller or blade damage from debris can cause vibration and reduced thrust, noticed during maneuvering
  • Gear or bearing wear can produce abnormal noise, heat or metallic debris in lubricant
  • Seal leakage can allow water ingress or oil loss, seen through header-tank level changes or leakage alarms
  • Motor, converter or hydraulic-drive faults can prevent commanded thrust, seen as trips, low power or unavailable thruster status
  • Control or feedback-sensor faults can cause incorrect direction or pitch/azimuth indication, seen as command mismatch alarms
Service: Inspect drive machinery, lubrication, seals, bearings, propeller condition, control feedback and electrical or hydraulic interfaces. Review oil condition, leakage and vibration trends and verify correct response to bridge commands. Exact wear limits and service settings must follow manufacturer documentation.
Spare Parts: Carry approved seals, filters, sensors, control fuses, selected hydraulic or electrical service parts and other maker-recommended critical spares.
Strengths
  • High thrust‑to‑power ratio (≈1.2–1.4 kN/kW) enabling strong low‑speed maneuvering
  • Compact tunnel design fits within limited hull space while delivering up to ~1300 kN thrust
  • Integrated Schottel control system with DP‑ready interface for precise vectoring
  • Proven reliability on cruise ships, LNG carriers and large container vessels
  • Water‑lubricated bearings reduce oil contamination risk and simplify maintenance
Weaknesses
  • Initial purchase and installation cost higher than basic propeller‑type thrusters
  • Requires careful hull reinforcement and duct integration to avoid vibration and cavitation
  • Maintenance of water‑lubrication system demands regular filtration and monitoring
  • Size and power rating make it unsuitable for small (<5,000 GT) vessels
Typical Vessels: Cruise shipLNG carrierLarge container vesselBulk carrier (>30,000 dwt)Offshore supply vesselFerry
Certifications: IMO Type Approval (D‑2)DNV Classification approval
Decision Guide: Choose if you need high maneuverability for a large vessel operating in confined ports or require DP‑ready thrust control. Avoid if the ship’s size and budget do not justify a 1000 kW thruster, or if hull space cannot accommodate a tunnel installation.
Use Cases: Used on ferries, offshore vessels, cruise ships, tugs and merchant ships requiring improved harbor maneuvering or station-keeping capability.
Datasheet
Schottel STT 1710 unverified
· 1710.0 kW · tunnel thruster
Series
STT
Power (kW)
1710
Type
tunnel
Common Failures & Inspection Points
  • Propeller fouling, rope entanglement or blade damage causes vibration, reduced thrust or high drive load
  • Shaft-seal or gearbox leakage causes oil loss, water ingress or low-level alarms
  • Bearing or gear wear causes abnormal noise, vibration or rising temperature
  • Electric motor, converter or hydraulic-drive faults cause reduced thrust, failed starts or protective trips
  • Pitch, steering or control-feedback faults as applicable cause incorrect thrust response, loss of direction control or remote-control alarms
Service: Inspect propeller and tunnel or retractable housing when accessible, seals, gearbox or bearings, lubrication, motor or hydraulic drive and control feedback. Review vibration, oil condition, temperature and thrust response. Test bridge and local control under an approved manoeuvring procedure. Refer to the manufacturer documentation for the exact figure for lubrication, clearance, electrical and wear limits.
Spare Parts: Carry seals, filters, approved lubricant, motor-control or drive spares, feedback sensors and critical hydraulic, steering or electrical components.
Strengths
  • Very high thrust‑to‑power ratio (≈1 710 kW) suitable for DP and tight‑berth maneuvers
  • Compact tunnel housing minimises hull penetration and frees deck space
  • Low cavitation and vibration thanks to optimized duct geometry
  • Integrated control system with optional variable‑pitch propeller for fine thrust control
  • Proven reliability on cruise ships, LNG carriers and offshore support vessels
Weaknesses
  • High power rating leads to increased fuel consumption when operated continuously
  • Installation requires precise hull cut‑outs and structural reinforcement
  • Maintenance of the tunnel duct can be labour‑intensive compared with external azimuth thrusters
  • Higher upfront cost than smaller conventional bow thrusters
  • Best suited for large vessels; over‑sized for small to medium ships
Typical Vessels: Cruise shipLNG carrierOffshore supply vessel (OSV)FPSOLarge bulk carrierContainer ship (>8 000 TEU)
Certifications: DNVABSLloyd's RegisterIMO Type Approval
Decision Guide: Choose the STT 1710 when a vessel needs high thrust for dynamic positioning or tight‑berth handling, has sufficient hull space for a tunnel installation, and can justify the higher capital cost. Avoid it on smaller vessels where lower‑power thrusters meet manoeuvring requirements or where budget constraints dominate.
Use Cases: Harbour manoeuvring, dynamic positioning and low-speed transverse or vectored thrust on merchant, passenger and offshore vessels.
Datasheet
Schottel STT 2500 unverified
· 2500.0 kW · tunnel thruster
Series
STT
Power (kW)
2500
Type
tunnel
Common Failures & Inspection Points
  • Propeller fouling, rope entanglement or blade damage causes vibration, reduced thrust or high drive load
  • Shaft-seal or gearbox leakage causes oil loss, water ingress or low-level alarms
  • Bearing or gear wear causes abnormal noise, vibration or rising temperature
  • Electric motor, converter or hydraulic-drive faults cause reduced thrust, failed starts or protective trips
  • Pitch, steering or control-feedback faults as applicable cause incorrect thrust response, loss of direction control or remote-control alarms
Service: Inspect propeller and tunnel or retractable housing when accessible, seals, gearbox or bearings, lubrication, motor or hydraulic drive and control feedback. Review vibration, oil condition, temperature and thrust response. Test bridge and local control under an approved manoeuvring procedure. Refer to the manufacturer documentation for the exact figure for lubrication, clearance, electrical and wear limits.
Spare Parts: Carry seals, filters, approved lubricant, motor-control or drive spares, feedback sensors and critical hydraulic, steering or electrical components.
Strengths
  • Very high power rating (≈2500 kW) suitable for large ships requiring strong maneuverability
  • Water‑lubricated bearing system reduces wear and maintenance intervals
  • Compact tunnel design fits into limited bow space while providing high thrust efficiency
  • Low acoustic signature compared with conventional propeller‑type thrusters
  • Proven reliability on DP‑class vessels and cruise liners
Weaknesses
  • Significant hull penetration and structural reinforcement required during installation
  • High electrical power demand may increase ship’s overall energy consumption
  • Initial capital cost is higher than smaller tunnel or azimuth thrusters
  • Cavitation risk at very high propeller speeds, requiring careful operation in shallow water
  • Size and weight limit suitability to larger vessels; not ideal for small coasters
Typical Vessels: Container ships (>30 000 dwt)Cruise linersLNG/LPG carriersVery large crude carriers (VLCC) and tankersBulk carriers (>50 000 t)Offshore supply vessels with DP requirements
Certifications: IMO D‑2 Type ApprovalABS Classification approval
Decision Guide: Choose the STT 2500 when a vessel needs high bow thrust for safe port entry, dynamic positioning or emergency stopping and has sufficient hull space for a tunnel installation. Avoid it on smaller ships, vessels with tight budget constraints, or where an azimuth thruster would provide better all‑directional control.
Use Cases: Harbour manoeuvring, dynamic positioning and low-speed transverse or vectored thrust on merchant, passenger and offshore vessels.
Datasheet
Schottel STT 3500 unverified
· 3500.0 kW · water‑lubricated tunnel thruster
Series
STT
Power (kW)
3500
Type
tunnel
Common Failures & Inspection Points
  • Propeller fouling, rope entanglement or blade damage causes vibration, reduced thrust or high drive load
  • Shaft-seal or gearbox leakage causes oil loss, water ingress or low-level alarms
  • Bearing or gear wear causes abnormal noise, vibration or rising temperature
  • Electric motor, converter or hydraulic-drive faults cause reduced thrust, failed starts or protective trips
  • Pitch, steering or control-feedback faults as applicable cause incorrect thrust response, loss of direction control or remote-control alarms
Service: Inspect propeller and tunnel or retractable housing when accessible, seals, gearbox or bearings, lubrication, motor or hydraulic drive and control feedback. Review vibration, oil condition, temperature and thrust response. Test bridge and local control under an approved manoeuvring procedure. Refer to the manufacturer documentation for the exact figure for lubrication, clearance, electrical and wear limits.
Spare Parts: Carry seals, filters, approved lubricant, motor-control or drive spares, feedback sensors and critical hydraulic, steering or electrical components.
Strengths
  • High thrust‑to‑power ratio suitable for large vessels
  • Compact tunnel layout fits within limited hull space
  • Variable frequency drive provides fine speed control and fuel savings
  • Water‑lubricated bearings reduce wear and extend maintenance intervals
  • Integrated Schottel Control System simplifies operator handling
Weaknesses
  • Requires significant hull penetration; installation is complex
  • High electrical power demand (3 500 kW) necessitates robust supply and cooling systems
  • Tunnel geometry may be limited by draft constraints on shallow‑draft vessels
  • Higher initial capital cost compared with simpler azimuth thrusters of similar power
  • Potential for increased noise/vibration that must be mitigated in passenger ships
Typical Vessels: Cruise shipLNG carrierOffshore supply vesselLarge container shipLarge bulk carrier
Certifications: IMO Type ApprovalDNVABS
Decision Guide: Choose if you need a high‑power, compact thruster for precise maneuvering on large vessels where hull space is limited and integrated control is valued. Avoid if the vessel has shallow draft constraints, limited electrical capacity, or a budget that cannot accommodate the higher upfront cost.
Use Cases: Harbour manoeuvring, dynamic positioning and low-speed transverse or vectored thrust on merchant, passenger and offshore vessels.
Datasheet
Schottel SRP 100 unverified
· 100.0 kW · azimuth bow thruster
Series
SRP
Power (kW)
100
Type
azimuth
Common Failures & Inspection Points
  • Propeller or blade damage from debris can cause vibration and reduced thrust, noticed during maneuvering
  • Gear or bearing wear can produce abnormal noise, heat or metallic debris in lubricant
  • Seal leakage can allow water ingress or oil loss, seen through header-tank level changes or leakage alarms
  • Motor, converter or hydraulic-drive faults can prevent commanded thrust, seen as trips, low power or unavailable thruster status
  • Control or feedback-sensor faults can cause incorrect direction or pitch/azimuth indication, seen as command mismatch alarms
Service: Inspect drive machinery, lubrication, seals, bearings, propeller condition, control feedback and electrical or hydraulic interfaces. Review oil condition, leakage and vibration trends and verify correct response to bridge commands. Exact wear limits and service settings must follow manufacturer documentation.
Spare Parts: Carry approved seals, filters, sensors, control fuses, selected hydraulic or electrical service parts and other maker-recommended critical spares.
Strengths
  • High thrust‑to‑power ratio thanks to the ducted (nozzle) design
  • Full 360° rotation enables excellent low‑speed manoeuvrability and dynamic positioning
  • Compact installation footprint fits vessels with limited hull space
  • Integrated control system simplifies operation and reduces crew workload
  • Low vibration and noise compared with open propeller thrusters
Weaknesses
  • Higher upfront cost than conventional fixed‑pitch bow thrusters of similar power
  • Gearbox and bearing maintenance are more complex and require specialised support
  • Limited absolute thrust for very large vessels; may need multiple units on high‑displacement ships
  • Requires dedicated electrical/hydraulic supply and control infrastructure
  • Noise from gearbox can be noticeable in quiet‑zone operations
Typical Vessels: Offshore Supply Vessel (OSV)Ferry / Ro‑Ro passenger shipCoastal tankerSmall container or bulk carrierWorkboat / DredgerCruise ship tender
Certifications: DNV
Decision Guide: Choose the SRP 100 when you need high manoeuvrability in tight ports, have limited hull space for a bow thruster, and require 360° thrust for dynamic positioning or frequent docking. Avoid it if budget constraints dominate, the vessel requires higher total thrust than a single 100 kW unit can provide, or you prefer a simpler fixed‑pitch system with lower maintenance complexity.
Use Cases: Used on ferries, offshore vessels, cruise ships, tugs and merchant ships requiring improved harbor maneuvering or station-keeping capability.
Datasheet
Schottel SRP 200 unverified
· 200.0 kW · azimuth bow thruster
Series
SRP
Power (kW)
200
Type
azimuth
Common Failures & Inspection Points
  • Propeller or blade damage from debris can cause vibration and reduced thrust, noticed during maneuvering
  • Gear or bearing wear can produce abnormal noise, heat or metallic debris in lubricant
  • Seal leakage can allow water ingress or oil loss, seen through header-tank level changes or leakage alarms
  • Motor, converter or hydraulic-drive faults can prevent commanded thrust, seen as trips, low power or unavailable thruster status
  • Control or feedback-sensor faults can cause incorrect direction or pitch/azimuth indication, seen as command mismatch alarms
Service: Inspect drive machinery, lubrication, seals, bearings, propeller condition, control feedback and electrical or hydraulic interfaces. Review oil condition, leakage and vibration trends and verify correct response to bridge commands. Exact wear limits and service settings must follow manufacturer documentation.
Spare Parts: Carry approved seals, filters, sensors, control fuses, selected hydraulic or electrical service parts and other maker-recommended critical spares.
Strengths
  • High thrust‑to‑power ratio thanks to ducted propeller design
  • Full 360° rotation gives excellent low‑speed manoeuvrability and dynamic positioning capability
  • Compact installation footprint fits vessels with limited hull space
  • Integrated control system allows rapid response and fine thrust modulation
  • Low vibration levels compared with conventional tunnel thrusters of similar power
Weaknesses
  • Maximum output limited to ~200 kW, unsuitable for large ships requiring higher bollard pull
  • Higher initial cost than fixed tunnel thrusters of comparable rating
  • Maintenance involves rotating gear and bearing assemblies that require regular inspection
  • Noise can be noticeable at full power if not fitted with acoustic insulation
  • Requires dedicated hydraulic/electrical supply and control cabling
Typical Vessels: Offshore Supply VesselFerryCoastal Container ShipSmall Crude Oil TankerCruise‑ship Tender
Certifications: IMO D-2
Decision Guide: Choose the SRP 200 when a vessel needs high manoeuvrability in tight ports, has limited hull space for thruster installation, and operates within the 150–200 kW power range. Avoid it on large tankers or bulk carriers that require higher thrust levels or where cost‑sensitive fixed tunnel thrusters are preferred.
Use Cases: Used on ferries, offshore vessels, cruise ships, tugs and merchant ships requiring improved harbor maneuvering or station-keeping capability.
Datasheet
Schottel SRP 340 unverified
· 340.0 kW · azimuthing ducted thruster
Series
SRP
Power (kW)
340
Type
azimuth
Common Failures & Inspection Points
  • Propeller fouling, rope entanglement or blade damage causes vibration, reduced thrust or high drive load
  • Shaft-seal or gearbox leakage causes oil loss, water ingress or low-level alarms
  • Bearing or gear wear causes abnormal noise, vibration or rising temperature
  • Electric motor, converter or hydraulic-drive faults cause reduced thrust, failed starts or protective trips
  • Pitch, steering or control-feedback faults as applicable cause incorrect thrust response, loss of direction control or remote-control alarms
Service: Inspect propeller and tunnel or retractable housing when accessible, seals, gearbox or bearings, lubrication, motor or hydraulic drive and control feedback. Review vibration, oil condition, temperature and thrust response. Test bridge and local control under an approved manoeuvring procedure. Refer to the manufacturer documentation for the exact figure for lubrication, clearance, electrical and wear limits.
Spare Parts: Carry seals, filters, approved lubricant, motor-control or drive spares, feedback sensors and critical hydraulic, steering or electrical components.
Strengths
  • High thrust-to-power ratio thanks to the ducted design
  • Full 360° rotation enables excellent station-keeping and tight‑turning capability
  • Compact installation footprint suitable for space‑constrained hulls
  • Integrated control system compatible with most ship automation platforms
  • Low vibration and noise levels compared with conventional tunnel thrusters
Weaknesses
  • Higher initial cost than fixed tunnel or transverse thrusters
  • Rotating gear and bearing assemblies require regular inspection and specialised maintenance
  • Power rating (340 kW) may be insufficient for large vessels needing higher bollard pull
  • Installation demands dedicated hydraulic/electrical supply and space for the rotating pod
Typical Vessels: Offshore Support VesselFerryCruise Ship (mid‑size)Container FeederSmall Bulk Carrier
Certifications: DNVIMO Type Approval
Decision Guide: Choose if you need high maneuverability in confined ports, have limited hull space for a thruster, or require dynamic positioning support on medium‑size vessels. Avoid if the vessel’s required bollard pull exceeds the thrust capability of a 340 kW unit or if budget constraints make cheaper fixed tunnel thrusters more attractive.
Use Cases: Harbour manoeuvring, dynamic positioning and low-speed transverse or vectored thrust on merchant, passenger and offshore vessels.
Datasheet
Schottel SRP 550 unverified
· 550.0 kW · azimuthing ducted bow thruster
Series
SRP
Power (kW)
550
Type
azimuth
Common Failures & Inspection Points
  • Propeller or blade damage from debris can cause vibration and reduced thrust, noticed during maneuvering
  • Gear or bearing wear can produce abnormal noise, heat or metallic debris in lubricant
  • Seal leakage can allow water ingress or oil loss, seen through header-tank level changes or leakage alarms
  • Motor, converter or hydraulic-drive faults can prevent commanded thrust, seen as trips, low power or unavailable thruster status
  • Control or feedback-sensor faults can cause incorrect direction or pitch/azimuth indication, seen as command mismatch alarms
Service: Inspect drive machinery, lubrication, seals, bearings, propeller condition, control feedback and electrical or hydraulic interfaces. Review oil condition, leakage and vibration trends and verify correct response to bridge commands. Exact wear limits and service settings must follow manufacturer documentation.
Spare Parts: Carry approved seals, filters, sensors, control fuses, selected hydraulic or electrical service parts and other maker-recommended critical spares.
Strengths
  • High thrust‑to‑power ratio enables rapid lateral manoeuvring of large vessels
  • Azimuth capability gives 360° thrust direction for superior docking control
  • Compact, low‑profile design fits tight hull spaces and reduces hydrodynamic drag when not in use
  • Direct‑drive motor reduces vibration and maintenance compared with gear‑driven units
  • Integrated control system compatible with most DP and ship handling consoles
Weaknesses
  • Requires a robust high‑power electrical supply (typically 6.5 kV) and associated cabling
  • Higher upfront cost than fixed‑pitch bow thrusters of similar power
  • Installation is more complex due to the rotating tunnel and sealing requirements
  • Duct and propeller wear demand regular inspection and occasional refurbishment
  • Noise and cavitation can be higher at full power, requiring mitigation on noise‑sensitive vessels
Typical Vessels: Container shipBulk carrierTankerCruise linerOffshore supply vesselLNG/LPG carrierFerry
Certifications: DNV
Decision Guide: Choose if: you need a high‑power bow thruster for vessels >30,000 gt operating in confined ports or requiring DP assistance; space is limited and a compact unit is required. Avoid if: the vessel is small (<10,000 gt), budget constraints dominate, or ultra‑low noise levels are mandatory.
Use Cases: Used on ferries, offshore vessels, cruise ships, tugs and merchant ships requiring improved harbor maneuvering or station-keeping capability.
Datasheet
Schottel SRP 1012 unverified
· 1012.0 kW · azimuth rudder‑propeller thruster
Series
SRP
Power (kW)
1012
Type
azimuth
Common Failures & Inspection Points
  • Propeller fouling, rope entanglement or blade damage causes vibration, reduced thrust or high drive load
  • Shaft-seal or gearbox leakage causes oil loss, water ingress or low-level alarms
  • Bearing or gear wear causes abnormal noise, vibration or rising temperature
  • Electric motor, converter or hydraulic-drive faults cause reduced thrust, failed starts or protective trips
  • Pitch, steering or control-feedback faults as applicable cause incorrect thrust response, loss of direction control or remote-control alarms
Service: Inspect propeller and tunnel or retractable housing when accessible, seals, gearbox or bearings, lubrication, motor or hydraulic drive and control feedback. Review vibration, oil condition, temperature and thrust response. Test bridge and local control under an approved manoeuvring procedure. Refer to the manufacturer documentation for the exact figure for lubrication, clearance, electrical and wear limits.
Spare Parts: Carry seals, filters, approved lubricant, motor-control or drive spares, feedback sensors and critical hydraulic, steering or electrical components.
Strengths
  • Very high thrust‑to‑power ratio (≈1 MW) suitable for large vessels requiring strong low‑speed manoeuvring
  • Compact tunnel footprint compared with conventional tunnel thrusters of similar power
  • Proven Schottel reliability and easy access for routine maintenance on the pod exterior
  • Full 360° azimuth steering enables precise DP control and rapid heading changes
  • Integrated hydraulic steering system reduces installation complexity
Weaknesses
  • Higher initial capital cost than standard fixed‑pitch tunnel thrusters of similar rating
  • Requires a relatively deep hull tunnel; retrofits on shallow‑draft ships can be challenging
  • Hydraulic steering line routing adds to installation time and potential leak points
  • Spare parts inventory is specific to Schottel SRP series, limiting interchangeability with other manufacturers
  • Noise and vibration levels are higher than some low‑speed propeller designs, requiring additional mitigation
Typical Vessels: Offshore Supply Vessel (OSV)DP‑class Platform Support VesselCruise ShipLarge Container Ship (for port maneuvering)LNG Carrier (DP2/DP3)
Certifications: IMO D‑2 Type Approval
Decision Guide: Choose if you need a single, high‑output bow thruster that can deliver DP‑class thrust in a compact tunnel and you value Schottel’s long‑track record for reliability. Avoid if project budget is tight, the vessel has limited hull depth for a deep tunnel, or you prefer an all‑electric drive solution with lower acoustic signature.
Use Cases: Harbour manoeuvring, dynamic positioning and low-speed transverse or vectored thrust on merchant, passenger and offshore vessels.
Datasheet
Schottel SRP 2020 unverified
· 2020.0 kW · azimuth thruster
Series
SRP
Power (kW)
2020
Type
azimuth
Common Failures & Inspection Points
  • Propeller or blade damage from debris can cause vibration and reduced thrust, noticed during maneuvering
  • Gear or bearing wear can produce abnormal noise, heat or metallic debris in lubricant
  • Seal leakage can allow water ingress or oil loss, seen through header-tank level changes or leakage alarms
  • Motor, converter or hydraulic-drive faults can prevent commanded thrust, seen as trips, low power or unavailable thruster status
  • Control or feedback-sensor faults can cause incorrect direction or pitch/azimuth indication, seen as command mismatch alarms
Service: Inspect drive machinery, lubrication, seals, bearings, propeller condition, control feedback and electrical or hydraulic interfaces. Review oil condition, leakage and vibration trends and verify correct response to bridge commands. Exact wear limits and service settings must follow manufacturer documentation.
Spare Parts: Carry approved seals, filters, sensors, control fuses, selected hydraulic or electrical service parts and other maker-recommended critical spares.
Strengths
  • Very high power rating (≈2 MW) suitable for large ships and DP‑controlled vessels
  • Full 360° thrust vectoring gives excellent low‑speed manoeuvrability and station‑keeping
  • Integrated electronic control system with fast response and fault diagnostics
  • Robust ducted‑propeller design reduces cavitation and improves efficiency at high loads
  • Proven Schottel design with long service history in demanding offshore and cruise applications
Weaknesses
  • Large physical size and hull penetration requirements limit use on smaller vessels
  • Higher capital cost and installation complexity compared with conventional fixed thrusters
  • Maintenance intervals are longer due to gear‑box, bearing and seal wear at high power
  • Requires substantial hydraulic/electrical supply infrastructure on board
  • Noise and vibration levels can be higher than low‑power alternatives if not properly isolated
Typical Vessels: Cruise shipLNG carrierOffshore support vesselDP‑class platform supply vesselLarge Ro‑Ro / ferry
Certifications: DNVABS
Decision Guide: Choose if the vessel needs high thrust for docking, dynamic positioning or tight port manoeuvring and can accommodate a large ducted azimuth unit. Avoid on small to medium vessels where lower‑power fixed thrusters are sufficient or when budget/space constraints dominate.
Use Cases: Used on ferries, offshore vessels, cruise ships, tugs and merchant ships requiring improved harbor maneuvering or station-keeping capability.
Datasheet

Veth Propulsion

12
Veth VL-100 unverified
· 100.0 kW · tunnel bow thruster
Series
VL
Power (kW)
100
Type
tunnel
Common Failures & Inspection Points
  • Propeller fouling, rope entanglement or blade damage causes vibration, reduced thrust or high drive load
  • Shaft-seal or gearbox leakage causes oil loss, water ingress or low-level alarms
  • Bearing or gear wear causes abnormal noise, vibration or rising temperature
  • Electric motor, converter or hydraulic-drive faults cause reduced thrust, failed starts or protective trips
  • Pitch, steering or control-feedback faults as applicable cause incorrect thrust response, loss of direction control or remote-control alarms
Service: Inspect propeller and tunnel or retractable housing when accessible, seals, gearbox or bearings, lubrication, motor or hydraulic drive and control feedback. Review vibration, oil condition, temperature and thrust response. Test bridge and local control under an approved manoeuvring procedure. Refer to the manufacturer documentation for the exact figure for lubrication, clearance, electrical and wear limits.
Spare Parts: Carry seals, filters, approved lubricant, motor-control or drive spares, feedback sensors and critical hydraulic, steering or electrical components.
Strengths
  • Compact tunnel installation fits standard bow sections without major hull modifications
  • Proven Veth design with high hydraulic efficiency for its power class
  • Relatively low acoustic signature compared with propeller‑type thrusters
  • Straightforward maintenance access via the tunnel opening
Weaknesses
  • Limited thrust vectoring – only fixed direction, less effective than azimuth units for dynamic positioning
  • Potential cavitation at high RPMs in shallow water conditions
  • Requires hull penetration and internal duct space, adding to construction complexity
  • Higher fuel consumption per unit of thrust compared with newer pod‑type systems
Typical Vessels: Offshore supply vesselPassenger ferryProduct tanker (up to ~30 k DWT)Bulk carrier (medium size)Cruise ship auxiliary
Decision Guide: Choose the VL‑100 when a conventional, cost‑effective bow thruster is needed for vessels up to medium displacement and the hull already accommodates tunnel installations. Avoid it if the vessel requires high maneuverability for DP operations, ultra‑low noise levels, or space constraints that favour azimuth or pod thrusters.
Use Cases: Harbour manoeuvring, dynamic positioning and low-speed transverse or vectored thrust on merchant, passenger and offshore vessels.
Datasheet
Veth VL-200 unverified
· 200.0 kW · tunnel bow thruster
Series
VL
Power (kW)
200
Type
tunnel
Common Failures & Inspection Points
  • Propeller or blade damage from debris can cause vibration and reduced thrust, noticed during maneuvering
  • Gear or bearing wear can produce abnormal noise, heat or metallic debris in lubricant
  • Seal leakage can allow water ingress or oil loss, seen through header-tank level changes or leakage alarms
  • Motor, converter or hydraulic-drive faults can prevent commanded thrust, seen as trips, low power or unavailable thruster status
  • Control or feedback-sensor faults can cause incorrect direction or pitch/azimuth indication, seen as command mismatch alarms
Service: Inspect drive machinery, lubrication, seals, bearings, propeller condition, control feedback and electrical or hydraulic interfaces. Review oil condition, leakage and vibration trends and verify correct response to bridge commands. Exact wear limits and service settings must follow manufacturer documentation.
Spare Parts: Carry approved seals, filters, sensors, control fuses, selected hydraulic or electrical service parts and other maker-recommended critical spares.
Strengths
  • 200 kW power rating matches the thrust needs of vessels up to roughly 30,000 dwt
  • Compact tunnel housing fits standard hull openings without major structural modifications
  • Veth’s duct geometry is optimised for high thrust efficiency and reduced cavitation
Weaknesses
  • Requires a through‑hull tunnel, which involves hull penetration and associated sealing work
  • Maintenance access can be limited because the propeller operates inside the tunnel
  • Less directional flexibility than azimuth or pod thrusters for vessels needing dynamic positioning
Typical Vessels: General cargoContainer feederRo‑RoOffshore supply vesselSmall bulk carrier
Decision Guide: Choose if: you need a cost‑effective, high‑thrust solution for medium‑size ships and have sufficient hull space for a tunnel installation. Avoid if: the vessel requires 360° thrust vectoring, very tight manoeuvring envelopes, or you want to minimise hull penetrations.
Use Cases: Used on ferries, offshore vessels, cruise ships, tugs and merchant ships requiring improved harbor maneuvering or station-keeping capability.
Datasheet
Veth VL-400 unverified
· 400.0 kW · tunnel bow thruster
Series
VL
Power (kW)
400
Type
tunnel
Common Failures & Inspection Points
  • Propeller or blade damage from debris can cause vibration and reduced thrust, noticed during maneuvering
  • Gear or bearing wear can produce abnormal noise, heat or metallic debris in lubricant
  • Seal leakage can allow water ingress or oil loss, seen through header-tank level changes or leakage alarms
  • Motor, converter or hydraulic-drive faults can prevent commanded thrust, seen as trips, low power or unavailable thruster status
  • Control or feedback-sensor faults can cause incorrect direction or pitch/azimuth indication, seen as command mismatch alarms
Service: Inspect drive machinery, lubrication, seals, bearings, propeller condition, control feedback and electrical or hydraulic interfaces. Review oil condition, leakage and vibration trends and verify correct response to bridge commands. Exact wear limits and service settings must follow manufacturer documentation.
Spare Parts: Carry approved seals, filters, sensors, control fuses, selected hydraulic or electrical service parts and other maker-recommended critical spares.
Strengths
  • High thrust output (≈400 kW) suitable for medium‑size vessels requiring strong side force
  • Compact tunnel installation saves deck space compared with azimuth units
  • Proven Veth design with robust steel housing and corrosion‑resistant lining
  • Relatively low acoustic signature, beneficial for passenger or environmentally sensitive ships
Weaknesses
  • Requires sufficient hull volume at the bow to accommodate the tunnel duct
  • Higher power consumption than smaller thrusters; may increase fuel use during frequent manoeuvres
  • Potential cavitation if operated near design limits, especially in shallow water
  • Maintenance access can be limited once installed, requiring dry‑dock periods for major work
Typical Vessels: Container ship (up to ~8 000 TEU)Cruise linerOffshore supply vesselLNG carrier (mid‑size)Ro‑Ro ferry
Decision Guide: Choose if you need strong lateral thrust for tight port entries, have adequate bow hull space for a tunnel duct, and value a proven, low‑noise solution. Avoid if hull geometry limits tunnel installation, power budget is constrained, or an azimuth thruster’s 360° steering capability is required.
Use Cases: Used on ferries, offshore vessels, cruise ships, tugs and merchant ships requiring improved harbor maneuvering or station-keeping capability.
Datasheet
Veth VL-700 unverified
· 700.0 kW · water‑lubricated tunnel thruster
Series
VL
Power (kW)
700
Type
tunnel
Common Failures & Inspection Points
  • Propeller fouling, rope entanglement or blade damage causes vibration, reduced thrust or high drive load
  • Shaft-seal or gearbox leakage causes oil loss, water ingress or low-level alarms
  • Bearing or gear wear causes abnormal noise, vibration or rising temperature
  • Electric motor, converter or hydraulic-drive faults cause reduced thrust, failed starts or protective trips
  • Pitch, steering or control-feedback faults as applicable cause incorrect thrust response, loss of direction control or remote-control alarms
Service: Inspect propeller and tunnel or retractable housing when accessible, seals, gearbox or bearings, lubrication, motor or hydraulic drive and control feedback. Review vibration, oil condition, temperature and thrust response. Test bridge and local control under an approved manoeuvring procedure. Refer to the manufacturer documentation for the exact figure for lubrication, clearance, electrical and wear limits.
Spare Parts: Carry seals, filters, approved lubricant, motor-control or drive spares, feedback sensors and critical hydraulic, steering or electrical components.
Strengths
  • High power output (700 kW) delivering strong maneuvering force
  • Compact tunnel footprint allows installation in relatively narrow hull sections
  • Water‑lubricated bearings reduce friction and improve efficiency
  • Proven design for DP‑enabled vessels with reliable performance
  • Low acoustic signature compared with some propeller‑type thrusters
Weaknesses
  • Large tunnel diameter may still be restrictive on smaller ships or retrofits
  • Requires dedicated hydraulic power unit and associated control systems
  • Higher initial capital cost than lower‑power alternatives
  • Maintenance of water‑lubricated bearings demands regular monitoring of inlet water quality
  • Power consumption is significant, impacting overall fuel efficiency
Typical Vessels: Container shipCrude oil tankerLNG carrierCruise linerOffshore supply vesselBulk carrier (large class)
Decision Guide: Choose if you need a high‑thrust bow thruster for a large vessel with limited hull space and require reliable DP support. Avoid if the ship is small to medium size, budget‑constrained, or cannot accommodate the tunnel diameter without major structural modifications.
Use Cases: Harbour manoeuvring, dynamic positioning and low-speed transverse or vectored thrust on merchant, passenger and offshore vessels.
Datasheet
Veth VL-1200 unverified
· 1200.0 kW · tunnel bow thruster
Series
VL
Power (kW)
1200
Type
tunnel
Common Failures & Inspection Points
  • Propeller fouling, rope entanglement or blade damage causes vibration, reduced thrust or high drive load
  • Shaft-seal or gearbox leakage causes oil loss, water ingress or low-level alarms
  • Bearing or gear wear causes abnormal noise, vibration or rising temperature
  • Electric motor, converter or hydraulic-drive faults cause reduced thrust, failed starts or protective trips
  • Pitch, steering or control-feedback faults as applicable cause incorrect thrust response, loss of direction control or remote-control alarms
Service: Inspect propeller and tunnel or retractable housing when accessible, seals, gearbox or bearings, lubrication, motor or hydraulic drive and control feedback. Review vibration, oil condition, temperature and thrust response. Test bridge and local control under an approved manoeuvring procedure. Refer to the manufacturer documentation for the exact figure for lubrication, clearance, electrical and wear limits.
Spare Parts: Carry seals, filters, approved lubricant, motor-control or drive spares, feedback sensors and critical hydraulic, steering or electrical components.
Strengths
  • Very high power output (~1200 kW) suitable for large ships requiring strong static thrust
  • Efficient water flow through the tunnel design gives good thrust-to-power ratio
  • Proven class approvals (DNV, ABS) ensure compliance with major classification societies
  • Robust stainless‑steel construction provides long service life in harsh marine environments
  • Integrated control system allows precise maneuvering and easy integration with ship automation
Weaknesses
  • Large tunnel footprint requires significant hull space, limiting installation on smaller vessels
  • Higher weight can affect vessel stability and may require additional ballast considerations
  • Maintenance of the tunnel lining and bearings can be labour‑intensive compared to azimuth units
  • Fuel consumption rises sharply when used continuously for dynamic positioning
Typical Vessels: Cruise shipLNG carrierOffshore supply vesselLarge container shipBulk carrierTanker
Certifications: DNVABS
Decision Guide: Choose if the vessel needs high static thrust for safe port entry/exit of large ships, has sufficient hull space for a tunnel thruster, and requires class‑approved equipment with proven reliability. Avoid if the ship relies on dynamic positioning with azimuth thrusters, has limited bow volume, or prioritises weight savings over maximum thrust.
Use Cases: Harbour manoeuvring, dynamic positioning and low-speed transverse or vectored thrust on merchant, passenger and offshore vessels.
Datasheet
Veth VL-2000 unverified
· 2000.0 kW · tunnel bow thruster
Series
VL
Power (kW)
2000
Type
tunnel
Common Failures & Inspection Points
  • Propeller fouling, rope entanglement or blade damage causes vibration, reduced thrust or high drive load
  • Shaft-seal or gearbox leakage causes oil loss, water ingress or low-level alarms
  • Bearing or gear wear causes abnormal noise, vibration or rising temperature
  • Electric motor, converter or hydraulic-drive faults cause reduced thrust, failed starts or protective trips
  • Pitch, steering or control-feedback faults as applicable cause incorrect thrust response, loss of direction control or remote-control alarms
Service: Inspect propeller and tunnel or retractable housing when accessible, seals, gearbox or bearings, lubrication, motor or hydraulic drive and control feedback. Review vibration, oil condition, temperature and thrust response. Test bridge and local control under an approved manoeuvring procedure. Refer to the manufacturer documentation for the exact figure for lubrication, clearance, electrical and wear limits.
Spare Parts: Carry seals, filters, approved lubricant, motor-control or drive spares, feedback sensors and critical hydraulic, steering or electrical components.
Strengths
  • Very high power output (~2000 kW) delivering strong thrust for vessels >80 000 dwt
  • Compact tunnel layout minimises hull penetration and preserves deck space
  • Integrated variable‑frequency drive allows precise thrust control and energy efficiency
  • Robust marine‑grade bearings and sealed motor housing reduce maintenance intervals
  • Compatible with most major classification societies' installation guidelines
Weaknesses
  • Large power rating leads to high electrical demand and may require dedicated generator capacity
  • Tunnel geometry occupies significant hull volume; retrofits can be costly
  • Cavitation risk at very high RPMs if not matched to propeller design
  • Installation requires structural reinforcement of the bow section
  • Noise and vibration levels higher than low‑speed ducted designs, requiring acoustic mitigation
Typical Vessels: Container shipsBulk carriersCruise linersLNG/LPG carriersOffshore supply vessels
Decision Guide: Choose the VL‑2000 if you need maximum bow thrust for large, deep‑draft vessels operating in tight ports or requiring dynamic positioning. Avoid it on smaller ships where hull space and power availability are limited, or when a low‑noise, low‑power thruster is sufficient.
Use Cases: Harbour manoeuvring, dynamic positioning and low-speed transverse or vectored thrust on merchant, passenger and offshore vessels.
Datasheet
Veth VL-4000 unverified
· 4000.0 kW · tunnel bow thruster
Series
VL
Power (kW)
4000
Type
tunnel
Common Failures & Inspection Points
  • Propeller fouling, rope entanglement or blade damage causes vibration, reduced thrust or high drive load
  • Shaft-seal or gearbox leakage causes oil loss, water ingress or low-level alarms
  • Bearing or gear wear causes abnormal noise, vibration or rising temperature
  • Electric motor, converter or hydraulic-drive faults cause reduced thrust, failed starts or protective trips
  • Pitch, steering or control-feedback faults as applicable cause incorrect thrust response, loss of direction control or remote-control alarms
Service: Inspect propeller and tunnel or retractable housing when accessible, seals, gearbox or bearings, lubrication, motor or hydraulic drive and control feedback. Review vibration, oil condition, temperature and thrust response. Test bridge and local control under an approved manoeuvring procedure. Refer to the manufacturer documentation for the exact figure for lubrication, clearance, electrical and wear limits.
Spare Parts: Carry seals, filters, approved lubricant, motor-control or drive spares, feedback sensors and critical hydraulic, steering or electrical components.
Strengths
  • Very high thrust output (~4 MW) suitable for large ships and DP applications
  • Integrated variable‑frequency drive enables fine thrust control
  • Robust, water‑tight tunnel housing tolerates harsh marine environments
  • Low acoustic signature compared with external propeller thrusters
Weaknesses
  • Large hull penetration required; complex installation and alignment
  • High electrical power demand may exceed the capacity of older shipboard generators
  • Significant cooling requirements for continuous high‑power operation
  • Higher procurement and installation cost than lower‑rated thrusters
Typical Vessels: Container ShipCrude Oil TankerLNG CarrierCruise ShipOffshore Support Vessel
Decision Guide: Choose if: the vessel requires >3 MW of bow thrust for safe docking in confined ports, dynamic positioning or emergency manoeuvring on large hulls. Avoid if: the ship’s power plant cannot supply the required electricity, the vessel is under 150 m LOA where a lower‑rated thruster would suffice, or budget constraints limit high‑cost installations.
Use Cases: Harbour manoeuvring, dynamic positioning and low-speed transverse or vectored thrust on merchant, passenger and offshore vessels.
Datasheet
Veth VZ-400 unverified
· 400.0 kW · azimuth bow thruster
Series
VZ
Power (kW)
400
Type
azimuth
Common Failures & Inspection Points
  • Propeller fouling, rope entanglement or blade damage causes vibration, reduced thrust or high drive load
  • Shaft-seal or gearbox leakage causes oil loss, water ingress or low-level alarms
  • Bearing or gear wear causes abnormal noise, vibration or rising temperature
  • Electric motor, converter or hydraulic-drive faults cause reduced thrust, failed starts or protective trips
  • Pitch, steering or control-feedback faults as applicable cause incorrect thrust response, loss of direction control or remote-control alarms
Service: Inspect propeller and tunnel or retractable housing when accessible, seals, gearbox or bearings, lubrication, motor or hydraulic drive and control feedback. Review vibration, oil condition, temperature and thrust response. Test bridge and local control under an approved manoeuvring procedure. Refer to the manufacturer documentation for the exact figure for lubrication, clearance, electrical and wear limits.
Spare Parts: Carry seals, filters, approved lubricant, motor-control or drive spares, feedback sensors and critical hydraulic, steering or electrical components.
Strengths
  • High continuous power (400 kW) delivering strong lateral thrust for large ships
  • Full 360‑degree rotation enables optimal heading control and reduced turning radius
  • Compact tunnel layout compared with conventional fixed‑pitch thrusters, saving hull space
  • Typically integrated with advanced electronic control systems for seamless DP or manual operation
Weaknesses
  • Higher power rating leads to increased fuel consumption and operational cost
  • Installation requires a relatively large tunnel aperture and structural reinforcement
  • Maintenance complexity can be greater than that of simpler fixed‑pitch thrusters
  • Initial procurement price is usually higher than lower‑power alternatives
Typical Vessels: Container ships (≈150 m – 250 m LOA)Bulk carriers and tankers in the 30 kt–35 kt rangeCruise vessels and ferries requiring precise dockingOffshore supply vessels and platform support ships
Decision Guide: Choose if: you need high thrust for a vessel >30,000 gt, require full‑circle steering for tight berthing or DP operations, and have sufficient hull space for a 400 kW tunnel unit. Avoid if: the ship’s power budget is limited, the hull cannot accommodate the required tunnel dimensions, or a lower‑power fixed thruster would meet maneuverability needs.
Use Cases: Harbour manoeuvring, dynamic positioning and low-speed transverse or vectored thrust on merchant, passenger and offshore vessels.
Datasheet
Veth VZ-700 unverified
· 700.0 kW · azimuth bow thruster
Series
VZ
Power (kW)
700
Type
azimuth
Common Failures & Inspection Points
  • Propeller or blade damage from debris can cause vibration and reduced thrust, noticed during maneuvering
  • Gear or bearing wear can produce abnormal noise, heat or metallic debris in lubricant
  • Seal leakage can allow water ingress or oil loss, seen through header-tank level changes or leakage alarms
  • Motor, converter or hydraulic-drive faults can prevent commanded thrust, seen as trips, low power or unavailable thruster status
  • Control or feedback-sensor faults can cause incorrect direction or pitch/azimuth indication, seen as command mismatch alarms
Service: Inspect drive machinery, lubrication, seals, bearings, propeller condition, control feedback and electrical or hydraulic interfaces. Review oil condition, leakage and vibration trends and verify correct response to bridge commands. Exact wear limits and service settings must follow manufacturer documentation.
Spare Parts: Carry approved seals, filters, sensors, control fuses, selected hydraulic or electrical service parts and other maker-recommended critical spares.
Strengths
  • High thrust output suitable for vessels >50,000 dwt
  • Full 360° rotation gives superior manoeuvrability and DP capability
  • Compact tunnel design minimises hull penetration and internal space usage
  • Integrated control electronics compatible with most ship‑bridge systems
  • Proven reliability from Veth’s long‑standing marine thruster heritage
Weaknesses
  • High power rating leads to increased fuel consumption when used continuously
  • Installation may require reinforcement of the bow structure and larger tunnel opening
  • Higher upfront cost compared with conventional fixed‑pitch bow thrusters
  • Maintenance intervals are shorter than low‑power units due to greater mechanical stress
  • Spare parts logistics can be limited in remote ports
Typical Vessels: Container shipCrude oil tankerLNG carrierBulk carrierCruise linerOffshore supply vessel
Certifications: IMO Type Approval (D‑2)ABS ClassificationDNV GL Approval
Decision Guide: Choose if: you need high thrust for large vessels, require precise DP manoeuvring, and have the hull strength to accommodate a 700 kW azimuth unit. Avoid if: vessel size is modest, budget constraints are tight, or the ship’s design cannot support the required tunnel dimensions.
Use Cases: Used on ferries, offshore vessels, cruise ships, tugs and merchant ships requiring improved harbor maneuvering or station-keeping capability.
Datasheet
Veth VZ-1200 unverified
· 1200.0 kW · azimuth bow thruster
Series
VZ
Power (kW)
1200
Type
azimuth
Common Failures & Inspection Points
  • Propeller or blade damage from debris can cause vibration and reduced thrust, noticed during maneuvering
  • Gear or bearing wear can produce abnormal noise, heat or metallic debris in lubricant
  • Seal leakage can allow water ingress or oil loss, seen through header-tank level changes or leakage alarms
  • Motor, converter or hydraulic-drive faults can prevent commanded thrust, seen as trips, low power or unavailable thruster status
  • Control or feedback-sensor faults can cause incorrect direction or pitch/azimuth indication, seen as command mismatch alarms
Service: Inspect drive machinery, lubrication, seals, bearings, propeller condition, control feedback and electrical or hydraulic interfaces. Review oil condition, leakage and vibration trends and verify correct response to bridge commands. Exact wear limits and service settings must follow manufacturer documentation.
Spare Parts: Carry approved seals, filters, sensors, control fuses, selected hydraulic or electrical service parts and other maker-recommended critical spares.
Strengths
  • High thrust output (≈1,200 kW) suitable for large vessels requiring strong lateral force
  • Full 360° rotation enables fine‑scale manoeuvring in confined ports
  • Integrated control system compatible with most DP and bridge consoles
  • Robust hydraulic drive designed for continuous high‑load operation
Weaknesses
  • Significant power demand increases fuel consumption when used extensively
  • Large physical envelope requires substantial hull penetration and space
  • Higher capital cost compared with lower‑power or fixed‑pitch thrusters
  • Maintenance complexity due to hydraulic components and rotating seals
Typical Vessels: Container ship (≥8,000 gt)Cruise linerOffshore supply vesselLNG carrierLarge Ro‑Ro ferry
Decision Guide: Choose if the vessel needs strong bow thrust for tight port entries, dynamic positioning or emergency manoeuvring on ships above ~8,000 gt. Avoid if the ship’s size and operating profile do not justify the high power rating or if budget constraints limit acquisition of a premium azimuth system.
Use Cases: Used on ferries, offshore vessels, cruise ships, tugs and merchant ships requiring improved harbor maneuvering or station-keeping capability.
Datasheet
Veth VZ-2000 unverified
· 2000.0 kW · azimuth bow thruster
Series
VZ
Power (kW)
2000
Type
azimuth
Common Failures & Inspection Points
  • Propeller or blade damage from debris can cause vibration and reduced thrust, noticed during maneuvering
  • Gear or bearing wear can produce abnormal noise, heat or metallic debris in lubricant
  • Seal leakage can allow water ingress or oil loss, seen through header-tank level changes or leakage alarms
  • Motor, converter or hydraulic-drive faults can prevent commanded thrust, seen as trips, low power or unavailable thruster status
  • Control or feedback-sensor faults can cause incorrect direction or pitch/azimuth indication, seen as command mismatch alarms
Service: Inspect drive machinery, lubrication, seals, bearings, propeller condition, control feedback and electrical or hydraulic interfaces. Review oil condition, leakage and vibration trends and verify correct response to bridge commands. Exact wear limits and service settings must follow manufacturer documentation.
Spare Parts: Carry approved seals, filters, sensors, control fuses, selected hydraulic or electrical service parts and other maker-recommended critical spares.
Strengths
  • Very high thrust output (≈2 MW) suitable for large vessels
  • Full 360° thrust direction gives superior maneuverability in tight ports
  • Integrated electronic control system enables seamless DP integration
  • Water‑lubricated bearings reduce vibration and maintenance intervals
  • Designed for continuous operation under heavy load conditions
Weaknesses
  • High electrical power demand requires robust shipboard power supply
  • Large hull penetration and structural reinforcement increase installation cost
  • Requires dedicated cooling system to manage thermal loads
  • Higher upfront capital expense compared with lower‑power thrusters
  • Spare‑part availability may be limited if Veth has a narrow dealer network
Typical Vessels: LNG CarrierCruise ShipOffshore Supply Vessel (OSV)Ultra‑Large Container ShipHeavy‑Lift / Project Cargo Vessel
Decision Guide: Choose if: you need maximum bow thrust for vessels >30 000 gt operating in confined ports or requiring DP capability. Avoid if: the vessel is small to medium size, power budget is limited, or a lower‑cost thruster meets maneuverability requirements.
Use Cases: Used on ferries, offshore vessels, cruise ships, tugs and merchant ships requiring improved harbor maneuvering or station-keeping capability.
Datasheet
Veth VZ-3500 unverified
· 3500.0 kW · azimuth bow thruster
Series
VZ
Power (kW)
3500
Type
azimuth
Common Failures & Inspection Points
  • Propeller or blade damage from debris can cause vibration and reduced thrust, noticed during maneuvering
  • Gear or bearing wear can produce abnormal noise, heat or metallic debris in lubricant
  • Seal leakage can allow water ingress or oil loss, seen through header-tank level changes or leakage alarms
  • Motor, converter or hydraulic-drive faults can prevent commanded thrust, seen as trips, low power or unavailable thruster status
  • Control or feedback-sensor faults can cause incorrect direction or pitch/azimuth indication, seen as command mismatch alarms
Service: Inspect drive machinery, lubrication, seals, bearings, propeller condition, control feedback and electrical or hydraulic interfaces. Review oil condition, leakage and vibration trends and verify correct response to bridge commands. Exact wear limits and service settings must follow manufacturer documentation.
Spare Parts: Carry approved seals, filters, sensors, control fuses, selected hydraulic or electrical service parts and other maker-recommended critical spares.
Strengths
  • Very high power output (3.5 MW) delivering strong thrust for large ships
  • Full 360° azimuth rotation enables excellent manoeuvrability and DP capability
  • Compact, sealed unit designed for harsh marine environments reduces corrosion risk
  • Integrated control electronics allow fast response and fine thrust modulation
Weaknesses
  • High power rating leads to greater fuel consumption and operating cost
  • Large hydraulic/electrical package requires significant hull space and structural reinforcement
  • Initial purchase price is higher than lower‑power conventional tunnel thrusters
  • Spare‑parts logistics may be limited outside Veth’s primary service regions
Typical Vessels: Crude oil tanker (≥30,000 DWT)LNG carrierLarge container shipCruise linerOffshore supply vessel with DP requirements
Decision Guide: Choose the Veth VZ-3500 if you need a very high‑power bow thruster for large vessels that require precise low‑speed handling or dynamic positioning, and you can accommodate its size and power demand. Avoid it on smaller ships where a lower‑power tunnel thruster would be sufficient, or when budget constraints make the higher capital cost prohibitive.
Use Cases: Used on ferries, offshore vessels, cruise ships, tugs and merchant ships requiring improved harbor maneuvering or station-keeping capability.
Datasheet

Rolls-Royce Marine

6
Rolls-Royce TT1100 unverified
· 100.0 kW · tunnel bow thruster
Series
TT
Power (kW)
100
Tunnel diameter (mm)
1100
Type
tunnel
Common Failures & Inspection Points
  • Propeller fouling, rope entanglement or blade damage causes vibration, reduced thrust or high drive load
  • Shaft-seal or gearbox leakage causes oil loss, water ingress or low-level alarms
  • Bearing or gear wear causes abnormal noise, vibration or rising temperature
  • Electric motor, converter or hydraulic-drive faults cause reduced thrust, failed starts or protective trips
  • Pitch, steering or control-feedback faults as applicable cause incorrect thrust response, loss of direction control or remote-control alarms
Service: Inspect propeller and tunnel or retractable housing when accessible, seals, gearbox or bearings, lubrication, motor or hydraulic drive and control feedback. Review vibration, oil condition, temperature and thrust response. Test bridge and local control under an approved manoeuvring procedure. Refer to the manufacturer documentation for the exact figure for lubrication, clearance, electrical and wear limits.
Spare Parts: Carry seals, filters, approved lubricant, motor-control or drive spares, feedback sensors and critical hydraulic, steering or electrical components.
Strengths
  • High thrust per kilowatt thanks to optimized tunnel geometry
  • Integrated variable‑frequency drive for smooth speed control
  • Low acoustic signature and reduced cavitation, beneficial for DP operations
  • Modular construction simplifies installation and maintenance
  • Rolls‑Royce brand reputation for reliability and after‑sales support
Weaknesses
  • Maximum power of 100 kW may be insufficient for large vessels requiring higher bollard pull
  • Tunnel diameter (1.1 m) limits fit in very narrow hull sections
  • Higher upfront cost compared with generic low‑cost thrusters
  • Requires dedicated cooling water system and electrical supply infrastructure
  • Spare‑part lead times can be longer for remote ports
Typical Vessels: Offshore Supply VesselPlatform Support VesselFerrySmall Container Ship (up to ~150 m LOA)Yacht or Luxury Cruiser
Decision Guide: Choose if you need a proven, low‑noise bow thruster with strong thrust efficiency for vessels up to medium size and operate in confined ports or DP scenarios. Avoid if the vessel requires >150 kW of bow thrust, has extremely tight hull space, or budget constraints dominate the selection.
Use Cases: Harbour manoeuvring, dynamic positioning and low-speed transverse or vectored thrust on merchant, passenger and offshore vessels.
Datasheet
Rolls-Royce TT1800 unverified
· 300.0 kW · hydraulic tunnel thruster
Series
TT
Power (kW)
300
Tunnel diameter (mm)
1800
Type
tunnel
Common Failures & Inspection Points
  • Propeller fouling, rope entanglement or blade damage causes vibration, reduced thrust or high drive load
  • Shaft-seal or gearbox leakage causes oil loss, water ingress or low-level alarms
  • Bearing or gear wear causes abnormal noise, vibration or rising temperature
  • Electric motor, converter or hydraulic-drive faults cause reduced thrust, failed starts or protective trips
  • Pitch, steering or control-feedback faults as applicable cause incorrect thrust response, loss of direction control or remote-control alarms
Service: Inspect propeller and tunnel or retractable housing when accessible, seals, gearbox or bearings, lubrication, motor or hydraulic drive and control feedback. Review vibration, oil condition, temperature and thrust response. Test bridge and local control under an approved manoeuvring procedure. Refer to the manufacturer documentation for the exact figure for lubrication, clearance, electrical and wear limits.
Spare Parts: Carry seals, filters, approved lubricant, motor-control or drive spares, feedback sensors and critical hydraulic, steering or electrical components.
Strengths
  • High thrust output (~300 kW) suitable for large vessels and tight berths
  • Large 1800 mm tunnel reduces cavitation and improves efficiency
  • Integrated control system compatible with most bridge consoles
  • Proven reliability from Rolls‑Royce Marine’s long‑standing thruster line
  • Relatively low acoustic signature compared with azimuth units
Weaknesses
  • Large tunnel diameter requires significant hull opening and reinforcement
  • Higher power demand increases fuel consumption of auxiliary generators
  • Installation space may be limited on vessels with narrow beam or shallow draft
  • Initial capital cost is higher than smaller‑diameter thrusters
  • Maintenance access can be more complex due to size
Typical Vessels: Container shipBulk carrierGeneral cargo vesselRo‑Ro ferryOffshore supply vessel
Decision Guide: Choose the TT1800 when a vessel needs high bow thrust for port manoeuvring, dynamic positioning or emergency stopping and can accommodate a 1.8 m tunnel opening. Avoid it on smaller ships, vessels with strict weight/power limits, or where hull geometry cannot support the required tunnel size.
Use Cases: Harbour manoeuvring, dynamic positioning and low-speed transverse or vectored thrust on merchant, passenger and offshore vessels.
Datasheet
Rolls-Royce TT2200 unverified
· 600.0 kW · tunnel‑type bow thruster
Series
TT
Power (kW)
600
Tunnel diameter (mm)
2200
Type
tunnel
Common Failures & Inspection Points
  • Propeller fouling, rope entanglement or blade damage causes vibration, reduced thrust or high drive load
  • Shaft-seal or gearbox leakage causes oil loss, water ingress or low-level alarms
  • Bearing or gear wear causes abnormal noise, vibration or rising temperature
  • Electric motor, converter or hydraulic-drive faults cause reduced thrust, failed starts or protective trips
  • Pitch, steering or control-feedback faults as applicable cause incorrect thrust response, loss of direction control or remote-control alarms
Service: Inspect propeller and tunnel or retractable housing when accessible, seals, gearbox or bearings, lubrication, motor or hydraulic drive and control feedback. Review vibration, oil condition, temperature and thrust response. Test bridge and local control under an approved manoeuvring procedure. Refer to the manufacturer documentation for the exact figure for lubrication, clearance, electrical and wear limits.
Spare Parts: Carry seals, filters, approved lubricant, motor-control or drive spares, feedback sensors and critical hydraulic, steering or electrical components.
Strengths
  • High thrust per kilowatt thanks to the large 2.2 m tunnel diameter
  • Integrated Rolls‑Royce Thruster Control System with real‑time monitoring and DP compatibility
  • Proven reliability on a wide range of commercial vessels, low maintenance intervals
  • Compact installation footprint relative to delivered thrust, suitable for retrofits
  • Low acoustic signature and vibration compared with conventional propeller thrusters
Weaknesses
  • Large tunnel diameter may limit fit in hulls with restricted bow space
  • Higher upfront capital cost than smaller‑diameter competitors
  • Requires a dedicated high‑capacity power supply and cooling system
  • Bearing and seal maintenance can be more involved due to the size of rotating components
Typical Vessels: Container ships (up to ~150 m LOA)Cruise linersOffshore support vessels (OSVs) with DP‑1/DP‑2 capabilityLNG carriers and large tankers requiring enhanced maneuverability
Certifications: DNV GL Type ApprovalABS Classification
Decision Guide: Choose the TT2200 if you need a medium‑power bow thruster that delivers high thrust efficiency, low cavitation, and integrated DP‑ready control on vessels with sufficient bow space. Avoid it when hull geometry cannot accommodate a 2.2 m tunnel or when project budgets are constrained to lower‑cost, smaller‑diameter solutions.
Use Cases: Harbour manoeuvring, dynamic positioning and low-speed transverse or vectored thrust on merchant, passenger and offshore vessels.
Datasheet
Rolls-Royce TT2400 unverified
· 1000.0 kW · tunnel‑type electric bow thruster
Series
TT
Power (kW)
1000
Tunnel diameter (mm)
2400
Type
tunnel
Common Failures & Inspection Points
  • Propeller fouling, rope entanglement or blade damage causes vibration, reduced thrust or high drive load
  • Shaft-seal or gearbox leakage causes oil loss, water ingress or low-level alarms
  • Bearing or gear wear causes abnormal noise, vibration or rising temperature
  • Electric motor, converter or hydraulic-drive faults cause reduced thrust, failed starts or protective trips
  • Pitch, steering or control-feedback faults as applicable cause incorrect thrust response, loss of direction control or remote-control alarms
Service: Inspect propeller and tunnel or retractable housing when accessible, seals, gearbox or bearings, lubrication, motor or hydraulic drive and control feedback. Review vibration, oil condition, temperature and thrust response. Test bridge and local control under an approved manoeuvring procedure. Refer to the manufacturer documentation for the exact figure for lubrication, clearance, electrical and wear limits.
Spare Parts: Carry seals, filters, approved lubricant, motor-control or drive spares, feedback sensors and critical hydraulic, steering or electrical components.
Strengths
  • Very high thrust output (≈1 MW) suitable for mega‑size ships and DP operations
  • Large 2400 mm tunnel diameter gives excellent hydraulic efficiency and reduced cavitation risk
  • Integrated control package with feedback sensors for precise manoeuvring
  • Proven Rolls‑Royce reliability record and global service network
  • Low acoustic signature compared with open‑propeller designs
Weaknesses
  • Large physical envelope limits installation to vessels with sufficient hull space
  • High power rating leads to greater electricity consumption and higher initial cost
  • Maintenance of large bearings and seals can be more demanding
  • Potential for increased vibration if not correctly aligned during installation
  • Requires robust ship‑board power supply (high voltage) and dedicated control system
Typical Vessels: Ultra‑large container shipsCruise linersVLCC / LR2 tankersLarge LNG carriersBulk carriers >150 k DWTOffshore supply & platform support vessels
Certifications: IMO D‑2USCG Type Approval
Decision Guide: Choose if the vessel needs very high bow thrust for port entry, dynamic positioning or tight‑maneuvering situations and has sufficient hull space for a 2.4 m tunnel. Avoid if the ship is size‑restricted, budget‑constrained, or only requires modest manoeuvring power where a smaller thruster would suffice.
Use Cases: Harbour manoeuvring, dynamic positioning and low-speed transverse or vectored thrust on merchant, passenger and offshore vessels.
Datasheet
Rolls-Royce TT3000 unverified
· 2000.0 kW · tunnel thruster
Series
TT
Power (kW)
2000
Tunnel diameter (mm)
3000
Type
tunnel
Common Failures & Inspection Points
  • Propeller or blade damage from debris can cause vibration and reduced thrust, noticed during maneuvering
  • Gear or bearing wear can produce abnormal noise, heat or metallic debris in lubricant
  • Seal leakage can allow water ingress or oil loss, seen through header-tank level changes or leakage alarms
  • Motor, converter or hydraulic-drive faults can prevent commanded thrust, seen as trips, low power or unavailable thruster status
  • Control or feedback-sensor faults can cause incorrect direction or pitch/azimuth indication, seen as command mismatch alarms
Service: Inspect drive machinery, lubrication, seals, bearings, propeller condition, control feedback and electrical or hydraulic interfaces. Review oil condition, leakage and vibration trends and verify correct response to bridge commands. Exact wear limits and service settings must follow manufacturer documentation.
Spare Parts: Carry approved seals, filters, sensors, control fuses, selected hydraulic or electrical service parts and other maker-recommended critical spares.
Strengths
  • 2000 kW power rating provides very high thrust for maneuvering and DP support on large ships
  • Large 3000 mm tunnel reduces cavitation and improves efficiency at low speeds
  • Integrated Rolls‑Royce control system with fault diagnostics simplifies operation and maintenance
  • Modular design allows installation in a range of hull forms, including narrow bow sections
  • Proven reliability record on cruise ships, tankers and offshore vessels
Weaknesses
  • Large tunnel diameter limits applicability to vessels with sufficient bow space
  • Higher capital cost compared with smaller or azimuth thrusters of similar power
  • Installation requires significant hull penetration and structural reinforcement
  • Power consumption at full rating can be substantial, impacting fuel efficiency when used frequently
Typical Vessels: Container shipCrude oil tankerLNG carrierCruise linerOffshore supply vesselFPSO
Certifications: IMO D-2DNVABS
Decision Guide: Choose if: you need very high bow thrust for a large vessel, have sufficient bow space for a 3 m tunnel, and require integrated monitoring/control. Avoid if: the ship is small to medium size, hull geometry cannot accommodate a large tunnel, or budget constraints preclude a premium‑priced thruster.
Use Cases: Used on ferries, offshore vessels, cruise ships, tugs and merchant ships requiring improved harbor maneuvering or station-keeping capability.
Datasheet
Rolls-Royce Azipull AZP100 unverified
· 3000.0 kW · azimuth pull thruster
Power (kW)
3000
Type
azimuth_pull
Common Failures & Inspection Points
  • Propeller fouling, rope entanglement or blade damage causes vibration, reduced thrust or high drive load
  • Shaft-seal or gearbox leakage causes oil loss, water ingress or low-level alarms
  • Bearing or gear wear causes abnormal noise, vibration or rising temperature
  • Electric motor, converter or hydraulic-drive faults cause reduced thrust, failed starts or protective trips
  • Pitch, steering or control-feedback faults as applicable cause incorrect thrust response, loss of direction control or remote-control alarms
Service: Inspect propeller and tunnel or retractable housing when accessible, seals, gearbox or bearings, lubrication, motor or hydraulic drive and control feedback. Review vibration, oil condition, temperature and thrust response. Test bridge and local control under an approved manoeuvring procedure. Refer to the manufacturer documentation for the exact figure for lubrication, clearance, electrical and wear limits.
Spare Parts: Carry seals, filters, approved lubricant, motor-control or drive spares, feedback sensors and critical hydraulic, steering or electrical components.
Strengths
  • High thrust‑to‑power ratio (≈3000 kW) suitable for DP2/DP3 vessels
  • Full 360° azimuth gives excellent manoeuvrability and station‑keeping
  • Pull‑type propeller reduces cavitation and improves efficiency compared with push designs
  • Integrated control package compatible with most ship automation systems
  • Compact hull penetration footprint, freeing internal space
Weaknesses
  • Large power rating demands substantial electrical supply and cooling infrastructure
  • Installation requires precise alignment of the ducted tunnel and bearings
  • Higher initial capital cost than conventional fixed thrusters of similar power
  • Maintenance of high‑speed bearings and seals can be intensive
  • Noise and vibration levels are higher than low‑speed, low‑rpm alternatives
Typical Vessels: Offshore Support Vessels (OSV)FPSO / FSO unitsLNG carriers with DP requirementsCruise ships needing tight port handlingLarge container and tanker vessels equipped for DP2/3
Certifications: IMO Type Approval
Decision Guide: Choose if: you need high thrust for dynamic positioning, have sufficient electrical generation capacity, and require full azimuth control in a compact bow package. Avoid if: the vessel is small or power‑limited, budget constraints preclude premium thruster costs, or a simpler fixed‑direction thruster meets operational needs.
Use Cases: Harbour manoeuvring, dynamic positioning and low-speed transverse or vectored thrust on merchant, passenger and offshore vessels.
Datasheet

ABB

2
ABB / Azipod (Finland/Switzerland) Azipod Series
Azipod Series
1,000-22,000 kW · Seawater · Podded azimuth electric thruster
Type
Podded Azimuth Thruster (Electric Drive)
Size Range
  • Azipod C
  • Azipod CO
  • Azipod VI
  • Azipod XO
  • Azipod XL
Power range (kW)
  • 1000
  • 22000
Drive Type
Electric (permanent magnet or induction motor in pod)
Construction
Pod-mounted electric motor, pulling propeller, 360° steerable
Common Failures & Inspection Points
  • Pod bearing (slewing ring) wear from heavy ice/maneuvering loads
  • Motor stator winding insulation failure from moisture/vibration
  • Propeller shaft seal seawater ingress
  • Steering hydraulic system failure
Service: Slewing bearing inspection every 5 years. Motor insulation monitoring continuous via ABB Ability system. Shaft seal inspection at drydock. Steering system test annually. Complete pod overhaul: requires drydock, major operation.
Spare Parts: ABB Marine (Helsinki, Finland). Highly specialized — lead time 6-16 weeks for major components. ABB service agreement strongly recommended.
Strengths
  • Full 360° steering eliminates the need for separate rudders or multiple conventional thrusters.
  • Integrated permanent‑magnet or induction motor in the pod reduces mechanical losses and vibration.
  • Compact layout frees up hull space; no shaft line, gearbox or stern tunnel required.
  • High thrust‑to‑power ratio enables rapid berthing and DP operations on large vessels.
  • Seamless integration with diesel‑electric, LNG‑electric or hybrid power plants.
Weaknesses
  • Higher upfront capital cost compared with conventional fixed‑pitch bow thrusters.
  • Maintenance is specialised; pod bearing (slewing ring) wear and seal inspections require drydock periods.
  • Sensitivity to heavy ice loads; bearing wear can accelerate in icy conditions.
  • Complex steering hydraulic/electrical system adds potential failure points.
  • Overhaul of the entire pod is a major operation, often limited by dry‑dock availability.
Typical Vessels: Cruise ShipFerryOffshore Supply Vessel (OSV)LNG CarrierIce‑class Passenger Vessel
Certifications: IMO Type ApprovalDNV Class NotationABS Classification
Decision Guide: Choose if: you need superior low‑speed maneuverability, DP capability, or space‑saving propulsion on a vessel with an electric power plant. Avoid if: budget constraints dominate, the ship operates in heavy ice beyond the pod’s rating, or dry‑dock intervals are too infrequent for the required maintenance.
Use Cases: Azipod bow thrusters are commonly installed on large cruise liners and ferries to enable rapid docking without tug assistance, on LNG carriers and OSVs for precise station‑keeping during offshore operations, and on ice‑class passenger vessels where high maneuverability is needed in constrained ports.
Datasheet
ABB Marine ABB Retractable Thruster
ABB Retractable Thruster
· Retractable bow thruster
Model Number
ABB RT (Retractable)
Strengths
  • Thrust can be deployed when needed and fully retracted, reducing hydrodynamic resistance and fuel consumption
  • Compact installation – fits in limited hull space while preserving deck area
  • High thrust‑to‑power ratio with optional electric or hydraulic drive options
  • Suitable for dynamic positioning (DP) systems and tight‑berth manoeuvring
  • Sealed, low‑maintenance design compared with exposed fixed thrusters
Weaknesses
  • Higher upfront cost than a conventional fixed bow thruster
  • Maximum thrust is lower than that of large fixed units of the same diameter
  • Mechanical retraction system adds complexity and requires periodic inspection
  • Requires internal hull volume for the housing, which may be limited on smaller vessels
  • Potential downtime if the retract/extend mechanism fails
Typical Vessels: Offshore support vessel (OSV)Dynamic positioning vesselCruise shipFerryLNG carrier with maneuverability requirements
Certifications: DNV
Decision Guide: Choose if you need high manoeuvring capability while keeping cruising resistance low, have sufficient internal hull space for the retraction housing, and operate vessels that benefit from DP or frequent port calls. Avoid if budget is tight, vessel size limits internal volume, or maximum thrust requirements exceed what a retractable unit can deliver.
Use Cases: Deployed on vessels that require precise low‑speed control for docking in confined ports, dynamic positioning during offshore operations, and where drag reduction improves fuel efficiency on long voyages. Commonly fitted on OSVs, cruise ships, ferries, and DP‑enabled tankers or LNG carriers.
Datasheet

Brunvoll (Norway)

2
Brunvoll (Norway) FU Series (Tunnel Thruster)
FU Series (Tunnel Thruster)
60-3,500 kN thrust · Seawater · Tunnel bow thruster (fixed/controllable pitch)
Type
Tunnel Bow Thruster (Fixed Pitch / Controllable Pitch)
Size Range
  • FU-45
  • FU-55
  • FU-63
  • FU-74
  • FU-80
  • FU-100
  • FU-115
Power range (kW)
  • 250
  • 3500
Drive Type
Electric / Hydraulic
Construction
Bronze propeller, steel tunnel, gear drive
Common Failures & Inspection Points
  • Gear box oil leakage from shaft seal wear after 15,000-20,000 hrs
  • Propeller blade edge erosion from cavitation
  • Hydraulic motor leak on hydraulic-drive variants
  • Electric motor insulation degradation from moisture ingress
Service: Gear oil analysis every 1,000 hrs. Propeller inspection at drydock. Shaft seal inspection every 5 years. Gear box overhaul every 30,000 hrs. Tunnel grid cleaning annually.
Spare Parts: Brunvoll (Molde, Norway). Lead time: 3-6 weeks for standard parts. Propeller blades: 8-12 weeks. Service network: Norway, Singapore, Shanghai, Rotterdam.
Strengths
  • Wide power range from 250 kW to 3500 kW covering many vessel sizes
  • Both electric and hydraulic drive variants provide installation flexibility
  • Bronze propeller gives excellent corrosion resistance and wear life
  • Modular size series (FU‑45 … FU‑115) fits a variety of hull designs
  • Proven reliability with service history dating back to the 1970s
Weaknesses
  • Gearbox shaft seal wear can cause oil leakage after 15,000–20,000 hrs
  • Propeller blade edges are prone to cavitation erosion in high‑thrust use
  • Hydraulic drive versions may develop motor leaks over time
  • Electric motors require strict moisture control to prevent insulation degradation
  • Steel tunnel adds weight and may limit installation on vessels with thin hull sections
Typical Vessels: Container shipCrude oil tankerProduct tankerBulk carrierGeneral cargo vesselOffshore supply vesselCruise ship
Certifications: DNV
Decision Guide: Choose if you need a high‑thrust, low‑speed bow thruster with proven class approval and the option of electric or hydraulic drive, especially on vessels where a steel tunnel can be accommodated. Avoid if space constraints prevent a tunnel installation, if ultra‑low vibration or oil‑free operation is mandatory, or if severe cavitation conditions are expected.
Use Cases: Standard port maneuvering and docking of tankers and container ships; dynamic positioning support on offshore supply vessels and cruise liners; low‑speed thrust for emergency stop or bollard pull assistance.
Datasheet
Brunvoll (Norway) AR/AX Series (Azimuth Thruster)
AR/AX Series (Azimuth Thruster)
100-5,000 kN thrust · Seawater · Azimuth thruster
Type
Azimuth Thruster (Retractable / Fixed)
Size Range
  • AR-63
  • AR-80
  • AX-80
  • AX-100
  • AX-115
Power range (kW)
  • 500
  • 5000
Drive Type
Electric / Diesel-Electric
Construction
Azimuth pod, L/Z-drive gearbox, CP propeller
Common Failures & Inspection Points
  • Azimuth bearing wear from heavy maneuvering
  • Steering hydraulic cylinder seal failure
  • Lower gear unit oil contamination from seawater ingress
  • Propeller shaft seal wear
Service: Azimuth bearing inspection every 5 years. Lower gear unit oil analysis every 500 hrs. Steering system hydraulic pressure test annually. Complete overhaul at drydock.
Spare Parts: Brunvoll Norway. Lead time: 4-8 weeks for standard parts, 12-16 weeks for gear units. Retractable units: more complex servicing.
Strengths
  • Retractable version (AR) reduces hull resistance when not in use, improving fuel efficiency.
  • Wide power range (≈500 kW to 5 000 kW) covers many vessel sizes from offshore support boats to large cruise ships.
  • Electric and diesel‑electric drive options enable integration with hybrid or all‑electric propulsion systems.
  • Compact L/Z‑drive gearbox and controllable‑pitch propeller give high thrust‑to‑power ratios.
  • Proven design lineage since the early 1990s, with extensive field experience in DP applications.
Weaknesses
  • Azimuth bearing wear accelerates under heavy or frequent maneuvering, requiring five‑year inspections.
  • Hydraulic steering cylinders are a known source of seal failures, leading to downtime if not monitored.
  • Lower gear unit oil can become contaminated by seawater ingress if seals deteriorate.
  • Higher upfront cost and more complex maintenance compared with conventional fixed bow thrusters.
  • Spare‑part availability for older model numbers (e.g., AR‑63) may be limited in some regions.
Typical Vessels: Offshore Supply VesselsAnchor Handling Tug Supply (AHTS)Dynamic Positioning vesselsCruise shipsFerriesIce‑class research or supply ships
Certifications: DNV GL Type ApprovalABS Classification
Decision Guide: Choose if the vessel requires high maneuverability, DP capability, or a retractable thruster to minimise drag during transit. Avoid if budget constraints favour a simpler fixed thruster and the operational profile involves low‑speed, low‑maneuvering work where bearing wear would be excessive.
Use Cases: The AR/AX series is typically installed on vessels that need precise station‑keeping – such as offshore wind installation ships, oil‑rig supply boats, or cruise liners docking in tight ports. The retractable AR models are favoured on ships that spend long periods cruising and only need thrust assistance when entering/exiting ports.
Datasheet

Schottel (Germany)

2
Schottel (Germany) SRP Series (Rudder Propeller)
SRP Series (Rudder Propeller)
30-5,000 kN thrust · Seawater · Azimuth Z‑Drive
Type
Azimuth Rudder Propeller (Z-Drive)
Size Range
  • SRP 100
  • SRP 150
  • SRP 200
  • SRP 330
  • SRP 460
  • SRP 550
  • SRP 710
Power range (kW)
  • 100
  • 5000
Drive Type
Diesel-Mechanical / Electric / Diesel-Electric
Construction
Z-drive gearbox, FP propeller, nozzle optional
Common Failures & Inspection Points
  • Z-drive lower bevel gear wear from high-torque maneuvers
  • Propeller shaft seal seawater ingress
  • Steering motor/cylinder failure
  • Upper bevel gear bearing fatigue after 30,000+ hrs
Service: Gear oil analysis every 1,000 hrs. Propeller shaft seal inspection at drydock. Steering system pressure test annually. Complete overhaul every 30,000-40,000 hrs.
Spare Parts: Schottel (Spay am Rhein, Germany). Global service: Germany, Singapore, Houston, Dubai. Lead time: 3-6 weeks for standard parts.
Strengths
  • Full 360° steering eliminates need for separate rudders and improves maneuverability.
  • High thrust efficiency; optional nozzle increases bollard pull for low‑speed operations.
  • Multiple drive options (diesel‑mechanical, electric, diesel‑electric) allow integration with various power systems.
  • Compact installation compared with traditional tunnel thrusters, freeing hull space.
  • Proven track record since the 1960s; widely supported by Schottel service network.
Weaknesses
  • Complex Z‑drive gearbox leads to higher maintenance demands (gear wear, bearing fatigue).
  • Initial capital cost is greater than conventional tunnel thrusters of similar rating.
  • Requires precise alignment and regular oil analysis; dry‑dock inspections are mandatory.
  • Sensitive to debris ingestion; propeller seal failures can cause seawater ingress.
  • Space below the waterline must accommodate the vertical shaft, limiting use on very shallow drafts.
Typical Vessels: Offshore supply vesselsDynamic positioning (DP) shipsCruise linersFerriesContainer ships (large)LNG carriersTugboats
Certifications: DNV‑GL class approvalABS class approvalIMO Type Approval for Z‑Drive propulsion
Decision Guide: Choose if the vessel requires high maneuverability, DP capability, or frequent tight‑berth operations where a tunnel thruster would be insufficient. Avoid if budget constraints favour simpler thrusters, the vessel has very shallow draft, or operating profiles involve low thrust demands only.
Use Cases: The SRP series is typically installed on large offshore and commercial vessels that need precise station‑keeping for drilling support, rapid port entry/exit of cruise ships, ferry docking in confined terminals, and tug assistance where quick directional changes are critical.
Datasheet
Schottel (Germany) STT Series (Transverse Tunnel Thruster)
STT Series (Transverse Tunnel Thruster)
20-2,000 kN thrust · Seawater · Transverse tunnel thruster
Type
Tunnel Bow/Stern Thruster
Size Range
  • STT 70
  • STT 110
  • STT 170
  • STT 330
  • STT 550
Power range (kW)
  • 50
  • 2000
Drive Type
Electric / Hydraulic
Construction
FP propeller, gear drive, steel tunnel
Common Failures & Inspection Points
  • Gear box oil leak from shaft seal wear
  • Electric motor moisture ingress
  • Propeller blade erosion
  • Tunnel grid corrosion/damage from debris
Service: Gear oil analysis every 1,000 hrs. Motor insulation test annually. Propeller inspection at drydock. Tunnel grid inspection at drydock.
Spare Parts: Schottel global network. Lead time: 3-6 weeks.
Strengths
  • Wide size range (STT 70 to STT 550) covering 50–2000 kW, allowing fit on many vessel classes
  • High thrust‑to‑power ratio with low cavitation thanks to the fixed‑pitch propeller design
  • Modular construction – steel tunnel and gear box can be inspected/maintained separately
  • Dual drive options (electric or hydraulic) give flexibility for existing ship power systems
  • Class‑approved and in service since the 1980s, providing a proven reliability record
Weaknesses
  • Gear‑box oil leaks are common if shaft seals wear; requires regular oil analysis every 1 000 h
  • Electric motor moisture ingress can cause insulation failures if not inspected annually
  • Propeller blades are prone to erosion in abrasive or sand‑laden waters, requiring dry‑dock checks
  • Tunnel grid can corrode or be damaged by debris, demanding periodic inspection and cleaning
  • Relatively large tunnel footprint compared with azimuth thrusters, limiting installation on very narrow hulls
Typical Vessels: Container shipBulk carrierProduct tankerCruise linerOffshore supply vesselRo‑Ro ferry
Certifications: DNV GLABSLloyd's RegisterIMO D-2 type approval for bow thrusters
Decision Guide: Choose if: you need a robust, high‑thrust bow thruster for vessels up to 200 m LOA with existing electric or hydraulic power distribution and value proven class approvals. Avoid if: the vessel has severe space constraints, operates in highly abrasive environments where propeller erosion would be excessive, or requires ultra‑fast maneuvering that azimuth pods can deliver more efficiently.
Use Cases: The STT series is typically installed on medium‑size cargo ships and passenger vessels to aid low‑speed docking, undocking and close‑quarter manoeuvring in ports with limited berth space. It is also used on offshore supply vessels where precise station‑keeping during loading/offloading operations is required.
Datasheet

CSSC / Wuxi Marine Equipment (China)

1
BT/RT Series (Tunnel/Azimuth Thruster)
100-3,000 kN thrust · Seawater · Electric tunnel/azimuth thruster
Type
Tunnel / Azimuth Thruster
Size Range
  • BT-100
  • BT-200
  • BT-300
  • RT-150
  • RT-250
Power range (kW)
  • 200
  • 3000
Drive Type
Electric
Construction
Steel tunnel/azimuth pod, FP/CP propeller
Common Failures & Inspection Points
  • Gear quality inconsistency on early production
  • Motor insulation issues from production tolerances
  • Propeller blade quality varies between foundry batches
Service: Standard thruster maintenance. Quality has improved since 2015 but still below European OEMs. CCS-zugelassen, DNV/BV for some models.
Spare Parts: CSSC/Wuxi (China). Very competitive pricing. Lead time: 2-4 weeks China, 6-10 weeks international.
Strengths
  • Competitive unit price compared with European OEMs
  • Wide power range from 200 kW up to 3 MW covering many vessel sizes
  • Available in both fixed‑pitch (FP) and controllable‑pitch (CP) propeller options
  • Local manufacturing in China gives short lead times for Asian shipyards
  • CCS approval and DNV/BV class certification on later models, with quality improvements after 2015
Weaknesses
  • Early production units reported gear‑box material inconsistencies
  • Motor insulation tolerances have caused premature winding failures in some batches
  • Propeller blade dimensions can vary between foundry lots, affecting performance
  • Overall reliability and after‑sales support generally rated lower than European brands
  • Limited documentation on advanced diagnostics; spare parts may have longer delivery outside China
Typical Vessels: Container shipBulk carrierProduct tankerOffshore supply vesselCruise ship
Certifications: CCSDNVBV
Decision Guide: Choose if you need a cost‑effective thruster with a broad power envelope and can accept Chinese‑origin support; especially suitable for new builds in Asian yards or vessels operating primarily in Asia. Avoid if the project requires the highest reliability track record, extensive European class approvals, or if spare‑part logistics from Europe are critical.
Use Cases: Commonly installed as bow thrusters on container and bulk carriers to aid docking, on offshore supply vessels for dynamic positioning, and on cruise ships for precise maneuvering in congested ports.
Datasheet

Kawasaki

1
KBT Series (Tunnel Thruster)
50-3,000 kN thrust · Seawater · Electric tunnel bow thruster
Type
Tunnel Bow Thruster (FP/CP)
Size Range
  • KBT-100
  • KBT-150
  • KBT-200
  • KBT-250
  • KBT-300
Power range (kW)
  • 250
  • 3000
Drive Type
Electric
Construction
CP propeller, planetary gear, steel tunnel
Common Failures & Inspection Points
  • Planetary gear bearing failure
  • CP hub mechanism hydraulic leak
  • Motor insulation degradation
  • Propeller blade cavitation erosion
Service: Standard tunnel thruster maintenance. Gear oil analysis every 1,000 hrs. CP system overhaul every 20,000 hrs.
Spare Parts: Kawasaki Heavy Industries (Kobe, Japan). Lead time: 3-6 weeks Asia, 6-10 weeks elsewhere.
Strengths
  • High thrust‑to‑power ratio across the 250 kW–3 000 kW range
  • Controllable‑pitch propeller provides fine thrust control and reduced vibration
  • Robust steel tunnel construction resists corrosion in harsh marine environments
  • Modular design allows relatively quick replacement of motor, gear or CP hub
  • Long production history (since 1975) gives proven reliability and wide spare‑parts support
Weaknesses
  • Planetary‑gear bearings are a known wear point requiring oil analysis every ~1 000 h
  • CP hub hydraulic system can develop leaks if not inspected regularly
  • Tunnel geometry limits installation to vessels with sufficient hull depth; retrofits can be costly
  • Higher initial capital cost compared with simple fixed‑pitch tunnel thrusters
  • Maintenance is more intensive than azimuth thrusters that have fewer moving parts
Typical Vessels: Container shipBulk carrierCrude oil tankerLNG/LPG carrierOffshore supply vesselCruise shipRo‑Ro ferry
Decision Guide: Choose if the vessel needs high, controllable thrust for docking, undocking or low‑speed maneuvering and has sufficient hull depth to accommodate a steel tunnel; the electric drive also fits emission‑reduction strategies. Avoid if 360° thrust vectoring is required, hull space is limited, or the operator prefers lower‑maintenance azimuth units for dynamic positioning.
Use Cases: KBT thrusters are commonly installed on new builds and retrofits to provide reliable bow assistance during port entry/exit, aid in tight harbor maneuvers, serve as auxiliary thrust for DP‑assisted vessels, and act as emergency backup when main propulsion is unavailable.
Datasheet

Nakashima Propeller (Japan)

1
Nakashima Propeller (Japan) NTT Series (Tunnel Thruster)
NTT Series (Tunnel Thruster)
30-2,000 kN thrust · Seawater · Electric tunnel thruster with fixed‑pitch propeller
Type
Tunnel Bow Thruster (FP)
Size Range
  • NTT-50
  • NTT-100
  • NTT-150
  • NTT-200
Power range (kW)
  • 150
  • 2000
Drive Type
Electric
Construction
FP propeller, gear drive, steel tunnel
Common Failures & Inspection Points
  • Gear bearing wear after 20,000+ hrs
  • Motor moisture ingress
  • Propeller blade erosion
Service: Standard tunnel thruster maintenance. Gear oil analysis every 1,000 hrs. Propeller inspection at drydock.
Spare Parts: Nakashima (Okayama, Japan). Lead time: 3-6 weeks Asia.
Strengths
  • High thrust density across the 150 kW–2 000 kW range, suitable for medium to large vessels
  • Robust steel tunnel construction provides good resistance to impact and corrosion
  • Standardized FP propeller simplifies spare‑part logistics and allows quick blade replacement
  • Electric drive enables integration with vessel power management systems and reduces emissions compared with hydraulic thrusters
Weaknesses
  • Gear bearings have a documented wear limit of ~20,000 hrs, requiring periodic oil analysis and possible overhauls
  • Motor housing is prone to moisture ingress in high‑humidity or salt‑spray environments if seals are not regularly inspected
  • Fixed‑pitch blades can suffer erosion in abrasive water conditions, reducing efficiency over time
Typical Vessels: Container shipBulk carrierGeneral cargo vesselRo‑Ro ferryOffshore supply vessel
Decision Guide: Choose if: you need a proven, high‑thrust electric bow thruster for vessels >150 m LOA with available space for a steel tunnel and can commit to regular gear oil analysis. Avoid if: the vessel operates in highly abrasive or extremely humid environments where blade erosion or motor moisture could become critical without enhanced sealing measures.
Use Cases: The NTT series is commonly installed on new builds and retrofits of medium‑size cargo ships and offshore supply vessels that require reliable low‑speed maneuverability for port entry, docking, and dynamic positioning support. It is favored where electric power availability simplifies integration with existing shipboard electrical distribution.
Datasheet

Side-Power / Sleipner Motor (Norway)

1
Side-Power / Sleipner Motor (Norway) SE/SP Series (Tunnel Thruster)
SE/SP Series (Tunnel Thruster)
5-200 kN thrust · Seawater · Tunnel bow thruster (electric/hydraulic)
Type
Tunnel Bow Thruster (Electric / Hydraulic)
Size Range
  • SE30
  • SE60
  • SE80
  • SE100
  • SE130
  • SE170
  • SP200
Power range (kW)
  • 3
  • 200
Drive Type
Electric (DC/AC) / Hydraulic
Construction
Compact design, composite or steel tunnel, FP propeller
Common Failures & Inspection Points
  • DC motor brush wear (DC variants)
  • Gear oil overheating from extended continuous use (duty cycle limited)
  • Propeller hub corrosion from dissimilar metals
  • Control relay failure
Service: DC motor brush inspection every 500 hrs. Gear oil change every 1,000 hrs. Duty cycle: typically 4 min on / 15 min off on smaller models. Not designed for continuous operation.
Spare Parts: Side-Power/Sleipner (Fredrikstad, Norway). Lead time: 1-3 weeks. Wide dealer network worldwide.
Strengths
  • Modular size range from SE30 to SP200 covering 3–200 kW, allowing fit on many vessel sizes
  • Dual drive options – electric for low emissions and hydraulic for higher torque applications
  • Compact tunnel construction (steel or composite) reduces hull penetration depth
  • Proven design lineage since the mid‑1980s with a simple FP propeller for reliable thrust generation
  • Straightforward maintenance schedule (brush inspection, gear oil change) documented by manufacturer
Weaknesses
  • DC motor brush wear requires regular inspection every 500 h; AC versions avoid this but may need inverter upkeep
  • Limited duty cycle – not intended for continuous operation; overheating of gear oil can occur if exceeded
  • Propeller hub corrosion risk when dissimilar metals are used in the tunnel lining
  • Control relay failures have been reported, necessitating spare parts on board
  • No built‑in redundancy; a single thruster failure reduces manoeuvring capability
Typical Vessels: Container shipsBulk carriersGeneral cargo vesselsFerries and Ro‑Ro shipsOffshore supply vesselsCruise liners (mid‑size)Coastal tankers
Decision Guide: Choose if the vessel needs a compact, medium‑power bow thruster for short‑duration manoeuvring or DP assistance and can operate within the prescribed duty cycle. Prefer electric drive when emissions or noise are concerns. Avoid on ships that require continuous thrust, very high duty cycles, or where corrosion from dissimilar metals cannot be mitigated.
Use Cases: Installed in port entry/exit maneuvers, docking of ferries, dynamic positioning support on offshore supply vessels, and low‑speed turning for container and bulk carriers during berthing operations.
Datasheet

Thrustmaster of Texas (USA)

1
Thrustmaster of Texas (USA) TH Series (Tunnel Thruster)
TH Series (Tunnel Thruster)
50-2,000 kN thrust · Seawater · Hydraulic/electric tunnel thruster
Type
Tunnel Bow/Stern Thruster (Hydraulic / Electric)
Size Range
  • TH-500
  • TH-750
  • TH-1000
  • TH-1500
  • TH-2000
Power range (kW)
  • 200
  • 2000
Drive Type
Hydraulic / Electric
Construction
FP propeller, gear drive, steel tunnel
Common Failures & Inspection Points
  • Hydraulic power pack motor bearing failure
  • Hydraulic hose degradation from heat/age
  • Gear box seal leakage
  • Propeller blade edge erosion
Service: Hydraulic oil analysis every 500 hrs. Gear oil analysis every 1,000 hrs. Hose replacement per manufacturer schedule. Propeller inspection at drydock.
Spare Parts: Thrustmaster of Texas (Houston, TX). Lead time: 2-4 weeks USA, 4-8 weeks international.
Strengths
  • Wide power envelope (200–2000 kW) covering small to very large vessels
  • Modular size family (TH‑500 to TH‑2000) simplifies selection for different hull forms
  • Dual drive options (hydraulic or electric) allow flexibility based on shipboard power architecture
  • Robust steel tunnel and gear‑drive construction provides high durability in harsh marine environments
  • FP propeller design delivers good thrust efficiency and low cavitation
Weaknesses
  • Hydraulic versions prone to bearing wear in the power‑pack motor and hose degradation from heat/age
  • Gearbox seals can leak, requiring regular oil analysis and potential downtime
  • Propeller blade edge erosion demands periodic dry‑dock inspection and possible refurbishment
  • Installation requires significant tunnel cut‑out and structural reinforcement, increasing build cost
  • Spare‑part availability may be limited compared with more widely used OEM thruster families
Typical Vessels: Container shipBulk carrierCrude oil tankerLiquefied gas carrierCruise linerOffshore supply vessel
Decision Guide: Choose if you need high lateral thrust for large vessels, want the option of hydraulic or electric drive, and can accommodate a steel tunnel installation. Avoid if you prioritize minimal maintenance, have strict space constraints, or require a thruster with an established global support network.
Use Cases: The TH Series is typically installed on new builds or major retrofits to provide precise low‑speed maneuvering in confined ports, assist dynamic positioning systems, and reduce reliance on tug assistance during docking and undocking operations.
Datasheet

Veth Propulsion (Netherlands)

1
VZ/VL Series (Z-Drive / L-Drive)
50-3,000 kN thrust · Seawater · Azimuth thruster (Z‑Drive/L‑Drive)
Type
Azimuth Thruster (Z-Drive / L-Drive)
Size Range
  • VZ-400
  • VZ-600
  • VZ-900
  • VL-400
  • VL-600
Power range (kW)
  • 200
  • 3000
Drive Type
Diesel-Mechanical / Electric
Construction
Z-drive or L-drive, FP propeller
Common Failures & Inspection Points
  • Lower gear bearing seawater contamination
  • Steering motor wear from frequent maneuvering
  • Shaft seal degradation
Service: Gear oil analysis every 1,000 hrs. Shaft seal inspection at drydock. Steering system check annually.
Spare Parts: Veth Propulsion (Papendrecht, Netherlands). Lead time: 3-6 weeks.
Strengths
  • Full 360° thrust vectoring gives superior manoeuvrability compared with conventional tunnel thrusters
  • Compact installation footprint, useful where hull space is limited
  • Modular design allows both diesel‑mechanical and electric drive options to match vessel power architecture
  • High thrust‑to‑power ratio across the VZ‑400 to VZ‑900 size range
  • Standardised gear‑oil monitoring intervals (every 1,000 hrs) simplify condition‑based maintenance
Weaknesses
  • Higher initial capital cost and more complex drive train than simple tunnel thrusters
  • Gear bearings are sensitive to seawater contamination; requires strict oil cleanliness control
  • Shaft seal wear is a known failure mode, demanding regular dry‑dock inspection
  • Spare‑part logistics can be challenging for vessels operating in remote regions
  • Steering motor life may be reduced under very frequent maneuvering cycles
Typical Vessels: Offshore supply & anchor handling tug supply (AHTS) vesselsCruise ships and ferriesContainer ships requiring DP‑assisted berthingLNG carriers with tight port manoeuvring constraintsDynamic positioning platforms and drill‑ships
Certifications: DNVABSIMO D‑2
Decision Guide: Choose if: you need precise low‑speed control, DP capability, or limited hull space for a bow thruster; you value modular drive options and proven azimuth performance. Avoid if: budget constraints favour cheaper tunnel thrusters, the vessel operates at very low maneuvering frequency, or spare‑part support in remote ports is uncertain.
Use Cases: The Veth VZ/VL series is typically installed as a bow thruster on offshore support vessels to maintain position during offshore operations, on cruise ships for tight dock manoeuvring, and on container or LNG carriers where DP assistance shortens port stay. Their 360° thrust makes them ideal for vessels that must hold station in strong currents or wind while loading/unloading.
Datasheet

ZF Marine (Germany)

1
ZF Marine (Germany) AT Series (Azimuth Thruster)
AT Series (Azimuth Thruster)
50-2,000 kN thrust · Seawater · L-drive azimuth thruster
Type
Azimuth Thruster (L-Drive)
Size Range
  • AT 3011
  • AT 4111
  • AT 5111
Power range (kW)
  • 200
  • 2000
Drive Type
Diesel-Mechanical
Construction
L-drive gearbox, FP propeller, integrated with ZF gearbox
Common Failures & Inspection Points
  • L-drive lower gear bearing wear
  • Propeller shaft seal seawater ingress
  • Steering hydraulic cylinder seal failure
Service: Gear oil analysis every 1,000 hrs. Shaft seal inspection at drydock. ZF service network for gearbox overhaul.
Spare Parts: ZF Marine (Padova, Italy / Friedrichshafen, Germany). Lead time: 3-6 weeks.
Strengths
  • Compact footprint – combines gearbox and FP propeller in one unit, saving hull space.
  • Wide power range (200 kW–2 000 kW) covering many vessel sizes.
  • High thrust‑to‑power ratio thanks to the L‑drive geometry.
  • Proven reliability with a global ZF service network for over‑haul and spare parts.
  • Modular design allows relatively quick installation and replacement.
Weaknesses
  • L‑drive lower gear bearing wear reported in long‑term service.
  • Propeller shaft seal prone to seawater ingress, requiring regular dry‑dock inspection.
  • Steering hydraulic cylinder seals can fail, leading to loss of azimuth control.
  • Only diesel‑mechanical drive – no electric or hybrid variant available in the AT series.
  • Maintenance intervals (gear oil analysis every 1 000 h) are stricter than some competing electric thrusters.
Typical Vessels: Offshore supply vesselCruise shipContainer shipBulk carrierFerry
Certifications: DNV Type ApprovalABS ClassificationLloyd's Register (LR) Approval
Decision Guide: Choose if you need a compact, high‑thrust bow thruster with proven mechanical reliability and have access to ZF’s service network. Avoid if you prefer an electric or hybrid azimuth drive, want lower seal‑maintenance demands, or operate vessels where weight savings are critical.
Use Cases: Commonly installed on large commercial ships for port entry and docking assistance, on offshore support vessels for dynamic positioning, and on cruise liners/ferries to reduce turnaround time in confined berths.
Datasheet