Voith Schneider Propeller
medium
30 models total
A Voith Schneider Propeller replaces the conventional shaft, screw and rudder with a disc of vertical blades under the hull whose pitch cycles once per revolution, producing thrust in any direction without a gearbox reversal, separate steering gear or bow thruster.
Read more — Voith Schneider Propeller explained ▾
What defines a Voith Schneider Propeller
A Voith Schneider Propeller (VSP) is a vertical-axis cycloidal propulsion unit fitted flush with the ship's bottom. A rotor disc carries four to six vertical blades that orbit around a common axis at a fixed depth of immersion. Each blade's angle of attack is varied continuously through the rotation by an internal kinematic control mechanism, so the resultant thrust vector can be set to any direction through 360 degrees, or reduced to zero, without changing rotor speed or reversing the drive. This is the key difference from an azimuth thruster: an azimuth unit changes thrust direction by slewing the whole housing and propeller around a vertical axis, which takes time and gear travel; a VSP changes direction by resetting the blade pitch pattern, which is close to instantaneous. It is also the reason VSP-fitted vessels rarely carry a separate rudder or bow thruster — the unit already gives full omnidirectional thrust.
Main components
Rotor disc and blades
The rotor sits in a circular opening in the ship's bottom shell, sealed against the hull. Four to six blades of aerofoil section are mounted on vertical kingposts around the disc's circumference; blade number and chord are matched to the required thrust and to noise/vibration targets.
Control gear (eccentric/scotch yoke mechanism)
A displaceable control point inside the rotor sets the pitch cycle for every blade as it passes through its orbit. Moving this control point changes both the direction and the magnitude of thrust; it is normally actuated hydraulically from the bridge or manoeuvring console.
Main drive and bearings
Power arrives from a diesel engine or electric motor through a vertical or bevel-geared main shaft into the rotor housing. Blade root bearings, the main rotor bearing and the control mechanism bearings all run submerged or in an oil-filled casing and depend on intact seals to keep sea water out.
Seals
Rotating shaft seals between the blade roots and the hull opening, and around the main rotor shaft, are the main barrier against water ingress into the gear casing; their condition is the single most common source of unplanned VSP downtime.
Selection and sizing
A VSP is sized on required bollard pull or free-running thrust, rotor diameter, blade number and permissible draft, since the housing protrudes below the flat of bottom and limits under-keel clearance in shallow water. Typical rotor speeds run from roughly 50 to 90 revolutions per minute depending on unit size, with installed power per unit ranging from a few hundred kilowatts on harbour tugs and ferries to several megawatts on large escort tugs, dredgers and some offshore support vessels. Twin-unit installations are common because they give differential thrust for turning without any rudder at all.
| Selection factor | Why it matters |
|---|---|
| Rotor diameter | Sets maximum thrust and draft penetration below baseline |
| Blade count | Trade-off between thrust smoothness and mechanical complexity |
| Vessel draft | Housing depth limits operation in shallow channels and berths |
| Duty profile | Continuous station-keeping duty wears bearings faster than transit duty |
Regulations and class
Because a VSP combines propulsion and steering in one unit, class societies review it under both propulsion machinery and steering gear rules, and most class societies offer a specific notation for cycloidal propulsion. Where the VSP is the vessel's only means of steering, the redundancy philosophy in SOLAS Ch. II-1 for steering gear is applied by assessing the twin-unit arrangement as the redundant path, since a single mechanical rudder is not fitted. Sea trials normally include a dedicated manoeuvring and crash-stop test programme specific to cycloidal units, and class requires periodic survey of the blade bearings, seals and control mechanism at intervals set by the society's rules for propulsion shafting equivalents.
Typical faults
- Seal failure — sea water enters the gear casing, contaminating the lubricating oil and accelerating bearing wear; usually first detected by a rising water content in routine oil sampling.
- Blade bearing wear — increases mechanical backlash in the pitch-setting linkage, producing vibration and a loss of precision in station-keeping and low-speed manoeuvring.
- Control mechanism wear — an imprecise pitch cycle no longer matches the commanded thrust vector, so the vessel drifts off track even though the console shows the correct setting.
- Blade damage from grounding or debris strike — a bent or nicked blade unbalances the thrust pattern, causing vibration and, in serious cases, forcing a reduction to half power until repair.
What to look for in a supplier
- OEM-sourced blade bearings and seals; tolerances on the pitch mechanism are tight enough that non-genuine parts commonly cause premature wear.
- A service network able to inspect and change blades and seals afloat, without drydocking, since diver or cofferdam access is part of the original design intent.
- Documented sea trial and manoeuvring performance data for the specific rotor size and blade configuration ordered.
- Availability of a spare blade and seal kit sized to the installed unit, held either onboard or at a regional depot.
Log seal condition and gear-casing oil water content at every port call: a seal that starts weeping is the earliest and cheapest warning a VSP gives before bearing damage turns a seal job into a full rotor overhaul.
1 manufacturers · 30 models
Voith Schneider
30
VSP 16R/10
unverified
· 1600.0 kW
· cycloidal propeller
Power (kW)
1600
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Instantaneous thrust vectoring enables precise station‑keeping and tight turning circles.
- Compact installation with low draft, suitable for shallow‑water operations.
- High manoeuvring efficiency at low speeds, ideal for tugs and ferries.
- Robust stainless‑steel blades provide good corrosion resistance in marine environments.
Weaknesses
- Lower propulsive efficiency compared with conventional screw propellers at high cruise speeds.
- Complex mechanical arrangement leads to higher initial cost and specialized maintenance requirements.
- Limited maximum power rating restricts use on very large, high‑speed vessels.
- Noise and vibration levels can be higher than a standard propeller if not properly damped.
Typical Vessels:
Harbour tugCoast guard cutterFerry (short‑route)Offshore supply vesselDynamic positioning platform
Decision Guide: Choose if: you need superior low‑speed manoeuvrability, tight turning radius, or DP capability on a vessel with limited draft. Avoid if: the primary mission is high‑speed transit where propulsive efficiency and fuel economy are paramount.
Use Cases: The VSP 16R/10 is commonly installed on harbor tugs for rapid response, short‑route ferries operating in confined ports, offshore supply ships that must hold position beside rigs, and coast guard vessels requiring quick directional changes during rescue operations.
VSP 16R/15
unverified
· 2400.0 kW
· cycloidal propulsion
Power (kW)
2400
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Instantaneous thrust direction change enables exceptional manoeuvrability in confined waters.
- High thrust at low shaft speed (≈200 rpm) reduces wear on downstream gearboxes.
- Compact installation footprint compared with conventional twin‑screw arrangements.
- Good cavitation resistance, suitable for shallow‑draft operations.
- Well suited to dynamic positioning and precise station‑keeping tasks.
Weaknesses
- Higher mechanical complexity leads to increased maintenance requirements.
- Overall propulsive efficiency at higher cruise speeds is lower than a conventional screw propeller.
- Initial capital cost is significantly greater than standard shaft line solutions.
- Spare‑part availability can be limited to specialised suppliers.
- Noise and vibration levels may be higher, requiring additional mitigation measures.
Typical Vessels:
Harbour tugPassenger ferryOffshore supply vesselDP (dynamic positioning) vesselCoastal patrol craft
Decision Guide: Choose if the vessel requires precise low‑speed thrust control, tight turning circles, or dynamic positioning capability. Avoid if primary design drivers are high cruise speed efficiency, minimal upfront cost, or operation in environments where maintenance resources for complex cycloidal gearboxes are limited.
Use Cases: The VSP 16R/15 is commonly installed on harbor tugs for ship‑assist operations, passenger ferries navigating narrow channels, and offshore support vessels that need reliable station‑keeping while conducting subsea work. Its rapid thrust vectoring also makes it attractive for DP‑class workboats operating near offshore platforms.
VSP 16R/20
unverified
· 3200.0 kW
· cycloidal propeller
Power (kW)
3200
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Instantaneous 360° thrust direction control enables exceptional manoeuvrability and station‑keeping.
- High thrust efficiency at low to medium speeds, ideal for tugging and short‑run ferry services.
- Compact installation with a shallow draft, suitable for vessels operating in confined harbours.
- Excellent response for dynamic positioning (DP) and precise docking maneuvers.
Weaknesses
- Complex mechanical arrangement leads to higher acquisition cost and more intensive maintenance compared with conventional screw propellers.
- Peak efficiency drops at higher vessel speeds; not optimal for long‑haul, high‑speed applications.
- Noise and vibration levels can be higher, requiring additional acoustic mitigation measures.
- Spare parts inventory is specialised, potentially increasing downtime if supply chains are limited.
Typical Vessels:
Harbour tugOcean-going tugPassenger ferry (short‑run)Offshore supply vessel with DPFire‑fighting or rescue craft
Decision Guide: Choose if the vessel requires precise thrust control, frequent low‑speed manoeuvring, or dynamic positioning – typical for tugs, ferries and offshore workboats. Avoid if the primary mission is high‑speed transit or if budget constraints limit acceptance of higher capital and maintenance costs.
Use Cases: The VSP 16R/20 is commonly installed on harbour tugs for rapid bollard‑pull manoeuvres, short‑run passenger ferries that need quick docking without tug assistance, and offshore supply vessels that must hold position under varying sea conditions using DP. It also sees use in fire‑fighting boats where rapid thrust reversal is critical.
VSP 18R/10
unverified
· 1800.0 kW
· Voith Schneider Propeller (VSP)
Power (kW)
1800
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Instantaneous thrust vectoring for superior manoeuvrability and station‑keeping
- Compact installation with low draft, suitable for shallow waters
- Effective for dynamic positioning and precise docking operations
- Robust stainless‑steel construction offering good corrosion resistance
Weaknesses
- Higher initial cost and more complex maintenance compared with conventional screw propellers
- Lower propulsive efficiency at high cruising speeds, limiting top speed potential
- Specialised spare parts and trained personnel required for service
- Noise and vibration levels can be higher in certain operating regimes
Typical Vessels:
Harbour tugCoastal ferryOffshore supply vesselDynamic positioning workboatIce‑class support vessel
Certifications:
DNV
Decision Guide: Choose if the vessel needs high manoeuvrability, rapid thrust reversal or dynamic positioning in confined or shallow waters. Avoid if the primary mission is long‑range, high‑speed transit where conventional propellers deliver better fuel efficiency and lower cost.
Use Cases: The VSP 18R/10 is commonly installed on harbour tugs for precise ship assist, coastal ferries for quick docking without bow thrusters, offshore supply vessels that require station‑keeping alongside rigs, and DP‑equipped workboats operating in congested ports or shallow bays.
VSP 18R/15
unverified
· 2700.0 kW
· Voith Schneider propeller
Power (kW)
2700
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Instantaneous thrust vectoring enables precise station keeping and tight turning circles.
- Compact installation with no rudders or additional steering gear reduces mechanical complexity.
- High thrust at low rpm (≈200 rpm) matches well with diesel‑electric drives common on DP vessels.
- Stainless‑steel blades give good corrosion resistance for marine environments.
Weaknesses
- Limited top speed compared with conventional screw propellers of similar power.
- Higher initial cost and specialized maintenance requirements.
- Noise and vibration levels can be higher at certain blade pitch settings.
- Efficiency drops off at high advance ratios, making it less suitable for long‑haul cruising.
Typical Vessels:
Harbour tugOffshore supply vesselDynamic positioning vesselFast ferryFire‑fighting craft
Decision Guide: Choose if: you need superior low‑speed maneuverability, precise thrust control for DP or harbor operations, and have space for a compact cycloidal unit. Avoid if: the vessel’s primary mission is high‑speed transit where propulsive efficiency at higher rpm is critical.
Use Cases: The VSP 18R/15 is commonly installed on harbour tugs that require rapid directional changes, offshore supply vessels that must hold position beside rigs, and fast ferries operating in confined waterways where tight turning radii are essential.
VSP 18R/20
unverified
· 3600.0 kW
· Voith Schneider Propeller
Power (kW)
3600
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Instantaneous vectorable thrust gives exceptional manoeuvrability and station‑keeping
- Low draft design suitable for shallow‑water operations
- Robust stainless‑steel blades handle high power (3.6 MW) with good corrosion resistance
- Ideal for dynamic positioning systems on offshore vessels
- Provides equal thrust in forward, reverse and lateral directions without gear changes
Weaknesses
- Propulsive efficiency is lower than conventional screw propellers at higher cruise speeds
- Higher initial capital cost and more complex control/gear arrangement
- Maintenance requires specialised knowledge and spare‑parts inventory
- Noise and vibration can be greater than a standard propeller, requiring mitigation measures
- Limited top speed capability due to low rpm design
Typical Vessels:
Harbour tugFire‑fighting boatOffshore supply vessel (DP)Passenger ferry in confined waterwaysDredger
Decision Guide: Choose if the vessel needs superior manoeuvrability, low draft operation or reliable dynamic positioning – e.g., tugs, DP‑equipped OSVs, ferries in tight ports. Avoid if primary mission is high‑speed transit where fuel efficiency outweighs thrust vectoring benefits.
Use Cases: The VSP 18R/20 is commonly installed on harbour tugs for rapid turning and reverse thrust, fire‑fighting craft that must hold position while pumping water, offshore supply vessels that require precise station‑keeping near rigs, and short‑route ferries navigating narrow channels where quick directional changes are essential.
VSP 20R/10
unverified
· 2000.0 kW
· Cycloidal propeller
Power (kW)
2000
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Instantaneous thrust vectoring enables precise station‑keeping and tight turning circles.
- High thrust output at relatively low shaft speed (≈200 rpm) reduces cavitation risk.
- Compact installation footprint compared with conventional twin‑screw arrangements.
- Excellent lateral thrust capability eliminates the need for separate bow thrusters on many vessels.
- Well suited for dynamic positioning and frequent start‑stop operations.
Weaknesses
- More complex mechanical arrangement leads to higher maintenance requirements than a standard screw propeller.
- Sensitivity to debris or foreign objects in the water can cause blade wear.
- Initial acquisition cost is typically higher than conventional propulsion units of similar power.
- Maximum achievable vessel speed is lower than that of high‑rpm axial screws for the same power rating.
- Noise and vibration levels can be higher, requiring additional acoustic mitigation on passenger vessels.
Typical Vessels:
Harbour tugCoast guard patrol boatShort‑route ferryOffshore supply vesselDynamic positioning workboat
Decision Guide: Choose if: the vessel requires superior low‑speed maneuverability, frequent directional changes, or dynamic positioning capability; space for conventional thrusters is limited. Avoid if: high cruising speed and fuel efficiency at full power are primary goals, or budget constraints preclude the higher upfront cost.
Use Cases: The VSP 20R/10 is commonly installed on harbor tugs that must push and pull ships in confined ports, fire‑fighting boats needing rapid side thrust, short‑haul ferries operating on tight schedules, and offshore support vessels that require precise station‑keeping while servicing wind turbines or platforms.
VSP 20R/15
unverified
· 3000.0 kW
· cycloidal propulsion
Power (kW)
3000
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Instantaneous 360° thrust direction change – ideal for tight harbour manoeuvres and DP operations.
- Low rotational speed (≈200 rpm) reduces cavitation risk and prolongs blade life.
- Compact installation footprint compared with conventional shaft‑line + rudder arrangements.
- High thrust at low ship speeds improves bollard pull for tugs and workboats.
Weaknesses
- Higher initial capital cost than a standard fixed‑pitch propeller system.
- Complex mechanical arrangement leads to increased maintenance skill requirements.
- Slightly lower propulsive efficiency in straight‑line cruise compared with conventional screws.
- Limited availability of spare parts in remote regions; long lead times for specialised blades.
Typical Vessels:
Harbour tugCoast‑guard cutterFerry (short‑route)Offshore supply vesselDynamic positioning workboat
Decision Guide: Choose if: you need exceptional manoeuvrability, rapid thrust reversal, or DP capability in confined waters; you can accommodate higher upfront cost and specialized maintenance. Avoid if: the vessel operates primarily on long straight routes where fuel efficiency is paramount, or budget constraints preclude the added complexity.
Use Cases: The VSP 20R/15 is commonly installed on harbour tugs for rapid bollard‑pull manoeuvres, short‑haul ferries that dock without tug assistance, and offshore supply vessels that require precise station‑keeping during cargo transfers. Its low‑speed high‑thrust characteristics also suit coast‑guard cutters performing search‑and‑rescue operations in tight coastal zones.
VSP 20R/20
unverified
· 4000.0 kW
· cycloidal propeller
Power (kW)
4000
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Instantaneous thrust vectoring enables zero‑radius turning and excellent station‑keeping.
- Compact installation with a low draft, suitable for shallow‑water workboats.
- High thrust at low RPM reduces cavitation risk and improves durability of the stainless steel blades.
- Integrated control system allows fine speed and direction adjustments for dynamic positioning.
Weaknesses
- Higher initial purchase price compared with conventional screw propellers.
- Complex mechanical arrangement leads to increased maintenance skill requirements.
- Slightly lower propulsive efficiency at steady cruise speeds versus a fixed‑pitch propeller.
- Limited availability of spare parts in remote regions; long lead times for major overhauls.
Typical Vessels:
Harbour tugCoast guard cutterOffshore supply vessel (DP)Passenger ferry with frequent dockingFire‑fighting workboat
Decision Guide: Choose if: the vessel needs exceptional manoeuvrability, low draft operation, or precise dynamic positioning (e.g., tugs, DP offshore vessels). Avoid if: project budget is tight, the primary mission is long‑distance cruising where propulsive efficiency dominates, or maintenance infrastructure for cycloidal units is lacking.
Use Cases: The VSP 20R/20 is commonly installed on harbour tugs that must push and pull large ships in confined ports, on offshore supply vessels that require DP capability to hold position beside rigs, and on high‑frequency passenger ferries where rapid direction changes between berths are essential. It also sees use on coast‑guard or fire‑fighting craft that need immediate thrust reversal without gear shifts.
VSP 22R/10
unverified
· 2200.0 kW
· cycloidal (Voith Schneider) propulsion
Power (kW)
2200
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Instantaneous change of thrust direction without need for rudders or gearboxes
- Very high bollard pull and low‑speed thrust efficiency, ideal for tugging and DP operations
- Compact installation footprint compared with conventional shaft line + thruster arrangements
- Low rotational speed reduces cavitation risk and improves propeller life
- Excellent station‑keeping capability for offshore support vessels
Weaknesses
- Propulsive efficiency drops at higher vessel speeds, making it less suitable for fast transit ships
- Higher capital cost and more complex control/gear system than a standard screw propeller
- Specialised maintenance and spare‑parts supply chain required
- Limited maximum speed envelope (typically <15 kn) due to design geometry
- Potential for higher acoustic signature at certain operating points
Typical Vessels:
Harbour tugOffshore supply vesselDP‑class workboatShort‑route ferryIce‑support or polar auxiliary vessel
Decision Guide: Choose the VSP 22R/10 when you need precise, rapid thrust vectoring and high bollard pull for tugging, DP station‑keeping, or short‑range ferries. Avoid it on vessels that require sustained high cruise speeds, long‑haul efficiency, or where upfront cost and maintenance complexity are critical constraints.
Use Cases: The VSP 22R/10 is commonly installed on harbor tugs performing ship assist, offshore supply ships that must hold position near rigs, dynamic positioning workboats, and short‑distance ferries operating in confined waterways where rapid manoeuvre response is essential. Its low‑speed thrust advantage also makes it suitable for ice‑class support vessels that need strong pull at reduced speeds.
VSP 22R/15
unverified
· 3300.0 kW
· Voith Schneider cycloidal propeller
Power (kW)
3300
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Instantaneous thrust vectoring gives superior manoeuvrability for tight harbor work and DP operations.
- Low rotational speed (≈200 rpm) reduces cavitation risk and allows use of stainless‑steel blades for corrosion resistance.
- Compact installation footprint and low draft are ideal for vessels operating in shallow waters.
- Integrated control system enables precise thrust magnitude and direction, improving fuel efficiency during low‑speed manoeuvres.
Weaknesses
- Higher initial capital cost compared with conventional screw propellers.
- Complex mechanical arrangement leads to increased maintenance intervals and requires specialised spare parts.
- Overall propulsive efficiency drops at higher ship speeds; not suited for fast cargo carriers.
- Operational expertise is needed to optimise control settings, increasing crew training requirements.
Typical Vessels:
Harbour tugOffshore supply vessel (DP)Fire‑fighting boatFerry / passenger tenderDredger
Certifications:
DNV
Decision Guide: Choose if the vessel needs high manoeuvrability, low draft and precise station‑keeping (e.g., tugs, DP‑enabled OSVs, fire‑boats). Avoid if the primary requirement is high cruising speed or cost‑sensitive propulsion where a conventional screw offers better efficiency.
Use Cases: The VSP 22R/15 is commonly installed on harbour tugs for rapid turning and thrust reversal, on offshore supply vessels that require dynamic positioning in rough seas, and on fire‑fighting craft that must hold position while operating water cannons. Its compact size also makes it suitable for shallow‑water ferries and dredgers where space and draft are limited.
VSP 22R/20
unverified
· 4400.0 kW
· cycloidal propulsion
Power (kW)
4400
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Instantaneous thrust vectoring enables zero‑radius turning and excellent station keeping.
- Compact installation – no need for separate rudders or steering gear.
- High manoeuvring efficiency at low to medium speeds, ideal for tugging and ferry operations.
- Robust stainless‑steel blades provide good resistance to corrosion in harsh marine environments.
Weaknesses
- Lower propulsive efficiency than conventional screw propellers at high cruise speeds.
- Higher initial capital cost and specialized maintenance requirements.
- Limited suitability for very large, high‑speed vessels due to power density constraints.
- Noise and vibration levels can be higher without proper acoustic treatment.
Typical Vessels:
Harbour tugCoast guard cutterFerry (short‑route)Offshore supply vesselDynamic positioning workboat
Decision Guide: Choose if: the vessel needs superior low‑speed manoeuvrability, frequent direction changes, or precise station keeping (e.g., tugs, ferries, DP vessels). Avoid if: the primary mission is high‑speed transit where conventional propellers deliver better fuel efficiency and lower lifecycle cost.
Use Cases: The VSP 22R/20 is commonly installed on harbor tugs for rapid response, short‑haul passenger ferries operating in confined waterways, offshore supply ships that require dynamic positioning, and patrol vessels that need tight turning circles. Its ability to generate thrust in any direction without a separate steering gear makes it valuable wherever space is limited and manoeuvrability is paramount.
VSP 24R/10
unverified
· 2400.0 kW
· Voith Schneider propeller
Power (kW)
2400
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Instantaneous thrust vectoring enables superior low‑speed manoeuvring and dynamic positioning.
- Compact installation footprint compared with conventional shaft line + rudder arrangements.
- Low cavitation and noise levels, beneficial for crew comfort and marine life.
- High reliability in harsh environments; stainless steel blades resist corrosion.
- Well suited to vessels that require frequent direction changes such as tugs and ferries.
Weaknesses
- Higher capital cost and more complex gearbox/drive train than a standard propeller.
- Maintenance intensive due to multiple rotating blades and precision gear sets.
- Limited top‑speed efficiency; best performance is at moderate speeds (≈200 rpm).
- Requires specialised crew training for optimal operation and troubleshooting.
- Spare parts inventory can be larger because of the unique design.
Typical Vessels:
Harbour tugPassenger ferryOffshore supply vesselDredgerDynamic positioning workboat
Decision Guide: Choose if: you need exceptional manoeuvrability, frequent low‑speed direction changes, or DP capability in confined waters. Avoid if: the primary mission is high cruising speed over long distances or budget constraints dominate equipment selection.
Use Cases: The VSP 24R/10 is commonly installed on harbour tugs for ship assist, fast ferries operating in tight ports, offshore supply vessels that must hold position beside rigs, and dredging craft requiring precise thrust control during excavation.
VSP 24R/15
unverified
· 3600.0 kW
· Voith Schneider Propeller
Power (kW)
3600
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Instantaneous thrust vectoring enables exceptional station‑keeping and tight turning circles.
- Compact installation footprint suitable for vessels with limited aft space or low draft.
- Low vibration and noise levels compared with conventional propellers of similar power.
- Stainless‑steel blades offer good corrosion resistance in marine environments.
Weaknesses
- Propulsive efficiency drops at higher vessel speeds, making it less suited for long‑haul cruising.
- Higher initial cost and more complex gear/drive arrangement than a standard shaft line.
- Maintenance requires specialised knowledge of the vertical blade mechanism.
- Limited thrust output relative to size; not ideal for very large bulk carriers or tankers.
Typical Vessels:
Harbour tugCoast‑guard patrol boatFerry (short‑route)Offshore supply vesselDynamic positioning workboat
Decision Guide: Choose if the vessel needs high manoeuvrability, frequent direction changes, or low‑draft operation such as tugs, ferries and DP workboats. Avoid if the primary mission is sustained high‑speed transit or heavy cargo transport where conventional screw propellers are more efficient.
Use Cases: The VSP 24R/15 is commonly installed on harbor tugs for rapid bollard‑pull maneuvers, short‑range ferries operating in confined ports, and offshore supply vessels that require precise station‑keeping while loading or supporting offshore platforms.
VSP 24R/20
unverified
· 4800.0 kW
· Voith Schneider cycloidal propeller
Power (kW)
4800
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Instantaneous thrust vectoring gives superior manoeuvrability for tight harbor operations or DP work.
- Compact installation – the unit fits within a relatively small hull space compared to conventional shafts and rudders.
- Low vibration and noise levels due to constant‑speed rotation of the blades.
- High thrust at low forward speeds, ideal for tugs, ferries and offshore support vessels.
- Stainless‑steel construction offers good corrosion resistance in marine environments.
Weaknesses
- Mechanical complexity leads to higher maintenance requirements and specialised spare parts.
- Overall propulsive efficiency is lower than a well‑designed conventional screw at high cruise speeds.
- Initial capital cost is significantly higher than standard shaft line solutions.
- Limited maximum diameter restricts use on very large, high‑speed vessels.
- Requires skilled operators or integrated control systems to exploit full performance.
Typical Vessels:
Harbour tugOffshore supply vesselFire‑fighting boatDP‑class workboatRoll‑on/roll‑off ferry
Decision Guide: Choose if the vessel needs exceptional low‑speed manoeuvrability, dynamic positioning or operation in confined waters. Avoid if primary mission is long‑range high‑speed transit where fuel efficiency and lower acquisition cost are paramount.
Use Cases: The VSP 24R/20 is commonly installed on harbour tugs for rapid bollard‑pull maneuvers, offshore supply vessels that require precise station‑keeping alongside rigs, fire‑fighting craft that need instant thrust reversal, and DP‑enabled workboats operating in congested ports or shallow drafts.
VSP 26R/10
unverified
· 2600.0 kW
· Voith Schneider propulsion
Power (kW)
2600
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Instantaneous thrust vectoring enables superior manoeuvrability and station‑keeping.
- Compact installation with no separate rudder or steering gear reduces hull space requirements.
- Effective low‑speed thrust generation, ideal for tugging, ferry berthing and DP operations.
- Stainless‑steel blades offer good corrosion resistance in harsh marine environments.
Weaknesses
- Complex mechanical arrangement leads to higher maintenance effort compared with conventional shafts.
- Initial acquisition cost is significantly greater than standard propeller‑rudder sets.
- Efficiency drops at higher vessel speeds; not optimal for long‑haul, high‑speed vessels.
- Noise and vibration levels can be higher, requiring additional mitigation measures.
Typical Vessels:
Harbor tugFire‑fighting / rescue boatOffshore supply vesselPassenger ferry with frequent stopsDynamic positioning support vessel
Decision Guide: Choose if the vessel needs high manoeuvrability, precise station‑keeping or DP capability in confined waters. Avoid if the primary mission is sustained high‑speed cruising or budget constraints dominate the propulsion selection.
Use Cases: The VSP 26R/10 is commonly installed on harbor tugs for rapid berthing assistance, offshore supply ships that must hold position alongside rigs, and short‑run ferries where frequent direction changes are required. It also serves fire‑fighting craft where quick thrust reversal is critical.
VSP 26R/15
unverified
· 3900.0 kW
· Voith Schneider cycloidal propeller
Power (kW)
3900
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Instantaneous thrust vectoring for superior manoeuvrability and station‑keeping
- Compact installation footprint compared with conventional shaft lines
- Low vibration and noise levels, beneficial for crew comfort and acoustic-sensitive operations
- Effective low‑speed efficiency, ideal for tugging, DP and ferry services
Weaknesses
- Higher initial purchase price than standard screw propellers
- Complex gear and blade mechanisms increase maintenance workload and spare‑part inventory
- Peak efficiency drops at higher vessel speeds; not optimal for long‑haul cruising
- Sensitive to fouling on the vertical blades, requiring regular cleaning in dirty waters
Typical Vessels:
Harbour tugOffshore supply vessel (DP)Fire‑fighting boatPassenger ferryIce‑class workboat
Certifications:
DNVABS
Decision Guide: Choose if the vessel needs exceptional low‑speed manoeuvrability, dynamic positioning or frequent direction changes in confined waters. Avoid if the primary mission is high‑speed transit over long distances or when budget constraints limit upfront capital and maintenance costs.
Use Cases: The VSP 26R/15 is commonly installed on harbour tugs for rapid bollard‑pull manoeuvres, offshore supply vessels that require precise station‑keeping during cargo transfer, fire‑boats that must hold position while operating water cannons, and short‑route passenger ferries navigating tight ports.
VSP 26R/20
unverified
· 5200.0 kW
· cycloidal propulsion
Power (kW)
5200
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Instantaneous 360° thrust direction gives exceptional manoeuvrability and station‑keeping.
- High thrust per unit diameter – suitable for high‑power tugs and DP vessels.
- Low cavitation risk at low speeds, improving blade life in shallow or debris‑laden waters.
- Compact installation compared with conventional shaft line + rudder arrangements.
Weaknesses
- Complex mechanical arrangement leads to higher maintenance intervals and specialised spare parts.
- Slightly lower propulsive efficiency than a well‑optimised fixed‑pitch screw at cruising speeds above ~12 kn.
- Higher initial capital cost versus conventional propeller‑rudder sets.
- Noise and vibration levels can be higher, requiring additional acoustic mitigation on passenger vessels.
Typical Vessels:
Harbour tugOffshore supply vessel (DP)Roll‑on/roll‑off ferryCoastal patrol boatIce‑class workboat
Certifications:
DNVABS
Decision Guide: Choose if the vessel needs precise low‑speed thrust control, frequent direction changes or dynamic positioning – e.g., tugs, DP offshore vessels, ferries in confined waterways. Avoid if the primary mission is sustained high‑speed transit where propulsive efficiency outweighs manoeuvrability.
Use Cases: The VSP 26R/20 is commonly installed on harbour tugs for ship assist, on offshore supply ships that must hold position beside rigs, and on short‑route ferries navigating tight ports where rapid thrust reversal cuts turnaround time.
VSP 28R/10
unverified
· 2800.0 kW
· Voith Schneider Propeller (VSP)
Power (kW)
2800
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Instantaneous change of thrust direction without need for rudders or gearboxes
- High manoeuvrability and station‑keeping capability, excellent for DP operations
- Compact installation footprint compared to conventional shaft line + thruster arrangements
- Low vibration and noise levels at low to medium speeds
- Good thrust per kilowatt ratio for vessels operating primarily in the 0–12 kn range
Weaknesses
- Lower propulsive efficiency at higher vessel speeds versus a conventional screw propeller
- Higher initial capital cost and more complex control system
- Maintenance intensive due to multiple rotating blades and gear mechanisms
- Limited top‑speed capability; not suited for high‑speed cargo ships
- Sensitivity to debris or ice ingestion in harsh environments
Typical Vessels:
Harbour tugsPilot boatsFerries (short‑route, roll‑on/roll‑off)Offshore supply vessels with DPWorkboats and fire‑fighting craft
Certifications:
DNV
Decision Guide: Choose the VSP 28R/10 when precise low‑speed manoeuvring, rapid thrust reversal, or dynamic positioning are critical – e.g., tugs, ferries, and offshore DP vessels. Avoid it on high‑speed cargo carriers where propulsive efficiency at cruise speed outweighs maneuverability benefits.
Use Cases: The VSP 28R/10 is typically installed on vessels that operate in confined waters or require frequent thrust direction changes, such as harbour tugs docking large ships, ferries shuttling between terminals, and offshore supply craft maintaining position beside rigs.
VSP 28R/15
unverified
· 4200.0 kW
· Cycloidal propulsion
Power (kW)
4200
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Exceptional manoeuvrability with instantaneous thrust direction change
- High thrust efficiency at low to medium speeds, ideal for tugging and DP operations
- Compact installation footprint compared with conventional shaft lines
- Robust stainless‑steel construction suitable for harsh marine environments
- Integrated steering eliminates the need for separate rudders or thrusters
Weaknesses
- Higher initial purchase price than a standard screw propeller
- Increased mechanical complexity leading to more intensive maintenance
- Reduced efficiency at high cruising speeds, limiting use on fast vessels
- Potentially higher acoustic signature and vibration levels
- Limited maximum diameter restricts applicability on very large ships
Typical Vessels:
Harbour tugOffshore supply vesselDynamic positioning vesselFerry (short‑route)Fire‑fighting boat
Decision Guide: Choose if the vessel requires superior low‑speed manoeuvrability, dynamic positioning or operation in confined waterways. Avoid if the primary mission is high‑speed transit, cost sensitivity is paramount, or a larger propeller diameter is needed for maximum thrust.
Use Cases: Commonly installed on harbor tugs for rapid turning and bollard pull, offshore supply vessels that need precise station‑keeping during crane operations, DP‑class workboats, and short‑route ferries navigating tight ports.
VSP 28R/20
unverified
· 5600.0 kW
· Voith Schneider propulsion
Power (kW)
5600
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Exceptional maneuverability and 360° thrust direction control, ideal for tugs and DP vessels
- Instantaneous thrust reversal without gear changes, reducing response time in tight operations
- Compact installation footprint and low draft compared to conventional shaft lines
- Robust stainless‑steel blade construction suitable for harsh marine environments
- Proven reliability in high‑power applications up to 5.6 MW
Weaknesses
- Lower propulsive efficiency at constant cruise speeds versus conventional screw propellers
- Higher initial capital cost and more complex maintenance due to rotating hub and blade gear train
- Increased acoustic signature, which may be a concern for noise‑sensitive operations
- Limited availability of spare parts in remote regions compared with standard shafts
- Design optimisation required for each hull form; not a drop‑in replacement
Typical Vessels:
Harbour tugOffshore supply vesselFire‑fighting boatDynamic positioning platformCrew transfer ferry
Decision Guide: Choose if the vessel requires superior low‑speed maneuverability, rapid thrust reversal, or dynamic positioning in confined waters. Avoid if primary mission is long‑distance fuel‑efficient cruising where conventional screw propellers deliver better economy.
Use Cases: The VSP 28R/20 is commonly installed on harbor tugs that must push and pull large ships within ports, offshore supply vessels needing precise station‑keeping near rigs, fire‑fighting craft that require instant directional changes, and DP‑enabled crew transfer ferries operating in congested or shallow waterways.
VSP 30R/10
unverified
· 3000.0 kW
· Voith Schneider cycloidal propeller
Power (kW)
3000
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Instantaneous thrust vectoring enables precise station‑keeping and tight turning circles.
- Compact installation – the unit combines propulsion and steering in a single housing.
- Effective low‑speed thrust generation, ideal for tugging and DP operations.
- Low cavitation risk at the specified 200 rpm operating speed.
Weaknesses
- Lower propulsive efficiency compared with conventional screw propellers at higher ship speeds.
- Higher initial capital cost and more complex maintenance due to multiple rotating blades.
- Limited suitability for vessels that require high cruising speeds (>15 kn).
- Noise and vibration can be higher than a standard fixed‑pitch propeller.
Typical Vessels:
Harbour tugOffshore supply vesselDynamic positioning vesselRoll‑on/roll‑off ferry (short routes)Fire‑fighting boat
Decision Guide: Choose if: the vessel needs precise thrust control, frequent low‑speed maneuvers, or dynamic positioning capability. Avoid if: high cruising speed efficiency is a priority or budget constraints limit upfront cost.
Use Cases: Commonly installed as main propulsion on harbor tugs and as auxiliary thrusters on offshore supply ships that require rapid heading changes and station keeping in confined waters or during DP operations.
VSP 30R/15
unverified
· 4500.0 kW
· Cycloidal propulsion
Power (kW)
4500
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Instantaneous thrust vectoring enables precise station‑keeping and tight turning circles.
- Low draft design suitable for shallow‑water operations.
- High manoeuvrability reduces reliance on bow thrusters or tug assistance.
- Robust stainless‑steel blades offer good corrosion resistance in marine environments.
Weaknesses
- Mechanically complex system leads to higher maintenance requirements and costs.
- Lower propulsive efficiency at high cruising speeds compared with conventional screw propellers.
- Limited top speed makes it unsuitable for vessels that require sustained high‑speed transit.
- Initial capital cost is higher than standard shaft line solutions.
Typical Vessels:
Harbour tugFire‑fighting boatOffshore supply vessel (DP)Passenger ferryDynamic positioning workboat
Decision Guide: Choose if: you need superior manoeuvrability, low draft and frequent direction changes (e.g., tugs, ferries, DP vessels). Avoid if: the vessel operates primarily at high cruising speeds where propulsive efficiency is critical or budget constraints limit upfront investment.
Use Cases: The VSP 30R/15 is commonly installed on harbour tugs for rapid response, fire‑fighting craft that must hold position precisely, offshore supply ships with dynamic positioning, and short‑route ferries navigating tight ports.
VSP 30R/20
unverified
· 6000.0 kW
· cycloidal propeller
Power (kW)
6000
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Instantaneous thrust vectoring enables zero‑radius turning and superior station‑keeping.
- Compact installation – no rudders or stern thrusters required, saving hull space.
- High thrust at low speeds ideal for tugging, ferry docking and DP operations.
- Robust stainless‑steel blade construction suitable for harsh marine environments.
Weaknesses
- Lower propulsive efficiency at higher ship speeds compared with conventional screw propellers.
- Higher initial capital cost and specialised maintenance expertise required.
- Limited suitability for vessels that need sustained high‑speed cruising (e.g., container ships).
- Noise and vibration levels can be higher than a standard propeller, requiring additional mitigation.
Typical Vessels:
Harbour tugRoll‑on/roll‑off ferryOffshore supply vesselDynamic positioning workboat
Decision Guide: Choose if: the vessel needs exceptional manoeuvrability, frequent low‑speed operations, or precise DP station‑keeping; space for conventional thrusters is limited. Avoid if: the primary mission is high‑speed transit where propulsive efficiency and fuel economy dominate.
Use Cases: The VSP 30R/20 is commonly installed on harbor tugs for rapid bollard‑pull manoeuvres, on short‑route ferries that must dock quickly and repeatedly, and on offshore supply vessels that require fine positional control while working near platforms or wind farms.
VSP 32R/10
unverified
· 3200.0 kW
· Voith Schneider propeller
Power (kW)
3200
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- High thrust at very low shaft speeds (200 rpm) suitable for tug and DP operations
- Instantaneous change of thrust direction without need for rudders or gearboxes
- Compact installation footprint compared with conventional screw + thruster arrangements
- Stainless‑steel blades give good corrosion resistance in marine environments
- Well suited to vessels requiring precise station‑keeping (DP2, offshore supply)
Weaknesses
- Lower propulsive efficiency at higher cruising speeds than a conventional fixed‑pitch screw
- Higher initial capital cost and more complex gearbox arrangement
- Maintenance is more specialised due to the rotating blade hub and gear train
- Noise and vibration levels can be higher, requiring additional mitigation on passenger vessels
- Limited maximum speed envelope (typically up to 12–14 knots)
Typical Vessels:
Harbour tugOffshore supply vesselDP‑equipped platform support shipFire‑fighting boatShort‑route passenger ferry
Certifications:
IMO Type Approval (MSC.1/Circ.1400)DNV Class
Decision Guide: Choose if: the vessel needs excellent low‑speed thrust control, frequent maneuvering in confined waters, or dynamic positioning capability. Avoid if: the primary mission is high‑speed transit where propulsive efficiency outweighs maneuverability benefits.
Use Cases: The VSP 32R/10 is commonly installed on harbor tugs and offshore supply vessels that operate with DP systems, providing rapid thrust vectoring for station‑keeping during offshore loading operations or in tight port approaches. It is also used on fire‑fighting craft where quick directional changes are critical.
VSP 32R/15
unverified
· 4800.0 kW
· cycloidal propulsion
Power (kW)
4800
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Instantaneous thrust vectoring enables superior maneuverability and station‑keeping.
- Effective low‑speed thrust generation, ideal for tugging and DP operations.
- Compact installation with a relatively small draft compared to conventional propellers.
- Stainless‑steel construction offers good corrosion resistance in marine environments.
Weaknesses
- Complex gear and blade mechanisms lead to higher maintenance demands.
- Lower propulsive efficiency at high ship speeds versus standard screw propellers.
- Higher upfront capital cost and specialised spare parts inventory.
- Potential for increased noise and vibration if not properly tuned.
Typical Vessels:
Harbour tugPilot boatShort‑run ferryOffshore supply vessel (DP class)Dredger
Decision Guide: Choose if the vessel needs exceptional manoeuvrability, low‑draft operation, or dynamic positioning capability. Avoid if the primary mission is high‑speed transit where conventional propellers deliver better fuel efficiency and lower lifecycle cost.
Use Cases: The VSP 32R/15 is commonly installed on harbour tugs for ship assist, pilot boats navigating confined waterways, short‑distance ferries that require rapid direction changes, and offshore supply vessels that must maintain precise position alongside platforms.
VSP 32R/20
unverified
· 6400.0 kW
· Voith Schneider Propeller
Power (kW)
6400
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Exceptional maneuverability and 360° thrust direction control
- High thrust efficiency at low speeds, ideal for tugging and DP operations
- Compact installation footprint compared with conventional shaft lines
- Rapid response to helm inputs – no need for gear changes or rudders
- Stainless‑steel blades offer good corrosion resistance in marine environments
Weaknesses
- Complex mechanical arrangement leads to higher maintenance requirements
- Higher initial capital cost than standard propeller‑rudder sets
- Limited maximum vessel speed; not suited for high‑speed transit vessels
- Sensitivity to debris or ice ingestion due to exposed rotating blades
- Specialised spare parts and trained personnel are required
Typical Vessels:
Harbour tugFire‑fighting / rescue boatOffshore supply vessel with DPRoll‑on/roll‑off ferry operating in confined portsDynamic positioning platform support ship
Decision Guide: Choose if the vessel needs precise low‑speed thrust control, frequent manoeuvring in tight spaces, or dynamic positioning capability. Avoid if the primary mission is high‑speed cruising, cost sensitivity outweighs maneuverability benefits, or operating environments involve heavy debris/ice that could damage exposed blades.
Use Cases: The VSP 32R/20 is typically installed on harbour tugs and fire‑boats for rapid directional changes, on offshore supply vessels where DP is required to hold position during cargo operations, and on short‑haul ferries navigating narrow channels where tight turning circles are essential.
VSP 36R/10
unverified
· 3600.0 kW
· Voith Schneider cycloidal propeller
Power (kW)
3600
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Instantaneous and 360° thrust direction control for exceptional manoeuvrability
- Rapid thrust reversal without changing shaft rotation, ideal for tug and DP operations
- Compact installation with low draft, suitable for vessels operating in confined waters
- Robust stainless‑steel blade construction offers good corrosion resistance
- Effective low‑speed thrust generation, enhancing bollard pull capability
Weaknesses
- Lower propulsive efficiency at higher cruising speeds compared with conventional screws
- Higher initial capital cost and more complex maintenance procedures
- Increased acoustic signature and vibration relative to standard propellers
- Limited maximum vessel speed due to design focus on thrust control rather than high‑speed efficiency
- Specialised spare parts and support may be required
Typical Vessels:
Harbor TugFire‑fighting VesselOffshore Supply VesselDP‑class WorkboatFerry
Decision Guide: Choose if: you need precise, rapid thrust vectoring for harbour manoeuvring, DP station‑keeping, or short‑run high‑bollard‑pull tasks; vessel operates at low to moderate speeds and benefits from a compact, low‑draft propulsion layout. Avoid if: the primary mission is sustained high‑speed transit where conventional screw efficiency outweighs manoeuvre advantages, or budget constraints preclude higher upfront costs.
Use Cases: The VSP 36R/10 is commonly installed on harbour tugs for ship assist and escort duties, fire‑fighting boats that require quick directional changes, offshore supply vessels that need DP capability while station‑keeping near platforms, and short‑route ferries docking in tight terminals. Its ability to reverse thrust instantly makes it valuable for emergency response and precise positioning tasks.
VSP 36R/15
unverified
· 5400.0 kW
· Voith Schneider Propeller
Power (kW)
5400
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Instantaneous thrust direction change enables exceptional maneuverability, ideal for tugging and DP operations.
- Compact installation with low draft suits shallow‑water vessels.
- High thrust at low rotational speeds improves fuel efficiency in slow‑speed service.
- Robust stainless‑steel blades offer good corrosion resistance in marine environments.
Weaknesses
- Mechanically complex; requires specialized maintenance and skilled personnel.
- Higher initial capital cost compared with conventional screw propellers.
- Efficiency drops at higher vessel speeds, limiting use on fast ferries or bulk carriers.
- Potential for increased noise and vibration if not properly balanced.
Typical Vessels:
Harbor tugOffshore supply vesselDP‑class workboatFire‑fighting craftShort‑run ferry
Decision Guide: Choose if the vessel needs superior low‑speed maneuverability, dynamic positioning or operation in confined/shallow waters. Avoid if the primary mission is high‑speed transit or if budget constraints limit upfront investment.
Use Cases: Commonly installed on harbor tugs for ship assist, offshore supply vessels that require precise station‑keeping, fire‑fighting boats needing rapid thrust reversal, and short‑run ferries with frequent docking cycles.
VSP 36R/20
unverified
· 7200.0 kW
· cycloidal propeller
Power (kW)
7200
Speed (rpm)
200
Blade count
5
Material
Stainless
Strengths
- Full 360° thrust vectoring gives unparalleled manoeuvrability and station‑keeping capability.
- Low draft installation suitable for shallow‑water operations.
- Rapid response to control inputs, ideal for dynamic positioning (DP) systems.
- Compact layout integrates propulsion and steering in a single unit, freeing hull space.
- Proven reliability on tugs and ferries with long service histories.
Weaknesses
- Higher initial capital cost compared with conventional screw propellers.
- More complex gear and blade mechanisms increase maintenance requirements.
- Peak efficiency is lower at high cruising speeds; best suited for low‑to‑moderate speed vessels.
- Limited availability of spare parts in remote regions may affect downtime.
- Noise and vibration levels can be higher, requiring additional acoustic mitigation.
Typical Vessels:
Harbour tugCoastal ferry / Ro‑Ro passenger vesselOffshore supply vessel (OSV)Dynamic positioning research or survey shipDredger
Certifications:
DNV
Decision Guide: Choose if: the vessel operates in confined waterways, requires frequent thrust reversal, needs precise station‑keeping or DP, and benefits from a shallow draft. Avoid if: the primary mission is high‑speed transit over long distances where propulsive efficiency dominates, or when budget constraints limit upfront capital expenditure.
Use Cases: The VSP 36R/20 is commonly installed on harbor tugs that must push and pull large ships in tight ports, on short‑haul passenger ferries navigating narrow channels, and on offshore supply craft that hold position beside rigs using DP. It also appears on dredgers where rapid thrust changes aid sediment handling.