Kongsberg Aluminium waterjets
Kongsberg aluminium waterjets provide shaft‑less thrust generation for high‑speed vessels, featuring a lightweight corrosion‑resistant aluminium pump housing.
Inspector Detail
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Common issues
- Impeller blade cavitation erosion, especially at higher speeds or with intake fouling
- Bearing wear in the shaft seal/bearing assembly of the jet unit
- Intake grid blockage or damage from debris
- Steering and reverse bucket actuator wear or hydraulic leakage
- Galvanic corrosion of the aluminium housing where anode protection has been neglected
- Shaft seal leakage allowing water ingress into the bearing housing
- Mounting flange or bolt looseness after vibration over time
Inspection checklist
- Inspect impeller blades for cavitation pitting or erosion
- Check the intake grid for blockage, damage, or missing bars
- Check steering and reverse bucket operation for smoothness and leaks
- Check the shaft seal for water ingress into the bearing housing
- Inspect sacrificial anodes on the jet unit and surrounding hull area
- Inspect the aluminium housing for corrosion, particularly at dissimilar-metal joints
- Check hydraulic system pressure and fluid condition for steering/reverse actuators
- Check mounting bolts and flange for tightness and corrosion
Service intervals
| Sacrificial anode inspection/renewal | typically every 6-12 months depending on water conditions - confirm against actual anode wastage observed |
| Impeller and wear ring inspection | at drydocking, or per Kongsberg's stated running-hour interval |
| Hydraulic fluid change for steering/reverse actuators | per the manufacturer's stated interval |
| Shaft seal inspection | at drydocking |
Typical wear limits
| Impeller tip clearance | wear beyond the manufacturer's stated clearance reduces thrust efficiency and should trigger renewal - confirm the exact figure against Kongsberg's own tolerance for this unit rather than a generic value |
Ranges are typical for this design class. Always confirm against the manufacturer documentation for your serial number.
Critical spares
- Impeller
- Wear rings/liners
- Shaft seal kit
- Sacrificial anodes
- Steering/reverse actuator seal kit
Safety
- High-velocity water discharge from the nozzle when running - keep clear of intake and discharge while operating
- Hydraulic system pressure in the steering/reverse actuation circuit
- Galvanic corrosion of the aluminium housing if anode protection is neglected, weakening structure over time
- Entrapment risk when clearing debris from the intake grid
Class survey
Class checks the waterjet as part of the propulsion system: anode condition, housing corrosion/integrity, and function testing of steering and reverse mechanisms, together with alignment and mounting security, typically confirmed at drydock survey.
Components & Design
Component data being added…
Technical Data
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