Wärtsilä Waterjet Propulsion Systems

Wärtsilä waterjet propulsion systems provide propulsion for high-speed vessels, where waterjets outperform propellers at service speeds above 25–30 knots. Water enters through a hull inlet, is accelerated by an axial-flow pump impeller, and exits through a steering nozzle, with a reversing bucket redirecting flow for astern and manoeuvring.

Waterjet families

• Modular waterjets (WXJ series): up to ~33,000 kW; axial pump design with improved thrust and cavitation margins; highly customisable; duplex stainless steel construction
• Midsize waterjets: 1,000–4,500 kW in five standard sizes; pre-assembled skid with inlet duct for fast installation; steer/reverse (SR) or booster executions

Key features

• Axial-pump design, inboard-mounted thrust bearing block and inboard hydraulics
• No exposed appendages below the hull, enabling shallow-draft operation
• Manoeuvrability at all speeds, including crash stops and J-turns
• Low noise and vibration
• Integration with electric and hybrid propulsion, including battery-electric and LNG-fuelled ferries
• Wärtsilä ProTouch propulsion controls
• Waterjet Data Collection Unit (WDCU) monitoring RPM, steering angles, temperatures and pressures for predictive maintenance

Applications

Fast ferries, littoral combat ships, fast patrol boats, rescue vessels, fast yachts, fast supply vessels and workboats, and landing craft. References include the battery-electric ferry China Zorilla with eight Wärtsilä axial-flow waterjets.