The largest waterjet so far in the Rolls-Royce Kamewa FF series has now been introduced. It extends the power range of these axial flow aluminium waterjets to 1,800 kW.
“As a rough guide, a boat with a twin FF600 installation would have an all-up weight including equipment and fuel of about 60 tons for optimum performance,” said Tomas Renlund, director of the aluminium waterjet business. “But since we tailor the impeller to suit the application and can customise this type of jet to a considerable extent, each case should be considered individually.”
In common with the other units at the smaller end of the Rolls-Royce waterjet range, the FF600 is constructed in aluminium, with the impeller, its housing, shafts and the operating cylinders for steering and reversing made of stainless steel. The inlet duct is fabricated from aluminium sheet to an optimised hydrodynamic profile and the mounting flanges are supplied in two versions; one for welding direct into an aluminium hull, the other for bolting into hulls made of other materials.
Reverse and steering hydraulic cylinders are mounted inboard, and close attention has been paid to reducing risk to the environment.The actuating cylinders are anchored to a flange part way along the inlet duct next to the thrust bearing. This flange is designed so that it can be welded to, allowing the jet unit to be incorporated as part of an aft collision bulkhead structure.
The FF600 can be supplied either as a steerable and reversible unit or as a pure booster without the steering and reversing components. A Rolls-Royce interceptor system can be integrated with this waterjet, mounted below the impeller chamber
and linked to the Rolls-Royce electronic control system. Combining all these elements provides powerful thrust, joystick control of manoeuvring and independent control of vessel roll, trim and attitude in a turn.
With the introduction of the Kamewa FF600, this range of axial flow aluminium waterjets covers the power range from 260kW to 1,800kW per jet in 13 frame sizes, which covers the requirements of workboats, smaller military craft and many yachts. Rational production and standardisation enables them to be offered at a competitive price, while tailoring the impeller to suit the boat maximises performance and efficiency. The smaller units in the Kamewa FF range are more standardised, but with the larger waterjets such as the FF600 there is a greater degree of flexibility, allowing customers’ specific requirements to be met.
Further up the power scale, Rolls-Royce offers a complete range of waterjets covering input powers per unit up to 50,000kW.