Optimization of Waterjet Propulsion for High-Speed Ships

Gas turbine-waterjet propulsion offers significant advantages in many high-speed or special purpose ships, which generally have speed capability above 30 knots and installed power-toweight ratios above 10 hp per full-load ton. Included are destroyers of the destroyer (DD) type and some smaller destroyer leaders (DL), hydrofoils above 40 knots, surface effect ships, and planing craft. Optimization of gas turbine-water jet installations for maximum net thrust (system thrust less drag associated with propulsion system) depends primarily on the L/D ratio of the basic hull, design speed, ship length, and component efficiencies. The major components are the inlet, pump, gearbox, gas turbine, and associated required auxiliaries. For high-speed ships, propulsive coefficients of 60-65% are possible with conservative component-loss assumptions.