Pump-jet
From Biocrawler, the free encyclopedia.
Typical 'jet ski' pump jet
A pump-jet is a marine propulsion system that creates a jet of water for impulse. The mechanical arrangement may be a ducted propeller with nozzle, or a centrifugal pump and nozzle.
Pump jets have some advantages over bare propellers for certain applications; higher power density (with respect to volume) and ultra-quiet designs for submarines, the Trafalgar class is an example. They protect the rotating element in shallow water and are safer around swimmers.
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