A pump-jet or water jet is a marine system that creates a jet of water for propulsion.
The mechanical arrangement may be a ducted propeller with nozzle, or a centrifugal pump and nozzle. The jet can reach a speed up to 68 km/h
The first functioning pump-jet engine was created by New Zealand inventor, Bill Hamilton (engineer), as early as in 1954.
Pump jets have some advantages over bare propellers for certain applications, usually related to requirements for high-speed or shallow-draft operations, etc. These include: