Pump-jet

Plates, similar to rudders, can be attached to the nozzle in order to redirect the water flow port and starboard.

In a way, this is similar to the principles of air thrust vectoring, a technique which has long been used in launch vehicles (rockets and missiles) then later in military jet-powered aircraft.

An axial-flow waterjet's pressure is increased by diffusing the flow as it passes through the impeller blades and stator vanes.

Mixed flow designs produce lower volumes of water at high velocity making them suited for small to moderate craft sizes and higher speeds.

[2] Pump jets have some advantages over bare propellers for certain applications, usually related to requirements for high-speed or shallow-draft operations.

[5] On December 3, 1787, inventor James Rumsey demonstrated a water-jet propelled boat using a steam-powered pump to drive a stream of water from the stern.

[7][8][9] On December 21, 1833, Irish engineer John Howard Kyan received a UK patent for propelling ships by a jet of water ejected from the stern.

Examples of ships using pumpjets are the Car Nicobar-class patrol vessels, the Hamina-class missile boats, Valour-class frigates, the Stena high-speed sea service ferries, the Royal Navy Swiftsure, Trafalgar and Astute-class submarines, as well as the United States Seawolf and Virginia-classes, and the Russian Borei-class submarines.