pumpjet

Enclosed marine propeller

A pumpjet is a marine propulsion system that draws water through an intake and expels it at high pressure through a nozzle, rather than using an exposed propeller.

Pumpjets are quieter and safer than traditional propellers, making them common on personal watercraft, submarines, and vessels operating in shallow water where debris or swimmers might be struck by spinning blades.

mechanism

impeller

Pump's spinning blade assembly

nozzleFlow-directing pipe fitting
shroudBurial cloth or covering
rotorSpinning mechanical assembly

stator · ducted · waterjet · thruster · inlet · outlet · housing · diffuser · venturi · intake

advantages

quiet

Lacking in sound

stealthSecret, undetected movement
maneuverableCapable of being steered
efficientProductive without waste

safe · enclosed · protected · responsive · smooth

hydrodynamics

cavitation

Pressure-induced void creation

thrustForceful forward motion
wakePath left in water
streamliningMaking more aerodynamic or efficient

vortex · momentum · swirl · flow · pressure · turbulence · laminar · hydrodynamics · efficiency

submarine

torpedo

Propelled undersea explosive

stealthSecret, undetected movement
nuclearOf atomic energy
underwaterBelow the surface

periscope · sonar · hull · dive · ballast · submersible · submerged · depth · naval · warfare

vessels

hydrofoil

Wing that lifts boats

ferryVessel for scheduled crossings
yachtLarge pleasure vessel
speedboatFast motorized watercraft

tender · amphibious · hovercraft · catamaran · workboat

Opposites

power source type

pumpjetsail

Ship's wind-catching fabric

oar · paddle · rowing · wind power · paddlewheel

Family

pump, jet, pumps, pumped, pumping, jets, jetted, jetting

Familiarity: Top 1,000,000
Profile: Used worldwide · Timeless · Concrete · Rated G