A device that is placed over or behind the propeller of a boat to deflect the vessel's propwash downward. The result is a very effective form of agitation dredging. PDUs are primarily used by salvors to remove mud or sand from shallow water shipwrecks.

plural of propwash deflection unit

Something which deflects something else, especially a stream of fluid or particles. / A diaphragm in a lamp, stove, etc. by which the flame and gases are brought together to improve combustion.

plural of deflector

An instrument that measures the deflection of structures when loads are applied.

The measurement of deflection under applied loads.

plural of deflectometer

Relating to deflectometry.

plural of smoke deflector

(rail transport) a device fitted to either side or on top of the smokebox of some steam locomotives, the purpose of which was to lift smoke clear of the locomotive at speed, so it wouldn't obscure the driver's vision.