Abstract: The main propulsion and drive system of a merchant vessel such as a freighter or tank vessel, or a military vessel is supplemented by an auxiliary propulsion and drive system that includes at least one, but preferably a pair of auxiliary propellers that flank the main propeller at port and starboard positions and each of which are attached via a drive shaft through a gear train, which can optionally include a clutch mechanism, to an auxiliary motor or motors. In order to reduce the drag when the main propeller is disabled, segments of a wake field modifying propeller duct are mounted for repositioning to form at least a partial housing or cowling that diverts the water over the exterior surface of the duct and minimizes contact with the stationary blades of the main propeller as the vessel moves through the sea when powered by the auxiliary propulsion system.