Abstract: A lateral thrust control unit for watercrafts having a pair of tunnels which are directed transversely to the longitudinal axis thereof. Each of the tunnels extend from one side of the watercraft to the oppositely positioned side of the watercraft and have at least one drivable propeller therein. At least one pressure-compensating channel is provided near the tunnels and connects at least one of the zones of differing pressure fields created on the sidewalls of the watercraft as the watercraft moves simultaneously longitudinally and laterally to the pressure field of different potential to equalize the pressure differential therebetween and to reduce the resistance to the lateral movement. The pressure-compensating channels do not have any propulsion devices therein.

Abstract: Propeller arrangement for marine vessels. A small supplemental and independently drivable propeller is mounted for swivelling in a horizontal plane and is preferably positioned in fore-and-aft alignment with at least one main propeller and slightly above same. Preferably the supplemental propeller is positioned ahead of such main propeller a distance equal to at least three-quarters of the diameter of the blade tip circle of the supplemental propeller. The blade tip circle of the supplemental propeller, when projected onto a common transverse plane may lie wholly within the correspondingly projected blade tip circle of the main propeller or it may extend partially out therefrom. The arrangement is adaptable to a variety of specific propeller arrangements including offsetting or angularly positioning the thrust line of the main propeller to counteract the turning moment of propeller torque and is further adaptable for use with single or multiple screw vessels.

Abstract: An amphibious vehicle, normally of tracked land drive, having outboard drive device tiltable for removal from drive position when not in use. There is provided a self-contained water drive device comprising a motor and propeller unit which is tiltably mounted at the stern of the vehicle, the tilting being either longitudinally or transversely as desired. Power and latch devices are provided for tilting and holding the water drive device out of operating position. Other latch structure is provided including automatic control if desired, for holding the water drive device in operating position.