Abstract: An asymmetrically arranged hydrofoil and propeller system is disclosed for improving the speed and lift of watercraft such as amphibious vehicles. When the vehicle is propelled through water by propellers, a downwash of water from the upper surface of the asymmetrically arranged hydrofoils is intercepted by upwardly moving propeller blades which improve the speed, lift and efficiency of the watercraft.

Abstract: A pair of integrated water propulsion and hydrofoil systems capable of moving through water at speeds of at least 20 miles per hour are disclosed, each hydrofoil system having a hydrofoil and a mounting leg removably secured to a water propulsion system. The mounting legs are supported on opposite sides of the watercraft for moving the hydrofoils between a water mode and a land mode. The water propulsion system may be an inline water jet, and the hydrofoils may be formed from interconnected lightweight hollow beams with power operated flaps on the trailing portions of the hydrofoils for adding more lift when moving at slow speeds through water. The watercraft may be a military amphibious vehicle weighing about 30 tons.