Aft hung hydrofoil for reduction of water resistance of partially immersed sailing vessels

A hydrofoil device for reducing wake formation on a partially immersed hull of a single hulled vessel, said hydrofoil device comprising:

• a transverse hydrofoil positioned below the surface of the water when said vessel is in the water, said hydrofoil being capable of a positive angle of attack of between 2 to 8 degrees to the static waterplane, the leading edge of said hydrofoil being between 5 and 15% of the immersed length of the vessel aft of the transom of said vessel, and the upper surface of said hydrofoil being between 5 and 15% of the immersed length of the vessel below the static waterplane of said vessel,
• a strut or multiple struts for attaching said hydrofoil to said vessel,
• a means for attaching said hydrofoil to said strut or struts, and
• a means for attaching said strut or struts to said vessel,
• wherein said vessel is a sailboat and said hydrofoil device is mounted to said sailboat by means of a track device that allows said strut to be moved relative to the vertical axis of the transom of said sailboat such that the transverse axis of said hydrofoil may be more horizontal than when said sailboat is heeled.