Patent ID: 8720354

Claim:
A watercraft comprising a hull having a mast with sail, an aft rudder and a hydrofoil projecting below the bottom of the hull, said watercraft further comprising means pivotally connecting each hydrofoil to the hull enabling the said hydrofoil to pitch on a pivot axis which is essentially perpendicular to the longitudinal axis of the hull, said hydrofoils having a vertical part which produces lateral forces to accelerate the boat in turns and resist lateral forces from the sail, and a vertical portion which curves into the horizontal portion which produces vertical lift, means controlling the angle of incidence of the hydrofoil comprising a trailing sensor arm, said sensor arm being carried on a pivot in proximity to the fore end of the hull, said sensor being dragged behind the pivot, and means connecting said sensor arm to said hydrofoil whereby when the hull is low in the water the sensor arm is constrained to pitch down, and when the hull is too high, the sensor arm pitches up, and when the sensor arm pitches down, the hydrofoil pitches up and when the sensor arm pitches up, the hydrofoil pitches down.