Automatic hydrofoil control system for watercraft

Claim 1

IN A WATERCRAFT OF THE TYPE WHOSE HULL IS SUPPORTED BY AT LEAST ONE AT LEAST PARTIALLY WATER-SUBMERGED FOIL EXTENDING SUBSTANTIALLY TRANSVERSELY TO THE LONGITUDINAL AXIS OF THE HULL, IN COMBINATION, AT LEAST ONE FOIL HAVING A SUCTION SIDE AND DEFINING THEREWITHIN AT LEAST ONE INTERNAL SPACE, SAID FOIL FORMED WITH AIR DISCHARGE APERTURE MEANS BETWEEN SAID SUCTION SIDE AND SAID INTERNAL SPACE; AND A CONTROL SYSTEM FOR AUTOMATICALLY ADJUSTING THE DISTANCE BETWEEN THE FOIL AND THE WATER SURFACE, SAID SYSTEM COMPRISING AT LEAST ONE CONTROL MEMBER DEFINING THEREWITHIN AT LEAST ONE INTERNAL SPACE IN COMMUNICATION WITH THE INTERNAL SPACE OF SAID FOIL, SAID CONTROL MEMBER FORMED WITH AIR INTAKE ORIFICE MEANS DISPOSED IN THE AREA OF SUBPRESSURE PRODUCED BY THE WATER FLOW AT THE PROFILE OF THE CONTROL MEMBER AND LOCATED IN PART ABOVE AND IN PART BELOW THE NORMAL LEVEL OF THE WATER SURFACE WHEN THE WATERCRAFT IS IN MOTION, THE LOW-PRESSURE AREA DEVELOPING AT THE SUCTION SIDE OF SAID FOIL CAUSING THE AIR ENTERING THROUGH THE ORIFICE MEANS DISPOSED ABOVE THE WATER SURFACE TO FLOW FROM THE INTERNAL SPACE OF SAID CONTROL MEMBER INTO THE INTERNAL SPACE OF SAID FOIL AND TO BE DISCHARGED THROUGH SAID APERTURE MEANS, THE RATIO OF COMBINED CROSS-SECTIONAL AREA OF ORIFICES ABOVE THE WATER SURFACE TO THE COMBINED CROSS-SECTIONAL AREA OF ORIFICES BELOW THE WATER SURFACE DETERMINING THE EXTENT TO WHICH THE AIR DISCHARGED THROUGH SAID APERTURE MEANS AFFECTS THE LIFT FORCE UPON SAID FOIL.