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In a dual-hull watercraft, a separate keel hull and sail hull are connected by a tie line. The sail hull comprises a sail and hull without a keel. The keel hull comprises a keel and hull or a submerged keel. The flexible tie line is coupled to the keel at or near the keel center of effort and is cou

In a dual-hull watercraft, a separate keel hull and sail hull are connected by a tie line. The sail hull comprises a sail and hull without a keel. The keel hull comprises a keel and hull or a submerged keel. The flexible tie line is coupled to the keel at or near the keel center of effort and is coupled to the sail at or near the center of sail effort. During operation, the sail and keel are configured to "toe in" relative to each other, maintaining tension in the tie line allowing the sail and keel to provide for the other's drag. The tie line allows for directional steering of the craft without a rudder, and for controlling the speed of the craft and the heel angles of the sail and keel hulls. Two gliders similarly connected can exploit wind velocity differences and are operable without updrafts.

대표청구항 ▼

[ I claim:] [1.] A watercraft comprising:a buoyant hull comprising a keel hull and sail hull;a sail-foil having a center of effort, said sail-foil coupled to the sail hull and exposed to wind forces;a keel-foil having a center of effort, said keel foil positioned upwind of the sail-foil, said keel-f

[ I claim:] [1.] A watercraft comprising:a buoyant hull comprising a keel hull and sail hull;a sail-foil having a center of effort, said sail-foil coupled to the sail hull and exposed to wind forces;a keel-foil having a center of effort, said keel foil positioned upwind of the sail-foil, said keel-foil coupled to the keel hull and exposed to water forces; anda flexible tie line coupled near the virtual center of effort of the sail-foil and near the virtual center of effort of the keel-foil, said wind forces operating on the sail-foil and said water forces operating on the keel-foil during steady-state sailing, tensioning the tie line coupled therebetween, said water forces being translated through the tensioned tie line to the center of force of the sail-foil, eliminating heeling torque in the watercraft, said tie line having a length which is adjustable for adjusting the distance between said sail-foil and said keel foil and having an orientation which is adjustable for controlling heeling, speed, and direction of sail of said craft.