Hydrofoil sailing craft

Claim 2

In a hydrofoil trimaran, a central hull and a pair of pontoon hulls symmetrically disposed on opposite sides of the central hull and spaced therefrom and sail propulsion means, a bow hydrofoil truss structure having a symmetrically disposed dihedral foil element with oppositely inclined lifting surfaces, with strut means, said structure being pivotally mounted upon the opposite sides of the central hull and the pontoon hulls above the normal water line of said hulls on a substantially common pivotal axis, means for securing the truss structure in a generally vertical plane with lifting surfaces inclined to provide a positive angle of attack and positive lift, a lateral hydrofoil unit applied to each of the pontoon hulls, having lifting foils inclined outwardly and upwardly, and laterally of the center of thrust of the sail propulsion means, and a stern foil unit having lifting foils.

Claim 3

A trimaran as set forth in claim 1 wherein the stern foil unit includes steering elements.

Claim 4

A trimaran as set forth in claim 1 wherein the lateral hydrofoil units are secured to the pontoon hulls at three points.

Claim 5

A trimaran as set forth in claim 1, wherein the bow hydrofoil is retractable to a position above the waterline.

Claim 6

A trimaran as set forth in claim 3, wherein the lateral units are secured to the pontoon hulls on a pivotal axis extending generally fore and aft at two of the points, and each unit is retractable by movement about said axis upon disconnecting the unit from its third point.

Claim 7

A trimaran as set forth in claim 1 wherein the foil elements are of a NACA 16- 510 section.

Claim 8

A combination rudder and stern hydrofoil for a water craft comprising a rectangular frame having transverse members adapted to be pivoted centrally in gudgeons at the stern of a water craft, and having spaced side members extending substantially vertical, a pair of rudder blades, each having a pivotal connection to the frame side members on either side of the frame, and each blade having a first rudder blade portion for normal displacement navigation extending to one side of the pivotal connection a sufficient distance so as to act as rudder blades when extending downwardly from said pivot and into and below the waterline, and a second rudder blade portion extending from the other side of said pivotal connection a greater length than said first named portions, transverse hydrofoil means connecting said second rudder blade portions, said hydrofoil means and second portions being adapted to lift the stern of a water craft when underway and when extending downwardly from the pivotal connections, and projecting below the waterline, and means for locking the blades to the frame with first named portions extending below the waterline or the second named portions extending below the waterline.

Claim 9

A combination rudder and stern hydrofoil for a water craft comprising a rectangular frame having transverse members adapted to be pivoted centrally in gudgeons at the stern of a water craft, and having spaced side members extending substantially vertical, a pair of rudder blades, each having a pivotal connection to the frame side members on either side of the frame, and each blade having a first rudder blade portion for normal displacement navigation extending to one side of the pivotal connection a sufficient distance so as to act as rudder blades when extending downwardly from said pivot and into and below the waterline, and a second rudder blade portion extending from the other side of said pivotal connection a greater length than said first named portions, transverse hydrofoil means connecting said second rudder blade portions, said hydrofoil means and second portions being adapted to lift the stern of a water craft when underway and when extending downwardly from the pivotal connections, and projecting below the waterline, and means for locking the blades to the frame with first named portions extending below the waterline or the second named portions extending below the waterline.

Claim 10

A rudder and stern hydrofoil as seT forth in claim 7, wherein the spacing between the blades is such as to permit the first blade portions to clear the stern of a water craft to which the rectangular frame is attached.

Claim 11

A trimaran as set forth in claim 1 wherein the lateral hydrofoil units and the foils thereof are provided with sweep in the order of 10* to 15* directed aft as the foils come up to emerge through the water''s surface.

Claim 12

A trimaran as set forth in claim 1 wherein the lifting surfaces of the bow hydrofoil truss structure have sweep in the order of 10* to 15* directed aft as the lifting surfaces come up to emerge through the water''s surface.

Claim 13

A trimaran as set forth in claim 1 wherein the lateral hydrofoil units and the foils thereof, and the lifting surfaces of the bow hydrofoil truss structure have sweep in the order of 10* to 15* directed aft as the foils and lifting surfaces come up to emerge through the water''s surface.

Claim 14

In a multi-hull sailing vessel having sail propulsion means, and having spaced pontoon hulls, a lateral hydrofoil unit applied to each pontoon having foils inclined outwardly and upwardly and laterally of the center of thrust of the sail propulsion means, and wherein the units, and the foils thereof have sweep in the order of 10* to 15* directed aft as the foils come up to emerge through the water''s surface, wherein the units are secured to the pontoon hulls at three points, and wherein each of the lateral units are pivotally secured to the hulls at two spaced points disposed on a pivotal axis extending generally fore and aft, and each unit is retractable by movement about said axis upon disconnecting the unit from a third point.

Claim 15

In a multi-hull sailing vessel having sail propulsion means, and having spaced pontoon hulls, a lateral hydrofoil unit applied to each pontoon having foils inclined outwardly and upwardly and laterally of the center of thrust of the sail propulsion means, and wherein the units, and the foils thereof have sweep in the order of 10* to 15* directed aft as the foils come up to emerge through the water''s surface, wherein the units are secured to the pontoon hulls at three points, and wherein each of the lateral units are pivotally secured to the hulls at two spaced points disposed on a pivotal axis extending generally fore and aft, and each unit is retractable by movement about said axis upon disconnecting the unit from a third point.