Hydrofoil system for mono-hull sailboats - AU2007237129

Last Updated: 19/05/2015

CLAIMS 1. A monohull sailing vessel comprising: (a) a hull with a longitudinal dimension, a bow, a stern, a port side, and a starboard side; 5 (b) at least one mast for supporting at least one sail, the mast coupled to the hull; (c) a lifting hydrofoil having a stowed position in which the lifting hydrofoil is disposed inward of the hull and a deployed position in which the lifting hydrofoil is adapted to extend outward of a leeward side of the hull and in the water supporting the vessel; 10 (d) wherein the lifting hydrofoil has an aspect ratio that is greater than about 2:1; (e) wherein the lifting hydrofoil when in the deployed position is oriented at a predetermined angle of attack to a fore and aft plane of the vessel, the predetermined angle of attack being between about 2 and 6 degrees; (f) wherein the lifting hydrofoil when in the deployed position is oriented at a 15 mean angle of between about 5 and 20 degrees to a horizontal plane when the vessel is in a non-heeled state so that the lifting hydrofoil is substantially parallel with the water plane when the vessel is heeled to a normal optimum sailing heel angle; (g) wherein the lifting hydrofoil when in the deployed position has a projected 20 area adapted provide a righting moment tending to counteract a heeling moment applied by the sail of the vessel and a lifting force for partially but not fully lifting the vessel out of the water; (h) wherein the lifting hydrofoil has an exposed span that is greater than about 7% of a height of the tallest mast of the vessel, the height measured from the 25 water plane; and (i) an actuation assembly for moving the lifting hydrofoil between the stowed position and the deployed position. 21WO 2007/116318 PCT/IB2007/001455 2. The monohull sailing vessel of Claim 1, wherein the lifting hydrofoil is coupled to the vessel such that the predetermined angle of attack of the lifting hydrofoil when in the deployed position and while the vessel is underway is static and not adapted for continuous adjustment to selectively control the lifting force produced 5 by the lifting hydrofoil. 3. The monohull sailing vessel of Claim 1, wherein the lifting hydrofoil is coupled to the vessel such that the mean angle of the lifting hydrofoil relative to the horizontal plane when in the deployed position and while the vessel is underway is static and not adapted for continuous adjustment to selectively control the 10 lifting force produced by the lifting hydrofoil. 4. The monohull sailing vessel of Claim 1, wherein the lifting hydrofoil is coupled to the vessel such that the projected area of the lifting hydrofoil when in the deployed position and while the vessel is underway is static and not adapted for continuous adjustment to selectively control the lifting force produced by the 15 lifting hydrofoil. 5. The monohull sailing vessel of Claim 1, wherein the lifting hydrofoil is coupled to the vessel such that the angle of attack, the designed mean angle, and the projected area of the lifting hydrofoil when in the deployed position are static and not adapted for continuous adjustment to selectively control the lifting force 20 produced by the lifting hydrofoil while the vessel is underway. 6. The monohull sailing vessel of Claim 1, wherein the lifting hydrofoil is positioned along the longitudinal dimension to be within a predetermined distance of a centre of gravity of the vessel when in sailing trim, the predetermined distance being less than or equal to 15% of a length over all (LOA) of the vessel. 25 7. The monohull sailing vessel of Claim 6, wherein the lifting hydrofoil is positioned aft of the centre of gravity of the vessel. 8. The monohull sailing vessel of Claim 1, wherein the exposed span of the lifting hydrofoil is greater than about 7% and less than about 20% of the height of the tallest mast of the vessel, the height measured from the water plane. 22WO 2007/116318 PCT/IB2007/001455 9. The monohull sailing vessel of Claim 1, wherein the hull includes a channel disposed on the starboard side of the hull extending from a point below the waterline to a point above the waterline, the channel adapted to receive the lifting hydrofoil when the lifting hydrofoil is in the stowed position such that the bottom 5 surface of the lifting hydrofoil is substantially flush with the hull. 10. The monohull sailing vessel of Claim 1, wherein the aspect ratio of the lifting hydrofoil is greater than about 4:1. 11. The monohull sailing vessel of Claim 1, wherein the exposed span of the lifting hydrofoil is between about 30% and 150% of a beam of the vessel measured at 10 the waterline. 12. The monohull sailing vessel of Claim 1, wherein the aspect ratio of the lifting hydrofoil is between about 3:1 and 8:1. 13. The monohull sailing vessel of Claim 1, wherein the static angle of attack of the lifting hydrofoil is between about 3 and 5 degrees when in the deployed position. 15 14. The monohull sailing vessel of Claim 1, wherein the actuation assembly is adapted to rotate the lifting hydrofoil from the stowed position to the deployed position. 15. The monohull sailing vessel of Claim 1, wherein the actuation assembly is adapted to move the lifting hydrofoil athwartships from a starboard extended 20 position in which a starboard end of the lifting hydrofoil is positioned outward of the hull and a port end of the lifting hydrofoil is positioned inward of the hull and a port extended position in which the port end of the lifting hydrofoil is positioned outward of the hull and the starboard end of the lifting hydrofoil is positioned inward of the hull. 25 16. The monohull sailing vessel of Claim 1, wherein the lifting hydrofoil is oriented such that when the lifting hydrofoil is in the deployed position with the monohull sailing vessel in an unheeled state, a distal end of the lifting hydrofoil extends above the water plane. 23WO 2007/116318 PCT/IB2007/001455 17. The monohull sailing vessel of Claim 1, wherein the lifting hydrofoil is held in the deployed position by a load release mechanism adapted to release the lifting hydrofoil from the deployed position when a load upon the lifting hydrofoil exceeds a predetermined level. 5 18. The monohull sailing vessel of Claim 1, wherein the lifting hydrofoil is rotated between the deployed and stowed positions about a pivot axis that is oriented substantially parallel to the longitudinal dimension of the vessel. 19. The monohull sailing vessel of Claim 1, wherein the lifting hydrofoil is a housed in a slot in the hull that extends from the starboard side to the port side of the hull, 10 and wherein the lifting hydrofoil is double ended such that the lifting hydrofoil is adapted to be deployed on either the starboard side or the port side of the hull by moving the lifting hydrofoil athwartship in the slot. 20. The monohull sailing vessel of Claim 1, wherein the lifting hydrofoil is bowed in the athwartship direction such that when the lifting hydrofoil is in the deployed 15 position and the vessel in a non-heeled state, a distal end of the lifting hydrofoil is at a greater elevation than a proximal end of the lifting hydrofoil. 21. The monohull sailing vessel of Claim 1, wherein the vessel includes at least one lifting hydrofoil adapted to extend from the port side when in the deployed position and at least one lifting hydrofoil adapted to extend from the starboard 20 side of the hull in a different longitudinal position from the lifting hydrofoil on the starboard side such that the port and starboard lifting hydrofoils are offset from one another and the lifting hydrofoils are asymmetrically disposed about the vessel. 22. The monohull sailing vessel of Claim 1, wherein the lifting hydrofoil, when in the 25 deployed position, is in a swept back orientation such that the lifting hydrofoil is inclined relative to a line oriented perpendicular to a centerline of the boat by a predetermined angle, the predetermined angle being greater than about 5 degrees. 24WO 2007/116318 PCT/IB2007/001455 23. The monohull sailing vessel of Claim 1, wherein the actuation assembly is adapted to move the lifting hydrofoil between the stowed position and the deployed position by simultaneous linear and rotary actuation. 24. The monohull sailing vessel of Claim 1, wherein an intended operation 5 immersion depth of the lifting hydrofoil during operation is between about 50% and 150% of the chord length of the lifting hydrofoil. 10 25