Lifting-sail boat apparatus and method
OwnerDavid Allen Estabrooksinventor
Life of this patent
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Abstract
A lifting-sail rig and method comprising airfoils, or efficient aerodynamically shaped leading edge soft sails, supported by an improved non-interfering fixed mast rig positioned away from the lifting-sail for increased aerodynamic efficiency and ease of sail or airfoil control. Stable sailboat performance is achieved at a higher speed for multihulls and widened beam monohulls for supporting the lifting-sail rig. The improved lifting-sail rig balances the large wind driven forces that have resulted in the capsizing of conventional monohull sailboats, and the pitch poling of multihulls.
Claims14
A lifting sail craft having a hull, a mast, and a sail supported in the upper vicinity of the top of the mast, comprising
- means for supporting a luff spar of the sail having an upper end and a lower end on a sprit member fixed to the mast without aerodynamic interference with the sail in the upper vicinity of the top of the mast;
- means for articulately connecting the luff spar to the sprit member to permit the luff spar to tilt with respect to the mast and to rotate the luff spar with the sail on changing course with respect to the wind, the connecting means being universally coupled to the mid region of the sprit member, and being attached near the upper end of the luff spar at a point above the center of effort of the sail and the center of lateral resistance of the hull;
- means for directly connecting the mid region of the luff spar with a fore member to the end region of the sprit member for controlling the rake angle of the luff spar and the sail with respect the mast, in response to dynamic wind pressure on the sail, wherein upon the dynamic means to incline the sail at an upward angle to the mast line, the center of effort of the sail passes thru the center of lateral resistance of the hull, the sail exerts substantially no overturning effort on the hull;
- means for controlling the tilt angle of the luff spar with respect to the mast and means for controlling the rotation of the luff spar with respect to the wind direction.
A lifting sail craft having a hull, a mast, and a sail supported in the upper vicinity of the top of the mast, comprising
- means for supporting a luff spar of the sail having an upper end and a lower end on a sprit member fixed to the mast without aerodynamic interference with the sail in the upper vicinity of the top of the mast;
- means for articulately connecting the luff spar to the sprit member to permit the luff spar to tilt with respect to the mast and to rotate the luff spar with the sail on changing course with respect to the wind, the connecting means being universally coupled to the mid region of the sprit member, and being attached near the upper end of the luff spar at a point above the center of effort of the sail and the center of lateral resistance of the hull;
- means for directly connecting the mid region of the luff spar with a fore member to the end region of the sprit member for controlling the rake angle of the luff spar and the sail with respect the mast, in response to dynamic wind pressure on the sail, wherein upon the dynamic means to incline the sail at an upward angle to the mast line.
Dependencies are inferred from the claim text.