Rigging for a wind propelled craft

Rigging for a wind propelled craft comprising:

• a sail comprising two substantially identical flexible sail portions each having a leach and a luff and a foot, each of said leach and said foot being joined at a clew and said leaches of said flexible sail portion being attached together, said sail portions each having a variable camber;
• a plurality of elongated battens each having flexure in at least two dimensions, each of said elongated battens comprising two batten portions one of which is disposed in contact with one of said sail portions and the other of which is disposed in contact with the other of said sail portions;
• a spar comprising a boom and a control rod, said control rod being arranged to be disposed upright and rotatable upon said wind propelled craft, said boom being rotatably attached to said control rod and having said clew of each of said sail portions attached to said boom remotely of said control rod, said control rod having said batten portions of each of said elongated battens and said luff of each of said sail portions pivotally attached to said control rod in spaced apart manner so that a perpendicular distance between said two sail portions adjacent said control rod may be varied;
• and a control means comprising a lever fixed in rotation with said control rod, said lever being capable of angularly displacing said control rod with respect to the boom;
• said sail portion and said elongated battens and said spar forming an aerofoil having a leading edge adjacent the spar and a trailing edge adjacent the leaches of said sail portions, such that angular displacement of the control rod with respect to the boom causes said batten portions in contact with one of said sail portions to be compressed along their length so as to bend said one of said sail portions to increase the camber thereof while causing said batten portions in contact with the other one of said sail portions to be tensioned along their length so as to tend to partly straighten the other one of said sail portions to reduce the camber thereof which decreases the perpendicular distance between said two sail portions adjacent said control rod, the respective bending and straightening of said sail portions resulting in asymmetry of the aerofoil and the spaced apart attachment of luffs to said control rod producing thickness in the aerofoil, said asymmetry and thickness of the aerofoil being dependent on the angular displacement of said lever with respect to the boom.