Abstract: The invention is a rigging (9) for a wind propelled craft (8). The rigging (9) comprises a flexible sail (10) of two substantially identical flexible sail portions (80, 82) each having a leach (18) and a luff (20). Elongated battens (92) are in contact with the flexible sail portions (80, 82). A control rod (32) has the battens (92) and luffs of the sail portions (80, 82) rotatably attached so that the perpendicular distance between the sail portions (80, 82) varies wherein angular displacement of the control rod (32) with respect to the boom causes the battens (92) to be compressed along their length so as to bend one of the sail portions (80) to increase the camber thereof and causes the battens (92) of the other sail portions (82) to be tensioned along their length so as to partly straighten the other sail portion (82) which decreases the perpendicular distance between the sail portions (80, 82) resulting in asymmetry of the aerofoil.