Relating to wingsail craft and wingsails therefor

Abstract

A wingsail assembly in which the pivoting mounting is situated in line with a strengthened portion of the sail assembly such as a strengthened leading edge of a sail element while still retaining the alignment of the axis of pivoting and the center of pressure. A sail assembly is also described in which a locating mechanism, typically in the form of wire stays, a mechanical linkage or a hydraulic system, is arranged to act on opposite sides of a balancing mass, carried by a boom attached to the wingsail assembly and arranged to locate the mass in an approximately horizontal plane. Where the wing or wing section is constructed from spars and ribs where the latter define the aerofoil section of the wing and lie in the direction of air flow, the ribs are conveniently formed from moulded GRP material and include flanges which in selected regions of the periphery of the rib subtend an angle of greater than 90.degree. to the plane of the rib to facilitate removal of the rib from a mould and include other regions in which the flange subtends an angle of 90.degree. to the plane of the rib to facilitate its fixing to a spar. The non 90.degree. angles are conveniently commensurate with the angle of rake of the edge regions of the sail or sail element and are situated at points adjacent the leading or trailing edges of the sail or sail element.