Abstract

An apparatus for mounting a jibsail and a mainsail on a sloop, the structure including a step assembly bedded to the hull and supporting conventional roller and ball bearings; a mast spreading the mainsail; a generally horizontal boom located close above deck and rotating freely about the step; a forespar rotatable about its own axis and extending from high up on the mast to said boom, spreading the jibsail; and rigging connecting the jib and mainsail with said boom. The spars, sails, and cord rigging are freely rotatable on the bearings as a unit about the step as the wind deviates in direction. The rotatable spar-frame allows the sails to respond directly and accurately to shifting winds without requiring repeated manual adjustments, so that the orientations of the sails with respect to the direction of the apparent wind may be voluntarily set, and once set remain constant while the sails operate below stall, in order, first, to provide maximum thrust with minimum drag for sailing to windward and, second, to provide for automatic going about and jibing and sailing on any possible point by manning only the helm.