The speed of a conventional sailboat is limited by a phenomenon referred to as “heeling.” Wind produces a force or thrust generally normal to the sail surface, and the lateral component of this force is resisted by an opposing force applied by water to the keel of the boat. Such forces create a moment that tilts, and can potentially overturn, a boat. A common way to compensate for heeling is to employ a heavy keel that counterbalances the heeling moments to some degree. This has the drawback, however, of increasing the weight of the boat and causing the hull to ride deeper in the water, increasing drag. Another form of compensation is to locate passengers on the windward side of the sail or to have passengers lean from the windward side of the boat over the water. However, the tendency to heel increases with wind force and ultimately limits the speed at which the boat can be safely operated despite compensating measures.
A class of sailing craft has been proposed in which rigging supports the sail assembly so as to generate a propelling force substantially free of heeling moments. In such a craft, a sail is supported in such a manner that the thrust created by wind action and the corresponding keel force are substantially aligned and directed through a single point. Proposals for sail craft embodying such an operating principle are to be found in U.S. Pat. No. 1,670,936 to McIntyre et al, U.S. Pat. No. 4,068,607 to Harmon, U.S. Pat. No. 4,809,629 to Martinmaas, U.S. Pat. No. 6,732,670 Rayner, and International Publication No. WO 01/00486 of inventor Stenros. Such a sail arrangement will also tend to lift the craft, reducing displacement and hull drag. Despite obvious advantages, such sailing craft remain relatively unused, and it is an object of the present invention to provide a practical implementation of a sailboat belonging to this class of sailing craft.