摘要 |
A sail (20) for a sailing vessel (500) includes a leading spar (22), a coplanar trailing spar (24), and a movable spar (28) disposed between the two. A sheath (30) of sail cloth traversly surrounds the three spars forming a flexible double-sided wing-like structure. When the wind (600) blows against sail (20), movable spar (28) is urged toward the leeward side of sail (20), and transforms that side into the curved or long side of an airfoil, thereby creating a push force (54) which propels the sailing vessel (500).
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