| 摘要 |
High performance of a sailboard is achieved over a wider range of wind and water conditions by providing a hull having two or more planing surfaces which may differ in shape and/or aspect ratio. Drag due to suction at steps between planing surfaces is reduced by venting to the air. Cusp shaping of the respective planing surfaces can reduce and stabilize the angle of attack at the displacement/planing transition without causing fore-and-aft pitching effects known as porpoising. By confining water under the planing surfaces to reduce lateral outflow thereof through increased downward curvature of the bottom of the board, winglets, asymmetrical fins, fences and the like, the effective width and aspect ratio of the wetted area may be altered beyond that of the actual geometry of the planing surfaces to further increase lift and reduce drag while providing additional sources of lift at displacement, transitional and planing speeds. Steps and/or cambered shapes of the planing surface may be used to dramatically further reduce wetted area and further increase effective aspect ratio.
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