| 摘要 |
The present invention over-comes the prior art deficiencies by, in part, defining a hull bottom that decreases the total resistance and thereby reduces the propulsion power needed to propel a boat of a certain weight to a given speed. The invention separates the functions of the planing process resulting in a hull with staged longitudinal steps wherein each step consists of a fully defined hull underbody with a chine and bow and stern. Each intermediate chine describes a supplemental planing surface which is designed to lift the hull dynamically and to position the hull on the next narrower step that supports the weight of the boat and creates the forces needed to further lift the hull to the next narrower chine in two or more stages depending upon the size and weight of the boat to lift the hull to the central planing surface to achieve the desired top speed. The hull for each step is described by its chine, hull bottom, deadrise angle, bow and stern dimensions optimized to the "ideal beam"(Ref. 7) to cover the range of speed of its stage of supplemental planing surfaces in the planing process by controlling the trim angle and vertical rise in the center of gravity. The hull bottom of each supplemental and central planing stage is separated by a vertical step extending longitudinally from bow to stern with the deadrise angle of the hull bottom of each step equal to or greater than the lower narrower hull stage below it. As a result the trim angle of the speed range for each stage can be optimized to fall in the range of 3.5 to 5 degrees to provide the least total resistance (Ref 5) (the combined wave making and friction resistance) over the range of operation for the hull of each stage and for the overall operating range covering all stages from rest to top speed. The number of supplemental planing surface stages, if more than one, will depend primarily upon the top speed to be attained and the overall length and width of the boat. An intermediate lower speed for long term operation as a cruising speed may be selected to dictate a staging point to assure optimized efficiency at this intermediate stage; such as, to optimize the efficiency at the cruise rating of the propulsion system for extended range (based upon the fuel tankage capacity).
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