Conventional planing motorboats, when running relatively fast, are supported mainly by dynamic lift. However, these boats are not configured so that the dynamic lift is produced efficiently. Therefore they have unnecessarily high drag. The hull drag of planing motorboats can be approximately halved by incorporating the features that produce dynamic lift effectively. The required features are longitudinal camber curvature of the planing area, appropriate size of the planing area for the design speed and weight, operation at optimum angle of attack, and relatively high aspect ratio of the planing area. A planing motorboat configuration that incorporates thosefeatures, the Dynaplane, has been developed, and its superior performance has been validated by the testing of models and prototype boats.Calculations of the resistance of Dynaplane-type boats for a wide range of values of the significant design parameters have now been made. The calculations show that only the single factor of deadrise angle significantly affects Dynaplane resistance at planing speeds. Accordingly it has been possible to give a method for calculating planing-speed resistance of Dynaplane type boats, quickly and easily, for wide ranges of values of deadrise angle, weight, size, and speed.
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