Stepped Planing Hull Investigation Power And （加强规划权力和船体调查）.pdfVIP

1 Stepped Planing Hull Investigation William R. Garland, Midshipman First Class, United States Naval Academy When a vessel travels at high speeds and enters the planing regime of operation, it experiences hydrodynamic forces that provide the necessary lift for it to operate efficiently. The lift forces on the after portion of the hull, however, are almost negligible, and therefore the after portion of the hull does little more than add to the frictional resistance. By introducing a step (or multiple steps) into the hull bottom at the proper location and subsequently ensuring that the flow separates from the hull at the step, a substantial decrease in frictional resistance is realized, provided that the region aft of the step is sufficiently ventilated. By testing both an unstepped and an adjustable stepped version of a generic, 5-foot, prismatic planing boat model at the U.S. Naval Academy Hydromechanics Laboratory, more insight was gained regarding the advantages and disadvantages of operating stepped hulls across the range of speeds. Introduction displacement vessels at high speeds. Planing The constant design balance between range, craft are less efficient at low speeds but much speed, and payload will always present more efficient at high speeds. Planing hulls are significant obstacles to Naval Architects in their designed to create positive dynamic pressures quest for optimally efficient designs. Hull (lift) so that the draft decreases when the speed shapes optimized for low speeds and designed to increases. This enables them to ride higher on operate in the displacement regime have narrow the waves they create, thus avoiding the or pointed sterns that make the hull squat at high increases in drag associated with high-speed speeds. Displacemen