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For a displacement vessel, that is the usual type of ship, three main types of resistance are considered: that due to wave-making, that due to the pressure of the moving water on the form, often not calculated or measured separately, and that due to friction of moving water on the wetted surface of the hull. These can be split up into more ...
The hull is now starting to climb its own bow wave, and resistance begins to increase at a very high rate. While it is possible to drive a displacement hull faster than a speed-length ratio of 1.34, it is prohibitively expensive to do so. Most large vessels operate at speed-length ratios well below that level, at speed-length ratios of under 1.0.
The fundamental cause of "helm", be it weather or lee, is the relationship of the center of pressure of the sail plan to the center of lateral resistance of the hull. If the center of pressure is astern of the center of lateral resistance, the result is a weather helm, the tendency of the vessel to want to turn into the wind.
The displacement hull tends to stay more level and "plow through" the wave. This hull shape was further developed as a torpedo boat (later called Schnellboot ) of the Reichsmarine or German Navy. The first of the torpedo boats (the British called them " E-Boats ") was UZ (S).16 (which was a development of the motor yacht Oheka II , itself ...
Hull speed can be calculated by the following formula: where is the length of the waterline in feet, and is the hull speed of the vessel in knots. If the length of waterline is given in metres and desired hull speed in knots, the coefficient is 2.43 kn·m −½.
Forward resistance comprises the types of drag that impede a sailboat's speed through water (or an ice boat's speed over the surface) include components of parasitic drag, consisting primarily of form drag, which arises because of the shape of the hull, and skin friction, which arises from the friction of the water (for boats) or air (for ice ...
A velocity prediction program (VPP) is a computer program which solves for the performance of a sailing yacht in various wind conditions by balancing hull and sail forces. VPPs are used by yacht designers, boat builders, model testers, sailors, sailmakers, also America's Cup teams, to predict the performance of a sailboat before it has been built or prior to major modifications.
When boat speed increases and waves are generated the resistance is dependent on several design factors, particularly hull displacement to length and hull separation to length ratio, it is a non trivial resistance curve with many small peaks as wave trains at various speeds combine and cancel [32] [33] For powered catamarans, this implies ...