Q16. A ship model of length 6 m has a wetted surface area of 5.75 m2 and is tested in water of Density 1000 kg/m3.
The test results give the values of residuary resistance for a range of model speeds as shown in Table Q5.
(a) (i) Plot a curve of model residuary resistance against model speed.
(ii) Comment on the shape of this curve.
(b) For a geometrically similar ship of length 140 m operating in sea water of density 1025 kg/m3 at service speed of 17.25 knots, the following data is applicable:
Appendage allowance = 8%
Weather allowance = 15%
Quasi-propulsive coefficient (QPC) = 0.69
Transmission losses = 3%
Determine the shaft power required for the ship at it’s service speed.
Note: The frictional coefficient for the ship in sea water is 1.415
Speed in m/s with index (n) for ship and model 1.825
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