DieselShip's Online Content Library

Q7. A ship 140 m long has a total displacement of 21750 tonne in sea water of density 1025 kg/m³. To maintain a speed of 16.5 knots in the above condition on trials, a shaft power of 7800 kW is required.

SCF for trial condition = 1.08

SCF for service condition = 1.24

Quasi-propulsive coefficient (QPC) = 0.69

Transmission losses = 3%

Wetted surface area (m2) = 2.57

Using the information given above, calculate the shaft power required in service for a geometrically similar ship of 26750 tonne load displacement operating at the corresponding speed. (16)

Note: The frictional coefficient for the 21750 tonne ship in sea water is 1.415

The frictional coefficient for the 26750 tonne ship in sea water is 1.413

Speed is in m/s and speed index n = 1.825.