The measurement and the analysis of the unsteady waves generated by a ship model making sway, yaw and roll motions and simultaneously running with a constant forward velocity are proposed for getting the energy flux of the waves and deriving the wave damping coefficients for those motions. The damping coefficients derived do not include the damping effects caused by the dissipation of energy due to the viscosity of water. Accordingly they can be directly compared with the predictions by the Strip theory.
Some examples are presented for the damping coefficients obtained by the wave measurements. The wave damping coefficient for roll is confirmed to be independent of forward speed for greater Ω=Vω/g. and can be predicted fairly well by the Strip theory. The accuracy of the theoretical predictions are revealed, however, to be questionable for the damping coefficient of yaw.