Prediction of Drift Forces on Twin Hull Bodies in Waves.

Abstract : A theoretical method is presented to predict the steady mean surge and sway forces and roll and yaw moments on floating twin-hull ships in waves. The steady mean forces and moments are derived by utilizing the conservation of momentum of the fluid surrounding the body. The associated velocity potentials are obtained by the strip approximation. Numerical results are presented in graphs and pertinent discussions are made. It is found that the maximum magnitude of the drift force on SWATH ships would be greater than that of equivalent displacement monohull ships and the mean heel angle induced by waves could be significant for SWATH ships. (Author)