Author(s)

N. Fonseca & C. Guedes Soares

Abstract

The time domain description of the vertical motions of a ship travelling at constant forward speed is studied. The hydrodynamic forces are represented by infinite frequency added mass, convolution integrals and restoring force coefficients which are obtained from Fourier transforms of the frequency domain solutions. The exciting forces are calculated in the frequency domain. The hydrostatic forces are evaluated both around the mean equilibrium position and over the instantaneous wetted surface in order to assess the effect of the non-linearity of these forces. A strip theory is used to obtain a numerical solution to the problem. Results of heave and pitch motions are presented for a large containership and a tanker in head waves, and comparisons are made between the solutions for linear and for

Keywords