Published online by Cambridge University Press: 26 April 2006
It is shown that the linear and nonlinear exciting force coefficients, the added mass and radiation damping matrices, and the far-field wave amplitude (reflection and transmission coefficients in the two-dimensional case) can all be written as stationary values of well-defined functionals. As a consequence these quantities can be accurately determined with relatively crude approximations for the diffraction and radiation potentials. Numerical experiments confirm this feature: by inverting a 4 × 4 real symmetric matrix the results obtained by Vugts (1968), who computed the added mass and radiation damping matrices for several different geometries, were recovered over the whole range of frequencies.