This method relates the global wave excitation to the sectional added mass and damping coefficients. The sectional wave excitation forces, required for the loads analysis are not computed directly. Both wave heave excitation force and wave pitch excitation moment may be evaluated with or without transom terms. At present, the head seas approximation is used. The excitation can be evaluated using complex notation in order to obtain the magnitude and phase.

It should be noted that these equations are estimates for head seas only. In addition the wave attenuation with depth is approximated by the  term in the expressions below. Again this is a fairly crude approximation valid for ‘normal’ section shapes only.

the transom terms being as follows:

The additional variables are defined as follows: