At moderate Froude number, Seakeeper results have been computed with and without additional transom terms. These terms significantly increase the damping, particularly for pitch. The terms are suggested by Salvesen et al. (1970) because the Strip Theory formulation assumes that the sectional added mass and damping tend to zero at the vessel bow and stern. However, for high-speed semi-displacement forms which have transom areas which are often a large proportion of the maximum cross sectional area, it is felt, that the transom terms provide an excessive amount of extra damping and some judgement, on the part of the designer, is required to determine whether transom terms should be included or not.

For heave at Froude number = 0.53, Figures 3, 6 and 9, Seakeeper predictions including transom terms are closest to the experiment results. However, for pitch, results without transom terms are more accurate. In all cases the Seakeeper predictions show good correlation with the experiment results for the two catamaran configurations. The experimental results for the demihull in isolation (monohull) are slightly reduced when compared with those of the two catamaran configurations.

Seakeeper tends to over predict the frequency at which the resonant peak occurs, and this is more so for the predictions of pitch response. As might be expected, the discrepancies between predictions and experiments reduce for the more slender models (going from model 4b to 6b). However, in general the predictions at F_n = 0.53 are quite reasonable.