Subcritical and Supercritical Operation of Ships in Waves and the Coincidence of Maximum Damping

Abstract

Several papers by Lewis [1, 2, 3]3 have discussed the relationship between hull form and critical and supercritical operation in ahead seas. The present paper extends consideration to overtaking and following seas and defines subcritical, critical, and supercritical zones of operations in ahead, overtaking, and following seas. A region is pointed out where unorthodox ships may be designed to operate where resonant and near-resonant conditions with all important wave components may be almost entirely avoided throughout a substantial range of speeds in ahead and overtaking seas. In the limited case where resonance is encountered with important wave components in this region, it is shown that maximum wave damping might be simultaneously experienced. In the course of developing this subject, it was found that the theoretical condition for maximum wave damping is identical in overtaking seas with a particularly significant case of resonance.