WAVE TANK TESTING AND THE CAPSIZABILITY OF HULLS

We study the capsize of model ships excited by the naturally propagati ng wavefront created by a laboratory wave maker that is suddenly switc hed on. Such a test is shown to give a good measure of the capsizabili ty of a hull form, and the resulting transient capsize diagram is comp ared with earlier studies of premature transient capsize under stepped sinusoidal forcing. Some useful design observations are also made, ba sed on the sustainable wave slope of a vessel under tuned, worst-case, beam-sea excitation. Realistic wind loading can give a 30% reduction in the sustainable wave slope. emphasizing that the capsizability of a symmetric, unbiased, vessel is an unreliable guide to its safety at s ea.