Experimental and numerical study of the vertical motions of a bulk carrier and a Ro–Ro ship in extreme waves

This paper investigates the experimental and numerical vertical motion responses of a bulk carrier and a Roll-on/Roll-off ship in extreme seas. The experimental data were obtained from seakeeping tests with scaled models in head waves at two Froude numbers. The wave traces were predefined, corresponding to wave records measured during storms in the North Sea. These wave records are particularly interesting because each of them include one abnormal wave. The ship models, which are similar in length but different in their geometry, were tested in the same predefined wave conditions to investigate the influence of the hull geometry on the extreme vertical ship responses. Conclusions are derived by comparing directly the measured responses from the two models. Experimental data are also used as benchmark to validate the predictions by a partially nonlinear time domain seakeeping numerical model. The numerical model code is then used to generalize the comparative analysis between the two ships. © 2015, Springer International Publishing AG.