Abstract
In this study, the occurrence of parametric rolling in head seas for high speed trimaran is experimentally investigated. First, in order to check the conditions where parametric rolling occurs, a towing tank test is carried out. A model of trimaran is a stabilized slender mono-hull type high-speed craft, and its distributions of displacement for main-hull and side-hulls are decided by based on a real high speed vehicle-passenger trimaran ferry. Next, in order to investigate dominant reasons of the variation of roll restoring moment as a cause of occurrence of parametric rolling, a captive model test with heave and pitch free conditions is carried out. In the test, the position of side-hulls is systematically changed. And the results indicate that the variation is mainly caused by side-hulls. Moreover, it was confirmed that the occurrence of parametric rolling estimated with the measured roll restoring moment and the calculated roll damping by the estimation method proposed in previous our study1), are consistent with the measured results.
