Pages 141-148
In this study, an investigation on the dynamic instability of unstable rolling induced by pitching of a planing craft, at high advance speeds, is carried out. Using a database, of measured three-component hydrodynamic forces acting on a fixed model, the nonlinear pitch-excited rolling of the craft is simulated, using the fourth order Runge-Kutta method, varying inertia moment, roll damping, amplitude of pitching and the height of center of gravity. The results show that the period of rolling induced by pitching has no relation with the period of pitching and is almost constant and unstable rolling occurs when the period of pitching is a multiple of half the period of induced of induced rolling. The critical range of instability and the minimum roll damping to prevent unstable rolling increase with the increase of the inertia moment, the increase of the amplitude of pitch and the decrease of the height of center of gravity.
