DYNAMIC INSTABILITY IN QUARTERING SEAS - THE BEHAVIOR OF A SHIP DURING BROACHING

The dynamic stability of ships encountering large regular waves from a stern is analyzed, with focus on delineating the specific conditions l eading to the uncontrolled turn identified as broaching. The problem's formulation takes into account motions of the actively steered or con trols-fixed vessel in surge-sway-yaw-roll with consideration of Froude -Krylov and diffraction wave excitation. Dynamical analysis of surf-ri ding is carried out for the general case of quartering waves, explorin g the route periodic motions-surf riding, loss of stationary stability , turn, capsize. Steady-state and transient analysis is carried out in the system's multidimensional state-space in order to identify all ex isting limit sets and locate attracting domains. Broaching from period ic motions is also a part of the investigation.