THE CONTROLLABILITY OF A SMALL VESSEL OPERATING IN SEVERE FOLLOWING SEAS

A vessel operating in severe following seas often experiences steering difficulties, with the potential danger of broaching-to. Investigations of this phenomenon carried out in the past have tended to concentrate either on free running model experiments, or on numerical simulations carried out in the time domain using equations of motion often considerably simplified. Most broaching numerical models to date are constrained to three degrees of freedom: surge, sway and yaw. This paper describes a more detailed mathematical model which has been developed to include the effect of roll motion and the cross coupling with other motions. The paper also presents a series of simulation results.