Dynamics of a ship steering in wind revisited

An integrated numerical environment for the exploration and assessment of nonlinear ship dynamics has been developed. The potential is demonstrated through an investigation of controllability of a modern Ro-Pax in steady wind. An improved wind-loading module is coupled to a standard maneuvering model, and the combination is put through "continuation analysis" in order to determine the branching behavior and specific bifurcations governing system responses. The analysis unveils a complex dynamical structure that dictates the limits of the ship's course-keeping capability. The topology, in state-parameter space of self-excited yawing in head wind, the occurrence of which had been established from earlier research, is now clarified. Interesting interactions between stationary and periodic responses are reported. The effectiveness of active control in removing undesirable responses is also part of the analysis.