Effect of wind and current on course control of a maneuvering vessel

The equations of motion of a maneuvering vessel under the action of wind, current, rudder and propulsion are solved by the MATLAB Runge-Kutta solver ode45. The hydrodynamic derivatives used are those presented by Clarke et al. (1982)[1]. Wind and current loads are applied to segments of the vessel via a relative velocity formulation and drag coefficients. Course control is achieved by autopilot gains derived from a first order Nomoto approximation. The intent is to provide a tool for assessing a vessel´s maneuvering capabilities in terms of a simple single parameter (track deviation) under various environmental conditions. Results of simulations are presented for various wind and current scenarios.