This paper presents a synthetic control algorithm that generates the rudder command angle to track the optimal route which is composed of straight-lines among way-points with keeping a required error limit. The control algorithm comprises three main lgorithms that is a course-keeping algorithm that eliminates the yaw angle difference between optimal route and current route a track-keeping algorithm that tracks the optimal route among way-points and a turning-control algorithm that includes the generation of optimal turning routes and control method. The effectiveness of the proposed control algorithm is assured through computer simulation.