A ship is turned by steering. Then the ship is turned with constant angular velocity against the steering angle. However, the turning angular velocity is varied by blowing strong wind. A steering control system is designed to keep the constant turning angular velocity in the strong wind. First, the variation of the turning angular velocity is verified in regard of the strength and the direction of wind. Second, the ship's maneuverability is identified, which is expressed as Auto-Regressive eXogeneous (ARX) model, by each steering angle. Then the angular velocity of turning is controlled by applying Generalized Minimum Variance Control (GMVC) as one of predictive controls. Finally, the servo type GMVC is arranged with adjusting the wind's effect.