Twin-Rudder-System Configurations' Impact on Ferry Ships' Course-Keeping Ability under Windy Conditions.

Ship course-keeping plays a vital role in navigation safety, especially when a ship is operating under windy conditions. A method to control ship movements through rudder-system configuration is necessary to stabilize a ship's course. This paper describes the twin-rudder-system configuration design's impact on a ship's course-keeping ability under windy conditions. A timedomain simulation using the MATLAB-Simulink program was developed for this purpose. A proportional integral derivative (PID) controller was used to adjust the ship's heading angle according to the desired path. Several parameters--such as relative wind velocity and directions--were accounted for in the simulation. The result shows that, at a wind direction of 88o, the ship's course-keeping speed decreased; however, increasing wind velocity caused a large deviation in the ship's heading angle. Meanwhile, the ship's course-keeping speed increased with rising windspeed directions of 219o. The ship's course-keeping time, at around 219o under the simulation's wind direction, was 11.84% lower than during a previous sea-trial. A possible reason for this difference is that the simulation excluded waves and currents. [ABSTRACT FROM AUTHOR]