Hydrodynamic aspects of the integrated ship movement control

Abstract

More and more ships are presently provided with propulsion systems consisting of two controllable pitch propellers and bow thrusters. Such systems are designed for improving manoeuvring characteristics of the ship in difficult passages, canals or areas of high traffic intensity. However their features are most effectively utilized if an integrated, computer- -aided control of the whole propulsion system by means of joystick is applied. The ship speed and movement direction, preset with the use of joystick, are not always exactly realized, especially if the ship is exposed to wind, wave and possible sea current effects. In such case the joystick software must include a hydrodynamic model of ship’s movement. The paper presents a model of the joystick-effected control and exemplary results of its computer simulation.