Cruising Performance of Indonesian Ro-RO Ferries Under Action of Wind and Waves

The ro-ro ferries play an important role in Indonesian sea transportation. Therefore, performance of the Indonesian ro-ro ferries in operation become important in technical and economical point of view. This paper discusses effect of wind and wave to the ship speed, drift and rudder angle in order to maintain the ship direction. The wind velocities of 5 m/s, 10 m/s, 15 m/s, 20 m/s and 25 m/s with variation of direction from 0 degree (head wind) to 180 degrees (following wind) are used to investigated its effect on ship speed, drift angle and rudder angle. The wave is assumed to be fully developed due to wind. Therefore the wave parameters are determined using wind and wave correlation as defined in Beaufort scale. These environment parameters are used to numerically solve the maneuvering equation based on MMG model by using the Newton-Rhapson method.\ud Results of the numerical simulation show that the wind effect to the drift angle become significant in the wind and wave direction less than 80.0 degrees. In this range of wind and wave direction, effect of wave height is neglected small. The 0 effect of wave on the drift angle tends to be increase in range of wind and direction from 80.0 degrees up to 180.0 degrees. The necessary rudder angle is dominantly affected by the wind in the wind and wave direction of 40.0 degrees or larger. The wave effect becomes significant in the wind and wave direction is smaller that 100.0 degrees. The ship speed is significantly affected by the wind velocity compared with the effect of wave height. The effect of wave height to the ship speed occurs in the range of wind and wave direction from 20.0 degrees up to 100.0 degrees