A car-ferry catamaran of 80m class has a large demand in the global market of high-speed ships and SHI(Samsung Heavy Industries) has recently developed its own design. The seakeeping characteristics or ride quality is an important factor to consider necessarily in designing such vessels. A high-speed ship is inevitably accompanied by the excessive motion which causes passengers to experience extremely unpleasant discomfort, such as seasickness, nausea, and vomit. The present paper addresses an effort to improve the seakeeping property by developing the active ride control technology using control surfaces. An adequate mathematical model describing the motion of a vessel subjected to wave excitations is established and used to analyze the dynamic property of the catamaran. Heave and pitch motions are only considered in this paper. Then the effects of control suffices are investigated by comparing the controlled responses with the uncontrolled ones. The fins or fins demonstrate the capability of reducing the motion significantly.
The worldwide market of car-ferry is growing rapidly. Its tendency of demand is characterized by increasing the speed up to 50 knots and enlarging the size up to 100m. The high speed is achieved by designing a light-weight ship. Designing such a large-size high-speed vessel requires an accurate understanding of wave loads imposed on the vessel in waves. The operation of a high-speed catamaran in waves produces greater emphasis on the aspects of vessel motions and resultant structural loads. This is due to the larger encounter frequencies arising from the higher speed, with attendant increase in accelerations, as well as the need to reduce motion magnitudes relative to the free surface. A car-ferry catamaran of 80m class was recently developed by SHI in its own design.