48. Design Requirements for Stability and Minimal Motions in a Storm

The hydrodynamics of a ship in a storm is not limited to the hull below the calm-water waterline. In a storm, the operating waterline varies between the bilge and the deck, causing unpredictable wave forces on the hull as well as the possibility of slamming on flat surfaces and the flared sections of the vessel. The present work describes the early stage of a design process for a hull form that accounts for the range of changing of the waterline in order to insure stability under severe heave. With this approach, it is possible to reduce the metacentric height, which minimizes roll resonance. The concept is part of a consistent ship design process; conventional naval architectural approaches will still be needed for successful solutions for reducing the pitching and yawing of the vessel and as a necessary condition for using active stabilizers and other seaworthiness improvements.