Displacement Hull Forms

Displacement hull forms are the familiar monohull, the catamaran and the submarine. The moderate-to-full-displacement monohull form provides the best possible combinations of high-payload-carrying ability,economical powering characteristics, and good seakeeping qualities. Amore slender hull form achieves a significant reduction in wave-making resistance, hence increased speed:however, it is limited in its ability to beam. The catamaran provides a solution to the problem of low transverse stability. It is increasingly popular in sailing yachts and is under development for high-speed passenger ferries and research and small support ships. Sailing catamarans, with their superior ttransverse stability permitting large sail-plane area, gain a speed advantages over monohull craft of comparable size. A powered catamaran has the advantage of increased deck-space and relatively low roll angles over a monohull ship. The submarine, operating at depths which preclude the formation of surface waves, experiences significant reductions in resistance compared to a well-design surface ship of equal displacement.