SWATH - THE PAST, THE PRESENT AND THE FUTURE

This paper traces the development of the SWATH (small waterplane area twin hull) concept from early ideas through some of the vessels which are now in service. Attention is drawn to some of the principal features of SWATH vessel design and their effects on the performance of the vessel. In particular, the options available regarding the choice and location of propelling machinery together with the associated problems are considered and solutions which have been adopted or proposed are reviewed. The problems of comparing widely different types of marine vehicles are then discussed. A quantitative analysis of the relative performance of SWATH vessels and craft of other types (e.g. monohulls, catamarans, hydrofoils etc) is then quoted and analysed for a range of different sea states. Finally the paper reviews the other advantages and disadvantages of SWATH vessels compared to the alternatives and suggests the types of employment in which SWATH vessel features show to their maximum advantage.