SEAKEEPING OPTIMISATION IN PRELIMINARY SHIP DESIGN

A method is described which allows quick and accurate (PC computer) calculations of ship motions and seakeeping characteristics at low cost in the preliminary design stage. For practical reasons of design evaluation, the (generally) large amount of calculation results are reduced to a one number Seakeeping Prediction Index (SPI). After describing the relevant programs, the approach is applied to the preliminary design of a modern beam trawler in which a comparison of alternative designs using SPI is made. Finally, a short sensitivity study is carried out to determine the effect that the longitudinal position of the fish processing unit has on the seakeeping characteristics of the most favourable of these beam trawler designs.