A study on the accuracy of the recent prediction technique of ship's manoeuvrability at early design stage

IMO's interim standard for ship manoeuvrability has accelerated the accurate prediction of ship's maneuverability. To evaluate the applicability of present prediction tool of ship's manoeuvrability at the early design stage, Kijima's prediction model, that is now widely used as a design tool, is adopted for a validation and sensitivity study. It is applied to three ships whose inherent manoeuvrability are different and to SR221 series model whose principal particulars are the same except stern name line. The result of the validation study shows a significant error especially for the prediction of course stability of an unstable ship such as full hull form. From the sensitivity study, it implies that the estimation error of linear hydrodynamic derivatives strongly affects the accuracy of simulation results, and this tendency becomes more apparent for the unstable ship. On the basis of these findings, the authors attempt to improve the prediction tool by making use of the recent research results. Then it is found that the revised method can predict the manoeuvrability more accurately even for an unstable ship.