Consideration on the Establishment of Roueh-Sea State

The sea trials for new ships are carried out for guaranteeing the ship performances in still water. Of course, this does not guarantee the performances in operating sea condition. But the ships mostly operate in winds, waves and currents and not in still water. Usually, those effects are included in the so called sea-margin.Following to the development of sea-keeping theory and motion/wave measurement technology, the increasing demand for guaranteeing the ship performances in operating condition is natural. In this context, the establishment of the “rough sea state” will be useful as one step for realizing the guarantee in operating condition.The “rough sea state” is one of the evaluation-sea-states. Evaluation-sea-states are used as key condition that the evaluations of ship performances are carried out comparing with the monitored actual results. In this paper, we proposed such a “rough sea state” based on added wave resistance and long-term wave database constructed by hind-cast technique.