Abstract
For the design of ships or offshore structures, the long term wave statistics is very important. Usually, ship data namely the visually observed data on board are used for such purpose. But, the density of ship data are not uniform over the sea area and there is another problem on the accuracy of visual observation.
Recently, a new wave statistics of North Pacific Ocean was published by I. WATANABE et al. (1992), and this statistics includes hind-casted long term wave data other than the conventional ship data and measured data by buoys.
There are differences between the characteristics of ship and hind-casted data, but the effects on long term ship responses are not clear.
So, this paper investigate the influences of the differences of wave statistics on long term ship motion and long term ship operability.
