Study on Judgment Criterion for Cancellation of Ferries Due to Ship Motion and Coastal Wave Data

In this study, from the viewpoint of ship safety and cargo management, examination of a criterion of judgment of ferry cancellation is carried out, based on both observed ship motion when encountering a typhoon and on coastal wave data at that time. Ship motion was observed using a 5,000GT-type ferryboat. As the wave data, coastal waves that were recorded with Nationwide Ocean Wave information network for Ports and HArbourS (NOWPHAS) instead of the encounter waves that are very difficult to measure are used. These data are analyzed by Spectral Analysis based on Auto Regressive (AR) modeling procedure, and the characteristics are analyzed in detail. Moreover, numerical reproductions of ship motion based on observed coastal waves are performed, and some future problems with respect to the decision on the criterion of judging of ferry cancellation are considered.