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The influence of tidal currents is a very important factor in port planning. The normal orientation of harbor facilities is usually designed to be parallel with the main direction of tidal currents to accommodate larger-sized vessels. However, there are still many ports that do not necessarily satisfy this fundamental rule, especially in small ferry berths. This study describes the present situation of Japanese ports under strong tidal currents. First, meteorological and oceanographic parameters have been observed to understand the properties of seawater and tidal currents. This observation revealed the existence of a complicated water density environment with strong tidal currents around OK Island in Japan. To evaluate a difficulty of ferry berthing, it is essential to take ship motion into consideration. This new numerical simulator makes it possible to reproduce motions of a berthing ship in tidal currents and winds while applying maneuvering forces. With this system, ship motions can be accurately reproduced, which makes it possible to quantify berthing criteria. The analytical methods presented here could be used for the planning of ports with strong tidal currents. [ABSTRACT FROM AUTHOR]

Mooring problems are still serious issues in port construction and operation. Although many studies have been carried out about moored ship motions or waves, effective countermeasures to reduce ship motions have not been accomplished in most harbours facing open seas. It is known that operators require detailed wave information near harbours when sea conditions become severe. In this study, a new numerical model is constructed for the prediction of the mooring limit condition due to typhoons. It is based on the theories of Kalman Filter, wave growth inside typhoons and wave decay in swells. The prediction model needs less input data than the meteorological models. The accuracy of the predicted model is verified for a port facing the Pacific Ocean when swells or wind waves propagate from typhoons in various situations. The prediction model is applied to other locations facing the Pacific Ocean. This new model allows us to predict the mooring limit condition 0.5–2 days before the influence of typhoons. Moreover, we propose a berth operation system to monitor the mooring limit condition using this prediction model in harbours facing open seas. [ABSTRACT FROM AUTHOR]