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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.

To ensure safe port operations around the world, it is important to solve mooring problems. In particular, the many ports that face open seas have difficulties with long-period waves. As a countermeasure, the installation of a breakwater is proposed for mooring safety. However, this often cannot be put into practice because of financial issues. Instead, port terminals control berthing schedules with weather forecasting. However, mooring problems remain unsolved, because of inaccurate wave forecasting. To quantify the current situation, numerical simulations are presented with ship motions, fender deflections, and rope tensions. In addition, novel simulations for mooring ropes are proposed considering tension, friction, bending fatigue, and temperature. With this novel simulation, the optimal mooring method in terms of safety and economic efficiency was confirmed. In terms of safety, the optimal mooring method is verified to minimize dangerous mooring situations. Moreover, the optimal mooring method shows economic benefits and efficiency. It can help to reinforce the safety of port terminals and improve the efficiency of port operations.