An Effective Diagram for Ferrey Service Based on the Estmation of Oceanic and Tidal Current in the Middle of the Tsugaru Strait

Abstract

Navigation of the Seikan Renrakusen, other ferries and general vessels has been susceptible to the complicated oceanic and tidal currents which are caused by the Tsugaru Warm Current, a branch of Tsushima Warm Current, flowing in to the strait. Meanwhile, the estimated velocities by Ogura's method which has been so far used for the currents in this strait are very different from the observed one. So, a new method using C.A.S (Collision Avoidance System) were tried and got the good results for the estimation of currents at real time. With this results, the efficient diagram of navigation for ferrey service based on the adjustment of ship's velocity according to the current in main path are devised. Efficient use of this diagram enables us to accurately forecast the pass time at each point in the Tsugaru Strait between Aomori and Hakodate. A new method for the estimation of currents and a usage of the diagram are presented in this paper.