The Collision in the Kanmon Strait its relation to the meteorological conditions

Abstract

The recent abrupt increase in the sea accidents was due to the increasing marine traffic congestion for the purpose of supporting our rapidly developed economic activities. It is of urgent necessity to establish a countermove for the accidents, especially for the collision. The causality, of the accidents is complicated and differs case by case. Respective cases of accidents were examined in detail with much effort and time. But there lacks a consideration in broad aspects. And this report dealt, statistically, with the influence of the meteorological conditions on the frequencies of the collisions occurred in the Kanmon Strait during the period from 1962 to 1969. And the results obtained were summarized as follows: 1. The collision inclined to occur under the wind from SE or from NW, and that of weaker than 1.6m/s (especially, for the ships smaller than 3,000G.T. in the eastern half) or stronger than 10.8m/s (especially, in winter and spring, in the central area, for the ships smaller than 1,000G.T.) 2. More than 70% of the collisions occurred under the good visibility (better than 4km). When the different time length according to the visibility was taken into account, the poorer visibility than 4km inclined to induce the collisions (especially, in winter and spring, in the Hayatomo Seto, the western and the eastern areas, for the ships of the 100 to 1,000G.T. class). 3. The number of collisions per unit time under the poor visibility (poorer than 2km) was about 8 times as large as that under the good visibility (better than 2km). 4. The ships of the 100 to 1,000G.T. class were concerned with about 80% of the the collisions under the poor visibility; and about 55% of the collision under the poor visibility were those by the pair of the ships of this class. 5. The collision rate per ship passed (P_<PV>) under the poor visibility increased in accordance with the size of ship (x in gross tons) keeping the following relation: P_<PV>=0.10x^<0.79>×10^<-4> 6. The size of the ship had a clear relation to the influence of the visibility. Namely, the value of P_<PV> was 2.17x^<0.20> times as high as that under the good visibility.