風圧による船舶の横偏流について-III(日本航海学会第32回講演会)

Abstract

The investigation of a ship's drifting due to wind action is an important item from the view point of navigation, however it is very difficult to determine the extent of drifting due to wind force from the total drifting on the sea which reflects the influences of wind, wave, swell and current. The authors endeavored to measure the side-drifting due to wind action with parameter V (speed of ship) and W (wind velocity) when the ship's course took a right angle to the wind direction, and the experiments were carried out by the Hokusei maru and Oshoro maru, fishing training ships of Hokkaido University, and the results were reported. In this paper the authors attempted the application to the total ships founding on the basis of the former reports, and found the relation between the side-drifting and the ship's speed, wind velocity, the ratio between the longitudinal projected area (S) of the ship's above the water-line and the longitudinal projected area (S_W) of the ships below the water-line. The relation was expressed by the equation U(kt)=0.097√<S/S_W>e^<-0.140V>W(m/sec), and the calculated values from this equation were indicated in Table 2. The correction angle of the course was expressed by the equation Lee way=tan^<-1>0.097√<S/S_W>e^<-0.140V>W/V and the calculated values by the equation were indicated in Table 2.