長崎丸における単錨泊中の振れ回り運動からみた安全水域について

概要

論文の詳細を見る
Estimating Nagasaki Maru's whirling motion at single anchor is very important for the Captain and deck officers. In order to prevent accidents such as direct contact with other ships and obstacles on the sea floor, we continuously observed the whirling motion at a single anchor by using the DGPS. The results are as follow. 1) At a Beaufort's wind scale (wind force henceforth) of 2 and under, the wind directed against the anchor chain side and a slow whirling of the bow was observed. 2) At a wind force between 3 and 4, a regular elliptic motion was observed. 3) At a wind force 5, a distorted figure 8 movement forming unequal lobes was observed. 4) At a wind force 6, an amplified movement during wind force 5 was observed. 5) At a wind force 7, the relative heading angle formed in both the right and left sides with respect to the wind direction became equal, and a maximum whirling-breadth of 82 meters was measured. 6) When Nagasaki Maru is anchored on a single chain, the following equation for the average distance of transverse movement "d" and degree of whirling "a" with respect to wind speed "v" was determined. Moreover, the maximum distance of transverse movement was determined as approximately 1.5 times the value of "d". d=k1_v a=k_2v+5 d : the average distance of transverse movement (m) k_1 : 2.0 [1/knot] v : wind speed (knot) a : degree of whirling (°) k_2 : 1.0 [1/knot]
2004-10-16