160GT型沖合底曳き網漁船の追波操業時の復原性

摘要

沖合底曳き網漁業は大きく分けると，二そう曳き， 一そう曳き（トロール），一そう曳き（かけ回し）の3 つに分けられる。本研究では，北海道で主に行われて いるかけ回し漁業を対象とした。かけ回し換業は追い 波条件下で曳網・揚網作業が行われるため，船体動揺 と波周期の間に同調が生じる可能性が示唆されている（ しかしながらこれまで操業中の動揺データの解析例は ほとんどなく，換業中の復原力や船体動揺の変化は明 らかになっていない。本研究では実操業時の沖合底曳 網漁船の復原力推定を行うとともに動揺データについ て周波数解析を行い，操業中の復原性能を明らかにす ることを目的とする。%Danish seine trawl which is major offshore trawler in Hokkaido is regarded as having high risk of the resonance due to the characteristics of its operation method. However, as there are few study of ship motions in fishing operation, the actual condition is not clear. In this study, we perform estimating ship stability and the characteristics of ship motions by frequency analysis based on the data of ship motion. In the result, the ship stability decreased at short wave length and the resonance occurred between the natural period of rolling motion and the encountered period of wave in hauling where ship speed decreased in the following sea. It is considered that the resonance should be avoided by hauling in quartering sea to prevent excessive rolling.