워터젯 추진 활주선의 항주자세 변화에 따른 침로 및 횡동요 안정성 연구

Abstract

Calm water performance and stability of a water-jet propelled planing vessel are experimentally investigated in this paper. Trim tab dimensions for a full scale ship are determined through the analysis of towing tank model tests with a 1/6.5 scale bare hull model. In reservoir, speed tests are performed for a 3 ton class full scale ship with a water-jet. During tests, unstable roll and yaw motions are observed at high speed above 30knots, which are thought to be due to the decrease of stability as the running attitude changes with speed. Roll stability can be improved by the increase of the metacentric height(GM). The ship is equipped with trim tabs to adjust its running attitude. From the model test, it is found that trim tabs are effective to reduce trim and resistance at the speed lower than 20knots. In the full scale test, course-keeping stability gets worse when the wetted area of the forebody of the ship becomes larger due to excessive trim tab angles.5 scale bare hull model. In reservoir, speed tests are performed for a 3 ton class full scale ship with a water-jet. During tests, unstable roll and yaw motions are observed at high speed above 30knots, which are thought to be due to the decrease of stability as the running attitude changes with speed. Roll stability can be improved by the increase of the metacentric height(GM). The ship is equipped with trim tabs to adjust its running attitude. From the model test, it is found that trim tabs are effective to reduce trim and resistance at the speed lower than 20knots. In the full scale test, course-keeping stability gets worse when the wetted area of the forebody of the ship becomes larger due to excessive trim tab angles.