MODEL EXPERIMENTS OF SHIP MOTION AND TURNING QUALITY OF A STERN TRAWLER WITH TOWING NET

Model tests were carried out of ship motions in regular waves and turning characteristics of a 124 tonne stern trawler under the conditions of trawling. The trawling condition was simulated by towing a body with the resistance equivalent to one estimated for the real net. The results showed that the ship motions such as pitch, heave and surge in head waves and following waves were little affected by trawling, but that the roll motion in beam waves was decreased because of the increase of the damping. It was also shown that the turning ability was remarkably reduced by trawling. The turning ability was improved by shifting the outside warp to the inside one, which corresponded to the common practice of loosing the outside warp to facilitate the turning of an actual ship under trawling.