FISHERIES RESEARCH INSTITUTE,MOA,TAIWAN

The main purpose of this study was to realize the drag force on the anchor and the tension of the mooring lines against the Kuroshio current with its velocity of 2.8 knots. Based on the static analysis of the mooring lines on deployed fish aggregating devices (FADs) at the depth of 440 meters with velocity of 2.8 knots of the Kuroshio current, the drag force on the device is 2,250 lb. With the angle of the mooring line against the horizontal at 30o, the tension of the anchor and of the device were 2,600 lb and 4,470 lb, respectively. Therefore, the drag force of the polypropylene synthetic ropes was calculated as 5,571 lb (2.35 tons) which is much lower than the breaking strength 78.93 tons of the rope. The drifting of the device may be attributed to the broken-end of the polypropylene rope with a very smooth incision, which might have been cut by a sharp axe.
Key words: Deployed fish aggregating devices, Mooring lines, Mechanical analysis, Green Island