Performance of a model fish cage with copper-alloy net in a circulating water channel and wave tank

This study was aimed at establishing the load on of a circular fish cage with a chain-linked copper-alloy net under the action of ocean currents and waves. The test cage that was used for this purpose was a 1/15 scaled-down model of a real fish cage presently installed in the coastal area of Korea. The deformation and mooring line load of the model cage were observed under different current speeds of 0, 20, 40, 60, and 80 cm/s in a circulating water channel. The mooring line load and its pattern were also examined with respect to the gap between the cage and the supporting buoy (0 (no buoy), 0.5, 1, 1.5, and 2 m, respectively) under the action of a 0.15-m-high wave in the wave tank. Although the volume of the cage hardly changed, the mooring line load exponentially increased with increasing current speed. The addition of the supporting buoy to the cage decreased the maximum load and changed the loading pattern, with the peak load apparently reduced to less than half. The tank test observations were reproduced by computer simulation.