Comparisons on the Mooring Line Force and Cage Motion Characteristics of Gravity and Sea Station Cages

摘要

This paper gives the comparisons on the force and movement characteristics of different cage models. Three models were selected including one Gravity Cage, one Sea Station Cage and one Quasi-Sea Station Cage. The Sea Station Cage model has equivalent enclosed volume with Gravity Cage model but is bigger in cage diameter and height. The Quasi-Sea Station Cage model is of the same diameter with the Sea Station Cage model but is 1.4 times in cage height. This increases its effective aquaculture volume up to 2.2 times that of the latter one. This model test was carried out under floating and submerged conditions. Pure current, pure wave and wave combined with current conditions were set during the test. The force data were measured by the transducers attached to the bottom of each mooring line. Cage movements were analyzed by tracing the diodes fixed on the floating system or the rigid ring. Results show that current-induced loads depend on the cage style greatly but turn out to be relatively weak under wave conditions. Submergence of cages decreases the loads and movement range, especially under wave conditions. Comparisons on mooring line forces and cage movements are also made between different cage models and some conclusions on the selection of cage style were drawn.