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

摘要

This paper gives the comparisons on the force and movementrncharacteristics of different cage models. Three models were selectedrnincluding one Gravity Cage, one Sea Station Cage and one Quasi-SearnStation Cage. The Sea Station Cage model has equivalent enclosedrnvolume with Gravity Cage model but is bigger in cage diameter andrnheight. The Quasi-Sea Station Cage model is of the same diameter withrnthe Sea Station Cage model but is 1.4 times in cage height. Thisrnincreases its effective aquaculture volume up to 2.2 times that of thernlatter one. This model test was carried out under floating andrnsubmerged conditions. Pure current, pure wave and wave combinedrnwith current conditions were set during the test. The force data werernmeasured by the transducers attached to the bottom of each mooringrnline. Cage movements were analyzed by tracing the diodes fixed on thernfloating system or the rigid ring. Results show that current-inducedrnloads depend on the cage style greatly but turn out to be relatively weakrnunder wave conditions. Submergence of cages decreases the loads andrnmovement range, especially under wave conditions. Comparisons onrnmooring line forces and cage movements are also made betweenrndifferent cage models and some conclusions on the selection of cagernstyle were drawn.