APPLICATION OF DOUBLE SKIN BREAKWATER WITH PERFORATION FOR REDUCING GREEN WATER LOADING ON HIGH SPEED CONTAINER VESSELS

This paper briefly reviews the phenomenon of green water faced by container ships and a time-domain method based on strip theory for predicting the occurrence of green water. Verification of this method with experimental data in regular waves is also carried out showing good agreement. A simple CFD hydrodynamic model is developed to represent the green water flow on deck and the parameters of this model are based on experimental data. In order to test the appropriateness of this model, comparison in terms of horizontal green water load (acting on a vertical structure) and vertical deck pressure is carried out with test data. Having achieved good agreement from this comparison, the research looks into the application of breakwaters in reducing the loading effects of green water. Double-skin breakwaters with and without perforation are simulated facing similar green water condition. Since protected structures can withstand a certain level of load without suffering detrimental effects, perforation is introduced to lessen the green water load that breakwater is to bear. Three systematically varied sizes of perforated holes are simulated and effects are evaluated. The research finally concludes on the performance of double-skin breakwater with/without perforation in reducing green water load and the overall effects of the perforation in balancing this load onto the structure and also the breakwater itself.