Performance of Cage Floating Breakwater

Abstract

Conventional floating breakwaters are examined and the feasibility of developing a cage floating breakwater is explored. Earlier studies on floating breakwaters reveal that, to achieve a transmission coefficient (\iK\i\dt) less than 0.5, the breakwater width to wave length ratio (\IW/L\N) should necessarily be greater than 0.4 for most of the configurations. Recent studies on cost-effective floating breakwaters indicate that by fixing a row of pipes below the floating body, the \IW/L\N requirement can be reduced to 0.15 without any compromise in the performance. This concept has been adopted in developing a new configuration to serve as: (1) a floating breakwater; and (2) as a possible shallow water cage culture unit. Experiments were conducted to study the performance of the cage floating breakwater under wave and wave-current environment. The results on transmission and reflection coefficients are presented and compared with those reported in the literature. The variation of water surface oscillations and velocities within the cage, the effect of mooring line stiffness, and initial tension on transmission characteristics are also discussed.