No abstract

Among the recent problems in the fisheries in Japan, the development of fish farms is getting to be important. The breakwater for fish farms is required to have the functions of exchanging sea water and the preservation of fishing ground, as well as the outer facilities of finning ground.. Various types of breakwater to meet the requirements can be considered,the floating breakwater being one of them. When we limit the studies in the wave damping effect of a mobile breakwater, we can summarise that an effective floating breakwater should have sufficient draught under water surface and should have a comparatively large displaced water volume. In other words, the natural oscillation period of the floating body must be large enough as compared with that of the incident wave. (R. L.Wiegel '64) (K. Horikawa et al. '64) for practical purposes the studies on the shape and type must follow. However, if a floating breakwater is provided with a mechanism for attenuating wave, the above-mentioned criterion for the effectiveness must be largely changed.