The water quality deterioration such as harbors might become a problem by demanding the public opinion of the environmental problem. There is a seawater exchange breakwater as one of the countermeasures. However, the seawater exchange function decreases in the point where the tidal condition. In this study, the seawater exchangable breakwater of the floating rubber body type was developed, and the characteristic was understood by the model experiment.
As a result, it was found that it was a structural type with an excellent performance.