Abstract
This paper discusses submerged breakwaters with cylindrical fish reefs. Various model tests were carried out to investigate regular and irregular wave transmissions. The tests revealed several fundamental principles about the wave transmission of the reef-type breakwaters. When the reef crest width is large, the wave dissipation can be expected to have a wide range of relative crest depths because of the function of the waves breaking on the crest. The transmission coefficient of the environmental submerged breakwater becomes slightly smaller than for the normal submerged breakwater.
