Abstract: Blocks for constructing a breakwater substantially comprises a front wall, a rear wall disposed in parallel and spaced-apart relationship relative to the front wall, and at least one partition wall disposed perpendicular to the front and rear walls and integrally connecting the above two walls to form at least one vertical open-ended chamber between the front and rear walls, wherein the improvement is characterized in that at least one vertical open-ended hole is formed on each of the front and real walls of the block such that the vertical open-ended hole can be in alignment with corresponding vertical open-ended holes formed in the same manner on front and rear walls of the blocks in upper and lower rows when the blocks are arranged in rows and stacked vertically.

Abstract: In a breakwater which comprises a back wall, and at least one front wall pierced with holes to break up the impact of an incident wave, the improvements are proposed of providing a sloping back wall; of providing convex-concave indentations on the back wall; and of providing partitions to divide up the space between the back wall and the front wall or walls. Various embodiments include an embodiment with two front walls in which the holes in the rearmost front wall are smaller than the holes in the foremost front wall.

Abstract: A block of this invention for constructing a breakwater is characterized by having a front wall provided with a horizontal hole, an intermediate wall, a rear wall and a pair of spaced apart longitudinal walls which are disposed perpendicular to the above three walls for integrally connecting the three walls.Due to such construction, when the blocks are stacked up in rows to form a breakwater, the breakwater can have a first chamber which effects the dissipation of wave force and a second chamber which effects the firm integration of blocks along with the packing of a block uniting material therein.

Abstract: A breakwater which has a rear wall and several front walls to break up the incident waves, the front walls having holes therein to pass the waves, which holes diminish in size from the front wall which takes the initial impact of the wave towards the back wall. In various embodiments the breakwater may have a sloping back wall, convex-concave indentations on the back wall, partitions dividing up into compartments the chambers in front of the back wall, and a sloping second wall.