Breakwaters

A double breakwater of the semisubmerged type comprising a base on the water bottom;

• a back wall of generally planar configuration inclined substantially uniformly over its entire length and inclining away from the incident wave direction, so that its upper part is farther from the incident wave direction than its lower part, and the upper part of said inclined back wall rises above the calm water level;
• its lower part being below the calm water level;
• a perforated barrier wall structure having a plurality of apertures or holes standing on the base, which has the same height as the inclined back wall;
• and a top wall support slab which projects horizontally from the top end of the inclined back wall and which is connected to the top of said perforated barrier wall structure, so as to form and completely cover a chamber between said base and said top, and said perforated barrier wall structure and said inclined back wall, and said chamber is adapted to partly retain at all times some of the water entering said chamber so as to aid in damping wave action;
• whereby said double breakwater exhibits substantially uniform blocking ability against a variety of waves having a broad range of wave length with the wave energy partly dissipated into vortices generated at said apertures or holes in said wall structure and also further partly converted into vortices generated when the water rushes against said inclined back wall.