Air breakwaters are a portable, compliant, and feasible method of attenuating certain types of waves. The air breakwater concept (pneumatic) of attenuating waves by forcing compressed air through submerged, perforated pipe was patented in 1907 by Phillip Brasher. Subsequent prototype installation at Million Dollar Pier, Atlantic City (1908), and at El Segundo Pier, California (1915), proved successful. Air breakwaters are now used in harbors and on beach fronts throughout the world.
Current-producing breakwaters are generally divided into two categories: pneumatic and hydraulic. Pneumatic breakwaters consist of a simple perforated pipe through which compressed air is allowed to bubble through the water column to the surface. Two surface currents are generated by this process. One opposes the incident waves and is credited with their attenuation. The second, or leeward, current has no appreciable effect on the waves. Thus half of the possible attenuating capacity of pneumatic