breakwater

breakwater offshore structure to protect a harbor from wave energy or deflect currents. When it also serves as a pier, it is called a quay; when covered by a roadway it is called a mole. In the United States a breakwater commonly consists of a long mound of stone rubble and of cheaper materials like rubber tires and oil drums. The flow of waves up its slope, and the formation of swirls by its rough surface dissipate wave energy. A pneumatic breakwater consists of perforated pipes discharging air bubbles; another type has underwater pipes that direct streams of water against approaching waves to cause them to break. Breakwaters are also used to promote sedimentation, which, depending on the breakwater's alignment, will infill to produce a stable beach. The Chesapeake breakwater was the first built in the United States. See coast protection .

break·wa·ter / ˈbrākˌwôtər; -ˌwätər/ • n. a barrier built out into a body of water to protect a coast or harbor from the force of waves.

breakwater.
1. An artificially placed construction in or around a harbour designed to break the force of the sea and to provide shelter for vessels lying within.

2. A low bulkhead across the forecastle deck of a ship which prevents seas which break over the bows or through the hawseholes from running aft. It diverts the water into the scuppers where it is drained overboard.