Editing Breakwater (structure) (section)

==Purposes==
[[File:Quebra Mar by Diego Baravelli.jpg|thumb|Barra da Tijuca – Rio de Janeiro]]
Breakwaters reduce the intensity of wave action in inshore waters and thereby provide safe harbourage. Breakwaters may also be small structures designed to protect a gently sloping [[beach]] to reduce [[coastal erosion]]; they are placed {{convert|100-300|ft|-1||}} offshore in relatively shallow water.

An anchorage is only safe if [[ship]]s anchored there are protected from the force of powerful waves by some large structure which they can shelter behind. Natural [[harbour]]s are formed by such barriers as headlands or [[reef]]s. Artificial harbours can be created with the help of breakwaters. Mobile harbours, such as the [[D-Day]] [[Mulberry harbour]]s, were floated into position and acted as breakwaters. Some natural harbours, such as those in [[Plymouth Sound]], [[Portland Harbour]], and [[Cherbourg]], have been enhanced or extended by breakwaters made of rock.