A breakwater is an artificial structure constructed in the sea to protect ships from the effect of waves and storms.
Three types of breakwaters are common :
(a) Vertical sided.
(b) Rubble mound.
(c) Composite, with rubble mound as foundation and a vertical sided wall above it.
Figures 1 and 2 give the details.
Figure 1: Rubble Mound Breakwater
Figure 2: Composite Breakwaters