A ribbed module is provided having a ribbed exterior surface defining a plurality of grooves and channels along the surface for receiving water and directing the water in a direction different from that in which it is received to reduce wave energy. The module is formed as a single integral unit, or as a pair of halves having complementary mating locking elements which when engaged join the halves to form the ribbed module. A buoyancy system is also included to adjust the buoyancy of the module for positioning of same at a select position in the water. A plurality of modules are connected to provide breakwaters which reduce the effects of wave action on the shore.