J.S.Mani - Associate Professor, Ocwan Engineering Centre, Indian Institute of Technology Madras

The paper discusses on the possible use of partally submerged porous breakwater for sea defence .Both vertical and sloping types (with 40% porosity ) were investigated and found to be effective in controlling wave transmission. In case of vertical type, wave height reduction in the range of 50 to 90 % can be achieved for draft to water depth ratio of the order of 0.3. Further reduction in wave transmission by 20% is possible by adipting an additional row of porous breakwater (with a spacing of 0.75h, h:water depth)porous breakwater inclined at an angle of 35 to water level results in controlling wave the wave transmission remains unchanged compared to results obtained with a row of sloping breakwater.

Porous breakwater , coastal protection , wave attenuation , harbours , marinas