Device for local reduction of wave amplitude

Means for effecting local reduction of sea wave amplitude comprising:

• a grid plate member adapted to be supported in the sea at a predetermined depth ensuring that said grid plate member remains submerged below the trough of the highest wave expected to be encountered in use of said wave reduction means, said grid plate member including a plurality of interconnected elongate supporting members;
• at least some of said supporting members hingedly supporting flapper valve plates which are operable between respective substantially open and substantially closed positions, each said flapper valve in its said open position permitting sea water to flow substantially unimpeded through the flapper valve and in its said closed position substantially blocking the flow of sea water through the flapper valve;
• means effective on each flapper valve to operate it to its open position in response to vertically downward movement of water as the wave amplitude decreases and to its closed position in response to vertically upward movement of the sea water as the wave amplitude increases;
• means for providing positive buoyancy to said grid plate member;
• anchoring means adapted to be supported on the sea bottom;
• and
• means connected between said anchoring means and said grid plate member for maintaining said grid plate member at said predetermined depth.