Abstract: An offshore renewable energy system mounting platform is provided for positioning a renewable energy converter in a body of water. The platform includes a frame having a first structural member and a second structural member that are positioned adjacent one another at a mating connection and at least one mooring member affixed to the frame at a tethering location which is tethers the frame to a bed of the body of water. Either the first or second structural members comprises a buoyancy and a tension in the mooring member is arranged to counteract the buoyancy to urge the first and second structural members together at the mating connection. The platform may be manufactured as a set of pre-fabricated modular components which are subsequently assembled into the complete platform.

Abstract: A subsurface reaction body arranged for use in apparatus for converting wave motion in a body of water to useful energy is provided. The subsurface reaction body is arranged to be selectively filled with air to a maximum buoyancy configuration and to be filled with water to a minimum buoyancy configuration. The subsurface reaction body has an arrangement of chambers therein to inhibit free flow of water through the reaction body and to define at least one further preset buoyancy configuration between the respective maximum and minimum configuration.