NOVELTY - The apparatus (10) has movable reaction masses suspended beneath buoyant members e.g. floating buoy (12), by a set of linkages. Each linkage comprises an elongate non-rigid member which allows each buoyant member or each reaction mass to move relative to one another. Each linkage is associated with an extensible member that provides a restoring force for biasing the linkage to a non-extended configuration, such that the linkage is maintained in tension. Converters convert kinetic energy of relative movement between each buoyant member and each reaction mass into useful electrical power.    USE - Floating, self-reacting wave energy conversion apparatus for converting wave energy into useful electrical power.    ADVANTAGE - The apparatus captures power from both the vertical and horizontal energy components in the ocean's waves. The reaction masses are streamlined to minimize drag resistance of the dynamic motion of the reaction masses. The linkages provide stiffness between 100 and 100,000 kilo Newton/meter and of approximately 2,000 kilo Newton/meter, and provide a damping between zero and infinity, and of approximately 500-10,000 kilo Newton/meter. The apparatus allows a user to adjust the stiffness and/or the damping of linkage to tune the apparatus to suit the environment conditions e.g. varying weather/sea conditions, within which the apparatus is to be used. The apparatus allows a submerged reaction structure to be suspended below the floating buoy by non-rigid tethers, which comprise steel cables or any other suitable mooring material such as rope, thus eliminating the need for guides/bearing surfaces, thus significantly reducing size and costs of the apparatus. The linkages eliminate the need of bearings and guides or struts, thus avoiding significant bending stresses and fatigue design issues.    DETAILED DESCRIPTION - The reaction masses have a spherical, toroidal or elliptical shape. An INDEPENDENT CLAIM is also included for a method for converting wave energy into useful power by utilizing a wave energy conversion apparatus.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a wave energy conversion apparatus.    Wave energy conversion apparatus (10)    Ocean surface (11)    Floating buoy (12)    Sea bed (13)    Submerged reaction structure (14)    Mooring lines (25)