A wave energy converter comprising: a resonant heaving buoy point absorber comprising: a surface piercing float operably coupled to a water column tube extending downwardly from the surface piercing float, the tube being open at its bottom and being configured to accommodate a column of sea water therein, the tube being in communication with an air plenum provided within the surface piercing float to effect a trapping of a volume of air above a top surface of the column of sea water accommodated within the water column tube, the plenum being configured such that operably movement of the resonant heaving buoy point absorber expands and compresses the trapped volume of air; and a power take off, PTO, in communication with and responsive to air vented from the plenum resultant from a reaction of the heaving buoy point absorber against the top surface of the enclosed column of sea water; a plurality of adjustable inertial mass tubes, each adjustable inertial mass tube having a top and a bottom, the bottom being in open fluid communication with sea water, each tube being configured to accommodate a mass of sea water therein, the retention of the mass of sea water being controlled by a valve in fluid communication with the top of the tube such that sea water is retained in the tube during a movement of the point absorber in response to wave action thereon; a fixed mass ballast; wherein each of the surface piercing float, the water column tube, the plurality of adjustable inertial mass tubes and ballast are configured to rise and fall together as a unitary body in response to passing waves, and wherein the plurality of adjustable inertial mass tubes are arranged symmetrically about the column of sea water accommodated within the water column tube. a resonant heaving buoy point absorber comprising: a surface piercing float operably coupled to a water column tube extending downwardly from the surface piercing float, the tube being open at its bottom and being configured to accommodate a column of sea water therein, the tube being in communication with an air plenum provided within the surface piercing float to effect a trapping of a volume of air above a top surface of the column of sea water accommodated within the water column tube, the plenum being configured such that operably movement of the resonant heaving buoy point absorber expands and compresses the trapped volume of air; and a surface piercing float operably coupled to a water column tube extending downwardly from the surface piercing float, the tube being open at its bottom and being configured to accommodate a column of sea water therein, the tube being in communication with an air plenum provided within the surface piercing float to effect a trapping of a volume of air above a top surface of the column of sea water accommodated within the water column tube, the plenum being configured such that operably movement of the resonant heaving buoy point absorber expands and compresses the trapped volume of air; and a power take off, PTO, in communication with and responsive to air vented from the plenum resultant from a reaction of the heaving buoy point absorber against the top surface of the enclosed column of sea water; a plurality of adjustable inertial mass tubes, each adjustable inertial mass tube having a top and a bottom, the bottom being in open fluid communication with sea water, each tube being configured to accommodate a mass of sea water therein, the retention of the mass of sea water being controlled by a valve in fluid communication with the top of the tube such that sea water is retained in the tube during a movement of the point absorber in response to wave action thereon; a fixed mass ballast; wherein each of the surface piercing float, the water column tube, the plurality of adjustable inertial mass tubes and ballast are configured to rise and fall together as a unitary body in response to passing waves, and wherein the plurality of adjustable inertial mass tubes are arranged symmetrically about the column of sea water accommodated within the water column tube. a plurality of adjustable inertial mass tubes, each adjustable inertial mass tube having a top and a bottom, the bottom being in open fluid communication with sea water, each tube being configured to accommodate a mass of sea water therein, the retention of the mass of sea water being controlled by a valve in fluid communication with the top of the tube such that sea water is retained in the tube during a movement of the point absorber in response to wave action thereon; a fixed mass ballast; wherein each of the surface piercing float, the water column tube, the plurality of adjustable inertial mass tubes and ballast are configured to rise and fall together as a unitary body in response to passing waves, and wherein the plurality of adjustable inertial mass tubes are arranged symmetrically about the column of sea water accommodated within the water column tube.