A structure for converting wave energy that is positioned in seawater in the path of oncoming waves, comprising: a wave-engaging forward barge; an after barge; a central barge, each of the forward and after barge is being movably connected to the central barge 12 so as to allow for articulated motion there between; an inertial damper plate connected to a lower portion of the central barge and operatively connected to provide displacement stability to the central barge, the inertial damper being connected via spud elements to the central barge so as to produce a pendular motion of the center barge while floating in the seawater; an energy conversion device (21, 25) operatively connected to the wave-engaging forward barge, the after barge and the central barge so as to collect and convert energy from wave motion impacting and displacing the wave-engaging forward barge and the after barge relative to the central barge characterized by a mechanism (32, 34) for controllably submerging and re-floating the structure so as to movably reposition the structure between the surface of the seawater and under the surface of the seawater, wherein the mechanism (32, 34) for controllably submerging and re-floating the structure includes a weight attached to a bottom portion of the central barge, wherein each of the wave-engaging forward barge, the after barge and the central barge has gates (11a, 12a, 15a) on the top of the barges and gates (11b, 12b, 15b) on the bottom of the barges (11,12,15) configured to be controllably opened to allow seawater to flood open cavities of each of the barges (11,12,15) when submerging the structure, and that refloating elements using compressed air tanks or gas-generating explosive charges in each of the wave- engaging forward barge, the after barge and the central barge are configured to force out the seawater in the cavities of the barges (11,12,15) while the gates (11b, 12b, 15b) on the bottom of the barges (11,12,15) are controlled to be open and the gates (1Ia, 12a, 15a) on the top of the barges (11,12,15) are controlled to be closed when re-floating the structure. a wave-engaging forward barge; an after barge; a central barge, each of the forward and after barge is being movably connected to the central barge 12 so as to allow for articulated motion there between; an inertial damper plate connected to a lower portion of the central barge and operatively connected to provide displacement stability to the central barge, the inertial damper being connected via spud elements to the central barge so as to produce a pendular motion of the center barge while floating in the seawater; an energy conversion device (21, 25) operatively connected to the wave-engaging forward barge, the after barge and the central barge so as to collect and convert energy from wave motion impacting and displacing the wave-engaging forward barge and the after barge relative to the central barge characterized by a mechanism (32, 34) for controllably submerging and re-floating the structure so as to movably reposition the structure between the surface of the seawater and under the surface of the seawater, wherein the mechanism (32, 34) for controllably submerging and re-floating the structure includes a weight attached to a bottom portion of the central barge, wherein each of the wave-engaging forward barge, the after barge and the central barge has gates (11a, 12a, 15a) on the top of the barges and gates (11b, 12b, 15b) on the bottom of the barges (11,12,15) configured to be controllably opened to allow seawater to flood open cavities of each of the barges (11,12,15) when submerging the structure, and that refloating elements using compressed air tanks or gas-generating explosive charges in each of the wave- engaging forward barge, the after barge and the central barge are configured to force out the seawater in the cavities of the barges (11,12,15) while the gates (11b, 12b, 15b) on the bottom of the barges (11,12,15) are controlled to be open and the gates (1Ia, 12a, 15a) on the top of the barges (11,12,15) are controlled to be closed when re-floating the structure.