which must be overcome by the wave surge the pulling on the wave collector 120 by the directional force of a wave surge results in the transfer of force to all items that are attached to the wave collector 120 meaning the struts 124 following the movement of the wave collector 120 move upwardly along their respective slots 130 which in turn pull the pressure plate 121 upwardly as well the upward movement of the pressure plate 121 results in a decrease in volume of the bladder 110 which folds along its pleats 111 and the sea water contained in the expanded bladder 110 has nowhere to go but through outlet 128 when the surge has passed the flotation means 132 brings the hydroid 100 to a relatively upright position the one way valve 118 allows water to enter the bladder 110 the bladder 110 expands as it is refilled thereby lowering the pressure plate 121 which further assists in bringing the wave collector 120 to a position hovering over the top 116 of the housing 112 referring now to fig3 through 10 there is shown a second embodiment of the present invention designated the frond 200 illustrating one full cycle of the frond 200 beginning with full expansion as illustrated in fig3 and 4 and ending with full compression as illustrated in fig7 and 8 the frond 200 has a bulbous top 245.