A device comprising a float (5) and a pivoting assembly of a rigid beam (10) and an elastic beam (30), firmly connected to each other, pivoting about a stationary point (15). The device transforms the rise and falls of the ocean waves into usable mechanical energy. In one embodiment, the elastic beam is latched into a latch mechanism (150). The latch mechanism obstructs the elastic beam to continue moving. The elastic beam deflects and accumulates potential power. When the elastic beam is released, it moves with a high speed and momentum. In another embodiment this momentum is utilized to counter-rotate an electric generator's two rotors (251, 252).A method of transforming the energy of a mass in reciprocating motion to electrical power.