Marine and hydrokinetic energy harvesting heavily depends on the type of Power Takeoff (PTO) that converts water motion into electricity. However, existing ocean energy converters can convert only one of ocean wave, tidal stream or marine current energy, which fails to fully exploit the potential when both energy sources are available, such as in the west coast near Washington and Oregon States and east coast near Maine State. Furthermore, they have the relatively low efficiency because of slow marine current and reciprocating wave motion speeds. This invention is a hybrid energy converter that simultaneously harvest ocean waves, tidal streams, marine currents into electricity using a single device with high efficiency and low cost. The hybrid PTO is developed based on our award-winning mechanical motion rectifier (MMR) based power takeoff that converts the oscillating wave motions into unidirectional rotation and a synergic integration of motion transmission that allow marine and tidal turbine to simultaneously drive the same generator to produce electricity. The device compromises a floating surface body, a submerged second body, a hydro turbine parallel to the ocean current, a motion rectification mechanism for converting the oscillating ocean wave motion into a unidirectional motion, and a mechanism to couple the marine turbine rotation to drive the same generator to produce electricity
