A heave compensating system for a marine vessel includes a hydraulic machine configured to be coupled to a load suspended from the vessel and to vary the distance between the load and the vessel in response to heaving motion of the vessel. The system further includes a second hydraulic machine in fluid communication with a hydraulic accumulator, both the first and second hydraulic machines are mechanically connected to one another and a shared electric motor, and a controller configured to control hydraulic movement of the first and second hydraulic machines and to control the supply of power to the electric motor.