US Patent 10012037 Heave compensation method

A method of heave compensation between a floating installation, which has a drilling floor, and at least a riser or a pipe extending down towards, possibly through, a blowout preventer, the method including the steps of—installing an electromechanical actuator with attachment points, in the form of an end cap and an anchoring point, between the floating installation and a suspension device for the riser or the pipe; connecting the electromechanical actuator to a power supply and a control system; and heave-compensating for the relative displacement between the floating installation and the riser or the pipe by letting the control system adjust the length and power output of the electromechanical actuator.