Heave motion compensation system

A heave motion compensation system for use with an offshore hoisting device, the heave motion compensation system comprising:

• a heave compensation cylinder, said heave compensation cylinder having a piston, the heave compensation cylinder being configured to be connected to a gas buffer for providing an offshore hoisting device with passive heave compensation;
• a sheave head comprising one or more sheaves for engaging a hoisting wire of the offshore hoisting device, wherein the sheave head is supported by the piston for movement along a heave compensation trajectory;
• and
• a sheave head track extending parallel to the heave compensation trajectory,
• wherein the heave motion compensation system is provided with a heave compensation adjusting system, the heave compensation adjusting system comprising:
• an adjusting winch with an associated adjusting wire;
• a trolley, the trolley being coupled to the piston of the heave compensation cylinder via a connector device and being coupled to the adjusting winch via the adjusting wire;
• a trolley track, the trolley track extending parallel and adjacent to the heave compensation trajectory;
• one or more sheaves, located at an end of the adjusting track, for guiding the adjusting wire in a loop along the trolley track, wherein the adjusting winch is configured to pull the trolley, and thus the piston of the heave compensation cylinder, in opposite directions along the heave compensation trajectory;
• and
• a control device, the control device being adapted to control the speed of the adjusting winch.