Heave compensator A heave compensator (HC) is use minimize the motion of a suspended load, by paying out or taking in crane wire and thus compensating for the vertical crane motion. To a Body Point equipped with HC, it is possible to connect coupling elements of the following types: Fixed elongation coupling Simple wire coupling Multiple wire coupling Lift line coupling It is not possible to combine the active HC with a tensioner, and is not possible to de-couple a coupling point to which a HC is attached. The modeled active heave compensator is a cylinder type device, where oil is supplied in the pressure side of the piston, controlled based on measured vertical position of the crane top. A principal sketch is shown in Figure 4-19. In the present implementation a detailed model for internal function of the compensator is not included.