A wireline tensioner includes at least one sheave, a first accumulator unit, a second accumulator unit, a hydraulic distribution system, and a hydraulic cylinder unit which is operatively connected to the at least one sheave, to the first accumulator unit and to the second accumulator unit via the hydraulic distribution system. The first accumulator unit receives hydraulic fluid from the hydraulic distribution system at a first hydraulic pressure. The second accumulator unit receives the hydraulic fluid from the hydraulic distribution system at a second hydraulic pressure. The first hydraulic pressure is lower than the second hydraulic pressure.

A method of providing motion compensation of a subsea package with a synthetic rope comprising attaching the synthetic rope to the subsea package, supporting a first gripper with a wire rope from a winch capable of motion compensation control characteristics and gripping the synthetic rope with the first gripper, supporting a second gripper with a second wire rope, and repeating the following sequence: lowering the first gripper, the synthetic rope, and the subsea package a first distance, gripping the synthetic rope with the second gripper, releasing the first gripper from the synthetic rope, raising the first gripper the first distance, gripping the synthetic rope with the first gripper, releasing the second gripper from the synthetic rope, such that when the subsea package is lowered proximate the subsea landing location the winch capable of operating with motion compensation characteristics can operate to compensate for the vessel motion and smoothly lower the subsea package to the subsea landing location.

A method of providing motion compensation of a subsea package with a synthetic rope comprising attaching the synthetic rope to the subsea package, supporting a first gripper with a wire rope from a winch capable of motion compensation control characteristics and gripping the synthetic rope with the first gripper, supporting a second gripper with a second wire rope, and repeating the following sequence: lowering the first gripper, the synthetic rope, and the subsea package a first distance, gripping the synthetic rope with the second gripper, releasing the first gripper from the synthetic rope, raising the first gripper the first distance, gripping the synthetic rope with the first gripper, releasing the second gripper from the synthetic rope, such that when the subsea package is lowered proximate the subsea landing location the winch capable of operating with motion compensation characteristics can operate to compensate for the vessel motion and smoothly lower the subsea package to the subsea landing location.

The invention is a system for controlling the relative movement of a load P, comprising at least one main damper having a longitudinal action of stroke C and two ends with one end being connected to a frame and the other being connected to the load. A compensation device is included having at least one secondary damper of longitudinal action with two ends with one end being secured to the frame and the other end is connected to the end of the main damper connected to the load The secondary damper is arranged so that, at one point of stroke C, the secondary damper has an action orthogonal in direction to the direction of the movement.

The invention is a system for controlling the relative movement of a load P, comprising at least one main damper having a longitudinal action of stroke C and two ends with one end being connected to a frame and the other being connected to the load. A compensation device is included having at least one secondary damper of longitudinal action with two ends with one end being secured to the frame and the other end is connected to the end of the main damper connected to the load The secondary damper is arranged so that, at one point of stroke C, the secondary damper has an action orthogonal in direction to the direction of the movement.

A multi-cable subsea lifting system including two or more load-cable lifting apparatus (2a, 2b); a load cable (4a, 4b) extending from each load-cable lifting apparatus (2a, 2b) to a subsea attachment point; a torque measuring device (22) associated with each load cable (4a, 4b); one or more subsea anti-cabling devices (20), each anti-cabling device (20) including a motor (24) connected to a respective load cable (4a, 4b); and a controller (30) in communication with each motor (24) and torque measuring device (22); wherein the controller (30) is configured to actuate each motor (24) to impart a rotational force to its respective load cable (4a, 4b) in response to measurements obtained from the torque measuring device (22) with the aim to limit cabling, remove cabling or control heading either automatically or from external control.

A multi-cable subsea lifting system including two or more load-cable lifting apparatus (2a, 2b); a load cable (4a, 4b) extending from each load-cable lifting apparatus (2a, 2b) to a subsea attachment point; a torque measuring device (22) associated with each load cable (4a, 4b); one or more subsea anti-cabling devices (20), each anti-cabling device (20) including a motor (24) connected to a respective load cable (4a, 4b); and a controller (30) in communication with each motor (24) and torque measuring device (22); wherein the controller (30) is configured to actuate each motor (24) to impart a rotational force to its respective load cable (4a, 4b) in response to measurements obtained from the torque measuring device (22) with the aim to limit cabling, remove cabling or control heading either automatically or from external control.

A method and heave compensator for eliminating snap-load and heave effects at offshore deposition of a load into or onto the sea or seabed involves a heave compensator suspended between the load and the lifting device having a relatively stiff stroke response at small to moderate stroke lengths and then a softer stroke response at larger stroke lengths to avoid exceeding the dynamical amplification factor (DAF)-limitations of the crane/lifting device or on the load.

A method and heave compensator for eliminating snap-load and heave effects at offshore deposition of a load into or onto the sea or seabed involves a heave compensator suspended between the load and the lifting device having a relatively stiff stroke response at small to moderate stroke lengths and then a softer stroke response at larger stroke lengths to avoid exceeding the dynamical amplification factor (DAF)-limitations of the crane/lifting device or on the load.

The invention relates to a compensating device (200) for maintaining specifiable target positions of a load (206) which can be handled using a cable hoist (202) and which is attached to a cable (216) of the cable hoist, the respective specifiable target position of the load changing unintentionally to an actual position deviating from the target position. The compensating device consists of at least one sensor device (240, 242) for detecting the respective actual position of the load (206); a rotational drive (226, 228, 230) for specifying a cable length of the cable hoist (202); and at least one controller (244) which changes the cable length after the respective actual position has been detected until the load (206) re-assumes its target position. The respective drive (226, 228, 230) can be controlled at least partly by at least one hydraulic motor (226, 228, 230) with opposite rotational directions, said motor being connected to an actuating device (246) which has at least two separate pressure chambers (250, 252) with pressure levels that differ during operation, thereby forming a drive section (248) for the respective hydraulic motor (226, 228, 230), and which can be actuated by the controller (244).