A hoisting system is for hoisting a vertically-suspended object. The hoisting system has a winch having a winch drum with a hoisting rope. A first part of the hoisting rope has a first diameter and a second part has a second diameter being larger than the first diameter. The first part is connected with a first end of the second part. The first part is an inner part on the winch drum when the winch drum is completely wound. The second part has a further end that is connectable to the object for hoisting the object. A ratio between the first diameter and the second diameter is such that the minimum breakable load of the first part differs less than a factor of four from the minimum breakable load of the second part, and preferably less than a factor of three. A corresponding method is disclosed.

Aspects of the disclosure include apparatus for and methods of facilitating transfer of objects using a crane. Disclosed apparatuses include a target tracking device mounted on or near a crane at a first location, and a target located near a landing location for the object. The target tracking device and the target facilitate real time determination of relative motion between the two locations. Methods of using the same are also disclosed.

Aspects of the disclosure include apparatus for and methods of facilitating transfer of objects using a crane. Disclosed apparatuses include a target tracking device mounted on or near a crane at a first location, and a target located near a landing location for the object. The target tracking device and the target facilitate real time determination of relative motion between the two locations. Methods of using the same are also disclosed.

A method of upgrading a knuckle-boom crane to a heave-compensating crane includes: removing a knuckle-boom from a main boom; mounting a main boom extension to the main boom for increasing the length of the main boom; and mounting a heave-compensating boom at a far end of the main boom extension such that the heave-compensating boom extends in a downward vertical direction (Z) in operational use of the heave-compensating crane. The heave-compensating boom is configured to be pivotable with respect to the main boom extension in both horizontal directions (X, Y). A heave-compensation system is provided to the knuckle-boom crane, wherein the heave-compensation system compensates for horizontal variations by controlling the orientation of the heave-compensating boom relative to the main boom extension, and compensates for vertical variations by means of a further vertical heave-compensation system, such as a winch-based heave-compensation system.

Described herein are systems, methods, and structures for transferring an object between a ship and an offshore structure, comprising a hoisting mechanism arranged on the offshore structure and adapted to attach to the object, at least one range sensing device adapted to provide data relating to a detected distance from a reference point on the offshore structure to the ship, where the system is adapted to receive the data from the at least one range sensing device and to move the hoisting cable in response to the detected distance, and a motion reference unit adapted to provide data relating to a detected motion of the ship independently of the at least one range sensing device, and wherein the system is adapted to move the hoisting cable in response to the detected motion of the ship.

Described herein are systems, methods, and structures for transferring an object between a ship and an offshore structure, comprising a hoisting mechanism arranged on the offshore structure and adapted to attach to the object, at least one range sensing device adapted to provide data relating to a detected distance from a reference point on the offshore structure to the ship, where the system is adapted to receive the data from the at least one range sensing device and to move the hoisting cable in response to the detected distance, and a motion reference unit adapted to provide data relating to a detected motion of the ship independently of the at least one range sensing device, and wherein the system is adapted to move the hoisting cable in response to the detected motion of the ship.

The present invention provides a capturing mechanism and method for the recovery of at least one vessel to at least one marine platform; the at least one vessel having at least one engagement device either permanently or at least partially reversibly connectable to the same; the capturing mechanism including: a. at least one tensioned capturing line connected to the at least one marine platform; and b, at least one line maneuvering mechanism configured to displace the at least one tensioned capturing line in at least one direction selected from a group of up, down, left, right, forward, backward, playable into the at least one marine plat form, playable out of the at least one marine platform, playable into and out of the water and any combination thereof.

The present invention provides a capturing mechanism and method for the recovery of at least one vessel to at least one marine platform; the at least one vessel having at least one engagement device either permanently or at least partially reversibly connectable to the same; the capturing mechanism including: a. at least one tensioned capturing line connected to the at least one marine platform; and b, at least one line maneuvering mechanism configured to displace the at least one tensioned capturing line in at least one direction selected from a group of up, down, left, right, forward, backward, playable into the at least one marine plat form, playable out of the at least one marine platform, playable into and out of the water and any combination thereof.

A system for the recovery of a surface marine craft by a carrier ship includes a lifting device with which the carrier ship is intended to be equipped and which includes a lifting unit of the davit type, equipped with a lifting cable including, at one end, a connection interface, a pole bearing a guide cable, an anchor connected to one end of the guide cable, the connection interface for the lifting cable being coupled removably to the anchor, and a hauling cable. The system also includes a receiving device with which the marine craft is intended to be equipped, the receiving device including a forward module.

A system for the recovery of a surface marine craft by a carrier ship includes a lifting device with which the carrier ship is intended to be equipped and which includes a lifting unit of the davit type, equipped with a lifting cable including, at one end, a connection interface, a pole bearing a guide cable, an anchor connected to one end of the guide cable, the connection interface for the lifting cable being coupled removably to the anchor, and a hauling cable. The system also includes a receiving device with which the marine craft is intended to be equipped, the receiving device including a forward module.