Abstract: Extendable lattice type crane boom (2) for a crane (1), the boom comprising a lattice type base boom section (2a) and at least one lattice type telescopic boom section (2b), wherein the at least one telescopic boom section is adjustable with respect to the base boom section between a retracted position, in which the telescopic boom section is substantially inside of the base boom section, and an extended position, in which the telescopic boom section is at least partly outside of the base boom section, wherein a distal end of the base boom section to which a first guiding system (21) is mounted, the guiding system being configured to guide a movement of the telescopic boom section along the base boom section; wherein a proximal end of the telescopic boom section comprises a second guiding system (30) configured to guide a movement of the telescopic boom section along the base boom section.

Abstract: Telescopic lattice type crane boom for a crane, further comprising a locking system configured to lock at least one telescopic boom section with respect to a base boom section in at least an extended position, wherein said locking system includes a plurality of pins, each pin being configured to extend, in at least the extended position of the boom, at least partly through a corresponding pin receiving aperture provided in one of the base boom section and the at least one telescopic boom section.

Abstract: Method for moving a cantilever with respect to a deck of an offshore structure in longitudinal and rotational direction, around a predetermined virtual vertical axis, without providing a fixed vertical rotation shaft, comprising providing an offshore structure with a cantilever movable with respect to a deck of the offshore structure, providing cantilever rails on the bottom side of the cantilever and providing a supporting member or a skid shoe to support the cantilever on the deck, wherein the supporting member or the skid shoe has a top part configured for allowing the cantilever rail to have an angle deviating from the centerline of the skid shoe during rotation of the cantilever.

Abstract: Telescopic lattice type crane boom for a crane, further comprising a locking system configured to lock at least one telescopic boom section with respect to a base boom section in at least an extended position, wherein said locking system includes a plurality of pins, each pin being configured to extend, in at least the extended position of the boom, at least partly through a corresponding pin receiving aperture provided in one of the base boom section and the at least one telescopic boom section.

Abstract: Method for moving a cantilever with respect to a deck of an offshore structure in longitudinal and rotational direction, around a predetermined virtual vertical axis, without providing a fixed vertical rotation shaft, comprising providing an offshore structure with a cantilever movable with respect to a deck of the offshore structure, providing cantilever rails on the bottom side of the cantilever and providing a supporting member or a skid shoe to support the cantilever on the deck, wherein the supporting member or the skid shoe has a top part configured for allowing the cantilever rail to have an angle deviating from the centerline of the skid shoe during rotation of the cantilever.

Abstract: A vessel has a hull, a contact area at the hull near keel level for attaching to a structure, a lifting device and a lifting cable attached thereto and extending along a heave compensating member. The lifting cable extends along a substantially vertical lifting trajectory to a connect position below keel level. The heave compensating member includes a guide element for guiding the lifting cable and which is connected to a displacement device. The heave compensating member includes a compensator arm with a pivot end pivotally connected to a pivot point on the vessel at a predetermined transverse distance from the lifting trajectory, the cable guide element being attached to a free end of the compensator arm at or near the lifting trajectory, guiding the lifting cable in the direction of the pivot point, the arm being at or near the free end connected to the displacement device.

Abstract: A floating structure includes a hull and a work structure for supporting, lifting or lowering elongate objects. The work structure includes an elevating platform having an opening for receiving an object to be supported, lifted or lowered. The elevating platform is supported on the hull and is connected to a movable force element. The work structure includes a compensator platform pivotably supported on the hull around a pivot axis via a bracket or curved track. The compensator platform has an opening for receiving the object to be handled while the elevating platform is supported on the compensator platform via at least one elastomeric support. The force element is on one side attached to the hull and on the other side to the compensator platform for transmitting a driving force or a damping force to the platform when the platform is pivoted about a pin or displaced over the curved track.

Abstract: A vessel has a hull, a contact area at the hull near keel level for attaching to a structure, a lifting device and a lifting cable attached thereto and extending along a heave compensating member. The lifting cable extends along a substantially vertical lifting trajectory to a connect position below keel level. The heave compensating member includes a guide element for guiding the lifting cable and which is connected to a displacement device. The heave compensating member includes a compensator arm with a pivot end pivotally connected to a pivot point on the vessel at a predetermined transverse distance from the lifting trajectory, the cable guide element being attached to a free end of the compensator arm at or near the lifting trajectory, guiding the lifting cable in the direction of the pivot point, the arm being at or near the free end connected to the displacement device.

Abstract: The invention relates to a tie-back system for a crane comprising a rotatable base with a generally vertical support frame and a lifting arm which is with a lower end hingedly connected to the base in a hinge point, an upper part of the frame carrying a displacement member movable relative to the frame, the displacement member carrying a first cable guide means, a first cable extending from a first connection point on the arm along the first cable guide means to a first pulling device. The displacement member comprising a tie connection point for connection to a tie member, a second cable guide means attached to an upper part of the frame and a second cable extending from a second connection point on the arm along the second cable guide means to a second pulling device.

Abstract: The invention relates to a tie-back system for a crane comprising a rotatable base with a generally vertical support frame and a lifting arm which is with a lower end hingedly connected to the base in a hinge point, an upper part of the frame carrying a displacement member movable relative to the frame, the displacement member carrying a first cable guide means, a first cable extending from a first connection point on the arm along the first cable guide means to a first pulling device. The displacement member comprising a tie connection point for connection to a tie member, a second cable guide means attached to an upper part of the frame and a second cable extending from a second connection point on the arm along the second cable guide means to a second pulling device.

Abstract: A pipe lay vessel with a reel for carrying a length of pipe and first drive part for controlling rotation of the reel. A substantially vertical guide structure includes at its upper end a deflection member for deflecting the pipe from a first trajectory extending between the reel and the guide structure to a second, substantially vertical trajectory. A clamping member carries the vertical pipe section and has second drive for feeding the pipe along the vertical trajectory. A movable tension compensator (7) is provided at the first pipe trajectory for lengthening or shortening the first pipe trajectory to maintain a substantially constant tension of the pipe along the first trajectory during unwinding of the reel.

Abstract: A retractable thruster (5) is connected to a lifting device for retracting the thruster in two stages, the lifting device in the first stage lifting the thruster to a level at or near the keel (7) of the vessel, the second stage including lifting the thruster to an access level (13), located above the first level. The lifting device may be formed by a rack (3,3′) which can be constructed on deck level, or by hydraulic cylinders. Preferably the frame (6) which carries the thruster is formed by a closed container having buoyancy, the drive motor, gearbox and rotational drive unit being placed in the container.