EP-4739613-A1 - A HOISTING ARRANGEMENT AND A METHOD FOR UPENDING AN ELONGATE LOAD

Abstract

A hoisting arrangement for upending an elongate load that has a centre of gravity positioned along its length, the arrangement comprising: a hoisting tool (18) having a reconfigurable frame (44) comprising an upper frame member (46) that is pivotably suspended about an upper pivot axis (54) and a lower frame member (48) that is movable relative to the upper frame member; a variable-length upper link (24) extending from the load on an upper side of the centre of gravity to a pull-in system (72) supported by the frame; and a lower link (26) extending from the load on a lower side of the centre of gravity to a lower link suspension point (40) that is movable with the lower frame member.

Inventors

• BOSCH, Arnoud

Assignees

• Seaway 7 Engineering B.V.

Dates

Publication Date

20260513

Application Date

20240704

Claims (20)

1. 1. A hoisting arrangement for upending an elongate load that has a centre of gravity positioned along its length, the arrangement comprising: a hoisting tool having a reconfigurable frame comprising an upper frame member that is pivotably suspended about an upper pivot axis and a lower frame member that is movable relative to the upper frame member; a variable-length upper link extending from the load on an upper side of the centre of gravity to a pull-in system supported by the frame; and a lower link extending from the load on a lower side of the centre of gravity to a lower link suspension point that is movable with the lower frame member.
2. 2. The arrangement of Claim 1, further comprising a variable-length mechanism that connects the upper and lower frame members and is operable to effect said movement of the lower frame member.
3. 3. The arrangement of Claim 2, wherein the variable-length mechanism comprises a frame adjustment winch mounted on the frame and acting on a wire of a reeving system that extends between the upper and lower frame members.
4. 4. The arrangement of Claim 3, wherein the frame adjustment winch is mounted on the upper frame member.
5. 5. The arrangement of any preceding claim, wherein the upper frame member is relatively upright and the lower frame member is relatively horizontal.
6. 6. The arrangement of any preceding claim, wherein a longitudinal axis of the lower frame member is movable from an acute angle to an obtuse angle relative to a longitudinal axis of the upper frame member.
7. 7. The arrangement of Claim 6, wherein the longitudinal axis of the upper member is pivotable about the upper pivot axis to adopt a substantially vertical orientation.
8. 8. The arrangement of any preceding claim, wherein the upper link extends to the pull- in system via an upper link suspension point that is spaced along the upper frame member from the upper pivot axis.
9. 9. The arrangement of any preceding claim, wherein the pull-in system is mounted on the lower frame member.
10. 10. The arrangement of any preceding claim, wherein the upper and lower frame members are pivotably connected to each other about a hinge axis.
11. 11. The arrangement of any preceding claim, wherein the upper link comprises an upper sling that extends from the load to a spreader and an upper wire that extends from the spreader to the pull-in system.
12. 12. The arrangement of Claim 11 , further comprising an auxiliary fixed-length coupling that acts between the spreader and the frame.
13. 13. The arrangement of any preceding claim, wherein the upper link is attached to the load at a position in alignment with a central longitudinal axis of the load.
14. 14. The arrangement of Claim 13, wherein the lower link is attached to the load at a position offset laterally from the central longitudinal axis of the load.
15. 15. The arrangement of Claim 13 or Claim 14, wherein the upper and lower links are attached to the load at respective ends of the load.
16. 16. The arrangement of any preceding claim, wherein the lower link comprises a lower sling that is connected to the load.
17. 17. The arrangement of Claim 16, wherein the lower link further comprises a bottom sling that is connected to the load and to the lower sling.
18. 18. The arrangement of Claim 17, wherein the bottom sling and the lower sling are connected to an intermediate saddle that cradles the load at a position between the centre of gravity and a bottom end of the load.
19. 19. The arrangement of any preceding claim, wherein the lower link is of fixed length.
20. 20. The arrangement of any of Claims 1 to 18, wherein the lower link is of variable length and comprises a lower wire that extends to a pay-out system supported by the frame.

Description

A HOISTING ARRANGEMENT AND A METHOD FOR UPENDING AN ELONGATE LOAD This invention relates to the challenges of upending a bulky elongate structure such as a monopile foundation or a jacket structure that is being lifted into a body of water by an installation vessel. A monopile is a hollow cylindrical column, installed in a vertical orientation, that is commonly used as a foundation for an offshore wind turbine. Typically, installation of a monopile involves transporting it horizontally to an installation site and then upending it by lifting one end using a floating crane. Once vertical, the monopile is driven down vertically into the seabed. Sometimes a monopile is transported aboard the vessel that supports the crane; alternatively, the monopile can be transported aboard a separate vessel or barge. A pivot axis for upending a monopile may be defined on a crane vessel as shown in EP 3517479, where the crane lifts the top end of the monopile while an upend frame on the main deck of the vessel controls the pivoting motion. However, if a monopile is longer than the height that is available between the crane hook and the water surface, transporting and installing the monopile by this conventional method may not be possible. Also, upending over the side of the vessel is restricted by the load capacity of its deck and hull. Consequently, this technique is not suitable for future extra-extra- large (XXL) monopiles that could, for example, weigh about 3000 metric tons. It is also possible to launch an elongate structure from a vessel, as shown for suction piles in WO 99/64684, but such a method does not allow for fine control of the position and verticality of the pile. A third installation method involves floating a monopile closed with plugs at its top and bottom ends, hence making the hollow monopile positively buoyant. Upending is done by suspending the top end of monopile from a crane hook and then ballasting the monopile through the bottom plug. This is an example of ballasting an elongate structure to upend it in water by creating differential buoyancy along its length, as also described for a jacket in US RE30823. However, controlling flooding of a structure with ballasting water can be complex and risks uncontrolled sinking. Also, for a monopile, it adds considerable time and expense to manufacture, install and remove the plugs. More generally, upending of a structure can be performed in air or in water, with the structure suspended between two cranes and/or winches or between two hooks of the same crane. In EP 2372143, for example, a cable arrangement for upending a pile employs two winches mounted on a self-elevating platform, also known as a ‘jack-up’. The pile swings below the deck of the jack-up, between the legs that support the deck. This renders the teaching of EP 2372143 unsuitable for use with a floating crane vessel, as the pile would clash with the hull of the vessel. CN 109879182 discloses a crane that supports a pair of winches. A cable of one of the winches is connected to a top end of a pile and a cable of the other winch is connected to a bottom end of the pile. With the crane suspending the pile from the winch cables, opposed movement of the winch cables is then synchronised to raise the top end of the pile while simultaneously lowering the bottom end of the pile. Similarly in CN 202745060, a crane handles the top of a pile while a separate winch handles the bottom of the pile. Employing a combination of winches and/or cranes in these ways adds risk to the operation because even a slight discrepancy in the control of the two winches and/or cranes could generate excessive tension in either of their cables. Various other upending solutions are known in the art, for example as taught in DE 88005030969, JP 2011079634, KR 20140004422, CN 107840254, CN 110803609, CN 11021 8098, CN 108726359, EP 2364949, WO 2015/014491 and WO 2018/052291. WO 2021/175871 discloses a crane that supports elongate rigging elements connected to a monopile at respective longitudinally-spaced connection axes. A pair of those elements, of fixed length, extend to a first connection axis and another of those elements, of variable length, extends to a second connection axis. A frame suspended from the crane supports a winch that pays out the variable-length element to lower the second connection axis relative to the first connection axis, which serves as a pivot axis about which the structure is upended. The monopile requires trunnions to which the fixed-length elements must be attached to define the first connection axis and from which the fixed-length elements must therefore eventually be detached. EP 3559442 discloses an apparatus for lifting and mounting a wind turbine blade on a wind turbine. US 2015/0228366 describes a tool for lifting and rotating a shipping container. The tool includes a rigging line that connects to the container at a lifting point and winch cabling that connects to the top of the container. T