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EP-4739614-A1 - HOISTING TOOL AND METHOD FOR UPENDING AN ELONGATE LOAD

EP4739614A1EP 4739614 A1EP4739614 A1EP 4739614A1EP-4739614-A1

Abstract

A hoisting tool for upending a monopile comprises a pull-in system and a pay-out system acting respectively on variable-length upper and lower links for connecting the tool to upper and lower sides of the centre of gravity of the monopile. The pull-in system and the pay-out system comprise respective drum portions on which the upper link and the lower link are wound respectively in mutually-opposed circumferential directions. The drum portions rotate together to pull in the upper link and to pay out the lower link simultaneously, counterbalancing torque applied to the drum portions by tension in the upper and lower links to reduce aggregate torque required to control rotation of the drum portions.

Inventors

  • BOSCH, Arnoud

Assignees

  • Seaway 7 Engineering B.V.

Dates

Publication Date
20260513
Application Date
20240704

Claims (20)

  1. 1. A hoisting tool for upending an elongate load, the tool comprising: a frame suspension point for suspending a frame of the tool from a crane; a pull-in system acting on a variable-length upper link for connecting the tool to an upper side of a centre of gravity of the load; and a pay-out system acting on a variable-length lower link for connecting the tool to a lower side of the centre of gravity of the load; wherein the pull-in system and the pay-out system comprise respective drum portions on which the upper link and the lower link are wound, the drum portions being arranged to rotate relative to the frame to pull in the upper link and to pay out the lower link simultaneously and being coupled together to offset torque applied to one of the drum portions by tension in the upper link against torque applied to another of the drum portions by tension in the lower link.
  2. 2. The tool of Claim 1 , wherein the upper link and the lower link are wound about the respective drum portions in mutually-opposed circumferential directions.
  3. 3. The tool of Claim 1 or Claim 2, wherein the drum portions are coupled to rotate together about a common axis.
  4. 4. The tool of Claim 3, wherein the drum portions are portions of a common drum, those drum portions being distributed along the common axis.
  5. 5. The tool of any preceding claim, wherein the upper link and/or the lower link comprise two or more limbs that are each wound on a respective one of the drum portions.
  6. 6. The tool of Claim 5, wherein the limbs are wound on respective drum portions that are in mirrored relation about a central plane.
  7. 7. The tool of any preceding claim, wherein at least one of the drum portions tapers along its axis of rotation.
  8. 8. The tool of Claim 7, wherein the at least one tapered drum portions is substantially frusto-conical.
  9. 9. The tool of Claim 7 or Claim 8, wherein the at least one tapered drum portion supports successive coils of the upper link or the lower link, those coils decreasing in diameter in a direction of taper or increasing in diameter against the direction of taper.
  10. 10. The tool of Claim 9, arranged such that while successive coils of the upper link of increasing diameter are being wound onto one of said drum portions, successive coils of the lower link of decreasing diameter are paid out simultaneously from another of said drum portions.
  11. 11. The tool of any of Claims 7 to 10, wherein two or more of the tapered drum portions share a common direction of taper.
  12. 12. The tool of any preceding claim, wherein the or each drum portion on which the upper link is wound has a greater average diameter than the or each drum portion on which the lower link is wound.
  13. 13. The tool of any preceding claim, further comprising a winch that is arranged to drive rotation of the drum portions.
  14. 14. The tool of Claim 13, wherein a drive belt driven by the winch is disposed between the drum portions.
  15. 15. The tool of any preceding claim, being arranged to pivot about the frame suspension point.
  16. 16. The tool of any preceding claim, wherein the frame comprises an upper frame member and a lower frame member that is movable relative to the upper frame member, the upper frame member extending from the frame suspension point to an upper link suspension point and the lower frame member supporting a lower link suspension point that is movable with the lower frame member relative to the upper frame member.
  17. 17. The tool of Claim 16, wherein the drum portions are mounted on the lower frame member.
  18. 18. The tool of Claim 16 or Claim 17, 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.
  19. 19. The tool of Claim 18, 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.
  20. 20. The tool of Claim 19, wherein the frame adjustment winch is mounted on the upper frame member.

Description

HOISTING TOOL AND 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. The winch dr