Upending elongate structures offshore

Abstract

An upending system for upending an elongate element (14) from aboard a vessel offshore comprises an upending frame (26) that is pivotable with the element into an upright orientation about a horizontal pivot axis (28). The upending frame is arranged to support an upper portion of the element extending between the pivot axis and a top end of the element. A lifting tool (46) is engageable with the top end of the element and the upending frame extends to and is engageable with the lifting tool. A support frame (24, 36) is pivotably connected at a first end to the upending frame, and has a second end that is movable horizontally relative to a deck of the vessel.

Description

[0001] Upending elongate structures offshore

[0002] This invention relates to the challenges of upending an elongate structure from an installation vessel at sea. Those challenges are particularly acute when upending a bulky monopile, which will be used herein to exemplify the invention. The invention also addresses similar challenges that are encountered when upending other elongate structures or elements installed offshore, such as jacket foundations or wind turbine masts.

[0003] Monopiles are widely used as foundations for marine structures such as bottom-fixed offshore wind turbines. A monopile comprises an upright tube, conventionally fabricated from steel, that is landed on the seabed and then driven into the seabed soil to a required depth of embedment. A top portion of the monopile can remain above the surface if it is required as a base for constructing an above-surface structure upon the foundation, such as the mast of a wind turbine.

[0004] As there is a trend for larger wind turbines to be installed in deeper waters, the average size of monopiles is, correspondingly, increasing. For example, monopiles could be more than 100m long, up to 10m wide and weigh more than 2000 tons. For ease of manufacture and for stability at sea, such large monopiles are typically fabricated and transported in a horizontal orientation. This requires the monopiles to be upended into a vertical orientation at an offshore installation site. The inherent difficulties of manipulating such bulky loads offshore are compounded by the limited deck space that is available on an installation vessel, especially if the vessel was originally designed to handle smaller monopiles. Various upending tools or systems have therefore been proposed or developed to address these problems.

[0005] Typical upending systems comprise a pivoting upending frame that supports the monopile being installed, in combination with a crane to lift a top end of the monopile. The crane thereby effects pivoting of the monopile supported on the upending frame into an upright orientation as a bottom end of the monopile is overboarded over a side of the vessel and into the sea. Once the monopile reaches a vertical orientation over the sea, the crane lifts the monopile clear of the upending frame and then lowers the bottom end of the monopile onto the seabed to be driven further into the seabed soil. Upending systems are often used in conjunction with a pile gripper that guides the monopile to keep it vertical until it is embedded fully into the seabed soil. In an overly complicated solution, WO 2019 / 149674 proposes an upending frame that supports the bottom of a monopile and is combined with a gripper. WO 2016 / 105193 and EP 3083391 propose simpler solutions involving a pivoting cradle that engages the bottom end of the pile. However, the cradle could clash with a gripper or make the use of a gripper impossible; also, these systems would encounter operational limits if used for larger monopiles. Similarly, the use of a pivoting gripper ring to serve as an upending tool, as proposed in WO 2019 / 231329, also faces operational limits for larger monopiles.

[0006] In WO 2021 / 058544 and WO 2022 / 079112, two gripper rings like the single gripper ring of WO 2019 / 231329 are combined in a pivoting upending and gripping assembly. The gripper rings engage the tubular side wall of the monopile on respective sides of the pivot axis or the centre of rotation of the monopile.

[0007] WO 2018 / 146163 discloses upending frames for jackets and monopiles and employs two pivot axes. In JP H0412541 , a guiding trolley adjusts its angle during upending of an elongate element by a crane.

[0008] WO 2020 / 020817 and WO 2022 / 096523 disclose structures that guide and support a lifting tool to be fixed at the top of the monopile to interface with a hook of a crane. However, they do not disclose anything more than conventional upending frames to support and guide the monopile during upending by the crane.

[0009] US 8251004 describes a device for transporting structures on water, and for dismounting or installation of said structures. The device includes a tilting frame that is hingedly connected at a pivoting point to a water vessel such as a barge.

[0010] Against this background, the invention resides in an upending system for upending an elongate element from aboard a vessel operating offshore. The system comprises an upending frame that is pivotable with the element into an upright orientation about a substantially horizontal pivot axis. The upending frame is arranged to support at least part of an upper portion of the element that extends between the pivot axis and a top end of the element.

[0011] A lower end of the upending frame may be aligned with the pivot axis. A centre of gravity of the element may be disposed between the pivot axis and the top end of the element. In one arrangement, the system further comprises a lifting tool that is engageable with the top end of the element. In that case, the upending frame can extend to and be engaged with the lifting tool to locate the element relative to the frame. For example, the upending frame may have socket formations at its upper end that are arranged to receive trunnions protruding from the lifting tool. Conveniently, the lifting tool can disengage from the upending frame automatically in consequence of the upending frame reaching the upright orientation.

[0012] In another arrangement, the system further comprises a support frame that is pivotably connected at a first end to the upending frame and has a second end that is movable horizontally relative to a deck of the vessel. The second end may also be pivotable relative to that deck of the vessel, can be driven to move horizontally relative to the deck and conversely can be lockable against such relative movements.

[0013] The pivot axis may be at a level above the deck of the vessel and may be disposed outboard of the deck. When the upending frame is in the upright orientation, there can be a vertical clearance between the lower end of the upending frame and a level of the deck.

[0014] The inventive concept embraces an installation vessel that is equipped with an upending system of the invention. The vessel can further comprise a gripper. The gripper may be aligned with the upending frame to receive a lower portion of the element directly upon upending the element. The gripper may instead be on a side of the vessel opposed to an overboarding side over which the upending frame overboards the upended element.

[0015] The inventive concept also extends to a corresponding method of upending an elongate element, such as a monopile, a jacket foundation or a wind turbine mast, aboard a vessel operating offshore. The method comprises pivoting an upending frame with the element into an upright orientation about a substantially horizontal pivot axis, while using the upending frame to support at least part of an upper portion of the element that extends between the pivot axis and a top end of the element.

[0016] A lifting tool can be engaged with the top end of the element and with the upending frame before using the lifting tool to lift the top end of the element when initiating upending of the element. The method may then comprise disengaging the lifting tool from the upending frame automatically in consequence of the upending frame reaching the upright orientation. The upending frame can be supported with a support frame while pivoting the support frame relative to the upending frame, moving the support frame horizontally relative to a deck of the vessel, and / or pivoting the support frame relative to that deck of the vessel. Those movements of the support frame relative to the deck of the vessel can be driven or locked to block or prevent movement of the support frame.

[0017] The upended element can be overboarded directly by the upending frame into a gripper supported by the vessel or can be overboarded by the upending frame and then conveyed horizontally into a gripper supported elsewhere on the vessel.

[0018] Methods of the invention can include the preliminary step of transporting the element across water when aboard the vessel, with the lifting tool engaged with the top end of the element and also engaged with the upending frame.

[0019] The invention recognises that supporting an upper portion of an elongate structure during upending can improve stability and allow safer operation, in addition to mitigating the problem of clashing with a gripper. Thus, the invention provides an alternative to conventional monopile upending frames that support a monopile at the bottom.

[0020] In an upending frame of the invention, a monopile lifting tool is attached at the top of the monopile and suspended in the frame by trunnions or other stopper formations to transfer the load from the monopile to the hinge or pivot point of the frame during upending. This makes it possible to upend monopiles into a fixed gripper with little interference between the upending frame and the gripper and without the need to hinge or skid the gripper. Moreover, the upending frame is largely inboard of the vessel, over the working deck, which allows better opportunities to moor the vessel alongside a quay than with a conventional upending frame that typically protrudes laterally from the hull by 30m to 50m. This applies especially when upending is performed on one side of the vessel and the gripper is on the other side of the vessel to optimise crane capacity.

[0021] The invention provides a robust upending method with the hinge or pivot axis at or close to the monopile centre line, avoiding toppling and the need for back-tension wires or winches.

[0022] The upending frame of the invention can be used in two configurations: upending directly into the gripper; or upending in the frame and then slewing the upended monopile away from the frame and into an adjacent gripper. Direct upending into the gripper maximises crane capacity and minimises the interface between the gripper and the upending frame, allowing use of an existing gripper and leaving space for other equipment such as a noise mitigation system beneath the gripper. When used as a stand-alone upender, the upending frame is mainly inboard with no large cantilevered upending structure. This enables the vessel to enter ports and to moor at a quayside.

[0023] Embodiments of the invention provide an upending frame for upending an elongate element, such as a foundation, a monopile or a wind turbine mast, from a vessel. The frame comprises: a cradle to engage an upper section of the elongate element at least partially; a support, connected to the cradle at a hinge point, wherein the hinge point is located in the vicinity of the centre of gravity of the elongate element; and a sliding support frame pivotably connected to the cradle at a first end, and having a second end that is able to move horizontally on a deck of the vessel.

[0024] The cradle can engage the top half of the element. The hinge point may, for example, be at the bottom end of the cradle when the cradle is vertical.

[0025] An upper section of the cradle can be coupled temporarily to a lifting tool that provides an interface between the crane and the top of the element.

[0026] The second end of the sliding support frame can be constrained to move only along one direction or axis. The sliding support frame may comprise a displacement mechanism to move the second end and to guide rotation of the upending frame between horizontal and vertical configurations or orientations.

[0027] Embodiments of the invention also provide an upending system comprising a crane, a monopile lifting tool to connect a hook of the crane with the monopile, an upending frame, and a pile gripper to limit horizontal movement of the monopile when it is in a vertical orientation. The hinge point may be aligned with the centre of the upending frame. The lifting tool may be coupled to the upending frame.

[0028] Embodiments of the invention also provide an upending system for upending an elongate element from aboard a vessel operating offshore, the system comprising an elongate upending frame that is pivotable with the element into an upright orientation about a substantially horizontal pivot axis, wherein the upending frame is arranged to support at least part of an upper portion of the element that extends between the pivot axis and a top end of the element and is offset longitudinally toward the top end of the element, such that at least a majority of a length of the upending frame is disposed between the pivot axis and the top end of the element.

[0029] Embodiments of the invention also implement a method to upend a pile, the method comprising: supporting an upper section of the pile in the cradle of an upending frame; connecting a top end of the pile to a lifting tool for a crane; connecting the lifting tool to the upending frame; and lifting the top end of the pile.

[0030] The method may also comprise: when the pile is vertical, disconnecting the upending frame from the lifting tool; and rotating the upending frame from a vertical orientation to a horizontal orientation by moving a sliding support frame on a deck of the vessel.

[0031] In summary, an upending system for upending an elongate element from aboard an offshore installation vessel comprises an upending frame that is pivotable with the element into an upright orientation about a horizontal pivot axis. The upending frame is arranged to support an upper portion of the element extending between the pivot axis and a top end of the element. The upending frame may be offset longitudinally toward the top end of the element such that substantially all, or at least a majority of, the length of the upending frame is disposed between the pivot axis and the top end of the element.

[0032] A lifting tool can be engaged with the top end of the element and the upending frame can extend to and be engaged with the lifting tool. A support frame can be pivotably connected at a first end to the upending frame, and can have a second end that is movable horizontally relative to a deck of the vessel.

[0033] In order that the invention may be more readily understood, reference will now be made, by way of example, to the accompanying drawings in which:

[0034] Figures 1a and 1b are end views of a crane vessel of the invention when upending a monopile;

[0035] Figures 2a and 2b are top plan views corresponding to Figures 1a and 1b respectively;

[0036] Figure 3 is a top plan view of another crane vessel of the invention; and Figures 4a to 4d are end views of the vessel of Figure 3 when upending and gripping a monopile.

[0037] In a first embodiment of the invention shown in Figures 1a to 2b of the drawings, a crane vessel 10 is shown here using its aft-mounted main crane 12 to install a monopile foundation for a bottom-fixed offshore wind turbine. In this example, the vessel 10 carries three monopiles 14 that are upended and overboarded one-by-one in successive installation operations. Figures 1a and 2a show one of the monopiles 14 in a substantially horizontal orientation, before upending, whereas Figures 1b and 2b show that monopile 14 in a substantially vertical orientation, after upending. As can be seen in Figures 2a and 2b, the other two monopiles 14A lie horizontally on a working deck 16 of the vessel 10 to be installed subsequently during the same installation campaign.

[0038] In the context of the monopile 14 and related features, references in this specification to directional or positional terms, such as top, bottom, upper and lower, relate to the monopile 14 when in an upright orientation. However, those terms are also apt to describe the monopile 14 when it is oriented horizontally.

[0039] As is conventional, each monopile 14 is typically a steel tube that may narrow toward its top end 18 as shown in this example. The top end 18 protrudes above the surface 20 when the monopile 14 has been upended and driven into the seabed, ready for the mast of a wind turbine to be erected or assembled on top. By way of example, each monopile 14 may be about 100m long and up to 10m in diameter at its wider bottom end 22, and could weigh about 2500 tons. Such massive monopiles 14 reflect the increasing average size of offshore wind turbines. In this respect, an advantage of the invention is its suitability for upgrading existing installation vessels 10 that have been used previously to install significantly smaller wind turbines.

[0040] The monopile 14 shown here in the process of installation is held in an upending system that is mounted on the working deck 16 of the vessel 10 beside the base of the crane 12. The upending system comprises a support structure 24 that is fixed to the working deck 16 and an upending frame 26 that surmounts the support structure 24 and cradles the monopile 14. Initially, the upending frame 26 is oriented substantially horizontally but it is pivotably mounted to the support structure 24 to tilt around a substantially horizontal primary pivot axis 28 into a substantially vertical orientation. The upending frame 26 thereby supports and guides upending and overboarding movement of the monopile 14. When the monopile 14 has been overboarded and installed, the crane 12 can lift the next monopile 14A from the working deck 16 into the then-vacant upending frame 26, after the upending frame 26 has been returned to the horizontal.

[0041] In the context of the upending frame 26 and related features, references in this specification to directional or positional terms, such as upper and lower, relate to the upending frame 26 when in a horizontal orientation. However, those terms are also apt to describe the upending frame 26 when it is in an upright orientation.

[0042] Initially, the upending frame 26 supports the monopile 14 in a substantially horizontal orientation raised above the working deck 16. For this purpose, the upending frame 26 comprises an upwardly-concave cradle 30 of complementary part-tubular shape extending along and under an upper portion of the monopile 14, inboard of the pivot axis 28. The centre of gravity 32 of the horizontal monopile 14 also lies inboard of the pivot axis 28. In this example, the cradle 30 extends from the top end 18 of the monopile 14 to the pivot axis 28 although the cradle 30 could instead terminate short of or beyond the top end 18 of the monopile 14 at one end or inboard or outboard of the pivot axis 28 at its other end. However, it is advantageous for the lower end of the cradle 30 not to terminate too far outboard of the pivot axis 28 so that there is ample vertical clearance between the upright cradle 30 and the level of the working deck 16.

[0043] The cradle 30 is curved about a longitudinal axis of curvature that is parallel to, or coincident with, a central longitudinal axis 34 of the monopile 14. Mutually parallel longitudinal side edges of the cradle 30 lie in a plane that, in this example, also contains the central longitudinal axis 34 of the monopile 14. The cradle 30 is suitably of lattice construction, as exemplified here, for lightness and strength.

[0044] The support structure 24 of the upending system further comprises inclined arms 36 that together straddle, and form part of a lateral support frame for, the upending frame 26. The arms 36 are pivotably mounted at their upper ends to a bottom side of the upending frame 26. There, the arms 36 join the upending frame 26 on a common secondary axis 38 that is parallel to and inboard of the primary pivot axis 28 but is also inboard of the centre of gravity 32 of the horizontal monopile 14. The position of the centre of gravity 32 close to or at the hinge point centre line of the primary pivot axis 28 mitigates the risk of the monopile 14 toppling, with no need for wires or winches to apply back-tension to the monopile 14, yet also minimises the lifting force that is necessary to initiate upending.

[0045] The arms 36 extend down toward the working deck 16 at their bottom ends, where they are supported for pivotal movement relative to the working deck 16 about a common tertiary axis 40. The bottom ends of the arms 36 are also supported for translational movement from side to side across the vessel 10, in directions parallel to a plane containing the central longitudinal axis 34 of the monopile 14. For example, as will be described with reference to the second embodiment shown in Figures 3 and 4a to 4d, the bottom ends of the arms 36 could be pivotably attached to carriages that can slide, roll or otherwise translate across the working deck 16, for example on transverse rails.

[0046] Before installation, all of the monopiles 14 on the vessel 10 lie in crosswise orientation extending across and beyond the working deck 16. The top and bottom ends 18, 22 of the monopiles 14A lying on the working deck 16 overhang respective sides of the vessel 10. Conversely, the monopile 14 in the upending frame 26 has its top end 18 slightly inboard of one side of the vessel 10 and its bottom end 22, correspondingly, further outboard from the other side of the vessel 10. The monopile 14 is overboarded and installed on that latter side, which will therefore be referred to herein as the overboarding side 42 of the vessel 10. In this embodiment, the overboarding side 42 may also be regarded as an installation side of the vessel 10.

[0047] The horizontal pivot axis 28 between the upending frame 26 and the support structure 24 is disposed above and outboard of the overboarding side 42 of the vessel 10. Thus, the support structure 24 comprises braces 44 that converge from the working deck 16 to the pivot axis 28 in upward and outboard directions. In this example, the central longitudinal axis 34 of the monopile 14 intersects the pivot axis 28. Also, in this example, the pivot axis 28 is substantially parallel to the overboarding side 42 of the vessel 10.

[0048] When the monopile 14 is horizontal, its centre of gravity 32 disposed on its central longitudinal axis 34 is inboard of the pivot axis 28 as noted above. Consequently, the monopile 14 and the upending frame 26 are stable in their mutually horizontal orientation. Nevertheless, additional fixings can tie the monopile 14 to the upending frame 26 and tie the upending frame 26 to the support structure 24 as a precaution against roll motion of the vessel 10 that could otherwise dislodge the monopile 14. Similarly, a lifting tool 46 engaged with the top end 18 of the monopile 14 could be engaged temporarily with the upending frame 26, for example with trunnions of the lifting tool 46 engaging complementary formations of the upending frame 26 to sea-fasten the monopile 14 during transport. Again, this is further explained with reference to the second embodiment shown in Figures 3 and 4a to 4d.

[0049] During installation, the monopile 14 in the upending frame 26 is upended by the crane 12, which lifts the top end 18 of the monopile 14 opposed to the overboarding side 42 of the vessel 10. For this purpose, the lifting tool 46 suspended from a hook 48 of the crane 12 engages the top end 18 of the monopile 14. For example, the lifting tool 46 can clamp outwardly against an inner side of the tubular side wall of the monopile 14 and / or can clamp inwardly against an outer side of the side wall. The lifting tool 46 can also engage the monopile mechanically, for example by inter-engagement of complementary formations of the lifting tool 46 and the monopile 14.

[0050] The crane 12 then lifts the top end 18 of the monopile 14 via the lifting tool 46 and slews about a vertical slew axis 50. The crane 12 thereby carries the lifting tool 46 and the top end 18 of the monopile 14 toward the overboarding side 42 of the vessel 10, following the longitudinal plane of the upending frame 26 as the monopile 14 approaches a vertical orientation. Eventually, as shown in Figures 1b and 2b, the lifting tool 46 hanging from the hook 48 suspends the monopile 14 in the vertical orientation over the overboarding side 42 of the vessel 10.

[0051] In response to this movement of the monopile 14, the upending frame 26 tilts about the pivot axis 28. As the upending frame 26 tilts toward the vertical, the arms 36 of the lateral support frame pivot into a steeper inclination relative to the horizontal working deck 16. Thus, to adapt to the changing geometry of the linkage, the arms 36 pivot about the secondary axis 36 relative to the upending frame 26 and about the tertiary axis 38 relative to the working deck 16. Moreover, the bottom ends of the arms 36 slide or otherwise translate as they move across the working deck 16 toward the overboarding side 42 of the vessel 10. In this respect, the arms 36 are of fixed length but if the arms 36 were instead of variable length, the bottom ends of the arms 36 could, in principle, remain in fixed pivot positions relative to the working deck 16.

[0052] The tilting action of the upending frame 26 guides overboarding movement of the monopile

[0053] 14. In so doing, the tilting action swings a lower portion of the monopile 14, outboard of the pivot axis 28, directly into the embrace of a gripper 52 that is cantilevered from the overboarding side 42 of the vessel 10.

[0054] For this purpose, as is conventional, the gripper 52 comprises arms that are opened or splayed apart outwardly to receive the monopile 14 and that then close and come together to encircle the monopile 14 in substantially concentric relation. The gripper 52 cooperates with the crane 12 to keep the monopile 14 vertical when being landed on and driven into the seabed and could have active motion compensation to respond to motion of the vessel 10 caused by waves and swells.

[0055] Before landing the monopile 14 on the seabed, the crane 12 lifts the upended monopile 14 vertically out of the upending frame 26. If necessary, a bottom cradle of the upending frame 26 can be lifted by a few metres to allow the upending frame 26 then to be lowered freely back to the horizontal without clashing with the monopile 14. The monopile 14 is then landed or set down on the seabed and the lifting tool 46 is released from the top end 18 before being lifted by the crane 12 to a temporary holding station, conveniently on top of the upending frame 26.

[0056] In this example, as shown in Figures 2a and 2b, the working deck 16 of the vessel 10 also carries a pile-driving hammer 54 that the crane 12 can lift onto the top end 18 of the monopile 14 once the monopile 14 has been upended and landed on the seabed. The monopile 14 is thereby driven into the seabed to a final penetration depth, hence completing installation of the monopile 14, before the crane 12 lifts the hammer 54 back to its storage location on the working deck 16. The working deck 16 can also carry other wind turbine components to be added to each installed monopile 14, such as a transition piece to interface with the wind turbine mast.

[0057] When the crane 12 is available again, it can be used to lift one of the other monopiles 14A from the working deck 16 and into the upending frame 26. The crane 12 can then transfer the lifting tool 46 from its holding station into the top end 18 of that monopile 14, ready for the installation operation to be repeated when the vessel 10 has moved to another installation location.

[0058] In this embodiment, all operations of upending and pile-driving take place on the same overboarding side 42 of the vessel 10, optimising workability and leaving the other side of the vessel 10 free to moor alongside a quay to ease loading. The invention as exemplified in the foregoing description benefits from the use of an existing gripper 52 and from upending of the monopile 14 directly into the gripper 52. No skidding or hinging of the gripper 52 is required and the gripper 52 remains independent and free of the upending frame 26. Also, there is space for a noise mitigation system beneath the gripper 52.

[0059] The remaining drawings, namely Figures 3 and 4a to 4d, illustrate a second embodiment of the invention in which like numerals are used for like features. Figures 4a to 4c omit the gripper 52 but show the upending frame 26; conversely, Figure 4d shows the gripper 52 but omits the upending frame 26.

[0060] The main difference between the first and second embodiments can best be appreciated with reference to the plan view of Figure 3. Here, it can be seen that the gripper 52 and hence an installation side 56 of the vessel is opposed to the overboarding side 42. Consequently, a monopile 14 that is upended and overboarded on the overboarding side 42 of the vessel 10 is then transferred to the gripper 52 on the installation side 56 of the vessel 10.

[0061] Figures 4a to 4c show the crane 12 using a lifting tool 46 fixed to the top end 18 of the monopile 14 to lift the monopile 14 and the upending frame 26. The monopile 14 and the upending frame 26 are thereby lifted from the initial horizontal orientation shown in Figure 4a through the intermediate inclination shown in Figure 4b and into the upright orientation shown in Figure 4c, where the monopile 14 has been overboarded from the overboarding side 42 of the vessel 10 and disengaged from the upending frame 26. Figure 4d then shows the crane 12 slewed to convey the monopile 14 to the gripper 52 on the installation side 56 of the vessel 10.

[0062] More specifically, also referring back to Figure 3, the crane 12 lifts the upended monopile 14 from the upending frame 26 and then slews around the stern 58 of the vessel 10 to convey and guide the monopile 14 into the gripper 52, whose arms 60 are shown here open ready to receive and embrace the monopile 14. To ease entry of the monopile 14 after its movement around the stern 58, the mouth or entry of the gripper 52 is inclined relative to the installation side 56 on an axis 62 that extends not only outwardly away from the installation side 56 but also rearwardly toward the stern 58 of the vessel 10. Similarly, the upending frame 26 is inclined relative to the overboarding side 42 of the vessel 10 so that the central longitudinal axis 34 of the monopile 14 extends outwardly away from the overboarding side 42 and also rearwardly toward the stern 58. Consequently, the horizontal pivot axis 28 about which the upending frame 26 pivots is at an acute angle to the overboarding side 42 of the vessel 10 in plan view.

[0063] Figures 4b and 4c show aforementioned features of the first embodiment, also used in the second embodiment, in more detail. One such feature is the carriages 64 to which the inclined arms 36 straddling the upending frame 26 are pivotably attached at their bottom ends. The carriages 64 can translate across the working deck 16 on transverse rails as the crane 12 lifts the upending frame 26 and the monopile 14. In this example, the top ends of the arms 36 are pivotably attached to the upper side edges of the cradle 30 at the secondary pivot axis 38.

[0064] Another feature of the first embodiment, also used in the second embodiment, is the aforementioned engagement of the lifting tool 46 with the upending frame 26. In this respect, Figure 4c shows that the lifting tool 46 has horizontally-projecting trunnions 66 that engage in, and are cradled by, complementary socket formations 68 in the free end of the upending frame 26.

[0065] When the monopile 14 and the upending frame 26 are in horizontal or inclined orientations as shown in Figures 4a and 4b, the socket formations 68 are oriented to block upward movement of the trunnions 66 relative to the upending frame 26. This locks the lifting tool 46 and hence the monopile 14 to the upending frame 26. However, when the monopile 14 and the upending frame 26 reach the upright orientation shown in Figure 4c, the socket formations 68 are oriented to open upwardly. The trunnions 66 can then lift freely out of the socket formations 68 to allow the crane 12 to lift the lifting tool 46 and hence the monopile 14 out of engagement with the upending frame 26. The crane 12 is then free to slew to convey the monopile 14 into the gripper 52 as described above.

[0066] Many other variations are possible within the inventive concept. For example, a monopile could be overboarded over an end of a vessel such as its stern end. Similarly, a gripper could be situated at an end of the vessel, preferably the same end, such as its stern end.

[0067] The arms of the lateral support frame can pivot passively in response to upending movement of the monopile and the upending frame. Alternatively, pivoting or translational movements of the arms could be driven and / or locked to drive or to control those upending movements. The crane and the upending frame could be on different vessels. For example, a floating crane could be used beside a barge that supports a monopile on an upending frame of the invention.

Claims

Claims1. An upending system for upending an elongate element from aboard a vessel operating offshore, the system comprising: an upending frame that is pivotable with the element into an upright orientation about a substantially horizontal pivot axis, wherein the upending frame is arranged to support at least part of an upper portion of the element that extends between the pivot axis and a top end of the element; and a lifting tool that is engageable with the top end of the element, wherein the upending frame extends to and is engageable with the lifting tool.

2. The system of Claim 1 , arranged such that the lifting tool will disengage from the upending frame automatically in consequence of the upending frame reaching the upright orientation.

3. The system of Claim 1 or Claim 2, wherein the upending frame comprises socket formations that are arranged to receive trunnions protruding from the lifting tool.

4. The system of any preceding claim, further comprising a support frame that is pivotably connected at a first end to the upending frame, and that has a second end movable horizontally relative to a deck of the vessel.

5. The system of Claim 4, wherein the second end of the support frame is also pivotable relative to said deck of the vessel.

6. The system of Claim 4 or Claim 5, wherein the second end of the support frame is driven to move horizontally relative to said deck of the vessel.

7. The system of any of Claims 4 to 6, wherein the second end of the support frame is lockable against movement relative to said deck of the vessel.

8. An upending system for upending an elongate element from aboard a vessel operating offshore, the system comprising:an upending frame that is pivotable with the element into an upright orientation about a substantially horizontal pivot axis, wherein the upending frame is arranged to support at least part of an upper portion of the element that extends between the pivot axis and a top end of the element; and a support frame that is pivotably connected at a first end to the upending frame, and that has a second end movable horizontally relative to a deck of the vessel.

9. The system of Claim 8, wherein the second end of the support frame is also pivotable relative to said deck of the vessel.

10. The system of Claim 8 or Claim 9, wherein the second end of the support frame is driven to move horizontally relative to said deck of the vessel.

11. The system of any of Claims 8 to 10, wherein the second end of the support frame is lockable against movement relative to said deck of the vessel.

12. The system of any of Claims 8 to 11 , further comprising a lifting tool that is engageable with the top end of the element, wherein the upending frame extends to and is engageable with the lifting tool.

13. The system of Claim 12, arranged such that the lifting tool will disengage from the upending frame automatically in consequence of the upending frame reaching the upright orientation.

14. The system of Claim 12 or Claim 13, wherein the upending frame comprises socket formations that are arranged to receive trunnions protruding from the lifting tool.

15. The system of any of Claims 8 to 14, wherein the pivot axis is at a level above said deck of the vessel.

16. The system of any of Claims 8 to 15, wherein the pivot axis is outboard of said deck of the vessel.

17. The system of any of Claims 8 to 16, wherein when the upending frame is in the upright orientation, there is a vertical clearance between a lower end of the upending frame and a level of said deck.

18. The system of any preceding claim, wherein a lower end of the upending frame is aligned with the pivot axis.

19. The system of any preceding claim, wherein a centre of gravity of the element is disposed between the pivot axis and the top end of the element.

20. An installation vessel equipped with the upending system of any preceding claim.

21. The vessel of Claim 20, further comprising a gripper that is aligned with the upending frame to receive a lower portion of the element directly upon upending the element.

22. The vessel of Claim 20, further comprising a gripper on a side opposed to an overboarding side over which the upending frame overboards the upended element.

23. A method of upending an elongate element aboard a vessel operating offshore, the method comprising: engaging a lifting tool with a top end of the element; and engaging the lifting tool with an upending frame; and then pivoting the upending frame with the element into an upright orientation about a substantially horizontal pivot axis, while using the upending frame to support at least part of an upper portion of the element that extends between the pivot axis and the top end of the element.

24. The method of Claim 23, comprising disengaging the lifting tool from the upending frame automatically in consequence of the upending frame reaching the upright orientation.

25. The method of Claim 23 or Claim 24, comprising supporting the pivoting upending frame with a support frame while pivoting the support frame relative to the upending frame and moving the support frame horizontally relative to a deck of the vessel.

26. The method of any of Claims 23 to 25, preceded by transporting the element across water when aboard the vessel, with the lifting tool engaged with the top end of the element and with the upending frame.

27. A method of upending an elongate element aboard a vessel operating offshore, the method comprising: pivoting an upending frame with the element into an upright orientation about a substantially horizontal pivot axis, while using the upending frame to support at least part of an upper portion of the element that extends between the pivot axis and a top end of the element; and supporting the pivoting upending frame with a support frame while pivoting the support frame relative to the upending frame and moving the support frame horizontally relative to a deck of the vessel.

28. The method of Claim 27, comprising also pivoting the support frame relative to said deck of the vessel.

29. The method of Claim 27 or Claim 28, comprising driving movement of the support frame horizontally relative to said deck of the vessel.

30. The method of any of Claims 27 to 29, comprising locking the support frame against movement relative to said deck of the vessel.

31. The method of any of Claims 27 to 30, comprising engaging a lifting tool with the top end of the element and engaging the lifting tool with the upending frame before lifting the top end of the element.

32. The method of Claim 31 , comprising disengaging the lifting tool from the upending frame automatically in consequence of the upending frame reaching the upright orientation.

33. The method of any of Claims 23 to 32, comprising overboarding the upended element directly into a gripper supported by the vessel.

34. The method of any of Claims 23 to 32, comprising overboarding the upended element and then conveying the upended element horizontally into a gripper supported by the vessel.

35. The method of any of Claims 23 to 34, wherein the element is a monopile, a jacket foundation or a wind turbine mast.

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