GB2619106A

GB2619106A - Offshore turbine assembly method

Info

Publication number: GB2619106A
Application number: GB2214097.4A
Authority: GB
Inventors: John Whyte Charles; William Henry West Alan; Stephen Giles John
Original assignee: Planet 42 Ltd
Current assignee: Planet 42 Ltd
Priority date: 2022-04-04
Filing date: 2022-09-27
Publication date: 2023-11-29
Also published as: GB202303196D0; GB2628869A; GB2619788A; GB202308222D0; GB202209710D0; GB2619358A; GB202204907D0; GB202214097D0

Abstract

An apparatus (5, Fig.1) for assembling a structure such as an offshore structure (10, Fig.4), wind turbine or jacket, comprising an erectable structure (15, Fig.1) and a post or column configured to extend through a central portion of the erectable structure. The erectable structure (15, Fig.1) may take the form of a tripod, and the central portion of the structure may be ‘walked up’ the post or column during erection of the structure. Also disclosed is a method of erecting an erectable structure (15, Fig.1) comprising providing an erectable structure; providing a post or column configured to extend through a central portion of the erectable structure; and raising a central portion of the erectable structure relative to the post or column.

Description

IMPROVEMENTS IN AND RELATING TO ASSEMBLING A STRUCTURE

FIELD OF INVENTION

The present invention relates to a device/apparatus and/or a system for assembling a structure, such as an (offshore) structure or (offshore) wind turbine or (offshore) jacket. The present invention also relates to a method of deploying a device/apparatus or system for assembling an (offshore) structure, such as an offshore structure, or (offshore) wind turbine or (offshore) jacket. The present invention also relates to a method of assembling a structure or (offshore) turbine(s) or jacket, such as a wind turbine(s) or jacket, e.g., an offshore wind turbine(s) or offshore jacket. The structure is beneficially a floating/buoyant structure and/or is provided on a floating/buoyant body.

In particular, though not exclusively, the invention relates to a method of assembling, e.g., at an offshore location, a wind turbine structure or jacket, e.g., intended for offshore use, and to apparatus for assembling a wind turbine or jacket.

BACKGROUND TO INVENTION

In the field of wind turbines, in particular offshore wind turbines, there is a general trend towards installing increasingly high power-output wind turbines, for example, turbine capable of outputting 10 Mega Watts or more. However, along with increased power capabilities, the physical dimensions of such wind turbines are also increasing. Historically, wind turbines, or at least assembled or semi-assembled components of wind turbines, may have been manufactured and/or assembled at a first location, then transported by road to a further location for deployment and/or further assembly.

However, due to their increased physical dimensions, transport by road of modern turbines, or assembled portions of modern turbines, is no longer practically possible.

At present, wind turbines and their associated structures may be separately constructed onshore and transported in sections to an offshore site. There, such may be moved into position and fixed using slings and cranes.

This background serves to set a scene to allow a skilled reader to better appreciate the following description. Therefore, none of the above discussion should necessarily be taken as an acknowledgement that that discussion is part of the state of the art or is common general knowledge.

Further background material includes GB 2479232 B (W3G SHIPPING LTD), which describes structures, such as wind turbine structures for offshore sites, comprising transport elements, e.g., an annular protrusion configured for complementary mating with engagement portions of a clamp, which allow for transporting of the structures using that clamp. The clamp may comprise two or more portions, which are positioned around the structure. A wind turbine may be transported as a completed structure. Generally, the transport element is provided at an attachment region of a tower, or the like, where the tower would attach to a support, such as a jacket. There is also described apparatus for allowing for transport of a wind turbine structure, comprising a clamp. In some cases, the apparatus is also configured so as to modify the effective centre of gravity of an associated structure, and/or the effective centre of inertia of an associated structure. An orientation assembly comprising six actuators controlled by the use of positioning signals may be provided to allow relative movement of the clamp, and thus the clamped structure, with respect to a lifting device. A crane may transport a wind turbine to/from a barge.

GB 2479232 B (VV3G SHIPPING LTD) discloses a system, such as an offshore system, the system comprising: a wind turbine structure for a site, such as an offshore site. The structure comprises a tower for supporting a turbine and a transport element, the transport element being provided at a base of the tower and being part of a complementary mating arrangement, wherein the transport element is mateable with an engagement element of a clamp; and an apparatus for allowing for transport of the structure, the apparatus comprising the clamp having the engagement element, the engagement element being another part of the complementary mating arrangement, the engagement element being mateable with the transport element of the tower; and wherein when the engagement element of the clamp is mated with the transport element of the tower, the apparatus is configured to allow for lifting and lowering of the structure at the site from the base of the tower using the clamp.

GB 2582844 B (VV3G MARINE LTD) discloses a method of assembling a structure, such as a wind turbine, the method comprising the steps of: providing a lifting arrangement comprising: a gantry disposed over and/or directly above a rail or rails; and lifting means coupled to the gantry; and stacking portions of the structure by: conveyably disposing a first portion of the structure relative to the rail or rails by: lifting the first portion using the lifting means; configuring a clamping device to grip the first portion; and conveying the clamping device along the rail or rails; lifting a second portion of the structure using the lifting means; disposing the first portion underneath the second portion by further conveying the first portion gripped by the clamping device along the rail or rails; and lowering the second portion onto the first portion.

One or more aspects/embodiments of the invention may or may not address one

or more of the background issues.

It is an object of at least one embodiment of at least one aspect of the present invention to obviate or at least mitigate at least one problem in the prior art.

It is an object of at least one embodiment of at least one aspect of the present invention to provide a technically simple and/or commercially more cost-effective method and system for assembling an (offshore) wind turbine structure or (offshore) jacket, e.g., for an (offshore) wind turbine, than in the prior art.

SUMMARY OF INVENTION

According to the present invention there is provided a device or apparatus and a system for assembling an (offshore) structure (such as a wind turbine or wind turbine generator (WTG)), a method of deploying a device or apparatus for assembling an (offshore) structure, and a method of assembling an (offshore) structure according to the appended claims.

According to a first aspect of the present invention there is provided a device or apparatus for assembling a structure (such as wind turbine or jacket, such as an offshore structure, wind turbine or jacket), the apparatus comprising a (erectable, e.g., vertically erectable) structure and a lifting arrangement.

The structure may be capable of being erected or assembled, e.g., in situ, and/or capable of being takedown or disassembled, e.g., in situ.

The device/apparatus may comprise or provide an assembly area, e.g., an area of water, e.g., above a bed or floor of a body of water, e.g., a seabed. The assembly area may be provided below the lifting arrangement, e.g., when erected. It will be appreciated that the device/apparatus can be used offshore or on land, e.g., on or at a quayside. The assembly area may be provided within a perimeter, area or volume of the device or apparatus. The lifting arrangement may be provided above, e.g., directly above, the assembly area.

In one embodiment, the (erectable) structure may be disposable in a first or collapsed state. The erectable structure may be disposable in a second, expanded or erected state. The erectable structure may be expandable or selectively movable from a/the first state to a/the second state. The erectable structure may be collapsible or further selectively movable from a/the second state to a/the first state. This selective disposition may facilitate the erectable structure being transported in a collapsed state to a location for assembling the (offshore) structure and then when at the location being expanded and erected. Further, this selective disposition may facilitate the erectable structure being collapsed and/or removed from the assembly area after the (offshore) structure has been assembled.

In another embodiment, the structure may be capable of being assembled and/or erected at site or in situ. This embodiment facilitates parts of the structure being transported to site individually or at least not assembled for assembly on or at site.

The structure may comprise a plurality of legs and/or an apex member. The legs may be connected to or connectable to the apex member.

The lifting arrangement may, in use, be provided below, e.g., directly below the apex member. The lifting arrangement may depend from the apex. The assembly area may be provided below, e.g., directly below, the apex.

In one preferred embodiment, the device or apparatus may comprise a tripod or tripod arrangement or comprise three legs. The tripod may comprise three legs.

Alternatively, the device or apparatus may comprise a tetrapod.

Each of the legs may be attached, e.g., hingably attached, at a first end to a connection member. The connection member may comprise an apex of the structure/tripod/tetrapod. The lifting arrangement may be attached to and/or depend (vertically downwardly) from the connection member or apex. In this manner, the lifting arrangement may be provided between the three legs.

Each leg may be provided at a second end with a mud mat. The/each mud mat may be selectively buoyant (for transportation) or submersible (for erection).

In some embodiments, e.g., in the case of a tetrapod, a pair of opposing legs may be of a same length, which length may be different to another pair of opposing legs.

The structure may when erected comprise a pyramid shape, e.g., a pyramid having a polyhedral base, triangular base, square base or rectangular base, The structure may when erected comprise a tetrahedron.

The lifting arrangement may comprise an arrangement for connecting or supporting a part(s) of the structure to be lifted. The arrangement may comprise one or more hooks, shackles or the like. The lifting arrangement may comprise a single point lifting arrangement, e.g., comprising a single lifting point for supporting a load, e.g., part or component of the structure.

The lifting arrangement may comprise one or more pulley arrangements and/or winches.

One or more lines (control/mooring/tagging lines) may be provided between at least one and preferably each of the legs, the lines being adapted to be connected to a load (e.g., part of the structure) being lifted by the lifting arrangement. A connection piece may be provided at an intersection point of the lines, e.g., below the apex member.

One or more of the legs of the device or apparatus may comprise a (metal) lattice arrangement.

At or near ends of the legs distal the apex member, there may be provided further lines or cables between adjacent legs.

Yet further lines may be provided at or near end of each leg, which further lines extend (horizontally) so as to meet at a (base) centre point of the apparatus, e.g., below the apex member.

In a modified embodiment the device/apparatus at least one or each leg may be provided with a support member. The/each support member may be provided at or near a respective end of one of the legs distal the apex. The/each support member may be deployed in a substantially vertical disposition, in use. The support member may impart support/strength to the respective leg so as to seek to avoid buckling of the leg. According to a second aspect of the present invention there is provided a system for assembling a structure (such as wind turbine or jacket, such as an offshore structure, wind turbine or jacket), the system comprising a device according to the first aspect of the present invention.

The system may comprise a floating or buoyant body for transporting one or more pails of the structure to the assembly area.

The system may comprise one or more winches, e.g., for controlling the lifting arrangement.

The one or more winches may be provided on a further floating or buoyant body.

The further floating or buoyant body may be adapted to be secured to a leg of the device or apparatus. For example, the further floating or buoyant body may comprise a slotted or recessed portion for engagement with a leg of the device or apparatus and/or for receiving the connection member during transportation of the device/apparatus when in a collapsed state.

According to a third aspect of the present invention there is provided a method of deploying a device or apparatus for assembling a structure such as a wind turbine, such as an (floating/buoyant) offshore structure, wind turbine or jacket, the method comprising: providing at or to an assembly area or location a device or apparatus according to the first aspect of the present invention; and deploying/erecting the device or apparatus.

Preferably the assembly location is an area of water, e.g., an area above a bed or floor of a body of water, e.g., a seabed.

The device/apparatus when erected may stand/sit on a bed of a body of water, e.g., a seabed. The apex and the lifting arrangement may be provided above a surface level of the body of water.

The step of providing the device or apparatus to the assembly location may comprise use of one or more vessels or barges, e.g., to transport the device or apparatus or one or more parts/components thereof, whether together or individually.

According to a fourth aspect of the present invention there is provided a method of assembling a structure or wind turbine, such as an offshore structure, wind turbine or jacket, the method comprising: deploying the device or apparatus according to a method according to the third aspect of the present invention; transporting a first part of the structure to the assembly area; lifting the first part using the lifting arrangement; transporting a floating/buoyant base or foundation body to the assembly area; connecting/clamping the first part of the structure to the floating/buoyant base body The method may comprise the subsequent step(s) of: transporting a further part of the structure to the assembly area; lifting the further part using the lifting arrangement; transporting the floating/buoyant base to the assembly area; lowering and/or connecting the further part of the structure to the first/a part of the structure already provided on the floating/buoyant base.

The structure may be a floating structure.

The structure may comprise or include: a plurality of parts or components; a segmented (offshore) structure; a floating/buoyant foundation; a monopile; a jacket, e.g., a three-leg jacket, a four-leg jacket or a twisted jacket.

In the case of the structure comprising a wind turbine, (the) parts or components may comprise on or more of: column or tower, e.g., first and second column parts; a nacelle; a plurality of turbine blades, e.g., three turbine blades.

In such case, there could be a given number of parts, e.g., six parts, and so a requirement for a same given number of lifts, e.g., six lifts.

The method may comprise a tower for supporting (parts of) the structure during assembly.

There may be provided an arrangement for extending or increasing a height of the tower, in use, e.g., in intervals, so as to lift the structure and/or apex of the structure.

According to a fifth aspect of the present invention there is provided a method of assembling an (offshore) structure, such as an (offshore) wind turbine or (offshore) jacket, the method comprising the steps of: providing a lifting arrangement comprising: a gantry disposed over and/or directly above an area of water. and a lifting means or apparatus coupled to the gantry; and stacking portions of the structure by: conveyably disposing a first portion of the structure relative to or at the area of water: lifting the first portion using the lifting means; configuring a clamping or retaining device to grip the first portion; and conveying the clamping or retaining device away from the area of water; lifting a second portion of the structure using the lifting means disposing the first portion underneath or adjacent the second portion by further conveying the first portion gripped by the clamping device to the area of water; and lowering the second portion onto or so as to connect with the first portion.

The step of lifting the second portion using the lifting means or apparatus may comprise hoisting and/or raising the second portion in an upwards direction to a height above an uppermost level of first portion.

The method may comprise a step of fixedly coupling the second portion to the first portion by bolting, welding, and/or clamping.

The structure may be a wind turbine assembly, such as an offshore wind turbine, or a jacket, such as an offshore jacket, e.g., for supporting a wind turbine.

The first portion and/or the second portion and/or one or more further portion(s) may be at least one of: a portion of a tower or a nacelle or a turbine blade(s).

The method may further comprise the step of stacking a/the further portion on the second portion by: lifting the further portion using the lifting means or apparatus; disposing the second portion of the structure underneath the further portion by conveying the second portion to the area of water; lowering the further portion onto or relative to the second portion.

The clamping device may be provided on a floating or buoyant body, e.g., a floating foundation or (top) crown assembly.

The clamping device may be configured for supporting and/or clamping and/or gripping at least a portion of the structure in a vertical disposition and/or substantially upright configuration.

According to a sixth aspect of the present invention there is provided a system for assembling a structure, such as an (offshore) wind turbine or (offshore) jacket, the system comprising: a gantry disposed over and/or directly above an area of water; a lifting means or arrangement coupled to the gantry; and a means or device for conveying a portion of the structure to and from the area of water, wherein the means or device for conveying a portion of the structure comprises a clamping or retaining device.

The clamping or retaining device may be configurable between a clamping or retention configuration for gripping a portion of the structure and a non-clamping or non-retention configuration.

The clamping device may be coupled to or mounted on a floating or buoyant (base) body, e.g., a floating foundation or (top) crown assembly or barge.

The lifting means may comprise a winch and/or a pulley.

The system may be adapted for assembling a wind turbine assembly or a jacket, such as an offshore wind turbine assembly or an offshore jacket assembly, e.g., for a wind turbine.

The system may comprise a clamping and/or gripping system comprising: the clamping device for gripping at least a portion of a wind turbine assembly; and a/the floating or buoyant body, wherein the clamping device is mounted on the floating or buoyant body.

The clamping device may be configured for supporting at least a portion of a wind turbine assembly or jacket assembly in a vertical disposition and/or substantially upright configuration.

The clamping device may be configured to engage with a flange or rim disposed on an outer surface of the portion of the structure.

According to a seventh aspect of the present invention there is provided a device or apparatus for assembling a structure (such as wind turbine or jacket, such as an offshore structure, wind turbine or jacket), the device or apparatus comprising an erectable, e.g., vertically erectable structure. The device or apparatus may comprise a lifting arrangement. Also disclosed is a method of erecting the erectable structure, and a system comprising the erectable structure.

The erectable structure may comprise a multi-legged structure, e.g. a tripod or tetrapod or the like.

In one embodiment, the erectable structure may be disposable in a first or collapsed state. The erectable structure may be disposable in a second, expanded or erected state. The erectable structure may be expandable or selectively movable from a/the first state to a/the second state. The erectable structure may be collapsible or further selectively movable from a/the second state to a/the first state. This selective disposition may facilitate the erectable structure being transported in a collapsed state to a location for assembling the (offshore) structure and then when at the location being expanded and erected. Further, this selective disposition may facilitate the erectable structure being collapsed and/or removed from the assembly area after the (offshore) structure has been assembled.

In examples, erection of the erectable structure may be assisted by a post or column. The post or column may be mounted on a floating structure. The post or column may extend through a central portion of the erectable structure.

During a process of erection of the erectable structure, a central portion of the erectable structure may be raised relative to, e.g. 'walked' up, the post or column. The central portion may comprise a running gear module.

Such raising of the central portion of the erectable structure comprises use of one or more clamps, such as a walking clamp.

In some examples, while the central portion of the erectable structure is being raised, a pulling force may be applied to tension members, e.g. lines, between a centre and a base (or generally towards a base) of legs of the erectable structure.

In some examples, while the central portion of the erectable structure is being raised, a pulling force may be applied to tension members, e.g. lines, between the bases of the legs of the erectable structure.

The post may be provided initially on a floating structure with the top of the erectable structure placed around the post or column.

In examples, the erectable structure and/or the post or column may be initially provided in pieces that may be assembled, e.g. joined together, on deck.

In examples, the erectable structure may be installed in pieces that are then joined together on the deck and/or lowered over the top of, and/or assembled around, the post or column.

In some examples, the floating structure, or at least a portion thereof, may be lowered to and/or extended to the seabed to provide a reaction to lift the erectable structure into position.

In some examples, the floating structure may be floating during erection of the erectable structure, e.g. providing there is sufficient buoyancy and stability capacity to react the loads.

In some embodiments, the post or column may be fitted with one or more winches, e.g. linear winches, at an upper or top portion.

The one or more winches may be configured to lift an upper or top portion of the erectable structure.

In embodiments, the post or column may be provided with one or more return sheaves with winches at, on, or in the general proximity of, the deck, e.g. a deck of the floating structure.

The post or column may be a primary post or column and may comprise at least one further post or column disposed inside the primary post or column. The primary post or column and the at least one further post or column may be arranged in a telescopic arrangement.

During assembly of the erectable structure, when an upper portion or top of the erectable structure is raised to reach the top or upper portion of the post or column, then the at least one further post or column may be extended, e.g. telescoped, to continue with a process of raising the upper portion or top of the erectable structure.

In some examples, the erectable structure may be erected without any lifting machinery in place, e.g. lifting machinery that may be required for assembling the structure, such as the wind turbine or jacket or offshore structure, offshore wind turbine or offshore jacket.

In such examples, the lifting machinery may be lifted into place, e.g. at an upper portion of the erectable structure, following erection of the erectable structure.

In some examples, the erectable structure may have some of its structural components lifted into place following the initial erection of the structure. In an example, such structural components may also form part of a platform for the lifting machinery.

In examples of use, the lifting machinery may be configured to be lowered and/or removed, such as for purposes of servicing, maintenance, repair, preservation and the like.

In some examples, a windage of the erectable structure may be reduced by removing at least a portion of the erectable structure, and in particularly an upper portion of the erectable structure. As an example, roofs or safe areas for personnel that may only be required during operations may be removed to reduce the windage.

In some examples, one or more parts or components of the erectable structure that are lifted after an initial erection of the erectable structure may be used to increase a stiffness of the erectable structure, in order to reduce a propensity to buckling.

In some examples, such as when the erectable structure comprises a tripod, there may be provided a mud-mat barge at a base portion of each leg. Such barges may be fitted with buoyancy that may extend from their deck and, when on the seabed, their tops or upper portions may be substantially at or above a waterline. Advantageously, this may assist with the sinking of the mud-mat barges into place.

In some examples, the mud-mat barges may be ballasted such that said mud-mad barges provide lateral stability from forces, e.g. wind and/or tidal forces, during their operations. In some example, such ballast may be achieved by at least one of: pumping in water or other higher density material to provide a gravity anchor, e.g. mud or haematite; sheet piles around the mud-mat barge; piled anchors; suction anchors; anchors attached by chain; wire or rope; and/or securing lines to the shore.

According to a second aspect of the present invention there is provided a system for assembling a structure (such as wind turbine or jacket, such as an offshore structure, wind turbine or jacket), the system comprising a device or apparatus according to the seventh aspect of the present invention.

The above summary is intended to be merely exemplary and non-limiting. The disclosure includes one or more corresponding aspects, embodiments or features in isolation or in various combinations whether or not specifically stated (including claimed) in that combination or in isolation. It should be understood that features defined above in accordance with any aspect of the present disclosure or below relating to any specific embodiment of the disclosure may be utilized, either alone or in combination with any other defined feature, in any other aspect or embodiment or to form a further aspect or embodiment of the disclosure.

BRIEF DESCRIPTION OF DRAWINGS

Embodiments of the present invention will now be described, by way of example only, and with reference to the accompanying drawings, which are: Figure 1 a schematic view of an apparatus for assembling an offshore structure according to a first embodiment of the present invention, the apparatus being in transit to an offshore assembly/installation area; Figures 2(a) to (e) a series of views of the apparatus of Figure 1 being deployed at an offshore location comprising an area of water; Figures 3(a) and (b) views of the apparatus deployed at an area of water; Figure 4 a view of the apparatus of Figure 1 with an offshore structure erected at the area of water; Figure 5 a detailed view of an apex of the erected apparatus of Figure 4; Figures 6(a) to (e) a series of schematic drawings showing a sequence of steps in erecting the offshore structure of Figure 4; Figure 7(a) to (c) schematic drawings of steps in a sequence in erecting an offshore structure using an apparatus for assembling an offshore structure according to a second embodiment of the present invention; Figures 8(a) and (b) schematic drawings of steps in a sequence in erecting an alternative offshore structure using the apparatus of Figure 1; Figures 9(a) to (c) a front view, a perspective view from one side and above, and an in situ view of an offshore wind turbine assembled using a device/apparatus according to the present invention; Figures 10(a) told) a side view, a perspective view from one side and above, a further perspective view from one side and above, and a yet further perspective view from one side an above with an offshore wind turbine in situ of an apparatus according to a third embodiment of the present invention; Figures 11(a) to (c) a perspective view and side views of main and auxiliary lifting gear of the apparatus of Figures 10(a) to (d); Figures 12(a) to (d) a series of views of tagging winches of the apparatus of Figures 10(a) to (d); Figures 13(a) to (i) a series of views illustrating the erection or elevation of the apparatus of Figures 10(a) to (d); Figure 14 a side view with an offshore wind turbine in situ of an apparatus according to a fourth embodiment of the present invention; Figure 15a a perspective view of a running gear module, according to an

embodiment of the disclosure; and

Figure 15b a line drawing of the running gear module of Figure 15.

DETAILED DESCRIPTION OF DRAWINGS

Referring initially to Figures 1 to 6(e), there is shown a device/apparatus, generally designated 5, according to a first embodiment of the present invention. The device/apparatus 5 is adapted for assembling an offshore structure 10 (see Figures 4 and 6(e)) such as a wind turbine or (offshore) wind turbine (generator).

In this embodiment the device/apparatus 5 is used in assembling the structure 10 which is an offshore wind turbine. It will, however, be appreciated that the structure may be another offshore structure, e.g., an offshore jacket. The device/apparatus 5 comprises an (vertically) erectable structure 15 and a lifting arrangement 20.

The device/apparatus 5 comprises or provides an assembly area 25, e.g., on a surface of an area of water, below the lifting arrangement 20, e.g., when erected. Alternatively, the assembly area can be on a surface of an area of land/ground, e.g., a quayside. The assembly area 25 is provided within a perimeter, area or volume of the device/apparatus 5. The lifting arrangement 20 is provided above the assembly area 25, an beneficially directly above the assembly area 25.

The erectable structure 15 is disposable in a first or collapsed state (see Figure 1). The first state facilitates moving or transport of the device/apparatus 5. The erectable structure 15 is disposable in a second or expanded or erected state ((see Figures 3(a) to 6(e)). The erectable structure 15 is expandable or selectively movable from a/the first state to a/the second state. The erectable structure 15 is collapsible or further selectively movable from a/the second state to a/the first state. This selective disposition facilitates the erectable structure 15 being transported in a collapsed state to a location for assembling the structure 10, i.e., to the assembly area, and then when at the location being expanded and erected. Further, this selective disposition may facilitate the erectable being collapsed and/or removed from the assembly area 25 after the structure has been assembled.

In another embodiment (see Figures 8(a) to 130)), the structure can be capable of being assembled and/or erected at site or in situ. This embodiment facilitates parts of the structure being transported to site individually or at least not assembled for assembly on site.

The structure 15 comprise a plurality of legs 35, 36, 37 and/or an apex (member) 50. The legs 35, 36, 37 are connected to or connectable to the apex (member) 50.

The lifting arrangement 20 is, in use, provided below, e.g., directly below the apex (member) 50.

In this preferred embodiment, the device/apparatus 5 comprises a tripod 30 or tripod arrangement. Alternatively, the device/apparatus 5 can comprise a tetrapod. The tripod 30 comprises three legs 35, 36, 37. Each of the three legs 35, 36, 37 is attached, e.g., hingably attached, at a first end 40 to a connection member 45. The connection member 45 comprises an apex 50 of the tripod 30. The lifting arrangement 20 is attached to and/or, in use, depends (vertically downwardly) from the connection member 45 or apex 50. In this manner, the lifting arrangement 20 is provided between the three legs 35, 36, 37. Each leg 35, 36, 37 is provided at a second end with a mud mat 38. The/each mud mat 38 can be selectively buoyant or submersible.

The lifting arrangement 20 comprises an arrangement 55 for connecting or supporting a part(s) of the offshore structure 10 to be lifted. The connection arrangement comprises one or more hooks, shackles or the like. The lifting arrangement 20, therefore, provides a single point lifting arrangement, e.g., comprising a single lifting point for supporting a load such as a part/component of the structure 10.

The lifting arrangement 20 comprises one or more pulley arrangements 60 and/or winches.

Referring to Figures 7(a) and (c), there is shown a device/apparatus 5a according to a second embodiment of the present invention. The device/apparatus 5a of the second embodiment is similar to the device/apparatus 5 of the first embodiment, like parts be identified by like numerals but suffixed "a".

In the device/apparatus 5a, one or more lines 65a, 66a, 67a (control/mooring/tagging lines) are provided between at least one and preferably each of the legs 35a, 36a, 37a, the lines being adapted to be connected to a load (e.g., part of the structure) being lifted by the lifting arrangement.

Referring to Figures 8(a) and (b), there is shown a device/apparatus 5 according to the first embodiment of the present invention. In this example, the device/apparatus is used to assemble an offshore jacket 12.

In both the first and second embodiments, the legs 35, 36, 37; 35a, 36a, 37a of the device/apparatus 5; 5a comprise a (metal) lattice arrangement.

Referring now to Figures 9(a) to 130), there is shown a device/apparatus 5b according to a third embodiment of the present invention. The device/apparatus 5b of the third embodiment is similar to the device/apparatus 5 of the first embodiment, like parts being identified by like numeral but suffixed "b".

In the device/apparatus 5b, the components of the device/apparatus are assembled at site, i.e., at the assembly area 25b.

A connection piece 68b is provided at an intersection of the lines 65a, 66b, 67b.

At or near ends of the legs 35b, 36b, 37b distal the apex 50b, there are provided further lines or cables 145b extending peripherally between adjacent legs 35b, 36b, 37b.

Yet further lines 150 are provided at or near end of each leg 35b, 36b, 37b, which further lines 35b, 36b, 37h extend (horizontally) so as to meet at a (base) centre point of the device/apparatus 5b, e.g., below the apex 50b.

In this embodiment auxiliary winches 75'b are provided.

The present invention provides a system for assembling an offshore structure (such as wind turbine or jacket, such as an offshore structure, wind turbine or jacket), the system comprising a device/apparatus 5; 5a; 5b.

The system comprises a floating or buoyant body/bodies 70 for transporting one or more parts of the offshore structure to the assembly area 25.

The system comprises one or more winches 75, e.g., for controlling the lifting arrangement.

The one or more winches 75 can be provided on a further floating or buoyant body 80. The further floating or buoyant body 80 is adapted to be secured to a leg 35 of the device/apparatus 5. For example, the further floating or buoyant body 80 comprises a slotted or recessed portion 85 for engagement with a leg 35 of the device/apparatus 5. The slotted portion 85 can also receive the connection member during transportation of the device/apparatus when in a collapsed state.

The present invention provides a method of deploying a device/apparatus 5; 5a; 5b for assembling an (offshore) structure 10, such as a wind turbine, such as an (floating/buoyant) offshore structure, wind turbine or jacket. The method comprises: providing at or to an assembly area 25 or location a device/apparatus 5; 5a; 5b and deploying/erecting the device/apparatus 5; 5a.

In the disclosed embodiments the assembly area 25; 25a; 25b or location is an area of water. Also, in the disclosed embodiments, the device/apparatus 5; 5a; 5b when erected stands/sits on a bed of a body of water 86, e.g., a seabed 90. Also, the apex 50 and the lifting arrangement 20 are provided above a surface level 95 of the body of water 86.

The step of providing the device/apparatus 5; 5a; 5b to the assembly area 25; 25a; 25b comprises use of one or more vessels or barges 100.

The present invention provides a method of assembling a structure or wind turbine, such as an offshore structure 10, wind turbine or jacket. The method comprises: deploying the device/apparatus 5; 5a; 5b according to the aforementioned method; transporting a first part 105 of the offshore structure 10 to the assembly area; lifting the first part 105 using the lifting arrangement 20; transporting a floating/buoyant base or foundation body 110 to the assembly area 25; connecting/clamping the first part 105 of the structure 10 to the floating/buoyant base body.

The method may comprise the subsequent step(s) of transporting a further part of the structure 10 to the assembly area 25; lifting the further part using the lifting arrangement 20; transporting the floating/buoyant base body to the assembly area 25; lowering and/or connecting the further part of the structure to the first/ a part of the structure already provided on the floating/buoyant base body 110.

The structure 10 (including the floating base body 110) is a floating structure.

The structure 10 comprises or includes: a plurality of parts or components; a segmented (offshore) structure; a floating/buoyant foundation; a monopile; a wind turbine (see Figures 4 and 6(a) to 6(e) or Figures (a) to 7(c)); a jacket (see Figures 8(a) and (b)), e.g., a three-leg jacket, a four-leg jacket or a twisted jacket.

In the case of the structure 10 comprising a wind turbine, the parts comprise on or more of: column or tower, e.g., first and second column parts 115, 120 (e.g., around 400-500 tonnes each); a nacelle 125 (e.g., around 60 tonnes); a plurality of turbine blades, e.g., three turbine blades 130, 131, 132 (e.g., around 60 tonnes each).

In such case, there are a given number of parts (six) and so a requirement for a same given number of lifts (six).

In the embodiment shown in Figures 9(a) to 130), the method comprises using a tower 140 for supporting (parts of) the structure during assembly.

There is provided an arrangement for extending or increasing a height of the tower 140, in use, e.g., in intervals, so as to lift the structure 10b and/or apex 50b of the structure 10b, e.g., the tower may be telescopic.

Typically, blades 130, 131, 122 will be lifted horizontally.

According to the present invention there is provided a method of assembling an (offshore) structure 10, such as an (offshore) wind turbine or (offshore) jacket. The method comprises the steps of: providing a lifting arrangement 20 comprising: a gantry disposed over and/or directly above an area of water and a lifting means or apparatus coupled to the gantry; and stacking portions of the structure 10 by: conveyably disposing a first portion of the structure 10 relative to or at the area of water: lifting the first portion using the lifting means; configuring a clamping or retaining device 135 to grip the first portion; and conveying the clamping or retaining device away from the area of water; lifting a second portion of the structure 10 using the lifting means or apparatus; disposing the first portion underneath or adjacent the second portion by further conveying the first portion gripped by the clamping device 135 to the area of water; and lowering the second portion onto or so as to connect with the first portion.

The step of lifting the second portion using the lifting means or apparatus comprises hoisting and/or raising the second portion in an upwards direction to a height above an uppermost level of first portion.

The method comprises a step of fixedly coupling the second portion to the first portion by bolting, welding, and/or clamping.

The structure 10 can be a wind turbine assembly, such as an offshore wind turbine, or a jacket, such as an offshore jacket, e.g., for supporting a wind turbine.

The first portion and/or the second portion and/or one or more further portion(s) can be at least one of: a portion of a tower or a nacelle or a turbine blade(s).

The method further comprises the step of stacking a/the further portion on the second portion by: lifting the further portion using the lifting means; disposing the second portion of the structure underneath the further portion by conveying the second portion to the area of water; lowering the further portion onto the second portion.

The clamp 135 or clamping device is configured for supporting and/or clamping and/or gripping at least a portion of the structure 10 in a vertical disposition and/or substantially upright configuration.

The present invention provides a system for assembling a structure 10, such as an (offshore) wind turbine or (offshore) jacket. The system comprises: a gantry disposed over and/or directly above an area of water; lifting means coupled to the gantry; and means for conveying a portion of the structure 10 to and from the area of water, wherein the means for conveying a portion of the structure comprises a clamping or retaining device 135.

The clamping or retaining device 135 is configurable between a clamping or retention configuration for gripping a portion of the structure 10 and a non-clamping or non-retention configuration.

The clamping device 135 is coupled to or mounted on a floating or buoyant base body 110, e.g., a floating foundation or (top) crown assembly or barge.

The lifting means comprise a winch(es) 75 and/or a pulley or pulley arrangement 60.

The system is adapted for assembling a wind turbine assembly or a jacket, such as an offshore wind turbine assembly or an offshore jacket assembly, e.g., for a wind turbine.

The system comprises a clamping and/or gripping system comprising: the clamping device 135 for gripping at least a portion of a wind turbine assembly; and a/the floating or buoyant base body 110, wherein the clamping device is mounted on the floating or buoyant base body 110.

The clamping device 135 is configured for supporting at least a portion of a wind turbine assembly or jacket assembly in a vertical disposition and/or substantially upright configuration.

The clamping device 135 is configured to engage with a flange or rim disposed on an outer surface of the portion of the structure 10.

Referring now to Figure 14, there is shown a device/apparatus Sc according to a fourth embodiment of the present invention. The device/apparatus Sc of the fourth embodiment is similar to the device/apparatus 5 of the first embodiment, like parts being identified by like numeral but suffixed "b".

In the device/apparatus Sc of the fourth embodiment each leg 35c, 36c, 37c is provided with a support member 38. The three support members 38 are provided at or near a respective end of the leg 35c, 36c, 37c distal the apex 50c. Each support member 38 is deployed in a substantially vertical disposition, in use. The support member imparts support/strength to the respective leg 35c, 36c, 37c so as to seek to avoid buckling of the leg 35c, 36c, 37c.

With regard to various embodiments of the present invention, the reader will note the following: 1. The system creates a single point sufficiently high to lift the nacelle 125 onto the top of the column of a floating wind turbine. This is anticipated to be around 220m above sea level.

2. The single point lift may have multiple hooks with different capacities -for instance 1,000 tons and 120 tons. These would be suspended from the same location under the lifting point on possibly a tri-plate arrangement.

3. The system is planned to be supported on (moored to) the seabed.

4. The system is planned to be in water deep enough for the floating turbine support structure to be located in a floating condition with the turbine location directly below the hook.

5. The structure supporting the hook may be self-erecting.

6. The components can be brought under the hook using floating transportation -barges or ships.

7. The sea-transportation is planned to be moored such that it can be moved under the hook and then away to a storage location without disconnecting the moorings. The position would be moved by winches adjusting the lengths of mooring lines.

8. The floating structure would similarly be moored and moved under the hook for installation of the wind turbine components.

9. The wind turbine components would be lifted higher than their location on the floating structure, and when the structure is located under the hook the component would be lowered into place on the floating structure.

10. The support structure may be achieved by one of the following methods: a. A tripod structure with pads supporting it on the seabed b. Two piled towers (similar to wind turbine towers) with a beam at the top spanning between the towers with the hook(s) suspended from the beam. The towers may be angled so that the spacing at the base is greater than at the top as the floating structure is wider at the base than at the top.

This reduces the size of beam at the top. The support piles may also be angled so that there is limited bending moment in the towers (axial compressive force).

c. The towers could be lattice structures.

d. The towers could be dismantlable for ease of transportation 11. The system will also be used for installing the blades. This is one of the reasons for the smaller hook.

12. The winches for the hooks would be in the base of the towers above the water line. The power for the winches may be on the towers or from another vessel or power supply.

13. The winches would most likely be multi-fall. It may be two winches with a common wire allowing the work points of the wire to be adjusted to increase its life The winches could be in separate legs.

14. The hooks may have some local later movement.

15. The hooks will have swivels which may be powered.

16. There will be various access platforms which will allow access to the various components as necessary for carrying out the assembly tasks. These may be retractable platforms with the ability to extend, slew and vary in height from their foundation point on the tower.

17. The towers may float when on the sea -there may be fixed tanks in the towers.

18. There will be personnel transport systems (lifts) and equipment transport system inside or outside at least one of the legs.

With regard to embodiments where the structure 10 is a jacket, e.g. for a wind turbine, the reader will note the following.

Sometimes support jackets for offshore wind turbines are made in two halves (upper and lower) and joined together before going offshore. The single point lift could be used for that purpose. In such case, the reader will note: 1 Jackets are attached (moored) to the seabed.

2 The jackets could come to the assembly site in two halves onboard a barge/ship.

3 The floating transport would locate under the lifting point and attach to the upper part of the jacket.

4 The upper part of the jacket would be lifted and suspended higher than the lower part of the jacket.

The floating transport would be moved to bring the lower part of the jacket under the upper part.

6 The upper part would be lowered and landed on the lower part of the jacket.

7. The permanent connection between the upper and lower part would be completed.

This may be of particular benefit in locations having a lot of bridges at the entrances to ports or the like.

In addition to the attributes previously discussed, notable features of the present invention are as follows: * Single point lift, optionally with possible micro movement (500mm).

* Could be from: * gantry (fixed to the seabed), and which may taper towards the top * 3 leg tripod or 4 leg tetrapod, which could have equal leg sizes and so also equal angles or different sized legs/ angles.

* Because the lifting point is static, the build-up of the wind turbine tower (onto a floating foundation) or jacket (onto a barge or similar) is via moving the 'floater' or barge and tower/ jacket components in and out under the single point lift. This could be via winches or vessels (tugs) -winches preferred to keep vessels away from the lifting structure.

* Erection of the tripod/ tetrapod could be through pushing from below/lifting from above the centre tri-plate along with also possibly tightening the connections between the legs.

* Tripod/tetrapod could be assembled at the quayside or on quay and towed to site or towed to site and assembled in parts.

* The tripod/ tetrapod may have buoyancy fitted around the structure (or as part of the structure itself) to assist with erection, e.g., may be part assembled under water.

* Tripod/tetrapod could be mobile and transportable.

* The device/apparatus could be used for construction and/or subsequent maintenance.

* The device/apparatus could be used onshore (though the Inventors expect that the max. benefits will be derived from use offshore in an area with sufficient water depth, sufficiently deep access channel, reasonably sheltered, near a workforce and near marshalling and support port facilities).

It will be appreciated that the embodiments of the present invention hereinbefore described are given by way of example only and are not meant to limit the scope of thereof in any way.

It will be appreciated that in preferred embodiments of the present invention, the structure is a floating/buoyant structure and/or is provided on a floating/buoyant (base) body or foundation.

It will be appreciated that the device/apparatus of embodiments of the present invention allows for: unattended lifting of parts of the structure; landing of parts of the structure without human intervention within the assembly area; no personnel being required to be deployed under the lifting arrangement, in use. Figure 15a depicts a perspective view of a running gear module, according to an embodiment of the disclosure. Figure 15b depicts a line drawing of the running gear module of Figure 15a. The layout in effect has two top assemblies: the top holds the three legs together and supports the running gear module which can be run up and down the structure. In an example, a weight of the running gear may be in the region of 250t, but the load it can generate may be the full capacity of the multi fall hook. In example embodiments, 1000t, 1500t or even greater lift may be provisioned for.

A top assembly 105 is shown.

Also depicted are three legs 110a, 110b, 110c of the erectable structure.

The top assembly 105 holds the three legs 110a, 110b, 110c together and supports a running gear module 115 which can be run up and down the structure.

A first plurality of pin and clevis arrangements 120 are depicted. The pin and clevis arrangements 120 couple the top assembly 105 to the three legs 110a, 110b, 110c Also depicted is a hoist 125 to pull up the running gear module 115. In a non-limiting example, the hoist may have a 300t capacity.

When fully in position, as depicted, a second plurality of pin and clevis arrangements 130 may fix the running gear module 115 to the structure, e.g. to the three legs 110a, 110b, 110c, thereby providing a mechanical connection.

With general reference to the above-described embodiments, and in particular the example embodiments of Figures 15a and 15b: 1. The erection of the tripod (or multi legged structure) may be assisted by a post mounted on a floating structure which is through the central part of the 'tripod'.

The central part of the structure may then be 'walked' up the post with for instance a walking clamp or clamps while simultaneously pulling on tension members between the centre and the base (or towards the base) of the legs or between the bases of the legs. The post may be initially on a floating structure with the top of the multi-leg structure placed around the post (it may be installed in pieces that are then joined together on the deck or it may be lowered over the top of the post.

The floating structure may be lowered to the seabed to provide the reaction to lift the multi-legged structure into position or it may be floating providing there is sufficient buoyancy and stability capacity to react the loads. The post may alternatively be fitted with linear winches at the top to lift the top of the multi-legged structure or may have return sheaves with winches on the deck. The post may have another post inside so that when the top of the multi-legged structure reaches the top of the post then the internal post may be extended to continue with the raising process.

2 The multi leg structure may be erected without any of the lifting machinery in place. It may then be lifted into place following erection of the structure.

3 The structure may have some of it key structural components lifted into place following the initial erection of the structure. These structural components may also form part of the platform for the lifting machinery.

4 The lifting machinery may be able to be lowered and taken away for any reason including but not exclusively servicing, maintenance, repair, preservation.

The windage of the structure may be reduced by removing some of the structure -particularly upper structure -for instance roofs or safe areas for personnel that may only be required during operations.

6 The parts of the structure that are lifted post the initial erection may be used to make the structure stiffer in order to reduce buckling loads.

7 In the case of a tripod it is envisaged that there may be a mud-mat barge at the base of each leg. These barges could be fitted with buoyancy that may extend from their deck and when on the seabed their tops would be above the waterline.

8 This may assist with the sinking of the mud-mat barges into place.

The mud-mat barges may be ballasted so that they provide lateral stability (from say wind and tidal forces) during their operations. This may be achieved by at least one of: a. Pumping in water or other higher density material to provide a gravity anchor (e.g. mud or haematite) b. Sheet piles around the mud-mat barge c. Piled anchors d. Suction anchors e. Dray anchors attached by chain, wire or rope f. Securing lines to the shore.

Although the disclosure has been described in terms of preferred embodiments as set forth above, it should be understood that these embodiments are illustrative only and that the claims are not limited to those embodiments. Those skilled in the art will be able to make modifications and alternatives in view of the disclosure, which are contemplated as falling within the scope of the appended claims. Each feature disclosed or illustrated in the present specification may be incorporated in any embodiments, whether alone or in any appropriate combination with any other feature disclosed or illustrated herein.

Claims

CLAIMS 1 2. 4. 5. 7COAn apparatus for assembling a structure such as an offshore structure, wind turbine or jacket, the apparatus comprising: an erectable structure; and a post or column configured to extend through a central portion of the erectable structure.
The apparatus of claim 1, wherein the post or column is mounted on a floating structure.
The apparatus of claim 1 or 2, wherein the central portion of the erectable structure is configured to be walked up the post or column during a process of erection of the erectable structure.
The apparatus of claim 3, comprising one or more walking clamps for walking the central portion of the erectable structure up the post or column.
The apparatus of claim 3 or 4, wherein the central portion comprises a running gear module configured to be run up and down the post or column.
The apparatus of claim 5, wherein: the post or column comprises one or more winches at an upper or top portion, the one or more winches configured to lift an upper or top portion of the erectable structure; or when dependent upon claim 2, the post or column comprises one or more return sheaves, and winches at, on, or in the general proximity of, a deck of the floating structure.
The apparatus of any preceding claim, wherein the post or column comprises a primary post or column comprising at least one further post or column disposed inside the primary post or column, wherein the primary post or column and the at least one further post or column are arranged in a telescopic arrangement.
8 The apparatus of any preceding claim, wherein the erectable structure comprises a tripod comprising three legs, and further comprising a mud-mat barge at a base portion of each leg.
9 The apparatus of claim 8, comprising: a first plurality of pin and clevis arrangements configured to couple a top assembly to the three legs; and when dependent on claim 5, a second plurality of pin and clevis arrangements configured to fix the running gear module to the three legs.
10. The apparatus of claim 8 or 9, comprising tension members disposed between bases of the legs.
11. The apparatus of any of claims 8 to 10, wherein each mud-mat barge is ballasted by at least one of: Cr) water, mud or haematite; sheet piles disposed around each mud-mat barge; piled anchors; suction anchors; or dry anchors attached by chain, wire or rope securing lines to the shore.
12 The apparatus of any preceding claim, wherein the erectable structure is: expandable or selectively movable from a first or collapsed state to the second expanded or erected state; and collapsible or further selectively movable from the second state to the first state.
13. A method of erecting an erectable structure, the method comprising: providing an erectable structure; and providing a post or column configured to extend through a central portion of the erectable structure; and raising a central portion of the erectable structure relative to the post or column.
14. The method of claim 13, comprising transporting the erectable structure in a collapsed state to a location for assembling an offshore structure and then, when at the location, erecting the erectable structure.
15. The method of claim 13 or 14, wherein the erectable structure is installed in pieces that are joined together on a deck and/or lowered over the top of, and/or assembled around, the post or column.
16. The method of any of claims 13 to 15, wherein erection of the erectable structure comprises walking the central portion of the erectable structure up the post or column using one or more walking clamps.
17. The method of any of claims 13 to 16 wherein, while the central portion of the erectable structure is being raised: a pulling force is applied to tension members between a centre and a Cr) base of legs of the erectable structure; or a pulling force is applied to tension members between bases of legs of the erectable structure.
18. The method of any of claims 13 to 17, wherein providing the post or column comprises providing the post or column on a floating structure with the top of the erectable structure placed around the post or column.
19. The method of claim 18, comprising lowering or extending the floating structure, or at least a portion thereof, to a seabed.
20. The method of any of claims 13 to 20, comprising: fitting a one or more winches to the post or column; configuring the one or more winches to lift an upper or top portion of theerectable structure.
21. The method of any of claims 13 to 20, wherein the post or column comprises a primary post or column comprising at least one further post or column disposed inside the primary post or column, wherein the primary post or column and the at least one further post or column are arranged in a telescopic arrangement, and wherein during assembly of the erectable structure, when an upper portion or top of the erectable structure is raised to reach the top or upper portion of the post or column, then the at least one further post or column may be is telescoped to enable a continuation of raising the upper portion or top of the erectable structure.COC icr c:D