GB2473058A

GB2473058A - Transition piece with conduit located around the pile of an offshore installation

Info

Publication number: GB2473058A
Application number: GB0915112A
Authority: GB
Inventors: Paul Carter
Original assignee: SLP ENGINEERING Ltd; ZEIFER UK III Ltd
Current assignee: ZEIFER UK III LTD
Priority date: 2009-08-29
Filing date: 2009-08-29
Publication date: 2011-03-02
Also published as: GB0915112D0

Abstract

Transition piece 10 to mount a conduit 18 to the pile 12 of an offshore installation at points above 32 and below 34 the mean sea level MSL without the need for divers or a remote operated vehicle. The transition piece 10 is located around the pile 12 of the offshore installation and comprises an extending portion 22 that extends downwardly below sea level MSL. Preferably the offshore installation is a wind turbine comprising a monopole 12, the conduit is one or more j-tubes 18 permanently mounted onshore to the transition piece 10, and the extending portion extends downwardly from an upper portion sleeve 20. The j-tubes may carry electric cables and may extend down to the sea bed 40 and upwardly through a passageway 46 in the pile 12 above the sea level MSL. The transition piece 12 may include an anode ring 50 and may allow adjustment of its vertical orientation relative to the pile 12 using jacks prior to grouting together.

Description

Offshore Installation

FIELD OF THE INVENTION

The present invention relates to apparatus for mounting a conduit to an offshore installation and to a method of mounting a conduit to an offshore installation. In particular, the present invention relates to an improved transition piece for an offshore wind turbine and to a method of mounting a conduit to a transition piece of an offshore wind turbine.

BACKGROUND OF THE INVENTION

Offshore installations generally comprise structures which are supported in the sea bed and extend upwardly to provide a tower rising above mean sea level. Such offshore installations include offshore wind turbines which may include a monopile arrangement such that a single pile extends upwardly from the sea bed and includes a wind turbine at an upper position. The monopile is a tubular structure which generally comprises a steel pile which is driven and/or drilled into the sea bed to a predetermined depth.

Offshore installations such as offshore wind turbines include cables that connect the wind turbine to other wind turbines and to on shore installations and to other facilities. In particular, such cables are used to supply power to and from the wind turbines. In addition, cables may be used to provide communications and/or control signals to and from the wind turbines.

The cables for offshore wind turbines may locate within the monopile and the monopile housing may include an exit hole(s) provided at a lower location at or within the sea bed which enables the cables to emerge from the monopile.

Accordingly, such an arrangement requires the monopile to be provided with a hole at a specific location and these are expensive and require the use of divers and/or a remote operated vehicle together with complex sealing devices.

Alternatively, the cables are provided within a J-tube which is secured to the outside of the monopile. A J-tube is a rigid hollow conduit which includes an upward vertical section and a lower section which travels through a curve to provide a substantially horizontal exit which may locate at or within the seabed.

The attachment of such J-tubes is completed once the monopile has been erected and is in the final position. This subsequent attachment therefore requires the use of divers and/or a remote operated vehicle. The attachment of the J-tubes below mean sea level and, in particular, at or adjacent to the seabed, is, therefore, time consuming and expensive and includes numerous hazards and risks.

Some shallow offshore wind turbines may simply allow cables to dangle unsupported downwards from the monopile but this provides numerous risks and hazards and can not be utilized in deeper water.

It is an aim of the present invention to overcome at least one problem associated with the prior art whether referred to herein or otherwise.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided apparatus for mounting a conduit to an offshore installation comprising a transition piece which is arranged, in use, to locate around a pile of the offshore installation, the transition piece comprising first mounting means to secure an upper part of the conduit above mean sea level, the transition piece further comprising an extending portion which extends downwardly from an upper portion of the transition piece and wherein the extending portion comprises second mounting means in order to secure a lower part of the conduit below mean sea level.

Preferably, the conduit comprises a J-tube.

The conduit may comprise an I-tube.

Preferably, the offshore installation comprises an offshore wind turbine.

Preferably, the offshore installation comprises a monopile.

Preferably, the second mounting means secures the conduit adjacent to the sea bed.

Preferably the first mounting means is provided on the upper portion of the transition piece.

Preferably the first mounting means is integral with the transition piece and more preferably the first mounting means is integral with the transition piece prior to the transition piece being located around the pile.

Preferably the conduit is integral with the transition piece and more preferably the conduit is integral with the transition piece prior to the transition piece being located around the pile.

Preferably the second mounting means is integral with the transition piece and more preferably the second mounting means is integral with the transition piece prior to the transition piece being located around the pile.

The apparatus may comprise third mounting means in order to secure a part of the conduit below mean sea level. The third mounting means may be provided on the upper portion of the transition piece.

The first mounting means and/or the second mounting means and/or the third mounting means may comprise a mounting bracket and preferably comprise a plurality of brackets which are arranged to secure the conduit at spaced apart locations along the length of the conduit.

Preferably the extending portion is arranged, in use, to extend around a part of an outer surface of the pile.

Preferably the extending portion extends around an arcuate section of the pile.

Preferably the extending portion extends around a part of the circumference of the pile.

The extending portion may extend around less than 180 degrees of the circumference of the pile and preferably extends around less than 90 degrees of the circumference of the pile.

The extending portion may comprise a plurality of mounting means to secure the conduit to the transition piece in a plurality of locations below mean sea level.

Preferably the upper portion of the transition piece comprises a sleeve section.

Preferably the sleeve section extends around the complete periphery of the pile, in use.

The transition piece may comprise a passageway to enable the conduit to pass through the transition piece. Preferably, the passageway is arranged, in use, to be located above mean sea level. Preferably the passageway is arranged, in use, to locate above the pile.

Preferably the conduit is arranged, in use, to be mounted to the transition piece prior to the transition piece being located around the monopile.

The transition piece may comprise a plurality of arrays of support means in order to support an array of conduits.

The conduit may comprise an upper linear section and a lower angled section.

Preferably the upper support means is arranged to support and retain the linear section and the second mounting means may be arranged to support and retain the conduit adjacent to the angled section.

Preferably the angled section of the conduit provides a lower entry aperture. The lower portion of the conduit may pass through the angled section and provide a substantially horizontal section, in use, and the conduit may comprise a lower entry aperture which may be substantially vertical, in use.

Preferably the upper end of the conduit locates within the periphery of the transition piece. Preferably the conduit provides an exit aperture for a cable(s) to exit the conduit within the transition piece.

Preferably the transition piece comprises installation securement means in order to secure an installation on the transition piece and for the installation to be secured to the pile. The installation securement means may comprise a securement flange located at an upper end of the transition piece.

Preferably the transition piece is arranged, in use, to be bonded and/or adhered to the pile. In particular, the installation may comprise an adhesive located between the transition piece and the pile.

Preferably the transition piece comprises prefabricated apparatus and equipment.

According to a second aspect of the present invention there is provided a method of mounting a conduit to an offshore installation comprising locating a transition piece around a pile of the offshore installation, the method comprising providing the transition piece with first mounting means to secure an upper part of the conduit above mean sea level, the method further comprising providing the transition piece with an extending portion which extends downwardly from an upper portion of the transition piece and wherein the extending portion comprises second mounting means in order to secure a lower part of the conduit below mean sea level.

Preferably the method comprises securing the conduit to the transition piece prior to locating the transition piece around the pile.

The method may comprise securing the conduit to the transition piece whilst onshore and preferably comprises completely securing the conduit to the transition piece whilst onshore. The method may comprise securing the complete length of the conduit to the transition piece whilst onshore.

The method may comprise locating the transition piece around the pile whilst offshore.

The method may comprise welding the conduit to the transition piece.

The method may comprise forming an integral transition piece and conduit and preferably comprises forming an integral transition piece and conduit whilst onshore.

BRIEF DESCRIPTION OF THE DRAWINGS

The preferred embodiment of the present invention will now be described by way of example only, with reference to the drawings that follow in which: Figure 1 is a view of a preferred embodiment of a transition piece mounted to a monopile of an offshore wind turbine; Figure 2 is a front view of a preferred embodiment of a transition piece mounted to a monopile of an offshore wind turbine; Figure 3 is a partially cut away side view of a preferred embodiment of a transition piece mounted to a monopile of an offshore wind turbine; Figure 4 is a partially cut away view of a preferred embodiment of a transition piece mounted to a monopile of an offshore wind turbine; Figure 5 is a schematic partial view of a preferred embodiment of a transition piece mounted to a monopile of an offshore wind turbine; Figure 6 is a side view of a preferred embodiment of a lower securement means retaining a J-tube to a transition piece; and Figure 7 is a plan view of a preferred embodiment of a lower securement means retaining a J-tube to a transition piece.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides a transition piece 10 for a monopile 12 of an offshore wind turbine, as shown in Figures 1 to 5.

As in conventional offshore wind turbines, the monopile 12 is arranged to extend downwardly into the sea bed 14. The monopile 12 generally comprises a cylindrical metal tube section which extends upwardly from the sea bed 14 to a position located above the mean sea level 16. The transition piece 10 comprises an upper section in the form of a sleeve 20 and a lower section in the form of an extending section 22. The sleeve 20 forms a complete circle and is dimensioned to extend around the outer surface of the monopile 12.

A transition piece 10 is generally used in such offshore structure to provide a vertical securement surface. For example, the monopile 12 may not be vertical once driven/drilled into the sea bed 14 and, therefore, the transition piece 10 provides an adjustable portion which can be mounted vertically on the monopile 12. In prior art assemblies, the transition piece 10 may be made as short as possible for cost and material purposes/reasons.

In order to mount the transition piece 10 to the monopile 12, the transition piece and in specifically the sleeve 20, is lifted over the monopile 12 and moved into position along the monopile 12. The transition piece 10 includes retainers which engage the upper end of the monopile 12 and mount the transition piece 10 to the 5. monopile 12. This secures the transition piece 10 relative to the monopile 12.

The transition piece also comprises adjustment means in the form of jacks 24 which can be used to adjust the vertical orientation of the transition piece 10 relative to the monopile 12. For example, the monopile may not be strictly vertical once drilled/driven into the sea bed 14 and these jacks 24 therefore enable the transition piece 10 to be adjusted such that the securement flange 26 provides an even securement surface and, in particular, a horizontal planar securement surface.

The installation procedure may also comprise providing an adhesive, for example a grout, between an inner surface of the transition piece 10 and the outer surface of the monopile 12. In particular, the transition piece 10 is arranged in use to be retained to the monopile 12 solely be the grout.

The transition piece 10 comprise installation securement means in the form of a securement flange 26 located at the upper end thereof. The securement flange 26 enables the main tower of the wind turbine structure to be secured thereto.

The transition piece 10 is prefabricated prior to placing over the monopile 12 and may include prefabricated auxiliary apparatus and installations. For example, the transition piece 10 may be provided with external ladders, platforms, access apparatus as well as internal apparatus. In particular, the transition piece 10 may have internal floors and interconnecting ladders preinstalled prior to the transition piece 10 being secured to the monopile 12. The prefabrication of such apparatus and equipment is highly beneficial in terms of both time and cost. The transition piece 10 also comprises anodes 50 located around the radial periphery below the mean sea level.

Offshore wind turbines require cables in order for the power generated by the wind turbine to be transmitted on shore for use. In addition, offshore wind turbines may require further cables which may connect the offshore wind turbines to other offshore wind turbines or to a control centre. Accordingly, there is a requirement for cables to be connected to the operational area of the offshore wind turbine.

Generally, such cables are located below and within the sea bed in order to protect the cables, for example, this prevents the cables being damaged by trawlers and protects the cables from wear.

The cables for such offshore installations may pass through the J-tubes 18 secured to the installations. The present invention provides complete J-tube securement means which secures the J-tube 18 to the monopile 12 without the need for divers or a remote operated vehicle. However, it is appreciated that other conduits could also be mounted to the monopile 12 using the present invention and, in particular, I-tubes could be readily retained. In particular, the present invention does not require divers or a remote operated vehicle to secure the J-tubes 18 at the lower end adjacent to or within the sea bed 14. In order to achieve this, the present invention provides a transition piece extension 22 which extends downwardly from a sleeve section 20 of a transition piece 10. This extended portion 22 is arranged to correspond with the periphery of the monopile 12 and extends downwardly to a position just above the sea bed 14.

The extended portion 22 comprises an arcuate or a curved section which does not extend around the complete periphery of the monopile 12. The extended portion 22 is arranged to correspond with the outer surface of the monopile 12 and may be directly adhered thereto by grout. As shown in Figures 1 to 5, the extended portion 22 extends in the longitudinal direction of the monopile 12 and is integral with a sleeve section 20 of the transition piece. In particular, the extended portion 22 and the sleeve section 20 is a single piece construction.

The transition piece 10 comprises a plurality of securement means 30 in order to secure the or each J-tube 18 to the outside of the transition piece 10 along the length of the or each J-tube 18. In particular, the securement means provide a complete securement system for securing the J-tube(s) 18 to an offshore wind turbine without the need for divers or operated vehicles.

The transition piece 10 including the J-tube(s) 18 and J-tube securement means is prefabricated and is completed onshore prior to installation. Accordingly, with the present invention, the transition piece 10 is simply located over the monopile 12 and is then secured in position on the monopile 12 with a conventional system. This thereby automatically provides the J-tube(s) 18 on the outside of the monopile 12 and does not require any further fixation.

In the prior art assemblies, the transition piece is a complete section of a sleeve which does not have any downwardly projecting extending portions as in the present invention. Accordingly, in the prior art, the J-tube requires fixing whilst submerged to the monopile at a lower position. The present invention thereby provides a prefixed J-tube which is pie-secured to the transition piece via the extending portion.

The securement means 30 comprises at least an upper securement means 32 and a lower securement means 34. In the preferred embodiment of the present invention, the securement means also comprises an intermediary securement means 36.

As shown in Figure 6 and Figure 7, the securement means comprises a bracket which fixes the J-tube 18 to the transition piece 10. The bracket comprises a welded bracket. The bracket comprises a spacer portion 50 which extend outwardly from a fixation flange 52. At the other end of the spacer portion 50, the bracket is welded to the J-tube 18. In the preferred embodiment, the spacer portion 50 is welded to or integral with a short section 54 of the J-tube 18. This short section 54 provides upper and lower securement flanges 56 which enable securement flanges 58 of further sections of J-tube 18 to be secured thereto. In -11 -the preferred embodiment, all of the securement means 32, 34, 36 comprise identical brackets which are spaced along the length of the J-tube 18 and effectively provide a J-tube 18 which is integral with the transition piece 10.

The upper securement means 32 comprises at least one bracket which is secured to the transition piece 10 and is arranged to retain the J-tube 18 to the sleeve section 20 of the transition piece 10 at a location above mean sea level 16.

Specifically, the upper securement means 32 retains the linear section 42 of the J-tube located above water to the transition piece 10. The J-tube may be arranged to extend through a passageway 46 and into the transition piece 10 just above the upper securement means 32. This passageway is therefore above the water level and can be constructed onshore which is highly beneficial. In addition, the passageway 46 is located at a position above the upper end of the monopile 12 which means that the monopile 12 does not have to be cut which can be time consuming and expensive and may alter the integrity of the monopile 12.

The lower securement means 34 comprises at least one bracket which is secured to the transition piece 10 and is arranged to retain the J-tube 18 to the extending portion 22 of the transition piece 10 at a location below mean sea level 16. In particular, the lower securement means 34 is arranged to secure the J-tube 18 at or adjacent to the angled (curved) section 40 of the J-tube 18 which is generally at or adjacent to the sea bed 14. This prefabricated lower securement bracket 34 means that the J-tube 18 does not need to be fixed at the lower end after the transition piece 10 is mounted to the monopite 12. This negates the fixation of the lower part of the J-tube 18 whilst located underwater. In the preferred embodiment, the transition piece comprises three lower securement brackets 34.

The intermediary securement means 36 comprises at least one bracket which is secured to the transition piece 10 and is arranged to retain the J-tube to the sleeve portion 20 of the transition piece at a location below mean sea level 16. In particular, the intermediary securement means 36 is arranged to secure the linear section 42 of the J-tube 18 below mean sea level 16. -12-

The present invention is illustrated in Figure 1 to Figure 5 in an offshore wind turbine foundation having two J-tubes 18. Accordingly, the securement means 32, 34, 36 and associated brackets can be seen in pairs spaced vertically along the outer periphery of the transition piece until the J-tubes 18 pass through corresponding passageways 46.

As shown in Figure 1 to Figure 5, the transition piece 10 is provided with a passageway 46 which enables the J-tube 18 to pass from the outside of the transition piece 10 to within the transition piece 10 at a location above the monopile 12 and also at a position above mean sea level 16. Again, this passageway 46 and the location of the J-tube 18 through the passageway 46 is completed onshore and, therefore, does not require a time consuming and expensive operation whilst being install on site (i.e. offshore).

The transition piece 10 sits on top of the monopile 12 and also carries a number of appurtenances such as fenders, boat landings, doors and platforms. The transition piece 10 is a cylindrical structure of uniform thickness extending from the base of the turbine tower to below the water line at the lowest astronomical tide.

The transition piece 10 provides a system of J-tubes 18 to support the electrical cables which is fixed and integrated and provides fully supported J-tubes 18 fabricated to the outside of the transition piece 10 and extending to the sea bed 14.

The present invention provides a safe and cost effective solution for the connection of individual offshore wind turbines to the interarray cable network.

The electrical cabling is brought to the turbine within the J-tubes 18 which are integral to the foundation structure. A main feature of the present invention is the extending transition piece 10 which carries the fixed J-tubes 18 on the outside of the foundation from the sea bed 14 to the point at which they are brought inside the transition piece 10 and where the cables can be connected to the turbine electrical system. Since the J-tube 18 and the cables are always external of the monopile 12, this provides a significant cost saving and avoids expensive activities such as the requirement to cut the holes in the monopile 12 and also avoids diver or remote operated vehicle intervention and complex sealing devices.

The present invention provides a simple and robust design which can be installed without the above problems and can be fabricated, assembled, prepared and coated at the onshore fabrication facility prior to delivery offshore as a single integrated structure.

The present invention provides complete cable protection from inside the transition piece 10 all the way to the sea bed 14. Since the J-tube 18 is one continuous tube, the top end of which is easily accessible from the inside of the transition piece 10, providing an air tight seal around the cable is easily achieved. Once sealed at the top, and with the lower open end at the sea bed level, water exchange in the J-tube 18 will be negligible, and any sea water and air inside the J-tube 18 quickly becomes depleted of oxygen thereby reducing the likelihood of internal corrosion without the use of chemicals or expensive internal coatings.

Since the J-tube 18 is an integral part of the transitional piece assembly, the anodes 50 welded to the main body of the transition piece 10 will provide full corrosion protection without the need for underwater earthing straps or connections normally needed between the separate components.

Since the transition piece 10 and J-tubes 18 are fully integrated, the installation can be achieved in a single simple lift. Once located over the pile 12 and lowered so that the normal levelling procedures and grouting can be accomplished. The present invention does not require any installation aids or separate items.

Since the present invention incorporates a continuous J-tube 18 into the design, the cable pulling messenger wires can be preinstalled onshore and the vertical alignment offshore of separate J-tube parts is unnecessary. As the cable is held outside the monopile 12 there is no requirement to provide sealing plugs normally needed when the cable passes through the pile 12 and up into the transition piece -14 -floor. By avoiding penetration in either the transition piece floor or the monopile 12, any entrapped water in the pile 12 will quickly become oxygen depleted and the internal corrosion of the monopile will be reduced. Earth straps to connect the monopile 12 to the transition piece 10 to allow the cathodic protection of the monopile 12 from the anodes 50 on the transition piece 10 are located at an easily accessible point inside the dry space of the transition piece.

The dimensions of the transition piece 10 are arranged to correspond with the particular installation. For example, the radius of the sleeve portion 20 and the angle of curvature for the extending section 22 will depend on the radius of the monopile. In addition, the longitudinal length of the extending portion 22 will relate to the height of the monopile 12 once secured in the sea bed 14. The present invention can therefore be adapted for use in all suitable offshore locations and with all suitable installations. -15-

Claims

CLAIMS1. Apparatus for mounting a conduit to an offshore installation comprising a transition piece which is arranged, in use, to locate around a pile of the offshore installation, the transition piece comprising first mounting means to secure an upper part of the conduit above mean sea level, the transition piece further comprising an extending portion which extends downwardly from an upper portion of the transition piece and wherein the extending portion comprises second mounting means in order to secure a lower part of the conduit below mean sea level.
2. Apparatus according to Claim I in which the conduit comprises a J-tube or an I-tube.
3. Apparatus according to Claim I or Claim 2 in which the offshore installation comprises an offshore wind turbine.
4. Apparatus according to any preceding claim in which the offshore installation comprises a monopile.
5. Apparatus according to any preceding claim in which the second mounting means secures the conduit adjacent to the sea bed.
6. Apparatus according to any preceding claim in which the first mounting means is provided on the upper portion of the transition piece.
7. Apparatus according to any preceding claim in which the first mounting means is integral with the transition piece.
8. Apparatus according to Claim 7 in which the first mounting means is integral with the transition piece prior to the transition piece being located around -16-the pile.
9. Apparatus according to any preceding claim in which the conduit is integral with the transition piece.
10. Apparatus according to Claim 9 in which the conduit is integral with the transition piece prior to the transition piece being located around the pile.
11. Apparatus according to any preceding claim in which the second mounting means is integral with the transition piece.
12. Apparatus according to any preceding claim in which the second mounting means is integral with the transition piece prior to the transition piece being located around the pile.
13. Apparatus according to any preceding claim in which the apparatus comprises third mounting means in order to secure a part of the conduit below mean sea level.
14. Apparatus according to any preceding claim in which the third mounting means is provided on the upper portion of the transition piece.
15. Apparatus according to any preceding claim in which the first mounting means and/or the second mounting means and/or the third mounting means comprises a plurality of brackets which are arranged to secure the conduit at spaced apart locations along the length of the conduit.
16. Apparatus according to any preceding claim in which the extending portion is arranged, in use, to extend around a part of an outer surface of the pile.
17. Apparatus according to any preceding claim in which the extending portion extends around an arcuate section of the pile.
18. Apparatus according to any preceding claim in which the extending portion extends around a part of the circumference of the pile.
19. Apparatus according to any preceding claim in which the extending portion comprises a plurality of mounting means to secure the conduit to the transition piece in a plurality of locations below mean sea level.
20. Apparatus according to any preceding claim in which the upper portion of the transition piece comprises a sleeve section.
21. Apparatus according to Claim 20 in which the sleeve section extends around the complete periphery of the pile, in use.
22. Apparatus according to any preceding claim in which the transition piece comprises a passageway to enable the conduit to pass through the transition piece.
23. Apparatus according to Claim 22 in which the passageway is arranged, in use, to be located above mean sea level.
24. Apparatus according to Claim 23 in which the passageway is arranged, in use, to locate above the pile.
25. Apparatus according to any preceding claim in which the conduit is arranged, in use, to be mounted to the transition piece prior to the transition piece being located around the monopile.
26. Apparatus according to any preceding claim in which the transition piece comprises a plurality of arrays of support means in order to support an array of conduits.
27. Apparatus according to any preceding claim in which the conduit comprises an upper linear section and a lower angled section.
28. Apparatus according to Claim 27 in which the upper support means is arranged to support and retain the linear section and the second mounting means is be arranged to support and retain the conduit adjacent to the angled section.
29. Apparatus according to any preceding claim in which the transition piece is arranged, in use, to be bonded and/or adhered to the pile.
30. Apparatus according to any preceding claim in which the transition piece comprises prefabricated apparatus and equipment.
31. A method of mounting a conduit to an offshore installation comprising locating a transition piece around a pile of the offshore installation, the method comprising providing the transition piece with first mounting means to secure an upper part of the conduit above mean sea level, the method further comprising providing the transition piece with an extending portion which extends downwardly from an upper portion of the transition piece and wherein the extending portion comprises second mounting means in order to secure a lower part of the conduit below mean sea level.
32. A method of mounting a conduit to an offshore installation according to Claim 31 in which the method comprises securing the conduit to the transition piece prior to locating the transition piece around the pile.
33. A method of mounting a conduit to an offshore installation according to Claim 31 or Claim 32 in which the method comprises securing the conduit to the transition piece whilst onshore.
34. A method of mounting a conduit to an offshore installation according to Claim 33 in which the method comprises completely securing the conduit to the transition piece whilst onshore.
35. A method of mounting a conduit to an offshore installation according to Claim 34 in which the method comprises securing the complete length of the conduit to the transition piece whilst onshore.
36. A method of mounting a conduit to an offshore installation according to any one of Claim 31 to Claim 35 in which the method comprises locating the transition piece around the pile whilst offshore.
37. A method of mounting a conduit to an offshore installation according to any one of Claim 31 to Claim 36 in which the method comprise welding the conduit to the transition piece.
38. A method of mounting a conduit to an offshore installation according to any one of Claim 31 to C'aim 37 in which the method comprises forming an integral transition piece and conduit.
39. A method of mounting a conduit to an offshore installation according to Claim 38 in which the method comprises forming an integral transition piece and conduit whilst onshore.
40. Apparatus for mounting a conduit to an offshore installation substantially as herein described with reference to, and as shown in, any of the accompanying drawings.
41. A method of mounting a conduit to an offshore installation substantially as herein described with reference to, and as shown in, any of the accompanying drawings.