Retractable sheave assembly for a hauling system of a spread moored f(p)so platform

Abstract

An adjustable sheave assembly for a hauling system of a spread moored F(P)SO platform comprising: a carrier structure slidably supportable on a sheave trolley of the spread moored F(P)SO platform; a housing supported on the carrier structure; the housing respectively supporting a horizontal sheave and a vertical sheave, the sheaves routing a main rope of the hauling system used to pull in / out operational equipment hung from the F(P)SO platform; wherein the sheave trolley is displaceable in a longitudinal direction along a riser pull in balcony, and the carrier structure is displaceable on the sheave trolley in a transverse direction; and the housing is rotatably supported on the carrier structure such that the vertical sheave is rotatably displaceable to different rotational positions about a vertical rotational axis of the horizontal sheave to thereby align the vertical sheave with an azimuth angle of an equipment slot of the operational equipment.

Description

RETRACTABLE SHEAVE ASSEMBLY FOR AHAULING SYSTEM OF A SPREAD MOORED F(P)SO PLATFORMFIELD

[0001] The present invention generally relates to hauling systems used in Floating Production, Storage and Offloading (FPSO), and Floating Storage and Offloading (FSO) platforms, and particular to a retractable sheave assembly for a hauling system of a spread moored F(P)SO platform.BACKGROUND

[0002] The following discussion of the background to the invention is intended to facilitate an understanding of the present invention only. It should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was published, known or part of the common general knowledge of the person skilled in the art in any jurisdiction as at the priority date of the invention.

[0003] FSPO / FSO platforms provides the technology required for the production, storage and export of hydrocarbon products in remote or deepwater regions. There are two main methods of mooring such platforms respectively known as ‘spread moored’ and ‘turret moored’ F(P)SO platforms. Spread moored F(P)SO platforms are typically in the form of a converted tanker or new-build hull supporting a storage vessel and the facilities required for the production of hydrocarbon products. Risers that bring the hydrocarbon product to and from the F(P)SO platform are hung off the side of the platform. Such spread moored F(P)SO platforms generally require hauling systems to enable the operational equipment hung from the platform such as Steel Catenary Risers (SCR), flexible risers, and umbilicals to be pulled in or out from adjacent the support vessel.

[0004] SCRs are rigid components that hang from the F(P)SO platform at a specific angle from that platform. That remains unchanged before and after pull in of the SCR, requiring that the SCR is retained at that angle during pull up. The riser head of the SCR therefore needs to be received within a specific riser headreceptacle mounted on the side shell of the F(P)SO platform after pull up. These riser head receptacles respectively provide ‘SCR slots’ for each SCR to be retained when pulled up. Flexible risers and umbilicals are by comparison relatively soft and flexible and do not hang at any specific angle from the F(P)SO platform. Each flexible riser / umbilical can therefore be more readily pulled in through a bell mouth mounted on the side shell of the platform and retained in place by an ‘l-tube’ that may be mounted on an upper riser balcony of the platform. Each bell mouth provides a respective ‘flexible riser slot’ or ‘umbilical slot’ from which the flexible riser / umbilical is retained after pull in.

[0005] Current hauling systems used on such spread moored F(P)SO platforms typically require the use of fixed or pivotable turndown, inboard and outboard riser balcony sheaves to enable the main rope of the hauling system to be better aligned with the operational equipment being pulled in / out. Such hauling systems require a complex system of sheaves to enable the main rope of the hauling system to be positioned so as to be correctly aligned with that equipment. These known hauling systems are however difficult to always align correctly, as well as being difficult to operate and maintain and generally require a number of personnel to operate the system.

[0006] An object of the invention is to ameliorate one or more of the above- mentioned difficulties.SUMMARY

[0007] According to an aspect of the present disclosure, there is provided an adjustable sheave assembly for a hauling system of a spread moored F(P)SO platform comprising: a carrier structure slidably supportable on a sheave trolley of the spread moored F(P)SO platform; a housing supported on the carrier structure; the housing respectively supporting a horizontal sheave rotatable about a generally vertical rotational axis, and a vertical sheave supported adjacent the horizontal sheave and rotatable about a generallyhorizontal rotational axis, the horizontal and vertical sheaves routing a main rope of the hauling system used to pull in / out operational equipment hung from the F(P)SO platform; wherein the carrier structure is supportable on a sheave trolley which is displaceable in a longitudinal direction along a riser pull in balcony of the F(P)SO platform, and the carrier structure is displaceable on the sheave trolley in a transverse direction relative to the longitudinal direction; and wherein the housing is rotatably supported on the carrier structure such that the vertical sheave is rotatably displaceable to different rotational positions about the vertical rotational axis of the horizontal sheave to thereby align the vertical sheave with an azimuth angle of an equipment slot of the operational equipment.

[0008] In some embodiments, the operational equipment comprises a Steel Catenary Riser (SCR), and the equipment slot comprises a SCR riser head receptacle for the SCR mounted on the F(P)SO platform.

[0009] In some embodiments, the operational equipment comprises a flexible riser or umbilical, and the equipment slot comprises a bell mouth mounted on the F(P)SO platform.

[0010] In some embodiments, the vertical sheave is rotatably mounted on a side bracket extending from the housing.

[0011] In some embodiments, the adjustable sheave assembly further comprises a rotation mechanism for controlling rotation of the housing.

[0012] In some embodiments, the rotation mechanism comprises a hydraulic cylinder interconnected to a locking gripper for interacting with rotation skidding pin holes provided on the housing.

[0013] In some embodiments, the adjustable sheave assembly further comprises a rotation-locking mechanism for lock the housing at a required angle on the carrier structure.

[0014] In some embodiments, the rotation-locking mechanism comprises one or more locking pins for engaging rotation-locking pin holes provided within the housing.

[0015] In some embodiments, the adjustable sheave assembly further comprises an actuating mechanism for controlling the displacement of the carrier structure in the transverse direction on the sheave trolley.

[0016] In some embodiments, the actuating mechanism comprises one or more hydraulic cylinders.

[0017] In some embodiments, the adjustable sheave assembly further comprises a transverse locking mechanism for locking in position the carrier structure on the sheave trolley.

[0018] In some embodiments, the transverse locking mechanism comprises at least one transverse locking pin for engaging transverse-locking pin holes provided on the sheave trolley.

[0019] In some embodiments, the adjustable sheave assembly further comprises at least one carrier structure hold-down clamp fixed to the sheave trolley for retaining the carrier structure thereon.

[0020] According to another aspect of the present disclosure, there is provided a hauling system for a spread moored F(P)SO platform comprising an adjustable sheave assembly as described above.

[0021] According to a further aspect of the present disclosure, there is provided a method of pulling in or out operational equipment hung from a F(P)SO platform using a hauling system having an adjustable sheave assembly as described above, comprising: a) if necessary, displacing the carrier structure on the sheave trolley in a transverse direction relative to the longitudinal direction of the riser pull in balcony; and b) rotating the housing on the carrier structure such that the vertical sheave isrotatably displaceable to thereby align the vertical sheave with an azimuth angle of the operational equipment.

[0022] Other aspects and features will become apparent to those of ordinary skill in the art upon review of the following description of specific embodiments in conjunction with the accompanying figures.BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In the figures, which illustrate, by way of example only, embodiments of the present invention,

[0024] [Figure 1 ] is a side schematic view of a prior art hauling system for a spread moored F(P)SO platform shown being used to pull up a Steel Catenary Riser (SCR) without keel-hauling;

[0025] [Figure 2] is a side schematic view of another prior art hauling system for a spread moored F(P)SO platform shown being used to pull up a Steel Catenary Riser (SCR) without keel-hauling;

[0026] [Figure 3] is a side schematic view of the hauling system of [fig. 1 ] shown being used during the pull up of a Steel Catenary Riser (SCR) with keel-hauling;

[0027] [Figure 4] is a side schematic view of the prior art hauling system of [fig. 1 ] shown being used to pull up a flexible riser or an umbilical;

[0028] [Figure 5] is a plan view of a hauling system for a spread moored F(P)SO platform according to the present disclosure;

[0029] [Figure 6] is a detailed isometric view of a retractable sheave assembly of the hauling system of [fig. 5] shown in a fully retracted position;

[0030] [Figure 7] is a detailed isometric view of a retractable sheave assembly of the hauling system of [fig. 5] shown in a fully extended position;

[0031] [Figure 8] is a side schematic view of the hauling system of [fig. 5] shown being used to pull up a Steel Catenary Riser (SCR) without keel-hauling;

[0032] [Figure 9] is a side schematic view of the hauling system of [fig. 5] shown being used to pull up a Steel Catenary Riser (SCR) with keel-hauling; and

[0033] [Figure 10] is a side schematic view of the hauling system of [fig. 5] shown being used to pull up a flexible riser or umbilical.

[0034] Other arrangements of the invention are possible and, consequently, the accompanying drawings are not to be understood as superseding the generality of the preceding description of the invention.DETAILED DESCRIPTION

[0035] Throughout this document, unless otherwise indicated to the contrary, the terms “comprising”, “consisting of”, “having” and the like, are to be construed as non- exhaustive, or in other words, as meaning “including, but not limited to”.

[0036] Furthermore, throughout the specification, unless the context requires otherwise, the word “include” or variations such as “includes” or “including” will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

[0037] Furthermore, throughout the specification, unless the context requires otherwise, the word, ‘equipment slot’ is used to refer to the location of an SCR riser head receptacle in the case of an SCR for receiving an SCR riser, or the location of a bell mouth and i-tube for receiving a flexible riser or umbilical.

[0038] Furthermore, throughout the specification, unless the context requires otherwise, the word, ‘azimuth angle’ is used to refer to the location of an equipment slot of operational equipment relative to the hauling system.

[0039] Example embodiments of the present invention will now be described with reference to the accompanying drawings. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention. Other definitions for selected terms used herein may be found within the detailed description of the invention and apply throughout the description. Additionally, unless defined otherwise, all technical and scientific termsused herein have the same meanings as commonly understood by one or ordinary skill in the art to which this invention belongs. Where possible, the same reference numerals are used throughout the figures for clarity and consistency.

[0040] [Figs. 1 to 4] show prior art hauling systems 10,20 used for pulling in and out of operational equipment such as Steel Catenary Risers (SCR), flexible risers and umbilicals of a spread moored F(P)SO platform. In the situation where it is required to pull in a SCR without keel-hauling, this is normally achieved by the method shown in [Fig. 1 or 2], The prior art hauling system 10 includes a fixed turndown sheave 31 1 as shown in [fig. 1] or a pivotable turndown sheave 312 as shown in [fig. 2], respectively supported on a longitudinally skiddable sheave trolley 310. The sheave trolley 310 is supported on a riser pull in balcony 300 of the F(P)SO platform extending outboard from the side shell 100 of the F(P)SO platform, and is displaceable in a longitudinal direction along the riser pull in balcony 300. A main rope 301 is normally routed by the fixed turndown sheave 31 1 or the pivotable turndown sheave 312 so that the main rope 301 can be generally aligned to the relevant SCR slot longitudinally before the main rope 301 can be connected to the riser head 1 11 of the SCR.

[0041] In the pull in / out method without keel-hauling shown in [Fig 1 ], the main rope 301 is routed through the fixed turndown sheave 31 1 before being routed through two other sheaves, namely the inboard riser balcony sheave 210 and the outboard riser balcony sheave 220. These inboard and outboard balcony sheaves 210,220 are respectively located on a lower riser balcony 200 which is positioned below the riser pull in balcony 300, and also extends outboard from the side shell 100 of the F(P)SO platform. This arrangement is utilised to create enough clearance between a riser head receptacle 1 10 provided on the side shell 100, and a riser head 1 1 1 of the SCR being pulled up by the hauling system 10 during the pull up operation of the SCR. After the riser head 1 1 1 is pulled up high enough so that there is a sufficient clearance provided between the riser head 1 1 1 and the riser head receptacle 1 10, an auxiliary line 121 , which is routed using an auxiliary side shell sheave 120 mounted on side shell 100, can then be used to pull the riser head 11 1in an inboard direction so that it can be lowered down and received by the riser head receptacle 1 10.

[0042] In the pull in / out method without keel-hauling shown in Fig 2, the hauling system is provided with a pivotable turndown sheave 312 instead of the fixed turndown sheave 311 shown in [fig. 1 ], and the main rope 301 is routed by the pivotable turndown sheave 312, and can be connected directly to the riser head 1 1 1 . The maximum pivot angle of the pivotable turndown sheave 312 is the angle of the SCR relative to the side shell 100 of the F(P)SO platform. However, the maximum pivot angle is normally insufficient to create enough clearance between a riser head receptacle 110 provided on the side shell 100, and a riser head 1 11 of the SCR being pulled up by the hauling system 20 during the pull up operation of the SCR. The F(P)SO platform therefore has to perform ‘ballasting’ so that the hull can roll about 1 ° -1.5° towards the SCR pull in direction in order to create sufficient clearance between the riser head receptacle 1 10 and the riser head 1 1 1.

[0043] In the situation where it is required to pull in a SCR with keel-hauling, this is typically achieved by the pull in / out method shown being used in [Fig 3]. The configuration of the hauling system 10 shown in [fig. 3] is the same as that shown in [Fig 1], The same inboard riser balcony sheave 210 and outboard riser balcony sheave 220 arrangement is required on lower riser balcony 200 to create enough clearance between the riser head receptacle 110 and riser head 1 1 1 being pulled up. However, the outboard riser balcony sheave 220 may need to be located further outboard to allow for better clearance between the riser head receptacle 1 10 and riser head 1 11 due to the angle of the SCR line.

[0044] [Fig. 4] shows the pull in / out method used to pull in flexible risers and umbilicals, which differs from the pull in method of SCRs. This is typically achieved using the same hauling system 20 as shown in [Fig. 1 or 2], The main rope 301 is routed by the fixed or pivotable turndown sheave 31 1 ,312 mounted on the longitudinally skiddable sheave trolley 310 supported on the riser pull in balcony 300. This enables the main rope 301 to be generally aligned to the relevant I tube 201 (located on the lower riser balcony 200) center above a respective flexible riser slot or umbilical slot longitudinally before the main rope 301 is paid out for the supportvessel to pick up and then connect to the pull in head (not shown) of the flexible riser or umbilical. The pull in head of flexible riser or umbilical is directly pulled up through a bell mouth 130 via a bending stiffener (not shown) mounted on the side shell 100 and locked above the top of an l-tube 201 located on the lower riser balcony 200. The bell mouth 130 respectively provides the flexible riser slot for the flexible riser, or the umbilical slot for the umbilical.

[0045] A spread moored F(P)SO platform operating in deep water (2000m or more) needs a hauling system 10,20 with the combination of equipment required to achieve the pull in / out methods shown in [Figs. 1 to 4], It is therefore necessary to have an inboard riser balcony sheave 210 and outboard riser balcony sheave 220 to achieve these methods. It is however difficult to relocate the inboard and outboard sheaves 210,220 to better align them at respective SCR slots for different SCR pull ins because there is always limited space on the lower riser balcony 200 to accommodate them at different positions on the lower riser balcony 200.

[0046] The hauling system 30 according to the present disclosure therefore seeks to eliminate the need to use any Inboard riser balcony sheave 210 and outboard riser balcony sheave 220 when used in different riser pull in I out scenarios. [Figs. 5 to 10] show a hauling system 30 for a F(P)SO platform according to the present disclosure. [Fig. 5] shows a plan view of the riser pull in balcony 300. The auxiliary lines 121 from auxiliary winches 330A and 330B are routed using auxiliary sheaves (not shown) on the sheave trolley 310 down to the auxiliary side shell sheaves 120 on side shell 100. The main rope 301 from a main winch 320 is routed by a retractable sheave assembly 001 according to the present disclosure mounted on the sheave trolley 310. The retractable sheave assembly 001 is able to extend and retract in a transverse direction (i.e., in an inboard or outboard direction) on the sheave trolley 310. Furthermore, the same retractable sheave assembly 001 can also rotate clockwise or anticlockwise to correctly align the vertical sheave 003 with different respective azimuth angles of the SCR slots, or to align the vertical sheave 003 to the centre of the l-tube 201 inboard in the case of flexible risers or umbilicals pull. As the sheave trolley 310 can skid longitudinally along the riser pull in balcony 300, the retractablesheave assembly 001 can reach all the riser slots (for the SCRs with or without Keelhauling, and the flexible risers and umbilicals) along the riser pull in balcony 300.

[0047] [Figs. 6 and 7] show in more detail the adjustable sheave assembly 001 according to the present disclosure, with [fig. 6] showing the adjustable sheave assembly 001 in a fully retracted position, and [fig. 7] showing the adjustable sheave assembly 001 in a fully extended position. The adjustable sheave assembly 001 has a housing 008 supported on a carrier structure 010; the housing 008 respectively supporting a horizontal sheave 002 rotatable about a generally vertical rotational axis, and a vertical sheave 003 supported on a side bracket 009 extending from the housing 008, and adjacent the horizontal sheave and rotatable about a generally horizontal rotational axis. The horizontal and vertical sheaves 002,003 are used to route the main rope 301 from the main winch 320 to respective riser slots / riser head. The retractable sheave assembly 001 is rotatably held down by a sheave assembly hold down mechanism 011 which is fixed on a carrier structure 010. The carrier structure 010 is transversely slidably mounted on the sheave trolley 310 and it is held down by a carrier structure hold down clamp(s) 31 1 , which is(are) fixed on the sheave trolley 310. The transverse sliding is achieved by an actuating mechanism 016. [Fig. 7] shows a possible embodiment of the actuating mechanism 016 in the form of a hydraulic cylinder. The carrier structure 010 can be locked at any position within its range of extension by one or multiple numbers of transverse locking mechanism 013. For example, one possible embodiment of the transverse locking mechanism can be in the form of transverse-locking pin / pins with transverse locking pin holes 015 as shown in [Fig 7],

[0048] As the retractable sheave assembly 001 is rotatably held down by sheave assembly hold down mechanism 01 1 , its rotation can be controlled by a rotation mechanism 012. A possible embodiment of the rotation mechanism 012 is as a hydraulic cylinder 012A with a locking gripper 012B interacting with rotation skidding pin holes 005 provided on the housing 008. The vertical sheave 003 on the retractable sheave assembly 001 can be rotated clockwise or anticlockwise about the pivotal axis at the centre of the horizontal sheave 002 by the rotation mechanism 012. One or more rotation-locking mechanisms 014 can be used to lock the verticalsheave 003 at any required angle for riser pull in I out operation. One possible embodiment of the rotation-locking mechanism is as locking pin / pins with rotationlocking pin holes 004 as shown in [Fig. 6].

[0049] [Figs. 8 to 10] respectively illustrate different risers I umbilicals pull in I out methods using the retractable sheave assembly 001 according to the present disclosure to route the main rope 301 , thereby eliminating the need of the inboard sheave and outboard sheaves used in prior art hauling systems. The use of ballasting of the vessel to achieve a certain roll angle is therefore not required by the hauling system 30 according to the present disclosure.

[0050] In the SCR pull in / out method without Keel-hauling being shown in [fig. 8], the retractable sheave assembly 001 , when supported on the sheave trolley 310, extends outboard to a required distance with its transverse location locked. The vertical sheave 003 rotates to align with the required azimuth angle of the SCR slot so that the main rope 301 can be routed directly to the riser head 1 1 1 of SCR. Sufficient clearance is automatically achieved between the riser head receptacle 1 10 and riser head 1 11 being pulled up as the vertical sheave 003 is extended outboard and is aligned with the azimuth angle. After the riser head 1 1 1 is pulled up a sufficient amount above the riser head receptacle 1 10, the auxiliary line 121 is routed using the auxiliary side shell sheave 120 mounted on side shell 100, which can be used to pull the riser head 1 1 1 in an inboard direction so that it can be lowered down to sit within the riser head receptacle 1 10.

[0051] [Fig. 9] shows the retractable sheave assembly 001 being used to pull in / out a SCR with keel-hauling. The retractable sheave assembly 001 supported on the sheave trolley 310 extends outboard to a required distance, which is generally more than required for an SCR without keel-hauling, with its transverse location locked. The vertical sheave 003 rotates to align with the required azimuth angle so that the main rope 301 can be routed directly to the riser head 1 11 of SCR. Sufficient clearance between the riser head receptacle 1 10 and riser head 1 11 being pull up is automatically achieved as the vertical sheave 003 is extended outboard and aligned with the azimuth angle. After the riser head 1 1 1 is pulled up a sufficient distance above the riser head receptacle 110, the auxiliary line 121 routed using auxiliary sideshell sheave 120 mounted on side shell 100 can be used to pull the riser head 1 11 to inboard direction so that it can be lowered down to seat within the riser head receptacle 110. If the SCRs are pulled in via support tubes (not shown) replacing the riser head receptacle 110 located at the same location, then the main rope 301 can go through the support tube directly to pull in / out the SCR with keel-hauling.

[0052] [Fig. 10] shows the retractable sheave assembly 001 according to the present disclosure being used to pull in / out flexible risers or umbilicals through an I- tube 201 and a bell mouth 130 mounted on the side shell 100 as shown in Fig 10. In order to route the main rope 301 to l-tube 201 , the retractable sheave assembly 001 supported on the sheave trolley 310 only needs to the fully retracted position as shown in [fig. 6] and be locked with the vertical sheave 003 at its original location without any rotation.

[0053] It should be appreciated by the person skilled in the art that the above invention is not limited to the embodiment described. It is to be appreciated that modifications and improvements may be made without departing from the scope of the present invention.

[0054] It should be further appreciated by the person skilled in the art that one or more of the above modifications or improvements, not being mutually exclusive, may be further combined to form yet further embodiments of the present invention.

Claims

AMENDED CLAIMS received by the International Bureau on 08 February 2024 (08.02.2024)

1. An adjustable sheave assembly for a hauling system of a spread moored F(P)SO platform comprising: a carrier structure slidably supportable on a sheave trolley of the spread moored F(P)SO platform; a housing supported on the carrier structure; the housing respectively supporting a horizontal sheave rotatable about a generally vertical rotational axis, and a vertical sheave supported adjacent the horizontal sheave and rotatable about a generally horizontal rotational axis, the horizontal and vertical sheaves routing a main rope of the hauling system used to pull in / out operational equipment hung from the F(P)SO platform; wherein the carrier structure is supportable on the sheave trolley which is displaceable in a longitudinal direction along a riser pull in balcony of the F(P)SO platform, and the carrier structure is displaceable on the sheave trolley in a transverse direction relative to the longitudinal direction; and wherein the housing is rotatably supported on the carrier structure such that the vertical sheave is rotatably displaceable to different rotational positions about the vertical rotational axis of the horizontal sheave to thereby align the vertical sheave with an azimuth angle of an equipment slot of the operational equipment.

2. An adjustable sheave assembly according to claim 1 , wherein the operational equipment comprises a Steel Catenary Riser (SCR), and the equipment slot comprises a SCR riser head receptacle for the SCR mounted on the F(P)SO platform.

3. An adjustable sheave assembly according to claim 1 , wherein the operational equipment comprises a flexible riser or umbilical, and the equipment slot comprises a bell mouth mounted on the F(P)SO platform.

4. An adjustable sheave assembly according to claim 1 , wherein the vertical16AMENDED SHEET (ARTICLE 19)sheave is rotatably mounted on a side bracket extending from the housing.

5. An adjustable sheave assembly according to claim 1 , further comprising a rotation mechanism for controlling rotation of the housing.

6. An adjustable sheave assembly according to claim 5, wherein the rotation mechanism comprises a hydraulic cylinder interconnected to a locking gripper for interacting with rotation skidding pin holes provided on the housing.

7. An adjustable sheave assembly according to claim 1 , further comprising a rotation-locking mechanism for lock the housing at a required angle on the carrier structure.

8. An adjustable sheave assembly according to claim 7, wherein the rotationlocking mechanism comprises one or more locking pins for engaging rotation-locking pin holes provided within the housing.

9. An adjustable sheave assembly according to claim 1 , further comprising an actuating mechanism for controlling the displacement of the carrier structure in the transverse direction on the sheave trolley.

10. An adjustable sheave assembly according to claim 9, wherein the actuating mechanism comprises one or more hydraulic cylinders.[Claim 1 1 ] An adjustable sheave assembly according to claim 1 , further comprising a transverse locking mechanism for locking in position the carrier structure on the sheave trolley.

12. An adjustable sheave assembly according to claim 1 1 , wherein the transverse locking mechanism comprises at least one transverse locking pin for engaging transverse-locking pin holes provided on the sheave trolley.

13. An adjustable sheave assembly according to claim 1 , further comprising at least one carrier structure hold-down clamp fixed to the sheave trolley for retaining the carrier structure thereon.

14. A hauling system for a spread moored F(P)SO platform comprising an17AMENDED SHEET (ARTICLE 19)adjustable sheave assembly according to any one of the preceding claims.

15. A method of pulling in or out operational equipment hung from a F(P)SO platform using a hauling system having an adjustable sheave assembly according to any one of claims 1 to 10, comprising: a) if necessary, displacing the carrier structure on the sheave trolley in a transverse direction relative to the longitudinal direction of the riser pull in balcony; and b) rotating the housing on the carrier structure such that the vertical sheave is rotatably displaceable to thereby align the vertical sheave with an azimuth angle of the operational equipment.18AMENDED SHEET (ARTICLE 19)

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