Device for and method of repairing an anomaly on an outer surface of a cylindrical structure.

Abstract

A device for repairing an anomaly on an outer surface of a cylindrical structure comprises a substantially tubular flexible body 10 with first 11 and second 12 axial ends and non-continuous inner 13 a

Description

The present invention relates to a device for and method of repairing an outer surface of a cylindrical structure. Such cylindrical structures typically have an outer sheath. Such cylindrical structures may include subsea cylindrical structures, such as subsea pipes or subsea cables (i.e. electrical or mooring cables). Such cylindrical structures may further include in-air cylindrical structures, such as in-air pipes, in-air cables or topside parts of an offshore platform. Background to the Invention Subsea cylindrical structures, such as pipes and cables, typically have an outer sheath wrapped around them that acts as a barrier between the cylindrical structure and a corrosive environment such as seawater. Outer sheaths are generally made of a polymeric material which is easily damaged during handling of the cylindrical structure and / or through collision with other subsea objects. An anomaly on the outer sheath can expose the cylindrical structure to seawater, which can subsequently lead to corrosion of the cylindrical structure. If the outer sheath is not promptly and effectively repaired, failure of the cylindrical structure is likely. Current devices for repairing such anomalies include wraps that are difficult to deploy in subsea conditions and are of a metallic construction, making them susceptible to corrosion. It is an aim of the present invention to provide a device capable of repairing such anomalies that is quick and easy to fit in situ, particularly in dynamic subsea conditions, and through the operation of a remotely operated vehicle (ROV) or an autonomous underwater vehicle (AUV). Additional aims of the present invention include having the device be suitable for long-term subsea use, easily scalable for different cylindrical structure sizes and easily detachable from the cylindrical structure. Summary of the Invention A first aspect of the present invention provides a device for repairing an anomaly on an outer surface of a cylindrical structure, the device comprising: a flexible body having a substantially tubular form, first and second axial ends and non-continuous inner and outer surfaces forming first and second opposing lateral ends of the body; a gasket extending across the inner surface of the body; a first tension member mounted on the outer surface of the body substantially adjacent to the first lateral end of the body; a second tension member mounted on the outer surface of the body substantially adjacent to the second lateral end of the body; and a fastening mechanism engageable with both the first and second tension members and configured to urge the first and second tension members towards each other. Typically the cylindrical structure is a subsea cylindrical structure, typically a subsea cable or subsea pipe. The device may also be used on in-air cylindrical structures susceptible to corrosion, for example topside parts of an offshore platform. Typically the anomaly is a breach on an outer sheath of the cylindrical structure. Typically, the anomaly is a localised area of corrosion on an exposed substrate of the cylindrical structure, for example where a coating of the cylindrical structure has been damaged. In use, the body and gasket are wrapped around the cylindrical structure such that the gasket encompasses the anomaly. The fastening mechanism is then actuated to tighten the body around the subsea cylindrical structure. This compresses the gasket into the anomaly, forming a seal therebetween that prevents ingress, typically of water, through the anomaly. Optionally the body is non-metallic. Optionally the body is plastic. Optionally the body is formed of a nylon material, typically nylon 11 (PA 11) and / or nylon 12 (PA 12). Optionally the body is elastic and typically biased towards the tubular form. Optionally one of the lateral ends of the body is a tapered end.. Optionally the body is manufactured using an additive manufacturing process (also known as 3D-printing). Alternatively, the body may be manufactured using a computer numerical control (CNC) machining process. Optionally the body comprises first and second anchoring members each extending from and integrally formed with the outer surface of the body, wherein the first anchoring member is substantially adjacent to the first lateral end of the body, wherein the second anchoring member is substantially adjacent to the second lateral end of the body, wherein the first tension member is coupled to the outer surface of the body by the first anchoring member and the second tension member is coupled to the outer surface of the body by the second anchoring member. Optionally each anchoring member comprises a through-bore in which the respective tension member is received and secured. Optionally the first anchoring member is a first set of co-axial anchoring members and the second anchoring member is a second set of co-axial anchoring members. Optionally the body comprises a protective coating, optionally a ceramic coating, optionally a Cerakote® coating. Optionally the tension members are non-metallic, optionally plastic. Optionally the tension members are formed of a nylon material, typically nylon 11 or nylon 12. Optionally the tension members are manufactured using an additive manufacturing process or alternatively a CNC machining process. Optionally the gasket comprises first and second lateral ends, wherein the first lateral end of the gasket is substantially flush with the first lateral end of the body and wherein the second lateral end of the gasket is substantially flush with the second lateral end of the body. Optionally one of the lateral ends of the gasket is a tapered end. Optionally the tapered end of the gasket adjoins the tapered end of the body. Optionally the fastening mechanism comprises: a bolt connected to the first tension member and having a shaft with a threaded portion; a nut provided on the threaded portion of the shaft and selectively engageable with the second tension member; wherein relative rotation between the bolt and the nut when the nut is engaged with the second tension member urges the first and second tension members towards or away from each other. Optionally the bolt is pivotally moveable about the first tension member. Optionally the bolt further comprises a head, wherein the shaft is connected to the first member via a connecting member, wherein the connecting member comprises a first through-bore through which the first tension member is received and a second through-bore perpendicular to the first through-bore through which the shaft is received, wherein the head abuts against the connecting member when the fastening member urges the first and second tension members together. Optionally the connecting member is non-metallic, optionally plastic. Optionally the connecting member is formed of a nylon material, typically nylon 11 or nylon 12. Optionally the connecting member is manufactured using an additive manufacturing process or alternatively a CNC machining process. Optionally the shaft is more rigid than the body. Optionally the shaft is made of a metal such as steel. Optionally a hook configured to capture the second tension member is formed on the nut. Optionally the nut is non-metallic, optionally plastic. Optionally the nut is formed of a nylon material, typically nylon 11 or nylon 12. Optionally the nut is manufactured using an additive manufacturing process or alternatively a CNC machining process. Optionally the device comprises two fastening mechanisms. Optionally the shaft of each fastening mechanism is connected to the first tension member. Optionally the nuts of each fastening mechanism are connectable to each other. Optionally a pin is formed on the nut of one of the fastening mechanisms and a socket configured to receive the pin is formed on the nut of the other fastening mechanism. Optionally the gasket is formed of a rubber material, optionally nitryl butadiene rubber (NBR) and / or hydrogenated nitrile butadiene rubber (HNBR) and / or isobutylene-isoprene (HR). Optionally the body comprises a plurality of fins extending from and integrally formed with the outer surface of the body, wherein the fins are arranged at and along one of the axial ends of the body (typically at regular intervals), wherein each fin has a sloped face that slopes down from said one axial end of the body towards the other axial end of the body. Optionally a portion of the gasket extends beyond one of or both the first and second axial ends of the body. A second aspect of the invention provides a method sealing an anomaly on an outer surface of a cylindrical structure, the method comprising; providing a device according to the first aspect of the invention; positioning the device such that the anomaly is encompassed by device; wrapping the body and gasket around the cylindrical structure; and actuating the fastening mechanism to urge the first and second tension members towards each other. The steps of positioning the device such that the anomaly is encompassed by the device, wrapping the body and gasket around the cylindrical structure and actuating the fastening mechanism to urge the first and second tension members are optionally performed using a remotely operable vehicle (ROV), or optionally using an autonomous underwater vehicle (AUV), optionally by a subsea diver, optionally by a rope access technician or optionally by an operator with direct access to the anomaly. Optionally the method comprises: providing an opening tool configured to selectively maintain the device in an open configuration in which the device can be positioned such that the anomaly is encompassed by the device; and actuating the opening device to allow the body and gasket to wrap around the cylindrical structure. Optionally the opening tool is operable by the ROV. Optionally the opening tool is releasable from the device. Optionally the opening tool comprises a strap releasably connected to the first and second tension members and an adjustment mechanism configured to adjust and retain a length of the strap. Optionally the strap extends across the outer surface of the body. Optionally the method comprises the step of releasing the strap from the first and second tension members. Optionally the adjustment mechanism comprises a winch to which the strap is connected and arranged to selectively reel in and pay out the strap in order to adjust the length of the strap. Optionally the method comprises the step of engaging the nut with the second tension member, optionally using the ROV. Optionally the method comprises the step of driving relative rotation between the shaft and the nut to urge the first and second tension members towards each other. Optionally the method comprises the step of providing a torquing tool configured to drive relative rotation between the shaft and the nut when the nut is engaged with the second tension member. Optionally the torquing tool is interfaceable with the head of the bolt. Optionally the method comprises the step of engaging the torquing tool with the shaft, optionally the head of the shaft. Optionally the method comprises the step of operating the torquing tool to drive relative rotation between the shaft and the nut. Optionally the torquing tool is operable by the ROV. Optionally the method comprises the further steps of providing a further device in accordance with the first aspect of the invention, with the gasket of the device (i.e. a first device) having the portion extending beyond one of or both of the first and second axial ends of its respective body; positioning the further device such that the portion of the gasket of the device and the anomaly are encompassed by the further device; wrapping the body and gasket of the further device around the cylindrical structure; and actuating the fastening mechanism of the further device to urge the first and second tension members of the further device towards each other. The various aspects of the present invention can be practiced alone or in combination with one or more of the other aspects, as will be appreciated by those skilled in the relevant arts. The various aspects of the invention can optionally be provided in combination with one or more of the optional features of the other aspects of the invention. Also, optional features described in relation to one aspect can typically be combined alone or together with other features in different aspects of the invention. Any subject matter described in this specification can be combined with any other subject matter in the specification to form a novel combination. Various aspects of the invention will now be described in detail with reference to the accompanying figures. Still other aspects, features, and advantages of the present invention are readily apparent from the entire description thereof, including the figures, which illustrates a number of exemplary aspects and implementations. The invention is also capable of other and different examples and aspects, and its several details can be modified in various respects, all without departing from the spirit and scope of the present invention. Accordingly, each example herein should be understood to have broad application, and is meant to illustrate one possible way of carrying out the invention, without intending to suggest that the scope of this disclosure, including the claims, is limited to that example. Furthermore, the terminology and phraseology used herein is solely used for descriptive purposes and should not be construed as limiting in scope. In particular, unless otherwise stated, dimensions and numerical values included herein are presented as examples illustrating one possible aspect of the claimed subject matter, without limiting the disclosure to the particular dimensions or values recited. All numerical values in this disclosure are understood as being modified by "about". All singular forms of elements, or any other components described herein are understood to include plural forms thereof and vice versa. Language such as "including", "comprising", "having", "containing", or "involving" and variations thereof, is intended to be broad and encompass the subject matter listed thereafter, equivalents, and additional subject matter not recited, and is not intended to exclude other additives, components, integers or steps. Likewise, the term "comprising" is considered synonymous with the terms "including" or "containing" for applicable legal purposes. Thus, throughout the specification and claims unless the context requires otherwise, the word “comprise” or variations thereof such as “comprises” or “comprising” 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. Any discussion of documents, acts, materials, devices, articles and the like is included in the specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters formed part of the prior art base or were common general knowledge in the field relevant to the present invention. In this disclosure, whenever a composition, an element or a group of elements is preceded with the transitional phrase "comprising", it is understood that we also contemplate the same composition, element or group of elements with transitional phrases "consisting essentially of”, "consisting", "selected from the group of consisting of”, “including”, or "is" preceding the recitation of the composition, element or group of elements and vice versa. In this disclosure, the words “typically” or “optionally” are to be understood as being intended to indicate optional or non-essential features of the invention which are present in certain examples but which can be omitted in others without departing from the scope of the invention. References to directional and positional descriptions such as upper and lower and directions e.g. “up”, “down” etc. are to be interpreted by a skilled reader in the context of the examples described to refer to the orientation of features shown in the drawings, and are not to be interpreted as limiting the invention to the literal interpretation of the term, but instead should be as understood by the skilled addressee. Brief Description of the Drawings In the accompanying drawings: Figure 1 shows a perspective view of a device for repairing an anomaly on an outer surface of a cylindrical structure; Figure 2 shows a plan view of the device of Figure 1; Figure 3 shows a perspective view of a body and a gasket of the device of Figure 1; Figure 4 shows a perspective view of the body and gasket assembled together and showing an array of recesses provided on an inner surface of the gasket; Figure 5 shows a perspective view of first and second tension members of the device of Figure 1; Figure 6 shows a perspective view of bolts of fastening mechanisms of the device of Figure 1; Figure 7 shows a perspective view of nuts of the fastening mechanisms of the device of Figure 1; Figure 8 shows a perspective view of connecting members of the device of Figure 1; Figure 9 shows a side view an opening tool being used on the device of Figure 1; Figure 10 shows a plan view of the opening tool and device of Figure 9; Figure 11 shows a first modification of the device of Figure 1; Figure 12 shows a second modification of the device of Figure 1; and Figures 13-15 show a third modification of the device of Figure 1. Detailed Description of the Drawings Referring now to the drawings, Figures 1 and 2 show a device for repairing an anomaly on an outer surface, typically an outer sheath, of a cylindrical structure typically a subsea cylindrical structure such as a subsea pipe or subsea cable. As best seen in Figure 3, the device 1 comprises a substantially tubular body 10. The tubular body 10 has first and second axial ends 11, 12 and an axis along which the body 10 extends between its first and second axial ends 11, 12. The body 10 also comprises non-continuous inner and outer surfaces 13, 14, providing the body 10 with first and second lateral ends 15, 16 that are shown to overlap each other in Figure 3. Edges of the body 10 at its axial ends 11, 12 are mutually parallel with each and perpendicular to the mutually parallel edges at its lateral ends 15, 16. A length of the body 10 between its lateral ends 15, 16 is greater than a height of the body 10 between its first and second axial ends 11, 12. The body 10 also has a relatively low radial thickness between its inner and outer surfaces 13, 14. The inner and outer surfaces 13, 14 of the body 10 are substantially smooth. A plurality of anchoring members 17 project radially out from the outer surface 14 of the body 10. Each anchoring member 17 has a substantially rectangular form with two opposite and axially facing surfaces 17a; two opposite and laterally facing surfaces 171, a proximate end 17p adjoining the outer surface 14 of the body 10 and a radially distal end surface 17d that is convexly curved. Each anchoring member 17 also has a circular through-bore 17t extending between the two axially facing surfaces 17a in a direction parallel to the axis of the body 10. Each anchoring member 17 is integrally formed with the outer surface 14 of the body, with edges between the proximate end 17p of each anchoring member 17 and the outer surface 14 of the body 10 being filleted. In this example, the anchoring members 17 are arranged into first and second sets 18, 19 of four. In each set 18, 19, the anchoring members 17 are arranged in sequence and at intervals between the first and second axial ends 11, 12 of the body 10 with the through-bores 17t of each anchoring member 17 in co-axial alignment with each other. The anchoring members 17 of the first set 18 are positioned adjacent to but spaced from the first lateral end 15 of the body 10 while the anchoring members 17 of the second set 19 are positioned adjacent to but spaced from the second lateral end 16 of the body 10. Corresponding anchoring members 17 across the first and second sets 18, 19 are in axial alignment with each other. As best seen in Figure 2, the thickness of the body 10 gradually reduces towards its first lateral end 15 to form a tapered end 10t of the body 10. The body 10 is typically formed of a flexible, elastic and plastic material. Having the body 10 be flexible allows it to be opened up so it can receive and wrap around the cylindrical structure. Typically, the body 10 is manufactured such that it is biased towards the tubular form with overlapping lateral ends 15, 16 as seen in Figures 1-3. Materials the body 10 may be formed of include nylon 11 (also known as PA 11) and / or nylon 12 (also known as PA 12) and / or any other suitable material. The body 10 may also have a protective coating, typically a ceramic coating such as Cerotake®. The protective coating typically enhances the body’s 10 resistance against abrasion, wear, impact and corrosion in order to improve its durability within subsea conditions. As best seen in Figure 3, the device 1 further comprises a gasket 20 having a substantially tubular form. Figure 3 shows the gasket 20 having first and second axial ends 21, 22 and an axis along which the gasket 20 extends between its first and second axial ends 21, 22. Like the body 10, the gasket 20 has non-continuous inner and outer surfaces 23, 24 that provide the gasket 20 with first and second lateral ends 15, 16 that can be seen to overlap each other in Figure 3. Again like the body 10, edges of the gasket 20 at its axial ends 21, 22 are mutually parallel with each other and perpendicular to the mutually parallel edges at its lateral ends 25, 26. In this example, a length of the gasket 20 between its lateral ends 25, 26 and a height of the gasket 10 between its first and second axial ends 21, 22 are substantially equal to those of the body 10. The gasket 20 also has a radial thickness between its inner and outer surfaces 23, 24 that is greater than that of the body 10. While the outer surface 24 of the gasket 20 is substantially smooth, an array of recesses 27 is formed across the inner surface 23 of the gasket 20 (only shown in Figure 4 for clarity purposes). Each recess 27 is substantially square shaped and extends into a majority of the radial thickness of the gasket 20. As best seen in Figure 2, the thickness of the gasket 20 gradually reduces towards its first lateral end 25 to form a tapered end 20t of the gasket 20. As can be seen in Figure 4, the gasket 20 may have an additional tapered end 20t at its second lateral end 26. As best seen in Figure 1, the outer surface 24 of the gasket 20 is connected to the inner surface 13 of the body 10 such that the ends of the gasket 20 lie flush with those of the body 10. In particular, the first axial ends 11, 21 are flush with each other, the second axial ends 12, 22 are flush with each other, the first lateral ends 15, 25 are flush with each and the second lateral ends 16, 26 are flush with each other. Together, tapered ends 10t, 20t of the body 10 and gasket 20 form a pointed end of the device 1. The inner surface 23 of the gasket 20 is free to engage directly with the cylindrical structure when the device 1 is installed as will be set out further below. The gasket 20 is formed of an elastic and plastic material that is more flexible than the material the body 10 is formed of. The gasket 20 is typically manufactured as a sheet, rather than a tube, that is urged into a tubular form when coupled to the body 10 as described above. Materials that the gasket 20 may be formed of include a resilient material, for example a rubber material such as nitryl butadiene rubber (NBR), hydrogenated nitrile butadiene rubber (HNBR), isobutylene-isoprene (HR) or any other suitable material. As best seen in Figure 5, the device 1 further comprises first and second tension members 31, 32 each in the form of a rod extending along a respective axis. Each tension member 31, 32 has a circular cross section complimentary to that of the through-bores 17t on the anchoring members 17. Each tension member 31, 32 has a length such that it can be received by all of the through-bores 17t of a given set 18, 19 of anchoring members 17. As best seen in Figure 1, the first tension member 31 is received by the first set 18 of anchoring members 17 while the second tension member 32 is received by the second set 19 of anchoring members 17. Each tension member 31, 32 is typically secured within the respective set 18, 19 of anchoring members 17 via a friction or tolerance fit. The tension members 31, 32 are typically formed of a plastic material such as nylon 11 and / or nylon 12 and / or acetal and / or carbon fibre and / or any other suitable material. The device 1 further comprises two fastening mechanisms 2 each comprising a bolt 40 and either a first nut 50a or second nut 50b. As best seen in Figure 6, each bolt 40, a head 41 and a shaft 42 extending from said head 41 along an axis. In this example, each head 41 includes a radially outward extending flange 43 from which the shaft 42 extends along the axis; a stem 44, also extending along the axis from the flange 43 but in an opposite direction to the shaft 42.The head 41 also comprises two stubs 45 extending radially outwards from the stem 44, arranged diametrically opposite to each other and axially aligned with each other towards the free end of the head 41 remote from the shaft 42. Each shaft 42 comprises a threaded portion 46 provided on the exterior of the shaft 42 and extending along a majority of the length of the shaft 42 from its free end, and a smooth shank portion 47 extending along the remainder of the shaft between the flange 43 and the threaded portion 46. The head 41 as described above is designed to be interfaceable with tools of a remotely operable vehicle (ROV). In other examples, the head 41 may have a different design that it is more suited to interface with different tools. The bolts 40 are typically formed from a rigid material such as steel and / or acetal and / or any other suitable material. As best seen in Figure 7, each nut 50a,b has a substantially L-shaped form with first and second legs 51 a,b, 52a,b extending along a respective axis perpendicular to each and meeting at a junction point. A curved hook 53a,b is formed at the distal end of each first leg 51a,b, with a throat 54a,b of the hook 53a,b extending through the first leg 51a,b in a direction perpendicular to the axis of the first leg 51 a,b and parallel to the axis of the second leg 52a,b. Each throat 54a,b is dimensioned such that it can receive the second tension member 32. An internally threaded through-bore 55a,b extends through each first leg 51a,b in a direction perpendicular to both the axis of the first leg 51a,b and the axis of the second leg 52a,b. Each through-bore 55a,b is positioned between the hook 53a,b and the junction between the first and second legs 51 a,b, 52a,b. The through-bore 55a,b of each nut 50a,b is dimensioned to be complementary with the shaft 42 of each bolt 40. A pin 56a is formed at the distal end of the second leg 52a of the first nut 50a while a complimentary socket 56b is formed at the distal end of the second leg 52b of the second nut 50b. The pin 56a extends out from the second leg 52a of the first nut 50a parallel with the axis of said second leg 52a while the socket 56b extends into the interior of the second leg 52b of the second nut 50b parallel with the axis of said second leg 52b. In use, the first and second nuts 50a,b are connectable to each other to form a II-shaped configuration via the pin 56a and socket 56b arrangement (see Figure 1). The hooks 53a,b of the nuts 50a,b are arranged such that when connected in the II-shaped configuration, they curve in the same direction. In other words, openings into each of the throats 54a,b lie in the same direction. The engaging members 50a,b are typically formed from a plastic material such as nylon 11 and / or nylon 12 and / or any other suitable material. As best seen in Figure 8, the device further comprises two connecting members 60. Each connecting member 60 is formed by first and second substantially cylindrical elements 61, 62. Each element 61, 62 extends along a respective axis, with the axes being arranged perpendicular to each other. Each element 61, 62 is substantially D-shaped with opposed flat and curved surfaces. The elements 61, 62 are connected to each other at their flat surfaces. Each element 61, 62 comprises a through-bore 611, 62t extending through and along it’s the respective axis of the element 61, 62. Each through-bore 61t, 62t has a circular cross-section, with the through-bore 611 of the first element 61 being dimensioned to receive the second tension member 32 and the through-bore 52t of the second element 62 being dimensioned to receive the shaft 42 of the bolt 40, but not the head 41 of the bolt 40 (particularly the flange 43). The connecting members 60 are typically formed of a plastic material such as nylon 11 and / or nylon 12 and / or any other suitable material. When the device 1 is assembled, as seen in Figure 1, the pin 56a of the first nut 50a is received within the socket 56b of the second nut 50b such that the nuts 50a,b are in the U-shaped configuration and the threaded portion 46 of each shaft 42 is received within the through-bore 55a,b of its corresponding nut 50a,b. The nuts 50a,b are arranged such that the opening into each throat 54a,b is directed towards the head 41 of the bolt 40. Additionally, the hook 53a of the first nut 50a can be seen to capture the second tension member 32 within an uppermost (i.e. closest to the first axial end 11 of the body 10) interval between consecutive anchoring members 17 in the second set 19 while the hook 53b of the second nut 50b can be seen to capture the second tension member 32 within a lowermost (i.e. closest to the second axial end 12 of the body 10) interval between consecutive anchoring members 17. As best seen in Figure 1, each connecting member 60 connects the first tension member 31 and a respective bolt 40, with the through-bore 611 of each first element 61 receiving the first tension member 31 and the through-bore of each second element 62 receiving a respective shaft 42 of the bolt 40. One connecting member 60 is positioned within an uppermost (i.e. closest to the first axial end 11 of the body 10) interval between consecutive anchoring members 17 in the first set 18 while the other connecting member is positioned within a lowermost (i.e. closest to the second axial end 12 of the body 10) interval between consecutive anchoring members 17 in the first set 18. Each bolt 40 is directed through its respective connecting member 60 such that each shaft 42 passes over the overlapping lateral ends 15, 16, 25, 26 of the body 10 and gasket 20. Each connecting member 60, and consequently each bolt 40, is pivotally moveable about the first tension member 31. Additionally, each nut 50a,b can be selectively engaged with the second tension member 32 through movement of the corresponding bolt 40. As shown in Figures 9 and 10, the device 1 of Figures 1-8 is interfaceable with an opening tool 70 comprising a winch 71 and a strap 72 connected to said winch 71. The strap 72 is connectable to and releasable from each tension member 31, 32 and extends along the outer surface 14 of the body 10. As best seen in Figure 9, the strap 72 is typically connected to each tension member 31, 32 within a central interval between consecutive anchoring members 17 in each set 18, 19. The opening tool 70 further comprises a handle 73, allowing it to be held and moved by a remotely operable vehicle (ROV) (not shown). An example of how the device 1 may be used to repair an anomaly on an outer sheath of a subsea cylindrical structure will now be described. When the anomaly is located, a device 1 having dimensions suitable for repairing said anomaly is selected. Typically, the lengths of the body 10 and the gasket 20 are greater than the circumference of the subsea cylindrical structure to account for diametric tolerances of said structure. Furthermore, the heights of the body 10 and the gasket 20 may be chosen to be large enough such that the anomaly can be fully encapsulated within the body 10 and gasket 20. Prior to installation of the device 1, excess outer sheath is removed around the anomaly such that the anomaly is sufficiently uniform and extends substantially perpendicular to the length of the cylindrical structure, allowing for more accurate alignment of the device 1 with the anomaly. In cases where the subsea cylindrical structure is lying flat on the seabed, as opposed to being vertically or substantially vertically supported in a dynamic / water column region, a trench in the seabed is dug in the vicinity of the anomaly, allowing the device to more easily access the full circumference of the subsea cylindrical structure. An assembled device 1 is loaded on to the opening tool 70, with the strap 72 connected to the tension members 31, 32 and the strap 72 hauled in by the winch 71 such that the device 1 is maintained in an open configuration (not shown) in which there is an opening into the body 10 and gasket 20 between their respective first 15, 25 and second 16, 26 lateral ends. Additionally, the bolt 40 of each fastening mechanism 2 is pivoted via the connecting members 60 such that they do not extend over the opening. With the device 1 in the open configuration, the inner surface 23 of the gasket 20 can engage with and surround the outer sheath of the subsea cylindrical structure. While in this open configuration, the device 1 and the opening tool 70 are deployed down towards the anomaly, typically within an ROV tooling basket (not shown). An ROV then positions the device 1 such that the gasket 20 is positioned over the anomaly. While maintaining the device 1 in this position, the ROV operates the winch 71 to pay out the strap 72, allowing the body 10 and consequently the gasket 20 to return to their tubular forms, wrapping them around the cylindrical structure. As this happens, the first laterals ends 15, 25 and the second lateral ends 16, 26 of the body 10 and gasket 20 overlap each other. The pointed lateral end of the device 1 formed by the tapered ends 10t, 20t of the body 10 and gasket 20 helps an opposite lateral end of the device 1 (i.e. the second lateral ends 16, 26 of the body 10 and gasket 20) ride under or over the pointed end. Once the winch 71 has paid the strap 72 out fully, the strap 72 is released from each of the tension members 31, 32 and wound back into the winch 71. The opening device 70 can then be placed back into the ROV tooling basket. While continuing to maintain the device 1 in position, the ROV is further operated to pivot the bolts 40 via the connecting members 60 such that the shafts 42 lie across the overlapping lateral ends 15, 16, 25, 26 of the body 10 and gasket 20 and the second tension member 32 is received within the throats 54a,b of the nuts 50a,b (as is shown in Figure 1). A torquing tool (not shown), operable by the ROV and interfaceable with the head 41 of the bolt 40 via the stubs 45, is then used to drive rotation of each bolt 40 relative to its respective nut 50a,b such that the nut 50a,b is driven towards the head 41 of the respective bolt 40. As this happens, the hook 53a,b of each nut 50a,b captures and abuts against the second tension member 32 and the flange 43 of each bolt 40 abuts against its respective connecting member 60. This consequently drives the first and second tension members 31, 32 towards each other, securing the device 1 to the subsea cylindrical structure and compressing the gasket 20 into the anomaly, thus preventing any further water ingress into the outer sheath. While the method described above makes use of an ROV for positioning the device 1 and operating the tools, the device 1 may also be installed through other deployment means such as an autonomous underwater vehicle or diver deployment. The device 1 may also be used to repair in-air cylindrical structures that are susceptible to corrosion, such as topside parts of an offshore platform. In such cases where access to the in-air anomaly is restricted, positioning and actuation of the device 1 may be performed using rope access deployment means. Alternatively, in such cases where easy direct access to the anomaly is available, positioning and actuation of the device may be carried out manually. In addition to repairing cylindrical structures, the device may also carry sensors arranged to monitor the condition of the cylindrical structure. The body 10, the tension members 31, 32, the connecting members 60 and the nuts 50a,b can all be manufactured using an additive manufacturing process. This advantageously allows these parts to easily, quickly and inexpensively be manufactured on demand with dimensions tailored to the dimensions of the subsea cylindrical structure and the anomaly. Additionally, these parts are typically formed of a non-metallic material, making them resistant to corrosion while in subsea conditions. In examples where the device 1 is used to repair a subsea cable, having these non-metallic parts advantageously reduces the effects electromagnetic interference between the device 1 and the cable. Figures 11-14 show a series of modifications that can be made to the previously described device 1. These modifications facilitate the positioning of multiples devices adjacent to each other in series along the cylindrical structure. Figure 11 shows a first modification in which the body 10 comprises a plurality of radially outward extending fins 80 integrally formed on and upstanding from the outer surface 14 of the body 10. The fins 80 are arranged at the first axial end 11 along the length of the body 10 at regular intervals. Adjacent to the first axial end 11, a sloped face 81 of each fin 80 slopes down towards the second axial end 12. In use, a first device having the fins 80 is installed on the cylindrical structure. An ROV then positions a further device, also having the fins 80, in the open configuration over the cylindrical structure such that the second axial end 12 of the further device (i.e. the axial end not having the fins 80), is over / under the sloped faces 81 of the first device. The further device is then moved along the cylindrical structure until its second axial end 12 abuts the sloped faces 81 of the first device. From this position, the winch 71 is paid out, closing the further device. As this happens, the further device slides along and off the sloped faces 81, positioning it adjacent to the first device. Figure 12 shows a second modification in which the body 10 comprises a radially stepped out portion 90 at its first axial end 11 and extending along the length of the body 10. The stepped portion 90 forms a shoulder 91 pointing towards the first axial end 11 of the body on the inner surface 13 of the body 10. In an assembled device having the body 10 of Figure 12, the gasket 20 does not extend beyond the shoulder 91. Assembly of multiple devices having the body of Figure 12 is largely similar to that of multiple devices having the body 10 of Figure 11 as described above. With a first device installed, a further device in the open configuration is positioned over the cylindrical structure such that the second axial end 12 of the further device is over or under the shoulder 91 of the first device. The further device is then moved along the cylindrical structure until its second axial end 12 abuts the shoulder 91 of the first device, indicating that the further device is suitably adjacent with the first device. In this position, the stepped portion 90 of the first device encompasses the second axial end of the further device. The further device is then tightened and secured to the cylindrical structure. Figures 13-15 show a third modification. As seen in Figure 13, the gasket 20 is divided into a series of segments 20e, 20i. The series of segments 20e, 20i include two end segments 20e, each forming one of the lateral ends 25, 26 of the gasket 20 (only the end segment 20e forming the first lateral end 25 of the gasket 20 is shown for clarity purposes), and at least one intermediate segment 20i positioned between the end segments 20e. Adjacent segments are joined together by a series of interlocking teeth 20t formed on the lateral ends of the segments 20e, 20i. Other examples of a laterally divided gasket may just comprise two end segments 20e. As best seen in Figures 14 and 15, the gasket 20 may comprise first and second portions 28, 29. The first and second portions 28, 29 meet at a boundary 20b located proximate to the first axial end 21 of the gasket 20. From this boundary 20b, the first portion 28 extends to the second axial end 22 of the gasket 20 and the second portion 29 extends to the first axial end 21 of the gasket 20. The heights of the first and second portions 28 and 29 between the axial ends 21 and 22 are constant along the length of the gasket 20, with the height of the first portion 28 being substantially equal to that of the body 10 and the height of the second portion 29 being considerably shorter than that of the first portion 28. In the first portion 28, an array of recesses 27 similar to that shown in Figure 4 is formed across the inner surface 23 of the gasket 20. In the second portion 29, the inner surface 23 of the gasket is smooth and flat. As best seen in Figure 14, the inner surface 23 of the gasket 20 is level across the first and second portions 28, 29. As best seen in Figure 15, the outer surface 24 of the gasket 20 is smooth and flat across both the first and second portions 28, 29. However, the outer surface 24 of the gasket 20 across the second portion 29 is stepped down with respect to that of the first portion 28. In other examples, the outer surface 24 of the gasket 20 across the second portion 29 may slope up from the first axial end 21 of the gasket 20 to the boundary 20b between the first and second portions 28, 29. In use, the second portion 29 extends beyond the first axial end 11 of the body 10, 5 when the gasket is assembled within the body, providing a portion of the gasket 20 for an adjacent device to tighten around. 18 02 26

Claims

1. A device for repairing an anomaly on an outer surface of a cylindrical structure, the device comprising:5 a flexible body having a substantially tubular form, first and second axial endsand non-continuous inner and outer surfaces forming first and second opposing lateral ends of the body;a gasket extending across the inner surface of the body;a first tension member mounted on the outer surface of the body substantially10 adjacent to the first lateral end of the body;a second tension member mounted on the outer surface of the body substantially adjacent to the second lateral end of the body; anda fastening mechanism engageable with both the first and second tension members and configured to urge the first and second tension members towards 15 each other;wherein the fastening mechanism comprises:a bolt connected to the first tension member and having a shaft with a threaded portion;a nut provided on the threaded portion of the shaft and selectively 20 engageable with the second tension member;wherein relative rotation between the bolt and the nut when the nut is engaged with the second tension member urges the first and second tension members towards or away from each other;wherein the bolt is pivotally moveable about the first tension member; and25 wherein the device comprises two fastening mechanisms and the nuts ofeach fastening mechanism are connectable to each other.

2. The device of claim 1 wherein the body is non-metallic.30 3. The device of any one of the preceding claims wherein the body is elastic andbiased towards the tubular form.

4. The device of any one of the preceding claims wherein one of the lateral endsof the body is a tapered end.18 02 265. The device of any one of the preceding claims wherein the body comprises first and second anchoring members each extending from and integrally formed with the outer surface of the body, wherein the first anchoring member is substantially adjacent to the first lateral end of the body, wherein the second anchoring member is 5 substantially adjacent to the second lateral end of the body, wherein the first tension member is mounted on the outer surface of the body by the first anchoring member and the second tension member is mounted on the outer surface of the body by the second anchoring member.10 6. The device of any one of the preceding claims wherein the tension membersare non-metallic.

7. The device of any one of the preceding claims wherein the gasket comprisesfirst and second lateral ends, wherein the first lateral end of the gasket is 15 substantially flush with the first lateral end of the body and wherein the second lateral end of the gasket is substantially flush with the second lateral end of the body.

8. The device of claim 7 wherein one of the lateral ends of the gasket is a tapered end.

209. The device of any one of the preceding claims wherein the bolt further comprises a head, wherein the shaft is connected to the first member via a connecting member, wherein the connecting member comprises a first through-bore through which the first tension member is received and a second through-bore 25 perpendicular to the first through-bore through which the shaft is received, wherein the head abuts against the connecting member when the fastening member urges the first and second tension members together.

10. The device of claim 9 wherein the connecting member is non-metallic3011. The device of any one of the preceding claims wherein a hook configured to capture the second tension member is formed on the nut.

12. The device of any one of the preceding claims wherein the nut is non-35 metallic.18 02 2613. The device of any one of the preceding claims wherein the body comprises a plurality of fins extending from and integrally formed with the outer surface of the body, wherein the fins are arranged at and along one of the axial ends of the body, wherein each fin has a sloped face that slopes down from said one axial end of the 5 body towards the other axial end of the body.

14. The device of any one of the preceding claims wherein a portion of the gasket extends beyond one of or both of the first and second axial ends of the body.10 15. A method of sealing an anomaly on an outer surface of a cylindrical structure,the method comprising;providing a device according to any one of claims 1-14;positioning the device such that the anomaly is encompassed by the device; wrapping the body and gasket around the cylindrical structure; and15 actuating the fastening mechanism to urge the first and second tensionmembers towards each other.

16. The method of claim 15 wherein the steps of positioning the device such that the anomaly is encompassed by the device, wrapping the body and gasket around 20 the cylindrical structure and actuating the fastening mechanism to urge the first and second tension members are performed using a remotely operable vehicle (ROV), or an using an autonomous underwater vehicle (AUV), or by a subsea diver, or by a rope access technician or an operator with direct access to the anomaly.25 17. The method of claim 15 or 16 comprising:providing an opening tool configured to selectively maintain the device in an open configuration in which the device can be positioned such that the anomaly is encompassed by the device; andactuating the opening device to allow the body and gasket to wrap around the 30 cylindrical structure.

18. The method of claim 17 wherein the opening tool comprises a strap releasably connected to the first and second tension members and an adjustment mechanism configured to adjust and retain a length of the strap.CXIo co19. The method of any one of claims 15-18,wherein the device is in accordance with claim 14;wherein the method comprises the further steps of:providing a further device in accordance with any of claims 1-17;5 positioning the further device such that the portion of the gasket of thedevice and the anomaly are encompassed by the further device;wrapping the body and gasket of the further device around the cylindrical structure; andactuating the fastening mechanism of the further device to urge the10 first and second tension members of the further device towards eachother.

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