EP4677192A1

EP4677192A1 - Connector assembly

Info

Publication number: EP4677192A1
Application number: EP24712895.2A
Authority: EP
Inventors: Daniel BOARDMAN
Original assignee: Bms Design Ltd
Current assignee: Bms Design Ltd
Priority date: 2023-03-09
Filing date: 2024-03-05
Publication date: 2026-01-14
Also published as: GB202303444D0; CN120731309A; JP2026508900A; WO2024184633A1; GB2628089A; KR20250162593A; AU2024232741A1

Abstract

The present application describes a connector assembly comprising a male part (200) removably locatable in a female part (104), wherein one of the male and female parts comprises at least one substantially flexible yet resilient retaining element (132) located at a fixed edge region thereof between at least one first support surface (118) and at least one second support surface (128) and extending radially to terminate at a free edge region (134) thereof beyond respective edges of the first and second support surfaces, and wherein the other one of the male and female parts comprises a substantially rigid and radially extending flange region (202) for engagement with the at least one retaining element (132) when at least one of the male and female parts is moved axially towards or away from the other one of male and female parts, and wherein the at least one resilient retaining element is configured to flex about a respective edge of the first and second support surfaces when urged in either axial direction by engagement with the substantially rigid flange region to locate the same on a first or second side of the resilient retaining element to respectively connect or disconnect the male and female parts. The connector assembly may be configured for automatically and repeatedly connecting and disconnecting a subsea bend stiffener connector (BSC) to a rigid structure hang-off location and/or a BSC to a subsea pipe/cable pull-head, or the like.

Description

CONNECTOR ASSEMBLY

The present invention relates to an assembly for connecting opposed end regions of two elongate members and in particular, but not exclusively, for connecting a bend stiffener to a subsea pipe or cable hang-off structure and/or pull-head.

A bend stiffener is typically a conical structure made of a flexible polymer material which encloses an elongate subsea member, such as a flexible riser, steel pipe, umbilical, power cable, or the like, to provide bend protection at a rigid structure hang-off location, such as an l-tube on a floating structure, monopile, oil rig/platform or jacket. An ‘l-tube’ is typically a vertical, platform-mounted tube for receiving the riser. Alternatively, a so-called ‘J-tube’ may be used in applications where the riser is not vertical where it enters the tube.

A bend stiffener connector (BSC) is typically a mechanism attached to the connecting end of the bend stiffener and used to locate and connect the resulting assembly to the hang-off structure, e.g. an l-tube. A typical BSC for offshore use is between around 0.5m to 2m in length. Once the BSC is in place, the subsea pipe pull-head must be disconnected to allow the pipe to continue to be pulled through the bend stiffener and the rigid structure hang-off and to be terminated above sea level. Typically, BSCs or latch mechanisms require manual intervention from a diver or a remotely operated vehicle (ROV) to either attach them to the hang-off or release the pull-head during installation. For example, US7,387,469 describes a clamping arrangement for clamping the flange of an l-tube hang-off to a corresponding flange of a bend stiffener assembly.

Due to operational conditions, a BSC can be required to be disconnected from the rigid structure hang-off up to ten times during its lifetime and typically manual intervention is required to perform this disconnection. This could be to install or remove a clamp below the bend stiffener assembly or to disengage any devices used to locate the BSC to the hang-off. After hang-off disconnection, or connection to the pull-head, components within the BSC are typically required to be manually reset either subsea or recovered onboard the vessel, all of which adds complexity, time and cost. A system that is fully autonomous requiring no manual intervention for up to at least ten installations, disconnections and re-installations is therefore desirable.

It is an aim of certain embodiments of the present invention to provide a connector assembly for automatically and repeatedly connecting and disconnecting two elongate members together.

It is an aim of certain embodiments of the present invention to provide a connector assembly and method for automatically and repeatedly connecting and disconnecting a subsea BSC to a rigid structure hang-off location and/or a BSC to a subsea pipe/cable pull-head, or the like.

According to a first aspect of the present invention there is provided a connector assembly comprising: a male part removably locatable in a female part, wherein one of the male and female parts comprises at least one substantially flexible yet resilient retaining element located at a fixed edge region thereof between at least one first support surface and at least one second support surface and extending radially to terminate at a free edge region thereof beyond respective edges of the first and second support surfaces, and wherein the other one of the male and female parts comprises a substantially rigid and radially extending flange region for engagement with the at least one retaining element when at least one of the male and female parts is moved axially towards or away from the other one of male and female parts, and wherein the at least one resilient retaining element is configured to flex about a respective edge of the first and second support surfaces when urged in either axial direction by engagement with the substantially rigid flange region to locate the same on a first or second side of the resilient retaining element to respectively connect or disconnect the male and female parts.

Optionally, the first support surface extends radially from the fixed edge region of the resilient retaining element towards the free edge region thereof by a greater distance than the second support surface such that an axial force required to disconnect the male and female parts is greater than an axial force required to connect the male and female parts. Optionally, the at least one first and second support surfaces are substantially annular and coaxially arranged with the at least one resilient retaining element.

Optionally, the at least one resilient retaining element is substantially annular to define a substantially continuous free edge region.

Optionally, the at least one resilient retaining element comprises a plurality of spaced apart free edge regions.

Optionally, the at least one resilient retaining element comprises a plurality of spaced apart and annularly arranged retaining elements.

Optionally, the free edge region of the at least one resilient retaining element comprises a tapered surface for engagement with the substantially rigid flange region during connection of the male and female parts.

Optionally, a ratio between a first radial distance M1 defined between the edge of the first support surface and the edge of the substantially rigid flange region, and a second radial distance M2 defined between the edge of the second support surface and the edge of the substantially rigid flange region is around 1 :3.

Optionally, a ratio between an overlap O of the at least one resilient retaining element and the substantially rigid flange region, and a thickness ET of the at least one resilient retaining element is around 3:2.

Optionally, the at least one resilient retaining element comprises a polyurethane material.

Optionally, the female part comprises the at least one resilient retaining element which extends radially inwardly to define a central aperture, and the male part comprises the rigid flange region extending radially outwardly proximal to an end region thereof. Optionally, the assembly comprises at least one first spacer extending from a base region of the female part to axially space the first support surface from the base region to define a cavity therebetween for accommodating the rigid flange region of the male part when connected to the female part.

Optionally, the assembly comprises at least one second spacer to axially space the second support surface from the first support surface.

Optionally, the at least one first and second spacers each comprise a hollow sleeve through which a bolt is located to clamp the assembly together.

Optionally, the first support surface and the second support surface are respectively provided by a first annular plate and a second annular plate.

Optionally, the at least one first and second spacers are provided by a continuous wall region extending substantially perpendicularly from and around the base region and the first and second support surfaces extend radially inwardly from the wall region.

Optionally, the base region comprises a central hole and a hollow and open-ended tubular portion extends axially from the central hole and beyond the first support surface.

Optionally, the tubular portion comprises at least one inwardly extending rigid flange region proximal to its open end for engagement with at least one substantially flexible yet resilient retaining element outwardly extending from a second male part axially insertable into and removably connectable with the open-ended tubular portion, wherein the at least one resilient retaining element of the second male part is located at a fixed edge region thereof between at least one first support surface and at least one second support surface and extends radially to terminate at a free edge region thereof beyond respective ends of the first and second support surfaces Optionally, the at least one resilient retaining element of the male part comprises a plurality of axially spaced apart resilient retaining elements each located between respective first and second support surfaces, wherein each first support surface extends radially from the fixed edge region of the resilient retaining element towards the free edge region thereof by a greater distance than the second support surface.

Optionally, the second male part is attachable to a subsea pull-head and comprises a central through bore for receiving a subsea cable or pipe.

Optionally, an l-tube hang-off structure defines the male part and a bend stiffener connector defines the female part for removably connecting a bend stiffener assembly mounted on a subsea cable or pipe to the l-tube hang-off structure.

According to a second aspect of the present invention there is provided a method of removably connecting a male part to a female part, comprising: axially moving a male part towards a female part or vice versa; engaging an outwardly extending first annular flange region of the male part with an inwardly extending second annular flange region of the female part, wherein one of the first and second flange regions comprises a substantially rigid flange region and the other one of the first and second flange regions comprises at least one substantially flexible yet resilient retaining element located at a fixed edge region thereof between at least one first support surface and at least one second support surface and extending radially to terminate at a free edge region thereof beyond respective edges of the first and second support surfaces; axially urging the substantially rigid flange region past the at least one resilient retaining element from a first side thereof towards a second side thereof to cause the same to flex about an edge of the first support surface; and locating the substantially rigid flange region on the second side of the at least one resilient retaining element to connect the male part to the female part.

Optionally, the method comprises selectively adjusting at least one of the following responsive to a desired bending stiffness of the at least one resilient retaining element: a material of the at least one resilient retaining element; a thickness of the at least one resilient retaining element; a shape of the at least one resilient retaining element; and an overlap of the at least one resilient retaining element and the substantially rigid flange region.

Optionally, the method comprises selectively adjusting at least one of the following responsive to a desired bending stiffness of the at least one resilient retaining element: a first radial distance M1 defined between the edge of the first support surface and the edge of the substantially rigid flange region; and a second radial distance M2 defined between the edge of the second support surface and the edge of the substantially rigid flange region.

Optionally, the first support surface extends further along the at least one resilient retaining element from the fixed end region thereof towards the free end region thereof than the second support surface.

Description of the Drawings

Certain embodiments of the present invention will now be described with reference to the accompanying drawings in which:

Figure 1 illustrates a cross sectional view of a subsea bend stiffener connected to an l-tube hang-off by a bend stiffener connector according to certain embodiments of the present invention;

Figure 2a illustrates the bend stiffener connector being offered up to the hang-off during a connecting operation;

Figure 2b illustrates the flange of the hang-off located in the bend stiffener connector and in turn the hang-off securely connected to the bend stiffener;

Figure 2c illustrates the subsea pipe or cable being pulled through the bend stiffener and hang-off by a pull-head attached to the pipe or cable; Figure 3 illustrates a cross-sectional schematic of a test to determine the effects of adjusting the configuration of the connector assembly according to certain embodiments of the present invention;

Figure 4 illustrates an alternative embodiment of the present invention; and

Figures 5a to 5h illustrate steps to connect and disconnect a pull-head to a bend stiffener connector according to the alternative embodiment of the present invention.

Detailed Description

As illustrated in Figure 1 , a bend stiffener assembly 100 according to certain embodiments of the present invention includes a bend stiffener 102 and a bend stiffener connector (BSC) 104. The bend stiffener 102 comprises a sleeve of material which is fitted around a flexible member 106 to be protected, such as a subsea pipe or cable. The sleeve is tapered from a wide end region 108 to a narrow end region 1 10. The sleeve may be a one-piece component or comprise substantially symmetrical halves that are bolted together over the flexible member to form the tapered sleeve therearound. This form of bend stiffener relies on the increased sectional diameter of the sleeve and the material modulus thereof to provide a resistance to bending in use. Other suitable forms of bend stiffener may be used.

The BSC 104 is fixed to the wide end region 108 of the bend stiffener 102 or it may be an integral part of the bend stiffener. For example, a main body of the BSC 104 may be a separate component attached to the substantially flat and relatively wide end of the bend stiffener by bolts or the like, or the BSC body may be integrally formed with the bend stiffener, such as a composite bend stiffener assembly comprising a polymer bend stiffener body moulded over a metal BSC body. Alternatively, for relatively light duty applications, the BSC body may be a polymer component formed integrally with the polymer bend stiffener body. The BSC body may be substantially one-piece to correspond with a one-piece bend stiffener, or the BSC body may comprise a plurality of sections connected together to correspond with a bend stiffener made up of more than one portion, such as two halves as described above. Further alternatively, the BSC body may be substantially one- piece and attached, such as by bolts, to the wide end region of a one-piece bend stiffener 102.

As illustrated in Figure 2a, the BSC 104 includes a cylindrical hollow body 1 12 defining a base region 1 14, a cylindrical wall region 116 and a first flange region 118 inwardly extending from the distal end of the wall region relative to the base region. The first flange region 1 18 is axially spaced from the base region 114 to define a cavity 1 19. The base and wall regions have an outer diameter which substantially corresponds to an outer diameter of the wide end region 108 of the bend stiffener 102. The base region 1 14 includes a central hole 120 and the first flange region 118 defines a central aperture 122. The aperture 122 is larger in diameter than the hole 120. A hollow and open-ended tubular portion 124 axially extends up from the hole 120 and through the aperture 122 to define the aperture as an annulus. The tubular portion 124 extends beyond the first flange region 118. The inner diameter of the hole 120 and a bore 126 extending along the tubular portion 124 are sized to accommodate the flexible member 106 therein. The outer diameter of the tubular member 124 is sized to insert into an l-tube or J-tube hang-off, and the central aperture 122 is sized to receive a flange region of the l-tube or J-tube hang off, as described further below.

A second inwardly extending flange region 128 is provided between the first flange region 118 and the base region 114 and spaced from the first flange region 118 to define a continuous slot or channel 130 around the wall region 116 for locating and supporting a substantially resilient retaining element 132. The retaining element 132 is annular to define a central aperture 134 having a diameter that is greater than the tubular member 124 to be spaced therefrom, yet less than a diameter of the flange region 202 of the l-tube hang-off 200. The resilient retaining element 132 is aptly a polymer material, such as a polyurethane rubber or plastic. As illustrated, the first flange region 118 above/distal to the retaining element 132 is longer than the second flange region 128 below/proximal to the retaining element, wherein proximal and distal are with respect to the base region 114 of the BSC. The inner, free end of each flange region 118,128 defines a hinge point for the resilient retaining element 132 to flex about in the proximal or distal directions with respect to the base region

114 of the BSC, i.e. approximately in either axial direction, such as upwardly or downwardly, in use. The different lengths of the first and second flange regions 118,128 define the cantilever length, and in turn the bending stiffness, of the retaining element 132 in each direction of flex. The relatively short second flange region 128 defines a relatively long cantilever length such that the bending stiffness of the retaining element 132 is relatively low and in turn the retaining element is more flexible about that hinge point. In contrast, the relatively long first flange region 118 defines a relatively short cantilever length such that the bending stiffness of the retaining element 132 is relatively high and in turn the retaining element is less flexible about that hinge point. This arrangement means a force required to urge the resilient retaining element 132 away from the base region 1 14 of the BSC is greater than a force required to urge the resilient retaining element 132 in the opposite direction towards the base region 1 14 of the BSC, and the length of one or both of the first and second flange regions may be chosen responsive to a desired bending stiffness of the retaining element and in turn a push-in or pull-out force respectively.

As illustrated in Figure 2a, a pull-head 300 coupled at a proximal end to a pull wire 302 is attached to a proximal end region of a subsea pipe 106 to allow the pipe to be pulled up to the fixed or floating structure, such as a monopile, oil rig/platform or jacket. The pull-head 300 and pipe 106 are located inside and pulled through the fixed l-tube hang-off 200 which draws the BSC 104, and the bend stiffener 102 attached thereto, towards the flange region 202 of the hang-off 200.

The tubular portion 124 of the BSC 104 slides into and along the inside of the tubular hang-off 200 such that the tubular portion 124 axially guides the retaining element 132 of the BSC towards the flange region 202 of the hang-off 200. The hang-off flange 202 engages the outer/upper surface of the retaining element 132 and further pulling of the pull-head 300 applies an axially-directed force on the retaining element to urge the same towards the base region 114 of the BSC. As this force increases and reaches an insertion threshold force to overcome the bending stiffness or flexural rigidity of the retaining element, the same is caused to axially flex inwardly towards the base region about the hinge point defined by the second flange region 128. Flexion of the retaining element 132 towards the base region 1 14 increases the diameter of the central aperture 134 until the flange region 202 of the hang-off 200 passes therethrough to be located in the cavity 119 and under the retaining element 132, i.e. between the retaining element and the base region of the BSC, as illustrated in Figure 2b. The base region 114 of the BSC acts as a stop surface to limit the axial movement of the BSC with respect to the hang-off flange 202, whilst the cavity 119 between the retaining element 132 and the base region 114 allows the retaining element to flex inwardly and also provides a degree of tolerance to ensure the hang-off flange 202 fully enters the cavity 1 19 and is properly located under the retaining element 132. The BSC 104, and in turn the bend stiffener 102, is now securely connected to the hang-off 200.

As illustrated in Figure 2c, the pull-head 300 and pipe 106 attached thereto can now be pulled through the hang-off and on to the fixed or floating structure for installation, connection, etc.

The BSC can be automatically decoupled from the hang-off flange 202 in a similar manner by reversing said axial movement of the BSC 104 with respect to the hang- off 200. This is achieved by controllably releasing/letti ng out the pull-wire from the wire spool/winch and allowing the pipe and bend stiffener assembly coupled thereto to lower under its own weight. This lowering urges the BSC away from the hang-off flange 202 and in turn applies a force to the under/inner surface of the retaining element 132 to cause it to flex upwardly/away from the base region 114 about the hinge point defined by the first flange region 118 of the BSC. In view of the first flange region 118 being longer and extending radially inwardly further along the retaining element than the second flange region 128, the force required to urge the hang-off flange 202 past the retaining element 132 in the opposed axial direction is greater than the force required to couple the hang-off to the BSC. This allows the BSC to be relatively easily coupled to the hang-off whilst also providing a secure connection when in situ.

Whilst the base region 114, wall region 1 16 and flange regions 118,128 of the illustrated BSC 104 are integral, the base region 114 and the flange regions 118,128 may be individual plates. The base plate may be axially spaced apart from the second plate defining the second flange region by a first set of annularly arranged tubular spacers/sleeves. The first plate defining the first flange region may be supported on and axially spaced apart from the second plate by a second set of annularly arranged tubular spacers/sleeves which are axially aligned with corresponding ones of the first set of spacers/sleeves. A bolt may extend through each pair of axially aligned spacers/sleeves and at least one nut may clamp the arrangement together and in particular the retaining element/s between the first and second plates. In this manner, the desired bending stiffness of the retaining element and in turn the push-in and/or pull-out force may be set by the central aperture diameter, i.e. annular width, of the first and second plates and/or the annular width of the retaining element itself. Furthermore, the first and/or second plate may be replaced with a differently configured plate having a different annular width to selectively adjust the bending stiffness of the retaining element in the respective axial direction and in turn the push-in or pull-out force to connect/disconnect the BSC from the hang-off.

Whilst the resilient retaining element 132 is shown as a single and continuous annular element, it may aptly comprise a plurality of annularly arranged and spaced apart elements. The or each retaining element may comprise an angled upper/outer surface which tapers inwardly to a relatively narrow free/inner end region. This gradual reduction in thickness towards the narrower free end region of the or each retaining element would decrease the bending stiffness of the cantilevered retaining element along its length from its fixed end to its free end and therefore allowing the or each retaining element to be shorter whilst still providing a sufficient retaining force. A tapered free end region also allows helps the hang-off flange 202 to slide over the retaining element during connection. The or each resilient retaining element 132 may comprise a polymer, composite, or elastomeric material, such as rubber or the like. Furthermore, one or more rows of retaining elements in the axial direction may be provided wherein each row comprising a single retaining element or a plurality of retaining elements is located between respective first and second flange regions to provide the respective hinge points/regions.

With reference to the schematic illustrated in Figure 3, the applicant carried out a significant number of non-trivial tests to determine the effects on connection and disconnection loads by adjusting the configuration of a connector assembly according to certain embodiments of the present invention. An annular substantially flexible yet resilient retaining element 332 was clamped between a first clamp member 318 (corresponding to the first flange region 118 of the embodiment illustrated in Figures 2a to 2b) and a second clamp member 328 (corresponding to the second flange region 128 of the embodiment illustrated in Figures 2a to 2b). An annular flange 352 extends outwardly from an axially moveable press 350 which corresponds to the l-tube hang-off 200 of the embodiment illustrated in Figures 2a to 2b. A load cell 355 measured the force required to urge the flange 352 past the retaining element 332 in both axial directions replicating connection (upwardly in Figure 3) and disconnection (downwardly in Figure 3) operations. The material and dimensions of the retaining element 332 were adjusted, as was the number of ‘fingers’ extending radially inwardly from a continuous outer fixed edge region of the annular retaining element. The overlap O between the retaining element 332 and the flange 352, and also the lateral spacing/gap M1 between the first clamp member 318 and the retaining element 332, and also the lateral spacing/gap M2 between the second clamp member 328 and the retaining element 332, were also adjusted to determine their effects on the forces required to connect and disconnect the flange 352 with respect to the retaining element 332.

The applicant identified that an annular polyurethane resilient retaining element 332 having a Shore D hardness of around 50, a thickness ET of around 40mm and a width (radial dimension from its inner edge to its outer edge) of around 100mm, combined with a gap M1 (between the end of a first clamp member 318 and the end of the hang-off flange 202) of around 40mm, a gap M2 (between the end of the second flange region 128 and the end of the hang-off flange 202) of around 120mm, and an overlap O (between the retaining element 132 and the hang-off flange 202) of around 60mm, performed particularly well for the specific application of a subsea BSC to hang-off connection wherein the hang-off flange is around 482mm in diameter. The retaining element 332 had a continuous outer fixed edge region and a plurality of flexible yet resilient ‘fingers’, i.e. projections, extending radially inwardly to define an intermittent inner free edge region. Aptly, the ratio between gap M2 and gap M1 is around 3:1 , i.e. gap M2 is around 3 times greater than gap M1 . Aptly, the ratio between overlap O and thickness ET is around 3:2, i.e. the overlap O is around 1 .5 times greater than the thickness of the retaining element. However, the various dimensions and material properties of the retaining element, and also the set-up configuration of the support flanges, the load flange and overlap etc. will be different for different technical applications and according to certain embodiments of the present invention can be selectively adjusted to achieve the desired connection and release loads.

In accordance with certain embodiments of the present invention, a flexible yet resilient retaining element is clamped between two surfaces in such a way that the load required to engage/disengage the mechanical latch part, e.g. a hang-off flange, in the connector can be selectively adjusted by adjusting the cross sectional shape, thickness and/or material properties of the resilient retaining element and/or the offset (M1 and/or M2) between the end of the retaining element and the end of the respective clamp face to adjust the load required to engage or disengage the mechanical latch part in the respective direction.

An alternative embodiment of the present invention may aptly include the resilient retaining element/s mounted to the other elongate member, such as on the male hang-off itself and a rigid flange of the female BSC may engage and flex the resilient element when the rigid flange is urged past and over the resilient element on the hang-off to connect the two components together, and vice versa during a disconnection operation. The flanged region of the hang-off may act as the longer first flange and the resilient retaining element may be clamped between the flanged region of the hang-off and a support ring or the like bolted to the flanged region which would provide the shorter second flange. In this manner, the flanged region of the hang-off will act as a hinge region for the resilient element to flex during a decoupling operation whilst requiring a larger force to urge the resilient element past and over the rigid flange of the BSC (compared to the force required during a coupling operation) to ensure a secure connection between the hang-off and bend stiffener in use.

Further alternatively, the resilient retaining element/s may be mounted on and extend radially outwardly from a male elongate member and the flanged region engageable with the retaining element/s during a connection operation in use may extend radially inwardly from the tubular wall of a female elongate tubular member. For example, as illustrated in Figures 4, the upper region of the tubular portion 426 of a BSC 404 according to certain embodiments of the present invention may include at least one inwardly extending annular flange, and preferably a plurality of axially spaced apart annular substantially flexible yet resilient retaining flanges 452,454,456. The upper region of the tubular portion 426 acts as a female connection part. Attached to the underside of a pull-head 300 is a hollow male connection part 460 through which the subsea cable or pipe 106 extends to couple to the pull-head. The male connection part 460 is mounted to the pull-head by bolts located through holes in an outwardly extending attachment flange 461 of the male connection part. At least one annular resilient retaining element, and aptly a plurality of axially spaced apart and outwardly extending resilient retaining elements 462,464,466, is mounted on, or forms a portion of, the male connection part 460. Each resilient retaining element 462,464,466 is located on or adjacent to an outwardly extending support flange 472,474,476 wherein a radial dimension of each support flange is less the respective retaining element such that each retaining element flexes against its corresponding support flange when urged axially in the downward direction by a force applied to the upper surface of the retaining element in use. The male connection part 460 may aptly comprise an upper mounting section 480 including the attachment flange 461 , a first (upper) annular resilient retaining element 462 clamped between a lower end of the upper mounting section 480 and a first support plate providing a first support flange 472, a first spacer 482, a second (intermediate) annular resilient retaining element 464 clamped between the first spacer and a second support plate providing a second support flange 474, a second spacer 484, and a third (lower) annular resilient retaining element 466 clamped between the second spacer 484 and a lower end plate providing a third support flange 476. This arrangement is aptly axially clamped together by bolts or tie rods or the like. Aptly, the upper mounting section 480 and the first and second spacers 482,484 also acts as support flange regions to provide a hinge point/region for the respective retaining element to flex on in the opposite (upward) axial direction when subjected to a force applied to the lower surface of the retaining element in use. As illustrated in Figure 5a, in use, and typically onboard a vessel, the male connection part 460 is axially inserted into the open upper end region of the tubular portion 426, i.e. the female connection part of the BSC 404. The lower resilient retaining element 466 is urged over and past all three retaining flanges 452,454,456 of the tubular female portion 426, the intermediate retaining element 464 is urged over and past the first and second retaining flanges 452,454, and the upper retaining element 462 is urged over and past the first retaining flange 452 such that each resilient retaining element is engaged under a respective one of the retaining flanges. The pull-head 300 (and in turn the cable/pipe 106 attached thereto) is now securely connected to the BSC 400 (and in turn the bend stiffener 102) via the tubular female portion 426 thereof. The attachment flange 461 of the upper mounting section 480 aptly engages with the upper end of the female tubular portion 426 to indicate that each of the resilient retaining elements 462,464,466 is in position under the respective retaining flange 452,454,456 for secure connection. To provide a degree of tolerance, each retaining element is allows to axially travel a distance below its respective support flange to ensure efficient and consistent coupling, such that when a tension is applied to the pull-wire 302 in use and the pull-head 300 and male connection part 460 are urged upwardly, a small gap 485 aptly appears between the attachment flange 461 and the upper end of the female tubular portion 426 when the resilient retaining elements of the male connection part 460 are moved upwardly to engage under each respective retaining flange 452,454,456 of the female connection part 426, as illustrated in Figure 5b.

In accordance with certain embodiments of the present invention, in view of the different radial lengths/widths of the first support regions (support flanges 472,474,476 provided by the respective plates) with respect to the second support regions (respectively provided by the spacers 482,484 and the upper mounting section 480), the force required to connect the male connection part 460 into the female connection part 426 is less than the force required to decouple the two parts.

The whole assembly can now be winched upwardly towards the l-tube hang-off 200 by the pull-wire such that the pull-head 300 and tubular female part 426 are pulled into the l-tube hang-off 200 until the flange 202 of the hang-off engages the top of the resilient retaining element/s 432 of the BSC 404, as illustrated in Figure 5c. As illustrated in Figure 5d, further pulling of the bend stiffener assembly towards the hang-off 200 applies a force on the resilient retaining element of the BSC until that force overcomes a bending stiffness/flexural rigidity of the retraining element to cause it to flex downwardly about the second (lower) support flange/plate and allow the hang-off flange 202 past and into the cavity 419 of the BSC. The BSC is now securely connected to the hang-off.

As illustrated in Figure 5e, further winching of the pull-wire urges the hang-off flange 202 against the base of the cavity 419 of the BSC which started to extract the male connection part 460 from the upper end region of the female tubular portion 426 of the BSC to decouple the pull head from the BSC and pull the cable/pipe through the bend stiffener assembly and hang-off.

As illustrated in Figure 5f, once the male connection part 460 is fully decoupled from the BSC 404, the bend stiffener assembly will lower under its own weight until the hang-off flange 202 engages under the retaining element/s 432 of the BSC to securely retain the bend stiffener assembly on the hang-off during pull-through of the cable/pipe, as further illustrated in Figure 5g.

As illustrated in Figure 5h, the bend stiffener assembly can be recovered by lowering the pull-head and male connection part 460 attached thereto back into the female tubular portion 426 of the BSC 404 to securely reconnect the two parts. The increased weight of the full assembly, including hang-off and cable/pipe attached thereto, provides a sufficient force to overcome the bending stiffness/flexural rigidity of the retaining element/s 432 of the BSC 404 and cause the same to flex upwardly in the opposite axial direction and allow the hang-off flange 202 to pass upwardly through the retaining element/s and decouple from the BSC and in turn the bend stiffener assembly. The bend stiffener assembly remains securely connected to the pull-head via the male/female connection parts 460/426 during decoupling of the assembly from the hang-off.

Certain embodiments of the present invention therefore provide a non-complex, two- way (push-pull) connector for automatically connecting and disconnecting opposed end regions of two elongate members and in particular, but not exclusively, for connecting and disconnecting a bend stiffener connector (BSC) to a subsea pipe or cable hang-off, without the need for costly and time-consuming manual intervention by, for example, a diver or an ROV. The connector according to certain embodiments of the present invention may be used for automatically connecting and disconnecting a BSC coupled to a subsea pipe or cable to a ‘bellmouth’ mounted on the end of a J-tube hang-off, for example. Alternatively, the connector according to certain embodiments of the present invention may be used for automatically connecting and disconnecting a pull-head to a bend stiffener assembly via the BSC. The connector according to certain embodiments of the present invention allows for full automation of installation and disconnection operations without the need for resetting as undesirably required for conventional BSCs. The connector attaches to a standard hang-off device without the need for a bespoke female receptacle as also undesirably required by conventional BSCs. No bespoke manual intervention tools or personnel are required. The pull-head de-latch system according to certain embodiments of the present invention is not dependent on a ‘weal link’ and cannot be unintentionally disconnected prior to intended use. The connector is relatively non-complex in design and operation and allows for repeatable installation and disconnection operations without the need for any manual resetting. Performance of the connector is also not compromised by marine growth or corrosion effects and desirably includes no mechanical moving parts which can wear, corrode and fail over time in a harsh subsea environment.

Claims

1. A connector assembly comprising: a male part removably locatable in a female part, wherein one of the male and female parts comprises at least one substantially flexible yet resilient retaining element located at a fixed edge region thereof between at least one first support surface and at least one second support surface and extending radially to terminate at a free edge region thereof beyond respective edges of the first and second support surfaces, and wherein the other one of the male and female parts comprises a substantially rigid and radially extending flange region for engagement with the at least one retaining element when at least one of the male and female parts is moved axially towards or away from the other one of male and female parts, and wherein the at least one resilient retaining element is configured to flex about a respective edge of the first and second support surfaces when urged in either axial direction by engagement with the substantially rigid flange region to locate the same on a first or second side of the resilient retaining element to respectively connect or disconnect the male and female parts.

2. The assembly according to claim 1 , wherein the first support surface extends radially from the fixed edge region of the resilient retaining element towards the free edge region thereof by a greater distance than the second support surface such that an axial force required to disconnect the male and female parts is greater than an axial force required to connect the male and female parts.

3. The assembly according to claim 2, wherein the at least one first and second support surfaces are substantially annular and coaxially arranged with the at least one resilient retaining element.

4. The assembly according to any preceding claim, wherein the at least one resilient retaining element is substantially annular to define a substantially continuous free edge region.

5. The assembly according to any of claims 1 to 3, wherein the at least one resilient retaining element comprises a plurality of spaced apart free edge regions.

6. The assembly according to claim 5, wherein the at least one resilient retaining element comprises a plurality of spaced apart and annularly arranged retaining elements.

7. The assembly according to any preceding claim, wherein the free edge region of the at least one resilient retaining element comprises a tapered surface for engagement with the substantially rigid flange region during connection of the male and female parts.

8. The assembly according to any preceding claim, wherein a ratio between a first radial distance M1 defined between the edge of the first support surface and the edge of the substantially rigid flange region, and a second radial distance M2 defined between the edge of the second support surface and the edge of the substantially rigid flange region is around 1 :3.

9. The assembly according to any preceding claim, wherein a ratio between an overlap O of the at least one resilient retaining element and the substantially rigid flange region, and a thickness ET of the at least one resilient retaining element is around 3:2.

10. The assembly according to any preceding claim, wherein the at least one resilient retaining element comprises a polyurethane material.

1 1 . The assembly according to any preceding claim, wherein the female part comprises the at least one resilient retaining element which extends radially inwardly to define a central aperture, and the male part comprises the rigid flange region extending radially outwardly proximal to an end region thereof.

12. The assembly according to claim 11 , comprising at least one first spacer extending from a base region of the female part to axially space the first support surface from the base region to define a cavity therebetween for accommodating the rigid flange region of the male part when connected to the female part.

13. The assembly according to claim 12, comprising at least one second spacer to axially space the second support surface from the first support surface.

14. The assembly according to claim 13, wherein the at least one first and second spacers each comprise a hollow sleeve through which a bolt is located to clamp the assembly together.

15. The assembly according to claim 14, wherein the first support surface and the second support surface are respectively provided by a first annular plate and a second annular plate.

16. The assembly according to claim 13, wherein the at least one first and second spacers are provided by a continuous wall region extending substantially perpendicularly from and around the base region and the first and second support surfaces extend radially inwardly from the wall region.

17. The assembly according to any of claims 12 to 16, wherein the base region comprises a central hole and a hollow and open-ended tubular portion extends axially from the central hole and beyond the first support surface.

18. The assembly according to claim 17, wherein the tubular portion comprises at least one inwardly extending rigid flange region proximal to its open end for engagement with at least one substantially flexible yet resilient retaining element outwardly extending from a second male part axially insertable into and removably connectable with the open-ended tubular portion, wherein the at least one resilient retaining element of the second male part is located at a fixed edge region thereof between at least one first support surface and at least one second support surface and extends radially to terminate at a free edge region thereof beyond respective ends of the first and second support surfaces.

19. The assembly according to claim 18, wherein the at least one resilient retaining element of the male part comprises a plurality of axially spaced apart resilient retaining elements each located between respective first and second support surfaces, wherein each first support surface extends radially from the fixed edge region of the resilient retaining element towards the free edge region thereof by a greater distance than the second support surface.

20. The assembly according to claim 18 or 19, wherein the second male part is attachable to a subsea pull-head and comprises a central through bore for receiving a subsea cable or pipe.

21 . The assembly according to any preceding claim, wherein an l-tube hang-off structure defines the male part and a bend stiffener connector defines the female part for removably connecting a bend stiffener assembly mounted on a subsea cable or pipe to the l-tube hang-off structure.

22. A method of removably connecting a male part to a female part, comprising: axially moving a male part towards a female part or vice versa; engaging an outwardly extending first annular flange region of the male part with an inwardly extending second annular flange region of the female part, wherein one of the first and second flange regions comprises a substantially rigid flange region and the other one of the first and second flange regions comprises at least one substantially flexible yet resilient retaining element located at a fixed edge region thereof between at least one first support surface and at least one second support surface and extending radially to terminate at a free edge region thereof beyond respective edges of the first and second support surfaces; axially urging the substantially rigid flange region past the at least one resilient retaining element from a first side thereof towards a second side thereof to cause the same to flex about an edge of the first support surface; and locating the substantially rigid flange region on the second side of the at least one resilient retaining element to connect the male part to the female part.

23. The method according to claim 22, comprising selectively adjusting at least one of the following responsive to a desired bending stiffness of the at least one resilient retaining element: a material of the at least one resilient retaining element; a thickness of the at least one resilient retaining element; a shape of the at least one resilient retaining element; and an overlap of the at least one resilient retaining element and the substantially rigid flange region.

24. The method according to claim 22 and 23, comprising selectively adjusting at least one of the following responsive to a desired bending stiffness of the at least one resilient retaining element: a first radial distance M1 defined between the edge of the first support surface and the edge of the substantially rigid flange region; and a second radial distance M2 defined between the edge of the second support surface and the edge of the substantially rigid flange region.

25. The method according to claim 24, wherein the first support surface extends further along the at least one resilient retaining element from the fixed end region thereof towards the free end region thereof than the second support surface.