Abstract:
A subsea connector assembly is provided for automatically coupling a movable subsea structure to a tubular fixed subsea structure. The connector assembly comprises a male connector assembly, removably mountable to the movable subsea structure, and further comprising a throughbore, at least one first actuator member and at least one second actuator member. The connector assembly further comprises an adapter assembly, removably mountable to an end-fitting of a string of tubulars, comprising at least one first engagement member and at least one second engagement member, each of said at least one first and second engagement member are operable to be acted upon by said first and/or second actuator member so as to selectively release a locked engagement with said male connector assembly, allowing said adapter assembly to be moved through said throughbore of said male connector assembly.

Description:
[0001]    The present invention relates generally to the field of subsea pipelines and manifolds, and in particular, to the field of subsea fluid connections of flexible pipes or umbilical to a fixed structure including devices for limiting the bend of the flexible pipes or umbilicals. More particularly, the invention relates to a connector assembly allowing intervention-less installation of marine equipment such as, for example, a bend-stiffener. 
       INTRODUCTION 
       [0002]    In subsea operations, it is often required to connect a string of tubulars such as, for example, flexible pipes, flowlines or umbilicals to a fixed structure, such as an offshore floating platform or a vessel. A string of tubulars is hereinafter referred to as a “riser”. The riser may include cabling or control lines for equipment on the seafloor, so that they can be controlled remotely from the surface structure (i.e. the platform or vessel). Thus, risers are conduits for transferring hydrocarbon production fluids, such as, crude oil or gases to and from the surface. 
         [0003]      FIG. 1  shows a typical setup for subsea operation, where production fluid is transferred from at least one subsea well  10  to a floating production, storage and offloading unit  20 , also referred to as FPSO. A flexible riser  30  is used to transports the production fluid from the well  10 , or a seabed production field in case of multiple wells, to the FPSO  20  via turret  40 . Bend stiffeners  50  (only one connection is shown in  FIG. 1 ) are typically used where the flexible riser  30  joins the fixed structure (i.e. where the flexible riser  30  enters the turret  40  through an ‘I’- or ‘J’ tube  60 ), in order to protect the flexible riser  30  from excessive cyclic bending due to movement that may be caused by waves, current or wind, or which may simply be caused by the movement of the FPSO  20 . 
         [0004]    Often, the bend stiffener  50  is installed to the ‘I’- or ‘J’-tube  60  via a releasable connector assembly  70 . The releasable connector assembly  70  may comprises a male connector portion  72 , fitted to the bend stiffener  50 , and a female connector portion  74 , fitted to the ‘I’- or ‘J’-tube  60 . During installation, the male connector portion  72  is attached to the bend stiffener  50  and an end-fitting  32  of the riser  30  is located and attached to the male connector portion  72 . In particular, the end-fitting  32  of the riser  30  is located inside the throughbore of the male connector portion  72  and locked into place by, for example, a cam device, a clamp mechanism  78 , a latch- or other interlocking mechanisms (not shown). The attachment of the male connector portion  72  and the end-fitting  32  is typically completed in a workshop. 
         [0005]    Once the equipment (i.e. riser, end-fitting, bend stiffener and male connector portion) has been moved subsea, it is moved towards and into connection with the female connector portion  74  using a wire line  80  that is attached to the end-fitting  32  of the riser  30 . When the male connector portion  72  is located in the female connector portion  74 , it is interlocked with the female connector portion  74  so as to form a secure connection. Typically, a latch cam is used to couple male and female connector portions  72  and  74 . The riser  30  is then released from the engagement with the male connector portion  72  and drawn up and through the bend stiffener  50  and the ‘I’- or ‘J’-tube to be fixed into place at the FPSO  20 . 
         [0006]    The interlocking of the male and female connector portions, as well as, the release of the riser end-fitting  32  from the male connector portion  72  is conventionally done through external intervention using, for example, subsea divers  90  and/or a Remotely Operated Vehicles (ROV)  92 . In particular, the diver  90  or ROV  92  may operate the latch-cam  76  to secure the male connector portion  72  to the female connector portion  74 , and then release the clamp mechanism  78  that is fixating the riser end-fitting  32  to the male connector portion  72 . 
         [0007]    However, using subsea divers  90  or ROV&#39;s  92  to operate the connector assembly  70  is very time consuming and expensive. Also, using subsea divers  90  to operate the latch-cam  76  and/or the clamp mechanism  78  has certain risks and dangers, as well as, logistic challenges associated with people operating machinery in a subsea environment. Furthermore, using ROV&#39;s  92  or divers  90  is usually a relatively slow and tedious process, consequently increasing costs and the time spent to complete the operation. 
         [0008]    Accordingly, it is an object of the present invention to provide a subsea connector assembly that is suitable to operatively couple a moveable subsea structure with a fixed structure without additional external intervention. More particularly, it is an object of the present invention to provide a connector assembly suitable to automatically install a bend stiffener or bend limiter to a fixed structure (e.g. FPSO) without the need of intervention from ROV&#39;s or subsea divers. 
       SUMMARY OF THE INVENTION 
       [0009]    A preferred embodiment of the invention seek to overcome one or more of the disadvantages of the prior art. 
         [0010]    According to a first embodiment of the present invention, there is provided a subsea connector assembly for automatically coupling a movable subsea structure to a tubular fixed subsea structure, comprising: 
         [0011]    a male connector assembly, removably mountable to the movable subsea structure, comprising a throughbore, at least one first actuator member and at least one second actuator member; 
         [0012]    an adapter assembly, removably mountable to an end-fitting of a string of tubulars, comprising at least one first engagement member and at least one second engagement member, each of said at least one first and second engagement member are operable to be acted upon by said first and/or second actuator member so as to selectively release a locked engagement with said male connector assembly, allowing said adapter assembly to be moved through said throughbore of said male connector assembly. 
         [0013]    This provides the advantage that marine equipment, such as a bend stiffener, can be installed by simply engaging the actuator members with the engagement members. In particular, once the male connector assembly is fitted to, for example, a bend stiffener, the retro-fittable adapter assembly then allows the end-fitting of the flexible riser to be securely but releasably attached within the throughbore of the male connector assembly. When the male connector assembly, and attached bend stiffener and riser end-fitting, engages with the female connector, the first actuator member is automatically activated allowing the riser end-fitting to be moved longitudinally within the throughbore of the male connector portion to activate the at lease one second actuator and release the riser end-fitting out of engagement with the male connector assembly. Therefore, as soon as the bend stiffener is securely coupled to the fixed structure (i.e. ‘I’-tube), the riser is automatically released to be moved up and through the connector assembly and into engagement with the fixed structure. No external intervention by a subsea diver and/or ROV is required during this operation, thus, saving considerable time and costs for installing marine equipment such as a bend stiffener. 
         [0014]    Each of said at least one first and second engagement member may be operable to be acted upon by said at least one first and/or second actuator member so as to selectively lock an unlocked engagement with said male connector assembly, allowing said adapter assembly to fixatingly engage with said male connector assembly. 
         [0015]    This provides the advantage that previously installed marine equipment, such as bend stiffeners, can be removed from its attachment with a fixed structure, by interactively engaging the engagement members of the adapter assembly, connected to the riser end-fitting, with the actuator members of the male connector assembly. The engagement members are brought into engagement with the actuator members through longitudinal movement of the attached adapter assembly within the throughbore of the male connector assembly. External intervention by subsea divers and/or ROV&#39;s is not required saving significant time and costs for such an operation. 
         [0016]    Advantageously, the second actuator member may be operable by matingly interlock said male connector assembly with a corresponding female connector. 
         [0017]    Preferably, the first actuator member may be a circumferential groove on an inner wall of said throughbore that is adapted to operatively engage with said at least one first and/or second engagement member. Advantageously, the groove is chamfered on its downhole side when in-situ. 
         [0018]    This provides the advantage that the first engagement members and the first actuator member do not require a specific angular alignment to be operable. Therefore, correct function of the engagement between the first actuator member and the first engagement member is ensured in any angular position of the adapter assembly relative to the concentric male connector assembly. 
         [0019]    The at least one second actuator member may be a pin slidingly arranged in an aperture through said male connector assembly, said aperture is positioned so as to coincide with said groove, allowing movement of said pin between a first pin position, where at least part of a proximal end portion of said pin projects out of said aperture past an outer male connector assembly wall, and a second pin position, where at least part of a distal end portion of said pin projects into said groove. Advantageously, the pin may be adapted to be indexed in any one of said first and second pin position via a first indexing mechanism. 
         [0020]    Suitably, the at least one first engagement member is arranged circumferentially about an outer surface of said adapter assembly. In particular, if there are more than one engagement member (e.g. three), than the multiple engagement members are arranged circumferentially about the outer surface, preferably equidistant to each other. This provides the advantage of an axially symmetrical distribution of any forces acting on the multiple engagement members. 
         [0021]    Advantageously, the at least one first engagement member may be spring biased radially outwardly from said adapter assembly. 
         [0022]    The at least one first engagement member may be adapted to move between a first engaged position, where said at least one first engagement member projects into said groove, and a first disengaged position, where said at least one first engagement member is moved out of engagement with said groove. Advantageously, the at least one first engagement member may be adapted to be selectively locked in said first disengaged position via a second indexing mechanism. Even more advantageously, the second indexing mechanism may be lockable in a retracted position so as to prevent any engagement with said at least one first engagement means. Suitably, the at least one first engagement member may be adapted to be indexed in said first engaged position. 
         [0023]    The at least one second engagement member may be arranged coplanar with said at least one first engagement member, said second engagement member may also be adapted to move between a second engaged position, where said at least one second engagement member projects into said groove, and a second disengaged position, where said second engagement member is moved out of engagement with said groove. Advantageously, the at least one second engagement member may be adapted to be indexed in said second engaged and disengaged position via a third indexing mechanism. 
         [0024]    Furthermore, the male connector assembly may comprise a plurality of circumferentially arranged first and/or second actuator members, and wherein said adapter assembly may comprise a plurality of second engagement members operatively corresponding to said plurality of second actuator members. Advantageously, all of said plurality of second engagement members may be circumferentially alignable with corresponding said plurality of second actuator members. 
         [0025]    This provides the advantage that each one of the plurality of engagement members can be aligned with and engaged by its corresponding second actuator member. In particular, this provides the further advantage of improved functionality and safety, since the second engagement members are only activated (e.g. released) when all of the actuator members are engages simultaneously. 
         [0026]    Advantageously, the male connector assembly may be adapted to matingly interlock with a corresponding female connector via a latch mechanism located on the female connector. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]    A preferred embodiment of the present invention will now be described, by way of example only and not in any limitative sense, with reference to the accompanying drawings, in which: 
           [0028]      FIG. 1  [Prior Art] shows an example of a typical offshore setup for producing hydrocarbons from a subsea well and transferring the fluids to and from a FPSO via a flexible riser, wherein the riser is protected by a bend stiffener at the point of entering an ‘I’-‘J’-tube of the FPSO; 
           [0029]      FIG. 2  shows an example of a bend stiffener when coupled to a suitable female connector assembly mounted to an ‘I’-tube using the connector assembly of the present invention; 
           [0030]      FIG. 3  shows a perspective view of (a) the bend stiffener and the attached male connector assembly, (b) a riser end-fitting with an attached adapter assembly and (c) a female connector assembly suitable to be coupled with the connector assembly of the present invention; 
           [0031]      FIG. 4  shows (a) a perspective exploded view of the riser end-fitting and the adapter assembly before it is assembled and (b) a cross section of the riser end-fitting and the attached adapter assembly; 
           [0032]      FIG. 5  shows (a) a perspective view and (b) a perspective sectional view of the male connector assembly before it is mounted to the bend stiffener; 
           [0033]      FIG. 6  shows a perspective sectional view of the male connector assembly (a) when the riser end-fitting is lowered into the throughbore of the male connector assembly and (b) when the first engagement members are in engagement with the first actuator member (groove) and the riser end-fitting is then moved about a longitudinal axis to rotationally aligned the second engagement members with corresponding second actuator members; 
           [0034]      FIG. 7  shows a perspective sectional view of the male connector assembly (a) when first and second engagement member tools are placed and (b) used to move the first and second engagement members into the “primed” position; 
           [0035]      FIG. 8  shows a detailed perspective sectional view of (a) the second engagement member when in engagement with the first actuator member (groove) (the second actuator member (poppet) is indexed in the “primed” position), and (b) the first engagement member when in engagement with the first actuator member (groove) (the first engagement member is indexed in its “primed” position), so as to fixedly position the riser end-fitting within the male connector assembly; 
           [0036]      FIG. 9  shows a sequence of coupling the male connector assembly into corresponding female connector assembly (a) pulling male connector into the female connector, (b) moving passed the latch clamp of the female connector, (c) activating second actuator member (poppet) through engagement with the inner wall of the female connector and disengaging second engagement member with the first actuator member (groove), and (d) lowering the riser end-fitting within the throughbore of the male connector and interlocking the male connector with the female connector via the latch clamp; 
           [0037]      FIG. 10  shows a detailed perspective view of (a) the second engagement member and corresponding second actuator member (poppet), when the second actuator member (poppet) is indexed in its second “activated” position, and (b) the first engagement member when out of engagement with the first actuator member (grove) and locked in its first “disengaged” position; 
           [0038]      FIG. 11  shows a perspective sectional view of the connector assembly when the riser end-fitting is released and (a) moved through and out of the male connector assembly and (b) continues to be pulled through the ‘I’-tube; 
           [0039]      FIG. 12  shows a perspective view of a sequence (a)-(d) when removing the adapter assembly from the riser end-fitting for storage after the bend stiffener has been coupled to the ‘I’-tube; 
           [0040]      FIG. 13  shows a perspective sectional view of a sequence (a)-(d) when lowering the riser end-fitting and attached adapter assembly back into locked engagement with the male connector assembly; 
           [0041]      FIG. 14  shows a perspective sectional view of a sequence (a)-(d) when decoupling the male connector assembly (and attached bend stiffener) from the ‘I’-tube and its attached female connector assembly, and 
           [0042]      FIG. 15  shows a detailed perspective sectional view of the male connector assembly when (a) disengaging the first engagement member using the engagement member tool, and (b) retracting the riser end-fitting from the throughbore of the male connector assembly. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0043]    In the context of this specification, terms such us “top” and “bottom”, “uphole” and “downhole”, and “upper” and “lower” refer to respective sides of the equipment when in situ, i.e. when the equipment is installed within the arrangement providing a connection between the FPSO and the subsea well/reservoir. In particular, the terms “top”, “upper” and “uphole” refer to the side of the equipment directed towards the surface when in situ, the terms “bottom”, “lower” and “downhole” refer to the side of the equipment directed towards the seabed or seafloor when in situ. In addition, the term “coupled” means either a direct or indirect connection between one or more objects or components. Also, in this specification the term “latching dog” or “dog” may be understood to mean a mechanical device suitable for holding, gripping and/or fastening, comprising a spike, bar, hook, deadbolt, pin or the like. The term “bend stiffener” may refer to any one of a bend-stiffener, -restrictor or -limiter. The terms “fixed structure”, “turret”, “I-tube” and “J-tube” may be used interchangeably. A “riser” is understood to mean any string of tubulars or umbilicals suitable to operatively connect the subsea well or any other seafloor equipment with the fixed structure, e.g. a FPSO vessel. The term “intervention-less” is understood to mean without intervention from an ROV, subsea divers or any other device operated subsea to install the equipment. The terms “connector assembly”/“connector” and “adapter assembly”/“adapter”/“adapter ring” may be used interchangeably. 
         [0044]    Referring now to  FIG. 2 , a preferred embodiment of the present invention is shown. In particular, a fully assembled bend stiffener  50  is coupled to a female connector  74  of an ‘I’-tube  60  utilizing the connector assembly  100  of the present invention.  FIGS. 3(   a )-( c ) show each of the main assembled parts separately. In particular, a male connector  102  is mounted to the top end of a typical bend stiffener  50 , an adapter assembly  104  is mounted to the lower end of a riser end-fitting  32 , and a typical female connector  74 , having a latch mechanism  76  is mounted to an ‘I’-tube. The female connector  74  is typically adapted to interlockingly receive the male connector  102 . 
       Prior Assembly of the Riser/Male Connector and “Priming” 
       [0045]    Before the bend stiffener  50  can be installed to the ‘I’-tube subsea, the male connector  102  and end-fitting adapter  104  have to be mounted to the bend stiffener  50  and the riser end-fitting  32 , respectively. This assembly is usually completed by technicians on the FPSO  20 . 
         [0046]    As shown in  FIG. 4(   a ) and as shown in detail in  FIG. 4(   b ), the adapter ring  104  is slid over the riser  30  to the bottom end of the riser end-fitting  32  and fixed to the end-fitting  32  utilizing a mounting ring  106  and mounting bolts  108 . In this particular example, the adapter  104  includes three primary collets  110  that are installed within recesses  118  arranged circumferentially equidistant about the outer surface of the adapter ring  104 . The primary collets  110  are slidable within the recesses  118  and spring biased in a radially outward direction by stacked conical washers  112 . A lower edge of the protruding primary collets  110  is suitably chamfered, wherein the protruding part of top edge provides a flat surface. A locking pin  114  is adapted to index the primary collet  110  in a first position, where at least part of the primary collet  110  protrudes out of the outer surface of the adapter ring  104 , and lock the primary collet  110  in a second position, where the primary collet  110  is fully retracted in the adapter ring  104 . The locking pin  114  is spring biased in a direction towards the primary collet  110 , and can be locked when the primary collet  110  is in its second position via a locking pin retaining grub screw  116 . 
         [0047]    The adapter assembly  104  further includes three secondary collets  120  installed within suitable recesses  122  that are arranged circumferentially equidistant between the primary collets  110  about the outer surface of the adapter ring  104 . An indexing pin  124  is adapted to index the secondary collet  120  in a first position, where at least part of the secondary collet  120  protrudes out of the outer surface of the adapter ring  104 , and a second position, where the secondary collet  120  is fully retracted in the adapter ring  104 . The indexing pin  124  is spring biased towards the secondary collet  120 . 
         [0048]    It is understood by the skilled person in the art that any suitable number of primary and secondary collets  110 ,  120 , and any suitable biasing means for the primary collets  110 , as well as, the indexing pins  124  and locking pins  114  may be used with the adapter assembly  104 . 
         [0049]    A close up view of the male connector  102  and a cross section through the male connector  102  is shown in  FIGS. 5  ( a ) and ( b ). The male connector  102  has a flange portion  103  configured to be coupled with the top end of a bend stiffener  50 . The profile of the outer surface of the male connector  102  is a typical “Diverless Bend Stiffener Connector” (DBSC) profile suitable to engage and interlock with a corresponding female connector  74  having a latching mechanism  76 . The male connector  102  further comprises three poppets  126  slidingly mounted in apertures arranged  127  at a lower midsection and circumferentially equidistant about the outer surface of the male connector  102 . 
         [0050]    A circumferential groove  128  is arranged at the inner surface of a throughbore  130  of the male connector  102  so as to intersect with the apertures  127  of the poppets  126 . The groove  128  has a lower edge  130  that is chamfered to matingly engage with the lower edge of the protruding primary collet  110 . The upper edge of the groove  128  is substantially horizontal and flat. 
         [0051]    A poppet indexing pin  132  is arranged to index the poppet  126  in a first position, where at least part of the poppet  126  projects out of the outer surface of the male connector  102 , and a second position, where at least part of the poppet  126  projects into the groove  128 . When the poppet  126  is in the second position, it does not protrude past the outer surface of the male connector  102 . 
         [0052]    In addition, secondary collet retaining slots  134  are arranged in the groove  128  around each of the poppets  126  and apertures  127 . The secondary collet retaining slots  134  are configured to receive the protruding part of the secondary collets  120 . 
         [0053]    Before sliding the male connector  102  over the riser end-fitting  32 , the secondary collets  120  are indexed in the second position, wherein the locking pin  114  is locked in a retracted position by the retaining grub screw  116  so as to not engage with the primary collet  110 . The primary collets  110  are therefore urged radially outwards by the stacked conical washers  112 . When sliding the riser end-fitting  32  into the throughbore  130  of the male connector  102 , the primary collets  110  are pushed back through the engaging chamfered lower edge and snap out when engaging with the groove  128 . The attached riser end-fitting  32  is then lifted back up and the secondary collets  120  are rotationally aligned with respective secondary collets retaining slots  134  and poppets  126 . 
         [0054]    Once the secondary collets  120  are aligned, a hex T-bar  400  is used to remove the retaining grub screw  116  and release the locking pin  114  to be urged towards and index the primary collet  110  into its first position. A setting tool  402  is then inserted into the secondary collet  120  used to pull and index the secondary collets  120  and poppets  126  into their respective first positions. Hex T-bar  400  and setting tool  402  are removed. 
         [0055]      FIG. 8  ( a ) shows a detailed close-up view of a secondary collet  120  and respective poppet  126  when both are indexed in their first position. A small clearance is provided between the upper side of the protruding secondary collet  120  and the upper edge of the groove  128 , and the lower side of the secondary collet  120  and the lower edge of the groove  128 .  FIG. 8  ( b ) shows a detailed close-up view of a primary collet  110  indexed in its first position by the now released locking pin  114 . The primary collets  110  cannot be forced back into their respective recesses  118  unless all secondary collets  120  are pushed back by all the poppets  126 . 
         [0056]    The riser end-fitting  32  (as well as connected riser  30 ) and attached male connector  102  (as well as connected bend stiffener  50 ) are now “Primed” for subsea installment. 
       Subsea Installation of the Bend Stiffener 
       [0057]      FIGS. 9  ( a )-( d ) show a sequence of a subsea installation of the bend stiffener  50 . The “primed” riser end-fitting is first connected to a suitable wire line  80  (not shown) that is pulled in through the ‘I’-tube  60  from the FPSO  20 . The riser end-fitting  32  and attached male connector  102  are then pulled up (white and black arrows) into the female connector  74  so that the upper lip of the male connector  102  engages with the female latch mechanism  76  to move it back and let the male connector  102  pass. At the point where the female latch mechanism  76  is about to snap shut to retain the male connector  102  and interlock with the female connector  74 , the poppets  126  are not yet in contact with the inner wall of the female connector  74 . When the male connector is pulled past the female latch  76 , all poppets  126  are forced into their second position indexing the secondary collets  120  into respective second positions (i.e. activated). The male connector  102  is then lowered onto the female latch  76  so that the riser end-fitting  32  continues to be lowered due to the weight of the riser  30 . An optional shoulder (not shown) arranged within the throughbore  130  may be utilized to stop the downward movement of the riser end-fitting  32  at a predetermined location within the throughbore  130 . Thus, when exiting the groove  128 , both, primary and secondary collets  110 ,  120  are pushed back into respective recesses  118 ,  122 . When the primary collets  110  are pushed back, the locking pin  114  automatically engages with the primary collet so as to lock it in the second position, i.e. the primary collet  110  cannot be moved back out without releasing the engagement with the locking pin  114 . The secondary collets  120  are indexed in their second position clear of any engagement with the circumferential groove  128 . 
         [0058]      FIGS. 10  ( a ) and ( b ) show a detailed close-up view of a secondary and primary collet  120 ,  110  when respectively indexed and locked in the second position. 
         [0059]    The riser end-fitting  32  and attached riser  30  are now detached from engagement with the male connector  102  and ready to be pulled up and through the ‘I’-tube leaving the male connector  102  and attached bend stiffener  50  operatively mounted to the ‘I’-tube without external intervention by, for example, a subsea diver or ROV. A sequence of pulling the riser end-fitting  32  through the male connector  102  is shown in  FIGS. 11  ( a ) and ( b ). 
       Removal and Storage of End-Fitting Adapter 
       [0060]    After installation of the bend stiffener  50 , and once the riser  30  is connected to the FPSO  20 , the adapter assembly  104  may be removed from the riser end-fitting  32  for storage until it may be used again for another installation or de-installation of a bend stiffener  50 . 
         [0061]    As shown in  FIGS. 12  ( a )-( d ), the three complete locking pins  114  must be removed first to allow the primary collets  110  to return to their “active” first position. The three locking pins  114  are then replaced and disengagingly locked with the retaining grub screws  116 . In particular, the locking pins  114  are first inserted but not screwed in until the retaining grub screws  116  are replaced to lock the locking pins  114  into place. The riser end-fitting adapter  104  is then removed by simply removing bolts  108  and ring mount  106 . 
         [0062]    It is understood by the person skilled in the art that in an alternative embodiment of the present invention, the adapter assembly  104  may be an integral part of the riser  30  and/or riser end-fitting  32 , in which case it will not be removable for storage after completion of the installation. 
       Subsea De-Installation of a Bend Stiffener 
       [0063]    Referring now to  FIGS. 13  ( a )-( d ) and  14  ( a )-( d ), in order to utilize the present invention for intervention-less subsea de-installation of a bend stiffener  50 , the previously stored adapter assembly  104  is reassembled and mounted to the bottom end of the riser end-fitting  32 . In particular, locking pins  114  of the primary collets  110  are locked by retaining grub screw  116  so as to not engage with the primary collets  110 . The primary collets  110  are thus slidable within recesses  118  and urged in a radially outward direction by biasing means, such as stacked conical washers  112 . Secondary collets  120  are indexed and retained in their second position (i.e. retracted within recesses  122 ). 
         [0064]    The prepared riser end-fitting  32  and attached riser  30  are then lowered into the throughbore  130  of the male connector  102  via ‘I’-tube  60 . When engaging with the inner wall of the female connector  74 , the primary collets  110  are pushed back into the recesses  118  until engaging with the circumferential groove  128 , where the primary collets  110 . The riser end-fitting  32  is then lowered further so that the primary collets move back out of engagement with the groove  128  through the mating chamfered lower edges of the primary collets  120  and the groove  128 . An optional shoulder (not shown) arranged within the throughbore  130  may stop the decent of the riser end-fitting  32  at a predetermined position. 
         [0065]    As shown in  FIGS. 14  ( a )-( d ), when the riser end-fitting  32  is moved back up, the biasing means  112  urge the primary collets  110  back into engagement with the groove  128  so as to attach the riser end-fitting  32  to the male connector  102 . When continuing to move the riser end-fitting  32  upwards, the attached male connector  102  (and connected bend stiffener  50 ) is also moved upwards disengaging with the female latch  76 . A female connector stop (not shown) may prevent the male connector  102  to be moved to far. The female latch  76  is then retracted and the riser end-fitting  32  with attached male connector  102  and bend stiffener  50  are released from the female connector  74 , allowing the riser end-fitting  32 , male connector  102  and bend stiffener  50  to be lowered as required. 
         [0066]    The female latch  76  may be retracted manually by a subsea diver or ROV. However, in an alternative embodiment the female latch mechanism  76  may be adapted to be actuated by a suitable actuator (not shown) of the male connector when moving the riser end-fitting  32  and male connector  102  upwards within the throughbore  130 . 
         [0000]    Removal of the Riser End-Fitting from the Male Connector 
         [0067]    After completion of de-installation of the bend stiffener  50  from the ‘I’-tube  60 , the riser end-fitting  32  is removed out of engagement with the male connector  102 , as shown in  FIGS. 15  ( a ) and ( b ). 
         [0068]    In particular and if required, the male connector  102  is rotated about the riser end-fitting  32  to align the primary collets  110  with tapped holes  136  situated in the male connector  102 . A retraction tool  404  is inserted into the tapped holes  136  and screwed in to move the primary collets  110  back into their second “retracted” position. The male connector  102  may now be moved off the riser end-fitting  32 . 
         [0069]    It will be appreciated by persons skilled in the art that the above embodiment has been described by way of example only and not in any limitative sense, and that various alterations and modifications are possible without departing from the scope of the invention as defined by the appended claims.