Abstract:
A marine connector having a central core, a first shoulder disposed around at least part of the central core, a second shoulder disposed around at least part of the central core and spaced from the first shoulder and an expandable clamping member disposed around at least part of the central core and between the first and second shoulders. The first and second shoulders are relatively movable from a first distance apart, wherein the clamping member is at a first or rest width, to a second distance apart, wherein the shoulders act upon the clamping member to expand it outwardly from the central core to a second or expanded width. In use the connector may be received into a complementary female receptacle or into a length of pipe, to act as a pipeline recovery tool.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to marine connectors, especially those used in pipeline recovery systems and in mooring connectors. 
       BACKGROUND TO THE INVENTION 
       [0002]    Marine connectors come in a variety of forms. Two such fowls are mooring connectors and pipeline recovery system connectors. 
         [0003]    Mooring lines are used in a variety of applications. One such application would be the mooring of an off-shore oil drilling platform. A remotely operated underwater vehicle (“ROV”) would typically be used to install such connectors and such connectors would typically rely upon a ball and taper mechanism. These mechanisms and the connectors associated with them will typically be large, expensive and require special tooling to connect and disconnect. 
         [0004]    During pipe-laying operations a pipe-laying vessel will feed out lengths of pipe in order to connect, for example, an off-shore drilling platform with storage or processing units, either off-shore or on-shore. Pipe-laying vessels commonly, but unintentionally, lose the pipe. Further, they may have to discontinue pipe-laying due to severe weather and drop the pipe onto the seabed. Since the pipe will generally be laid upon the seabed, a recovery operation will be required to recover the pipe and continue the pipe-laying. Given the depth of water usually encountered in such laying operations, an ROV will be used to connect a pipeline recovery tool to the pipe. Such tools are typically in the form of an elongate circular cross-section body with an outer diameter co-operable with the internal diameter of the pipe to be recovered. The body is inserted into the free end of the pipe and usually a ball and taper mechanism is used to grip the pipe internally. Again, these mechanisms may be large, expensive and require special tooling to connect and disconnect. 
       SUMMARY OF THE INVENTION 
       [0005]    According to the present invention there is provided a connector comprising a central core, a first shoulder disposed around at least part of the central core, a second shoulder disposed around at least part of the central core and spaced from the first shoulder, an expandable clamping member disposed around at least part of the central core and between the first and second shoulders, wherein the first and second shoulders are relatively movable from a first distance apart, wherein the clamping member is at a first or rest width, to a second distance apart, wherein the shoulders act upon the clamping member to expand it outwardly from the core to a second or expanded width. 
         [0006]    The width may be a diameter of the clamping member, or some other suitable measure if a non-circular clamping member is used. Both first and second shoulders may both be movable, or one may be fixed and the other movable. The central core may be substantially cylindrical. The first shoulder may be disposed completely around the central core. The second shoulder may be disposed completely around the central core. The clamping member may be disposed completely around the central core. The first and/or second shoulder may be formed as an incline. The incline may be formed as a linear incline. The incline may start from a first point adjacent the central core and slope upwardly and away from the other shoulder. The shoulder may be a hollow conical frustum. The clamping member may be a split collet. The clamping member may comprise six discrete part-circular sections. The sections may be retained by at least one retainer surrounding them. The retainer may be a spring clip. There may be two such spring clips. The at least one spring clip may be seated within a groove provided around the clamping member. 
         [0007]    It will be understood that the clamping member may comprise other amounts of discrete sections and still be within the scope of the present invention. 
         [0008]    The clamping member may be in the general form or a toroid. The toroid may be a generally triangular cross-section toroid. The apex of the generally triangular cross section may be directed toward the central core. The triangular cross section may have substantially the same angle as the incline of the shoulder. A sliding fit between the two may thereby be formed. 
         [0009]    The first shoulder may be movable by a captive bolt. The second shoulder may be movable by a captive bolt. The first and second shoulders may be movable towards one another. The movement towards one another may be caused under action of the same captive bolt. 
         [0010]    A compressible bias may be employed to translate the captive bolt&#39;s action onto the first or second shoulders. 
         [0011]    An outer surface of the clamping member may be adapted to provide better grip. The outer surface may include one or more raised ridges projecting outwardly. The ridges may be provided circumferentially around the clamping member. 
         [0012]    The outer surface may also be adapted in further manners to provide better grip; for example, it may be roughened, dimpled, knurled, threaded, etc. 
         [0013]    A seal, such as an elastomeric seal, may also be provided around the central core. The first and/or second shoulders may be mounted upon a sleeve. 
         [0014]    The seal may be mounted around the sleeve. The seal may act as the compressible bias. 
     
    
     
       DETAILED DESCRIPTION OF THE INVENTION 
         [0015]    Embodiments of the invention will now be described with reference to the following drawings, in which: 
           [0016]      FIG. 1  is a perspective view of a mooring connector according to the present invention in a disengaged position; 
           [0017]      FIG. 2  is a sectional elevation of the mooring connector of  FIG. 1  disposed within a corresponding female receptacle in a disengaged position; 
           [0018]      FIG. 3  is a perspective view of the mooring connector of  FIG. 1  in an engaged position; 
           [0019]      FIG. 4  is a sectional elevation of the mooring connector of  FIG. 1  disposed within a corresponding female receptacle in an engaged position; 
           [0020]      FIG. 5  is a perspective view of a female receptacle shown in  FIGS. 2 and 4 ; 
           [0021]      FIG. 6  is a perspective view of the central core of the mooring connector of  FIG. 1 ; 
           [0022]      FIG. 7  is a perspective view of a shoulder seat of the mooring connector of  FIG. 1 ; 
           [0023]      FIG. 8  is a perspective view of a movable shoulder assembly of the mooring connector of  FIG. 1 ; 
           [0024]      FIG. 9  is a perspective view of a split collet assembly of the mooring connector of  FIG. 1 ; 
           [0025]      FIG. 10  is a perspective view of a second shoulder of the mooring connector of  FIG. 1 ; 
           [0026]      FIG. 11  is a perspective view of a nose cone of the mooring connector of Fig. 
           [0027]      FIG. 12  is a perspective view of the captive bolt of the mooring connector of  FIG. 1 ; 
           [0028]      FIG. 13  is a perspective view of a spring clip of the mooring connector of  FIG. 1 ; 
           [0029]      FIG. 14  is a perspective view of a first embodiment pipeline recovery tool according to the present invention; 
           [0030]      FIG. 15  is a sectional elevation of the pipeline recovery tool of  FIG. 14  located within a pipe; 
           [0031]      FIG. 16  is a perspective view of a second embodiment pipeline recovery tool according to the present invention; 
           [0032]      FIG. 17  is a sectional elevation of the pipeline recovery tool of  FIG. 16 ; 
           [0033]      FIG. 18  is a sectional elevation of the pipeline recovery tool of  FIG. 16  located within a pipe; 
           [0034]      FIG. 19  is a perspective view of a central core of the pipeline recovery tool of  FIG. 16 ; 
           [0035]      FIG. 20  is a perspective view of a valve body of the pipeline recovery tool of  FIG. 16 ; 
           [0036]      FIG. 21  is a perspective view of a valve handle of the pipeline recovery tool of  FIG. 16 ; 
           [0037]      FIG. 22  is a perspective view of a shoulder seat of the pipeline recovery tool of  FIG. 16 ; 
           [0038]      FIG. 23  is a perspective view of a deployment bracket of the pipeline recovery tool of  FIG. 16 ; 
           [0039]      FIG. 24  is a perspective view of a first movable shoulder of the pipeline recovery tool of  FIG. 16 ; 
           [0040]      FIG. 25  is a perspective view of an outer retaining collar of the pipeline recovery tool of  FIG. 16 ; 
           [0041]      FIG. 26  is a perspective view of a captive bolt of the pipeline recovery tool of  FIG. 16 ; 
           [0042]      FIG. 27  is a perspective view of a split collet assembly of the pipeline recovery tool of  FIG. 16 ; 
           [0043]      FIG. 28  is a perspective view of a spring clip of the pipeline recovery tool of  FIG. 16 ; 
           [0044]      FIG. 29  is a perspective view of a second movable shoulder of the pipeline recovery tool of  FIG. 16 ; 
           [0045]      FIG. 30  is a perspective view of a seal retaining ring of the pipeline recovery tool of  FIG. 16 ; 
           [0046]      FIG. 31  is a perspective view of an outer seal ring of the pipeline recovery tool of  FIG. 16 ; 
           [0047]      FIG. 32  is a perspective view of an elastomeric seal of the pipeline recovery tool of  FIG. 16 ; 
           [0048]      FIG. 33  is a perspective view of a nose cone of the pipeline recovery tool of  FIG. 16 ; and 
           [0049]      FIG. 34  is a perspective view of the pipeline recovery tool of  FIG. 16  with an ROY torque tool engaged. 
       
    
    
       [0050]    Referring to the drawings and initially to  FIG. 1 , a mooring connector  10  is depicted. The mooring connector  10  comprises a body  12 . The body  12  comprises a mandrel  14  projecting from a lug  16 . The mandrel  14  is generally cylindrical with a threaded portion  18  located at the distal end of the mandrel  14  from the lug  16 . 
         [0051]    The lug  16  comprises a circular flange portion  20  and a tongue portion  22 . The tongue portion  22  has a shackle aperture  24  machined through it, the shackle aperture  24  being disposed with an axis perpendicular to the major axis of the cylindrical mandrel  14 . In use, the shackle aperture  24  will receive a suitable shackle (not shown) and line/chain from a mooring point or object to be moored. 
         [0052]    The tongue portion  22  is machined from a cylindrical portion, with two planar faces  26 ,  28  machined perpendicularly to the plane of the circular flange portion  20 , with the shackle aperture  24  also located perpendicularly to the planar face  26 ,  28 . 
         [0053]    The rearmost portion of the tongue portion  22  is machined to form a rounded face  30 , adjacent the planar faces  26 ,  28 , and distally from the circular flange portion  20 . A captive bolt bore  32  is formed through the body of the tongue portion  22  extending from the rounded face  30  to the circular flange portion  20 . The captive bolt bore  32  extends generally parallel to the major axis of the cylindrical mandrel  14 , but offset from the shackle aperture  24 . 
         [0054]    A shoulder seat  34  attaches to the circular flange portion  20 . The shoulder seat  34  comprises a circular flange  36  with a cylindrical outer wall  38  extending from the radial edge of the circular flange  36 . The circular flange  36  attaches to the circular flange portion  20  via bolts (not shown) passing through flange apertures  36   a  on the circular flange  36  and into tapped bores  40  located on the circular flange portion  20 . The flange apertures  37  are countersunk such that bolts (not shown) do not project beyond the surface of the circular flange  36 . The shoulder seat  34  has a mandrel aperture  42  located at the centre of the circular flange  36  to allow the shoulder seat  34  to pass over the mandrel  14 . A captive bolt aperture  44  is also formed in the circular flange  36 . A plurality of vent bores  38   a  are formed through the cylindrical outer wall  38  which allow fluid (liquid or gas) from the surrounding environment to fill and drain from the hollow interior of the shoulder seat  34  defined within the cylindrical outer wall  38 . 
         [0055]    A movable shoulder  46  locates around the mandrel  14  adjacent and initially within the shoulder seat  34 . The movable shoulder  46  comprises a generally cylindrical spigot portion  48  with a pentagonal toroidal skirt  50  disposed around it. A second cylindrical portion  52  extends from the other side of the skirt  50  and located distally from the skirt  50  extending around the surface of the second cylindrical portion  52  is a seal indentation  54 . An elastomeric seal  55  situates within the seal indentation  54 . 
         [0056]    A frusto-conical shoulder  56  extends from the second cylindrical portion  52 . 
         [0057]    A mandrel bore  58  extends through the movable shoulder  46  which receives the mandrel  14 . 
         [0058]    A threaded bore  57  is provided in the spigot portion  48  adjacent and parallel to the mandrel bore  58 . The threaded bore  57  extends adjacent to the pentagonal toroidal skirt  50 . A narrower blind bore  57   a  extends from the threaded bore  57  through the second cylindrical portion  52  and partly into the frusto-conical shoulder  56 . 
         [0059]    A first vent bore  46   a  is provided through the spigot portion  48 , diametrically opposed to the threaded bore  57  and perpendicular to the mandrel bore  58 . The first vent bore  46   a  is in fluid communication with the mandrel bore  58  and the exterior of the spigot portion  48 . The first vent bore  46   a  allows fluid (liquid or gas) from the surrounding environment to fill and drain from the hollow interior of the shoulder seat  34  especially as the spigot portion  48  moves in and out of the shoulder seat  34 . 
         [0060]    A second vent bore  56   a  passes through the frusto-conical shoulder  56  perpendicular to the mandrel bore  58 . The second vent bore  56   a  intersects the blind bore  57   a.  Similarly, the second vent bore  56   a  and blind bore  57   a  allow fluid (liquid or gas) from the surrounding environment to fill and drain from the shoulder seat  34 . The various vent bores mitigate “vacuum” pressures (i.e. pressures below the surrounding environment) being created which may impede the operation of the apparatus. 
         [0061]    A second shoulder  60  and nose cone  62  are attached to the end of the mandrel  14 . The second shoulder  60  has a similar profile to the frusto-conical shoulder  56 , and comprises a frusto-conical shoulder  64  and short cylindrical section  65 . The nose cone  62  also comprises a frusto-conical nose section  66  and short cylindrical section  68 . The frusto-conical nose section  66  has a slightly steeper profile than either of the frusto-conical shoulders  56 ,  64 . 
         [0062]    The nose cone  62  attaches to the end of the mandrel  14  by a bolt  62   a  into a threaded bore  62   b  provided at the end of the mandrel  14  through its centre. A countersunk nose cone bore  62   c  passes through the centre of the end of the nose cone  62  to allow the attachment of bolt  62   a  to threaded bore  62   b.  A plurality of nose cone bores  62   d  are also provided on the nose cone to allow the insertion of corrosion inhibitor sticks. The bores  62   d  are offset from the central axis of the nose cone  62  and adjacent the countersunk nose cone bore  62   c  and are provided in a circular pattern around the countersunk nose cone bore  62   c.    
         [0063]    A female receptacle  72  is shown in  FIG. 5 . The receptacle  72  comprises a tubular socket portion  74  with a tongue portion  76 . The tubular socket portion  74  has an internal cavity  78  which is generally cylindrical in from. The side wall  80  of the tubular socket portion  74  includes a first fillet  82  at the first open end  84  of the tubular socket portion  74  and a short thinned section  80   a  of side wall  80  before transitioning through a second fillet  86  to a thicker section  80   b  of side wall  80 . The thinned section  80   a  is relatively short compared to the thicker section  80   b,  being about 20% (thinned section  80   a ) to 80% (thicker section  80   b ) of the length of the tubular socket portion  74 . Approximately 50% of the internal sidewall  88  from adjacent the second fillet  86  is threaded portion  88   a.  The internal cavity  78  terminates in a conical end section  90 . It will be noted that the angle of the first fillet  82  is complementary to the skirt  50 . 
         [0064]    The tongue portion  76  is similar to the tongue portion  22  of the body  12  comprising a bell-shaped tongue with a shackle aperture  92  extending through it. Similarly, there are two planar faces  94 ,  96  formed at either side which the shackle aperture  92  is fowled through. In use, the shackle aperture  92  will receive a suitable shackle (not shown) and line/chain from a mooring point or object to be moored. 
         [0065]    A captive bolt  33  is shown in  FIG. 12 . It comprises an elongate body  33   a  with a central flange  33   b  approximately half-way along the body  33   a.  On a first end of the body  33   a  a hexagonal head  33   c  is formed. The second end  33   d  located distally from the first end is a threaded portion  33   e.    
         [0066]    As can be seen from the Figs., the captive bolt  33  is first fed into the captive bolt bore  32  and the shoulder seat  34  is fed over the mandrel  14  and attached to the circular flange portion  20 . The captive bolt bore  32  has an initial larger diameter section portion  32   a  designed to receive the central flange  33   b.  The hexagonal head is accessible via the distal end of the captive bolt bore  32  on the tongue portion  22 . 
         [0067]    The shoulder seat  34  is then fed over the mandrel  14  with the two flanges  20 ,  36  being bolted together. The captive bolt  33  is therefore trapped within the initial larger diameter section portion  32   a  of the bore  32 , with the second end  33   d  projecting from the captive bolt aperture  44  of the shoulder seat  34 . 
         [0068]    The movable shoulder  46  is then fed over the mandrel  14  with the captive bolt  33  attaching to the threaded bore  57  on the spigot portion  48 . 
         [0069]    The second shoulder  60  and nose cone  62  are then attached as described above. 
         [0070]    A split collet  98  is positioned between the movable shoulder  46  and the second shoulder  60 . The split collet  98  comprises six collet sections  100  each substantially identical. The split collet  98  forms a generally triangular toroid shape, with the apex of the triangular cross-section being directed towards the centre of the collet  98 . The angle of the triangular shape is complementary to that of the two shoulders  46 ,  60 . Two spring clip indentations  102  are formed around the outer circumference of the collet  98 , one at either end. Two outer lips  104  faun the outer boundaries of the spring clip indentations  102 . The outer surface  106  of the split collet is ridged (or could be threaded in the alternative) for increased grip as will subsequently be described. Two spring clips  108  are seated within the spring clip indentations  102  and retain the collet sections  100  as a split collet  98 . 
         [0071]    In the initial position ( FIGS. 1 &amp; 2 ), the cylindrical spigot portion  48  of the movable shoulder  46  is located within the shoulder seat  34 . In this position, the movable shoulder  46  and second shoulder  60  are at their greatest distance apart. This may be considered a first distance apart. The split collet  98  abuts both at either end and since the two shoulders  46 ,  60  are at their greatest distance apart, the split collet  98  is at an initial or rest diameter, which is the minimum diameter of the collet  98 . As can be seen from the Figs, each collet section  100  abuts its immediate neighbours along its longitudinal edge  100   a.  It will be appreciated by the skilled addressee that the collet sections  100  need not abut each other in the initial or rest diameter. The pentagonal toroidal skirt  50  abuts the first fillet  82 . 
         [0072]    Rotating the captive bolt  33  causes the movable shoulder  46  to move along the mandrel  14  towards the second shoulder  60 . In fact, the mandrel  14  is drawn out of the female receptacle  72  by the action of the captive bolt  33 . This draws the second shoulder  60  towards the movable shoulder  46 . The split collet  98  is compressed longitudinally against the two shoulders  46 ,  60  which urge it outwardly from the mandrel  14  ( FIGS. 3 &amp; 4 ). The effective diameter of the collet  98  expands towards a second or expanded width. 
         [0073]    As can be seen from  FIG. 4 , when the mooring connector  10  is located within a female receptacle  72  and the collet is expanded by the mechanism described above, the outer surface  106  of the collet  9 R abuts and engages the threaded portion  88   a  of the side wall  80  of the female receptacle  72  creating an interference fit between the mooring connector  10  and the female receptacle  72 , thus the collet  98  acts as a clamping member, to clamp the mooring connector  10  to the female receptacle  72 . 
         [0074]    Turning to  FIGS. 14 &amp; 15 , a second embodiment of the present invention is depicted. The second embodiment is a pipeline recovery tool  200 . The pipeline recovery tool  200  shares a degree of similarity with the mooring connector  10 , and similar or identical parts will use a similar numbering system as used to describe the first embodiment mooring connector  10  except prefixed with a “ 2 ”. For example, the central mandrel of the pipeline recovery tool  200  is denoted  214 , and a collet section is denoted  2100 . 
         [0075]    The main difference is that the second shoulder  260  is not fixed relative to the mandrel  214  as in the mooring connector  10 , but may move along the mandrel  214 . 
         [0076]    The second shoulder seal  260  comprises a frusto-conical shoulder  264 , short cylindrical section  265  and a shoulder sleeve  267 . The shoulder sleeve  267  is disposed around the mandrel  214  and located distally from the first movable shoulder  246 . 
         [0077]    A second shoulder seal  202  is disposed between the nose cone  262  and the second shoulder  260 ; the second shoulder seal locating around the shoulder sleeve  267 . The nose cone  262  comprises a frusto-conical nose section  266  and short cylindrical section  268 . A cylindrical outer wall  269  projects from the short cylindrical section  268 . A recess  269   a  is thereby formed between the mandrel  214  and the cylindrical outer wall  269  which receives the shoulder sleeve  267 . The nose cone  262  attaches to the threaded portion  218  of the mandrel  214  by way of a threaded bore  263 . 
         [0078]    The skirt  250  on the movable shoulder  246  is not a pentagonal toroid, but a simple flange. 
         [0079]    The pipeline recovery tool  200  is inserted into a pipe P (see  FIG. 15 ). Skirt  250  abuts the open end of pipe P, which will have a planar form and thus the skirt  250  may abut the end without a significant gap. 
         [0080]    Captive bolt  233  is then engaged and rotated causing the mandrel  214  to be drawn out of the pipe P. The second shoulder  260  is drawn towards the movable shoulder  246 . This acts upon the split collet  298  which in turn acts upon the second movable shoulder  260  urging the sleeve  267  into the nose cone  262 . The shoulder seal  202  is compressed between the short cylindrical section  265  of the second movable shoulder  260  and the short cylindrical section  268  of the nose cone  262 . 
         [0081]    This compression mechanism expands the shoulder seal  202  radially outwardly into engagement with pipe P. Once no further compression of the shoulder seal  202  is possible, further rotation of the captive bolt  233  forces the second movable shoulder  260  to move towards the first movable shoulder  246  and the sleeve  267  out of the nose cone  262 . Movement of the second shoulder  260  may be characterized as a passive or reactive movement i.e. one which does not require its own captive bolt or other mechanism to cause movement along the mandrel  214 . 
         [0082]    The split collet  298  is then compressed between the two inwardly moving shoulders  246 ,  260  and expands radially outwardly into engagement with the pipe P. The outer “teeth” of the split collet  298  will tend to “bite” into engagement with the inner surface of the pipe P. Pipe P may then be manipulated with the apparatus. Any load to pull the tool  200  out of the pipe causes greater engagement between the collet  298  and pipe P mitigating unintentional disengagement of tool  200  and pipe P. 
         [0083]    Once pipe P has been successfully manipulated and engagement of tool  200  no longer required, the captive bolt  233  is simply rotated in the opposite direction to that described above, the above described compression mechanism is reversed, and the collet  298  contracts out of engagement with pipe P and the tool may be removed. 
         [0084]    Turning to  FIGS. 16-34 , a third embodiment of the present invention is depicted. The third embodiment is also a pipeline recovery tool  300 . The pipeline recovery tool  300  shares a degree of similarity with the pipeline recovery tool  200  and mooring connector  10 , and similar or identical parts will use a similar numbering system as used to describe the first embodiment mooring connector  10  and the pipeline recovery tool  200  except prefixed with a “3”. For example, the central mandrel of the pipeline recovery tool  300  is denoted  314 , and a collet section is denoted  3100 . 
         [0085]    The pipeline recovery tool  300  comprises a central mandrel  314  about which various components are located. The central mandrel  314  in the present embodiment is hollow and includes a mandrel bore  314   a  provided along its entire length, the mandrel bore  314   a  also penetrating into a portion of the lug  316 , approximately the depth of the circular flange portion  320 . 
         [0086]    A valve assembly  323  is provided on the lug  316  adjacent the circular flange portion  320 . The valve assembly  323  comprises a valve bore  323   a  projecting across the lug  316  intersecting and perpendicular to the mandrel bore  314   a.  The valve bore  323   a  is largely parallel to the shackle aperture  324 . 
         [0087]    A PTFE valve body  323   b  is seated within the valve bore  323   a.  The valve body  323   b  comprises a cylindrical body  323   c.  The cylindrical body  323   c  is hollow, comprising an outer cylindrical sidewall  323   d.  The first end  323   e  of the valve is open, and two valve body bores  323   f  are provided on the cylindrical sidewall  323   d . Mounting lugs  323   g  project from the second end  323   h.  The mounting lugs  323   g  are semi-circular projections and include tapped bores  323   i.    
         [0088]    A valve handle  325  attaches to the PTFE valve body  323   b.  The valve handle  325  comprises a circular mounting plate  325   a  on a first side of which projects a handle plate  325   b.  The handle plate  325   b  is used to turn the valve body  323   b.  A handle lug  325   c  projects from the second side of the handle plate  325   a  and is seated between the mounting lugs  323   g.  Two handle bores  325   d  are provided through the circular mounting plate  325   a  and allow bolts (not shown) to attach the valve handle  325  to the valve body  323   b  via the tapped bores  323   i.    
         [0089]    A docking bore  327  is formed in the lug  316  and similar to the captive bolt bore  332  extends through the lug  316  from the rounded face  330  to the circular flange portion  320 . The docking bore is located on the lug  316  opposite the captive bolt bore  332 . The docking bore  327  allows placement of a docking and torque reaction arm  504  from an ROV  500  used to manipulate and attach the pipe recovery tool  300 . 
         [0090]    Shoulder seat  334  comprises a circular flange  336  with a cylindrical outer wall  338  extending from the radial edge of the circular flange  336 . The circular flange  336  =aches to the circular flange portion  320  via bolts (not shown) passing through flange apertures  336   a  on the circular flange  336  and into tapped bores  340  located on the circular flange portion  320 . The flange apertures  337  are countersunk such that bolts (not shown) do not project beyond the surface of the circular flange  336 . The shoulder seat  334  has a mandrel aperture  342  located at the centre of the circular flange  36  to allow the shoulder seat  334  to pass over the mandrel  314 . A captive bolt aperture  344  is also formed in the circular flange  336 . It will be noted that there is no corresponding aperture for the docking bore  327 ; the shoulder seat seals the end of the docking bore  327 . A plurality of vent bores  338   a  are formed through the cylindrical outer wall  338  which allow fluid (liquid or gas) from the surrounding environment to fill and drain from the hollow interior of the shoulder seat  334  defined within the cylindrical outer wall  338 . 
         [0091]    A threaded portion  338   c  is provided at the distal end of the cylindrical outer wall  338 . A deployment bracket aperture  338   b  is provided around a portion of the cylindrical outer wall  338  adjacent the circular flange  336 . The deployment bracket aperture  338   b  is generally a slot-like aperture, being largely rectangular. 
         [0092]    The movable shoulder  346  is more elongate than movable shoulders  246  or  46 . Movable shoulder  346  comprises an initial, relatively short cylindrical section  347  attached to the first end of the spigot portion  348 . A shoulder lip  348   a  extends from the spigot portion  348  forming a spigot recess  348   b  around the short cylindrical section  347 . The threaded bore  357  that cooperates with the captive bore  333  is located on the short cylindrical section  347 . A frusto-conical section  351  extends from the spigot portion  348  with a relatively steep taper angle. A second cylindrical portion  352  extends from the frusto-conical section  351 . The length of the second cylindrical portion  352  is approximately 50% of the overall length of the movable shoulder  346 . A frusto-conical shoulder  356  extends from the second cylindrical portion  352 . The frusto-conical shoulder  356  has a shallower angle than the frusto-conical section  351  being about 5° measured from a central axis of the tool  300 . A mandrel bore  358  extends through the movable shoulder  46  which receives the mandrel  314 . 
         [0093]    An outer retaining collar  353  attaches to the shoulder seat  334 . The outer retaining collar  353  comprises a cylindrical section  353   a  and a frusto-conical section  353   b.  The cylindrical section  353   a  has a corresponding threaded portion  353   c  which is cooperable with the threaded portion  338   c  of the shoulder seat  334 . The outer retaining collar  353  is hollow and a central aperture  353   d  is provided at the termination of the frusto-conical section  353   b.  As can be seen from the Figs. the second cylindrical portion  352  of the movable shoulder  346  projects out of the central aperture  353   d  when the outer retaining collar  353  is attached to the shoulder seat  334 . The relatively short cylindrical section  347 , the spigot portion  348 , the shoulder lip  348   a,  the spigot recess  348   b  and the frusto-conical section  351  of the movable shoulder are located within the confines of the outer retaining collar  353  and shoulder seat  334  assembly. 
         [0094]    The inner diameter of the outer retaining collar  353  and shoulder seat  334  assembly is only slightly larger than the maximum exterior diameter of the movable shoulder  346 , namely the diameter of the spigot portion  348 . There is therefore a close fit between the two portions, but a sliding fit of the two relative to one another is provided. 
         [0095]    It will also be noted also from the Figs. that the interior surface of the frusto-conical section  353   b  is substantially the same as that of the frusto-conical section  351  and that the longitudinal space created within the outer retaining collar  353  and shoulder seat  334  assembly is sufficient to enable the movable shoulder  346  to longitudinally traverse the mandrel  314  from a first, or fully retracted position, where the short cylindrical section  347  abuts the shoulder seat  334 , to a second, or fully extended position, where the frusto-conical section  351  abuts the interior surface of the frusto-conical section  353   b.    
         [0096]    A deployment bracket  339  is attached to the outer retaining collar  353  and shoulder seat  334  assembly via the deployment bracket aperture  338   b.  Deployment bracket  339  comprises an exterior plate  339   a,  which situates on the exterior surface of the outer retaining collar  353  and shoulder seat  334  assembly, and a deployment bracket lug  339   b.    
         [0097]    The exterior plate  339   a  is a generally rectangular plate, with chamfered corners  339   c  on the edge of the plate  339   a  located distally from the edge which in use is proximal with the outer retaining collar  353  and shoulder seat  334  assembly. Three deployment bracket apertures  339   d  for manipulating the deployment bracket  339  and therefore tool  300  are formed through the plate  339   a  adjacent the edge with the chamfered corners  339   c.    
         [0098]    The deployment bracket lug  339   b  is joined and projects from the edge of the plate  339   a  which in use is proximal with the outer retaining collar  353  and shoulder seat  334  assembly, distally from the chamfered corners  339   c  and apertures  339   d.  The distal end  339   e  of the bracket lug  339   b  has a curved edge, which matches the curvature of the relatively short cylindrical section  347 . Two curved, uniform indentations  339   f  follow the edge, creating two lips  339   g  at the curved edge. The upper edges of the bracket lug  339   b  are filleted. 
         [0099]    As can be seen from the Figs, the deployment bracket lug  339   b  extends into the outer retaining collar  353  and shoulder seat  334  assembly via the deployment bracket aperture  338   b.  The lips  339   g  are seated within a chamfer of the deployment bracket aperture on a first side, and within the spigot recess  348   b  on a second side. When the movable shoulder  346  is in the first, or fully retracted position, an interference fit is formed which retains the deployment bracket lug  339   b  to the tool  300 . 
         [0100]    The split collet  398  comprises six collet sections  3100  each substantially identical. The split collet  398  foams a generally triangular toroid shape, with the apex of the triangular cross-section being directed towards the centre of the collet  398 . 
         [0101]    The triangular profile in the present embodiment is irregular rather than generally isosceles. Two spring clip indentations  3102  are formed around the outer circumference of the collet  398 , the first  3102   a  formed approximately 20% of the length from a first end  398   a  of the collet  398  and the second  3102   b  approximately 60% of the length from the first end  398   a  or 40% from a second end  398   b  of the collet  398 . Two spring clips  3108  are seated within the spring clip indentations  3102  and retain the collet sections  3100  as a split collet  398 . 
         [0102]    The ridged outer surface portion  3106  is offset towards the second end  398   b  of the collet  398  i.e. at a distal end of the collet  398  away from the movable shoulder  346  and towards the nose cone  362 . 
         [0103]    Second movable shoulder  360  comprises two separate parts: a frusto-conical shoulder section  360   a  and a seal retaining ring sleeve  360   b.  The frusto-conical shoulder section  360   a  is a conical frustum with a taper angle being about 5° measured from a central axis of the tool  300 . The seal retaining ring sleeve  360   b  comprises a cylindrical flange  360   c  having an outer diameter substantially equal to that of the greatest diameter of the conical frustum, and a sleeve portion  367  having an outer diameter substantially equal to that of the smallest diameter of the conical frustum. 
         [0104]    The cylindrical flange  360   c  is placed adjacent the greatest diameter of the conical frustum of the frusto-conical shoulder section  360   a.  An elastomeric seal  302  is placed over the sleeve portion  367 . 
         [0105]    An outer seal ring  369  is placed over the mandrel adjacent the elastomeric seal  302  and sleeve portion  367 . The outer seal ring  369  is generally a rectangular toroid with two inner flanges  369   a,    369   b  at the distal side from the elastomeric seal  302  and sleeve portion  367 . An O-ring/PTFE seal  369   e  is placed in a recess  369   c  disposed between the two inner flanges  369   a,    369   b.  The inner diameter of the outer sleeve ring  369  is sufficient to enable it to pass over the sleeve portion  367 . The inner diameter of the inner flanges  369   a,    369   b  are complementary to the outer diameter of the mandrel  314  thus ensuring proper placement. A recess  369   d  is foamed between the sleeve portion  367  and inner flange  369   a.  An O-ring/PTFE seal  369   f  is placed within the recess  369   d.    
         [0106]    The nose cone  362  also comprises a frusto-conical nose section  366  and cylindrical section  368 . The frusto-conical nose section  366  has a steeper profile than either of the frusto-conical shoulders  356 ,  364 . The cylindrical section  368  is hollow and has an inner threading  368   a  that is complementary with the threaded portion  318  of the mandrel  314 . The frusto-conical nose section  366  is also hollow with an inner bore  366   a  and aperture  366   b.  Thus, when the tool  300  is inserted into the pipe P a fluid path is formed from the interior of pipe P through the mandrel bore  314   a  and on to the valve assembly  323 . Nose cone  362  also functions as a PIG-catcher assembly. 
         [0107]    In use, the tool  300  is lowered near to the end of pipe P using a line (not shown) attached to the deployment bracket  339 . A shackle (not shown) on the end of this line (not shown) is connected to the most appropriate aperture  339   d  as judged by the user. An ROV  500  guides the tool  300  into the pipe P. A torque tool  502  on the ROV  500  engages with the captive bolt  333  and a torque reaction arm  504  is seated within the docking bore  327 . The torque tool  502  rotates the captive bolt  333 . 
         [0108]    Rotation of the captive bolt  333  causes the first movable shoulder  346  to traverse the mandrel  314  away from the shoulder seat  334 . Again, the mandrel  314  is effectively being withdrawn from the pipe P. This causes the disengagement of the interference fit that retains the deployment bracket  339 , thereby releasing the line. 
         [0109]    The frusto-conical shoulder  356  acts upon the split collet  398  which in turn acts upon the second movable shoulder  360  pushing the sleeve  367  into the outer seal ring  369 . The shoulder seal  302  is therefore compressed. 
         [0110]    This compression mechanism expands the shoulder seal  302  radially outwardly into engagement with pipe P. Once no further compression of the shoulder seal  302  is possible, further rotation of the captive bolt  333  forces the second movable shoulder  360  to move towards the first movable shoulder  346  and the sleeve  367  out of the outer seal ring  369 . Movement of the second shoulder  360  may be characterized as a passive or reactive movement i.e. one which does not require its own captive bolt or other mechanism to cause movement along the mandrel  314 . 
         [0111]    The split collet  398  is then compressed between the two relatively inwardly moving shoulders  346 ,  360  and expands radially outwardly into engagement with the pipe P. Pipe P may then be manipulated with the apparatus. The outer “teeth” of the split collet  398  will tend to “bite” into engagement with the inner surface of the pipe P. Pipe P may then be manipulated with the apparatus. Any load to pull the tool  300  out of the pipe causes greater engagement between the collet  398  and pipe P mitigating unintentional disengagement of tool  300  and pipe P. Seal  302  provides a watertight seal against pipe P. 
         [0112]    The valve assembly  327  may then be moved to its open position and the pipe P may be dewatered. This is normally accomplished by pumping a dewatering PIG into the pipe P. The nose cone  362  is adapted to receive the PIG and allow the dewatering operation to take place. The nose cone  362  prevents the PIG from moving back along the pipe P. 
         [0113]    The ROV  500  will shut the valve assembly  327  once dewatering is complete, and the tool  300  may then be used to manipulate pipe P. 
         [0114]    Once pipe P has been successfully manipulated and engagement of tool  300  no longer required, the captive bolt  333  is simply rotated in the opposite direction to that described above, the above described compression mechanism is reversed, and the collet  398  contracts out of engagement with pipe P and the tool may be removed. 
         [0115]    Modifications and improvements may be undertaken to the above described embodiments without departing from the scope of the present invention. 
         [0116]    For example, although a shoulder angle of 5° is mentioned for the third embodiment, this angle may be varied to any suitable degree. A range of 3° to 10° may be preferable.