WO2021219970A1

WO2021219970A1 - Method and apparatus for installing a cofferdam, e.g. against the hull of a ship

Info

Publication number: WO2021219970A1
Application number: PCT/GB2020/051063
Authority: WO
Inventors: David Michael Mortlock
Original assignee: E M & I (Maritime) Limited
Priority date: 2020-04-30
Filing date: 2020-04-30
Publication date: 2021-11-04
Also published as: BR112022022022A2; EP4143081A1

Abstract

A cofferdam (110) is guided and installed against a submerged wall (2) of a structure (1) by one or more flexible lines (50). Each line is retracted, via an opening (7) formed in the wall (2), by a line puller (20) mounted inside an interior space (4) of the structure (1) to pull the cofferdam against the wall (2). A connection body (10) is sealingly fixed to the dry side (6) of the wall (2) to enclose the opening (7), and a pressure barrier (21) is sealingly connected to the connection body (10) to exclude water from the interior space 4 during operation of the line puller (20). The line puller (20) may be configured as a winch assembly with a casing forming the pressure barrier (21).

Description

Method and apparatus for installing a cofferdam, e.g. against the hull of a ship

This invention relates to cofferdams for use in forming a temporary dry cavity against a submerged wall, such as a ship's hull, and in particular to methods for installing the cofferdam in its use position.

In this specification, a cofferdam means an enclosure with an open part configured to sealingly engage a submerged wall so as to define a cavity between the enclosure and the wall. Such cofferdams may be used for example to repair a damaged region on the hull of a ship without the need for dry docking.

In a typical procedure, a diver is sent down to weld threaded studs onto the hull plating and then to attach the cofferdam to the bolts. The stud bolts are removed by the diver on completion of the repair. In some cases the cofferdam is welded directly to the external hull plating by a diver. However, underwater welding can cause localised cracking of the hull due to the rapid cooling of the weld.

Once engaged against the submerged hull, water may be pumped or drained out of the cavity so that work can be done on the exposed hull. The pressure of the water on the outside of the cofferdam helps to maintain the cofferdam sealingly in position against the hull to exclude water from the dry cavity. However, if studs are not welded to the hull before placing the cofferdam, it can be difficult to position the cofferdam in the correct location and keep it there while it is connected to the hull, e.g. by pumping out the water so as to energise the seal.

The present invention provides in various aspects, an apparatus and a method for installing a cofferdam on a wet side of a submerged wall of a structure, and an installation including the structure and the apparatus, as defined in the claims. The apparatus includes a connection body defining an aperture, which is sealingly fixed to the dry side of the submerged wall to surround an opening formed through the wall in fluid communication with the aperture. The apparatus further includes a flexible line, and a line puller which is mounted in an interior space of the structure and operated to retract the line through the opening and the aperture. A line puller pressure barrier is sealingly connected to the connection body to prevent water from flowing through the opening and the aperture into the interior space during operation of the line puller. The line is connected to the cofferdam to pull the cofferdam against the wet side of the wall when the line is retracted. After sealingly engaging the cofferdam against the wet side of the wall, water is removed from the temporary cavity defined between the cofferdam and the wall. Further in accordance with the method, a pressure barrier is sealing connected to the connection body to prevent water from flowing through the opening and the aperture into the interior space while forming the opening.

By carefully positioning the connection body, optionally two or more such connection bodies on the dry side of the wall, each in a position corresponding to the point of attachment of the respective line to the cofferdam, the cofferdam may easily be guided to the correct position and then urged against the hull to form a seal, working from inside the ship or other structure. Optionally, each line may be connected to an alignment pin which extends from the cofferdam and is received in the respective opening and aperture to further ensure that the cofferdam is located and retained in the desired position.

Further features and advantages will be appreciated from the illustrative embodiment of the invention which will now be described, purely by way of example and without limitation to the scope of the claims, and with reference to the accompanying drawings, in which:

Fig. 1 shows parts of an apparatus in the form of a kit of parts in accordance with a first embodiment, including a plug 90 shown in both side and end view, and a connection body 10 shown in both side and end view and in longitudinal section taken at I - 1 of Fig. 1;

Fig. 2 shows a winch assembly forming a further part of the apparatus;

Fig. 3 is a top view of the winch assembly with the window removed;

Fig. 4 is a top view of the winch assembly with the window in place;

Fig. 5 is a section through the winch housing at V - V of Fig. 3;

Fig. 6 shows a first step in a method in accordance with the first embodiment, wherein the connection body of the apparatus is welded in its use position to the dry side of a ship's hull;

Fig. 7 shows the valve attached to the connection body;

Fig. 8 shows the penetrator tool in use to cut the opening;

Fig. 9 shows the finished installation with the valve closed after removing the penetrator tool;

Fig. 10 shows the connection body sealed with a plug and a cap in a final step of the method after carrying out the repair and removing the cofferdam;

Fig. 11 shows the winch assembly connected to the valve after forming the opening;

Fig. 12 shows the float ejected from the winch assembly;

Fig. 13 shows the apparatus including two connection bodies and winch assemblies in a use position, after recovering the floats and attaching the lines to the alignment pins of the cofferdam;

Fig. 14 shows the cofferdam engaged with the hull in its use position after retracting the lines;

Fig. 15 shows one of the alignment pins received through the opening into the connection body in the use position of the cofferdam;

Fig. 16 shows the plug deployment tool in use to seal the connection body with a plug; and

Fig. 17 shows the installation comprising two connection bodies sealed with plugs and caps as shown in Fig. 10. Reference numerals appearing in more than one of the figures indicate the same or corresponding parts in each of them.

Referring to Figs. 1 - 5, the apparatus includes at least one connection body 10 defining an aperture 12, and at least one line puller 20 which, as shown, may be formed as a winch assembly. The or each line puller is provided with a respective line puller pressure barrier 21, which, as illustrated, may form a casing of the line puller or winch assembly. The apparatus further includes a cofferdam 110 and at least one flexible line 50; each line connects the cofferdam to a respective line puller, as illustrated in Fig. 13.

Preferably the apparatus further includes, for each connection body 10, a respective valve 60 which is operable to selectively open and close a valve orifice 61, e.g. by translating, rotating or otherwise moving a valve element 62 which is received in the valve body 63. In the use position of the valve, the valve orifice 61 is sealingly connected in fluid communication with the opening 7 via the flowpath 11 of the connection body 10. The valve may be configured as a gate valve, with the valve element configured as a sliding gate in the valve body. The valve 60 is connected sealingly to the connection body 10 and serves to connect the line puller, e.g. winch assembly 20 to the connection body 10. The valve 60 may be sealingly and releasably connected to the connection body, e.g. via bolted flanges as shown, or by any other suitable fixing arrangement as known in the art.

As shown in Fig. 1, the apparatus may be provided in the form of a kit of parts, optionally including various further components such as a penetrator tool 70 and/or a plug deployment tool 80, which may be connected to the connection body 10, preferably interchangeably, and preferably via the valve 60 - which is to say, the valve 60 is preferably interposed between the connection body 10 and the penetrator tool or plug deployment tool. A respective plug 90 and/or cap 100 may be sealingly engagable with each respective connection body 10 to exclude water from the connection body, which may thus form a permanent installation after completing the repair and removing the cofferdam. The plug and/or cap may be releasable so that the connection body can be used again with the rest of the apparatus for a future repair.

The connection body 10 defines a flowpath 11 which opens through apertures 12 and 13 at opposite, outer and inner ends of the connection body. By the outer end is meant that end of the connection body that is connected in use to the submerged wall 2 of the structure 1.

The connection body 10 may be internally threaded 16, e.g. at the inner end aperture 13 as shown, to receive an externally threaded plug 90, and may include a generally cylindrical wall 14 that surrounds the flowpath 11. A flange 15 may be formed at the inner end of the wall 14 for connecting components of the apparatus to the connection body 10. Such components may include a cap 100 which is bolted to the flange; alternatively or additionally, the inner end of the wall 14 could be externally threaded to receive an internally threaded cap.

These and other features of the connection body and various optional components of the apparatus may be generally as taught in WO2015/079199 A1 to the present applicant.

Referring to Fig. 13, the structure 1 may be a floating structure such as a ship which is supported in a body of water 3, e.g. the sea. The submerged wall 2 may form the hull of the ship, and excludes the body of water 3 on the wet side 5 of the wall from the interior space 4 within the structure. The interior space 4 is bounded by a dry side 6 of the wall opposite its wet side 5.

Referring to Fig. 4, each connection body 10 is fixed sealingly to the dry side 6 of the wall 2 in the desired use position to form an installation. As shown in Fig. 13, the installation may include two or more connection bodies 10 which are sealingly fixed in spaced relation to the dry side 6 of the wall 2 for use with two or more respective line pullers 20 as further explained below. The or each connection body 10 may be made from steel or other metal and may be permanently connected, e.g. welded to the wall 2, which may be made from steel plate. Other means of connection may be employed, for example, brazing or mechanical fastening.

After fixing each connection body 10, it may be tested for pressure tightness, for example, as described in WO2015/079199 Al. A valve 60 may then be connected to the connection body 10 (Fig. 7).

Referring to Fig. 1 and Fig. 8, the penetrator tool 70 includes a cutter 71 mounted on a tool body 72 which is sealingly and releasably connected to the valve 60, e.g. via a bolted flange as shown. The tool 70 is operable in the use position of the connection body to advance and retract the cutter 71 through the open valve orifice 61 and the flowpath 11 and aperture 12 of the connection body 10.

The cutter 71 may be mounted on a driveshaft 73 that can be engaged by a drive tool 74 to drive the cutter in rotation. The driveshaft 73 may be rotatably mounted in an axially movable outer shaft 75 which is rotated by a handle 76 to advance the cutter 71 as it rotates.

After advancing the cutter 71 to engage the wall 2 the cutter 71 is operated (driven in rotation and progressively further advanced) within the connection body 10 to cut an opening 7 through the wall 2, as shown in Fig. 8. The detached coupon may be captured and retracted with the cutter.

The opening 7 is formed within the aperture 12 of the connection body so that it is surrounded by the connection body 10. That is to say, the opening 7 is in fluid communication with the aperture 12 and flowpath 11 so that it opens into the connection body 10 at the aperture 12, and forms a flowpath opening through, and extending between, the wet and dry sides of the wall 2. The flowpath 11 of the connection body is in fluid communication with the body of water 3 via the opening 7 and aperture 12, while the connection body 10 by its sealing connection to the wall 2 retains the fluid pressure of the water within the flowpath 11.

The penetrator tool 70 further includes a pressure barrier, which as shown may be formed by the tool body 72 which sealingly engages the shaft assembly 73, 74. The pressure barrier is sealing connected in use to the connection body 10, preferably via the valve 60, and is configured to prevent water from flowing from the body of water 3, through the opening 7 and the aperture 12 into the interior space 4 during operation of the penetrator tool to form the opening 7.

After forming the opening 7, the cutter 71 is withdrawn on the shaft assembly 73, 74 and then the valve 60 is closed to retain the fluid pressure of the body of water 3 before removing the penetrator tool 70 from the valve 60 (Fig. 9).

In its use position, each connection body 10 thus surrounds a respective opening 7 formed through the wall 2 in fluid communication with the respective aperture 12, so that by providing two or more connection bodies 10, two or more line pullers 20 can be mounted in the interior space 4.

Referring to Fig. 13, the apparatus further includes a cofferdam 110 which is sealingly engagable in use against the wet side 5 of the submerged wall 2 to define, and exclude water from, a temporary cavity 111 between the cofferdam 110 and the wet side 5 of the wall.

The cofferdam 110 defines an enclosure with an open side 112 surrounded by a sealing surface 113 that engages the wall 2 in use. The sealing surface may comprise a resilient sealing material, e.g. rubber. The enclosure is configured to resist external fluid pressure when drained of water so that the dry cavity 111 provides a working space within which the wet side 5 of the wall is exposed so that damage to the wall 2 can be repaired. The cofferdam 110 may be supported buoyantly or via a cable 114 while it is pulled and/or lowered into position in the body of water 3 alongside the structure 1. A hose 115 may be provided for extracting water from the cavity 111 or re-filling the cavity 111 with water after the work is finished.

In order to obtain a satisfactory seal on an uneven hull surface, the sealing surface 113 may be formed on an assembly of two bodies of resilient sealing material (e.g. elastomer, e.g. rubber or neoprene) of different hardnesses. It is found that a particularly effective seal may be obtained by arranging a relatively harder one of the bodies between the wall of the cofferdam and the softer one of the bodies, so that the softer one of the bodies forms the sealing surface 113 which engages the hull of the ship or other structure. The two bodies may be assembled together by adhesive.

One or more alignment pins 116 may extend from the cofferdam. A distal end of each alignment pin 116 is attached or attachable to a distal end of a respective flexible line 50. This connection could be provided by a connector at the distal end of the alignment pin, which could be a solid pin; alternatively for example, if the alignment pin is tubular, then the connection to the distal end could be accomplished by passing the distal end (i.e. the distal end portion) of the line 50 through the tublar alignment pin and then connecting the line to the cofferdam inwardly of the pin 116. Each pin 116 may be rigidly fixed to the cofferdam 110. Where as shown more than one pin 116 is provided, the pins 116 may extend in parallel relation.

Each alignment pin 116 may extend outwardly away from the open side 112 of the cofferdam 110, beyond a plane (which may be flat or curved, e.g. as shown) in which the sealing surface 113 lies. The plane is defined by the wet side 5 of the wall 2 in the use position of the cofferdam 110; in use, each pin 116 may thus extend through a respective opening 7 and into the aperture 12 and flowpath 11 of the respective connection body 10 as shown in Figs. 14 and 15 and further described below. Each alignment pin 116 may be connected to the cofferdam 110 within the cavity 111 so that it extends outwardly through the opening or open side 112 of the cofferdam. In this configuration, the flowpath 11 of each connection body 10 will communicate in use with the cavity 111. Alternatively or additionally, one or more alignment pins 116 could be arranged around the cofferdam outside the cavity 111, each to be received in a connection body 10 which remains in fluid communication with the body of water 3 outside the cavity 111 in the use position of the cofferdam. Referring again to Fig. 13, each line puller pressure barrier 21 is sealingly, and preferably releasably connected in use to a respective one of the connection bodies 10, preferably via the respective valve 60. Each line puller 20 is mounted in the interior space 4, which may be accomplished by supporting the line puller 20 on the respective line puller pressure barrier 21 which in turn is mounted on the connection body 10, preferably via the valve 60.

The valve orifice 61 can then be opened so that the line 50 can be passed through the opening 7 and the aperture 12 and through the valve orifice 61 to connect the cofferdam 110 to the line puller 20. The line puller 20 can then be operated to retract the line through the opening 7 and the aperture 12 via the valve orifice 61.

The line puller pressure barrier retains (withstands) fluid pressure from the body of water 3 outside the structure to prevent water from flowing through the opening 7 and the aperture 12 into the interior space 4 during operation of the respective line puller 20.

Thus, in use, each line 50 extends from the respective line puller 20 to the cofferdam 110, through a respective opening 7, through the flowpath 11 and apertures 12, 13 of the respective one of the connection bodies 10, and (where a valve 60 is provided) also through the open valve orifice 61. The distal end of the line 50 is connected to the cofferdam 110, optionally at the distal end of the respective alignment pin 116 as shown. Where two or more line pullers are used, their respective lines 50 are connected at respective, spaced locations on the cofferdam 110 corresponding to the positions of the respective connection bodies 10 on the wall 2. The connection bodies may be spaced apart vertically and/or horizontally so as to accurately locate the cofferdam 110 in its use position.

Each line puller 20 is operated in its use position to retract the respective line 50 through the respective opening 7 and the aperture 12 to pull the cofferdam towards and against the wet side 5 of the wall 2, as shown in Figs. 13 and 14. The pulling force of the lines 50 sealingly engages the cofferdam 110 against the wet side 5 of the wall 2 to define, and exclude water from, the temporary cavity 111 between the cofferdam 110 and the wet side 5 of the wall 2.

Once the cofferdam is in its use position, the water can be removed from the temporary cavity 111 to leave it dry as shown in Fig. 14. The water may be drained from the cavity 111 via a respective one of the connection bodies 10 (e.g. via valve 60) or extracted through the hose 115. In use, after the cofferdam has been drained of water, a limited volume of water (e.g. a few litres per hour) may continue to flow past the seal into the cofferdam, but may be drained away via the lowermost connection body (e.g. via valve 60) to keep the cofferdam dry.

Once the cofferdam 110 is drained of water, the damaged region of the wall 2 (e.g. the ship's hull) can be cut out to provide an opening through which a worker can access the cavity 111 from inside the structure 1 to work on the wet side 5 of the wall 2. The external cut edges formed during installation of the pressure ports can then be made good and the damaged area of the hull prepared for the repair. Finally, the repair plate can be inserted into the aperture and welded into place from inside the interior space 4 of the structure, e.g. inside the ship. Alternatively the cavity 111 could be accessed from outside the structure 1, e.g. via an external access passage, as known in the art. Referring now to Figs. 2 - 5, the line puller 20 may include a spool 22 on which the line 50 is stored when retracted. The spool 22 including the retracted line may be enclosed within the line puller pressure barrier 21. Thus, the line puller 20 may be configured as shown as a winch assembly 20 wherein the spool 22 is configured as a winch drum and the line puller pressure barrier 21 forms the pressure tight, outer casing of the assembly. The outer casing may include a connection flange 33 to form a pressure tight, bolted connection to the valve 60 as shown.

The line puller pressure barrier 21 may include a transparent window 23 for observing the operation of the line puller 20. In use, fluid pressure from the body of water 3 will cause a quantity of water 8 to flow through the opening 7, connection body 10 and valve 60 into the outer casing after the valve 60 is opened, until the outer casing is full; thus, once the cofferdam 110 is in position, the window 23 may be used to check when the cavity 111 has been emptied of water. As shown, the spool 22 may be configured to be driven in rotation mechanically from outside the line puller pressure barrier 21, e.g. by a manual crank handle 24 via a driveshaft 25 and geartrain 26 as shown. The driveshaft 25 passes through a pressure seal 27 where it enters the outer casing. The line puller 20 may include a guide mechanism 28 for guiding the line 50 in an axial direction of the spool 22 during rotation of the spool. The guide mechanism 28 may be operable mechanically from outside the line puller pressure barrier 21, e.g. by a rotating shaft 29 which passes through a pressure seal 30 where it enters the casing. The shaft 29 may rotate a leadscrew 31 which in turn drives a captive guide block 32 axially along the spool. The line 50 passes through the guide block so that by moving the guide block as the spool rotates, the line 50 can be wound evenly onto the spool.

Referring also to Figs. 11 and 12, the line puller 20 may include a float 40 and a float deployment mechanism, which may be configured as an axially displaceable rod 41.

The float 40 is preferably arranged to fit within and move slidingly along inside the flowpath defined by the axially connected opening 7, connection body 10, valve orifice 61 and line puller pressure barrier 21; the line puller pressure barrier may include a float cavity 42 within which the float 40 is received as shown in Fig. 11 before deployment.

The float 40 is attached to a distal end (i.e. distal end portion) of the line 50. For this purpose the float 40 may be formed in two halves which are fixed together to enclose the line 50 in-between them before connecting the line puller 20 and the line puller pressure barrier 21 in their use position.

The float deployment mechanism is then operated, e.g. by pushing in the rod 41 as shown in Fig. 12, to advance the float 40 and the distal end of the line 50 from the interior space 4, through the opening 7 and the flowpath 11 and apertures 12, 13 of the connection body 10, and via the valve orifice 61 if provided, into the body of water 3 on the wet side 5 of the wall 2.

In this position the float 40 may be captured and brought to the surface, e.g. by an underwater, remotely operated vehicle (ROV). Alternatively, the float 40 could be configured to draw the line buoyantly to the surface as the line 50 is payed out by operation of the line puller. To assist this process, the line 50 could include a lighter, lead line (i.e. leading line) which is connected to the distal end of the main line, which in turn will be connected to the cofferdam 110 after the float is recovered at the surface of the body of water 3 and the main line drawn up after the lead line. The main line could be a steel cable or could be made from lighter fibres, in which case a lead line may not be required.

The line puller pressure barrier 21 is configured to prevent water from flowing through the opening 7 and the aperture 12, via the connection body 10 into the interior space 4 during operation of the float deployment mechanism.

Referring to Figs. 14 and 15, each line 50 is retracted to pull the alignment pin 116 into the corresponding opening 7 and the aperture 12. In the use position of the cofferdam 110, each alignment pin 116 is thus received in the respective opening 7 and the aperture 12, within the flowpath 11 of the connection body 10, to locate the cofferdam 110 on the wet side 5 of the wall 2. The line puller 20, e.g. spool or winch mechanism, may be locked to retain the alignment pin 116 while the cofferdam is in use.

The openings 7 provide predefined locations for the attachment points of the lines 50, so that by arranging the connection bodies 10 in a pattern corresponding to the attachment points of the lines 50 to the cofferdam, the cofferdam 110 can be readily located on the wet side of the wall without diver assistance. The alignment pins 116 provide a firmer connection which further ensures the correct location of the cofferdam 110 and further resists forces, e.g. a net buoyancy force, that may be applied to the cofferdam in the plane of the wall 2.

After completing the repair, the cofferdam may be released from the wet side 5 of the wall 2, e.g. by unlocking the line puller 20 and paying out the line 50. The float deployment mechanism may be adapted to be operable to urge the alignment pins 116 out of the openings 7. The cofferdam 110 can the be recovered to surface, e.g. on the cable 114, before detaching the line 50 from the cofferdam (Fig. 17).

The line 50 is then removed from the opening 7, the flowpath 11 and apertures 12, 13 of the connection body, and the valve orifice 61, optionally by retracting it fully into the line puller 20. The valve 60 can then be operated to close the valve orifice 61 before removing the line puller pressure barrier 21 from the valve 60. The flowpath 11 and apertures 12, 13 of the connection body 10 can then be sealed with the plug 90.

Referring to Fig. 16 and Fig. 1, the plug deployment tool 80 includes a body 81 which is sealingly and releasably connected to the valve 60 before opening the valve orifice 61 and operating the tool to advance the plug 90 through the valve orifice 61 and to sealingly engage the plug 90 with the connection body 10.

The plug deployment tool 80 may be generally as described in WO2015/079199 Al, including an inner shaft 82 which is rotatably received in an outer shaft 85 having a plate 86 with studs 87 which are received in holes 92 in the plug. The inner shaft 82 is rotated by a knob 83 to engage a threaded stud 84 in a corresponding threaded hole 91 in the plug 90 to retain the plug 90 in engagement with the studs 87. The shaft assembly 82, 85 is pushed axially through the body 81 to engage the threaded plug 90 via the aperture 13 in the flowpath 11 of the connection body 10 before rotating the outer shaft 85 using its handle 88 to screw the plug 90 into the female thread 16 of the connection body 10.

The plug deployment tool 80 includes a pressure barrier, which conveniently may be formed by the tool body 81 which sealingly retains the shaft assembly 82, 85. The pressure barrier is configured to prevent water from flowing through the opening 7 and the flowpath 11 and apertures 12, 13 of the connection body 10, into the interior space 4 during operation of the plug deployment tool 80.

The plug 90 may include a sacrificial anode 93 which extends into the connection body 10 and/or opening 7 to protect the fixed assembly from corrosion. Although the anode 93 is relatively short as illustrated in Fig. 10, it could extend through the opening 7 so that an end face of the anode 93 lies in or proximate the plane of the wet side 5 of the wall 2, to provide protection to the cut surfaces of the wall 2 in the opening 7. The plug 90 could be engaged in a thread at the outer end of the connection body 10 rather than its inner end as shown.

After sealing each connection body 10 with a respective plug 90, the valve 60 may be removed. A respective cap 100 may then be fixed sealingly to each respective connection body 10 to cover the plug, e.g. by bolting the cap to the flange 15, to provide a safe and compact installation as shown in Fig. 17.

In summary, a cofferdam 110 is guided and installed against a submerged wall 2 of a structure 1 by one or more flexible lines 50. Each line is retracted, via an opening 7 formed in the wall 2, by a line puller 20 mounted inside an interior space 4 of the structure 1 to pull the cofferdam against the wall 2. A connection body 10 is sealingly fixed to the dry side 6 of the wall 2 to enclose the opening 7, and a pressure barrier 21 is sealingly connected to the connection body 10 to exclude water from the interior space 4 during operation of the line puller 20. The line puller 20 may be configured as a winch assembly with a casing forming the pressure barrier 21.

In alternative embodiments, instead of separate parts that are releasably connected together, two or more of the apparatus elements could be integrated together as a permanent assembly. For example, the connection body could be permanently associated with a valve body for receiving a moving valve element.

The line puller pressure barrier could be configured other than as a casing of the line puller; for example, it could form a fluid pressure seal through which the line moves slidingly in use.

The line puller, e.g. the spool, could be driven by a motor, e.g. an electric motor, rather than manually. The spool and guide mechanism could be geared together so that they are driven in rotation simultaneously by a common drive mechanism. A smooth liner or guide could be provided to extend into the opening 7, to line the whole opening or just the upper part of the opening 7, so as to assist the line 50 to move through the opening without becoming caught on a sharp outer edge of the opening. The liner or guide could be advanced from the line puller 20 into the opening 7 and locked in that position, and then subsequently retracted again in a similar way to the rod 41, perhaps after the lead line has been deployed from the spool. It could be arranged behind the float to function as the float deployment mechanism to push the float 40 out through the opening 7 instead of the rod 41. The alignment pin 116 could be arranged to pass into the liner or guide or to displace it inwardly as the cofferdam moves into its use position.

Although it is preferred to provide a valve 60 to retain fluid pressure while removing or attaching the different components of the apparatus, it is conceivable that the apparatus could be provided as a permanent assembly, or that the opening 7 could be temporarily closed in another way, e.g. by means of a plug inserted from the wet side 5 of the wall 2.

Many further adaptations are possible within the scope of the claims. In the claims, reference numerals are provided in parentheses, purely for ease of reference, and are not to be construed as limiting features.

Claims

1. An apparatus for installing a cofferdam (110) on a wet side (5) of a submerged wall (2) that excludes a body of water (3) from an interior space (4) of a structure (1), the interior space (4) being bounded by a dry side (6) of the wall (2) opposite the wet side (5); the apparatus including: a cofferdam (110), the cofferdam being sealingly engagable in use against the wet side (5) of the wall (2) to define, and exclude water from, a temporary cavity (111) between the cofferdam (110) and the wet side (5) of the wall (2); a connection body (10) defining an aperture (12), the connection body (10) being sealingly fixable to the dry side (6) of the wall (2) in a use position, to surround an opening (7) formed through the wall (2) in fluid communication with the aperture (12); a flexible line (50); a line puller (20) operable, when mounted in use in the interior space (4), to retract the line (50) through the opening (7) and the aperture (12) in the use position of the connection body (10); and a line puller pressure barrier (21), the line puller pressure barrier (21) being sealingly connected in use to the connection body (10) to prevent water from flowing through the opening (7) and the aperture (12) into the interior space (4) during operation of the line puller (20); the line (50) being connected in use to the cofferdam (110) to pull the cofferdam against the wet side (5) of the wall (2) when the line (50) is retracted. 2. An apparatus according to claim 1, including a float (40) and a float deployment mechanism (41); the float (40) being attached in use to a distal end of the line (50); the float deployment mechanism (41) being operable in use to advance the float (40) and the distal end of the line (50) from the interior space (4) through the opening (7) and the aperture (12) into the body of water (3) on the wet side (5) of the wall (2); the line puller pressure barrier (21) being configured to prevent water from flowing through the opening (7) and the aperture (12) into the interior space (4) during operation of the float deployment mechanism (41). 3. An apparatus according to claim 1, including an alignment pin (116) extending from the cofferdam (110); the line (50) being connected in use to a distal end of the alignment pin (116); the alignment pin (116) being receivable in use in the opening (7) and the aperture (12) to locate the cofferdam (110) on the wet side (5) of the wall (2).

4. An apparatus according to claim 1, wherein the line puller (20) includes a spool (22) for storing the line (50), the spool (22) being enclosed within the line puller pressure barrier (21). 5. An apparatus according to claim 4, wherein the line puller pressure barrier (21) includes a transparent window (23) for observing the operation of the line puller (20).

6. An apparatus according to claim 4, wherein the spool (22) is configured to be driven in rotation mechanically from outside the line puller pressure barrier (21).

7. An apparatus according to claim 6, wherein the line puller (20) includes a guide mechanism (28) for guiding the line (50) in an axial direction of the spool (22) during rotation of the spool, and the guide mechanism (28) is operable mechanically from outside the line puller pressure barrier (21).

8. An apparatus according to claim 1, including a valve (60) operable to selectively open and close a valve orifice (61); the valve (60) being sealingly and releasably connectable to the connection body

(60); the line puller pressure barrier (21) being sealingly and releasably connectable to the valve (60); the line puller (20) being operable in use to retract the line (50) through the opening (7) and the aperture (12) via the valve orifice (61).

9. An apparatus according to claim 8, including a plug (90) and a plug deployment tool (80); the plug (90) being sealingly engagable in the connection body (10); the plug deployment tool (80) being sealingly and releasably connectable to the valve (60) and operable to advance the plug (90) through the valve orifice (61) and to sealingly engage the plug (90) with the connection body (10); the plug deployment tool (80) including a pressure barrier (81) configured to prevent water from flowing through the opening (7) and the aperture (12) into the interior space (4) during operation of the plug deployment tool (80).

10. An apparatus according to claim 8, including a penetrator tool (70), the penetrator tool (70) being sealingly and releasably connectable to the valve

(60); the penetrator tool (70) including a cutter (71) and being operable, in the use position of the connection body (10), to advance and retract the cutter (71) through the valve orifice (61) and to operate the cutter (71) to cut the opening (7) through the wall

(2); the penetrator tool (70) including a pressure barrier (72) configured to prevent water from flowing through the opening (7) and the aperture (12) into the interior space (4) during operation of the penetrator tool (70).

11. An installation including: a structure (1) defining an interior space (4) and a submerged wall (2) that excludes a body of water (3) from the interior space (4), the interior space (4) being bounded by a dry side (6) of the wall; and an apparatus according to claim 1, wherein the connection body (10) is sealingly fixed to the dry side (6) of the wall in the use position to surround an opening (7) formed through the wall (2) in fluid communication with the aperture (12).

12. An installation according to claim 11, including at least two said connection bodies (10) sealingly fixed in spaced relation to the dry side (6) of the wall, each in the use position to surround a respective opening (7) formed through the wall (2) in fluid communication with the respective aperture (12), and at least two said line pullers (20) and line puller pressure barriers (21), each line puller pressure barrier (21) being sealingly connected to a respective one of the connection bodies (10), the line pullers (20) being operable to retract respective ones of at least two lines (50) connected to the cofferdam (110) at respective, spaced locations on the cofferdam (110).

13. A method of installing a cofferdam (110) on a wet side (5) of a submerged wall (2) that excludes a body of water (3) from an interior space (4) of a structure (1), the interior space (4) being bounded by a dry side (6) of the wall (2) opposite the wet side (5); the method including: sealingly engaging the cofferdam (110) against the wet side (5) of the wall (2) to define, and exclude water from, a temporary cavity (111) between the cofferdam (110) and the wet side (5) of the wall (2), and removing water from the temporary cavity (111); and further including, before sealingly engaging the cofferdam (110) against the wet side (5) of the wall (2): sealingly fixing a connection body (10) to the dry side (6) of the wall (2), and then forming an opening (7) through the wall (2), the opening (7) being surrounded by the connection body (10) and in fluid communication with an aperture (12) defined in the connection body (10), wherein a pressure barrier (72) is sealing connected to the connection body (10) to prevent water from flowing through the opening (7) and the aperture (12) into the interior space (4) while forming the opening (7); and further including: mounting a line puller (20) in the interior space (4); connecting the cofferdam (110) to a flexible line (50), the line (50) extending through the opening (7) and the aperture (12) to the line puller (20); and then operating the line puller (20) to retract the line (50) through the opening (7) and the aperture (12) to pull the cofferdam (110) against the wet side (5) of the wall (2); wherein a line puller pressure barrier (21) is sealingly connected to the connection body (10) to prevent water from flowing through the opening (7) and the aperture (12) into the interior space (4) during operation of the line puller (20). 14. A method according to claim 13, further including, before connecting the cofferdam (110) to the line (50): attaching a float (40) to a distal end of the line (50), and operating a float deployment mechanism (41) to advance the float (40) and the distal end of the line (50) from the interior space (4) through the opening (7) and the aperture (12) into the body of water (3) on the wet side (5) of the wall (2); the line puller pressure barrier (21) being configured to prevent water from flowing through the opening (7) and the aperture (12) into the interior space (4) during operation of the float deployment mechanism (41).

15. A method according to claim 13, further including: connecting the line (50) to a distal end of an alignment pin (116) extending from the cofferdam (110), and then retracting the line (50) to pull the alignment pin (116) into the opening (7) and the aperture (12) to locate the cofferdam (110) on the wet side (5) of the wall (2).

16. A method according to claim 13, further including: sealingly and releasably connecting a valve (60) to the connection body (10), the valve (60) being operable to open and close a valve orifice (61), and sealingly and releasably connecting the line puller pressure barrier (21) to the valve (60); and then opening the valve orifice (61) and operating the line puller (20) to retract the line (50) through the opening (7) and the aperture (12) via the valve orifice (61).

17. A method according to claim 16, further including: sealingly and releasably connecting a penetrator tool (70) to the valve (60), and operating the penetrator tool (70) to advance a cutter (71) through the valve orifice (61) and the aperture (12) and to operate the cutter (71) to cut the opening (7) through the wall (2).

18. A method according to claim 16, further including: releasing the cofferdam (110) from the wet side (5) of the wall (2) and removing the line (50) from the opening (7) and the aperture (12); and then closing the valve orifice (61) and removing the line puller pressure barrier (21) from the valve (60); and then sealingly and releasably connecting a plug deployment tool (80) to the valve; and then opening the valve orifice (61) and operating the plug deployment tool (80) to advance a plug (90) through the valve orifice (61) and to sealingly engage the plug (90) with the connection body (10).

19. A method according to claim 13, further including: sealingly fixing at least two said connection bodies (10) in spaced relation to the dry side (6) of the wall (2), mounting at least two said line pullers (20) in the interior space (4) and, for each of said line pullers (20), sealingly connecting a respective one of at least two said line puller pressure barriers (21) to a respective one of the connection bodies (10), and operating the line pullers (20) to retract respective ones of at least two lines (50) connected to the cofferdam (110) at respective, spaced locations on the cofferdam (110).

20. A method according to claim 19, further including removing the water from the temporary cavity (111) via a respective one of the connection bodies (10).