GB2582979A

GB2582979A - Apparatus for gripping a pile

Info

Publication number: GB2582979A
Application number: GB1905224.0A
Authority: GB
Inventors: Bernardini Jacopo; Cemiloglu Vildana; Murat Cemiloglu Berna
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-04-12
Filing date: 2019-04-12
Publication date: 2020-10-14
Anticipated expiration: 2039-04-12
Also published as: GB2582979B; GB201905224D0

Abstract

An apparatus 201 for gripping a pile has a casing 219 with a movable gripper ram 217 and a hydromorphic material 227, which, in use, expands upon exposure to liquid and pushes a portion of the gripper ram out of the casing into contact with the pile. The hydromorphic material can increase friction force between the gripper ram and the pile. The hydromorphic material may be wood. The casing may be provided with a valve 237 to allow water ingress into the casing to push the gripper ram using hydraulic force and also to swell the hydromorphic material.

Description

Apparatus for gripping a pile The present invention relates to an apparatus for gripping a pile, more particularly but not exclusively, to an apparatus for gripping a pile underwater. The present invention also relates to a substructure provided with one or more of such apparatus and a connector between a pile and a substructure, in which the substructure is secured to the pile by one or more such apparatus.

Historically in the offshore industry, offshore structures such as an offshore drilling rig or a wind turbine are installed, by securing them to the seabed. Typically, a fixed offshore substructure is secured to the seabed and extends upwardly to a point above sea level. A platform or tower, in accordance with the desired operation of the offshore structure, is then secured to the portion of the substructure which projects above the sea level.

The substructure can take the form of a transition piece, a jacket or a tripod. A transition piece is normally used together with a monopile, which is usually circular in I S cross section and manufactured from steel. A portion of the monopile resides within the substratum below the seabed and a portion of the monopile extends upwardly from the seabed. The transition piece, a portion of which having a bore running therethrough is also circular in cross section and is placed over the monopile portion extending upwardly from the seabed. The annular space between the monopile and the transition piece is filled with a cementitious grout slurry. This is commonly referred to as a "grouted connection".

Pile hammer machinery can be used at the surface to hammer the monopile into the substratum. Alternatively bore holes are drilled into the substratum in which a portion of the pile is then lowered into.

A jacket and a tripod are secured to the seabed in a similar way, however multiple piles are used. In particular, piles are inserted into the substratum at desired locations, either by hammering or by boring, as previously described. The jacket or tripod is then lowered toward the seabed, and legs or sleeves (with bores therethrough) provided on the jacket or tripod are aligned with the piles. The jacket or tripod is then lowered further so that respective legs or sleeves affixed to the jacket or tripod pass over the respective portions of the piles which are extending upwardly from the seabed. The jacket or tripod then comes to rest directly on the seabed, with the piles residing in the respective bores of the legs or sleeves. The annular space between the piles and the legs or sleeves on the jacket or tripod are filled with a cementitious grout slurry, commonly referred to as a "grouted connection".

Alternatively, the jacket or tripod can first be lowered onto the seabed and then 5 the piles can be hammered or inserted via boring into the substratum, using the legs or sleeves on the jacket or tripod as guides.

In all of these arrangements, the grouted connection is what reliably secures the substructure to the seabed.

It is known to temporarily hold the jacket or tripod leg or sleeve in position around 10 the pile with the use of hydraulically actuated centralisers, whilst the grouting connection is being formed. See for example, YouTube video titled: "SapuraAcergy Pipelay and Wellhead Construction, Devil Creek Development Project". Link: littps-Pwww.youtube.com/vvalch?v-XytliKACIle0 However, the grouting connection itself is still essential to sufficiently secure the I5 offshore structure to the piles and thereby the seabed.

For a grouting connection to be reliable, sufficient time must be available to allow for installation as well as adequate subsea placement and the curing of the grout. This is completely dependent on the surrounding weather conditions. If the weather is not suitable, then the offshore installation process takes longer, because the installation vessels used in such process are forced to wait around before work can continue or commence. This is highly undesirable as it increases the cost of installation.

Furthermore, if the surrounding weather conditions are not ideal and the grouting process is carried out, there is a risk that the resulting grouting connection is not sufficiently reliable. This could have adverse consequences, firstly it could increase overall installation costs due to necessary repairs. Secondly, it could increase the risk that the offshore structures are not properly secured. This could result in such a structure becoming disconnected from the seabed, consequently causing damage to equipment and injury to the crew.

These risks are multiplied when multiple piles are used to secure a single 30 offshore structure, e.g. in the case when a jacket or a tripod is used as the substructure. Additionally, the risk is yet further multiplied when the installation vessel is scheduled to install multiple offshore structures during a single voyage.

There is therefore a need for an alternative way to secure an offshore structure to a pile in the substratum, which carries reduced risks. The present invention attempts, in at least its preferred embodiment, to provide such an alternative.

The present invention provides an apparatus for gripping a pile, which apparatus comprises a casing having a gripper ram moveable with respect to the casing, the apparatus further comprising a hydromorphic material, which, in use, expands upon exposure to liquid and pushes a portion of the gripper ram out of the casing into contact with the pile.

Optionally the apparatus includes a first piston, wherein the gripper ram is 10 mounted on the first piston. It may be that the gripper ram simply sits adjacent the first piston, so that when the first piston is moved, it pushes the gripper ram.

Optionally a portion of the gripper ram passes through the first piston and is secured thereto via a nut and bolt arrangement. It may be that the gripper ram is secured to the first piston via welding or any other suitable means.

Optionally a first wedge locking mechanism is mounted on the piston to permit, in use, the piston to move in a first direction to push the portion of the gripper ram out of the casing, but inhibit the first piston from moving in the opposing direction.

Optionally a first locking spring is mounted on the piston and the first wedge locking mechanism. It may be that the first locking spring keeps the first wedge locking 20 mechanism in position on the first piston so as to inhibit the first piston from moving in the opposite direction.

Optionally the hydromorphic material is positioned such that, in use, it expands upon exposure to liquid and pushes the first piston which in turn pushes the portion of the gripper ram out of the casing.

Optionally the hydromorphic material is wood. It may be that the hydromorphic material is Swedish Oak, Red Oak, English Oak, Sapele, Greenheart, Teak, Ekki, Mahogany, Manbarklak, Iroko, Opepe or any combination thereof.

Optionally a second piston is provided in the casing and a second wedge locking mechanism and a second locking spring are mounted on the second piston and wherein 30 the second piston is provided on an opposing side of the hydromorphic material in relation to the first piston. It may be that the second piston provides a surface for the hydromorphic material to push off against, in order to ensure that only the first piston and the gripper ram are moved within the casing.

Optionally the casing is provided with a valve for the inlet of a liquid into the casing. It may be that the fluid is freshwater, saltwater, any other suitable liquid or any 5 combination thereof.

Optionally a sealing ring is provided around the gripper ram. It may be that the sealing ring seals the gripper ram about an outer side wall of a housing, to inhibit liquid moving from within the casing into the housing and vice versa.

Optionally the casing is provided with at least one recess to permit the movement of liquid along the length of the casing. Optionally at least one of the first piston and second piston is provided with a recess to permit the movement of liquid from one side of the at least one of the first piston and second piston to its opposing side. This may facilitate the movement of the first and second piston within the casing. This could inhibit hydraulic lock.

Optionally the apparatus is secured to a housing having a side wall and an end wall which define a cavity therein for accommodating a pile, and such that, in use, the gripper ram is movable out of the casing and into the cavity of the housing to contact the pile.

Optionally the apparatus is secured to the side wall of the housing. It may be that 20 the apparatus is secured to the side wall of the housing via welding.

Optionally a plurality of apparatus are secured to the side wall of the housing. Optionally the plurality of apparatus are secured to the side wall of the housing such that they are spaced apart from each other by approximately 90°.

Optionally a set of four apparatus are secured to the side wall of the housing such that they are spaced apart from each other by approximately 90° and wherein a second set of four apparatus are secured to the side wall of the housing such that they are spaced apart from each other by approximately 90° and spaced from the first set of four apparatus along the length of the housing. This arrangement may provide an accumulation of frictional forces between the gripping rams and the piles which is suitable to secure a substructure to piles extending from the seabed. It could be that the strength of the connection is comparable to strength of the prior art grouted connection.

Optionally the housing is secured to a substructure. It may be that the housing is secured to the substructure via welding.

Optionally a plurality of housings are secured to the substructure, such that a housing is secured to each respective lower corners of the substructure.

The present invention also provides a housing with at least one apparatus in accordance with the present invention provided thereon.

Optionally a guide is provided on the side wall of the housing to facilitate the entry of a pile within the cavity of the housing. This may make it easier to align respective housings with their respective piles.

t0 The present invention also provides a substructure with at least one housing in accordance with the present invention provided thereon.

The present invention also provides a method of securing a substructure to at least one pile extending from the seabed, which method comprises the steps of: accommodating the at least one pile in a cavity of a housing on the substructure; activating a valve on an apparatus to permit a liquid to enter into a casing of the apparatus; moving a portion of a gripper rod out from the casing into the cavity of the housing and into contact with the pile as a result of hydraulic force from the liquid; and expanding a hydromorphic material within the casing so that it urges a portion of the gripper rod against the pile and increases the frictional force between the gripper rod and the pile.

For a better understanding of the present invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a schematic side view in partial cross section of a prior art 5 arrangement for securing a substructure to piles; Figure 2 is a side view of twelve apparatus in accordance with the present invention, in use with a substructure and two piles; Figure 3 is an enlarged portion of six apparatus, in use with a substructure and a pile as shown in Figure 2; Figure 4 is a side view in cross section of four apparatus, in use with a pile as shown in Figure 3; and Figure 5 is a side view in cross section of a single apparatus as shown in Figure 4.

Referring to Figure 1 of the drawings, there is shown a prior art arrangement comprising a substructure in the form of a jacket 101 sitting on the seabed 103, with a portion of the jacket 101 extending above the surface of the sea level 107. The jacket 101 is provided with legs 109 which are open at both ends and each of which has a bore running therethrough.

Piles 111 have been driven into the seabed 103, so that a portion of each of the 20 respective piles 111 extends downwardly into the substratum below the seabed 103 and a portion of each of the respective piles 111 extends upwardly from the seabed 103. Upon installation, the jacket 101 is lowered down from an installation vessel (not shown) towards the seabed 103 and the legs 109 are aligned with the piles 111. The jacket 101 is then further lowered onto the seabed 103 to rest thereupon, and the legs 25 109 pass over the respectively aligned portions of the piles 111 extending upwardly from the seabed 103. So that the upwardly extending portions of the piles 111 reside in the bores of the respective legs 109 of the jacket 101.

The annulus between the piles 111 and their respective legs 109 of the jacket 101 in which they reside is then filled with a cementitious grout slurry. Hydraulically actuated centralisers (not shown) provided in the leg 109 can be used to temporarily hold onto the pile 111 therein to maintain an annulus of substantially uniform thickness, whilst the grouting process is taking place.

Once the grout slurry has cured, a strong connection is formed, securing the jacket 101 to the piles 111 and thereby the seabed 103. This connection is commonly known as a grouted connection 113.

A tower 105 is secured to the portion of the jacket 101 which extends above the 5 surface of the sea level 107, which tower is utilized for whatever the specific purpose the offshore structure is installed for, e.g. a wind turbine.

The disadvantage of securing the jacket 101 to the piles 111 and thereby the seabed 103 via the grouted connection is the dependency on the surrounding weather conditions. For a grouting connection to be reliable, sufficient time must be available to allow for installation, adequate subsea placement and the curing of the grout. This available time is completely dependent on the surrounding weather conditions. If the weather is not suitable, then the offshore installation process takes longer, because the installation vessels used in such process are forced to wait around before work can continue or commence. This is highly undesirable as it increases the cost of installation.

These risks are multiplied when multiple piles are used to secure a single offshore structure, e.g. in the case when a jacket or a tripod is used as the substructure. Additionally, the risk is yet further multiplied when the installation vessel is scheduled to install multiple offshore structures during a single voyage.

Referring to Figure 2, there is shown twelve of thirty-two apparatus in accordance with the present invention securing a substructure to two of the four piles. The apparatus, which are each generally identified by reference numeral 201 are mounted on a respective housing 203. The housing 203 is secured to a substructure, in particular a jacket 205, by welding at a lower corner thereof.

Additional housings provided with additional respective apparatus are also welded to the jacket 205 at other locations, e.g. at each of the remaining three lower corners the four corners of the jacket 205.

Piles 207 are driven into the substratum 209 below the seabed 211, so that a 5 portion of each of the respective piles 207 extends downwardly into the substratum 209 below the seabed 211 and a portion of each of the respective piles 207 extend upwardly from the seabed 211.

Upon installation, the jacket 205 is lowered down from the installation vessel (not shown) towards the seabed 211. The jacket 205 is aligned with the portions of the piles which extend upwardly from the seabed 211. The jacket 205 is secured to the piles 207 via the apparatus 201 provided in the housing 203 (and the additional housings provided with additional respective apparatus).

The jacket 205 is designed so that once its lower end is secured to the piles 207 and thereby the seabed 211, a portion of the jacket 205 extends above the surface of I5 the sea level. A tower (not shown) can then be secured to the portion of the jacket 205 which extends above the surface of the sea level, which tower is utilized for whatever the specific purpose the offshore structure is installed for, e.g. a wind turbine.

As better shown in Figure 3, the apparatus 201 are arranged around the housing 203, which is circular in horizontal cross section. A set of four apparatus 201 are spaced around an upper portion of the housing 203 at approximately 90' from each other. A further set of four apparatus 201 are spaced around a lower portion of the housing 203 at approximately 90' from each other.

As better shown in Figure 4, the housing 203 is provided with an inner side wall 213a and an outer side wall 213b, through which the apparatus 201 are secured (only four of the eight apparatus 201 are currently shown). A gap is provided between the inner side wall 213a and the outer side wall 213b. The housing 203 is further provided with an end wall 215 at an upper end of the side walls 213a,213b, to define a cavity therein and wherein the opening of the cavity is at the lower end of the side walls 213a,213b.

Upon installation, the jacket 205 with the respective housings 203 welded thereto is lowered towards the seabed 211 and the housings 203 are aligned with the respective piles 207 extending upward from the seabed 211. The jacket 205 is then further lowered, so that each housing 203 passes over each respective pile 207, and the cavities are moved to accommodate their respective piles 207.

The top of the pile 207 either abuts the end wall 215 or the jacket 201 abuts the seabed 211, resulting in a small spacing between the top of the pile 207 and the end wall 215 of the housing 203. A clearance distance of approximately 50mm to 100mm is present between the pile 207 and the inside of the inner side wall 213a. The housing is provided with a lower guide 216 to guide the housing 203 over the pile 207.

The apparatus 201 each comprise a gripper ram 217, which upon activation abuts the pile 207 contained within the cavity of the housing 203. It is the accumulation of each gripper ram 217 of each of the apparatus 201 gripping each pile 207 which provides the secure and reliable connection between the jacket 203 and the piles 207 and thereby the seabed 211.

As better shown in Figure 5, an apparatus 201 comprises a casing 219 having a rear piston 221 provided therein which is moveable within the casing 219. The rear piston 221 is mounted with a rear wedge locking mechanism 223 mounted on a rear locking spring 225, which in use, allows the rear piston 221 to move in the direction A but not in the direction B. The rear wedge locking mechanism 223 and the rear locking spring 225 are secured to the rear piston 221 via nuts and bolts.

Adjacent the rear piston 221, there is provided a block of hydromorphic material 227. This may be wood for example. Adjacent the block of hydromorphic material 227 is a front piston 229 which is mounted with a front wedge locking mechanism 231 mounted on a front locking spring 233. This arrangement, in use, allows the front piston 229 to move in the direction A but not in the direction B. Adjacent the front piston 229 is the gripper ram 217, which is moveable out of the casing 219 (in direction A) and into the cavity of the housing 203. The gripper ram 217 is sealed about the inner surface of the side wall of the housing 203 via a sealing ring 235. The gripper ram 214 comprises a main portion 239 which in use, contacts the pile 207, and a tail portion 241 which is secured to the main portion 239. The gripper ram 214 is secured to the front piston 229 and front locking spring 233 via the tail portion 241 which passes through a hole in the front piston 229 and front locking spring 233. A nut is then secured to a threaded portion at the end of the tail portion 241 of the gripper -10 -ram 217 in order to hold the gripper ram 217, the front piston 229 and the front locking spring 233 together.

When the housing 203 is positioned over a pile 207, such that the pile 207 resides within the cavity in the housing 203, the gripper ram 217 in each of the apparatus 5 201 in the housing 203 can be activated.

To do this, an electric valve 237 is opened to allow water to enter the casing 219 of each apparatus 201 via hoses (not shown) attached to the respective electric valves 237. The hydraulic water pressure in the casing 219 is sufficient to push the rear piston 221 in the direction A, which in turn pushes the block of hydromorphic material 227 in the direction of A, which in turn pushes the front piston 229 in the direction A. This in turn pushes the gripper ram 217 in the direction A and into abutment contact with the pile 207 in the cavity of the housing 203.

The front wedge locking mechanism 231 and the front locking spring 233 prevent the gripping ram 217 from moving in the direction B. During this time the block of hydromorphic material 227 becomes in contact with the water and starts to expand. After the gripper ram 217 has come into abutment contact with the pile 207, the electric valve 237 can be closed and the supply of water into the casing 219 stopped.

The rear wedge locking mechanism 223 and the rear locking spring 225 prevents the rear piston 221 from moving in the direction B as a result of the block of hydromorphic material 227 expanding. Thereby the expanding block of hydromorphic material 227 pushes against the front piston 229 and pushes this in the direction of A, which in turn pushes the gripper ram 217 in the direction of A. This increases the pressure of the gripper ram 217 on the pile 207, increasing the overall gripping force the housing 203 has on the pile 207.

The front wedge locking mechanism 231 and the front locking spring 233 again prevent the gripping ram 217 from moving in the direction B, so as to maintain the increased pressure of the gripping ram 217 on the pile 207.

The sealing ring 235 inhibits water from inside the casing 219 from entering into 30 the cavity within the housing 203 and vice versa.

It should be understood that water can move between the electric valve 237 and the volume within the casing 219 between the front piston 229 and the inner side wall 213a of the housing 203. This is to enable the gripping ram 217 to move into contact with the pile 207, upon actuation. Recesses are provided on the inside of the casing 219 and in the edges of the front piston 229 and rear piston 221 to facilitate the movement of water from one side of a piston to the other and to facilitate the movement of the front piston 229 and the rear piston 221 within the casing 219.

A vent 243 is provided through the casing 219. The vent 243 is provided with a non-return valve 245 to inhibit hydraulic lock from occurring during the movement of the first piston 229 and the hydromorphic material 227 in the direction A. The overall arrangement provides a reliable and secure connection between the jacket 205 and the piles 207 and thereby the seabed 111, without the use of a grouted connection as relied upon in the prior art. In this manner, the installation process can be carried out at a faster rate and at reduced cost. This is due to the fact that the surrounding weather conditions are not as disruptive for the installation because no grouted connection needs to be formed.

IS For completeness, a hydromorphic material is a material which changes shape in response to change in surrounding humidity or contact with liquid water. Depending on the particular hydromorphic material, it can either expand or contract when exposed to a certain level of humidity or contact with liquid water. Different examples of hydromorphic materials include wood and hydromorphic polymers. The rate of shape change of the material depends on the hydromorphic material itself as well as the level of humidity or liquid water the material is subject to.

The present invention concerns only the hydromorphic materials which expand upon exposure to liquid water. Wood is a particularly suitable hydromorphic material for use in accordance with the present invention and it has a high tangential expansion rate and is strong. In particular, hard woods are preferred, for example: Swedish Oak, Red Oak, English Oak, Sapele, Greenheart, Teak, Ekki, Mahogany, Manbarklak, Iroko or Opepe. Hard woods particularly from tropical areas are preferred.

In the preferred embodiment, the casing 219 is 575mm in length, with an inner diameter of 400mm and an outer diameter of 500mm. The front piston 229 and rear piston 221 are both 400mm in diameter and 116mm in thickness. Both the front piston 229 and the rear piston 221 are provided with shoulders to accommodate the wedge locking mechanisms 231 and 223 respectively. These shoulders are at an angle of 15° to the horizontal. Therefore the front wedge locking mechanism 231 and the rear wedge locking mechanism 223 extend through 1512 from the horizontal. The main portion 239 of the gripper ram 217 is 125mm in dimeter and 232mm in length. The tail portion 241 of the gripper ram is 26mm in diameter and 77mm in length. Therefore the total length of the gripper ram 217 is 309mm.

The casing 219, the gripper ram 217, the front piston 229, the front wedge locking mechanism 231, the front locking spring 233, the rear piston 221, rear wedge locking mechanism 223, rear locking spring 225 are manufactured from stainless steel. Various modifications to the embodiments described are envisaged. In 10 particular, it is conceivable that the front piston and the rear piston could be disposed with and the casing simply contains one or more blocks of hydromorphic material. However, the arrangement described with respect to Figures 2 to 5 is preferred since it enables differences in thicknesses of the annular space between the piles and the housing to be accommodated.

Furthermore, the electric valve 237 could be replaced with a mechanically actuated valvue. It could be that at least one centralized valve may be used, to active multiple grippers in parallel. It may be that it is not necessary for the valve (electric valve 237 or otherwise) to be closed. In that, the apparatus 201 can still function with the valve left open, as long as the hydraulic pressure from the water has moved the gripper ram 20 217 forward and water has come into contact with the hydromorphic material 227. It may be that the water is fresh water or salt water. It could be that any suitable combination of these is used.

It may be that the end of the gripper ram 217, which abuts the pile 207, is provided with grooves and/or sharp protrusions to enhance its grip on the pile 207 when in use.

It could be that the gap between the inner side wall 213a and the outer side wall 213b of the housing 203 contains a stiffening structure, to strengthen the casing 203. It may be that the housing is provided with a single solid side wall.

It may be that the tail portion 241 is fixed to the main portion 239 of the gripper 30 ram 217 via welding, or the tail portion is integral with the main portion 239.

It is foreseeable that the dimensions could be varied in order to be best suited to a specific project.

101 Jacket 103 Seabed Tower 107 Sea level 109 Legs 111 Piles 113 Grouted connection 201 Apparatus 203 Housing 205 Jacket 207 Piles 209 Substratum 211 Seabed 213 Side wall 215 End wall 216 Guide 217 Gripper ram 219 Casing 221 Rear piston 223 Rear wedge locking mechanism 225 Rear locking spring 227 Hydromorphic material 229 Front piston 231 Front wedge locking mechanism 233 Front locking spring 235 Sealing ring 237 Electric valve 239 Main portion 241 Tail portion 243 Vent 245 Non-return valve -13 -

Claims

-14 -Claims: 1. An apparatus for gripping a pile which apparatus comprises a casing (219) having a gripper ram (217) moveable with respect to said casing (219), the apparatus further comprising a hydromorphic material (227), which, in use, expands upon exposure to liquid and pushes a portion of the gripper ram (217) out of the casing (219) into contact with said pile (207).
2. An apparatus as claimed in Claim 1, including a first piston (229), wherein said gripper ram (217) is mounted on said first piston (229).
3. An apparatus as claimed in Claim 2, wherein a portion of the gripper ram (217) passes through the first piston (229) and is secured thereto via a nut and bolt arrangement.
4. An apparatus as claimed in Claim 2 or 3, wherein a first wedge locking mechanism (231) is mounted on the piston (229) to permit, in use, the piston (229) to move in a first direction to push the portion of the gripper ram (217) out of the casing (219), but inhibit the first piston (229) from moving in the opposing direction.
5. An apparatus as claimed in Claim 4, wherein a first locking spring (233) is mounted on the piston (229) and the first wedge locking mechanism (231).
6. An apparatus as claimed in any preceding claim, wherein the hydromorphic material (227) is positioned such that, in use, it expands upon exposure to liquid and pushes the first piston (229) which in turn pushes the portion of the gripper ram (217) out of the casing (219).
7. An apparatus as claimed in any preceding claim, wherein the hydromorphic material (227) is wood.
8. An apparatus as claimed in Claim 7, wherein the hydromorphic material (227) is Swedish Oak, Red Oak, English Oak, Sapele, Greenheart, Teak, Ekki, Mahogany, Manbarklak, Iroko, Opepe or any combination thereof.
-15 - 9. An apparatus a claimed in any of Claims 2 to 8, wherein a second piston (221) is provided in the casing (219) and a second wedge locking mechanism (223) and a second locking spring (225) are mounted on the second piston (221) and wherein the second piston (221) is provided on an opposing side of the hydromorphic material (227) in relation to the first piston (229).
10. An apparatus as claimed in any preceding claim, wherein the casing (219) is provided with a valve (237) for the inlet of a liquid into the casing (219).
11. An apparatus as claimed in any preceding claim, wherein a sealing ring (235) is provided around the gripper ram (214).
12. An apparatus as claimed in any preceding claim, wherein the casing (219) is provided with at least one recess to permit the movement of liquid along the length of the casing (219).
13. An apparatus as claimed in any of Claims 2 to 11, wherein at least one of the first piston (229) and second piston (221) is provided with a recess to permit the movement of liquid from one side of the at least one of the first piston (229) and second piston (221) to its opposing side.
14. An apparatus as claimed in any preceding claim, wherein the apparatus (201) is secured to a housing (203) having a side wall (213a,213b) and an end wall (215) which define a cavity therein for accommodating a pile (207), and such that, in use, the gripper ram (217) is movable out of the casing (219) and into the cavity of the housing (203) to contact the pile (207).
15. An apparatus as claimed in Claim 14, wherein the apparatus (201) is secured to the side wall (213a,213b) of the housing (203).
16. An apparatus as claimed in Claim 15, wherein a plurality of apparatus (201) are secured to the side wall (213a,213b) of the housing (203).
17. An apparatus as claimed in Claim 16, wherein the plurality of apparatus (201) are secured to the side wall (213a,213b) of the housing (203) such that they are spaced apart from each other by approximately 90'.
18. An apparatus as claimed in Claim 17, wherein a set of four apparatus (201) are secured to the side wall (213a,213b) of the housing (203) such that they are spaced apart from each other by approximately 90' and wherein a second set of four apparatus (201) are secured to the side wall (213a,213b) of the housing (203) such that they are spaced apart from each other by approximately 90' and spaced from the first set of four apparatus (201) along the length of the housing (203).
19. An apparatus as claimed in any of Claims 14 to 18, wherein the housing (203) is secured to a substructure. I5
20. An apparatus as claimed in Claim 19, wherein the housing (203) is secured to the substructure via welding.
21. An apparatus as claimed in Claims 19 or 20, wherein a plurality of housings (203) are secured to the substructure, such that a housing (203) is secured to each respective lower corners of the substructure.
22. A housing with at least one apparatus (201) as claimed in any of Claims 1 to 21, provided thereon.
23. A housing as claimed in Claim 22, wherein a guide (216) is provided on the side wall (213a,213b) of the housing (203) to facilitate the entry of a pile (207) within the cavity of the housing (203).
24. A substructure with at least one housing as claimed in Claims 22 or 23, provided thereon.
25. A method of securing a substructure to at least one pile extending from the seabed, which method comprises the steps of: -17 -accommodating the at least one pile (207) in a cavity of a housing (203) on the substructure; activating a valve (237) on an apparatus (201) to permit a liquid to enter into a casing (219) of the apparatus (201); moving a portion of a gripper rod (217) out from the casing (219) into the cavity of the housing (203) and into contact with the pile (207) as a result of hydraulic force from the liquid; and expanding a hydromorphic material (227) within the casing (219) so that it urges a portion of the gripper rod (217) against the pile (207) and increases the frictional force between the gripper rod (217) and the pile (207). I5