CN1867483A - A method of constructing a semi-submersible vessel using dry dock mating - Google Patents

Abstract

A method of constructing a semi-submersible drilling rig in a shipyard and fully assembling it in a shipyard. The upper hull (1) is constructed on land adjacent to the dry dock in which the lower hull (2) is constructed and the joining of the upper and lower hulls is finally done in the dry dock. The upper shell slides to a position above the lower shell, and the lower shell is floated up by injecting water into the dry dock, and the position of the lower shell is adjusted through the ballast tank in the lower shell. Once the upper and lower hulls are in contact alignment, they are permanently welded together, completing the rig assembly in dry dock.

Description

A method of constructing a semi-submersible vehicle using a dry-dock mating connection

technical field

The present invention relates generally to a method of building an off-shore structure, and in particular to a method of building a semi-submersible drilling rig, vessel or structure (referred to as a "drilling rig") in a dock.

Background technique

There is an increasing demand in the market for semi-submersible drilling equipment capable of oil and gas exploration at depths of more than 150 meters.

There are currently two conventional methods of constructing semi-submersible drilling rigs. The first, the so-called "sequential block build-up" method, provides a method of sequentially building semi-submersible rigs "from bottom to top". According to this method, the lower shell of the platform is floating, and the pillars and connecting supports are first erected piece by piece using a shore crane or a floating crane on water. The upper housing which then stands on the lower housing is assembled in the same way. A major disadvantage of this approach is the extensive use of shore and floating cranes. Frequently, the progress of the construction depends on the capacity of the floating cranes on the water. Furthermore, the welding work of a large number of connecting blocks will result in a long construction period. On the other hand, the installation and trial operation of ancillary equipment (outfitting) and main equipment can only be carried out on the drilling equipment after the erection of all the drilling equipment is completed. This will in turn lead to a longer overall construction period and a delay in the commissioning of the equipment, especially affecting the drilling rig in the central part of the upper casing.

A second existing method of building a semi-submersible rig is to build the upper and lower hulls of the platform simultaneously and then join the two halves together. According to this method, the upper hull is loaded on a barge and both the upper and lower hulls are towed to a position on the sea surface where the water depth is sufficient to accommodate the lower hull. The lower hull is then sunk to the required depth with ballast and balancing devices, only the tops of the struts are exposed above the sea surface for temporary berthing, the power supply system and complex input systems also require this type of operation. A barge transports the upper shell and positions it on top of the lower shell. Before mating, the barge must be secured in position against the lower hull. The floating barge then gradually sinks in the water under the action of the ballast until the bottom of the upper hull touches the lower hull struts. Welding at the junction between the upper and lower shells is the final operation. The main disadvantage of this method is that the connection operation is usually very risky, and the sea environment is harsh and uncontrollable. Moreover, this operation may face a large number of uncertainties. The security and quality of this connection operation will be the main concern.

Other methods of constructing offshore drilling rigs are also disclosed in numerous published or disclosed patent documents. For example, in US Pat. No. 6,347,909 issued on February 19, 2002, a method of constructing a drilling rig is disclosed, which transports a deck to the sea surface and installs the deck on the substructure of the sea surface. The entire deck is fabricated on a set of deep steel frames used to support the jacking units. Fastened together decks and multi-level steel frames slide onto two pontoons. The entire assembly is towed to the installation site where the steel frame is jacked up while the pontoon is pushed down until the assembly is supported by the pontoon. The deck was then lowered onto the substructure and the pontoons were removed.

Another patented method disclosed in US Pat. No. 6,340,272 issued on January 22, 2002, is to construct an offshore platform by joining a self-floating deck structure with a self-floating substructure. The self-floating deck structure may be a floating pier or barge on which the required equipment is already installed. The joint is achieved by partially submerging the substructure in water, over which a quay or barge is positioned, and subsequently deballasting the foundation to create a vertically oriented bearing force between the substructure and the quay or barge.

Another patented method, US Pat. No. 5,924,822 issued on July 10, 1999, discloses a device and method for installing a deck on a marine substructure. Two separate pontoons each contain two struts spaced apart from each other and extending upwardly from the pontoons. Each pontoon is provided with ballast tanks and is filled with ballast during transport. The pontoon allows the deck to be placed directly above the sea surface substructure. The pontoon is ballasted while the floating substructure is deballasted to move the deck to the floating substructure.

US Patent No. 5,237,949 issued on August 24, 1993 discloses a method of constructing and assembling an offshore platform, wherein the ordinary draft of the offshore platform exceeds the depth of the waterway between the construction site and the platform service location. The hull and deck of the platform are fabricated separately in a shallow dry dock. The dry dock is partially filled with water, the hull floats up to engage the deck and the platform is then raised.

Japanese Patent No. 56-154381 published on November 28, 1981 discloses a semi-submersible drilling rig consisting of a pair of pontoons, an upper deck and pillars. The end portions of the connecting members of the struts and the deck end portions are fastened together. Subsequently, the deck, pontoon and struts are ballasted to align the central portion of the connecting member with the central portion of the deck while adjusting the inclination of the struts.

Although these patented methods allow the construction of semi-submersible rigs under certain conditions, there is still a need for a simpler, safer and more cost-effective method that can be built close to the dock, preferably in the dock Implemented assembly scheme.

Contents of the invention

It is therefore an object of the present invention to provide a method of building a semi-submersible drilling rig which is safe, reliable and relatively low cost compared to other methods.

Another object of the present invention is to provide a method of constructing a semi-submersible drilling rig both on shore and in dry dock of conventional docks.

These and other objects of the invention are achieved by the provision of a method which allows simultaneous construction of the upper and lower hulls in the dock and thus shortens the overall construction schedule. On shore, the upper hull is erected entirely on the sliding trusses and support towers, while the lower hull is built in dry dock next to the sliding trusses. A support truss is installed in the dry dock to support a plurality of sliding beams extending all the way from the upper hull construction site on shore to the engagement location above the lower hull in the dry dock.

Once the upper and lower shells are constructed, the upper shell is slid into joint position on sliding beams using a hydraulic jacking system. This is followed by a mating operation in which the lower hull in dry dock is floated up until it contacts and supports the upper hull. Welding at the junction of the upper and lower shells is performed last. By such a method, the entire joining operation can be carried out under control, which guarantees the safety and quality of the operation.

Description of drawings

In order to further understand the nature and purpose of the present invention, the following description will be combined with the accompanying drawings, wherein corresponding parts have provided corresponding symbols in the accompanying drawings, wherein:

1 and 2 are an external outline view and a top view of the carrying and engaging handling devices, respectively.

Figure 3 is a cross-sectional view of the upper shell supported by sliding trusses and building towers.

Figure 4 illustrates the steps involved in installing a support truss in a dry dock.

Figure 5 illustrates the position of the wedge member in the method of the present invention.

Figure 6 is a cross-sectional view illustrating the upper shell in the engaged position above the lower shell in dry dock.

Figure 7 illustrates the steps of the sliding truss procedure when the upper shell is fully supported by the lower shell and after the joining operation.

Figure 8 is a schematic diagram showing the separation of the sliding beam before the drilling rig is surfaced.

Fig. 9 is a schematic diagram illustrating the completion of the joining operation.

Detailed ways

Now described in more detail with reference to the accompanying drawings, Figures 1 and 2 show a general arrangement of a dock, including a dry dock, in which a semi-submersible drilling rig according to the present invention has been built and engaged. As shown in FIGS. 1 and 2 , the semi-submersible drilling equipment includes an upper shell 1 and a lower shell 2 . During construction, the upper hull 1 is supported by sliding trusses 3 located on the shore adjacent to the dry dock 4 . The truss 3 is also designed to be able to slide the entire upper shell on the sliding beam 6 using the sliding shoes 8 during unloading operations. The auxiliary support structure 5 or support truss 5 is erected in the dry dock 4 .

Sliding beams or connecting members 6 extend between the support truss 5 and the bottom of the sliding truss 3 . The connecting members 6 are removed from the support trusses after the joining operation is complete, as will be described in more detail below.

A cylindrical hydraulic jacking system 7 is mounted on the first sliding shoe 8 and an anchor block 9 is attached to the distal end of the sliding beam 6 . A strand wire (strand wire) 14 is connected to the anchor block 9 and the hydraulic jacking system 7 . Behind the support trusses 5 on the dry dock are arranged two barges 10 . The compartments of the barge 10 are filled with ballast. The barge 10 is connected to the distal end of the beam 6 by a tie bar 11 (tie bar). The barge 10 acts as a counterweight against the upward movement of the sliding beam 6 .

Before the upper shell 1 is built, a temporary support tower 16 is erected around the sliding truss 3 to support the upper shell 1 (as shown in FIG. 3 ). A working platform 19 is provided below the upper casing 1 . Vertical stairs 17 and horizontal walkways 18 provide access from the ground through the working platform 19 to the upper housing 1 . These components provide a safe and friendly working environment.

Figure 4 illustrates the installation of the mid-support truss 5 in a dry dock. It can be seen from the figure that the supporting truss 5 is composed of an upper part 5A and a lower part 5B. The lower part 5B has a connecting member 5C having an outer convex surface, and the upper part 5A has a connecting member 5D having an inner concave surface of a radius matching the radius of the convex part 5C. The lower section 5B is installed on the dry dock floor, after which the upper section 5A is installed with the barge 10 . The upper part 5A of the truss 5 is simply lowered to rest on the lower part 5B, bringing the convex 5C and concave 5D into mating engagement. Without welding, the fast installation and disassembly of the support truss 5 is realized, and the occupation time of the dry dock is shortened.

Figure 5 illustrates the features of the present invention related to friction enhancing means by positioning them between adjacent components during construction. Multiple wedge members, such as wooden wedges 13, are used to reduce the need for welding. In the partially enlarged view 1 of FIG. 5 , it can be seen that two wedge members 13 are mounted between the bottom of the upper shell 1 and the top of the sliding truss 3 . Similarly, as shown in view A of FIG. 5 and partially enlarged FIG. 2 , the support truss 5 and the sliding beam 6 are installed on the wedge-shaped members 13 between the dock floor and the support truss, respectively. The high compressive strength of the wood transfers vertical loads, and friction between adjacent member surfaces constrains the lateral transfer.

Once the upper shell 1 and lower shell 2 are built, the upper shell 1 is jacked up and slid along the sliding beam 6 into position above the lower shell 2 and substantially aligned with the lower shell 2 pillars. Figure 6 illustrates the position of the upper housing 1 and the position of the lower housing 2 after the former has reached the engaged position. A gap of approximately 500mm between the bottom of the upper housing and the top of the lower housing struts is sufficient.

The next step in the process is to float the lower shell. At this stage, the dry dock is filled with water. By discharging the ballast water in each water tank or transferring the ballast water in several tanks, the lower shell 2 is placed in the required floating state, and at the same time, the alignment of the upper shell and the lower shell is adjusted by means of floating . The tops of the pillars of the lower case 2 are finally in contact with the bottom of the lower case 1 . Welding of temporary guide blocks at the junction of the upper and lower shells is performed at this stage.

The lower shell 2 floats continuously until it supports the weight of the upper shell 1, and the gap between the upper shell 1 and the lower shell 2 is closed. The upper housing 1 is then completely removed from the sliding beam 3 . Sufficient welding is performed at the junction of the upper shell and the lower shell so that the lower shell 2 is permanently attached to the upper shell 1 .

After this joining step, the semi-submersible drilling rig has been removed from the auxiliary support structure 5 . The sliding truss 3 is brought back to shore from the engagement position using a hydraulic jacking system 7 mounted on the sliding truss 3 . The sliding beam 6 above the dry dock 4 is severed, pulled out and discharged onto the barge 10 using hydraulic jacking systems 7 , 9 mounted on the sliding beam 6 . The connecting beam 6 is then removed from the dry dock 4 using one or more transporters or shallow bay trailers 12 .

FIG. 8 shows the joint position of the entire drilling rig with casings 1 and 2 in dry dock 4 emerging from support trusses 5 .

FIG. 9 is a top view illustrating the removal of the drilling rig from the support truss 5 in the dry dock 4 .

Compared with the existing conventional drilling equipment construction method, the platform construction method provided by the present invention has the following advantages. By building the upper shell and the lower shell simultaneously, the total construction period is shortened. Risky and uncertain joining processes in harsh sea environments are avoided, thus ensuring high safety and quality. Thus, good alignment of the upper and lower housings and early commissioning of the device are possible.

The present method provides a suitable structure to support the upper shell taking into account changes in the load pattern throughout the installation of the upper shell. A safe working platform is set up under the upper shell, which enhances the safety of the present invention and makes the working environment very friendly. The tower provides vertical and horizontal safe access from the ground to the working platform below the upper shell. In addition, the upper housing can be slid into the engaged position without hindrance.

Supporting truss members are easy to install, easy to line up, and easy to remove. There is no need for any additional piling work on the dry dock floor. Potential problems caused by minor ground subsidence during sliding are completely eliminated, and interference between the cross braces of the lower shell and the supporting trusses is minimized or even eliminated.

An additional advantage of the method of the invention is the elimination of expensive ground anchor points to withstand the high tension forces involved in sliding engineering; using this method the sliding beams and support trusses are recovered and the sliding surfaces are protected. Wooden wedges allow better leveling of the mechanism and limit the lateral movement of the mechanism through friction between the surfaces.

While the invention has been described above with reference to particular embodiments, this description is not to be construed as limiting. Various variations of the disclosed embodiments, as with other embodiments of the invention, will become apparent to those skilled in the art upon reference to the description. Those skilled in the art can obviously make various changes on the basis of the present invention. But these changes should obviously be included in the claims of the present invention.

claims

(Amended in accordance with Article 19 of the Treaty)

1. A method for building semi-submersible drilling equipment, comprising the following steps

providing an upper hull and a sliding truss arrangement supporting the hull on land;

providing a lower hull adjacent to the sliding truss arrangement in dry dock;

providing a device mounted on the sliding truss device for moving the upper shell to a position above the lower shell;

Move the upper shell to a position above the lower shell;

Adjust the ballast in the lower shell so that the lower shell is aligned with the upper shell;

joining the upper shell to the lower shell, thereby assembling the semi-submersible drilling rig; and removing the semi-submersible drilling rig from the upper shell support means.

2. The method of claim 1, further comprising the step of providing an auxiliary truss support structure to temporarily support the upper shell while the upper shell is positioned above the lower shell, and wherein said removal from the sliding truss means The step of semi-submersible drilling rig further includes the step of removing the semi-submersible drilling rig from the auxiliary truss support structure.

3. The method of claim 1, wherein said step of providing a sliding truss arrangement further comprises the step of erecting a sliding truss and a plurality of tower superstructures prior to constructing an upper shell on said sliding truss and tower superstructure Structure to hold the upper hull in an elevated position on land for providing horizontal and vertical access to the upper hull.

4. The method of claim 3, further comprising the step of providing means for inhibiting horizontal movement of the upper shell relative to the sliding truss in the absence of welds between the upper shell and the sliding truss.

5. The method of claim 4, wherein said restraining means comprises a plurality of wedge-shaped members formed at least on a surface of a friction-increasing material, said wedge-shaped members mounted on a bottom surface of the upper housing between contact surfaces with the sliding truss.

6. The method of claim 2, wherein the step of providing the auxiliary truss support structure comprises the step of providing a support truss in dry dock and providing a connecting beam extending between the auxiliary truss support structure and the sliding truss arrangement.

7. A method as claimed in claim 6, further comprising the step of providing means for inhibiting horizontal movement of the auxiliary truss support structure relative to the dry dock in the absence of welds or anchors between the upper hull and the sliding trusses.

8. The method of claim 7, wherein said restraint means comprises a plurality of wedge-shaped members formed at least on the surface of a friction-increasing material, said wedge-shaped members mounted on the bottom surface of the auxiliary support structure and the dry dock between the bottom plates.

9. The method of claim 6, further comprising providing means for inhibiting horizontal movement of the connecting beam and the auxiliary truss supporting structure without welding between the auxiliary truss supporting structure and the connecting beam.

10. The method of claim 9, wherein said restraining means comprises a plurality of wedge-shaped members, at least one surface of which is formed of a friction-increasing material, said wedge-shaped members are mounted on the bottom surface of the connecting beam and the auxiliary truss support between the contacting surfaces of the structure.

11. The method of claim 6, wherein said means for moving the upper shell comprises a jacking system mounted on sliding truss means and connecting beams.

12. The method of claim 6, wherein said connecting beam has a proximal end, and said proximal end is secured to a sliding truss arrangement.

13. The method of claim 12, further comprising the step of releasably securing the distal ends of the connecting beams to a balancing device located at the rear of the auxiliary truss support structure.

14. The method of claim 1, further comprising the step of installing an auxiliary truss support structure on the dry dock floor.

15. The method of claim 14, wherein said auxiliary truss support structure comprises a lower portion having male connecting members and an upper portion having corresponding female connecting members, and said installing the auxiliary truss supporting structure on the dry dock floor The step comprises the step of matingly engaging the upper and lower portions of the auxiliary truss support structure.

16. The method of claim 2, wherein said step of removing the semi-submersible drilling rig from the auxiliary truss support structure includes the step of recovering the sliding truss assembly and connecting beams.

17. The method of claim 16, further comprising the step of pulling the sliding truss using a jacking system mounted on the sliding truss.

18. The method of claim 16, further comprising the step of pulling the connecting beam and unloading the connecting beam onto a plurality of transport devices using a jacking system mounted on the connecting beam.

19. A method for constructing a semi-submersible drilling rig in a shipyard, comprising the following steps:

Setting sliding trusses and multiple support towers on land;

Construction of the upper hull of the semi-submersible drilling rig on sliding trusses and support towers;

provision of support trusses adjacent to the sliding trusses in the dry dock;

Simultaneously with the construction of the upper hull, the lower hull of the semi-submersible drilling rig is constructed in dry dock;

Fasten the jacking system under the sliding truss;

providing a plurality of sliding beams fastened between the support truss and the lower part of the sliding truss;

Lift the upper shell and move the built upper shell along the sliding beam to a position above the built lower shell;

floating the lower hull in dry dock;

Adjust the ballast of the lower hull to align the lower hull with the upper hull;

Joining the upper hull to the lower hull to assemble the semi-submersible drilling rig in dry dock;

Removal of the semi-submersible rig from the slide truss and support truss.

20. The method of claim 19, wherein the sliding beam has a distal end removably connected to a counterweight for resisting rising of the sliding beam during transfer of the upper housing.

21. The method of claim 20, further comprising the step of installing support trusses on the dry dock floor.

22. The method of claim 21, wherein said support trusses comprise a lower portion having male connecting members and an upper portion having corresponding female connecting members, wherein said step of installing the supporting trusses on the dry dock floor comprises Pair the steps that join the upper and lower sections of the support truss.

23. The method of claim 20, further comprising the step of installing a friction-enhancing wedge member between at least the upper shell and the sliding truss, said wedge member being non-welded between the upper shell and the sliding beam case, restrain the lateral movement of the upper housing.

24. The method of claim 19, wherein the step of removing the semi-submersible drilling rig from the sliding truss and the support truss includes the step of recovering the sliding truss and the sliding beam.

25. The method of claim 24, further comprising the step of pulling the sliding truss using a jacking system mounted on the sliding truss.

26. The method of claim 24, further comprising the step of pulling the sliding beam and unloading the sliding beam onto a plurality of barges using a jacking system mounted on the sliding beam.

Claims (26)

1. a method of building semisubmersible drill rig comprises following step

Upper body is set and supports the device of this housing on land;

Lower case near the upper body bracing or strutting arrangement is set in dry dock;

A kind of device is provided, and this device is installed on the described upper body bracing or strutting arrangement, is used for upper body is moved to the position of lower case top;

Transfer the position of upper body to the lower case top;

Adjust the ballace in the lower case, lower case is aimed at upper body;

Join upper body to lower case, thus the assembling semisubmersible drill rig; And

Remove semisubmersible drill rig from the upper body bracing or strutting arrangement.

2. the method for claim 1, further comprise following steps: when upper body is positioned the lower case top, auxiliary support structure is set with temporary transient support upper body, and the wherein said step that removes semisubmersible drill rig from the upper body bracing or strutting arrangement further comprises step: driling rig removes semisubmersible drill rig from auxiliary support structure.

3. the method for claim 1, the wherein said step that the upper body bracing or strutting arrangement is set further comprises the steps: to set up slip truss and a plurality of tower superstructure before the upper body upper body is remained on the position that raise the land at structure on described slip truss and the tower superstructure, is used to provide the level and the vertical channel that lead to upper body.

4. method as claimed in claim 3 further is included under the situation that does not have welding between upper body and the slip truss, is provided with to suppress the step of upper body with respect to the device of the parallel motion of slip truss.

5. method as claimed in claim 4, wherein said restraining device comprises a plurality of tapered members, this tapered member is formed by the material that increases friction force on the surface at least, and described tapered member is installed between the mating surfaces of the lower surface of upper body and slip truss.

6. method as claimed in claim 2, the step that described auxiliary support structure wherein is set be included in dry dock sub-truss is set and be arranged on auxiliary support structure and the upper body bracing or strutting arrangement between the step of the tie-beam that extends.

7. method as claimed in claim 6 further is included under the situation that does not have welding between upper body and the slip truss or be anchored, and is provided with to suppress the step of auxiliary support structure with respect to the device of the parallel motion of dry dock.

8. method as claimed in claim 7, wherein said restraining device comprises a plurality of tapered members, and this tapered member is formed by the material that increases friction force on the surface at least, and described tapered member is installed between auxiliary support structure basal surface and the dry dock base plate.

9. method as claimed in claim 6 further is included under the situation of not welding between auxiliary support structure and the tie-beam, is provided for suppressing the device of the parallel motion of tie-beam and auxiliary support structure.

10. method as claimed in claim 9, wherein said restraining device comprises a plurality of tapered members, this tapered member surface is at least formed by the material that increases friction force, and described tapered member is installed between the mating surfaces of tie-beam basal surface and auxiliary support structure.

11. method as claimed in claim 6, the device of wherein said handover upper body comprise the jacking system that is installed on upper body and the tie-beam.

12. method as claimed in claim 6, wherein said tie-beam has near-end, and described near-end is fastened to the upper body bracing or strutting arrangement.

13. method as claimed in claim 12 further comprises the step that the far-end of tie-beam removably is fastened to the balancing device that is positioned at the auxiliary support structure rear portion.

14. the method for claim 1 further is included in the step that auxiliary support structure is installed on the dry dock base plate.

15. method as claimed in claim 14, described auxiliary support structure comprises the bottom with evagination transom and has the top of cooresponding indent transom, and the described step that auxiliary support structure is installed on the dry dock base plate comprises the step of the upper and lower pairing joint that makes auxiliary support structure.

16. method as claimed in claim 2, the wherein said step that removes semisubmersible drill rig from auxiliary support structure comprises the step that reclaims upper body bracing or strutting arrangement and tie-beam.

17. method as claimed in claim 16 further comprises the step of using the jacking system that is installed on the upper body bracing or strutting arrangement to pull on portion's housings support device.

18. method as claimed in claim 16 further comprises and uses the jacking system pulling tie-beam be installed on the tie-beam and described tie-beam is discharged to step on a plurality of conveying arrangements.

19. in dock, build the method for semisubmersible drill rig, comprise following steps:

Slip truss and a plurality of support tower are set on land;

On slip truss and support tower, build the upper body of semisubmersible drill rig;

The sub-truss that is adjacent to the slip truss is set in dry dock;

When building upper body, in dry dock, build the lower case of semisubmersible drill rig;

Fastening jacking system under the slip truss;

A plurality of sliding beams that are fastened between sub-truss and the slip truss bottom are set;

The jacking upper body also will be built good upper body along sliding beam and be transplanted on the position of building good lower case top;

Allow lower case in dry dock, float;

Adjust lower case ballace so that lower case aim at upper body;

Upper body is joined on the lower case, thereby in dry dock, assemble semisubmersible drill rig;

Remove semisubmersible drill rig from slip truss and sub-truss.

20. method as claimed in claim 19, wherein said sliding beam has far-end, and described far-end is detachably connected to the process that is used for transferring in upper body and resists the balancing device that sliding beam rises.

21. method as claimed in claim 20 further is included in the step that sub-truss is installed on the dry dock base plate.

22. method as claimed in claim 21, wherein said sub-truss comprises the bottom with evagination transom and has the top of corresponding indent transom, and the wherein said step that sub-truss is installed on the dry dock base plate comprises the step of pairing in conjunction with the sub-truss upper and lower.

23. method as claimed in claim 20, further comprise the step that the tapered member that improves friction force is installed at least between upper body and slip truss, described tapered member suppresses the side travel of upper body under the situation of not welding between upper body and the sliding beam.

24. method as claimed in claim 19, the wherein said step that removes semisubmersible drill rig from slip truss and sub-truss comprises the step that reclaims slip truss and sliding beam.

25. method as claimed in claim 24 further comprises use and is installed in the step that the slip truss draws in the jacking system on the slip truss.

26. method as claimed in claim 24 further comprises and uses the jacking system be installed on the sliding beam to draw sliding beam and sliding beam is discharged to step on a plurality of barges.

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