Method and apparatus for the offshore installation of multi-ton packages such as deck packages, jackets, and sunken vessels

• US 5,800,093 A
• Filed: 09/06/1996
• Issued: 09/01/1998
• Est. Priority Date: 03/15/1995
• Status: Expired due to Term

• Current Assignee: Jon E. Khachaturian
• Original Assignee: Jon E. Khachaturian
• Inventors: Khachaturian, Jon E.
• Primary Examiner(s): Dang, Hoang C.
• Application Number:
  US08/709,014
• Time in Patent Office: 725 Days
• Field of Search: 405/204, 405/209, 405/203, 405/196, 114/44, 114/51, 114/50
• US Class Current: 405/204
• CPC Class Codes: B63B 27/16 of lifts or hoists pilot lifts B63B27/146
• CPC Class Codes: B63B 35/003 for transporting very large loads, e.g. offshore structure modules construction methods for artificial islands mounted on piles E02B17/00; for transporting marine vessels B63B35/40; docks B63C1/00
• CPC Class Codes: B63B 77/00 Transporting or installing offshore structures on site using buoyancy forces, e.g. using semi-submersible barges, ballasting the structure or transporting of oil-and-gas platforms
• CPC Class Codes: E02B 17/00 Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor construction methods for floating platforms B63B75/00; anchoring floating platforms B63B21/00; floating platforms, e.g. anchored, B63B35/44; underwater reservoirs B65D88/78
• CPC Class Codes: E02B 2017/0047 using a barge
• CPC Class Codes: E02B 2017/0052 Removal or dismantling of offshore structures from their offshore location

Abstract

A method and apparatus for the installation or removal of large multi-ton prefabricated deck packages includes the use of usually two barges defining a base that can support a large multi-ton load. A variable dimensional truss assembly is supported by the barge and forms a load transfer interface between the barge and deck package. Slings are suspended from a compression frame portion at the boom end portions of the truss assembly. The slings form attachments between the compression frame and the deck package at the upper elevational positions on the deck package. Tensile connections form attachments between the deck package and barge at a lower elevational position. The variable dimension truss includes at least one member of variable length, in the preferred embodiment being a winch powered cable that can be extended and retracted by winding and unwinding the winch.

Claims

1. A lifting apparatus for lifting a multi-ton package such as a deck package, sunken vessel, or offshore jacket, comprising:

a) a pair of barges, each defining a base that can support a plurality of diagonally extending lift booms pivotally mounted thereon and a large multi-ton load;

b) a truss supported by the barges about the periphery of the package for forming a load transfer between the barges and the package to be lifted;

c) said truss including at least one compression frame member supported by the plurality of diagonally extending lift booms, each lift boom having a lower end attached to a barge and an upper end that can be attached to the compression frame member;

d) a plurality of cables that depend from the combination of truss and compression member, the cables having lower ends for holding the package; and

f) the combination of the compression frame and booms enabling the cables to raise and lower the package.

2. The apparatus of claim 1 wherein the truss is a variable dimension truss means that includes booms and variable length truss members each spanning between two booms on opposing sides of the package.

3. The apparatus of claim 2 wherein there are two lifting booms and the barges have horizontal surfaces spaced generally on opposite sides of the package being lifted, each barge supporting a boom during lifting.

4. The apparatus of claim 1 wherein the truss is a variable dimension truss that includes two opposing truss members that are each pinned to a different one of the barges and which are angularly disposed with respect to each other during use, wherein caps form a detachable interface between the truss members and the compression frame member.

5. The apparatus of claim 1 wherein the truss includes a winch operated cable.

6. The apparatus of claim 4 wherein the variable dimension truss means includes a winch operating a cable.

7. The apparatus of claim 1 wherein each boom is an "A" frame shaped boom that comprises a pair of longitudinal boom members that form an acute angle, a pair of padeye members that form a detachable interface between each longitudinal boom member and a barge, a free end portion having a structural member with a projection thereon and a pair of end caps that form a detachable connection between the longitudinal boom members and the compression member.

8. The apparatus of claim 2 wherein the variable length members includes multiple winch and cable assemblies spaced along the upper deck surface of each barge.

9. A method for the offshore lifting of a multi-ton package such as a deck package, sunken vessel or jacket, comprising the steps of:

a) transporting a lifting assembly to a desired site of the package;

b) attaching a lifting assembly to the package at multiple positions including positions that are at least on generally opposite sides of the package, the lifting assembly including at least three chords, including a horizontal chord normally in tension during the lifting process which has a variable length and a diagonally extending chord normally in compression during the lifting process;

c) wherein in step "a" the lifting assembly includes two opposed lifting booms connected by at least one compression frame member that spans between upper end portions of the booms, a plurality of slings with end portions that respectively attach to the combination of booms and compression frame member;

d) structurally supporting the lifting assembly with one or more lift barges;

e) supporting the package with the slings; and

f) lifting the package by changing the length of the horizontal chord of the lifting assembly.

10. The method of claim 9, wherein the package can be lowered by lengthening the horizontal chord.

11. The method of claim 9, wherein the lifting assembly can raise or lower the package once suspended below and supported by the slings.

12. The method of claim 10, wherein the horizontal chord includes a winch that is wound with a lift cable which winds/unwinds to change the length of the lift cable.

13. The method of claim 9, wherein there are two opposed lift barges that are floating barges.

14. The method of claim 9, wherein one portion of the lifting assembly includes a plurality of compression carrying diagonally extending lift booms, each with opposing end portions and a plurality of end caps that removably attach to the end portions wherein two of the end caps form a pinned connection with the compression member.

15. The method of claim 14, wherein each lift barge has a winch structurally mounted thereon and a lower connection formed with the package includes a flexible cable extending between the winch and the package.

16. The method of claim 15, wherein the lifting assembly includes a plurality of non-extensible diagonally extending lift booms, each removably connecting to an end cap and further comprising steps of connecting a plurality of the end caps to the compression member, and further comprising the step of connecting the booms to the end caps.

17. A method for the offshore lifting a multi-ton package such as a deck package, jacket or submerged vessel, comprising the steps of:

a) transporting a lifting assembly to a desired site having the package;

b) attaching the lifting assembly to the package at multiple elevational positions on the package, including upper and lower positions that are at least on generally opposite sides of the package;

c) wherein the lifting assembly includes opposed floating barges having diagonally extending lifting booms thereon connected at their upper ends by a compression member and horizonal chords that can be varied in length and in step "b" vertical slings are used to attach the upper end portion of each of the diagonally extending lifting booms at the compression member to the package;

d) structurally supporting each of the lifting booms at the lower end portion thereof with one of the barges, each boom being pivotally attached to its barge;

e) wherein the package is supported by the slings depending from the upper end of the booms and the slings attaching to the package; and

f) elevating the package by changing the length of the horizontal chord of each lifting assembly.