Cantilever system and method of use

• US 8,287,212 B2
• Filed: 03/04/2011
• Issued: 10/16/2012
• Est. Priority Date: 03/04/2011
• Status: Active Grant

• Current Assignee: ENSCO International Incorporated (Valaris Ltd.)
• Original Assignee: Ensco PLC
• Inventors: Roper, Richard R.
• Primary Examiner(s): LAGMAN, FREDERICK LYNDON
• Application Number:
  US13/041,185
• Publication Number:
  US 20120224925A1
• Time in Patent Office: 592 Days
• Field of Search: 405/195.1, 405/201, 405/196, 405/197, 405/198, 405/199, 405/200
• US Class Current: 405/201
• 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 17/021 with relative movement between supporting construction and platform
• CPC Class Codes: E02B 2017/006 with lattice style supporting legs

Abstract

A cantilever system for a rig comprising a hull, a beam coupled to the hull, an extension member coupled to the beam, and a hold-down member spaced from a support member and coupled to the extension member. A first end of the beam is extendable over an edge of the hull while a second end of the beam is positioned on the hull. The extension member increases the longitudinal length of the beam. The support member is disposed adjacent the edge of the hull. The hold-down member is configured to apply a force to the extension member in a direction toward the hull when the first end of the beam is extended over the edge of the hull. A method of increasing the capacity of the cantilever system comprises increasing the spacing between the support member and the hold-down member.

Claims

1. A cantilever system for a rig, comprising:

a hull;

a beam movably coupled to the hull, wherein a first end of the beam is extendable over an edge of the hull while a second end of the beam is positioned on the hull;

an extension member coupled to the second end of the beam, wherein the extension member increases the longitudinal length of the beam; and

a passive hold-down member that is spaced apart from a support member to increase a maximum load that the beam supports without reducing a maximum reach of the beam from the edge of the hull, wherein the hold-down member is configured to apply a reactive force to the extension member in a direction toward the hull when the first end of the beam is extended over the edge of the hull and a second hold-down member positioned between the support member and the hold-down member that is coupled to the extension member, wherein the second hold-down member is configured to apply a force to the beam in a direction toward the hull when the first end of the beam is extended over the edge of the hull, and wherein the second hold-down member is coupled to the second end of the beam adjacent to a connection between the extension member and the second end of the beam.

2. The system of claim 1, wherein the beam is an I-beam.

3. The system of claim 1, further comprising a plurality of legs configured to support the hull, wherein the hull is moveable relative to the legs.

4. The system of claim 1, wherein the support member is disposed adjacent the edge of the hull.

5. The system of claim 1, wherein the support and hold-down members are pre-installed in the hull.

6. The system of claim 1, wherein the hold-down member is attachable to the extension member and the hull after the extension member is coupled to the second end of the beam.

7. The system of claim 1, further comprising two or more beams, wherein each beam is coupled to an extension member, a support member, and a hold-down member.

8. A method of increasing a load capacity of a cantilever system that is supported by a hull of a rig, comprising:

extending a portion of a beam of the cantilever system over an edge of the hull;

coupling an extension member to an end of the beam while the portion of the beam is extended over the edge of the hull;

applying a reactive force to the extension member in a direction toward the hull using a passive hold-down member when the portion of the beam is extended over the edge of the hull, wherein the hold-down member is coupled to the extension member; and

increasing a spacing between the hold-down member and a support member to increase a maximum load that the beam supports without reducing a maximum reach of the beam from the edge of the hull;

securing a second hold-down member to the beam at a position between the support member and the hold-down member that is coupled to the extension member; and

applying a force to the beam in a direction toward the hull using the second-hold down member when the portion of the beam is extended over the edge of the hull, wherein the second hold-down member is coupled to the end of the beam adjacent to a connection between the extension member and the end of the beam.

9. The method of claim 8, wherein the beam is an I-beam.

10. The method of claim 8, further comprising applying a push force to the beam at a location adjacent to the edge of the hull using the support member.

11. The method of claim 8, further comprising extending a plurality of legs of the rig into a sea floor, and raising the hull relative to the legs.

12. The method of claim 8, further comprising pre-installing the support and hold-down members in the hull.

13. The method of claim 8, further comprising attaching the hold-down member to the extension member and the hull after the extension member is coupled to the end of the beam.

14. The method of claim 8, wherein the cantilever system further comprises two or more beams, wherein each beam is coupled to an extension member, a support member, and a hold-down member.

15. A method of increasing a load capacity of a cantilever system that is supported by a hull of a rig, comprising:

providing a beam that is movably coupled to the hull such that a portion of the beam is extendable over an edge of the hull;

providing an extension member for connection to the beam to thereby increase an overall length of the beam, wherein the beam has a maximum reach that it may be extended from the edge of the hull when the extension member is coupled to the beam;

providing a passive hold-down member to secure the beam and the extension member to the hull;

providing a support member to support the beam on the hull; and

increasing a spacing between the hold-down member and the support member to thereby increase a maximum load that the beam supports when extended to its maximum reach;

securing a second hold-down member to the beam at a position between the support member and the hold-down member that is coupled to the extension member; and

applying a force to the beam in a direction toward the hull using the second-hold down member when the portion of the beam is extended over the edge of the hull, wherein the second hold-down member is coupled to the end of the beam adjacent to a connection between the extension member and the beam.