WO2002057675B1

WO2002057675B1 - Apparatus and method for the laying of elongate articles

Info

Publication number: WO2002057675B1
Application number: PCT/GB2002/000200
Authority: WO
Inventors: Thomas Gibson Welsh
Original assignee: Stolt Offshore Ltd; Thomas Gibson Welsh
Priority date: 2001-01-22
Filing date: 2002-01-18
Publication date: 2002-11-14
Also published as: GB0316591D0; GB0101516D0; GB2387213A; WO2002057675A1

Abstract

There is disclosed improved apparatus and method for laying articles (pipes, cables) on the sea-bed. A radius controller (12) and a track tensioner (14) are supported above the deck, defining a laying path such that the article (100) passes over the radius controller then downwardly through the tensioner to enter the sea in a predetermined entry region, the tensioner supporting the weight of the article between the vessel and the sea bed. To improve access to the base of a vessel's vertical lay system (5) and to any elongate article (100) being laid, the tensioner laying path is inclined at an angle to the vertical so that the tensioner can be located away from the entry region. Guides (15, 16) support the article at the points between the tensioner and the entry region to avoid interference of the article with the vessel. The guides are independently retractable to allow passage of larger modules.

Claims

AMENDED CLAIMS[received by the International Bureau on 26 July 2002 (26.07.02); original claim 1 replaced by amended claim 1 (3 pages)]

1. Apparatus for laying elongate articles on the sea-bed from a vessel, which apparatus includes a radius controller and, at least one track tensioner supported above the deck of the vessel, the apparatus defining a laying path such that during laying an elongate article passes over the radius controller and then downwardly through the tensioner to enter the sea in a predetermined entry region relative to the vessel, the tensioner supporting the weight of the elongate article between the vessel and the sea bed, wherein the path defined through the tensioner for laying is inclined at an angle to the vertical and the tensioner is located away from a point directly above said entry region, and wherein the apparatus further includes first and second guide means moveable independently of one another in the plane of inclination of the laying path between retracted and engaged positions with respect to the elongate article being layed, each guide means being adapted for supporting the elongate article at a point between the tensioner and the entry region to avoid interference of the elongate article with the vessel.

2. Apparatus as claimed in claim 1, wherein the radius controller and the tensioner are located in a tower.

3. Apparatus as claimed in claim 1 or claim 2, wherein the tower has an open framework or lattice structure and the inclination of the lay path and the location of the tensioner away from the vertical is sufficient to allow the side and top of the tower to be exposed, and thereby open up access for the cranes and other lifting equipment on the vessel to the interior of the tower.

4. Apparatus as claimed in any preceding claim, wherein the two guide means can be independently retracted and engaged to the elongate article being laid in turn, to allow passage of the crane or working on the elongate article.

5. Apparatus as claimed in any preceding claim, wherein the tower is located on the deck of the vessel adjacent to a moonpool so that there is minimum overlay of the tower over the moonpool. 15

6. Apparatus as claimed in any one of claims 1 to 4, wherein the tower is located to overhang the side of a vessel.

7. Apparatus as claimed in any one of the preceding claims, wherein the guide means, or at least one of them, comprises a guide track arrangement so as to present a support surface which moves with the elongate article as it is laid.

S. Apparatus as claimed in claim 7, wherein the guide track arrangement(s) comprise a short arcuate section with articulated track running over the surface of the arcuate section.

9- Apparatus as claimed in any of the preceding claims, wherein one guide means is located above deck and a second guide means is located below the height of the deck.

10. Apparatus as claimed in claim 9, wherein, one of the guide means is located below the tensioner but within the confines of the tower and the second guide track located below the height of the deck within the moonpool or over the vessel side,

11. Apparatus as claimed in any one of the preceding claims, wherein each of the guide means is mounted with hydraulic ram drive arrangements so that they can be moved independently to engage or disengage the elongate article.

12. Apparatus as claimed in any one of claims 1 to 10, wherein each of the guide means is mounted with pneumatic drive arrangements so that they can be moved independently to engage or disengage the elongate article.

13. Apparatus as claimed in any one of claims 1 to 10, wherein each of the guide means is mounted with electric drive arrangements so that they can be moved independently to engage or disengage the elongate article.

14. A method of laying, elongate articles from a vessel using apparatus located on the deck of the vessel, which apparatus includes a radius controller, at least one track tensioner supported above the deck of the vessel, and first and second guide means, the 16

apparatus defining a laying path for the elongate article that is inclined to the vertical, said first and second guide means being moveable independently in the plane of the of the laying path, wherein the method includes the steps passing the elongate article over the radius controller, and downwardly through the tracks of the tensioner, and into the sea in a predetermined entry, independently moving the guide means to engage the elongate article and guide the elongate article during laying so that it does not interfere with the vessel.