Pipelaying Vessel

Abstract

There is disclosed a variety of arrangements for laying of rigid pipe from reeled storage and/or on-board welding fabrication. Thirteen independent aspects of the invention are identified. In one particular arrangement ( FIGS. 3 a -3 b ), a tilting lay tower ( 106 ) having two travelling clamps ( 210, 220 ) is provided centrally on a pipelay vessel with a radius control arch ( 140 ) pivotable to receive rigid pipe from either port or starboard lay paths. A vertical axis reel or carousel ( 104 ) is provided, within an arrangement of curved take-off arms ( 130, 134 ) and a large radius curved wall ( 128 ). By these means, pipe can be loaded onto the carousel either clockwise or anti-clockwise, and can be supplied to the lay tower via the port or starboard lay path. Continuous rigid product fabricated by a selection of welding lines ( 112, 114, 116 ) at the port side can be guided around the large radius wall either for reeling onto the carousel or for direct feeding to the lay tower. A stinger 110 at the starboard side can be used for on-loading of prefabricated pipe. A pipe elevator ( 150 ) can erect larger pipe stalks (double- or quad-joints) from deck level for welding within the tower. Flexible product can be stored within an inner compartment ( 1042 ) of the carousel and laid via the same tower. The vessel may be a reversible conversion of a FPSO.

1 . A sea-going vessel having pipe launching apparatus for laying continuous elongate product, the pipe launching apparatus comprising:
 first product supply apparatus arranged substantially at deck level for supplying continuous elongate product into a first path along a deck at one side of the vessel;   second product supply apparatus arranged substantially at deck level for supplying continuous elongate product into a second path along deck at the opposite side of the vessel;   a tower structure mounted substantially on the vessel centreline and inclinable to a desired launch angle to align with a catenary curve of said product suspended below the vessel;   pipe handling means within said tower structure operable to receive said product at a central elevated position for gripping and supporting the weight of the suspended product while paying it out; and   tower diverter means operable for receiving said product from deck level at one of two side elevated positions above said first path or said second path respectively according to whichever production apparatus is being used, and for supporting the product in a curved path from the side elevated position to said central elevated position and aligning it with said launch angle.   
   
   
       2 . A sea-going vessel as claimed in  claim 1 , wherein said first product supply apparatus includes at least one pipeline production facility for receiving sections of rigid pipe and joining them to produce said continuous product for supply directly to said pipe handling means via said first path. 
   
   
       3 . A sea-going vessel as claimed in  claim 2 , wherein an alternative production facility for a different process is arranged in parallel, on a deck above the other. 
   
   
       4 . A sea-going vessel as claimed in  claims 2  or  3 , wherein said pipeline production facility is arranged toward the opposite side of the vessel from said first path and anti-parallel thereto, the product being diverted through a 180° curved path into said first path and thence to the tower diverter. 
   
   
       5 . A sea-going vessel as claimed in  claim 4 , wherein said second product supply apparatus includes the same pipeline production facility operable to supply continuous product onto a storage carousel via substantially the same curved path in a first phase of operation and then in a second phase of operation to unload the stored product via said 180° curved path substantially in reverse and thus into said second path and thence to the tower diverter. 
   
   
       6 . A sea-going vessel as claimed in  claim 4 , wherein said 180° curved path is defined by a diverter structure partially surrounding said carousel. 
   
   
       7 . A sea-going vessel as claimed in claim, wherein said first product supply apparatus includes a horizontal pipe storage carousel for storing a length of pre-fabricated continuous product, the carousel being operable to unload said product into said first path and thence to the tower diverter. 
   
   
       8 . A sea-going vessel as claimed in  claim 7 , wherein said carousel is operable as part of said first product supply apparatus and as part of said second product supply apparatus, according to its direction of rotation during unloading. 
   
   
       9 . A sea-going vessel as claimed in  claim 8 , wherein said carousel is arranged to be loadable from an on-board pipeline production facility and alternatively from an off-board supply, the direction of rotation during unloading being different according to the source of supply. 
   
   
       10 . A sea-going vessel as claimed in  claim 9 , wherein a loading stinger is provided on the vessel for receiving pipe from said off-board supply. 
   
   
       11 . A sea-going vessel as claimed in  claim 7 , wherein said carousel is substantially surrounded by a large radius diverter structure, the product being diverted from storage on the carousel around the outside of this structure whether serving as part of the first or second production apparatus. 
   
   
       12 . A sea-going vessel as claimed in claim, wherein said pipe launching apparatus further includes first and second vertical radius controllers mounted at deck level for receiving the product and diverting the product upward from said first path and said second path respectively toward said tower diverter means. 
   
   
       13 . A sea-going vessel as claimed in  claim 12 , wherein said first and second vertical radius controllers include common components, these being transferable from the one side of the vessel to the other side of the vessel according to which production apparatus is being used. 
   
   
       14 . A sea-going vessel as claimed in  claim 12 , wherein said first and second vertical radius controllers are mounted for fore-and-aft movement to adjust their position according to the inclination of the tower structure. 
   
   
       15 . A sea-going vessel as claimed in  claim 12 , wherein said pipe launching apparatus further comprises a straightener associated with each vertical radius controller for removing a plastic bending introduced by the vertical radius controllers. 
   
   
       16 . A sea-going vessel as claimed in  claim 15 , wherein said straightener is mounted on a pivoting arm adjustable according to the inclination of the tower structure. 
   
   
       17 . A sea-going vessel as claimed in claim, wherein said tower diverter means comprises a radius controller mounted on the tower above said elevated position and movable between port and starboard operating positions for receiving said product at a side elevated position above whichever of said first path or said second path is appropriate. 
   
   
       18 . A sea-going vessel as claimed in  claim 17 , wherein said radius controller is movable between said port and starboard positions by swinging it in an arc about a lay axis of the pipe handling means. 
   
   
       19 . A sea-going vessel as claimed in  claims 18  or  19 , wherein said tower diverter means further comprises a straightener supported so as to move together with the radius controller. 
   
   
       20 . A sea-going vessel as claimed in any of  claim 17 , wherein said radius controller is further operable at a central position for receiving elongate article from a central product supply apparatus at deck level. 
   
   
       21 - 104 . (canceled)