Pipe laying vessel and method
AssigneeCoflexip Stena Offshore Limited
InventorsRobert George Martin, Donald Carmichael, Stephen John Roberts
Life of this patent
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Abstract
Methods and apparatus for laying marine pipelines of the type in which the pipeline is assembled along a horizontal axis on board a pipe laying vessel prior to being launched therefrom; in which the pipeline is plastically bent to a desired launch angle and, in most cases, at least partially straightened thereafter. In preferred embodiments, the pipeline is bent through an angle greater than 90.degree.. In the most preferred embodiments, the pipeline is diverted, initially upwardly, through an angle of substantially 180.degree. sheave (28), prior to being bent downwards to the desired launch angle by an adjustable angle ramp (30). Other variations are also described.
Claims25
A method of laying an underwater pipeline, comprising assembling pipe sections together along a substantially horizontal axis on the deck of a vessel to form a pipeline and laying the pipeline onto the sea bed as pipeline assembly progresses, bending the pipeline as it is laid from the vessel, wherein the bending of the pipeline includes diverting the pipeline upwardly along a substantially arcuate path and subsequently diverting the pipeline downwardly to a final launch angle and launching the pipeline from the vessel.
A vessel for use in laying an underwater pipeline, the vessel including a deck area, means on the deck area for aligning pipe sections along a substantially horizontal axis and connecting said pipe sections together to form a pipeline, and means for bending the pipeline to cause it to pass from said horizontal axis to a launch axis having a substantial inclination to the horizontal;
- in which said bending means is adapted to bend said pipeline upwardly along a substantially arcuate path and subsequently to bend said pipeline downwardly to a final launch angle.
Dependencies are inferred from the claim text.