Abstract: When laying pipe from a pipelay vessel into the sea, the pipe is subject to torsion. To relieve this torsion an apparatus to perform controlled relative rotation between the pipe and the vessel is proposed, which apparatus is also able to permit the pipelay vessel to “weather vane” about the pipe without twisting it. The apparatus comprises a hold off clamp (3) which is mounted within a housing (5) via thrust bearings (4). The housing (5) is mounted to the vessel (6), and the clamping means (3) is clamped to the pipe (1). A brake assembly (12) and a drive means (13) capable of providing predetermined rotation and torsional damping, enable controlled relative rotation of the clamping means within the housing. With the pipe secured in the clamping means controlled relative rotation can be achieved for torsion relief, or weather vaning of the pipelay vessel about the pipe can be achieved.

Abstract: When laying pipe from a pipelay vessel into the sea, the pipe is subject to torsion. To relieve this torsion an apparatus to perform controlled relative rotation between the pipe and the vessel is proposed, although it is also applicable to performing controlled relative rotation for other purposes, such as joint alignment. The pipe is secured in securing means, such as clamping means, adapted to support the weight of the pipe. The clamping means are mounted to the vessel via a mounting means, adapted to provide the controlled relative rotation and comprising a turntable, a brake assembly, a drive means and a thrust bearing, and a vessel support structure such as a vessel structural support trolley or a Top Hat element gripped by a hold off clamp.

Abstract: Disclosed are a method and apparatus for laying down, abandoning and/or recovering a pipe on the sea floor. During lay-down and abandonment, the pipe is lowered by a high capacity winch to an intermediate depth, at which the loading exerted by the pipe has dropped to within the rated capacity of a low capacity winch, to which the loading is then transferred. The high capacity winch line is then recovered to the attendant vessel and the pipe lowered to the sea floor using the low capacity winch. Pipe recovery is essentially a reversal of the above procedure. In this way, the length of the line of the high capacity winch is considerably reduced, which reduces the winch size and hence cost.

Abstract: Disclosed are a method and apparatus for laying down, abandoning and/or recovering a pipe on the sea floor. During lay-down and abandonment, the pipe is lowered by a high capacity winch to an intermediate depth, at which the loading exerted by the pipe has dropped to within the rated capacity of a low capacity winch, to which the loading is then transferred. The high capacity winch line is then recovered to the attendant vessel and the pipe lowered to the sea floor using the low capacity winch. Pipe recovery is essentially a reversal of the above procedure. In this way, the length of the line of the high capacity winch is considerably reduced, which reduces the winch size and hence cost.