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: A method of positioning on the sea floor, from a floating vessel, an unlaid end portion of a pipe that is being laid from its other end on the sea floor is disclosed. The method includes lowering the unlaid end portion of the pipe to a lowered position above the sea floor. Transfer of the load of the unlaid end portion of the pipe occurs from the lowering device to a line for suspending the unlaid end portion of the pipe. Lowering the line for suspending and the unlaid end portion of the pipe occurs. There is disclosed a corresponding method of recovery as well as associated apparatus. A method for effecting a subsea connection between one line and an object suspended below the surface of the sea by another line and associated apparatus are disclosed.

Abstract: Method of positioning on the sea floor, from a floating vessel (100), an unlaid end portion (2) of a pipe that is being laid from its other end on the sea floor, comprising the steps of: (i) lowering the unlaid end portion of the pipe from a lowering device (20) on the vessel to a lowered position in the sea above the sea floor; (ii) transferring the load of the unlaid end portion of the pipe from the lowering device to means (30) for suspending the unlaid end portion of the pipe from the vessel at the lowered position in the sea; and (iii) lowering the means for suspending and the unlaid end portion of the pipe suspended thereby to the sea floor. There is also disclosed a corresponding method of recovery as well as associated apparatus. Further disclosed is a method for effecting a subsea connection between one line and an object suspended below the surface of the sea by another line, and associated apparatus.

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.