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 seal assembly for sealing an annular space between an inner and an outer pipe in a double-walled subsea pipeline which seal assembly comprises an annular member (1) and moveable blocking means (2, 3) and: (a) under normal operating conditions is in a non-sealing position which allows the passage of a gas through said seal assembly; and (b) is actuatable from a non-sealing position to a sealing position in response to the entry of liquid into said annular space.

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 seal assembly for sealing an annular space between an inner and an outer pipe in a double-walled subsea pipeline which seal assembly comprises an annular member (1) and moveable blocking means (2, 3) and: (a) under normal operating conditions is in a non-sealing position which allows the passage of a gas through said seal assembly; and (b) is actuatable from a non-sealing position to a sealing position in response to the entry of liquid into said annular space.