A line laying and/or recovering method in a body of water that includes providing a laying device including two facing upstream grippers and two facing downstream grippers, defining a passage for the circulation of the line; lowering the line to at least one stop position; stopping the line in the at least one stop position; and, prior to the at least one stopping of the line in the stop position, limited downward overrun past the stop position to a change of direction position; time delay in the change of direction position; limited raising of the line from the change of direction position to the stop position.

A line laying and/or recovering method in a body of water that includes providing a laying device including two facing upstream grippers and two facing downstream grippers, defining a passage for the circulation of the line; lowering the line to at least one stop position; stopping the line in the at least one stop position; and, prior to the at least one stopping of the line in the stop position, limited downward overrun past the stop position to a change of direction position; time delay in the change of direction position; limited raising of the line from the change of direction position to the stop position.

A method including at least one phase of near-immobilization or immobilization of the line, including the following steps: activation of the motor of at least one upper tensioner and/or of at least one lower tensioner by a control unit, in order to apply to the movement member of the upper tensioner and/or of the lower tensioner, a holding torque to hold the line against its weight; at least occasional control by the control unit of at least one motor of an upper tensioner and/or of a lower tensioner for causing a movement member of the upper tensioner and/or lower tensioner to move or for changing the holding torque applied to the movement member of the upper tensioner and/or of the lower tensioner.

A method including at least one phase of near-immobilization or immobilization of the line, including the following steps: activation of the motor of at least one upper tensioner and/or of at least one lower tensioner by a control unit, in order to apply to the movement member of the upper tensioner and/or of the lower tensioner, a holding torque to hold the line against its weight; at least occasional control by the control unit of at least one motor of an upper tensioner and/or of a lower tensioner for causing a movement member of the upper tensioner and/or lower tensioner to move or for changing the holding torque applied to the movement member of the upper tensioner and/or of the lower tensioner.

There is provided a method of interconnecting a conduit and a plurality of subsea structures. The method comprises providing a first manifold header in-line of the conduit, where the first manifold header has at least one valve installed therein, A portion of the conduit is lowered to the sea bed such that the first manifold header is engaged with a first subsea structure, and a further portion of the conduit is lowered to the sea bed. A second manifold header, having at least one valve installed therein, is provided in-line of the conduit and engaged with a second subsea structure. The length of conduit provided on the sea bed between the first subsea structure and the second subsea structure is significantly greater than the distance between the first and second subsea structures.

There is provided a method of interconnecting a conduit and a plurality of subsea structures. The method comprises providing a first manifold header in-line of the conduit, where the first manifold header has at least one valve installed therein, A portion of the conduit is lowered to the sea bed such that the first manifold header is engaged with a first subsea structure, and a further portion of the conduit is lowered to the sea bed. A second manifold header, having at least one valve installed therein, is provided in-line of the conduit and engaged with a second subsea structure. The length of conduit provided on the sea bed between the first subsea structure and the second subsea structure is significantly greater than the distance between the first and second subsea structures.

A pipelay vessel having two pipe string manufacturing lines and a firing line, wherein the pipe string manufacturing lines are designed for simultaneously handling two different pipe outer diameters for use as an inner pipe and an outer pipe respectively. Further, the vessel has a pipe-in-pipe assembly workstation for assembling the inner pipe and the outer pipe in a pipe-in-pipe configuration. The vessel is designed with a lay-out which allows for producing offshore pipe-in-pipe strings from single joints, wherein available space is optimally used and pipe-in-pipe strings can be produced safely offshore.

A pipelay vessel having two pipe string manufacturing lines and a firing line, wherein the pipe string manufacturing lines are designed for simultaneously handling two different pipe outer diameters for use as an inner pipe and an outer pipe respectively. Further, the vessel has a pipe-in-pipe assembly workstation for assembling the inner pipe and the outer pipe in a pipe-in-pipe configuration. The vessel is designed with a lay-out which allows for producing offshore pipe-in-pipe strings from single joints, wherein available space is optimally used and pipe-in-pipe strings can be produced safely offshore.

A guide structure is provided for guiding deployment of a pipeline from a hang-off structure through an opening in a vessel during a J-lay operation. The guide structure comprises a port-side guide assembly and a starboard-side guide assembly for engaging and guiding the pipeline below the hang-off structure, wherein the port and star-board-side guide assemblies are independently moveable to engage and guide the pipeline. The guide assemblies may be mounted to traverse on rails provided within the opening.

A guide structure is provided for guiding deployment of a pipeline from a hang-off structure through an opening in a vessel during a J-lay operation. The guide structure comprises a port-side guide assembly and a starboard-side guide assembly for engaging and guiding the pipeline below the hang-off structure, wherein the port and star-board-side guide assemblies are independently moveable to engage and guide the pipeline. The guide assemblies may be mounted to traverse on rails provided within the opening.