A method of connecting cables of a unitary pipe section that is to be assembled vertically to an undersea fluid transport pipe, by positioning around a low end of the unitary pipe section (40) a female annular connector (2) having connected thereto cables (14) extending along the unitary pipe section; positioning around a high end of the pipe (42) a male annular connector (24) having connected thereto cables (32) extending along the pipe; and connecting together the male and female connectors by sliding them vertically towards each other while assembling the unitary pipe section on the pipe.

A method of connecting cables of a unitary pipe section that is to be assembled vertically to an undersea fluid transport pipe, by positioning around a low end of the unitary pipe section (40) a female annular connector (2) having connected thereto cables (14) extending along the unitary pipe section; positioning around a high end of the pipe (42) a male annular connector (24) having connected thereto cables (32) extending along the pipe; and connecting together the male and female connectors by sliding them vertically towards each other while assembling the unitary pipe section on the pipe.

A method of installing a subsea pipeline having a direct tie-in to a subsea structure includes landing an end of a pipeline onto a pipeline landing frame, the pipeline landing frame being on a surface of a subsea structure, the pipeline landing frame providing a location for landing the end of the pipeline before connection to a connection point of the subsea structure; subsequently lowering the pipeline end; and connecting the pipeline end to a connection point of the subsea structure. A pipeline landing frame for implementing the method is also described.

A method of installing a subsea pipeline having a direct tie-in to a subsea structure includes landing an end of a pipeline onto a pipeline landing frame, the pipeline landing frame being on a surface of a subsea structure, the pipeline landing frame providing a location for landing the end of the pipeline before connection to a connection point of the subsea structure; subsequently lowering the pipeline end; and connecting the pipeline end to a connection point of the subsea structure. A pipeline landing frame for implementing the method is also described.

A method of laying an off-shore pipeline (1) comprises: installing on the seabed (3) a fixed receiving structure (4) having a redirecting device (5), paying-out from a laying vessel (7) a pipeline (1) with the pipeline end termination device (9) vertically towards the seabed (3), extending a damping cable (6) from the pipeline end termination device (9) through the redirecting device (5) to an underwater damping buoy (14), connecting an underwater suspension buoy (15) to the pipeline end termination device (9), inclining the pipeline (1) from a vertical orientation towards the horizontal orientation, using: the suspension buoy (14) to counterbalance at least part of the weight of the pipeline end termination device (9), the damping buoy (14) for damping the pipeline (1).

A method of laying an off-shore pipeline (1) comprises: installing on the seabed (3) a fixed receiving structure (4) having a redirecting device (5), paying-out from a laying vessel (7) a pipeline (1) with the pipeline end termination device (9) vertically towards the seabed (3), extending a damping cable (6) from the pipeline end termination device (9) through the redirecting device (5) to an underwater damping buoy (14), connecting an underwater suspension buoy (15) to the pipeline end termination device (9), inclining the pipeline (1) from a vertical orientation towards the horizontal orientation, using: the suspension buoy (14) to counterbalance at least part of the weight of the pipeline end termination device (9), the damping buoy (14) for damping the pipeline (1).

A method for burying a pipeline in a bed of a body of water which includes: making a trench with a bottom surface in a bed of a body of water via a bed working vehicle advanced in an advancing direction; advancing a floating unit in the body of water; releasing a pipeline in the body of water via a tensioner and along a lay device tilted in an adjustable manner and constrained to the floating unit; guiding the pipeline to the bottom surface of the trench via a guide vehicle advanced on the bed of the body of water; and controlling the tensioner, the floating unit, the lay device, the bed working vehicle, and the guide vehicle to minimize stress along the pipeline.

A method for burying a pipeline in a bed of a body of water which includes: making a trench with a bottom surface in a bed of a body of water via a bed working vehicle advanced in an advancing direction; advancing a floating unit in the body of water; releasing a pipeline in the body of water via a tensioner and along a lay device tilted in an adjustable manner and constrained to the floating unit; guiding the pipeline to the bottom surface of the trench via a guide vehicle advanced on the bed of the body of water; and controlling the tensioner, the floating unit, the lay device, the bed working vehicle, and the guide vehicle to minimize stress along the pipeline.

A pipe-laying vessel including a pipe-laying tower extending upwardly from the vessel, the tower including a first lower section extending upwardly from a proximal end to a distal end above the main deck of the vessel, and a second upper section movably mounted on the first lower section, and the tower having a first pipe-laying configuration for laying pipeline P in which the upper section is positioned above the lower section and pipe is passed from the upper section to the lower section when, in use, it is being laid, and a second stowed configuration in which the second upper section is moved relative to the lower section and the overall height of the tower is reduced.

A pipe-laying vessel including a pipe-laying tower extending upwardly from the vessel, the tower including a first lower section extending upwardly from a proximal end to a distal end above the main deck of the vessel, and a second upper section movably mounted on the first lower section, and the tower having a first pipe-laying configuration for laying pipeline P in which the upper section is positioned above the lower section and pipe is passed from the upper section to the lower section when, in use, it is being laid, and a second stowed configuration in which the second upper section is moved relative to the lower section and the overall height of the tower is reduced.