An accessory installation pallet for handling an accessory on an offshore vessel includes a pallet frame and multiple pivotable deck sections. The pallet frame provides the pallet with structural rigidity and is provided with fixating devices for securing an accessory, e.g. a PLET, to the pallet. The pallet frame is furthermore provided with one or more coupling devices adapted to couple the pallet with a PLET handler, to allow the PLET handler to pivot the pallet from a horizontal transport position into an upright support position. The pivotable deck sections are pivotable mounted in the pallet frame, such that each deck sections can pivot between a folded position, in which the deck section is located adjacent the pallet frame, and an extended position, in which the deck section extends in a direction away from the pallet frame.

An accessory installation pallet for handling an accessory on an offshore vessel includes a pallet frame and multiple pivotable deck sections. The pallet frame provides the pallet with structural rigidity and is provided with fixating devices for securing an accessory, e.g. a PLET, to the pallet. The pallet frame is furthermore provided with one or more coupling devices adapted to couple the pallet with a PLET handler, to allow the PLET handler to pivot the pallet from a horizontal transport position into an upright support position. The pivotable deck sections are pivotable mounted in the pallet frame, such that each deck sections can pivot between a folded position, in which the deck section is located adjacent the pallet frame, and an extended position, in which the deck section extends in a direction away from the pallet frame.

A drilling marine riser section comprises a main riser pipe with radially extending flanges and multiple auxiliary pipes at least comprising a choke line and a kill line. One or more clamps retain the auxiliary pipes. Further the riser section has buoyancy members. The choke line and the kill line are connected to each of the flanges in a tensile load sharing arrangement, so thatin vertical use orientation of the riser section in a riser stringweight stress is distributed in the main riser pipe and the choke line and the kill line. The buoyancy members form an exterior of the riser section including diametrically opposed and parallel flat bottom and top stacking faces relative to the axis of the main riser pipe, allowing stacking of riser sections in horizontal orientation. The choke line and the kill line are arranged diametrically opposite from one another and between the flat bottom and top stacking faces.

A deepwater hoisting system includes a synthetic fibre rope winch assembly including a motor driven first winch and a length of synthetic fibre rope driven by said first winch. The synthetic fibre rope has an end remote from the first winch. The system further includes a steel wire winch assembly including a motor driven second winch and a length of steel wire driven by said second winch. The steel wire has an end remote from the second winch. At least the second winch is an active heave compensation motor driven winch. The system further includes a lifting block having a lifting block sheave, through which the synthetic fibre rope is run. The end of the synthetic fibre rope is connected to the end of the steel wire, so that the lifting block is suspended in a double-fall arrangement.

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).

The invention provides a modular system for use in an offshore pipelay operation, and apparatus and a method of use. The system comprises a plurality of pipe storage modules, each comprising a rack for accommodating a plurality of pipeline sections. The pipe storage modules are configured to be assembled together to form an integrated structure on a deck of a vessel.

The invention provides a modular system for use in an offshore pipelay operation, and apparatus and a method of use. The system comprises a plurality of pipe storage modules, each comprising a rack for accommodating a plurality of pipeline sections. The pipe storage modules are configured to be assembled together to form an integrated structure on a deck of a vessel.

A marine reel lay method pipeline installation system for laying a flexible pipeline on the seabed a pipeline includes a pipeline launch tower adapted to launch the flexible pipeline in a firing line along said tower; a pipeline guide provided at an elevated position; one or more tensioners, wherein the tensioner frame includes two frame segments with track units, the two frame segments being adapted to be conjoined to each other and being pivotably mounted to said pipeline launch tower about a respective vertical tensioner pivot axis, allowing said two frame segments to be pivotable between a closed flexible pipeline laying configuration; and an open configuration; one or more vertical trolley rails supported by said pipeline launch tower and positioned between said vertical tensioner pivot axes of said two frame segments; a trolley movable along said one or more vertical trolley rails in a vertical trolley path which is unobstructed when said two frame segments are in the open configuration; and a hoisting device being adapted to lower and raise said trolley.

A marine reel lay method pipeline installation system for laying a flexible pipeline on the seabed a pipeline includes a pipeline launch tower adapted to launch the flexible pipeline in a firing line along said tower; a pipeline guide provided at an elevated position; one or more tensioners, wherein the tensioner frame includes two frame segments with track units, the two frame segments being adapted to be conjoined to each other and being pivotably mounted to said pipeline launch tower about a respective vertical tensioner pivot axis, allowing said two frame segments to be pivotable between a closed flexible pipeline laying configuration; and an open configuration; one or more vertical trolley rails supported by said pipeline launch tower and positioned between said vertical tensioner pivot axes of said two frame segments; a trolley movable along said one or more vertical trolley rails in a vertical trolley path which is unobstructed when said two frame segments are in the open configuration; and a hoisting device being adapted to lower and raise said trolley.