The present invention relates to a marine pipelaying vessel for pipelaying an offshore pipeline by way of the S-lay method and by way of the J-lay method.

To enable the S-lay method, a vessel is provided with an S-lay production line and a stinger.

The S-lay method comprises welding pipe stands together onboard the vessel in the S-lay production line. The S-lay production line is a horizontal production line, i.e. has a ramp with pipe laying equipment that includes apparatus for fabricating pipeline along a fabrication axis which is closer to horizontal than vertical. In such a production line, while being welded together, the pipe stands have a substantially horizontal orientation.

The S-lay production line has a pipeline exit at one end thereof. At the exit, the stinger is mounted, which stinger defines an s-lay firing line. Once the pipe stands are welded to each other and preferably to a seagoing pipeline partially supported on the stinger, the pipe stands are moved in an axial direction out of the production line and onto the stinger. A new set of pipe stands is combined and welded to the previous set of pipe stands. The pipe stands are thus combined into a pipeline.

The pipeline, with one end at the S-lay production line, is thus moved step by step along a curved trajectory towards the sea floor. The production line is provided with pipeline tensioners for retaining the pipeline, and the pipe stands welded to the pipeline, while the pipeline is guided onto the stinger.

The seagoing pipeline is supported by a stinger to control the radius when the pipe bends towards the seabed. The stinger is generally installed at the stern of the vessel and can be an arc having a length of over 120 meters long to keep the bending stress within limits.

Due to the high production rate and the possibility to install concrete coated pipe, S-lay is extremely suitable for pipe installation in shallow and intermediate waters. Larger water depths are also possible but require a relatively long stinger and a large vessel to support it. To enable the J-lay method, a vessel is provided with a J-lay tower and a pipe stand production line. The pipe stand production line differs from the S-lay production line in that it does not combines pipe stands into a continuous pipeline, but into pipe stands. The pipe stands may comprise for example three or four pipe stands and have a length of over 60 meters, for example may have a length of 72 meters.

The J-lay tower defines a J-lay firing line for launching pipeline into the sea by way of the J- lay method. The J-lay tower comprises an upright ramp, for holding pipe stands, and for, at a bottom end of the ramp, supporting an end of a seagoing pipeline. The J-lay firing line extends along the ramp. Typically, pipeline tensioners are provided to support and guide pipe stands and pipeline in and along the firing line.

J-lay is an alternative to the S-lay method for installing rigid pipelines in deep water. With a J- lay system pipe stands are upended and welded to a seagoing pipeline on a near vertical ramp.

Once welded to the seagoing pipeline, the pipe stands are guided into the sea in

substantially vertical direction.

Typically, a J-lay tower is pivotably supported on a vessel, such that the angle at which the pipeline sections are lowered into the sea can be adjusted, so that it is in line with the pipe catenary to the seabed. This way bending of the pipe is kept to a minimum.

The J-lay method is very suitable for deepwater because the pipe leaves the lay system in an almost vertical position and the pipeline is only bent (once) during installation (at the seabed). This reduced amount of bending is beneficial for installing pipelines that are sensitive to fatigue.

An example of a vessel suitable for pipelaying with the S-lay method and the J-lay method is the vessel Seven Borealis. This vessel combines a 600mt S-lay system with a J-lay tower for pipelaying purposes and a 5,000mt Offshore Mast Crane for heavy lifting and deep water construction.

The present invention is concerned with a vessel configured for laying pipeline from by way of the S-lay method and by way of the J-lay method. It is an object of the invention to provide an alternative marine pipelaying vessel for pipelaying an offshore pipeline by way of the S-lay method and by way of the J-lay method, it is a further object of the invention to provide a more efficient marine pipe laying vessel. According to the present invention, there is provided a marine vessel for laying pipeline by way of the S-lay method and by way of the J-lay method, the vessel comprising a stinger configured to supporting a pipe stand to be launched into sea by the J-lay tower, and a pipe stand transfer device, e.g. a crane or pivotable arm, for upending the pipe stand, and for transferring the pipe stand from the stinger to the J-lay tower.

The invention provides a vessel for laying pipeline by way of the S-lay method and by way of the J-lay method according to claim 1.

According to the claimed invention, a marine pipelaying vessel for installing an offshore pipeline by way of the S-lay pipelaying method and by way of a J-lay pipelaying method is provided, the vessel comprising:

- a hull having a stinger end;

- a J-lay tower, which J-lay tower is mounted on the hull of the vessel, the J-lay tower defining a J-lay firing line for launching pipeline into the sea by way of the J-lay method;

- an S-lay production line, comprising one or more welding stations for combining pipeline sections into a pipeline to be launched into sea at the stinger end of the hull using the S-lay method, and one or more tensioners downstream of the one or more welding stations for supporting the weight of the launched pipeline;

- a stinger, which the stinger is mounted, or is mountable, to the vessel at the stinger end thereof and in line with the S-lay production line, and which stinger is configured to receive a pipe stand from the S-lay production line and to support the pipe stand in a pickup position, and

- a pipe stand transfer device, e.g. a crane or pivotable arm, for transferring the pipe stand from the pickup position on the stinger to the J-lay tower.

Thus, with a vessel according to the claimed invention the S-lay production line is used for providing the pipe stands to be launched by the J-lay tower. By providing a stinger configured to support the pipe stand in a pickup position, and a pipe stand transfer device configured to transfer the pipe stand from the stinger to the J-lay tower, pipe stands manufactured in the S- lay production line can be moved out of the S-lay production line via the exit that is also used for launching continuous pipeline by way of the S-lay method. A vessel according to the invention, preferably, has a single production line, which production line can be used for providing pipeline to be launched by way of the S-lay method and for producing pipe stands to be launched by way of the J-lay method. The S-lay production line does not require major changes in lay out and/or set up, such as a lateral exit for moving the pipe stands to a deck mounted pick up position. The latter would increase the footprint of the production line significantly.

Furthermore, the invention allows for using an S-lay production line for providing pipe stands.

It is to be noted that an S-lay production line has a longitudinal layout, to enable parallel welding of multiple pipe sections, the production line extending along the length of the vessel. An exit for launching a continuous pipeline is typically located at one end of the production line and at one end of the vessel. Thus, the welded pipeline sections are moved in an axial direction out of the production line and onto the stinger.

A J-lay production line also has a longitudinal lay out, extending in the longitudinal direction of the vessel. However, the J-lay production line differs from the S-lay production line in that the pipe stands are moved from the production line in a lateral direction, and not in a longitudinal direction, towards a deck located pick up position or pipe stands storage. From the pickup position the pipe stands are subsequently upended and moved into the J-lay firing line of a J-lay tower. These J-lay towers are often mounted to the hull of the vessel halfway a longitudinal side of the hull of the vessel. Thus, the pipe stand can be upended from its deck located pick up position into the firing line.

It is furthermore to be noted that with the S-lay method, the pipeline is launched into sea along a curved trajectory over the stinger, while with the J-lay method pipeline is launched into sea along a straight trajectory.

Therefore, a stinger is typically provided with a curved pipeline guide track, for guiding the pipeline along a curved trajectory towards the sea floor. Furthermore, a stinger is configured such that the pipeline guide track is at the start thereof, i.e. where it receives the pipeline from the production line, at an angle with the horizontal, directing the pipeline towards the sea floor.

A typical s-lay stinger for guiding pipeline towards the seafloor is thus not designed for supporting a pipe stand, which typically extends along a straight longitudinal axis, and not for supporting the pipe stand in a position above the sea surface. Providing a vessel according to the claimed invention with a stinger that is configured to support a pipe stand in a pickup position, and a pipe stand transfer device for transferring the pipe stand from the pickup position on the stinger to the J-lay tower, allows for a single production line to providing both pipeline and pipe stands, the production line having an efficient lay out, and thus allows for an efficient lay out of the vessel, i.e. an optimal use of the space provided by the hull and the deck of the vessel.

The invention thus provides an alternative marine pipelaying vessel for pipelaying an offshore pipeline by way of the S-lay method and by way of the J-lay method. The invention furthermore provides a more efficient marine pipe laying vessel.

In an embodiment, the marine pipelaying vessel according to the invention comprises a stinger that defines, or is able to define, an S-lay firing line for guiding a pipeline in an axial direction from the S-lay production line towards the sea floor by way of the S-lay method. In such an embodiment, the S-lay stinger, more in particular the track of the stinger for guiding pipeline, is suitable for guiding continuous pipeline and for supporting a pipe stand in the pickup position. Thus, there is no need to replace or adapt the stinger when switching between S-lay to J-lay.

In a further embodiment the stinger is provided with features that enhance the use of the stinger in the J-lay process. For example, in an embodiment, the stinger is configured to be supported on a single side only.

For example, in an embodiment, the S-lay stinger is supported on both sides of the pipeline track by drawworks, similar to a draw bridge, to evenly distribute the weight of the stinger and the supported pipeline to the hull of the vessel. When used in the J-lay process, the drawworks on one side are removed to allow access to the pipe stand, that is, to present the pipe stand in a pickup position in which it can be engaged by the pipe stand transfer device. Thus the stinger is supported on both sides during s-lay and is supported on a single side to enable a pipe stand supported on the stinger to be transferred to the J-lay tower by the pipe stand transfer device.

In another embodiment, the stinger is an articulated stinger, comprising multiple hingeable connected stinger sections to provide a curved pipeline trajectory to enable S-lay. When used in the J-lay process, only one or two of the stinger sections are used, and the other sections are removed, providing a truncated stinger for J-lay. The reduction in weight furthermore allows for reducing the support, for example by removing part of the draw works supporting the stinger, and thus improve access to a pipe stand supported by the stinger.

In an alternative embodiment, the stinger is a dedicated pipe stand stinger for receiving the pipe stand from the S-lay production line and for supporting the pipe stand in the pick-up position only, and the vessel furthermore comprises a dedicated S-lay stinger for S-lay use only. In such an embodiment, the dedicated pipe stand stinger can be replaced with the dedicate S-lay stinger. Switching between S-lay and J-lay thus requires replacing the stinger, which takes additional time. However, by providing a dedicated pipe stand stinger, the design of that stinger can be fully directed towards supporting the pipe stand in the pickup position in practice this allows for a relatively light and compact stinger.

In a further preferred embodiment, the dedicated pipe stand stinger and the dedicated S-lay stinger are configured to be mounted on the same mounts. Thus, the same strongpoints in the hull are used, and a hull design for a typical S-lay vessel can be utilised for providing a vessel according to the invention.

In an embodiment of a marine pipelaying vessel according to the invention, the stinger is a dedicated S-lay stinger for S-lay use only, which S-lay stinger is provided with a removable pipe stand support structure that is mountable onto the S-lay stinger to temporarily convert the dedicated S-lay stinger into a dedicated pipe stand stinger for receiving the pipe stand from the S-lay production line and for supporting the pipe stand in the pick-up position.

During s-lay, the pipe stand support structure can be stored on the deck of the vessel. When switching to J-lay, the pipe stand structure is craned onto the stinger. In such an

embodiment, the stinger is, preferably, provided with dedicated mounts for supporting and fixing the support structure to the stinger. In an embodiment, the angle of the stinger also has to be changed, for example by lifting the stinger, to enable the pipe stand support structure to support a pipe stand in a substantially horizontal pick up position. In an alternative design, the pipe stand support structure is configured to be mounted on the S-lay stinger while in the S-lay position, which for example is at an angle with the sea surface. In yet another embodiment, the pipe stand support structure is an adaptable structure, configured to support a pipe stand support track at adjustable heights and/or angles relative to the stinger, to thus enable the pipe stand support track to be adjust to the position and/or angle of the stinger.

In addition or as an alternative, the pips stand support structure is configured to lift and lower the pipe stand support track, for receiving the pipe stand form the S-lay production line in a lowered position and for presenting the pipe stand in the pickup position in a raised stand. Thus, the pipe stand support structure can be used to facilitate access to the pipe stand, for example by lifting the pipe stand from a position between draw works supporting the stinger to a pickup position I which the pipe stand is above the draw works.

In an embodiment, the stinger is an articulated stinger comprising two or more hingeable connected stinger sections.

In an embodiment, the stinger is a hybrid stinger, the stinger comprising at least one pivotably mounted stinger section, that can be moved between an S-lay positon, for supporting pipeline being launched into sea by way of the S-lay method, and a pipe stand support position, for supporting a pipe stand to be launched into sea by way of the J-lay method.

In an embodiment, the stinger is a dual track stinger and has a curved pipe line support track for guiding pipeline towards the seafloor and a substantially straight pipe stand support track for supporting a pipe stand.

In an embodiment, the stinger is a hybrid track stinger, the stinger having a pipeline support track comprising a substantially straight track section, having a length substantially similar to the length of a pipe stand to be launched from the J-lay tower, downstream of the S-lay production line, and, downstream of the straight track section, a curved track section for guiding pipeline towards the seafloor.

In an embodiment, the stinger is a hybrid track stinger, the stinger having a pipeline support track that comprises one or more movable supported track sections and/or multiple support rollers, which one or more track sections and/or multiple support rollers can be moved relative to each other and/or relative to the stinger frame between a first position in which they define a pipeline support track or at least part thereof and a second position in which they define a pipe stand support track.

In an embodiment, the J-lay tower and the pipe stand transfer device are mounted at the stinger end of the vessel, and, preferably, the pipe stand transfer device is mounted between the stinger and the J-lay tower.

In a further embodiment, the pipe stand transfer device is a transfer arm, the transfer arm having multiple grippers, preferably radially extending gripper arms, along its length for engaging the pipe stand, wherein the transfer arm is moveable, preferably is pivotable, between a lowered first position for engaging the pipe stand supported in the pickup position on the stinger, and an upstanding second position for presenting the pipe stand to the J-lay tower, preferably presenting the pipe stand in the J-lay firing line.

In a further embodiment, the transfer arm is configured to move the pipe stand about the longitudinal axis of the transfer arm between a first position and a second position, preferably by pivoting a section of the transfer arm and/or the grippers about a pivot axis parallel to the longitudinal axis of the arm.

In an embodiment, the transfer arm is configured to move the pipe stand along the longitudinal axis of the transfer arm between a first position and a second position, preferably by telescopically extending a section of the transfer arm and/or by pivoting gripper arms about a pivot axis perpendicular to the longitudinal axis of the transfer arm.

Typically, a stinger comprises a frame and a pipeline support track supported by that frame. The stinger frame, preferably, is an articulated stinger frame, comprising multiple hingeable connected stringer frame sections, which can be pivoted relative to each other.

Herein, a hybrid stinger is a stinger that can change between an S-lay configuration and a pipe stand support configuration. For example, by pivoting one or more segments of a segmented stinger between a first and second positon. A hybrid stinger can also comprise a hybrid track, a track comprising one or more track sections that can be moved relative to the stinger frame to adjust the curvature of the track.

Herein, a hybrid track stinger comprises track for guiding pipeline, which track can change between an S-lay configuration and a pipe stand support configuration. The pipeline support track comprises multiple movable supported track sections and/or support rollers, which track sections and/or support rollers can be moved relative to each other and relative to the stinger frame, between a first position in which they define a pipeline support track and a second position in which they define a pipe stand support track.

Herein, a dedicated stinger is a stinger for single use only, for example a dedicated S-lay stinger is configured for S-lay use only. To enable support of a pipe stand requires replacing the dedicated S-lay stinger with another stinger configured for supporting a pipe stand, for example a dedicated pipe stand support stinger, or temporarily adapting the stinger to change its’ function, for example by mounting a pipe stand support structure onto a dedicated S-lay stinger to change it into a dedicated pipe stand support stinger.

In an embodiment, the vessel, more in particular the S-lay production line, is provided with a pipe stand rigger device, configured for moving the, preferably pushing the pipe stand out of the S-lay production line and in the pickup positon on the stinger. In an embodiment, the rigger is embodied as a retractable cradle for supporting the pipe stand. The cradle is pushed onto the stinger and, after the pipe stand is picked up by the pipe stand transfer device, is pulled back into the production line for receiving the next pipe stand.

In a further embodiment, the cradle is configured to also upend the pipe stand. Thus, the pipe stand is presented to the pipe stand transfer device in an upright position the pipe stand transfer device subsequently picks up the pipe stand and transfers it form its position on the stinger to a position in or adjacent to the J-lay firing line.

In a further embodiment, the J-lay tower is located above the S-lay firing line, thus, once the pipe stand has been upended, it has to be transferred over a minimal distance to be moved adjacent or in the J-lay firing line.

In an embodiment, the J-lay tower is located not adjacent the stinger and the S-lay firing line defined by that stinger, but is located above the S-lay firing line such that the J-lay firing line crosses, or nearly crosses the S-lay firing line. In such an embodiment, the J-lay firing line extends through the stinger, and the stinger is configured to allow pipeline to be launched into sea along the j-lay firing line, for example through an opening in the stinger frame.

In a further embodiment, the vessel is provided with a hang of clamp at the lower end of the J-lay firing line for supporting the weight of the launched pipeline when disconnected from the tensioners of the J-lay tower.

In a further embodiment, the hang off clamp is a displaceable hang off clamp, which clamp is displaceable while supporting the weight of the launched pipeline between a first position in which the hang off clamp can be clamped on the pipeline in the S-lay firing line, downstream of the one or more tensioners in the s-lay production line, to allow disconnection of the pipeline from the tensioners and a second position in the J-lay firing line of the J-lay tower such that the pipeline supported by the hang off clamp can be moved between an adjacent s- lay firing line and a J-lay firing line. In an embodiment, the stinger for supporting the pipe stand in the pickup position is provided with a pipe stand storage, configured to hold multiple pipe stands.

In an embodiment, the vessel comprises a mast crane that straddles the S-lay production line and the J-lay tower is located adjacent the mast crane. In a further embodiment, the mast crane is configured such that its’ main hoisting wire can be looped from the top of the mast back into the mast instead of to the top of the jib, and subsequently to the foot of the J- lay tower and into the J-lay tower such that the mast crane hosting wire can also be sued as the J-lay hoisting wire.

In an embodiment, the pipe stand transfer device is a pivotable supported transfer arm, the transfer arm and the J-lay tower are both pivotably mounted on the hull of the vessel, and have a coinciding pivot axis. In an alternative embodiment, the transfer arm is pivotably mounted to the foot of the J-lay tower.

The invention furthermore aims to provide an alternative method of installing pipeline from a vessel by way of the J-lay method.

According to the present invention, there is provided a method of laying pipeline from a vessel by way of the J-lay method, which method includes constructing a pipe stand in the S- lay production line, moving the pipe stand onto a stinger located adjacent the S-lay production line, and transferring the pipe stand from the stinger into the firing line of the J-lay tower.

The invention provides a method of laying pipeline from a vessel by way of the J-lay method according to claim 13.

According to the claimed invention, a J-lay pipelaying method, wherein use is made of a vessel with an S-lay production line, a stinger associated with the S-lay production line, and a J-lay tower defining a J-lay firing line, is provided, the method comprising;

- combining pipeline sections into a pipe stand in the S-lay production line, wherein the pipe stand is to be launched into sea using the J-lay tower;

- transferring the pipe stand from the S-lay production line into the firing line of the J-lay tower, the transferring comprising: - moving the pipe stand in a substantially axial direction out of the S-lay production line and into a substantially horizontal pick-up position on the stinger;

- upending the pipe stand and moving the pipe stand into the firing line of the J-lay tower;

- supporting the pipe stand in the J-lay firing line and combining the pipe stand with a seagoing pipeline supported below the pipe stand in the J-lay firing line;

- launching the seagoing pipeline, including the pipe stand, into the sea by way of the J-lay method.

Thus, with a method according to the claimed invention, the S-lay production line is used for providing the pipe stands to be launched by the J-lay tower. By transferring the pipe stand to the J-lay tower via the stinger, the pipe stand can be manufactured in the S-lay production line and can be moved out of the S-lay production line via the exit that is also used for launching continuous pipeline by way of the S-lay method.

Thus, with a method according to the invention, a single production line can be used for providing pipeline to be launched by way of the S-lay method and for producing pipe stands to be launched by way of the J-lay method. The production does not require major changes in lay out and/or set up with respect to a typical S-lay production line, such as a lateral exit for moving the pipe stands to a deck mounted pick up position. The latter would for example increase the foot print of the production line significantly.

The invention thus provides an alternative an alternative method of installing pipeline from a vessel by way of the J-lay method, and allows for a more efficient design and layout of a vessel comprising both S-lay and J-lay facilities.

In an embodiment, the method further comprises:

- after moving the pipe stand in a substantially axial direction out of the S-lay production line, moving the pipe stand in a substantially lateral direction, for example by lifting or rolling the pipe stand, into the substantially horizontal pick-up position.

In an embodiment, the method further comprises:

- using a pipe stand transfer device to engage the pipe stand located in the pick-up position, and subsequently to upend the pipe stand and to move the pipe stand to the firing line of the J-lay tower, preferably to move the pipe stand into the firing line of the J-lay tower. In an embodiment, the further comprises:

- using a pipe stand transfer device to engage the pipe stand located in the pick-up position, and to transfer the pipe stand into a pipe stand storage near the J-lay tower;

- wherein the pipe stand storage, preferably, is configured to support pipe stands with a vertical orientation, and the pipe stand is upended prior to being located in the pipe stand storage;

- transferring the pipe stand from the pipe stand storage into the firing line of the J-lay tower.

In an embodiment, the stinger is a dedicated S-lay stinger for S-lay use only, and the method further comprises:

- removing the dedicated S-lay stinger and mounting a dedicated pipe stand stinger, for receiving the pipe stand from the S-lay production line and for supporting the pipe stand in the pick-up position.

In an embodiment, the stinger is a dedicated S-lay stinger for S-lay use only, and the method further comprises:

- mounting a pipe stand support structure onto the S-lay stinger to convert the dedicated S- lay stinger into a dedicated pipe stand stinger for receiving the pipe stand from the S-lay production line and for supporting the pipe stand in the pick-up position.

In an embodiment, the stinger is a hybrid stinger, the stinger comprising at least one pivotably mounted stinger section, and wherein the method further comprises moving the pivotably mounted stinger section from an S-lay positon, for supporting pipeline being launched into sea by way of the S-lay method, into a pipe stand support position, for supporting a pipe stand to be launched into sea by way of the J-lay method.

In an embodiment, the stinger is a hybrid track stinger, the stinger having a pipeline support track that comprises multiple movable supported track sections and/or support rollers, and wherein the method further comprises moving the track sections and/or support rollers relative to each other and relative to the stinger frame from a first position in which they define a pipeline support track into a second position in which they define a pipe stand support track.

The invention furthermore provides a method for providing a marine pipelaying vessel according to the invention, preferably, for performing a method according to the invention, the method comprising mounting a pipe stand transfer device or mounting a pipe stand transfer device and a J-lay tower at the stinger end of a vessel comprising an S-lay production line, a stinger and a J-lay tower or on a vessel comprising an S-lay production line and a stinger, respectively.

The invention furthermore provides a J-lay pipelaying method, wherein use is made of a vessel with an S-lay production line, a stinger associated with the S-lay production line, and a J-lay tower defining a J-lay firing line, the method comprising;

- combining pipeline sections into a pipe stand in the S-lay production line, wherein the pipe stand is to be launched into sea using the J-lay tower;

- transferring the pipe stand from the S-lay production line into the firing line of the J-lay tower, the transferring comprising:

- moving the pipe stand in a substantially axial direction out of the S-lay production line and into a substantially horizontal pick-up position on the stinger;

- upending the pipe stand and moving the pipe stand into the firing line of the J-lay tower;

- supporting the pipe stand in the J-lay firing line and, preferably, combining the pipe stand with a seagoing pipeline supported below the pipe stand in the J-lay firing line;

- lowering the pipe stand into the sea by way of the J-lay method.

In an embodiment, the pipe stand transfer device is a crane, for example a mast crane, which crane is configured to engage the pipe stand located in the pickup position in such an embodiment, the crane is, preferably, configured to not only lift the pipe stand out of the pickup position, but also to up end the pipe stand and to present the upended pipe stand at the J-lay firing line of the J-lay tower.

Furthermore, the J-lay tower is configured to receive the upended pipe stand in the J-lay firing line, either directly, by the pipe stand transfer device positioning the pipe stand in the J- lay firing line, or indirectly, by the pipe stand transfer device presenting the pipe stand to a pipe stand loader provided on the J-lay tower, which loader is configured to engage the pipe stand and correctly position the pipe stand in the j-lay firing line. For example, the loading device may comprise multiple pivotably and/or telescopic gripper arms located along the J- lay firing line for engaging, supporting and positioning a pipe stand relative to the J-lay firing line.

In an alternative embodiment, the crane delivers the pipe stand to a pipe stand loader device, which loader device is configured to present the pipe stand at, preferably in the j-lay firing line, and, optionally, to upend a pipe stand delivered by the crane in a horizontal position.

In an embodiment, the crane is provided with double and independent hooks, one for each end of the pipe stand, for lifting and upending the pipe stand.

Advantageous embodiments of the vessel according to the invention and the method according to the invention are disclosed in the subclaims and in the description, in which the invention is further illustrated and elucidated on the basis of a number of exemplary embodiments, of which some are shown in the schematic drawing. In the figures,

components corresponding in terms or construction and/or function are provided with the same last two digits of the reference numbers.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

Fig. 1 shows a top view and a side view of a marine pipelaying vessel according to the invention, with a pipe stand in an s-lay production line;

Fig. 2 shows a top view and a side view of the marine pipelaying vessel of figure 1 with the pipe stand moved onto a stinger;

Fig. 3 shows a top view and a side view of the marine pipelaying vessel of figure 1 with the pipe stand moved into an intermediate transfer position by a pipe stand transfer device;

Fig. 4 shows a top view and a side view of the marine pipelaying vessel of figure 1 with the pipe stand transfer device depicted upending the pipe stand in the side view;

Fig. 5 shows a top view and a side view of the marine pipelaying vessel of figure 1 with the pipe stand being lowered by a J-lay tower;

Fig. 6 shows a top view and a side view of the marine pipelaying vessel of figure 1 with the J- lay tower in a tilted position for receiving a pipeline accessory, for example a PLET;

Fig. 7 shows a top view and a side view of the marine pipelaying vessel of figure 1 with the stinger and the J-lay tower I a transit position; Fig. 8 shows a partial side view of the vessel of figure 1 with an S-lay stinger, which S-lay stinger is depicted in a transit position and in an S-lay position, and with the J-lay tower in a lowered position; and

Figs. 9-11 shows in close up and in top view subsequent steps of the transfer process, more in particular the pipe stand transfer device of the vessel of figure 1 engaging the pipe stand, moving the pipe stand in the intermediate transfer position, and lifting the pipe stand into the J-lay firing line respectively.

DETAILED DESCRIPTION OF THE DRAWINGS

Figure 1 shows an exemplary embodiment of a marine pipelaying vessel 1 for installing an offshore pipeline by way of the S-lay pipelaying method and by way of a J-lay pipelaying method. The vessel comprises a hull 2, the hull having a stinger end 3. In the embodiment shown, the vessel has the stinger end at the stern of the vessel. Personal quarters 4 are provided at the bow of the vessel.

According to the claimed invention, the vessel 1 is provided with a J-lay tower 5, an s-lay production line 6, a stinger 7, and a pipe stand transfer device 8.

In addition, in the exemplary embodiment shown, the vessel 1 is furthermore provided with two track based cranes 16 which are only depicted in the top view, and with a large mast crane 17 that straddles the S-lay production line 6.

The J-lay tower 5 is mounted on the hull 2 of the vessel 1. The J-lay tower 5 defines a J-lay firing line 9 for launching pipeline into the sea by way of the J-lay method.

In the embodiment shown, the j-lay tower is pivotably mounted to the hull of the vessel, such that the angle of the J-lay tower can be adjusted. In the exemplary embodiment shown, the J-lay tower can be lowered into a transit positon, see figure 8.

In the embodiment shown, the S-lay production line 6 is located on the deck of the vessel. In an alternative embodiment, the S-lay production line is located in the hull of the vessel, and an exit opening for guiding pipeline onto the stinger is provided in the side of the hull of the vessel.

The S-lay production line 6 comprises one or more welding stations, not shown, for combining pipeline sections into a pipeline to be launched into sea at the stinger end 3 of the hull 2 using the S-lay method. The S-lay production line furthermore comprises one or more tensioners, not shown, downstream of the one or more welding stations for supporting the weight of the launched pipeline.

The stinger 7 is mounted to the vessel 1 at the stinger end 3 thereof and in line with the S-lay production line 6. The stinger 7 is configured to receive a pipe stand 10 from the S-lay production line 6 and to support the pipe stand in a pickup position.

The stinger 7 comprises a framework that supports a pipeline support track 13 for receiving and supporting a pipe stand 10 form the S-lay production line, and for receiving and guiding pipeline from the s-lay production line to the sea floor.

In the embodiment shown in figure 1 , the stinger 7 is a truncated stinger suitable for supporting the pipe stand 10 to enable pipelaying according to the claimed J-lay method, and not for guiding a pipeline to the sea floor to enable pipelaying according to the S-lay method.

In the embodiment shown in figure 8, the stinger 7 is provided with an additional stinger section 11 , and is thus configured to guide a pipeline launched from the S-lay production line 6 to the sea floor to enable pipelaying according to the S-lay method.

The stinger 7 is pivotably mounted to the hull of the vessel, and is supported by draw works 12. The draw works enable pivoting of the stinger relative to the hull of the vessel, for example between a lifted transition position and a lowered S-lay position, see figure 8.

In the particular embodiment shown, the draw works are supported linked to the base of the mast crane 17. Winches, no shown, for adjusting the length of the draw works are mounted in the base of the mast crane.

When the stinger 7 is used for J-lay, the stinger is preferably truncated by removing the distal stinger section 11. Furthermore, draw works are only provide on a single side of the stinger, to provide the pipe stand transfer device with free access to the pipe stand supported on the stinger. When the stinger is used for S-lay, more extensive draw works are provided, in the embodiment shown on opposite sides of the pipeline guide track.

In the embodiment shown, the stinger 7 is provided with a pipeline support track 13 that comprises multiple movable support rollers 14. The support rollers 14 can be moved relative to each other and relative to the stinger frame 15 between a first position and a second position.

In the first position, the rollers 14 define a pipeline support track, or at least part thereof, for guiding pipeline to the sea floor by way of the S-lay method, as depicted in figure 8.

In the second position, the rollers 14 define a pipe stand support track, as depicted in figure 1.

It is to be noted that, in addition to changing the positon of the rollers 14, the angle of the stinger with respect to the vessel is adjusted, to enable the stinger to support the pipe stand 10 in the pickup position.

The stinger 7 of the exemplary embodiment shown is a hybrid stinger. The stinger can be changed between an S-lay configuration, depicted in figure 8, and a pipe stand support configuration, depicted in figure 1. The change requires pivoting the proximal stinger section, that is the stinger section closest to the hull of the vessel, and removing the distal stinger section.

The hybrid stinger furthermore comprises a hybrid track. The hybrid track stinger comprises a track, in the embodiment shown defined by multiple separate roller sections, each roller section comprising multiple support rollers, for guiding pipeline. The roller sections, and thus the support rollers are moveable supported, such that the track can be changed between an S-lay configuration and a pipe stand support configuration.

In the embodiment shown, the pipe stand transfer device 8 for transferring the pipe stand from the pickup position on the stinger to the J-lay tower is embodied as a pivotable transfer arm.

In the embodiment shown, the pipe stand transfer device 8 is mounted at the stinger end 3 of the vessel 1 , and between the stinger and the J-lay tower. The pipe stand transfer device 10 is pivotably mounted to the hull of the vessel, such that it can be moved, more in particular can be pivoted, between a lowered position, depicted in figure 1 , for engaging a pipe stand in the pickup position, and a raised positon for presenting the pipe stand at the J-lay tower.

In the particular embodiment shown, draw works are provided for lifting and lowering the transfer arm, which draw works originate from the J-lay tower. It is submitted that alternative up-ending devices may also be used, for example upending devices comprising hydraulic cylinders and/or counterweights etc. to up end the transfer arm.

In the preferred embodiment shown, the J-lay tower 5 is pivotably mounted to the hull of the vessel 1 while the transfer arm 8 is pivotably mounted to the base of the J-lay tower. This is also shown in figures 9-11.

Thus, with the embodiment shown, the transfer arm 8 is moveable, more in particular is pivotable, between a lowered first position for engaging the pipe stand supported in the pickup position on the stinger, and an upstanding or raised second position for presenting the pipe stand to the J-lay tower, preferably presenting the pipe stand in the J-lay firing line.

Furthermore, in the embodiment shown, the transfer arm 8 comprises a main boom 18 and multiple grippers 20, more in particular comprises two pivotably mounted gripper arms 19 supporting grippers 20, along the length of the main boom 18. The gripper arms 19 support the grippers 20 at one end for engaging a pipe stand and are at an opposite end pivotably mounted to the main boom 18 of the transfer arm 8 to enable moving the pipe stand held by the grippers relative to the main boom of the transfer arm.

Thus, the pivotable mounted gripper arms allow for moving the pipe stand relative to the longitudinal axis of the transfer arm, and thus allow for adjusting the height positon of the pipe stand relative to the J-lay tower when the transfer arm is in the raised, or upstanding position to present the pipe stand at the J-lay tower.

In an alternative embodiment, the transfer arm may, for example, comprise a telescopic main boom and/or gripper arms that can move along a track up and down the main boom, to enable moving a pipe stand relative to the longitudinal axis of the transfer arm. Thus, when the transfer arm is in the raised position, the pipe stand held by the grippers can be moved upwards and downwards relative to the J-lay tower to thus correctly position in the pipe stand in the firing line or relative to loading grippers provided on the J-lay tower for moving the pipe stand into the firing line of the J-lay tower.

Thus, the transfer arm can be configured to move the pipe stand along the longitudinal axis of the transfer arm between a first position and a second position, for example by

telescopically extending a section of the transfer arm and/or by pivoting gripper arms about a pivot axis perpendicular to the longitudinal axis of the transfer arm, and thus adjust the position of the pipe stand relative to the J-lay tower to enable transfer from the pipe stand to the J-lay tower, for example to loading grippers or tensioner tracks of the J lay tower.

Furthermore, in the embodiment shown, the main boom comprises a pivotable mounted top section, the top section supporting the gripper arms. By pivoting the top section of the main boom, the grippers, and thus the pipe stand supported by the grippers can be pivoted about the longitudinal axis of the main boom.

In an alternative embodiment, the transfer arm may, for example, be provided with a pivotable base to thus pivot the entire boom about its’ longitudinal axis, or with a main boom having a large radius and gripper arms configured to travel along tracks extending about the circumference, allowing the pipe stand to be moved along a curved trajectory without pivoting the main boom about its’ longitudinal axis.

Thus, the transfer arm can be configured to move the pipe stand about the longitudinal axis of the transfer arm between a first position and a second position, preferably by pivoting a section of the transfer arm and/or the grippers about a pivot axis parallel to the longitudinal axis of the arm. In the embodiment shown, this provides a simple and effective way to move the pipe stand from the pickup position into an intermediate transfer position in with the pipe stand is located in a plane comprising the J-lay firing line. From there it requires only pivoting the transfer arm upward to position the pipe stand in, or at least near, the J-lay firing line.

In an alternative embodiment, the pipe stands are not moved from the pickup positon to the intermediate transfer positon along a curved trajectory, by for example pivoting the mina boom about its’ longitudinal axis, but are translated along a substantially straight trajectory. For example, in an embodiment, the transfer arm comprises lateral arms extending at opposite sides and in opposite directions, and grippers configured to move along those lateral arms from one side of the main boom to an opposite side of the main boom.

The marine pipelaying vessel 1 depicted in figure 1 allows for a J-lay pipelaying method according to the invention, the method comprising the following steps:

- combining pipe sections 21 into a pipe stand 10 in the S-lay production line 6, the pipe stand to be launched into sea using the J-lay tower 5;

- transferring the pipe stand 10 from the S-lay production line 6 into the J-lay firing line 9 of the J-lay tower 5, the transferring comprising: - moving the pipe stand 10 in a substantially axial direction out of the S-lay production line 6 and into a substantially horizontal pick-up position on the stinger 7; and

- upending the pipe stand 10 and moving the pipe stand into the J-lay firing line 9 of the J-lay tower 5.

Preferably, the method further comprises the steps, which are not depicted in the figures:

- supporting the pipe stand 10 in the J-lay firing line 9 and combining the pipe stand 10 with a seagoing pipeline supported below the pipe stand in the J-lay firing line; and

- launching the seagoing pipeline, including the pipe stand, into the sea by way of the J-lay method.

Figure 1 depicts the combining of pipe sections 21 into a pipe stand 10 in the S-lay production line 6, the pipe stand to be launched into sea using the J-lay tower 5. In the figure, the pipe stand transfer arm is depicted in a lowered position, ready to pick up a pipe stand presented on the stinger.

Figure 2 depicts the pipe stand 10 supported on the stinger 7 in the pickup positon. The grippers 20 of the pipe stand transfer arm 8 are positioned for engaging the pipe stand.

In the particular embodiment shown, the pipe stand transfer arm is configured to move the pipe stand from the pickup position into an intermediate transfer position, in which

intermediate transfer position the pipe stand is located in a virtual plane comprising the J-lay firing line. Thus, subsequently pivoting the pipe stand transfer arm upwards to upend the pipe stand also brings the pipe stand in the J-lay firing line. This method comprises a limited number of simple movements, and thus allows for a reliable, accurate and efficient transfer of the pipe stand from the pickup positon to the J-lay firing line.

Figure 3 depicts the pipe stand moved into an intermediate transfer position by the pipe stand transfer device, in the particular embodiment shown by pivoting an upper end of the main boom of the pipe section transfer arm about its’ longitudinal axis and by pivoting the gripper arms towards the top end of the main boom.

Figure 4 depicts the pipe stand transfer arm upending the pipe stand. Figure 5 depicts the pipe stand transfer arm returned to its’s initial position for picking up the next pipe stand, while the previous pipe stand is lowered along the J-lay firing line into the sea. Figure 6 shows the J-lay tower in a tilted position for receiving a pipeline accessory, for example a PLET. In the embodiment shown, the PLET, or other device to be integrated in the pipeline, can be located in the J-lay firing line by the mast crane. In addition, or as an alternative, a PLET loader or similar device can be provided for moving a device form the deck of the vessel into the J-lay firing line.

Figure 7 depicts the stinger and the J-lay tower in a transit position.

Figures 9 - 11 are close-ups of 2, 3 and 4 respectively. Figures 9-11 show in close up and in top view subsequent steps of the transfer process, more in particular the pipe stand transfer device of the vessel of figure 1 engaging the pipe stand, moving the pipe stand in the intermediate transfer position, and lifting the pipe stand into the J-lay firing line respectively. Figure 11 depicts the pipe stand transfer arm in two positions, one while being pivoted into an upright position adjacent the J-lay firing line, and one in the upright position. In the embodiment shown in these figures, the pipe stand transfer arm is pivotable mounted on the base of the J-lay tower.

Reference signs

01 marine pipelaying vessel 02 hull of the vessel 03 stinger end hull

04 personal quarters 05 J-lay tower

06 S-lay production line 07 stinger

08 pipe stand transfer device 09 J-lay firing line

10 pipe stand

11 additional stinger section

12 draw works

13 pipeline support track

14 support rollers

15 stinger frame

16 track based cranes

17 mast crane

18 main boom transfer arm

19 gripper arms

20 grippers

21 pipe sections

22 s-lay firing line

23 pipe stand support track