Floating spiral wound pipes are known from the application WO2009/040098. The pipelines are welded together and wound in a spiral in an accessible, safe location near a coast, then they are towed to the spot where the pipeline must be laid.

The advantage is that at the laying location there is almost no need to undertake time-consuming welding. A diameter of the spiral wound pipe is thereby chosen so large that the pipeline is only elastically deformed and thus can easily be straightened again.

This means that the diameter of the spiral wound pipe is typically about 500 times the diameter of the pipeline diameter .

The vessel is designed according to the invention

preferably to handle without further support such a large spiral wound pipe and has the characteristic that a hull of the vessel is at least substantially disc form constructed.

The vessel can, from a central position, move and also rotate the spiral wound pipe, so that it even can offer support with the winding and unwinding of the spiral wound pipe.

A favourable realization of the vessel according to the invention has the characteristic that the vessel is fitted with winches which are attached to cables that extend in radial direction from the vessel.

These cables, can act as spokes in a wheel, attached to the vessel on one side and to the spiral-shaped wound pipeline on the other ^' side. This way the vessel can control the spiral wound pipe and easily move and rotate the pipeline system.

A further very advantageous realization has the feature that a vessel has a propulsion system which includes a directional propulsion mechanisms, so that any required translation and rotation of the vessel is possible.

A further favourable realization is characterized, that the propulsion system includes at least two engines, each coupled with a directional propulsion mechanisms with positioning capabilities, such as a pump associated with a directional nozzle.

The advantage is that the vessel remains usable when an unexpected failure of an engine occurs .

A further favourable realization is characterized that a superstructure of the vessel is watertight constructed and / or the superstructure is retractable mounted in the vessel and the vessel is equipped with a control unit and ballast tanks.

After the winding of a spiral wound pipe is ready, the vessel can be lowered to a depth of several meters and the vessel can be removed from the inside of the spiral wound pipe with a cable tow.

Similarly the vessel can be dragged from outside of the spiral wound pipe to the inside of the spiral wound pipe.

The invention also relates to a system of vessels for moving and rotating a floating spiral wound pipe.

Such a system of vessels, can handle larger spiral wound pipe and can also be used in rough seas. The inventive system is characterized, that a vessel as defined in the preceding sections includes at least one additional vessel in a condition to be attached directly to the floating spiral wound pipe.

Typically such systems will include three additional vessels attached to the inside of the spiral wound pipe and their movements will support the central main vessel. A favourable realization of the inventive system has the characteristic that at least one additional vessel is propelled by directional propulsion mechanisms with

positioning capabilities and allows the additional vessel, once attached to the spiral wound pipe, to contribute to supporting the movements of the central vessel in any direction .

A further favourable realization of the inventive system has the feature that the propulsion system includes a engine, coupled with a directional propulsion system such as a pump associated with a directional nozzle and with positioning capabilities,

A further favourable realization of the inventive system has the characteristic that the additional vessel is equipped at least on one side, with a bracket or half pipe, in a state to use that the diameter of the pipe can be pushed and locked inside the bracket or half pipe to assure a good contact between the additional vehicle and the spiral-shaped pipeline or its protection and/or floater.

A further favourable realization of the inventive system has the feature that the system includes wireless

connection means, arranged to control at least one

additional vessel from the main central vessel or to allow the control for the central vessel and at least one

additional vessel from a control unit located away from the pipeline spiral and its vessels.

The vessel and / or at least an additional vessel can be used unmanned if desired.

The invention also relates to an additional vessel, as part of a system as described in the preceding paragraphs.

The invention will now be further illustrated by the following figures, where:

Fig. 1 shows schematically in top view a spiral

wound up pipeline, together with a vessel according to the invention;

Fig. 2 shows schematically in perspective a possible realization of a vessel under the invention;

Fig. 3 shows schematically in cross-section the engine deck of this vessel;

Fig. 4 shows schematically in top view a spiral wound up pipeline, together with a vessel and three additional vessels under the invention;

Fig. 5A shows schematically in cross-section a possible realization of a machine deck on one of the additional vessels ;

Fig. 5B shows schematically the additional vessel in rear view.

Fig. 1 shows schematically in top view a spiral wound pipe 1, with a vessel 2 according to the invention. Spiral wound pipe 1 is for example welded together on a nearby coast and wound with the use vessel 2 and then with vessel 2 towed to the area where the pipeline should be placed. Spiral wound pipe 1 has a diameter of e.g. 500 meter, so the in the figure shown pipeline has a length of about 12

kilometres . Vessel 2 is for the sake of clarity not shown in the corresponding scale. To tow spiral wound pipe 1 the towing vessel 2 is equipped with cables 3a, .. , 3f with lashing straps, 4a,.., 4f which are attached in an obvious way to the spiral wound pipe 1.

Fig. 2 shows schematically in perspective a possible realization of a vessel 2 according to the invention comprising a disc-shaped body 5 in which an engine room and a crew accommodation is located.

The engine room is equipped with four pumps which can emit water through four jet pipes 6a, 6b, 6c, 6d.

Jet pipes 6a, 6b, 6c, 6d are fitted in four cuffs 7a, 7b, 7c, 7d in such a way that they can independently swivel around, so that vessel 2 can move in any direction and can also rotate around the central axis of vessel 2. This is important for winding and unwinding of pipeline 1.

The engine room is equipped with six winches, from which steel cables 3a, .. , 3f which can be tensioned or released during the voyage and during the rotation of spiral wound pipe 1.

There is a visible cockpit 8 that can be lowered, after which vessel 2 can be lowered below the water surface to pull vessel 2 underneath the spiral wound pipeline 1 and then subsequently pulled outside the spiral wound pipeline 1. To obtain this the cables 3a, .. , 3f first have to be pulled back, and hawse holes 9a, .. , 9f have to be closed in advance by plugs which are pushed from the outside in the hawse holes.

Fig. 3 shows schematically in cross-section the machine deck of vessel 2, on which four diesel engines 10a, 10b, 10c, lOd are placed and four pumps 11a, lib, 11c, lid associated with jet pipes 6a, 6b, 6c, 6d, and ballast 12a, 12b, 12c, 12d with pumps 13a, 13b, 13c, 13d, coupled to a control unit 14 can be used to sink vessel 2 to a

predetermined depth and let it rise again to the surface so vessel 2 can pass the spiral wound pipe 1. Also on the machine deck six winches 15a, .. , 15f are placed, on which cables and lashing straps 4a, .., 4f are connected. Fig. 4 shows schematically in top view a spiral wound pipe 1, with a vessel 2 and three additional vessels 16a, 16b, 16c according to the invention.

Additional vessels 16a, 16b, 16c are fixed to the inside of spirally wound pipe 1 using lashing straps 17a, 17b, 17c, the additional vessels 16a, 16b, 16c are each provided with a propulsion system and they are operated from vessel 2, so that they contribute to the movement or rotation of the spiral wound pipe 1. Straps 17a, 17b, 17c are fixed to every single layer of the spiral and therefore are actually bundles of straps.

Fig. 5A shows schematically in cross section a possible realization of a machine deck of an additional vessel 16, on which a diesel engine 18 is placed that drives a pump 19 which is coupled with a jet pipe 20, all according the in Fig. 2 described propulsion system.

Also four winches are 21a, .. , 21d placed on the machine deck, of which the wires can be attached to pipe 1.

Furthermore, additional vessel 16 is equipped with two brackets 22a, 22b, of which one is in a position to use as a stable connection between the additional vessel 16 and the pipeline 1.

The control of pump 19 and the jet pipes 20 is handled from vessel 2, so vessel 2 and the associated additional vessels can be seen as operating as one entity.

Fig. 5B schematically shows the additional vessel 16 in back view, with pump 19, nozzle -20, winches 21a, .., 21d and brackets 22a, which clamps around the inner winding of pipe 1. It is also possible to control the vessel 2 and additional vessels 16 from a further away control unit like a boat or helicopter .