| JP2004161184 | CABLE LAYING PONTOON |
| WO/1991/015696 | PROCESS FOR LAYING FLEXIBLE TUBULAR CONDUITS USING A PLURALITY OF SHIPS |
| JP03028094 | UNDERWATER CABLE LAYING SHIP |
ANTONSEN, Ottar (Storgata 29, Brattvåg, N-6270, NO)
| CLAIMS 1. A system for storage, deployment and retrieval of at least one elongated flexible member such as a mooring line, a anchor line, a cable and the like aboard a vessel having a main deck, the system comprising: a. A horizontally rotatable carousel adapted to be arranged in a lower deck area below the main deck of the vessel, said carousel is arranged to receive, store and deploy the elongated flexible members, b. Motorized drive mechanism for rotating the carousel, c. Bearing means arranged between the carousel and a lower deck of the vessel, d. A guide chute for leading the elongated flexible member from the outside environment to the lower deck area. The system according to claim 1, wherein the carousel comprises removable dividers. 3. The system according to claim 1 or 2, wherein the carousel is adapted to be retrofitted in an existing vessel having a hatch leading to the below deck area, wherein the carousel is a modular construction, the components of which are to be transferred through the hatch. 4. The system according to one of the proceeding claims, wherein the guide chute leads the elongated flexible member to and from the carousel 5. The system according to one of the proceeding claims, wherein the guide chute is movable. 6. The system according to one of the proceeding claims, wherein the guide chute is arranged with rollers to turn sheaves. 7. The system according to one of the proceeding claims, wherein the guide chute is arranged with a transition funnel through the deck, said transition funnel having a closeable hatch. 8. The system according to one of the proceeding claims, wherein the elongated flexible member comprises synthetic rope. 9. The system according to claim 1 , wherein the carousel has a capacity of up to 28,600 m of 203mm diameter polyester rope. |
The invention relates to a system for storage, deployment and retrieval of at least one elongated flexible member such as a mooring line, a anchor line, a cable and the like aboard a vessel having a main deck. The system is arranged for handling both conventional and synthetic ropes and lines.
BACKGROUND
Many marine applications, such as for example offshore oil platforms and other petroleum-related activities require very long lengths of anchoring chains or cables. Specially designed vessels are utilized to transport and handle these large amounts of chain /cable.
Increasingly, synthetic rope mooring lines are being utilized for offshore
installations. Such synthetic lines are often used in place of traditional chain mooring lines in deeper offshore locations. Synthetic rope is more buoyant, and is almost neutral with respect to weight in the sea, but has a considerable dry weight and volume (typically in permanent moorings ~ 25 kg / m).
Synthetic rope is also used increasingly for anchoring in areas with a large amounts of infrastructure and equipment installed on the seabed. Synthetic rope, together with underwater buoys, can more safely cross over pipelines, cables and other installations on the seabed with less risk of damage to the seabed installations and equipment.
Synthetic rope requires greater care in handling, and presents unique challenges compared to traditional mooring lines however. Synthetic rope is susceptible to damage by contact with steel wire, sharp edges and the like. Synthetic rope also requires significantly more volumetric capacity as the diameter is significantly larger than, for example steel wire or chain moorings.
Storage of synthetic ropes on board anchor handling ships is currently performed using conventional drums located on the main deck of the ship and the deck above the main deck. Since synthetic rope requires much greater storage volume, the current solution is to simply equip the vessel with additional drums. Often vessels are equipped with additional drums under or over the main deck to increase the total capacity.
The current method of handling and storage of synthetic ropes aboard anchoring vessels has the following problems associated with them:
· Since each drum has its own line, with a different entrance path for its line, there will be many different lines crossing in different directions. This increases the risk of damage to the line, as well as presenting a security risk for the crew. • Use of several drums and associated line guidance is a not cost efficient.
• Using several drums positioned at various locations on the ship increases the complexity with respect to maintaining the vessel's stability as the weight of the various drums changes during deployment or retrieval of the line.
· The drums take up valuable space on the main and upper deck that could be better used for other purposes.
SUMMARY OF THE INVENTION
The present invention solves the aforementioned problems with know systems and methods for handling synthetic mooring lines aboard anchoring vessels.
The invention comprises a system for storage, deployment and retrieval of at least one elongated flexible member such as a mooring line, a anchor line, a cable and the like aboard a vessel having a main deck The system comprises a horizontally rotatable carousel adapted to be arranged in a lower deck area below the main deck of the vessel. The carousel is arranged to receive, store and deploy the elongated flexible members. The system further comprises motorized drive mechanism for rotating the carousel and bearing means arranged between the carousel and a lower deck of the vessel. Further a guide chute is included in the system for leading the elongated flexible member from the outside environment to the lower deck area.
The elongated flexible member may comprise synthetic rope.
The carousel may comprise removable dividers such as for selectively altering the storage capacity of the carousel. The carousel may be adapted to be retrofitted in an existing vessel having a hatch leading to the below deck area, wherein the carousel is a modular construction, the components of which are to be transferred through the hatch. The size of the components should be adapted to fit through the hatch. The guide chute may be arranged so as to lead the elongated flexible member to and from the carousel. In one aspect the guide chute is movable. Further, the guide chute may be arranged with rollers to turn sheaves.
The guide chute may be arranged with a transition funnel through the deck, said transition funnel having a closeable hatch.
The carousel may be arranged with a capacity of up to 28,600 m of 203mm diameter polyester rope. In one embodiment of the invention the system comprises a large capacity, rotating horizontal carousel for deployment and storage of synthetic rope located below the main deck of an anchor handling vessel or other vessel. The system may further comprise a transfer system comprising rollers and sheaves for transferring the lines to the deployment winches. According to one aspect, the system is mounted on a dedicated anchor handling vessel, but can also be adapted to mount on other vessels such as barges, cargo vessels, etc.
The carousel may be located on the tank top below the main deck. Rotation of the device may be carried out by one or more drive units located around its periphery, or by other appropriate motorized means. As mentioned above the carousel may have removable structures for dividing the carousel into sections. Deployment and recovery of synthetic rope in the device may be carried out using a support arm equipped with rollers and wheels to prevent contact with sharp obj ects.
The use of a rotating horizontal carousel achieves a significant increase of the vessel's storage volumes in a cost effective manner that does not impair the ship's stability. The vessel optionally has winches for handling traditional mooring lines in addition to the carousel for handling the synthetic lines.
An example of an embodiment of the invention is in the following described with reference to the figs wherein;
Fig 1 shows a partial side cross-section of an anchor handling vessel
Fig 2 shows a carousel according to the invention arranged on the lower deck/tank top under the main deck Figure 1 shows an anchor handling vessel 10 with a main deck 1 1, on which is mounted a conventional winch 12 for handling traditional anchoring lines.
Under the conventional winch is located one or more chain lockers 13 for storage of traditional chain mooring lines and the like. A rotating horizontal carousel 14 for storage and handling of synthetic rope is arranged below the main deck in a lower deck area, more specifically on a lower deck 20 (the tank top). Alternative locations for the carousel can of course be employed, but this area of the ship will normally be preferred due to, for example, issues of stability and space considerations.
Carousel 14 is comprised of segments with sufficient internal structure to carry expected load. Segments are inserted into the vessel through a hatch in the deck and joined together inside the vessel. The number of segments will depend on the size of the hatch and available space inside the vessel. The carousel is fitted with a bearing means arranged on the lower deck 20. The bearing means may comprise rotating wheels and wheel pairs 15 transferring the horizontal and vertical forces to the ship's structure via the lower deck 20.
The capacity and sectioning of carousel 14 may be altered by using removable poles dividers 16. In one embodiment, poles are fitted into slots in the bottom structure to allow dividers to be installed in the carousel. Poles enabling circular sectioning will be linked together at the top.
The center area 17 of the carousel can be used for different purposes, for example as a space for fuel storage and other purposes. The carousel is rotated by motorized drive means, for example by drive units 18, here shown as four friction wheels that rest against the side walls of the carousel. Other appropriate drive means may also be employed, such as a gear and sprocket drive, a belt drive or the like. To lead the synthetic rope to and from the carousel, a moveable chute 19 is employed. According to one embodiment, the guide chute will be arranged with rollers to turn sheaves and a transition funnel through the decks. The transition funnel may be closed by a hatch when not in use avoiding humidity entering into the vessel.
EXAMPLE
An example of a possible arrangement of the system of the invention aboard a vessel for handling synthetic rope is described below, in comparison to a typical traditional anchor handling vessel. One skilled in the art will appreciate that various modifications may be made with the scope of the invention.
Prior art systems
A typical anchor handling vessel of the type with largest present day capacity (these have generally been built within the last five years):
The ship's length: 85 - 1 10 meters
The ship's breadth : 22 - 27 meters Typical winch set-up for handling and installation of mooring systems:
• Main winch
o Special Handling drum Core diameter 3500mm x drum length 5400mm x outer dia. 6500mm o Tow / Working drum
Core diameter 1500mm x drum length 3750mm x outer dia. 2150mm o Tow / Working drum
Core diameter 1500mm x drum length 3750mm x outer dia. 3500mm
Total drum capacity of 3100 meters dia 203mm Polyester rope
• Secondary winch
o 2 x Secondary winch drums
Core diameter 1500mm x drum length 4500mm x outer dia. 4500mm
Drum capacity 2 x 1600 meters (dia 203mm) Polyester rope
• Storage Winches
o 2 x storage winch drums
Core diameter 1500mm x drum length 4500mm x outer dia. 4500mm
Drum capacity 2 x 1600 meters (dia 203mm) Polyester rope
Total capacity of known systems: 9 500 m (dia 203mm) Polyester rope
Example of a vessel equipped with the system according to the present invention The ship's length: 85 - 90 meters
The ship's breadth: 20 - 25 meters Typical winch set-up for handling and installation of mooring systems:
• Main winch
o Anchor Handling Drum
Core diameter 2400mm x drum length 7000mm x outer dia. 5050mm o Anchor Handling Drum
Core diameter 2400mm x drum length 7000mm x outer dia. 5050mm
Total drum capacity of 5400 meters dia 203mm Polyester rope
• Secondary
o 2 x Secondary winch drums
Core diameter 1500mm x drum length 5200mm x outer dia. 4900mm Drum capacity 2 x 2400 meters dia 203mm Polyester rope
• Horizontal, below-deck carousel
o Anchor Handling carousel
Core diameter 6150mm x drum height 5000mm x outer dia. 17800mm Carousel capacity 28,600 m (dia 203mm) Polyester rope
Total capacity: 38 800 m dia 203mm Polyester rope
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