Boat Stabilization
A technique for stabilizing a boat in open water against a stationary structure is disclosed. The boat has a fender at one end comprising a resilient material, and the boat is urged against the structure to engage the resilient material with the structure. The frictional engagement in combination with the urging force is sufficient to prevent the engaged fender from slipping down the structure. In this way so long as the engagement is sustained, the boat is stabilized against the structure.
This application claims the benefit of United Kingdom Patent Application No. 0512097.7, filed on Jun. 14, 2005, which hereby is incorporated by reference in its entirety.
BACKGROUND OF THE INVENTIONThis invention relates to the stability of boats in open water, and particularly to their stability in active waters when delivering or receiving personnel or goods at a stationary structure. The invention has especial application in relation to offshore structures.
Offshore structures around the world's coasts are becoming commonplace, and particularly with the creation of offshore wind farms, many of these structures are relatively small. Such structures do though, require maintenance and attendance for other reasons, and for these purposes only relatively short visits are often required. Similarly, only short visits are required if all that is involved in the transfer of goods or personnel to or from the stationary structure.
SUMMARY OF THE INVENTIONIn active waters a floating craft is subject to a lot of vertical movement, and this can make difficult the transfer of personnel or goods from the craft to a stationary structure. The present invention seeks to facilitate such transfer by providing a means by which the craft can be temporarily stabilized against the structure. According to the invention such a floating craft has at one end a fender with an exposed surface comprising a resilient material. The craft is urged against the structure to engage the resilient material with the structure such that the frictional engagement in combination with the urging force is sufficient to prevent the engaged fender from slipping downwards relative to the structure. So long as this engagement is sustained, the movement of personnel and goods between the craft and the structure is greatly eased.
With a craft and stationary structure engaged in the manner described above, the active water will of course continue to rise and fall. This will allow the craft to pivot in a vertical plane around the point of engagement, but it is of course important that the water level cannot approach or rise above that point. Accordingly, it is preferred that the frictional engagement between the resilient material and the stationary structure permits slippage of the fender upwards relative to the structure, while resisting downward slippage. By this means the craft preserves a horizontal or upwardly inclined attitude towards the point of engagement.
The resilient material on the fender typically comprises natural or synthetic rubber, and can of course be a combination of different materials. In a preferred embodiment the resilient material comprises a rubber sleeve around a resilient foam core. The resilient material can be secured to the fender by any suitable means, bearing in mind that whatever securement is used has to be water resistant and particularly, resistant to sea water if the system is to be used offshore.
The fender will normally present a flat surface for engagement with the structure, with an area sufficient to make firm engagement with the structure which will typically be a column or pylon projecting from the water. Such a structure will allow the resilient material to engage round a significant area so that good frictional contact can be made. In some embodiments, particularly where the structure with which engagement is to be made is known to comprise a column or pylon, the fender may present a concave surface to increase the contact area. The shape of the surface being offered can of course be matched to a particular structure if regular trips to such structure or structures are to be made. This can be of particular benefit for example, when a craft has to travel to substantially identical turbines in an offshore wind farm. In some circumstances, there could be some merit in the exposed surface on the fender being convex, for engagement for example against and between two stanchions.
The fender itself may be part of the structure of the craft, or part of an assembly for fitting to a craft. Such an assembly might even be transferable between crafts, or a range of assemblies be provided for fitting to the same craft, each assembly being particularly adapted to a form of structure against which the craft is to be stabilized.
BRIEF DESCRIPTION OF THE DRAWINGSThe invention will now be described by way of example, with reference to the accompanying schematic drawings, in which:
The frictional engagement between the bow of the boat and the pylon 4 is maintained by the craft being continuously urged against the pylon. This requires the engine to be kept running, and the stern of the boat where the boat is driven, to remain in the water. It is important then, that the attitude of the boat remains either horizontal as shown, inclined upwardly towards the pylon 4 to sustain the frictional engagement between the bow and the pylon. The frictional engagement with the pylon must resist downward slippage, although upwards slippage can be tolerated. Once the inclined attitude of the boat is established, rising water under the bow and the buoyancy of the bow will lift it relative to the pylon in any event, but with the drive from the engine the engagement will be sustained at a higher, and not a lower level. The weight distribution in the boat may be arranged to ensure that the inclination cannot reach an angle at which the boat itself is at risk.
Claims
1. A method of stabilizing a floating craft against a stationary structure in which the craft has at one end a beam with an exposed surface comprising a resilient material, in which method the craft is used against the structure to engage the resilient material therewith, the frictional engagement in combination with the urging force being sufficient to prevent the engaged beam from shipping downwards relative to the structure.
2. A method according to claim 1 wherein the frictional engagement permits slippage of the beam upwards relative to the structure.
3. A method according to claim 2 wherein the exposed surface of the beam is adapted to facilitate said upward slippage.
4. A method according to claim 1 wherein the resilient material comprises rubber.
5. A method according to claim 4 wherein the resilient material comprises a rubber sleeve around a resilient foam core.
6. A method according to any claim 1 wherein the beam is part of the craft.
7. A method according to claim 1 wherein the beam is part of an assembly fitted to the craft.
8. A method according to claim 1 wherein the craft has a bow and a stem, with a motor for propelling the craft from the stem, and wherein the beam is as the bow.
9. A method according to claim 8 wherein the craft is a monohull boat.
10. A method according to claim 8 wherein the craft is a multihull boat.
11. A water going craft fitted with a beam having an exposed surface comprising a resilient material at an end thereof for engagement with a stationary structure, the exposed surface being adapted upon said engagement with sufficient pressure, to prevent downward slippage of the beam relative to the structure.
12. A water going craft according to claim 11 equipped with a motor with a drive mechanism at the other end of the craft for generating said pressure.
13. A water going craft according to claim 12 wherein the drive mechanism comprises an impeller.
14. A water going craft according to claim 111 wherein the resilient material comprises rubber.
15. A water going craft according to claim 14 wherein the resilient material comprises a rubber sleeve around a resilient foam.
16. A water going craft according to claim 11 wherein the beam is part of an assembly fitted to the craft.
17. A monohull water going craft according to claim 11.
18. A multihull water going craft according to claim 11.
19. An assembly for fitting to a water going craft comprising a beam having an exposed surface comprising a resilient material at an end thereof for engagement with a stationary structure, the exposed surface being adapted upon said engagement with sufficient pressure, to prevent downward slippage of the beam relative to the structure.
20. An assembly according to claim 19 wherein the resilient material comprises rubber.
21. An assembly according to claim 20 wherein the resilient material comprises a rubber sleeve around a resilient foam core.
Type: Application
Filed: Jun 13, 2006
Publication Date: Jan 4, 2007
Inventors: Neil Clarkson (Lancashire), Robbert van Rijk (Aalsmeerderbrug)
Application Number: 11/451,759
International Classification: B63B 59/02 (20060101);