GB2160156A

GB2160156A - Launching structures for remotely-operated submersible vehicles

Info

Publication number: GB2160156A
Application number: GB08415163A
Authority: GB
Inventors: John Kelvin Pirie
Original assignee: SEAMETRIX Ltd
Current assignee: SEAMETRIX Ltd
Priority date: 1984-06-14
Filing date: 1984-06-14
Publication date: 1985-12-18

Abstract

A launching structure 1 for remotely-operated submersible vehicles which includes a first tether-management system B for paying out and taking in a first umbilical tether 7 connected to a first remotely-operated submersible vehicle 4, a first docking zone 3 for the first vehicle 4 situated directly below the first tether-management system B, a second docking zone 5 directly below the first docking zone 3 for a second remotely-operated submersible vehicle 6 or other payload 32, and a second tether-management system 9 directly below the second docking zone 5 for a second umbilical tether 31 which can be connected to the second vehicle or other payload 32. The first tether-management system B and docking zone 3 may be detachable from the second docking zone 5 and tether-management system 9. <IMAGE>

Description

SPECIFICATION Improvements in and relating to launching structures for remotely-operated submersible vehicles The invention relates to launching structures for the launching and deployment of remotely-operated submersible vehicles underwater.

In this specification, "remotely-operated submersible vehicle" is used to refer to apparatus having means of propulsion underwater and one or more other capabilities operable from a position remote from the vehicle, usually above the surface of the water. Such a vehicle is generally controlled from an operation console on the surface via an umbilical cable or tether connected to the vehicle.

The tether may have to be of considerable length,and the handling or management of the tether has inherent difficulties.

The vehicle is generally launched from the surface, for example, from the deck of a ship, in a launching structure often referred to as a "garage", attached to a lift cable controlled from a handling system on deck.The launching structure has a cage for the vehicle and a drum upon which the umbilical tether is wound, and the vehicle is deployed in that structure to a desired depth underwater and to a chosen site. On deployment, the vehicle can be directed to leave, and return to, the cage as required, and the tether unwound from or wound up upon the drum accordingly in response to control signals transmitted from the operation console on deck via the lift cable to the launching structure and from there via the umbilical tether to the vehicle.

The invention provides a launching structure for remotely-operated submersible vehicles which includes a first tether-management system for paying out and taking in a first umbilical tether connected to a first remotely-operated submersible vehicle, a first docking zone for the first vehicle situated directly below the first tether-management system on deployment of the launching structure underwater, and from or into which the first vehicle can leave and return, a second docking zone directly below the first docking zone from or into which a second remotely-operated submersible vehicle or other payload can leave and return, and a second tether-management system directly below the second docking zone for paying out or taking in a second umbilical tether connected to the second vehicle or other payload.

The launching structure of the invention makes possible the launching of two remotely-operated submersible vehicles, or one such vehicle and another payload from a single launching structure in a single launching operation, and a reduction in the deck space previously needed for transporting launching equipment for two such vehicles, and the time necessary for their launching and deployment. It also makes possible a variety of different operating systems.

Firstly, the launching structure may be used with two remotely-operated submersible vehicles, each connected to an umbilical tether on its own tethermanagement system, each tether-management system being operated and/or controlled from an operation console and each tether transmitting operation and/or control signals from the operation console to its associated vehicle. In use, the two vehicles can leave and return to the launching structure, and be operated, completely independently of each other or in conjunction. They may be similar vehicles, or vehicles capable of performing different functions. One of such vehicles can be used as back-up for the other, and it is possible to double the work capability whilst reducing the deck space previously needed for transporting launching equipment for two such vehicles and the launching and deployment time.

Such an arrangement makes possible the deployment of diverse systems from a single launching structure. For example, one of the vehicles may be a diver observation or general inspection vehicle and the other a larger non-destructive testing vehicle with suitable sensors, water jet equipment, manipulators and/or cleaning equipment.

Alternatively, the launching structure may be used with some other payload having no means of propulsion, for example, an additional equipment package or work package, in the second docking zone.

With this arrangement, advantageously, the first remotely-operated submersible vehicle and/or the payload is provided with coupling means which enables the vehicle to be coupled to the payload in a manner suitable for transporting the payload.

Such coupling means is preferably electro-hydraulic but it may also be mechanical or electromagnetic.

Accordingly, it is possible for the vehicle either initially before it leaves the first docking zone of the launching structure or on return to the zone after, for example, an initial inspection, or after finishing an operation in which the additional equipment was not required, to couple itself to the equipment package situated beneath it, and transport the equipment package out of the second docking zone to a chosen work site. The equipment package may comprise, for example, a diver observation or general inspection unit, equipment necessary for maintenance and/or repair of sub-sea installations such as cleaning equipment or control equipment capable, for example, of valve actuation, or non-destructive testing equipment, but need not be provided with any means of propulsion.

The payload may be connected to a second umbilical tether on the second tether-management system and, once in position, be completely released by the vehicle and operated and/or controlled independently of the vehicle directly from the surface via its own tether.

Alternatively, the payload may be arranged to be operated and/or controlled by the first vehicle (and hence indirectly from the surface) rather than via its own umbilical tether on the second tether-management system. Thus, the vehicle may remain coupled to the payload, the transportation coupling means also providing electrical connection be tween the first vehicle and the payload such as to enable operation and/or control of the payload, or the payload may have its transportation coupling disconnected but remain electrically connected to the vehicle by a secondary umbilical tether controlled by the vehicle, the vehicle then being able to stand- off from the payload. Accordingly, the first vehicle may include a secondary umbilical tether arranged to permit operation and/or control of the payload on connection to it.

Alternatively, the payload may be operable accoustically or by data link either from the first vehicle or directly from the surface or another sub-sea installation, for example, a beacon. With this arrangement, the vehicle is also able physically to release the equipment package and proceed independently.

In addition to a payload of an additional equipment package, the second docking zone can, for example, be used to transport one or more explosive charges, which can be set by the vehicle.

Alternatively, transportation of the equipment package can be provided by a diver, the package comprising equipment required by the diver or for work functions as described above.

In any of the above arrangements, where a second umbilical tether on a second tether-management system is employed, the tethers are advantageously of different buoyancies, the first umbilical tether preferably being positively buoyant and the second umbilical tether being neutrally or very slightly negatively buoyant, so that the two tethers tend to separate from each other in use and the risk of entanglement is reduced.

Advantageously, the launching structure is so arranged that the first tether-management system and the first docking zone is detachable from the second docking zone and the second tether-management system. With this arrangement, the launching structure can provide two separate units each for a single remotely-operated submersible vehicle or other payload which can be launched separately on separate lift cables and operated independently of each other. Preferably, the first and second docking zones are located within a doublesized cage made of a framework of interlocking members which are detachable to form two singlesized cages, each for a single vehicle or other payload. The members, may, for example, be tubular, interlock by nesting within each other and be secured together with bolts.The members are also preferably arranged so that the dimensions of the double-sized cage can be varied to suit different sizes and types of vehicles.

A launching structure for remotely-operated submersible vehicles, and assemblies of such a launching structure, a first remotely-operated submersible vehicle and a second remotely-operated submersible vehicle or other payload constructed in accordance with the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic view, partly in section, through the apparatus of the invention,. and Figures 2 to 7 show diagrammatically different operating systems that can be used with the apparatus of the invention.

Referring to Figure 1 of the accompanying drawings, a launching structure,indicated generally by the reference numeral 1, comprises a double-sized cage, indicated generally by the reference numeral 2, defining a first docking zone 3 for a first remotely-operated submersible vehicle 4 and a second docking zone 5 directly beneath the first docking zone 3 for a second remotely-operated submersible vehicle 6. The first vehicle 4 is operated and/or controlled from an operation console (not shown) via a first umbilical tether 7 (shown partly in broken lines) connected to the vehicle.

The tether 7 is paid out or wound in by a first tether-management system, indicated generally by the reference numberal 8, below which the first docking zone 3 defined by the cage 2 is directly located. A second tether-management system 9 similar to the first tether-management system 8 is provided directly below the second docking zone 5 of the cage 2 for a second umbilical tether (not shown in Figure 1) connected to the second vehicle 6. The second vehicle 6 is operated and/or controlled from the operation console via the second umbilical tether.

The tether-management system 8 comprises an oil-filled drum 10 mounted within a protective cover 11 and fixed relative to it. A level-wind mechanism 12 on a reeling arm 13 which is mounted so as to be rotatable relative to the drum 10 are provided to unwind from the drum, or wind up onto it, the umbilical tether 7. From the ievelwind mechanism 12 the tether 7 is guided along a path 14 by means of an hydraulically-operated bailer wheel 15a which frictionally drives the tether and a series of pulleys 15b, which frictionally drives the tether and a series of pulleys 15b, and passing through a docking bullet 16a is connected to the vehicle 4 through an electrical connector and strain relief assembly 16b.The docking bullet 16a co-operates with a positive hydraulically-operated latching mechanism 17 provided on the tethermanagement system 8 when the tether 7 is in a fully wound-in state as shown in the drawing to secure the first vehicle 4 within the first docking zone during transport, launching and retrieval of the structure 1.

The latching mechanism 17 comprises fingers 18 extending through apertures in a sleeve 19 and operable by hydraulic cylinders 20 either to secure the vehicle 4 within the first docking zone 3 as shown in the drawing, or to a retracted position in which the docking bullet 16, and hence the vehicle 4, is released and free to move out of the cage 2. A bumper ring 21 is provided on the vehicle 4 to reduce the possibility of damage during relative movement between the vehicle 4 and the tethermanagement system 8 i.e. during release or docking of the vehicle.

Two electrical pods 22 and 23 are situated within the protective cover 11 of the tether-management system 8. The pod 22 is arranged to transmit electrical control signals from the operation console to the level-wind mechanism 12 and reeling arm 13 to control the unwinding or winding up of the tether 7, and also to ancillary equipment such as cameras (not shown) associated with the cage 2. The pod 23, which is optional, is provided for additional amplification and control of signals to the vehicle 4 via the tether 7, if required.

The tether-management system 9 is identical to the tether-management system 8 but turned through an angle of 180 , but when the tethermanagement systems 8 and 9 are in combined configuration as shown in Figure 1 (rather than used separately as described hereinafter) the pod in the tether-management system 9 correspondong to the pod 22 of the system 8 acts as slave to the pod 22 and is controlled by it.

The pods 22 and 23 (if provided) of the tethermanagement system 8 are electrically connected to a junction box (not shown), the electrical connection for the pods of the tether-management system 9 passing either through the cage 2 or through a separate conduit (not shown) secured to the cage 2. The junction box is electrically connected to the operation console on board ship via an armoured lift cable 24 by which the launching structure 1 is also raised from and lowered into the water. The cable 24 is connected to a further latching bullet 25 mounted on the top of the launching structure 1 for co-operation with a latching mechanism similar to the latching mechanism 17 for securing the launching structure 1 to a handling system on deck before launching and after retrieval, the handling system being used for raising and lowering it.

The cage 2 is a framework composed of three sets of upper and lower tubular members 26 and 27, respectively, extending between the tethermanagement systems 8 and 9, and situated on three sides of the structure 1, the fourth side providing an opening through which the vehicles 4 and 5 can pass. Alternatively, two or four sets of upper and lower members may be provided depending on the configuration of the vehicles. The upper and lower tubular members 26 and 27 of each set interlock by nesting within each other and are secured together by bolts 28 passing through apertures in coupling sleeves 29. Additional apertures 30 are provided in the sleeves 29 to allow the dimensions of the cage 2 and hence the docking zones 3 and 4 to be altered to accomodate different sizes and types of vehicles.The members 26 and 27 can be detached from each other by removing the bolts 28 to form two identical launching structures each for a single vehicle or other payload which can be operated independently, in which case the electrical pod in the tether-management system 9 corresponding to the pod 22 of the system 8 no longer functions as slave to the pod 22 but independently.

In operation, the launching structure 1 is lowered from the deck of a ship using a winch and handling system by means of the armoured lift cable 24, the docking bullet 25 being released from the latching mechamism of the handling system. The launching structure 1 is lowered to a desired depth underwater at a chosen site. From the operation console on deck either or both of the vehicles 4 and 6 can be directed as required via control signals through tethers 7 and 31, respectively, (see Figure 2) to leave the cage 2 through its open fourth side, the level-wind mechanism 12 and the reeling arm 13 of the tether-management system 8 unwinding the tether 7, and that of the tether-management system 9 unwinding the tether 31 by the required number of turns. The vehicles 4 and 6 can be operated completely independently of each other or in conjunction.The vehicles 4 and 6 may be identical vehicles, one giving back up to the other and doubling the work capability, or the vehicles may be capable of performing different functions and hence make possible the deployment of diverse systems from a single launching structure.

For example, the vehicle 4 may be a diver observation or general inspection vehicle and the vehicle 6 provided with non-destructive testing equipment with suitable sensors, water-jet equipment, manipulators and/or cleaning equipment. This operating system is shown in Figure 2. The tethers 9 and 31 are of different buoyancies, the tether 9 being slightly positively buoyant and the tether 31 being slightly negatively buoyant to reduce the risk of entagnlement.

Figure 3 shows a second operating system in which the vehicle 6 is replaced with a payload 32 of additional equipment having no means of propulsion. The payload 32 is connected to the tether 31 on the tether-management system 9, and transport of the payload 32 out of the structure 1 to a chosen work site is provided by the vehicle 4, the payload and the vehicle having electro- hydraulic coupling means 33 for this purpose. Thus it is possible for the vehicle 4 either initially before it leaves the first docking zone 3 or on return after, for example, an initial inspection, or after finishing an operation in which the additional equipment of the payload 32 was not required, to couple itself to the payload 32 by means of the coupling means 33 and transport the payload 32 out of its docking zone 5 (see Figure 3) to the work site.The payload 32 may, for example, be a diver observation or general inspection unit, equipment necessary for maintenance and/or repair of sub-sea installations such as cleaning equipment or control equipment capable, for example, of valve actuation, or nondestructive testing equipment.

Once transported to its chosen work site 34 (see Figure 4), the payload 32 can be completely released by the vehicle 4 and operated and/ or controlled independently of the vehicle 4 directly from the operation console via its tether 31. The tethers 9 and 31 again have different buoyancies to reduce the risk of entanglement.

Alternatively, it may not be necessary for the payload 32 to be operated via its own tether 31, and the structure 1 can be used without the tether 31 being connected to the payload. In such a system (see Figure 5), the vehicle 4 is again coupled to the payload 32 by coupling means 33 to provide transport to a chosen work site, but operation and/ or control of the payload is performed by the vehicle 4 and hence indirectly from the operation console. This can be achieved via the coupling means 33 which can also serve to transmit operation and/ or control signals from the vehicle 4 to the payload 32. Thus the vehicle 4 remains so coupled to the payload 32 by the coupling 33 while the payload performs its required functions.

In another arrangement, the vehicle 4 is provided with a short secondary umbilical tether 35 controlled by a secondary tether-management system 36 (see Figure 6). The secondary tether 35 is connected to the payload 32 and transmits operation andlor control signals from the vehicle 4 to the payload. With this arrangement the coupling 33 can be released, and the vehicle 4 can then standoff from the payload.

In a further arrangement, the payload 32 may be operable accoustically as shown diagrammatically in Figure 7 either from the vehicle 4 as indicated diagrammatically by sound waves 37 or directly from the surface or another sub-sea location, for example, a beacon, as indicated diagrammatically by sound waves 38. Alternatively, the payload 32 may be operable by data link from the vehicle 4 or from the surface or another sub-sea location. In any of these arrangments, the vehicle 4 is able physically to release the payload 32 and proceed independently.

As an alternative to transportation of the payload 32 by the vehicle 4, the payload, which may comprise equipment required by a diver, can be carried by the diver to the work site.

In any of the above arrangements, the launching structure 1 may be disassembled by withdrawing the bolts 28 from the apertures in the sleeves 29 and separating the tether-managment system 8 and first docking zone 3 from the docking zone 5 and the tether-management 9.

Claims

1. A launching structure for remotely-operated submersible vehicles which includes a first tethermanagement system for paying out and taking in a first umbilical tether connected to a first remotelyoperated submersible vehicle,a first docking zone for the first vehicle situated directly below the first tether-management system on deployment of the launching structure underwater, and from or into which the first vehicle can leave and return, a second docking zone directly below the first docking zone from or into which a second remotely- operated submersible vehicle or other payload can leave and return, and a second tether-management system directly below the second docking zone for paying out or taking in a second umbilical tether connected to the second vehicle or other payload.

2. An assembly of a launching structure as claimed in claim 1, a first umbilical tether on the first tether-management system, a first remotelyoperated submersible vehicle connected to the first umbilical tether and capable of entering or leaving the first dockig zone, a second remotely-operated submersible vehicle capable of entering and leaving the second docking zone and a second umbilical tether on the second tether-management system connected to the second vehicle.

3. An assembly of a launching structure as claimed in claim 1, a first umbilical tether on the first tether-management system, a first remotelyoperated submersible vehicle connected to the first umbilical tether and capable of entering and leaving the first docking zone, and a payload having no means of propulsion in the second docking zone.

4. An assembly as claimed in claim 3, wherein the payload is a package of additional equipment.

5. An assembly as claimed in claim 3, or claim 4, wherein the first remotely-operated submersible vehicle and/or the payload is provided with coupling means which enables the vehicle to be coupled to the payload in a manner suitable for transporting the payload.

6. An assembly as claimed in claim 5, wherein the transportation coupling means is electro-hydraulic.

7. An assembly as claimed in claim 5, wherein the transportation coupling means is mechanical or electro- magnetic.

8. An assembly as claimed in any one of claims 3 to 7, which also includes a second umbilical tether on the second tether-management system connected to the payload.

9. An assembly as claimed in any one of claims 3 to 7, wherein the payload is arranged to be operated and/or controlled by the tirst vehicle.

10. An assembly as claimed in claim 9, wherein the transportation coupling means also provides electrical connection between the first vehicle and the payload such as to enable operation and/or control of the payload.

11. An assembly as claimed in claim 9, wherein the first vehicle comprises a secondary umbilical tether arranged to permit operation and/or control of the payload on connection to it while allowing the transportation coupling means to be disconnected and the vehicle to stand-off from the payload.

12. An assembly as claimed in any one of claims 3 to 7, wherein the payload is operable accoustically either from the first vehicle or directly from the surface or from another sub-sea location.

13. An assembly as claimed in any one of claims 3 to 7, wherein the payload is operable by data link either from the first vehicle or directly from the surface or from another sub-sea location.

14. An assembly as claimed in claim 2, or claim 8, wherein the first and second umbilical tethers are of different buoyancies.

15. An assembly as claimed in claim 14, wherein the first umbilical tether is positively buoyant and the second umbilical tether is neutrally or very slightly negatively buoyant.

16. A launching structure as claimed in claim 1, or an assembly as claimed in any one of claims 2 to 15, wherein the launching structure is so arranged that the first tether-management system and the first docking zone is detachable from the second docking zone and the second tether-management system.

17. A launching structure or an assembly as claimed in claim 16, wherein the first and second docking zones are located within a double-sized cage made of a framework of interlocking members which are detachable to form two single-sized cages, each for a single remotely-operated submersible vehicle or other payload.

18. A launching structure or an assembly as claimed in claim 17, wherein the members are tubular, interlock by nesting within each other and are secured together with bolts.

19. A launching structure or an assembly as claimed in claim 17 or claim 18, wherein the members are arranged so that the dimensions of the double-sized cage can be varied.

20. A launching structure substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.

21. An assembly of a launching structure, first and second umbilical tethers, and first and second remotely- operated submersible vehicles substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.

22. An assembly of a launching structure, a first umbilical tether, a first remotely-operated submersible vehicle and a payload substantially as hereinbefore described with reference to, and as shown in the accompanying drawings.