CA1261207A - Manned autonomous underwater vessel - Google Patents

Abstract

A b s t r a c t A manned autonomous underwater vessel (10), with at least one external manipulator (31), is designed as a load carrying vessel and is provided with at least one external rail track (31; 21, 22) where the manipulator (37) or manipulators (37; 26) are mounted so that it or they can travel with respect to the vessel (10). The external rail track or tracks may be in the form of a vertical rail track (31) in the front part of the vessel and/or in the form of one or more horizontal rail tracks (21, 22) along the bottom of the vessel, inside a cargo area (15) below and outside the pressure hull (13) of the vessel.

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Description

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The present inven~ion relates to a manned autonomous underwater vessel, havlng at least one external manipulator being mounted on support means movable along a yenerally horlzontal rail track, which is mounted externally on the pressure hull of the vessel.
The exploitation of oil and gas resources below the ocean has led to a demand for underwater technology suitable for greater and greater depths. As procluction is moved to greater depths, often in rough weather waters, the need for surface independent underwater systems increases. Several underwater installations have been suggested for location on the sea floor and for remote control, in order to be independent of a surface vessel. Such underwater installations are, however, located in a very demanding environment and it is therefore a requirement that they can be malntained, overhauled and repaired when necessary.
For smaller depths divers are used for such work. At laryer depths divers can only be used to a limited extent, if at all, and it has therefore been suggested to develop so-called mini submarinesr manned or unmanned, provided with suitable manipulators for performing work on the underwater installation.
It has also been suggested to design an underwater installation having an integrated control and service central in the form of a diving chamber, to which personnel can gain access via a diving bell. A disadvantage of the known systems is that one is not entirely independent of a surface vessel. Divers and diving chambers require contact with the surface by means of a so-called umbilical, and th~e same is true for unmanned mini submarines.

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' ~26~7 Also a manned mini suhmarine is dependent on a surface baee nearby in form of a suitable vessel because such mini submarines only have limited operating reach ancl time.
Thus, because one is surface dependent, severe requirements are imposed on the equipment to be placed on the sea floor or submerged. If ~he weather conditions are difficult, one may not always count on being able t:o perform the necessary maintenance work etc. at the desired time, and it may also be difficult to perform overhauls, repairs and replacements. If one or more underwater components fail, one must therefore often completely close down the underwater installation, for instance because one has to await a period of more suitable weather conditions on the surface.
In the Canadian patent application Serial No. 494,356 filed on October 31, 1985 an underwater operating system is described which will be entirely surface independent, with ~he advantages this entails. The underwater operating system includes the use of an underwater vessel which is load carryiny, manned and autonomous. A particular object of the present invention is to suggest such an underwater vessel, but the use of such a vessel is of course not limited to the use in connection with the said particular underwater operating system. It may be used wherever there is a demand for such a vessel, with the advantages it entails.
The object of the invention is therefore ~o provide a manned, self-sufficient underwater vessel, having at least one - .~
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An underwater vessel of this general type is known from US-A-3 ~51 224. Thls vessel is on the underside provided with a head equipped with two manipulator arms. The head is movable along a rail ~rack on the underside of the vessel, but this movement only serves to bring the manipulators from stored position to the position of use. It is not intended that the head should be able to move while the manlpulator arms are in use. The vessel is neither intended for carrying externally accessible cargo nor are the manipulators intended for handling or moving such cargo. This known device can there~ore not fulfil the object of the present invention.
The object of the present invention is fulfilled by a manned self-sufficient underwater vessel of the type mentioned by way of introduction, which is characterized in that the vessel is provided with a load carryiny area at the bottom side and externally of the pressure hull, where a rail track is arranged for a lifting yoke for transferring cargo units which can be carried by the vessel in the load carrying area. Since the vessel is autonomous and can carry cargo which it may be able to handle itself, for instance in the form of e~uipment units which are to be installed or dismantled on well installations at quite large depths, the vessel will have a considerably greater applicabillty, flexibility and efficiency than known vessels.
~utonomous underwater vessel is here supposed to mean an 2a , :

'' . ' underwater vessel which ls self-sufficient, i.e., it ls a true undarwater vessel without the need for an umbilical, and it is supposed to have the capability of staying under water continuously for weeks, having a larger crew, Eor instanca 5 - 10 persons. Such an underwater vessel will have the advantage that one will be entirely independent of 2b ,, ~

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-the weather conditions on the surface when performing necessary operations and work on an underwater installation, since the underwater vessel may be operational at any time and quickly may be brought to the place of employment, carrying the necessary load, i.e. equipment units and components for the underwater installation. Said rail track, permitting travelling of the mani-pulator or manipulators, provides a desired, larger work area for the manipulator while the underwater vessel is at rest, and this facilitates carrying out the necessary work. l'he advantages are even greater if it is possible to dock the underwater ~essel as shown and described in the above mentioned Canadian patent application Serial No. 494,350.
Such a manned autonomous underwater vessel will also be able to reduce the long term demands on the equipment in an under-- water installation, without reducing safety, particularly since one at the desired time quickly may gain access for performing the necessary work, replacements etc. The need for complete shut-off of an installation, e.g. a cluster of production threes with corresponding manifold equipment, will also be reduced or possibly be eliminated because one can perform any necessary repairs or replacements, e.g. in a manifold part or in a production three, without the necessity o~ closing down the other sections of the installation.
The underwater vessel can work at very large depths, well outside the reach of divers, and-a particular advantage is that the underwater vessel also may be used in arctic waters (below ice).
The vessel may advantageously have a vertical rail track at the front of the vessel. Such a vertical rail track is particularly advantageous for a manipulator which is to perform work on a tow~r-like structure, e.g. a production tree.
The rail track may advantageously be movably ~ a~
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supported on the vessel, and a particularly advan-tageous form is one wherein the ver-tical rail track is movable horizontally in the longitudinal direction of the vessel. Then the rail track may be moved with respect to the fron-t part of the vessel, and -the rail -track with the appurtenant manipulator may, if needed, be pulled all the way up to the :Eront par-t of the vessel, to a stored position or an inoperative position during transport.
The pressure hull of the vessel may advantage-ously be provided with wall sections which may be opened and which limit a forward space where the manipula-tor is loca-ted when it is in said stored position.
Advantageously, a rail track may be arranged along the bottom or the belly of the vessel, inside a loading area below or outside the pressure hull of the vessel. This rail track may also be designed for a lifting yoke, but preferably a separate rail track is arranged for one (or more) lifting yokes in the loading area, and particularly advantageously the belly manipulator and the lifting yoke and their rail tracks are designed so that the belly manipu-lator and the lifting yoke can pass each other.
In order to facilita-te such passing the belly manipulator may comprise a U-shaped frame running in two rails forming the rail track of the belly manipu-lator, while the lif-ting yoke concurrently comprises a trolley carriage dimensioned for movement in the space between the ~-shaped frame and the vessel, the rail track of the lifting yoke extending inside the rails of the belly manipulator.
In a particularly advantageous embodiment of ~he underwater vessel, supports are arranged in its loading area for equipment units in a upper loading level and in a lower parking level, in which parking level the equipment units will hang out of the way of longitud:inal transport of an equipment unit in . . .

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the loading area by means of the lifting yoke.
Advantageously, the belly manipulator whlch can travel in the loading area, can be retracted to a position within the cross--section oE the loading area and preEerably above the parking level. The belly manipulator may -thus be driven passed -the parked equipment units.
Preferably, -the vessel is designed so -that -the loading area is defined by the pressure hull of the vessel and cargo room walls suspended from the hull.
The walls may be opened, e.g. by being pivotable, or for instance foldable. During transit between the base of the underwater vessel and the place of emplo-ment, the equipment units, the belly manipulator and the lifting yoke may be pro-tected inside a cargo room, simultaneously obtaining a more streamlined ou-ter skin for the underwater vessel during transit.
Preferably the underwater vessel is provided with telescopic or lowerable supporting legs, and these supporting legs may advantageously be provided with supporting wheels which may be intended for cooperation with and locking to a rail track on the or those underwater installations or underwater platforms serviced by the underwater vessel. The underwater vessel may be docked on the supporting legs and may be moved on the rail track to the desired position and locked in this position.
Advantageously, the underwater vessel is pro-vided with windows known per se, preferably large acrylic windows located in the areas where the work is to be performed. Thus, one or more operators in the underwater vessel can obtain direct vision, enabling direct (visual) control and also observation possibilities when conditions are such that televi-sion screen, ~ system con-trol or the like are used.
The underwater vessel may preferably carry a tool storage unit (tool box) in its cargo room. Here the manipulators can fetch tools for working on the : ~ .

~6~ 7 equ:ipment units. The tool box may be desigl1ed like a carrousel supported in a frame, which in turn may be connected to the lifting yoke.
The invention shall be more closely described with reference -to the drawings, where:
Fig. l shows a perspective view of an under-water installation with an underwater vessel accor-ding to the inven-tion, Fig. 2 shows a schematic: side view of a under-wa-ter vessel according to the invention, the rear part of the vessel being deleted, Fig. 3 shows a schema-tic fron-t view on a some-waht larger scale of the underwater vessel in Fig. 2, Fig. 4 shows a schematic partial view of the front part of the underwater vessel during the per-formance of work on a production three, Figs. 5 and 6 show a schematic end view and a schematic plan view of the vessel and the produc-tion three in Fig. 4, and Fig. 7 shows a schematic side view of an under-water vessel with a tool storing unit.
In Fig. l an underwater installation l is schematically shown, here in the form of an under-water production platform having four well areas 2,

3, 4, 5 and appurtenant manifold equipment, represen-ted by the framework 6. Only one production t ~ 7 ~ti ~ is shown. On the manifold 6 a rail track is arranged, generally consisting of two rails 8 and 9, and on this rail track an underwater vessel l0 is shown. The underwa-ter vessel l0, which is shown schematically, is about to approach the underwater - installation for docking on the rails 8, 9 in a man-ner -to be described more closely below in connection with Figs. 2 and 3. Suffice it here -that the under-water vessel l0 in Fig. l has a cargo room ll and a front room 12. Bo-th these rooms are shown in closed condition, i.e. the bow doors are closed and -the same is true for the belly doors limi-ting the cargo room .

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11 outwards.
The underwater vessel ltself will described more closely in the Eollowlng, particularly wi-th re-ference to Figs. 2 and 3.
The underwa-ter vessel 10 has a pressure hull 13. This pressure hull 13 is surrounded by an outer hull 14. On the belly side of -the pressure hull 13 a loading area or cargo room 15 is arranged, where cargo may be placed in a manner no-t shown in further detail, here sugges-ted by dash-do-t lines indicating the contour of modules or equipment units 17. The cargo room 15 is provided with attachment supporting devices ~6 enabling posi-tioning of the equipment units 17 inside the cargo room, as shown to the right in Fig. 2. In -this parked posi-tion the side walls of the cargo room is of course swung outwards, as indi-cated by dash-dot lines in Fig. 3, where side walls 16, 18 are shown swung outwards and folded,respec-tively.
The various equipment uni-ts 17 may be handled in the cargo room by means of a lifting yoke 19, which is supported to be raised and lowered in a trolley carriage 20. This trolley carriage 20 can run in two rails 21, 22 mounted under the belly of the pressure hull 13. These rails 21, 22 extend parallel to each other and to the longitudinal axis of the vessel.
Outside these rails 21, 22 for the trolley car-riage two parallel rails 23, 24 are attached, alsoto the pressure hull, wherein a manipulator frame 25 is movably suspended, the frame being U-shaped in the section in Fig. 3. In this frame 25 a belly manipulator 26 is mounted. From Figs. 2 and 3 it will be apparent that the lifting yoke 19 with the corresponcling trolley carriage 22 can pass by the frame 25, so that the lifting yoke and the belly manipulator can move along the bottom side of the pressure hull without interfering wlth each other.

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The parkiny poss:Lbility for the equipment units 17 permits moving of the equipment units with respect to each other in the cargo room, and also permits moving of an equipment uni-t 17 by means of the lif-ting yoke 19 past -the helly manipulator 25, 26 if the need arises. In its folded condition, the belly manipula-tor 26 is located above the parklng level, as shown in Fig. 2. The folded position is shown in solid lines in Figr 3. Broken lines in Fig. 3 show a possible working position of the belly manipulator 26.
Furthermore, four guides 27, 28, 29, 30, -two on each side of the pressure hull, are provided on the pressure hull 13. In these guides a front verti-cal rail track 31 is supported horizon-tally movable by means of horizontal beams 32, 33 (Fig. 2).
The vertical rail track 31 is in fact designed as a double vertical rail track having two vertical rails 34, 35, and on each of these rails a bow mani-pulator 36, 37 is movably supported ~see also Figs.

4, 5 and 6). In Fig. 3 only one of the bow manipu-lators is indicated and given reference numeral 36, while Fig. 2 shows the other bow manipulator 37, in fact only its rail track part.
In Fig. 2 the vertical rail track 31 is shown extended. Dash-dot lines show a retracted position for the rail track 31 inside a front room 38, which may be closed by means of bow doors not shown.
The underwater vessel 10 is provided with four telescopic legs 39. At the top these telescopic legs are attached to the pressure hull 13, and at the bottom they are each provided with a set of running wheels 40, by means of which the underwater vessel may rest on the rails 8 and 9 indicated in Figs, 2 and 3, see also Fig. 1.
When the underwater vessel is to be docked on the rails 8, 9, one opens the cargo room doors 16, 18 and run the legs out for contact with the rails.

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Thereupon, one may, by means of the telescopic legs 39, adjust the position of the vessel on -the rail track. The underwater vessel may be locked to the rail track by means no-t shown, such as pivotable claws or the like.
The underwater vessel may be provided with equipment known per se and not shown, such as light projectors, TV cameras etc., bu-t primarily the intension is that an operator inside the pressure hull 13 shall have direct visual control over the manipula-tors. In order to make this possible, a large acrylic window 41 is arranged in the nose of the pressure vessel, see also Figs. 4 - 6. Further-more, several large acrylic windows 42 are providedon the belly side (shown by broken lines).
A hydraulic, foldable crane is shown a-t 43.
Furthermore, the submarine also has side thrusters 44.
For driving the trolley carriage 20 any suit-able motor may be used. Likewise, for raising and lowering the lifting yoke 19 a suitable hoist may be arranged in the trolley carriage 20. The lifting yoke 19 may be a magnetic yoke or it may be provided with hooks or other attachment means known per se suitable~for cooperation with the equipment units 17.
Likewise, the frame 25 for the belly manlpulator 26 is provided with a suitable drive means for moving along the rails 23, 24. The manipulators may be electrically or hydraulically driven in a manner known per se. The bow ports and the cargo room ports may be opened and closed by means known per se, e.g.
by means of hydraulic operating cylinders or electri-cally or hydraulically driven spindle mechanisms.
In Figs. 4, 5 and 6 it is shown how the bow manipulators 36, 37 may be used for performing work on a valve ~h~_~5. One sees that the operator inside the ~P~cYre hull 13 has a direct view through the acrylic window 41. The vertical rails 34, 35 may - ` ;: . : '':
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- 10 ~ 22~13-38 be moved horizontally in the longitudinal direction of the vessel, as mentioned above. The manipulators 36, 37 themselves may be moved vertically alony their rails 34, 35. In Figs. 4, 5 and 6 the manipulators 36, 37 are shown in different working positions, and their respective working areas are indicated by the curved dash-dot lines.
Fig. 7 shows how the underwater vessel 10 is provided with a "tool box" 48, which from a position in the cargo room 15 may be "parked" in the front position, the lifting yoke 19 being used for this relocation. The bow manipulator 37, and also the belly manipulator 26 can etch/place tools in this unit 48. The unit 48 may preferably be designed as a carrousel (not shown).
For further details regarding "containerization" of the equipment units and the support of the module or equipment units, reference is made to the concurrent Canadian patent application Serial No. 494,356 mentioned above.

Claims (12)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A manned autonomous underwater vessel, having at least one external manipulator being mounted on support means movable along a generally horizontal rail track, which is mounted externally on a pressure hull of the vessel, characterized in that the vessel is provided with a load carrying area at the bottom side and externally of the pressure hull, where a rail track is arranged for a lifting yoke for transferring cargo units which can be carried by the vessel in the load carrying area.

2. An underwater vessel according to claim 1, characterized by a generally vertical rail track for at least one manipulator at the front part of the vessel, said generally vertical rail track being supported in the vessel for generally horizontal movement.

3. An underwater vessel according to claim 2, characterized in that at the front of the pressure hull of the vessel wall sections are supported, said wall sections, as known per se, being openable and defining a room wherein the manipulators are located when not in use.

4. An underwater vessel according to claim 1, characterized in that a further rail track for a belly manipulator is arranged in the load carrying area.

5. An underwater vessel according to claim 4, characterized in that the belly manipulator and the lifting yoke and their rail tracks are designed so that the manipulator and the lifting yoke may pass each other.

6. An underwater vessel according to claim 5, characterized in that the belly manipulator comprises a U-shaped frame running in the rail track of the belly manipulator, and in that the lifting yoke comprises a trolley carriage dimensioned for travel in the space between the U-shaped frame and the vessel, the rail track of the lifting yoke extending inside the rail track of the belly manipulator.

7. An underwater vessel according to claim 1, characterized in that it comprises supporting means for equipment units at an upper loading level and a lower parking level in the load carrying area, at which parking level the equipment units will hang out of the way of longitudinal transport of an equipment unit in the load carrying area by means of the lifting yoke.

8. An underwater vessel according to claim 7, characterized in that the belly manipulator, movable in the load carrying area, is retractable to a position inside the cross-section of the load carrying area and preferably above the parking level.

9. An underwater vessel according to one of the claims 1 -3, characterized in that the load carrying area is limited by the pressure hull of the vessel and cargo room wall supported from the pressure hull, the walls preferably being pivotable, or foldable.

10. An underwater vessel according to one of the claims 1 -3, characterized in that it comprises telescoping or lowerable supporting legs on the vessel.

11. An underwater vessel according to one of the claims 1 -3, being provided with a tool storage unit where the manipulator can fetch and place tools, characterized in that the tool storage unit is designed as a carrousel.

12. An underwater vessel according to one of the claims 1 -3, characterized in that it comprises a CAD control system for the manipulators.