DK202270471A1

DK202270471A1 - A fish farming plant and methods of operation

Info

Publication number: DK202270471A1
Application number: DKPA202270471A
Authority: DK
Inventors: Kjellså Jakobsen Kristoffer; Møgedal Knut; Askeland Roar; Andziulis Nerijus
Original assignee: Aker Solutions As; Aqua Knowledge As
Priority date: 2020-03-19
Filing date: 2022-09-29
Publication date: 2022-10-12
Also published as: WO2021187991A1; GB2608537A; NO346205B1; NO20200328A1; GB2608537B; GB202213809D0

Abstract

A fish farming plant (10; 10’) comprising a first net cage (17) suspended from a buoyant structure (11, 12, 13); a foundation element (16) suspended from the buoyant structure (11, 12, 13) by a suspending element (15); a plurality of tether elements (19) connected at a first end to the first net cage (17) and at a second end to respective link elements (32; 42; 52), each said link element (32; 42; 52) being connected to a respective elongate manipulation element (18); a plurality of connector devices (20; 30; 40; 50) arranged on the foundation element (16); each connector device (20; 30; 40; 50) comprising a releasable locking device (33; 43; 53) configured for selective releasable connection with a portion of the link element (32; 42; 52), and a manipulation element (35; 45; 55) connected to and configured for operating the locking device (33; 43; 53).

Description

DK 2022 70471 A1 1 A fish farming plant and methods of operation Technical field of the invention The invention concerns the field of fish farming.

More specifically, the invention concerns a fish farming plant comprising a first net cage suspended from a buoyant structure and a foundation element suspended from the buoyant structure by a suspending element, as set out by the preamble of claim 1. The invention also concerns methods of removing and installing a first net cage in a fish farming plant.

Background of the invention

Fish farming plants designed for floating in water typically comprise one or more pontoons (buoyant, floating elements, often circular) and one or more net cages (net pens) suspended by the pontoons.

A net cage may comprise a cylindrical main portion and a conical bottom portion; with a foundation element being arranged at the transition between the two portions.

The foundation element may typically be ring-shaped.

A fish farming plant normally has one net cage.

However, some plants have two or more such net cages, one nested inside the other.

For a typical double net installation, the first net cage is an inner net cage intended for keeping the farmed fish or other marine organisms, while second net cage is the outer net cage providing protection against predators and floating objects and serving as a secondary barrier should the first net cage fail.

Weights in the form of lumped weights or a continuous weight such as a foundation element is instrumental in maintaining the shape of the net cages, and therefore has negative buoyancy and in some cases a certain stiffness in order to withstand loads imposed by the body of water and marine life, inside and outside the net cages.

For a double net installation, a rigid foundation element is often required to prevent contact between the nets.

The nets require frequent cleaning and maintenance and sometimes replacement.

The inner net requires handling for fish handling operation such as crowding for slaughtering and treatment (e,g, de-lousing) or for treatment inside the cage.

All nets require frequent cleaning and maintenance, and sometimes replacement.

The process of releasing a net cage, remove and re-install it, is cumbersome and time-

DK 2022 70471 A1 2 consuming.

Typically, this operation can be performed by retrieving both nets or by using ropes and sheaves on the foundation element and routing a tensioned rope to a pontoon above the water line.

The sheaves are exposed to considerable lateral forces.

It is therefore a need for a device whereby this process may be improved.

The same challenge is applicable for single net installations, e.g. when the foundation element has considerable weight there is a risk of damaging the net in case of skew loads etc.

In such case it is a significant benefit in handling the net without lifting the foundation element.

Summary of the invention The invention is set forth and characterized in the main claim, while the dependent claims describe other characteristics of the invention.

It is thus provided a fish farming plant comprising a first net cage suspended from a buoyant structure - a foundation element suspended from the buoyant structure by a suspending element: - a plurality of tether elements connected at a first end to the first net cage and at a second end to respective link elements, each said link element being connected to a respective elongate manipulation element; - a plurality of connector devices arranged on the foundation element; - each connector device comprising a releasable locking device configured for selective releasable connection with a portion of the link element, and a manipulation element connected to and configured for operating the locking device.

In one embodiment, the connector devices and the foundation element are arranged between the first net cage and the suspending element, and the manipulation element comprises a tool interface portion arranged on an opposite side of the suspending element from its respective connector device, whereby the locking device may be operated by a diver or an ROV located outside the suspending element.

Said suspending element may be a second net cage, and the first net cage is nested within the second net cage.

Said suspending element may also be a suspension system for the foundation consisting of ropes, wires, chains etc. connected to the buoyant structure.

The foundation may be a ring element with negative buoyancy.

In another embodiment, the elongate manipulation element is a cable, and in yet another embodiment, the elongate

DK 2022 70471 A1 3 manipulation element is connected to the buoyant structure and configured for manipulation from the buoyant structure.

It is also provided a method of raising a first net cage in a fish farming plant, comprising, - operating the plurality of manipulation elements to release the corresponding link elements from their respective connector device; and - raising the first net cage to a desired location in or above the water while controllably paying out on the respective elongate manipulation element.

It is also provided a method of installing a first net cage in a fish farming plant,

characterized by, - applying tension to the plurality of elongate manipulation elements while lowering the first net cage into the body of water until the corresponding link element is pulled into locking engagement in its respective connector device.

The manipulation elements may be operated to secure the corresponding link elements in their respective connector device.

In both methods, the manipulation elements may be operated by one or more divers or ROVs located outside the second (outer) net cage.

The invented connector device and net cage system make it possible to connect and release a first net cage from a position outside of a suspending element such as a second outer net cage, for example by means of a diver or an ROV.

A plurality of the invented connector devices are arranged on the foundation element.

In one embodiment, the connector device comprises a self-locking mechanism, in that a link element snaps into locking engagement with a locking device when the link element is being pulled into the connector device by manipulation line, for example from a location above the body of water.

The link element may be released by a diver or ROV operating from outside the outer net cage, because the tool interface portion on the manipulation element is located outside the suspending element.

Brief description of the drawings

DK 2022 70471 A1 4 These and other characteristics of the invention will become clear from the following description of embodiments of the invention, given as non-restrictive examples, with reference to the attached schematic drawings, wherein: Figure 1 is a perspective view of floating fish farming plant comprising a first net cage and incorporating a plurality of the invented connector device; Figure 2 is a perspective view of floating fish farming plant comprising a first and a second net cage and being suitable for the invented connector device; Figure 3 is a perspective view of an embodiment of the invented connector device installed on fish farming plant and providing a connection between a first, inner net cage and a second, outer net cage; Figure 4 is a sketch which corresponds to figure 3, and illustrates an alternative connection between the net cages; Figure 5 is a sketch which in a side view illustrates a first embodiment of the invented connector device installed in a fish farming plant and providing a releasable connection between a first, inner net cage and a second, outer net cage, in a locked state; Figure 6 corresponds to figure 5, and illustrates the invented connector device in an unlocked state; Figures 7 and 8 are perspective views which illustrate a second embodiment of the invented connector device, in a locked state; Figure 9 corresponds to figures 7 and 8, and illustrates the invented connector device in an unlocked state; Figure 10 is a perspective view of a third embodiment of the invented connector device installed on fish farming plant; Figure 11 is a sectional view of the connector device illustrated in figure 10, in a locked state;

DK 2022 70471 A1 Figures 12, 13, and 14 are perspective views of a manipulator element, a locking device, and a link element, all of which are part of the third embodiment of the invented connector device; Figures 15 and 16 correspond to figure 11, and illustrate the invented connector 5 device, in an unlocked state and a locked state, respectively; Figure 17 corresponds to figure 11, and illustrates the invented connector device, in an unlocked state and during an initial stage of a docking process; and Figure 18 corresponds to figure 17, and illustrates the invented connector device, in an unlocked state and during a further progressed stage of a docking process.

Detailed description of embodiments of the invention The following description may use terms such as “horizontal”, “vertical”, “lateral”, “back and forth”, “up and down”, “upper”, “lower”, “inner”, “outer”, “forward”, “rear”, etc. These terms generally refer to the views and orientations as shown in the drawings and that are associated with a normal use of the invention. The terms are used for the reader’s convenience only and shall not be limiting.

A connector device 20 may be installed and used on a floating fish farming plant 10, 10° as illustrated in figures 1 and 2. Here, the fish farming plant 10, 10” comprises upper and lower buoyant pontoons 11, 12, interconnected by columns 13. The plant 10,10’ is floating in a body of water W and is moored to the seabed (not shown) by lines or chains 14. The plant 10,10’ comprises a ballast system (not shown), whereby the plant may be moved between a maintenance draft Wm and an operations draft Wo. The invention shall not be restricted to this type of fish farming plant, as the skilled person readily will understand that other buoyancy means and net cage suspension configurations are conceivable.

Figure 1 shows a first embodiment of a fish farming plant 10 comprising a first net cage

17. The first net cage 17 is suspended below a buoyant structure 11, 12, 13. The first net cage 17 may comprise a generally cylindrical portion 17a and a respective conical portion 17b below the cylindrical portion 17a. A foundation element 16 is arranged at the transition between the two portions 17a,17b and suspended by a suspending element

DK 2022 70471 A1 6

15. The foundation element 16 may thus also be generally ring-shaped. The suspending element 15 may be one or more cables such as ropes, wires, chains, etc. connecting the foundation element 16 to the buoyant structure 11,12,13. Alternatively, the suspending element 15 may also be a rigid and stiff element. The first net cage 17 is releasably s connected to the foundation element 16, and the foundation element 16 thus maintains the shape of the first net cage 17. The foundation element 16 may therefore have a certain stiffness and negative buoyancy in order to withstand loads imposed by the body of water and marine life, inside and outside the net cage 17. As a non-limiting example, the foundation element 16 may be constructed by steel pipes and filled with concrete to have a wet weight of 200 tonnes. It should be understood that the foundation element 16 may be an integrated part of the suspending element 15, the foundation element 16 may be arranged between the first net cage 17 and the suspending element 15, or the foundation element 16 may even be arranged outside the suspending element 15. Figure 1 further shows that a plurality of connector devices 20 are installed on the is foundation element 16. The figure illustrates a system having sixteen connector devices 20, but the invention is not limited to this number. The connector devices 20 allow the first net cage 17 to be easily disconnected from the foundation element 16, and the first net cage 17 may therefor be hoisted up to the buoyant structure 11,12,13 for cleaning, repair, etc., while the foundation element 16 is suspended by the suspending element 15.

This is described more in detail later. Figure 2 shows a second embodiment of a fish farming plant 10’. In the second embodiment, the suspending element 15 is a second net cage. The foundation element 16 is thus suspended by the second net cage. The first, inner net cage 17 is arranged within the suspending element 15, both net cages being suspended below the buoyant structure 11,12,13. Each net cage 15,17 comprises a respective cylindrical portion 17a, 15a and a respective conical portion 17b, 15b below the cylindrical portion. It should be understood that the foundation element 16 may be an integrated part of the second net cage 15, it may be arranged between the first net cage 17 and the second net cage 15, or the foundation element 16 may even be arranged outside the second net cage 15.

The suspending element 15, being an outer net cage, protects the first net cage 17 from damage from predators and floating objects and serves as a secondary barrier. However,

DK 2022 70471 A1 7 the invention shall not be limited to such functional features for the suspending element 15, as it in fact may be any suitable object arranged around the first net cage 17, as described with reference to figure 1. Figure 3 illustrates the net cage system in more detail, and shows the connector device s 20 installed on the foundation element 16. In the illustrated embodiment, the foundation element 16 comprises a plurality of straight built-up tubulars of a suitable metal grade (e.g. VL E36), welded together via a metal plate. Extending between the connector device 20 and the first net cage 17 is a rope, hereinafter referred to as a tether, 19. For the purposes of this description, the tether may comprise a rope, strap, wire, chain, or other element having the required strength for the intended purpose.

Figure 4 illustrates a configuration in which the tether 19 is connected to a bridle 19a,b which in turn is connected to respective portions of the first net cage 17. In the illustrated embodiments, the tether 19 or bridle 19a,b are connected to the first net cage 17 at or near the transition between the cylindrical portion 17a and the conical portion 17b. Individual ropes, straps, or similar 5 are connected to the bridle or the transition and are further connected loosely to the inner net up to a location above the body of water (not shown, e.g. the lower pontoon) where they may be connected to handling winches (not shown). These handling winches may be used for raising and lowering the first net cage 17 in the body of water, as indicated by the double arrow “n”.

Also illustrated by figure 3 is an elongate manipulation element 18, which extends between the connector device 20 and a location from where it may be operated. Thus, the elongate manipulation element 18 may be connected to a drum and/or a winch (not shown) on a location above the body of water (not shown, e.g. the upper or lower pontoon), or to a position in the body of water. The elongate manipulation element 18 may be moved up and down as indicated by the double arrow “m”, and is used in conjunction with the above mentioned raising and lowering of the first net cage 17. The elongate manipulation element 18 may be a line, rope, wire or other suitable cable. The elongate manipulation element 18 and the tether 19 are interconnected via the connector device 20, as will be explained below. As the tether (and bridle) 19 is designed for connecting the first net cage 17 to the foundation element 16 during operation of the fish farming plant, it must be capable of handling large dynamic loads (for example

DK 2022 70471 A1 8 approximately 120 tonnes). The elongate manipulation element 18, on the other hand, is only used to assist in raising and lowering the first net cage 17, and may have a smaller load capacity (for example approximately 6 tonnes). Figure 3 also illustrates how the connector device 20 may be operated by an ROV (Remotely Operated Vehicle) 4. It will be understood that the connector device 20 may also be operated by other types of underwater vehicle or implement, or by a diver. Although not illustrated specifically, it should be understood that the net cage system may comprise several such sets of elongate manipulation element 18, connector device 20, and tether 19.

A first embodiment of the connector device 30 will now be described with reference to figures 5 and 6. In this embodiment, the connector device 30 comprises a manipulator element 35 having a tool interface portion 34 at a first end and a locking device 33 ata second end. The manipulator element 35 is movable back and forth between a locked state and an unlocked state by operation (e.g. rotation to generate a torque) of the tool interface portion 34. The elongate manipulation element 18 and the tether 19 are interconnected via link element 32 and are supported by a bend shoe 31 on the connector device. The bend shoe 31 is preferably provided with a lining (e.g. nylon) having low friction. In the illustrated embodiment, the manipulator element 35 extends through a designated duct in the foundation element 16. Figure 5 illustrates the connector device in a locked state, in which the tether is fixed to the foundation element 16 via the connector device and thus contributes to securing the first net cage 17 to the foundation element 16. In this state, the elongate manipulation element18 does not carry any loads from the first net cage 17, and may therefore be inactive. Figure 6 illustrates the connector device 30 in an unlocked state, wherein the elongate manipulation element18 and tether 19 are structurally and functionally interconnected. That is, in this unlocked state, any movement of the first net cage 17 influences the manipulation line- and-tether combination, and vice versa, as indicated by the arrows in figure 6. In this state, the first net cage 17 may for example be raised to a position above the body of water (e.g. for repair, maintenance or replacement) while the elongate manipulation elementl8 is paid out correspondingly. Conversely, installation of a first net cage 17 is performed by pulling on the elongate manipulation element18 while the inner cage is

DK 2022 70471 A1 9 simultaneously lowered into the water, until the link element 32 may be locked in the connector device 30. A second embodiment of the invented net cage system and connector device will now be described with reference to figures 7 to 9. In this embodiment, the connector device 40 comprises a manipulator element 45 having a tool interface portion 44 at a first end and being connected to a locking device 43 at a second end.

In the illustrated embodiment, the locking device 43 comprises a bell crank which is rotatably connected to a support 6 on the foundation element via a pivot 43d.

A first bell crank arm 43a is connected to the manipulator element and a second bell crank arm 43b comprises a detent portion 43b configured for locking engagement with a link element 42. The link element 42 is at one end connected to the manipulation line and may at a second end be connected to the tether 19. The elongate manipulation element 18 passes around a sheave 41 which is rotatably connected to the support 6 via a pivot 41a.

A spring element 46 extends between the bell crank arms and provides a biasing force against a portion of the locking device 43, thus preventing the locking device from inadvertently dislodging from the detent 43c when the connector device is in a locked state.

The manipulator element 45 is movable back and forth between a locked state (figures 7 and 8) and an unlocked state (figure 9) by operation of the tool interface portion 44. In the illustrated embodiment, the manipulator element 45 extends through a locking frame 45 and comprises a locking interface portion 45b which serves to fix the manipulator element 45 in the locked state or unlocked state.

When the connector device is in a locked state and the tether 19 is fixed to the foundation element 16 via the connector device, it contributes to securing the first net cage 17 (not shown in figures 7-9) to the foundation element.

In this state, the elongate manipulation element 18 does not carry any loads from the first net cage 17, and may therefore be inactive.

Figure 9 illustrates the connector device 40 in an unlocked state, wherein the elongate manipulation element 18 and tether 19 are structurally and functionally interconnected.

That is, in this unlocked state, any movement of the first net cage 17 influences the manipulation line-and-tether combination, and vice versa.

In this state, the first net cage 17 may for example be raised to a position above the body of water (e.g. for repair, maintenance or replacement) while the elongate manipulation element 18 is paid out

DK 2022 70471 A1 10 correspondingly. Conversely, installation of a first net cage 17 is performed by pulling on the elongate manipulation element 18 while the first cage is simultaneously lowered into the water, until the link element 32 may be locked in the connector device 40. Although not illustrated, the connector device 40 may be furnished with guide funnels for the tether and/or for the elongate manipulation element, in order to improve the transmission of any lateral forces into the connector device 40 and foundation element

16. A third embodiment of the net cage system and connector device will now be described with reference to figures 10 to 18. Figure 10 illustrates the connector device 50 according to the third embodiment installed on a foundation element 16, as described above Figure 12 illustrates a manipulator element 55, having a tool interface portion 54, a locking interface portion 55b and a connection portion 55c. In this embodiment the manipulator element 55 is formed of a spring element, preferably a plate spring. When the manipulator element 55 is installed in the connector device 50 as shown in figure 11, the connection portion 55c is movably connected to a locking device 53 (which is described in more detail below) and the locking interface portion 55b is arranged in a locking slot 55a in the support 6. The locking slot 55a comprises two separated grooves, in which a first groove 55a is closer to the foundation element that a second groove 55a; (see also figures 15 and 16). When the locking interface portion 55b is placed in the second groove 55a; (see figures 11 and 16), the manipulator element (spring) 55 is compressed and loaded less than when the locking interface portion 55b is placed in the first groove 55a; (see figure 15). Figure 13 illustrates the above mentioned locking device 53, which comprises an engagement portion 53c configured for locking engagement with an engagement structure 52c on a link element 52 (see figure 14), a portion 53a configured for movable connection with the connection portion 55c, and an intermediate pivotable section 53d for rotatable connection to the support 6 (discussed above). Therefore, when the locking interface portion 55b is placed in the second groove 55a; (a locked state of the connector device; figure 16), the locking device 53 is rotated in the clockwise direction, and when the locking interface portion 55b is placed in the first groove 55a; (an

DK 2022 70471 A1 11 unlocked state of the connector device; figures 11 and15), the locking device 53 is rotated in the counter-clockwise direction.

In an alternative embodiment, the portion 53a may be connected to a cable (or similar connection means) connected to a location above the water.

The locking device 53 may as such be controlled and activated by the cable from a location above the water.

The cable may e.g. be connected to the connector device 50 by being routed over a sheave and connected to the portion 53a such that upon pulling the cable, the portion 53a is manipulated correspondingly as if it was moved by the connection portion 55c (see figure 11). Figure 14 illustrates the above mentioned link element 52, here in the form of a rod having a first end 52a for connection to the tether 19 (not shown in figure 14), a second end with an interface opening 52b for connection to the elongate manipulation element 18 (not shown in figure 14), and an intermediate engagement structure 52c for engagement with the engagement structure 53c on the locking device 53. A wedge- shaped portion 52d is arranged near the first end 52a.

An opening 52d is connected to the interface opening 52b via an internal bore and serves as a channel for securing the elongate manipulation element 18 to the link element 52 (as shown in figure 11). As illustrated in figure 11, the link element (rod) 52 is at one end connected to the elongate manipulation element 18 and at a second end connected to the tether 19. The elongate manipulation element 18 passes around a sheave 51 which is rotatably connected to the support 6 via a pivot 51a.

The manipulator element 55 is movable back and forth between a locked state (figure 16) and an unlocked state (figures 11 and 15) by operation of the tool interface portion 54 as described above.

In the illustrated embodiment, the manipulator element 55 extends around the foundation element t 16, and the tool interface portion 54 is thus arranged on a portion of the foundation element facing away from the net cages.

More specifically, the tool interface portion 54 is arranged on the outside of the outer net cage 15, where it is easily accessible to a diver or an ROV.

Common to the embodiments described above, when the connector device 50 is in a locked state and the tether 19 is fixed to the foundation element 16 via the connector device (figures 11 and 16), it contributes to securing the first net cage 17 to the foundation element 16. In this state, the elongate manipulation element 18 does not

DK 2022 70471 A1 12 carry any loads from the first net cage 17, and may therefore be inactive.

Figure 15 illustrates the connector device 50 in an unlocked state, wherein the elongate manipulation element 18 and tether 19 are structurally and functionally interconnected.

In this state, the first net cage 17 may for example be raised to a position above the body of water (e.g. for repair, maintenance or replacement) while the elongate manipulation element 18 is paid out correspondingly.

Conversely, installation of a first net cage 17 is performed by pulling on the elongate manipulation element 18 while the inner cage is simultaneously lowered into the water, until the link element 52 may be locked in the connector device 50. The guide funnels for the tether and/or for the manipulation line, in order to improve the transmission of any lateral forces into the connector device and foundation element 16. Figures 17 and 18 illustrate two stages of a sequence for connecting the first net cage to the connector device (and hence the foundation element). In figure 17, the elongate manipulation element 18 is pulled as described above (indicated by the arrow on item 18), for example by a winch on one of the pontoons, and the first net cage 17 is lowered correspondingly.

The link element 52 is being pulled into a receptacle 57, and the wedge-shaped portion 52d is abutting against the engagement portion 53c and thus forces the spring-loaded locking device 53 to move.

Once the link element 52 has been pulled sufficiently far into the receptacle 57, the engagement portion 53c snaps into the engagement structure 52c (as shown in figures 11 and 16) and establishes a firm (locked) connection between the link element and the connector device.

When the link element is to be disconnected from the connector device, a slight tension is applied to the elongate manipulation element 18 to pull the connector device a small distance into the receptacle, and the manipulator element 55 is operated by the tool interface portion 54 to move the engagement portion 53c out of the engagement structure 52c.

As this stage, the inner net may be raised towards the surface while the elongate manipulation element 18 is paid out.

All embodiments of the invention described above realize the common principle that the first net cage 17 may be released from — and connected to — the foundation element 16 by an operator (e.g. a diver or an ROV) located outside the suspending element (second

DK 2022 70471 A1 13 net cage) 15. Alternatively, there may also be actuators on the connector devices such that the connector devices may be controlled by acoustic signals, hydraulics, pneumatics or electricity. The connector devices may alternatively be controlled by a release cable connected to the buoyant structure.

The foundation element 16 comprises a plurality of connection devices 20, 30, 40, 50, arranged at intervals on the foundation element and located inside the outer net cage. For each connection device, a portion of the manipulator element 35, 45, 55 has a tool interface portion 34, 44, 54 which extends from the connection device to a position outside the outer net cage.

The skilled person will understand that the components are manufactured from materials suitable for their purpose. In general, parts that may be effectively protected by cathodic protection are based on carbon steel. Parts that cannot be protected by cathodic protection may be stainless steel, e.g. 25Cr duplex or be made of non-metallic materials such as PE, GRP or PA6. The invention shall, however, not be limited to such materials.

In the embodiments described above, various features and details are shown in combination. The fact that several features are described with respect to a particular example should not be construed as implying that those features by necessity have to be included together in all embodiments of the invention. Conversely, features that are described with reference to different embodiments should not be construed as mutually exclusive. As a person skilled in the art readily will understand, embodiments that incorporate any subset of features described herein and that are not expressly interdependent have been contemplated by the inventor and are part of the intended disclosure. However, explicit description of all such embodiments would not contribute to the understanding of the principles of the invention, and consequently some permutations of features have been omitted for the sake of simplicity or brevity. Although the above description of the invention refers to the elongate manipulation element (line) 18 being operated from a location above the water — such as by a winch and drum located on one of the pontoons, it should be understood that the ma elongate

DK 2022 70471 A1 14 manipulation element 18 also may be operated from a subsea location, for example by a winch and drum arranged on the foundation element.

Several shapes for the foundation element 16 are conceivable, as long as the element is a structural element that fulfills the criteria of maintaining the shape of the net cages, as s described above.

Also, while the connector device 20; 30; 40; 50 has been described as being mounted directly on the foundation element 16, it should be understood that the connector device may be mounted on any suitable foundation connected to the suspending element 15.

Claims

DK 2022 70471 A1 15 Claims I. A fish farming plant (10; 107) comprising: - a first net cage (17) suspended from a buoyant structure (11, 12, 13); - a foundation element (16) suspended from the buoyant structure (11, 12, 13) by a suspending element (15); - a plurality of tether elements (19) connected at a first end to the first net cage (17) and at a second end to respective link elements (32; 42; 52), each said link element (32; 42; 52) being connected to a respective elongate manipulation element (18); - a plurality of connector devices (20; 30; 40; 50) arranged on the foundation element (16); - each connector device (20; 30; 40; 50) comprising a releasable locking device (33; 43; 53) configured for selective releasable connection with a portion of the link element (32; 42; 52), and a manipulation element (35; 45; 55) connected to and configured for operating the locking device (33; 43; 53).
2. The fish farming plant (10; 107) of claim 1, wherein the connector devices (20; 30; 40; 50) and the foundation element (16) are arranged between the first net cage (17) and the suspending element (15), and the manipulation element (35; 45; 55) comprises a tool interface portion (34; 44; 54) arranged on an opposite side of the suspending element (15) from its respective connector device (20; 30; 40; 50), whereby the locking device may be operated by a diver or a ROV located outside the suspending element (15).
3. The fish farming plant (10') of any one of claims 1-2, wherein the suspending element (15) is a second net cage, and the first net cage (17) is nested within the second net cage (15).
4. The fish farming plant (10; 107) of any one of claims 1-3, wherein the foundation element (16) is a ring element with negative buoyancy.
5. The fish farming plant (10; 107) of any one of the previous claims, wherein the elongate manipulation element (18) is a cable.

DK 2022 70471 A1 16
6. The fish farming plant (10; 107) of any one of the previous claims, wherein the elongate manipulation element (18) is connected to the buoyant structure (11, 12, 13) and configured for manipulation from the buoyant structure (11, 12, 13).
7. A method of raising a first net cage (17) in a fish farming plant (10; 10’) according to any one of claims 1-6, comprising: - operating the plurality of manipulation elements (35; 45; 55) to release the corresponding link elements (32; 42; 52) from their respective connector device (20; 30; 40; 50); and - raising the first net cage (17) to a desired location in or above the water while controllably paying out on the respective elongate manipulation element (18).
8. A method of installing a first net cage (17) in a fish farming plant (10; 107) according to any one of claims 1-6, comprising: - applying tension to the plurality of elongate manipulation elements (18) while lowering the first net cage (17) into the body of water until the corresponding link element (43; 52) is pulled into locking engagement in its respective connector device (40; 50).
9. The method of claim 8, wherein the manipulation elements (35; 45; 55) are operated to secure the corresponding link elements in their respective connector device (40; 50).
10. — The method of any one of claim 7 or claim 9, wherein the manipulation elements (35; 45; 55) are operated by one or more divers or ROVs located outside the suspending element (15).