The invention relates to a vessel for cleaning a submerged structure. More particularly, the invention relates to a vessel with a propelling means of its own. The vessel is arranged to follow a structure along a water line and, by means of a cleaning device, 5 clean the submerged part of the structure. The vessel is adapted for supplying the cleaning device with a pressurized fluid, such as water. The vessel is further arranged to lower and lift the cleaning device to a desired depth in a water column, and to move the cleaning device sideways along the submerged structure.

For the farming of fish, floating cages may be used. A so-called open cage includes, i o inter alia, a floating body encircling an enclosure for the fish. The enclosure may consist of a seine. The seine is closed at the bottom. The water flows freely through the seine. The fish is dependent on the water inside the seine being renewed by flow- through for the oxygen content in the water to be satisfactory. Over time, the seine will become covered with fouling and the water flow-through decreases. The oxygen 15 content inside the net pen decreases, which is unfortunate for the welfare, health and growth of the fish.

It is known to use so-called cleaner fish in net pens to fight crustacean ectoparasites on the fish. Salmon lice are one example of such a parasite. It is beneficial to keep the seine clean of fouling in order to have the best effect of the cleaner fish. The cleaner 20 fish will eat from the fouling and will therefore not be so active in eating salmon lice when the seine is fouled.

It is known in the trade to treat seines that are used for net pens with impregnating agents to prevent fouling. Such impregnating agents are inherently toxic. Known impregnating agents include cupriferous impregnating agents. It is also known that such 25 seines will have to be sent to special cleaning facilities for cleaning and reimpregna- tion. This is an extensive operation which includes, inter alia, mobilizing a boat with a crane to lift the seine out of the sea and to put the seine back into the sea. An alternative to washing and impregnating the seines is washing the seines in situ. The patent document US 2011/0185519 shows a device for cleaning a submerged net, in particular a net in a fish pen. The device is operated from a surface vessel. The device comprises a rectangular or square chassis which is adapted for sliding across the 5 net, buoyancy bodies that are placed within the frame, a propulsion member for

moving the device along the net, a propeller for keeping the device up to and in contact with the net, and a cleaning member. The cleaning member may include a suction device integrated in the chassis, or a high-pressure washer. In addition, the device may be provided with brushes. The propulsion member may include hydraulically driv- i o en toothed wheels. The propeller may be hydraulically driven. The buoyancy body is adapted for the device, in its fully submerged position, to have a negative buoyancy of about 10 kg. Patent document EP 2251102 discloses another device for cleaning a submerged net. The device is a device running on wheels and is securely held from the surface. Power is supplied from the surface through a cable, and pressurized liquid

15 is supplied from the surface through a hose. Cleaning is performed by high-pressure washing the net. Patent document WO 2015/005801 discloses an autonomous device for cleaning a submerged net. The device includes wheels for propulsion across the net, a propeller for positioning the device against the net, rotating brushes for cleaning, buoyancy means and a battery for power supply. It is also known to use devices

20 provided with tracks as an alternative to wheels.

It is also known to use a cleaning device including a chassis provided with one or more rotating discs for cleaning nets. Water under high pressure is carried up to the centre of each rotating disc. Each disc has channels from the centre to the periphery of the disc. The channel ends in a slanted nozzle, so that the disc is brought to rotate when

25 water under high pressure is flowing out of the nozzle opening . The rotating motion of the water jet is advantageous for loosening fouling from the net. The rotating motion also creates a negative pressure on the side of the rotating disc facing in towards the net, so that the device is kept up to the net. The cleaning device is moved down and up along the inside of the net one or more times until this portion of the net has been

30 cleaned. Then the cleaning device is moved sideways to clean the next portion. A

cleaning device with one or two discs may be operated manually. A larger cleaning device is moved with the help of a crane on a work vessel. The cleaning device is securely held with a wire or a rope, water under high pressure is carried up to the cleaning device in a high-pressure hose, and an electrical wire carries energy and signals, if

35 any, to other equipment on the chassis, such as a camera. Some of the known devices have, inter alia, the drawback of having to be operated from the surface, from a work boat. The work boat preferably has a crane. Because of the work of mobilizing a boat and crew, cleaning will not be carried out until the fouling has become relatively extensive. There is therefore a need for a device and a method that can clean the seine regularly and before the fouling has become extensive.

It is a known problem that holes or tears may arise in this type of seines. The fish in the enclosure may swim out through such a hole. There is therefore a need to be able to discover such holes or tears as early as possible. The hole or tear must be located; where in the seine wall it is in the longitudinal direction of the seine wall, and at what depth.

Even though the net pen has a relatively large radius, the seine wall of the net pen will not appear as a plane surface. Because of water currents, the seine wall will form bulges and folds. This makes a cleaning device that is moving with wheels in contact with the seine wall lose contact with the seine wall in some portions. Cleaning devices with rigid chassis will not clean in folds and bulges.

It is common for net pens to be provided with so-called bird nets to keep predatory birds away from the fish in the enclosure. The bird net is extended over the entire surface of the net pen. The bird net is held up by a tower positioned at the centre of the net pen, and the bird net is secured to the railing encircling the enclosure. To be able to clean the seine from the inside with a device as described in patent document US 2011/0185519, for example, or a device with rotating discs, the bird net will have to be loosened from the railing as the device is being moved sideways along the seine wall.

The invention has for its object to remedy or reduce at least one of the drawbacks of the prior art or at least provide a useful alternative to the prior art.

The object is achieved through the features which are specified in the description below and in the claims that follow.

The invention is defined by the independent claim. The dependent claims define advantageous embodiments of the invention.

The invention relates, more specifically, to a vessel for cleaning a submerged structure, the vessel including a buoyancy means, and the vessel being provided with : - at least one guide for contact against a buoyancy body or a surface of the sub- merged structure;

- at least one drum provided with a conduit for pressurized fluid;

- a motor for driving a pump for the pressurized fluid and for driving the drum; and

- a cleaning device connected to the free end portion of the conduit.

5 The vessel may consist of a raft. The buoyancy means may comprise a hull or some other buoyancy body.

The vessel my further include a service conduit which is attached, at its free end portion, to the cleaning device, the service conduit being separated from the conduit for the pressurized fluid. By separated is meant in this description that the two conduits i o do not lie against each other, for example by being bundled together. The two conduits are spaced apart and will move independently of each other in a water column. The service conduit may have the same diameter as the conduit for the pressurized fluid. The service conduit may be reeled onto the same drum as the pressurized conduit.

15 The guide may include a wheel. The guide may include a pair of wheels. The wheel may be driven by a motor. The pair of wheels may be driven by a motor. The wheel may include a counter. The vessel may be provided with an arm for holding the wheel or pair of wheels. The arm may be vertically movable.

The vessel may be provided with a counter for measuring the length of conduit paid 20 out from the drum.

The submerged structure may consist of a net. The net may be a net in a net pen. The buoyancy body may be a buoyancy body for a net pen and may comprise a floating ring. In an alternative, the submerged structure may consist of a hull of a vessel. The hull of the vessel may constitute the buoyancy body. The submerged structure may 25 consist of a fixed marine installation, such as a concrete structure. A fixed marine installation like that is not provided with any buoyancy body and the guide of the vessel follows the marine installation along the water line.

The pressurized fluid may consist of pressurized water or sea water. The pressurized fluid may alternatively comprise pressurized water or sea water with an added abra- 30 sive material. The pressurized fluid may alternatively comprise pressurized gas, such as air.

A cleaning device for cleaning a submerged structure wherein the cleaning device may have a longitudinal axis, a coupling side and a washing side is described as well, and the cleaning device may comprise:

- a frame;

- at least one rotatable disc with at least one nozzle opening for a pressurized fluid; and

5 - a coupling for connection to a free end portion of a conduit for the pressurized fluid, the coupling being rotatably attached to the cleaning device.

The pressurized fluid may consist of pressurized water or sea water. The pressurized fluid may alternatively comprise pressurized water or sea water with an added abrasive material. The pressurized fluid may alternatively comprise pressurized gas, such i o as air.

The cleaning device may be provided with a change-over mechanism for keeping the coupling fixed in a desired orientation relative to the longitudinal axis of the cleaning device.

A coupling section may be adapted for the connection of one free end portion of a ser- 15 vice conduit separated from the conduit for the pressurized fluid.

The cleaning device may be provided with a coupling section and an end section and the end section may be hingedly attached to the coupling section. The end section may be foldable towards the coupling side. The end section may be foldable towards the washing side.

20 The coupling section may be adapted for the connection of one free end portion of a service conduit which is separated from the conduit for the pressurized fluid.

A cleaning device for cleaning a submerged structure wherein the cleaning device may have a longitudinal axis, a coupling side and a washing side is described as well, and the cleaning device may comprise:

25 - a frame;

- at least one rotatable disc with at least one nozzle opening for a pressurized fluid; and

- a coupling for connection to a free end portion of a conduit for the pressurized fluid, and wherein the cleaning device may be provided with a coupling section and an end

30 section, and the end section may be hingedly attached to the coupling section.

The end section may be foldable towards the coupling side. The end section may be foldable towards the washing side. The cleaning device may be provided with a rotatabie coupling secured to the cleaning device. The cleaning device may be provided with a change-over mechanism for keeping the coupling fixed in the desired orientation relative to the longitudinal axis of the cleaning device.

5 A coupling section may be adapted for the connection of one free end portion of a service conduit separated from the conduit for the pressurized fluid.

In what follows, examples of preferred embodiments are described, which are visualized in the accompanying drawings, in which :

Figure 1 shows a vessel in a perspective view, the vessel being provided with a i o cleaning device, and the cleaning device being shown with its longitudinal axis oriented horizontally;

Figure 2 shows a side view, on a larger scale, of the vessel and the cleaning device shown in figure 1;

Figure 3 shows the same as figure 1, but the cleaning device is shown with its 15 longitudinal axis oriented vertically;

Figure 4 shows the same as figure 2, but the cleaning device is shown with its longitudinal axis oriented vertically;

Figures 5A-B show, on a larger scale, a side view (A) and a top view (B) of the cleaning device in a first position of application;

20 Figures 6A-B show, on the same scale as figures 5A-B, the cleaning device in a second position of application, in which the frame of the cleaning device has been folded towards a coupling side; and

Figures 7A-B show, on the same scale as figures 5A-B, the cleaning device in a third position of application, in which the frame of the cleaning device has 25 been folded towards a washing side.

In the figures, the reference numeral 1 indicates a vessel. The vessel 1 comprises a hull 2, at least one drum 29 for storing at least one conduit 3 for a pressurized fluid, a guide 4 and a propulsion means 5. The vessel 1 further includes at least one motor (not shown) for driving the at least one drum, for driving the propulsion means 5 and 30 for driving a pump (not shown) for pressurizing the fluid. The at least one conduit 3 is connected, at its free end portion 30, to a cleaning device 6. The cleaning device 6 includes at least one coupling 61 for the conduit 3. The cleaning device 3 further includes a frame 62 and at least one washing device 7. In one embodiment, the frame 6 may be a rigid frame 6. In an alternative embodiment, the 5 frame 6 may be provided with at least one articulation 63 so that the frame 6 is folda- ble as shown in figures 6A-B, 7A-B.

In the figures, a vessel 1 provided with one conduit 3 is shown. The cleaning device 6 is shown with six washing devices 7. The cleaning device 6 has negative buoyancy. The vessel 1 is further provided with a service conduit 32. At its free end portion 320, i o the service conduit 32 is connected to the cleaning device 6.

The vessel 1 is provided with a drum casing 21 enclosing the drum 29, the reeled conduit 3 and the reeled service conduit 32. In one edge, the drum casing 21 is provided with an opening 22 through which the conduit 3 and the service conduit 32 have been passed. The vessel 1 is also provided with a guiding device 23 of a kind known per se,

15 moving in the longitudinal direction of the drum casing 21 to reel the conduit 3 and the service conduit 32 onto or off the drum 29 as is shown in the enlarged section in figure 1. The conduit 3 and the service conduit 32 have each been passed through a respective guide arrangement 24 and over a respective sheave 25 oriented substantially vertically in a position of application. The sheave 25 is attached to a bracket 26

20 so that the sheave 25 projects from the hull 2. The guide arrangement 24 is shown as a pair of opposite pulleys 27, so that the conduit 3 and the service conduit 32 are each guided between a respective pair of pulleys 27 in a manner known per se. It is advantageous that the conduit 3 and the service conduit 32 are of the same diameter because both conduits 3, 32 may then be reeled onto one drum 29 at the same speed.

25 The guide 4 is adapted for the vessel 1 to be guided along a buoyancy body (not

shown) or another surface at the water line. The buoyancy body may be a buoyancy body for a net pen (not shown). The buoyancy body may be circular and consist of a continuous tube, as is known in the trade. The vessel 1 may be provided with two guides 4. Each guide 4 may comprise at least one wheel 41. In the figures is shown

30 that each guide 4 comprises a pair 42 of wheels. The two wheels 41 of the pair 42 of wheels may be connected to an axle 43. The axle 43 is attached to the hull 2 with an arm 44. One of the wheels 41 may be provided with a motor 45, as is shown in figures 2 and 4. The motor 45 may be an electric motor which is supplied with electrical power from a generator (not shown) driven by the motor not shown. In an alternative

35 embodiment, the motor 45 may be a hydraulic motor. Each wheel 41 of the pair 42 of wheels may be driven jointly by the motor 45. The wheels 41 rest against the buoyancy body or the surface at the water line. The motor 45 makes one wheel 41 or both wheels 41 rotate, and thereby the vessel 1 will move sideways along the buoyancy body or the surface at the water line. The wheel 41 may also be provided with a 5 counter (not shown) to indicate the position of the vessel 1 along the buoyancy body or the surface at the water line.

The arm 44 may be movably attached to the hull 2. The arm 44 may especially be vertically movable. This allows the vessel 1 to move in waves independently of the movement of the buoyancy body in the same waves. This ensures good contact be- i o tween the wheel 41 and the buoyancy body. In the figure, the attachment of the arm 44 to the hull 2 is hidden behind a cover 46.

On its bottom side, the hull 2 is provided with a protective frame 28. The protective frame 28 surrounds the propulsion means 5. The propulsion means 5 is shown as a V- thruster 51 of a kind known per se. The propulsion means 5 may comprise a plurality

15 of V-thrusters 51, as is shown in figures 2 and 4. It may be advantageous for the propulsion means 5 to comprise four V-thrusters 51 arranged in pairs and in such a way that one pair is oriented perpendicularly to the other pair. Such an arrangement of the V-thrusters 51 gives the vessel 1 good manoeuvrability so that the vessel 1 can be kept stationary up to the buoyancy body. The propulsion means 5 may also move the

20 vessel 1 sideways along the buoyancy body.

The cleaning device 6 is shown with a change-over mechanism 64 on its coupling side 60. The coupling 61 is rotatably attached to the cleaning device 6. By means of the change-over mechanism 64, the coupling 61 can be rotated and locked in such a way that the conduit 3 and the service conduit 32 are brought in perpendicularly to the

25 longitudinal axis of the cleaning device 6, as is shown in figures 1 and 2, or the conduit 3 and the service conduit 32 are brought in substantially parallel to the longitudinal axis 68 of the cleaning device 6, as is shown in figures 3 and 4. The cleaning device 6 is kept stable in the orientation chosen, by means of the conduit 3 and the service conduit 32. This is achieved by the conduit 3 and the service conduit 32 being

30 separated from each other, and by the conduit 3 and the service conduit 32 being oriented side by side in a water column.

The coupling 61 includes an inlet 65, as shown in figures 5A-B, 6A-B and 7A-B, which is attached to the free end portion 30 of the hose. The inlet 65 comprises an inlet opening 651 and a swivel 653. The coupling 61 further includes a circular base 66 35 which is rotatably attached to a circular attachment frame 67 on the coupling side 60 of the cleaning device 1. The attachment frame 67 is shown with a plurality of bearings 671 for the circular base 66.

On its coupling side 60, the cleaning device 6 is shown provided with a plurality of couplings 72 for the pressurized fluid. In the figures, one coupling 72 is shown for each washing device 7. The coupling 72 may be provided with threads 73 as shown in detail in figure 7A. The washing device 7 includes a rotatable disc 74. In the disc 74 is formed at least one channel (not shown) from the centre portion 75 of the disc 74 to the edge portion 76 of the disc. In the edge portion 76, the channel forms a slanted nozzle opening 77, as shown in the enlarged section in figure 3. Pressurized fluid flows through the coupling 72 and a swivel 78, through the channel in the disc 74 and out of the nozzle opening 77. As the nozzle opening 77 is slanted, the disc 74 is brought to rotate. Several discs 74 with their nozzle openings 77 are arranged in such a way that the jet formed by the pressurized fluid, overlaps with the jet from the neighbouring disc 74.

In figures 5B, 6B and 7B, two hoses 34 are shown between the swivel 653 and two couplings 72. The figures do not show the hoses interconnecting the other couplings 72.

The frame 6 is shown with several articulations 63 so that it is foldable. The articulations 63 are positioned between the coupling section 621 and the end section 623 of the cleaning device 6. The articulations 63 are of such a kind that the end section 623 can be folded towards the coupling side 60 as shown in figure 6A and that the end section 623 can be folded towards the washing side 69 as shown in figure 7A. The articulations 63 are further of such a kind that they are bent passively as the frame 6 is being moved across the surface. The articulations 63 are further of such a kind that they move the end section 623 towards the coupling section 621 along the longitudinal axis 68 when the end section 623 is folded towards the coupling side 60 as shown in figure 6A. Thereby an overlapping by the jet of high-pressure fluid from a disc 74 in the coupling section 621 with the jet from the neighbouring disc 74 in the end section 623 is achieved, also when the discs 74 are not in the same plane as shown in figure 6A.

The cleaning device 6 may further be provided with thrusters (not shown) for pressing the frame 6 harder in towards the seine wall. Such thrusters may be driven by the pressurized fluid in the conduit 3. In an alternative, such thrusters may be electrically driven and they may be supplied with electrical energy from the service conduit 32. The cleaning device 6 may further be provided with a collecting tool (not shown) for collecting material washed off the net. The collecting tool may comprise a pump which, on the suction side of the pump, sucks water and material through an opening 8 in the cleaning device 6. The pump is attached to the coupling side 60 of the clean- 5 ing device 6. On its pressure side, the pump is connected to a hose (not shown)

extended up to a water surface 9. The hose discharges into a collector (not shown). The collector may be positioned in the vessel 1 or may float in some other way at the water surface 9. The pump may be driven by the pressurized fluid in the conduit 3. In an alternative, the pump may be electrically driven and be provided with electrical i o energy from the service conduit 32.

The cleaning device 6 may further be provided with an underwater camera or an underwater video camera (not shown). The camera or video camera may be provided with a signal cable in the service line 32. Thereby, an operator who receives signals from the vessel 1 can monitor the seine wall and discover damage, for example holes 15 or tears. The cleaning device 6 may further include a depth sensor (not shown). The depth sensor may indicate the depth of the cleaning device 6 relative to the water surface 9. This may be in addition to the vessel 1 including a counter which shows how much conduit 3 and service conduit 32 has been paid out from the drum 29.

The vessel 1 may further include a GPS to determine the position of the vessel 1. The 20 GPS, together with the counter on the wheel 41, will give an accurate position of the vessel 1 relative to the net pen. This may be logged in a manner known per se and be a basis for reporting which parts of the net wall have been cleaned and when this was carried out. Together with data from the depth meter and/or counter for the paying- out of the cable 3, it may also be documented how deep the cleaning has been carried 25 out.

The pressurized fluid may be water. The vessel 1 may be provided with a submerged inlet for water, preferably sea water (not shown). The inlet may be provided with a filter. In an alternative embodiment, the pressurized fluid may be a gas, such as air. In this embodiment, the inlet is positioned above the water surface 9. For some fields 30 of use, it may be advantageous if the vessel is provided with means for adding an abrasive material to the pressurized water.

The vessel 1 may also include a system for image recognition, so that holes or tears discovered in the net will set off a warning. This may also be compared with positional data from the GPS and/or counter on the wheel 41 and data from the depth meter and/or the counter for paying out the cable 3, so that an accurate position of the hole or tear may be reported . This may also be logged and documented.

The person skilled in the art will understand that the vessel 1 includes the necessary control systems and communications systems for measuring and recording data.

Communication may happen wirelessly or by cable. The vessel 1 may further be manually controlled or be autonomous.

The vessel 1 may be positioned on the inside of a net pen or on the outside of a net pen. When the vessel 1 is to be positioned on the inside of a net pen, the vessel 1 is lifted over the railing (not shown) by means of a crane on a work vessel (not shown). A bird net (not shown) covering the fish pen is moved aside somewhat so that the vessel 1 can be lifted unobstructedly over the railing and put down on the inside of the railing and buoyancy body. The height of the vessel 1 is lower than the railing, so that the bird net may be reattached after the lifting operation. The low height of the vessel 1 allows the vessel 1 to be moved unobstructedly sideways around the internal circumference of the entire fish pen.

When the longitudinal axis 68 of the cleaning device 6 is oriented horizontally, it is the most advantageous for the vessel 1 to be stationary while the cleaning device 6 is moved downwards and upwards along the seine wall until this is clean in that portion. Then the vessel 1 is moved sideways to the next position. When the longitudinal axis 68 of the cleaning device 6 is oriented vertically, it is the most advantageous for the vessel 1 to move sideways along the buoyancy body while, at the same time, the cleaning is going on. The cleaning device 6 is then kept at a constant depth. This is advantageous as there is more fouling on the upper portion of a submerged net than on the deeper portions of the net.

It should be noted that all the above-mentioned embodiments illustrate the invention, but do not limit it, and persons skilled in the art may construct many alternative embodiments without departing from the scope of the attached claims. In the claims, reference numbers in parentheses are not to be regarded as restrictive.

The use of the verb "to comprise" and its different forms does not exclude the presence of elements or steps that are not mentioned in the claims. The indefinite article "a" or "an" before an element does not exclude the presence of several such elements.

The fact that some features are indicated in mutually different dependent claims does not indicate that a combination of these features cannot be used with advantage.