GB2227634A

GB2227634A - Fish farm structure

Info

Publication number: GB2227634A
Application number: GB8902518A
Authority: GB
Inventors: William Lithgow
Original assignee: LITHGOWS Ltd
Current assignee: LITHGOWS Ltd
Priority date: 1989-02-04
Filing date: 1989-02-04
Publication date: 1990-08-08
Anticipated expiration: 2009-02-04
Also published as: GB2227634B; NO900540L; GB8902518D0; NO900540D0; NO173971C; NO173971B

Abstract

A fish cage 1 is formed from an upper square member 2 (above the water line) and a lower buoyant square member of smaller size than the first member 2 and is connected thereto by an upstanding leg 4 at each corresponding corner. Two rows of opposed spaced pairs of fish cages 1 can to be used to form a composite fish farm structure. A central spine of flexibly connected pontoons are provided between the opposed fish cages 1 and are hinged thereto to allow relative movement. A further pontoon acting as a bow turns into the prevailing current or wind to protect the remaining structure. <IMAGE>

Description

FISH FARM STRUCTURES FISH . ~ FARM STRUCTURES The present invention relates to novel fish farm structures, particularly but not exclusively to fish farms for offshore use in rough waters.

Typical known fish farm structures are made from, for example, floating steel pontoons which are linked together to form an enclosed space and have a net hung from them to contain the fish. Whilst being suitable for use in sheltered waters, these structures are not particularly suited to use in rough waters as they tend not to be flexible enough to ride out the waves.

Attempts have been made to make these known structures more flexible, and thus capable of riding the waves, by making the steel pontoons from smaller pontoons articulated to each other, by suitable joints. However these attempts have not been entirely successful in rough waters.

Accordingly the present invention provides a fish farm structure having a cage frame formed from a buoyant lower member joined to an upper member, whereby in use said buoyant lower member is submerged and said upper member is clear of the water surface.

Preferably the buoyant lower member is square, although other shapes including for example, circles and rectangles may be employed, and is smaller than the upper member which is also preferably square although it too may be any other suitable shape. Thus preferably a cage frame of the present invention has a shape resembling an inverted pyramid which makes it very rigid. It will be appreciated that in other embodiments the upper member may be smaller than the lower member.

Suitably the lower and upper members are connected by for example legs at each corner of the upper and lower members, with additional connecting legs at other locations if considered necessary. These legs act to provide stability to the cage frame when placed in the water, the cross section of the legs affecting the stability provided.

Cage frames according to the present invention can be made from any suitable materials, such as metals, for example steel, or plastics, or wood.

Preferably an upper surface of the upper member is so constructed as to provide an area to allow people to walk around and work on the cage frame.

The position of the cage frame in the water can be raised or lowered by altering the buoyancy of the lower member.

This can be achieved for example having water ballast in the lower member and by adding or removing buoyancy to it.

Nets can be hung from the cage frames to contain fish or aquatic creatures. Cage frames accoiring to the present invention may also be joined togethei, by articulated joints, to form a large structure and then moored in the water.

When thus joined together, the cage frames provide an articulated structure which can move with the waves, the individual cage frames being rigid and riding the waves.

An embodiment of the present invention will now be described by way of example only and with reference to the accompanying drawings in which Figure 1 is a side view of a cage frame of the present invention, Figure 2 is a plan view of a cage frame of the present invention and Figure 3 is a plan view of a number of cage frames of the present invention joined together to form one unit.

Referring now to Figures 1 and 2 these show a cage frame 1, having an upper member 2 joined to a lower buoyant member 3, which is below the water. Legs 4 join the upper 2 and lower 3 members together. The cross section of the legs 4 affect the stability of the cage frame 1 in the water. A net, (not shown) can be hung from the cage frame 1. Walkways and other fittings (not shown) may be placed on or built into the upper member 2.

Figure 2 shows clearly that the upper frame 2 is larger than the lower frame 3.

Figure 3 shows a plan view of a composite fish farm structure comprising a number of cage frames 1 linked together by hinges 31 and to pontoons 32 which form a central spine. The hinges 31, made in this embodiment from hardened steel pins in oversize holes, allow the cage frames 1 to move relative to each other and to the pontoons 32.

Pre-loaded rubber buffers 33 serve to prevent the cage frames 1 from hitting each other. A large pontoon 34 serves to provide accomodation for equipment personnel etcetera and a further pontoon 35 provides additional accomodation and also acts as a "bow" for the fish farm structure. In use the "bow" 35 will tend to orientate so that it beds into the prevailing current, tide or wind thus helping to protect the rest of the fish farm structure from damage. The "bow" 35 is moored by a mooring means 36, in this case an anchor. The bow 35 has two sponsons 37,38 which are hinged 39,40 to the bow 35. These sponsons 37, 38 can be deployed outwards to help provide protection for the cage frames 1.

Claims

1. A fish farm structure having a cage frame formed from a buoyant lower member joined to an upper member, whereby in use said buoyant lower member is submerged and said upper member is clear of the water surface.

2. A fish farm structure as claimed in claim 1 wherein the buoyant lower member is smaller in size than the upper member.

3. A fish farm structure as claimed in claims 1 or 2 wherein at least one of the upper or buoyant lower members and preferably both are square.

4. A fish farm structure as claimed in any one of the preceding claims wherein the upper member and lower buoyant member are connected by spaced legs of suitable cross section to provide adequate stability.

5. A composite fish farm structure comprising a plurality of fish farm structures as claimed in any one of the preceding claims which are flexibly joined together to ride the waves.

6. A composite fish farm structure as claimed in claim 5 comprising at least two rows of opposed pairs of said fish farm structure, a central spine of flexibly connected pontoon members separating said opposed pairs, each fish farm structure being flexibly joined or hinged to the adjacent pontoon member to allow relative movement thereto and to the other fish farm structures.

7. A composite fish farm structure as claimed in claims 5 or 6 wherein a further pontoon is provided at one end thereof which is adapted to act as a bow and in use orientates so as to bend into the prevailing current, tide or wind thus helping to protect the rest of the composite fish farm structure from damage.

8. A composite fish farm structure as claimed in claim 7 wherein at least two sponsons are further provided hinged to and extending laterally from the bow pontoon to help provide further protection to the fish farm structures.

9. A composite fish farm structure as claimed in claims 7 or 8 wherein a further pontoon is provided at the opposite end thereof relative to the bow pontoon.

10. A fish farm structure substantially as described with reference to Figs. 1 and 2.

11. A composite fish farm structure substantially as described with reference to Fig. 3.