Background of the Invention It is known to construct floating structures for various applications such as floating platforms for off-shore drilling rigs; pontoon bridges; and aquaculture or fish pens. By and large, such structures are made from metallic pipes, beams and girders which are welded together.

Buoyancy is often provided by use of tubular structural elements which are sealed to form air chambers.

Alternately, the tubular elements can be filled with buoyant material such as polystyrene foam.

Usually the construction of these structures requires the use of welding machines and other power tools such as grinders; lifting and handling equipment such as cranes, pullies and forklift trucks; and skilled tradespeople. As a result, the construction of these structures is capital intensive. It further follows because of the construction requirements these structures are usually, though not always, constructed in factories which are some distance away from the place where the structure is to be used.

Therefore, the structure would need to be transported sometimes considerable distances to the place of use.

Depending on the size of the structure, it may be made in one or more prefabricated units and then fully assembled on site again using welders, and skilled tradespeople etc.

Once fully constructed, the structure is floated out to the

intended place of use.

Such structures are permanent in the respect that they cannot be easily disassembled or otherwise modified.

Further, as these structures are rigid they suffer from cyclic wave action and may fatigue.

It is also known to make aquaculture/fish pens by forming a buoyant ring or structure from a plastic tube and suspending a net from the ring. The ends of the plastic tube may be connected by welding and/or the use of mechanical fasteners. Various couplings may also be attached to the ring in order to allow the ring to be tethered to a mooring.

In order for the tube to have sufficient mechanical strength and buoyancy it must have a predetermined minimum diameter. This minimum diameter in turn limits the diameter of the ring which can be formed from the tube.

Unfortunately, one cannot simply reduce the diameter of the tube itself to form a smaller diameter ring as a minimum diameter tube is required in order to provide sufficient buoyancy and mechanical strength.

In addition, these tube ring type aquaculture/fish pens do not conveniently lend themselves to nesting or interconnection with other like aquaculture/fish pens.

Fish pens made from plastics tube can of course be made in shapes other than rings by simply cutting the tubes and welding them together. These pens also suffer from not being demountable nor easily connectable to adjacent like pens.

Summary of the Invention The present invention was developed with a view to

providing a demountable floating structure and an aquaculture pen incorporating the same which are particularly easy to assemble without the need of specialised technicians or tradespeople and can be easily disassembled as required.

According to one aspect of the present invention there is provided a demountable floating structure including a plurality of elongate pontoons and a plurality of connection means associated with said pontoons for detachably connecting adjacent ends of adjacent pontoons together.

Preferably each connection means includes a connection element and at least one detachable mechanical fastener for detachably connecting the connection element to the end of an adjacent pontoon.

Preferably, each connection element is provided with first and second connectors for detachably connecting to different ones of the ends of adjacent pontoons.

Preferably each connection element is formed separately of the pontoons. Although in an alternate embodiment respective connection elements can be formed integrally at one or each end of the pontoons.

Preferably the first and second connectors are arranged to allow relative movement between the connection element and the end of a pontoon connected thereto.

Preferably the first and second connectors comprise first and second pairs of lugs respectively, the lugs in each pair spaced apart to receive the end of an adjacent pontoon, and wherein a mechanical fastener passes through the lugs of that pair and the end of a pontoon received between those lugs, and is secured to those lugs.

Preferably the connection means further includes a plurality of tapered bushes, each bush partly disposable in one of the lugs and partly disposable in a tapered hole formed in a side of the end of each pontoon received between that one lug and the other lug which forms a pair with the one lug, and wherein the one mechanical fastener passes through the bushes disposed in a pair of lugs and retains the bushes therein.

Preferably said structure further includes coupling means for allowing coupling of adjacent similar structures.

Preferably the coupling means is configured to allow at least one degree of freedom of movement between adjacent coupled structures.

Preferably the at least one degree of freedom comprise a pivoting motion in opposite directions about a substantially horizontal axis extending between the adjacent coupled structures; and, a tilting and/or vertical motion in a vertical plane containing said substantially horizontal axis.

Preferably the coupling means includes a third pair of spaced apart lugs and a tongue, each lug of the third pair adapted to receive and have secured thereto a mechanical fastener, and the tongue provided with an upright slot, wherein the tongue of the coupling means of one structure is located between the lugs of the third pair of lugs of an adjacent structure and the mechanical fastener is passed through the slot and secured to the lugs of the third pair of lugs, the horizontal axis being coincident with the length of the mechanical fastener and the vertical plane containing the slot.

Preferably the coupling means is provided on each connection element.

However, in an alternate embodiment, the coupling means is provided directly on each pontoon. In this alternate embodiment one connection element is integral formed at each end of each pontoon.

In one embodiment the demountable floating structure further includes a platform or deck detachably coupled to a side of the pontoons above the level of water in which the structure floats when disposed in a body of that water.

In another embodiment the floating structure further includes one or more enclosures supported by the pontoons, said enclosures defining one or more confinement regions for sustaining and/or growing marine animals so that, in use, the floating structure acts as an aquaculture pen.

Preferably each pontoon is formed with a substantially planar or slightly curved upper surface which can act as a walkway around the structure.

According to another aspect of the present invention there is provided an aquaculture pen for the confinement of marine animals, the pen including: a plurality of elongate pontoons arranged end to end with adjacent ends of adjacent pontoons being detachably connected together in a planar manner by connection means; and one or more enclosures supported by the connected pontoons defining one or more confinement regions for sustaining and/or growing their in marine animals.

Preferably the enclosure is in the form of a net which is supported about the periphery of the pontoons.

In alternate embodiment, the enclosure is in the form of one or more racks for holding molluscs.

Preferably the pen further includes means for supporting the net from a level above the surface of water in which the pen floats when disposed in a body of that water.

Preferably the means for supporting the net includes a plurality of upright posts, respective posts detachably connected to either each pontoon or each connection means; and, a cross member extending between adjacent upright posts from which an upper peripheral edge of the net can be supported.

Preferably the level of each cross member can be adjusted to allow adjustment of the height of the net above the water surface.

In one embodiment the cross member comprises a rigid rail supported at each end by adjacent upright posts. However, in an alternate embodiment, the cross member may be in the form of a rope or tether supported at each of the upright posts.

Brief Description of the Drawings The embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a upper perspective view of a demountable floating structure and a fish pen incorporating same in accordance with a first embodiment of the present invention; Figure 2 is a view of transverse cross section 2-2 through a pontoon used in the demountable floating structure/aquaculture pen shown in Figure 1;

Figure 3 is an upper perspective view illustrating the coupling between two adjacent structures/pens; Figure 4 is a cross sectional view of a coupling element and a support post used in the structure/aquaculture pen shown in Figure 1; Figure 5 is a perspective view of a hook member used to support a net on the structure/pen shown in Figure 1; Figure 6 is a view of section 6-6 shown in Figure 5; Figure 7 is an enlarged exploded view of the connection between pontoons and connection elements used in the structure and pen shown in Figure 1; Figure 8 is a view of section 8-8 shown in Figure 3; Figure 9 is a perspective view of an end of a pontoon; Figure 10 is a upper perspective view of a second embodiment of the demountable floating structure and aquaculture pen incorporating same; Figure 11 is a close up view of an end of a pontoon used in the second embodiment shown in Figure 10; Figure 12 is a close up view showing the connection between two adjacent pontoon members of the second embodiment shown in Figure 10;

Figure 13 is a perspective view of a third embodiment of the mountable floating structure; Figure 14 is a perspective view of a fourth embodiment of the demountable floating structure; Figure 15 is a close up view of detail A shown in Figure 14; and Figure 16 is a perspective view of a fifth embodiment of the demountable floating structure.

Detailed Description of the Preferred Embodiments Referring to the accompanying drawings and in particular, Figures 1-4, a demountable floating structure 10 includes a plurality of elongate pontoons 12 and a plurality of connection means 14 associated with each pontoon 12 for detachable connecting adjacent ends of adjacent pontoons together. The elongate pontoons 12 are shown as being straight although they can be curved or bent. In this embodiment, each connection means 14 is in the form of a connection element 16 and at least one mechanical fastener 18 such as a bolt or pin for detachably connecting the connection elements 16 to the ends of adjacent pontoons 12.

As shown in Figures 1, 2, 7 and 9 each pontoon 12 is in the form of a substantially sealed elongate rectangular sectioned tube which is sealed. The pontoon 12 can be provided with several dividing walls 20 as shown in Figure 2, to define several separate substantially sealed buoyant chambers 22. Upper surface 24 of the pontoon 12 is slightly convexly curved to form shallow gutters 26 to provide for the collection and drainage of water, the water being drained at opposite ends of the pontoons 12. The surface 24 forms a walkway around the structure 10. To

allow for thermal expansion of the air within the pontoon 12 and chambers 22, a pressure relieve valve (not shown) is placed at the highest point of the curved upper surface 24. Additional relieve valves may be provided in walls 20.

The relieve valves assist in preventing fracturing of the pontoons 12 due to thermal expansion of the air contained there within. Although it is to be understood that each pontoon 12 may be formed as a single substantially sealed buoyant chamber without the separate chambers 22 and dividing walls 20. Indeed for easy of manufacture and to reduce costs it would be preferable that the pontoons 12 are formed in this way.

The connection elements 16 are separate distinct units from the pontoons 12. Each connection element 16 has first and second connectors in the form of pairs of spaced lugs 28 and 30 (see most clearly in Figures 3 and 7). The ends of pontoons 12 to be connected together to form the structure 10 are received between the lugs of prospective pairs 28 and 30. A mechanical fastener 18 couples the end of a pontoon 12 to one of the pairs of lugs 28 or 30.

Respective tapered bushes 35 are located in adjacent pairs of holes 31 and 33 (the holes 31 and 33 being positioned so that they can be brought into mutual alignment). Each bush 35 is provided with contiguous first and second lengths 37 and 39 which have tapers complementary to that of holes 33 and 31 respectively (see Figure 8). Thus the first length 37 fits in hole 33 and the second length 39 fits in hole 31. The pin/bolt 18 is passed through the holes and bushes 31, 33, 35 and a washer 39 and nut 41 used to secure the pin/bolt 18 in the lugs 28. Because of the taper in the holes 31 and 33, and the taper of bushes 35 the pin/bolt 18 locks the bushes in place thus detachably connecting the pontoon 12 to lugs 28. Further, the tapered bushes 35 simplify assembly as they pull adjacent components into alignment when the bushes 35 are drawn together by the

bolt/pin 18. A similar arrangement is used to detachably connect the end of an adjacent pontoon 12 to lugs 30 of the same connection element 16. The bushes 35 and pin/bolts 18 allow relative pivotal motion of the element 16 and connected pontoon 12 about the length of pin/bolt 18.

As seen in Figure 9 the end of each pontoon 12 is formed with an inverted U-shaped structure 25 having opposite legs 27A and 27B and a connecting upper cross bar 29. Leg 27A is flush with one side surface 32 of the pontoon 12 but leg 27B is set inwardly of the other side surface 34 of the pontoon 12, by a distance approximately equal to the width of one of the lugs 28, 30. This ensures, when structure 10 forms a closed shape as shown in Figure 1, and the sides 34 are on the inside of that shape, that the inner peripheral surface about the pontoons 12 and elements 16 are substantially continuous. This is of benefit when a net is suspended on the inside of the shape as it eliminates edges on which the net may catch.

Each leg 27A, 27B is provided with a through hole 31 which is tapered so as to reduce in diameter in a direction toward each other. Similarly each lug 28 is provided with a through hole 33 which is tapered in the same direction as holes 31, but the degree or slope of taper is less than for holes 31.

The lugs 28 and 30 are angularly offset about the side of the connection element 16 by 1200. Accordingly, as shown in Figure 1, when the structure 10 is constructed using six of these elements 16 and the pontoons 12 arranged to form a closed shape, the shape will be that of a hexagon. It will be appreciated that the actual shape of the structure 10 can be varied by use of elements 16 in which the connecting lugs 28 and 30 are disposed at different angles to each other. For example, as shown in Figures 13 and 14, a structure can be formed in a square shape if the pairs of

lugs 28 and 30 are offset by 900 about the periphery of the connection elements 16.

Coupling means are also provided to allow two or more adjacent structures 10 to be coupled together. As shown in Figures 1, 3 and 7, the coupling means is in the form of a third pair of lugs 40 and a tongue 42. The lugs 40 and tongue 42 are formed on a side of the connection elements 16. Thus lugs 40 are provided with holes for receiving a mechanical fastener such as bolt 44. The tongue 42 is provided with an elongate slot 46 which extends in the vertical direction. In order to connect two adjacent structures 10 together the tongue 42 of the connection 16 of one structure 10 is located between the lugs 40 of one connector 16 of another structure 10 and the bolt 44 is then passed through the slot 46 and secured to the lugs 44 typically by use of a nut. (In an alternate arrangement the bolt 44 can be replaced with a tube, with washers and split pins replacing the nuts). This is repeated at the opposite end of the adjacent pontoons of the adjacent structures 10, as shown in Figure 1.

It will be appreciated that this coupling between the adjacent structure 10 allows for at least one degree of freedom. One degree of freedom is a pivoting motion in opposite directions between adjacent structures 10 along a substantially horizontal axis AA (shown in Figure 1) which passes through the length of the bolts 44. Another degree of freedom is a tilting and/or vertical motion in a vertical plane containing the axis AA and moreover the slots 46.

The demountable floating structure 10 can be easily converted into an aquaculture pen by providing various types of enclosure means which are supported by the structure 10.

As shown in Figure 1, an aquaculture pen 48 comprises the demountable floating structure 10 together with a net 50 supported thereby. The net 50 extends about the inner periphery of the structure 10 and supported by support means at a level above the surface of water in which the pen 48 floats. The supporting means is in the form of a rail structure 52 comprising a plurality of upright posts 54 which are detachably coupled to each connection element 16 and cross members in the form of rails 56 which are supported at each end by adjacent posts 54.

As depicted in Figure 4, each post 54 is provided with a tapered lower end 58 which is received within a complimentary shaped recess 60 formed in the connection element 16. The bottom of the recess 60 is provided with a horizontal wall 62 which is recessed into the element 16.

The end 58 is detachably connected by a mechanical fastener in the form of a bolt 64 to the wall 62.

A T piece 64 (see Figures 1 and 3) is attached to the upper end of each post 54 for receiving the ends of the rails 56.

Each T piece 64 is formed as an integral moulded piece having a plurality of short tubular lengths which fit over the top of a rail 54 and receives ends of the rails 56.

An upper peripheral edge 66 (Figure 1) of the net 50 is fastened at regular intervals to the rail 56 by ties 68.

The ties may be in the form of short lengths of rope or off-the-shelve plastic rib lock ties. When the pen 48 is placed in a body of water, the pontoons 12 float on the water and the inside of the net 50 defines a confinement area in which marine animals can be sustained or grown.

Having the upper peripheral edge 66 of the net disposed above the water level reduces the likelihood of the marine animals contained therein jumping out and other, possibly predatory, marine animals outside the net from jumping in.

Also, a bird net (not shown) can be hung above the

enclosure off the rails 56.

In a further variation (not shown) the T pieces 64 can be attached to the post 54 in a manner so that their height can be varied. For example this can most easily be done by providing the post 54 with a series of holes to which the T pieces can be coupled. This provides a way for adjusting the height of the net above the water level as well as assisting in retrieving in a net.

Instead of using ties 68 to attach the net to the posts 28, hooks 70 can be provided as shown in Figures 5 and 6. The hooks 70 are used to support a cord 72 which extends around the peripheral edge 66 of the net 50. Each hook 70 is provided with a first arcuate portion 74 which extends about and sits on an upper part of the rail 56. Depending from the surface of the first portion 74 which sits on the rail 56 is a clip 76 which is adapted to pass through a hole 78 formed in the top of the rail 56. The clip 76 includes a barb 79 which engages an inner surface of the rail 56 to positively lock the hook 70 in place. Formed continuously with the first portion 74 is a second portion 80 which is upwardly curved to form a deep pocket 82 within which the cord 72 sits.

The manner of forming the demountable detachable connection between adjacent pontoons 12 in the embodiment shown in Figures 1-9 allows one degree of freedom in opposite directions of the pontoons relative to the connection elements 16. Additionally as hereinbefore described the manner of coupling between adjacent structures 10 or fish pens 48 provides several degrees of freedom therebetween.

This allows movement of one structure 10 or pen 48 relative to an adjacent coupled structure 10 or pen 48 in response to wave motion.

A second embodiment of the floating support structure designated 10' is shown in Figures 10-12. In these figures, features corresponding to those of the first embodiment are indicated with the same reference numbers but with the addition of the prime symbol.

The structure 10' differs from the structure 10 mainly by the formation of the connection elements 16' integrally with opposite ends of the pontoons 12'. The connection elements 16' comprise a connection flange 82 which extends half way around each end of the pontoon 12' and a mating surface 84 which extends about the other half of each end of the pontoons 12'. The relative position of the flange 82 and mating surface 84 is reversed on opposite ends of each pontoon 12' so that the flange 82 at the end of one pontoon 12' will overlie the mating surface 84 at an adjacent end of an adjacent pontoon 12' (see Figure 12).

A series of holes 88 are formed along the flange 82.

Likewise a series of holes 90 are formed along the mating surface 84. When the flange 82 of one pontoon 12 overlies the mating surface 84 of an adjacent pontoon 12' the respective holes 88 and 90 are in registration. This allows the use of mechanical fasteners such as bolts 92 which pass through the registered holes 88 and 90 for detachably connecting adjacent pontoons 12' together.

It will be noted that in contrast with the first embodiment of the structure 10, in the structure 10' there is no degree of freedom between adjacent pontoons 12'.

Accordingly in this embodiment the pontoons 12' when connected form a rigid, but nonetheless demountable structure.

The connection elements 16' are angularly offset with respect to the central axis of the pontoons 12' to form an internal angle of 1200 so that when six identical pontoons

12' are connected together they form a hexagonal structure similar to that shown in the first embodiment.

A further significant difference between the first embodiment 10 and the second embodiment 10' is that the lugs 40' and tongue 42' which form the coupling means for adjacent structures 10' (or corresponding aquaculture pens) are formed integrally with the pontoons 12'. In the first embodiment it will be remembered that lugs 40 and the tongue 42 are formed on the connection elements 16.

A further difference lies in the upper wall 24' of the pontoons 12' being planar rather than curved as in the first embodiment. Elongate ribs 94 are formed along opposite sides of the top wall 24' to act as a safety guard when walking along the tops of the pontoons 12'. The ribs 94 are approximately one quarter the length of the pontoons 12' and are provided with small gaps therebetween to allow for the drainage of water.

The posts 54' are attachably coupled in recesses 60' of the pontoons 12' in a similar manner to that shown in the first embodiment. However, in the present embodiment, the rails 56 of the first embodiment are replaced with a rope or tether 95 which passes through a hole 96 formed in each of the posts 54'. A number of holes 96 can be provided along the length of each post 54' to allow the rope or tether 95 to be suspended from different heights. The rope or tether 95 can be either of a continuous length or made from shorter sections. When a aquaculture pen is formed using the support structure 10' the peripheral edge of the net can be tied or otherwise suspended from the rope or tether 95.

Figure 13 shows a further embodiment 10'' of the demountable floating structure. This embodiment comprises four elongate pontoons 12' ' which are of identical

structure to the pontoons 12 of the first embodiment and four separate connection elements 16' ' which are similar, although not identical, to the connection elements 16 of the first embodiment. The connection elements 16'' are formed with the lugs 28'' and 30'' offset by 900 to each other about the periphery of the connection elements 16'' so that the structure 10'' is in the form of a square. The structure 10'' includes a platform or deck 98 which overlies the area defined by the pontoons 12'' . The deck 98 is detachably attached via plugs 100 which are inserted into the recesses 60'' formed on each of the connection elements 16''. The recesses 60'' would otherwise be used for receiving post similar to posts 54 and 54'.

The elements 16'' include lugs 40'' and a tongue 42'' to allow for the coupling with other structures of aquaculture pens in accordance with embodiments of this invention.

Accordingly the structure 10'' can be used to provide a storage area for equipment which may be employed when embodiments of the support structure/aquaculture pen are in use. Indeed, the structure 10'' can also be used to support a shed or other building.

Yet a further embodiment of the present invention is shown in Figure 13. This figure shows an aquaculture pen 10''' for harvesting molluscs such as oysters. The structure 10''' is similar to structure 10't as shown in Figure 12 with the exception that the deck 98 is now replaced with a grid network 102 from which oyster racks 104 can be suspended by ropes or chains or the like. The pontoons 12''' and the connection elements 16''' are identical to the same items in the second embodiment 10''. Post 54''' are detachably connected to respective connection elements 16''' in the same manner as described with the first embodiment. A plurality of cross members 106 extend across and are detachably connected at their ends two opposite lower rails 16'''. The cross members 106 are detachably

connected to the rails 56' '' by use of conventional scaffolding type connectors 108.

A fifth embodiment of the present invention is shown in Figure 16. This figure shows a structure 10'''' which is in effect a hybrid between the embodiment shown in Figures 1-9 and the embodiment shown in Figures 10-12. The structure 10'''' is characterised by pontoons 12'''t which have an integral connection element 16'''' at one end which is of a form substantially similar to element 16 of the first embodiment 10 with the opposite end of each pontoon 12t''' formed with an inverted U shaped structure identical to structure 25 shown in Figures 9 and 7 to allow connection with the connection element 16"" of an adjacent pontoon 12'''' in a manner identical to that described with reference to Figures 7. The elements 16 have only one pair of lugs 30'''' for connecting with the end of an adjacent pontoon 12''''. Therefore, each connection element 16'''' provides only one moveable or flexible coupling with an adjacent pontoon 12''''. In the first embodiment shown in Figures 1-9, each coupling element 16 provides two moveable or flexible couplings between adjacent pontoons. Whereas in the embodiment shown in Figures 10-12, the connection elements 16' do not provide for any flexible or moveable connection between adjacent pontoons 12' of the same structure 10' . Lugs 40'''' and tongue 42'''' are provided on elements 16'''' to allow for coupling to an adjacent structure 10', 10'', 10''', or 10''''.

From the above description it would be readily apparent that the embodiments of the present invention enjoy numerous advantages and benefits over the prior art.

Significantly, the assembly of the structures is achieved by use of detachable mechanical fasteners only rather than the use of permanent connection methods and techniques such as welding and braising etc. It follows from this that the

structures can be put together without the need for skilled tradespeople. Typically, the only tools that would be required to assemble the structures are a hammer, screw driver and spanner. In addition, the structures 10 can be supplied in a kit form and therefore easily transported in a disassembled state and then simply assembled adjacent the body of water into which they are to be deployed. The structures 10 also easily facilitate the coupling to like structures so that the capacity of the structure can be increased by coupling of fresh structures. The structures coupled can be of different shapes and sizes. If it is desired to move this structure to a different body of water, it can be easily disassembled and transported to that other body.

Now that embodiments of the present invention have been described in detail it would be apparent to those skilled in the relevant arts that numerous modifications and variations may be made without departing from the basic inventive concepts. For example, the connecting elements 16 can be made to a particular shape and configuration to enable the structure 10 or aquaculture pen 48 to be made of any desired shape. Additionally, any type of conventional enclosure can be supported on the structure 10 to form an aquaculture pen. Thus, in addition to supporting a net 50 or oyster racks 104, other types of enclosures such as cages can be supported. When the structure 10 is used as an aquaculture pen 48, predator netting can also be provided on the outer periphery of the structure to further assist in protecting the marine life held within the aquaculture pen. The pontoons 12 and connection elements 16 can be made from any marine grade material but typically would be made from a synthetic plastics material such as polyethylene. The posts 54, rails 56 and T pieces 64 would typically be made from aluminium or stainless steel although other materials suited to the application can be used such as plastics including polyethylene. Typically

the mechanical fasteners 18, 44 would be in the form of elongate stainless steel pins which are threaded at both ends in order to receive nuts. However, any other type of releasable mechanical fastener can be employed. In yet a further variation the elongate pontoons 12 can be bent or curved so that the structure 10 takes a circular or elliptical form. This will of course also require modification to the configuration (ie shape only) of the connection elements 16. Such variations in the shape and configuration of the pontoons 12 and connection elements 16 are immaterial to the working and function of the invention and do not change the essential character of the invention.

All such modifications and variations together with those which would be obvious to a person of ordinary skill in the art, are deemed to be within the scope of the present invention the nature of which is to be determined from the aforegoing description and the appended claims.