AU2013203731B2

AU2013203731B2 - A submersible structure

Info

Publication number: AU2013203731B2
Application number: AU2013203731A
Authority: AU
Inventors: John Brent Hutchinson
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-05-22
Filing date: 2013-04-11
Publication date: 2015-05-21
Anticipated expiration: 2033-04-11

Abstract

A submersible structure for forming an aquatic habitat on a substrate comprising a first body portion for S providing shelter and attachment sites for aquatic life and a second body portion for supporting the first body portion on the substrate, wherein the first body portion is generally radially symmetrical and comprises a plurality of plates that are angled relative to each other 10 and angled relative to the second body portion to redirect fluid flowing across the plurality of plates, the general radial symmetry of the first body portion allowing energy from fluid flowing across the submersible structure from at least three directions to be dissipated by about a 15 similar amount. 4217694_1 (GHMaltars) PO9G96.AU.1 C))

Description

- 1 A SUBMERSIBLE STRUCTURE FIELD OF THE INVENTION 5 The present invention relates to a structure for use in an aquatic environment. BACKGROUND OF THE INVENTION 10 Underwater structures such as tyres and scuttled ships have been used as habitats for aquatic life. It is hoped that these structures maintain the aquatic environment of a given area, such as lakes, seas, oceans and the like to avoid the loss in biodiversity and to maintain the 15 wellbeing of aquatic species such as fish and seaweed. A collection of such structures typically forms an aquatic reef for aquatic species to reside in. One can appreciate that scuttling a ship is time intensive 20 and costly due to the size and weight of the ship. There is also a risk of introducing toxic materials into the aquatic environment during the scuttling process. Additionally, there are limited areas that are large and have deep enough water to accommodate such ships which are 25 often decommissioned battleships. In non-deep water aquatic areas such as ponds, lakes, rivers and the like, it can be appreciated that scuttling ships is not a viable option to provide an artificial 30 habitat for aquatic life to populate. Additionally, corrosion of the ships over time may adversely affect aquatic life by releasing toxins into the environment which may kill or injure the aquatic life. The size of the ship also reduces water circulation through the ship which 35 in turn decreases the oxygen content within the ship. When using tyres as artificial habitats, one has to bear 6385658_1 (GHMatters) P89896.AU.1 PCABRAL - 2 in mind that the composition of a tyre may affect its buoyancy. As a consequence, tyres often have to be bundled together to provide sufficient weight to prevent them from being carried away by water currents. However, degradation 5 of these bindings may release individual tyres that may impact and damage immobile aquatic life such as coral. The tyres may also affect the aquatic environment if the tyres are not treated properly before being used as an 10 aquatic habitat. Leaching of toxins from the tyres over time or during the degradation process of the tyres may have a profoundly negative effect on the environment. Accordingly, it is desirable to provide a non-toxic 15 submersible structure adapted to improve fluid circulation through the structure and that can be arranged to form an artificial reef. SUMMARY OF THE INVENTION 20 In one form, there is provided a submersible structure for forming an aquatic habitat on a substrate comprising a first body portion for providing shelter and attachment sites for aquatic life and a second body portion being a 25 plate for supporting the first body portion on the substrate, the second body portion for resting on the substrate to shield the substrate beneath the second body portion from erosion, the first body portion being generally radially symmetrical and comprising a plurality 30 of plates that are angled relative to each other and angled relative to the plate of the second body portion to form a hollow structure for aquatic life to reside in, the first body portion including at least one opening for the aquatic life to enter the hollow structure and/or for 35 fluid circulation within the hollow structure, wherein an opening between the first and second body portions reduces accumulation of debris within the submersible structure. 6385658_1 (GHMatters) P89896.AU.1 PCABRAL - 3 In one form, there is provided a method for creating an artificial reef on a substrate comprising a plurality of submersible structures, each submersible structure comprising a first body portion for providing shelter and 5 attachment sites for aquatic life and a second body portion for supporting the first body portion on the substrate, wherein the first body portion is generally pyramidal in shape to redirect fluid flowing across the submersible structure, the generally pyramidal shape 10 allowing energy from fluid flowing across the submersible structure from at least three directions to be dissipated by about a similar amount, wherein the structures are arranged to abut each other to form an artificial reef in a compact arrangement that does not expose the substrate 15 to degradation. In one form, there is provided an artificial reef comprising a plurality of hollow submersible structures, each hollow submersible structure comprising a first body 20 portion for providing shelter and attachment sites for aquatic life and a second body portion for supporting the first body portion on a substrate, wherein the first body portion is generally pyramidal in shape to redirect fluid flowing across the submersible structure, the generally 25 pyramidal shape allows energy from fluid flowing across the submersible structure from at least three directions to be dissipated by about a similar amount, the generally pyramidal shape including a plurality of openings to allow aquatic life to enter the submersible structure and allow 30 circulation of fluid through the artificial reef, wherein the submersible structures abut each other to form a compact artificial reef in an arrangement that does not expose the substrate to degradation. 35 BRIEF DESCRIPTION In one form, the plates of the first body portion are 6385658_1 (GHMatters) P89896.AU.1 PCABRAL - 4 connectable to each other at an angle of less than 900. Preferably, the first body portion forms a generally pyramidal shape. 5 Connecting plates at an angle less than 900 forms at least three surfaces and three edges that allow fluid flow from at least three directions to strike the submersible structure and be redirected from the original direction of travel of the fluid. The energy from this redirection is 10 believed to be dissipated by about the same amount due to the number of substantially similar surfaces of the submersible structure that may be struck by the fluid. In one form, each plate of the first body portion is 15 connected to the second body portion at an angle of less than about 900. Preferably, the angle is from about 800 to about 600. More preferably, the angle is at or about 700. Reference to a generally pyramidal shape in the 20 specification includes a complete pyramidal shape formed by assembling three triangular plates on the second body portion, and a truncated pyramidal shape formed by assembling three triangular plates, each with the apex tip removed, on the second body portion. 25 Reference to the term "fluid" in this specification includes liquids such as for example fresh water, sea water, brackish water and mixtures thereof. 30 The angle of each plate relative to each other and relative to the second body portion may reduce soil erosion by redirecting fluid flow across the submersible structure. It is believed that fluid flowing onto a plate of the first body portion would be redirected from its 35 original direction of flow, thus reducing the energy of the fluid in its original direction of travel. This would reduce soil erosion by reducing the fluid energy available 6385658_1 (GHMatters) P89896.AU.1 PCABRAL - 5 to carry away soil on the bed of the body of fluid. It is believed that the reduction in energy of the fluid in its original direction of travel is increased by 5 adjusting the angle of each plate relative to each other. The angle of each plate relative to the second body portion may also be adjusted to redirect fluid from its original direction of travel. For example, a pyramidal structure has each plate angled at 600 relative to each 10 other and angled at an angle less than 900 relative to the second body portion. It is believed that the angle at which the plates of the first body portion are positioned improves turbulence in 15 the wake of the submersible structure when fluid flows across the submersible structure, wherein the generation of turbulent eddies reduces fluid energy from a direction of travel. 20 The angle of each plate relative to each other and relative to the second body portion may improve the stability of the submersible structure. It is believed that the angled structure provides a resultant downward force on the submersible structure to push the submersible 25 structure onto a substrate when fluid flows across the structure. The substrate can be any surface that the submersible structure rests on, such as for example the bed of a body 30 of fluid such as the sea, river, ocean, lake or the like. In one form, the first body portion includes at least one opening for fluid circulation. The at least one opening may also allow light to enter the first body portion. 35 Preferably, each plate of the first body portion includes at least one opening. More preferably, an apex portion of the first body portion includes an opening to redirect 6385658_1 (GHMatters) P89896.AU.1 PCABRAL - 6 fluid flowing through the first body portion. The opening at or around the apex of the first body portion provides an exit for fluid flowing through the 5 submersible structure. It is believed that fluid entering the openings on the plates would be redirected in a substantially vertical direction. This redirection of fluid distributes energy from the original direction of travel into other directions and consequently reduces soil 10 erosion by reducing the amount of energy available to carry soil away from the bed of the fluid body. This also improves aeration of the structure by creating a convoluted pathway for fluid to circulate the hollow interior of the submersible structure. 15 The opening further allows light to enter the interior of the submersible structure to allow aquatic plant life to photosynthesise. 20 A tether such as a rope, chain or the like may be connectable through the opening at or around the apex of the first body portion to allow the submersible structure to be lowered into the fluid in an upright position, removing the need to orientate the structure in the fluid. 25 In one form, the second body portion includes a connector such as a U-bolt to receive a hook attached to an end of the tether. This allows the submersible structure to be positioned in the fluid using a derrick or a crane, and 30 the tether can be removed from the connector after the submersible structure is manoeuvred into position. The form of the submersible structure may redirect fluid flow across the structure, wherein the fluid flows over 35 the first body portion and the fluid is deflected by the angled plates of the first body portion. 6385658_1 (GHMatters) P89896.AU.1 PCABRAL - 7 The form of the submersible structure may also redirect fluid flow through the structure, wherein fluid flows through the at least one opening on the plates of the first body portion and the fluid is redirected through the 5 opening at or around the apex of the first body portion. It is believed that the redirection of fluid flow across and through the structure reduces energy of the fluid from its original direction of travel. Consequently, the 10 reduction in energy may reduce soil erosion by reducing the amount of energy available to wash away soil from the bed of a body of fluid. The reduction in energy may also reduce waves buffeting water crafts moored in the vicinity of the submersible structure. 15 It is also believed that the redirection of fluid improves circulation of fluid through the structure. This aerates the interior of the submersible structure to improve the wellbeing of aquatic species populating the submersible 20 structure and may encourage additional aquatic species to reside in the submersible structure. The openings can also form fluid channels, when a plurality of submersible structures are arranged to abut 25 each other to form an artificial reef, such that openings located on the plates of the submersible structures align. This may allow aquatic life to swim through each submersible structure of the artificial reef and may also improve fluid circulation through the artificial reef. 30 In one form, the first body portion is textured to improve attachment of aquatic life, such as for example sea moss, mussels, barnacles and the like, onto the first body portion, particularly, the surface of the first body 35 portion. The first body portion may include textures, such as for example, grooves, scour lines, undulations, or the like. The textures may be of any shape and/or size, and 6385658_1 (GHMatters) P89896.AU.1 PCABRAL - 8 may be randomly arranged on the first body portion. Preferably, the textures are positioned horizontal to the second body portion to improve the likelihood of trapping 5 spats and/or spores that are carried by waves striking the first body portion. When waves strike the first body portion, particularly directly at a plate of the first body portion, the waves 10 are likely to travel in an upwardly direction to the first body portion. As such, having horizontal textures improves the likelihood of spats and/or spores carried by the waves to be caught by an upper surface of each horizontal texture. In contrast, there is an increased likelihood 15 that these spats and/or spores would travel through vertical textures and be washed away because of a lack of an upper surface to catch the spats and/or spores. In one form, the first body portion is connectable to the 20 second body portion to form a hollow structure for aquatic life to reside in. The second body portion functions as a rest or a foot to support the first body portion on a substrate. The second 25 body portion is connectable to the base of the first body portion to form a submersible structure with at least four faces forming a hollow interior. For example, a submersible structure comprising four faces may be a pyramidal structure wherein the first body portion defines 30 three faces and the second body portion defines a fourth face. Without a second body portion, anchoring a first body portion directly onto a substrate may damage the edges of 35 the first body portion as it digs into the substrate. In contrast, supporting the first body portion on the second body portion provides a flattened surface for the 6385658_1 (GHMatters) P89896.AU.1 PCABRAL - 9 submersible structure to rest on the substrate, reducing the likelihood that the edges on the base of the first body portion will be damaged when impacting the substrate. 5 In one form, each plate of the first body portion is connectable to each other by adhesion. Preferably, the first and the second body portions are connectable by adhesion. 10 Each plate may be connected by commercially available adhesives to allow rapid on-site assembly of the submersible structure. This allows individual components of the submersible structure to be transported in a compact and space efficient manner to the target location 15 and assembled on-site. In one form, the second body portion is a plate that allows the submersible structure to reduce soil erosion by resting on the bed of a body of fluid to shield the soil 20 on the substrate beneath the second body portion from being washed away. In one form, the first body portion includes an opening at or about its base to reduce accumulation of debris, such 25 as for example, shells, bones and the like in the submersible structure. The opening may be located at any position at or about its base. For example, the opening may be located at or about a bottom corner of a plate of the first body portion or the opening may be located at or 30 about the base of a plate of the first body portion. The opening may be an open channel. In this form, the opening is formed at the interface between the first and second body portions. Fluid may 35 enter the submersible structure through the opening and exit through any one of the other openings in the submersible structure to flush out debris collected in the 6385658_1 (GHMatters) P89896.AU.1 PCABRAL - 10 submersible structure. In one form, the second body portion includes one or more passages on its top surface to reduce accumulation of 5 debris, such as for example, shells, bones and the like in the submersible structure. The passage may be an open channel. In this form, the submersible structure includes one or 10 more passages located at or about the interface between the first and second body portions that is in fluid communication with the body of fluid. The passages may be located at any position at or about the interface between the first and second body portions. Fluid flow through the 15 passages may remove any debris within the submersible structure. In one form, the submersible structure is formed from non metallic material. Preferably, the submersible structure 20 is made from concrete. More preferably, the submersible structure is formed from a composite material comprising polymeric fibres and concrete. Most preferably, the composite material comprises polypropylene and concrete. 25 The polymeric fibres impart increased strength to the submersible structure and reduce the likelihood of the structure breaking up upon impact with another object such as an anchor. 30 In one form, a plurality of submersible structures are arranged to abut each other to form an artificial reef in a compact arrangement that does not expose the underlying substrate to reduce the likelihood of soil erosion. 35 The arrangement of submersible structures abutting each other forms a customisable artificial reef, wherein the size of the artificial reef can be controlled by adjusting 6385658_1 (GHMatters) P89896.AU.1 PCABRAL - 11 the number of submersible structures. The artificial reef also provides a habitat for aquatic life of different sizes, such as for example, large aquatic species such as turtles and stingrays that can reside in the space between 5 each submersible structure of the artificial reef, and small aquatic species such as fish and eels that can reside in the hollow interior of each submersible structure. 10 The artificial reef may be placed in any location in a body of fluid such as for example against piers under jetties. In one form, the arrangement of submersible structures 15 forms an artificial reef that allows redirection of fluid substantially in one direction. The location of an opening at or around the apex of each submersible structure allows fluid flowing across the 20 artificial reef through the openings located on each of the plates of the first body portion to be redirected through the opening at or around the apex of the structure. Not wanting to be bound by theory, it is believed that the collective redirection of fluid flow 25 through each structure is substantially in one direction, particularly in a substantially vertical direction, wherein fluid travelling across the submersible structure is directed substantially upwards through the opening located on or around the apex of the submersible 30 structure. It is believed that this fluid redirection improves aeration of the artificial reef and energy dissipation of fluid flowing across and through the reef. In one form, the artificial reef is arranged such that the 35 openings on the first body portions of the plurality of hollow submersible structures are aligned to form a plurality of fluid channels that improves fluid flow 6385658_1 (GHMatters) P89896.AU.1 PCABRAL - 12 through the artificial reef. Preferably, the fluid channels provide aquatic species improved access between the submersible structures of the artificial reef. 5 Alternatively, the artificial reef is arranged such that the openings on each plate of the first body portion are misaligned to disrupt fluid flow through the artificial reef. 10 This arrangement may improve dissipation of energy of fluid flowing through the artificial reef by preventing uninterrupted fluid flow through the artificial reef. BRIEF DESCRIPTION OF DRAWINGS 15 Figure 1 is a perspective view of a submersible structure according to one form of the present invention. Figure 2 is a side view of the submersible structure 20 without an opening in the second body portion according to another form of the present invention. Figure 3 is a top view of an artificial reef comprising a plurality of submersible structures arranged in an 25 abutting relationship to one another according to another form of the present invention. Figure 4 is a perspective view of two submersible structures having the openings on the plates of the 30 respective first body portions aligned with one another to form fluid channels. Figure 5 is cross-sectional view of Figure 1 across the A A axis. 35 DETAILED DESCRIPTION 6385658_1 (GHMatters) P89896.AU.1 PCABRAL - 13 One form of the submersible structure is marked as 10 in Figure 1. Submersible structure 10 comprising first body portion 12 5 for providing shelter and attachment sites for aquatic life and second body portion 14 for supporting first body portion 12 on substrate 15. The submersible structure is made of concrete reinforced with polypropylene fibres. However, in other forms of the structure, it can be made 10 with other non-metallic material. First body portion 12 is generally radially symmetrical and comprises three generally triangular plates that are angled at or about 600 relative to each other (angle a of 15 Figure 1) and at or about 700 relative to the second body portion (angle P of Figure 1) to form a generally pyramidal shape. The apex tip of each plate is removed such that, when 20 assembled, the three plates form a truncated pyramidal shape with opening 16 located at or around the apex of first body portion 12 about the central axis of the submersible structure. 25 The general pyramidal shape of submersible structure 10 functions to redirect fluid flowing across each of the plates of the first body portion 12 to reduce the energy of the fluid flowing in its original direction of travel. It is believed that the reduction in energy reduces the 30 available energy of the fluid to carry away soil from the substrate and thus, reduces soil erosion. Fluid flowing across submersible structure 10 can be deflected by the angle of the plates relative to each 35 other and relative to second body portion 14. It is believed this action dissipates energy of the fluid flow across submersible structure 10 by creating turbulence in 6385658_1 (GHMatters) P89896.AU.1 PCABRAL - 14 the wake of submersible structure 10 (Figure 5). Arrow Y in Figure 5 illustrates a path taken by the fluid which generates turbulence in the vicinity of the two other plates of the submersible structure. As a result, 5 turbulent eddies 17 reduce energy of the fluid flowing across the submersible structure. The reduction in fluid energy may also reduce the intensity of waves buffeting water craft moored in the 10 vicinity of the submersible structure. It is also believed the general radial symmetry of first body portion 12 allows energy from fluid flowing across submersible structure 10 from at least three directions to 15 be dissipated by about a similar amount. For example, first body portion 12 includes three plates that are joined together to form three edges 13. It is believed that fluid striking directly onto any one of 20 edges 13 will be deflected by about the same angle and a similar amount of energy will be dissipated during the redirection. Similarly, fluid striking directly onto the face of any one of the three plates will be deflected by about the same angle and result in a similar amount of 25 energy being dissipated. Advantageously, the angle of the plates of first body 12 may improve stability of the submersible structure by providing a resultant downward force to push the 30 submersible structure onto substrate 15 when fluid flows across submersible structure 10. Each plate of first body portion 12 includes four openings 18 arranged in a generally triangular arrangement 35 consisting of a single opening at the apex of the triangular arrangement and three openings at the base of the arrangement. The openings may be in the form of bores, 6385658_1 (GHMatters) P89896.AU.1 PCABRAL - 15 channels, apertures and the like. In other forms of the invention, each plate can include any number of openings in any spatial arrangement. 5 Openings 18 provide small aquatic species such as fish and eels access to the hollow interior of the submersible structure. Openings 18 also improves aeration within the hollow interior of submersible structure 10 by allowing fluid to circulate through openings 18 and exiting through 10 opening 16 at or around the apex of the structure (Figure 5). Fluid flowing across submersible structure 10 enters openings 18 and is redirected in a generally perpendicular 15 direction exiting through opening 16 (the fluid flow path is illustrated by arrow X in Figure 5). This dissipates energy of the fluid in its original direction of travel towards a plate of the first body portion. 20 Each plate further includes grooves 20 that provide attachment sites for aquatic life, such as mussels, barnacles and aquatic plants. In another form of the submersible structure, first body portion 12 excludes openings 16 and/or grooves 20. Grooves 20 are typically in 25 the form of deep channels that curve around the surface of each plate to provide attachment sites for aquatic species. The curved nature of the grooves enhances the grip of the aquatic species onto the plate. 30 It is preferred that the textures are positioned horizontal to the second body portion to improve the likelihood of trapping spats and/or spores that are carried by waves striking the first body portion. 35 In this regard, when waves strike directly at a plate of the first body portion, the waves are likely to travel in an upwardly direction to the first body portion. Having 6385658_1 (GHMatters) P89896.AU.1 PCABRAL - 16 horizontal textures improves the likelihood of spats and/or spores carried by the waves to be caught by an upper surface of each horizontal texture. In contrast, it is more likely that these spats and spores would travel 5 through vertical textures instead of being trapped within the textures because of a lack of an upper surface to catch the spats and/or spores. Second body portion 14 comprises a substantially 10 triangular plate that generally supports first body portion 12 on substrate 15. Second body portion 14 reduces the likelihood of damage to the base of first body portion 12 when resting on substrate 15 by providing a flat surface for the structure to rest on. In contrast, if the 15 first body portion rests directly onto substrate 15, the edges of the plates in direct contact with the substrate risk being damaged when impacting substrate 15. The second body portion rests on substrate 15 of the 20 aquatic environment to shield the soil beneath second body portion 14 from being washed away. In one form of the invention, first body portion 12 includes opening 22 for reducing accumulation of debris, 25 such as for example, shells, bones and the like in the submersible structure. The opening may also be located at or about a bottom corner of a plate of the first body portion. 30 Opening 22 is located at the interface between the first and second body portions to allow fluid to enter the submersible structure through the opening and exit through any one of the other openings in the submersible structure to remove any debris collected in the submersible 35 structure. In another form of the invention, second body portion 14 6385658_1 (GHMatters) P89896.AU.1 PCABRAL - 17 may include one or more passages on its top surface to reduce accumulation of debris, such as for example, shells, bones and the like in the submersible structure. 5 In operation, the four plates of the first and second body portions are transported individually in a disassembled condition to the target location and assembled onsite using adhesive to bind the edges of the plates to one another to form a hollow truncated pyramid. Once 10 assembled, submersible structure 10 is tethered by chain 24 through opening 16 and lowered into the fluid in an upright position, removing the need to orientate submersible structure 10 in the fluid. 15 Second body portion 14 may include a connector such as a U-bolt to receive a hook attached to an end of tether 24. The connector is set into second body portion 14 during the manufacturing process. The connector can be made of stainless steel or other corrosion resistant material. 20 Tether 24 assists in adjusting the position of one submersible structure relative to another in a spatial arrangement to form an artificial reef and allows the structures to be manoeuvred using derricks, cranes and the 25 like. The submersible structures can also be manually manoeuvred from a boat without the need for a diver to enter the body of fluid. Tether 24 can be removed from the connector after the submersible structure is manoeuvred into position. 30 Importantly, submersible structure 10 functions as an aquatic habitat for aquatic life. Mussels and barnacles can grow on the surface of first body portion 12 and small aquatic life can reside in the hollow interior of the 35 submersible structure 10. In another form of the invention, a plurality of 6385658_1 (GHMatters) P89896.AU.1 PCABRAL - 18 submersible structures 10 can be arranged to abut each other to form artificial reef 26 that substantially covers the substrate beneath the submersible structures, which can be a bed of a body of fluid such as the sea, river, 5 ocean, lake or the like (Figure 3). This arrangement reduces exposure of the underlying substrate to the body of fluid and consequently reduces soil erosion. The size of artificial reef 26 can be tailored by 10 adjusting the number of submersible structures abutting each other. This allows the artificial reef to provide a habitat for aquatic life of different sizes, such as for example, large aquatic species such as turtles and stingrays that can reside in the space between each 15 submersible structure of the artificial reef, and small aquatic species such as fish and eels that can reside in the hollow interior of each submersible structure. The arrangement of submersible structures of artificial 20 reef 26 may also redirect fluid flow substantially in one direction. It is believed that the location of an opening at or around the apex of each submersible structure 10 allows fluid flowing across the artificial reef through the openings 18 of the first body portion to be redirected 25 through opening 16 generally in an upward direction away from the second body portion (Figure 5). This fluid redirection reduces energy in the original direction of travel and reduces soil erosion. It also aerates the interior hollow of the submersible structure. 30 Not wanting to be bound by theory, it is believed that the collective redirection of fluid flow through each structure 10 is substantially in one direction, travelling across the first body portion through openings 18 and 35 upwards from the hollow interior and exiting through opening 16. It is believed that this fluid flow improves aeration of artificial reef 26 and energy dissipation of 6385658_1 (GHMatters) P89896.AU.1 PCABRAL - 19 fluid flowing across and through the artificial reef. The submersible structures of artificial reef 26 can also be arranged to align openings 18 of first body portion 12 5 with the same openings of another abutting submersible structure 10 to form a plurality of fluid channels 28 between each submersible structure 10 to improve fluid flow through the artificial reef (Figure 4). Fluid channels 28 may also allow aquatic species improved access 10 between the structures of the artificial reef. Alternatively, each submersible structure of the artificial reef is arranged such that the openings on each plate of the submersible structure are misaligned with the 15 same openings of another abutting submersible structure 10 to disrupt fluid flow through the artificial reef. It is believed that this arrangement improves dissipation of energy of fluid flowing through the artificial reef by 20 preventing uninterrupted fluid flow through the artificial reef. Thus, submersible structure 10 provides a plurality of surfaces and openings to control fluid flow across and 25 through the submersible structure. It is believed fluid flow control dissipates energy from a body of fluid from its original direction of travel to provide advantages including reducing soil erosion and reducing wave buffeting of water craft in the vicinity of the 30 submersible structure. The fluid flow control also improves aeration of the hollow interior of the submersible structure and its surroundings to encourage growth of aquatic species in the submersible structure. 6385658_1 (GHMatters) P89896.AU.1 PCABRAL - 20 In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as 5 "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention. 6385658_1 (GHMatters) P89896.AU.1 PCABRAL

Claims

1. A submersible structure for forming an aquatic habitat on a substrate comprising a first body 5 portion for providing shelter and attachment sites for aquatic life and a second body portion being a plate for supporting the first body portion on the substrate, the second body portion for resting on the substrate to shield the substrate beneath the second 10 body portion from erosion, the first body portion being generally radially symmetrical and comprising a plurality of plates that are angled relative to each other and angled relative to the plate of the second body portion to form a hollow structure for aquatic 15 life to reside in, the first body portion including at least one opening for the aquatic life to enter the hollow structure and/or for fluid circulation within the hollow structure, wherein an opening between the first and second body portions reduces 20 accumulation of debris within the submersible structure.

2. A submersible structure as claimed in claim 1, wherein the plates of the first body portion are 25 connectable to each other at an angle of less than 90 .

3. A submersible structure as claimed in either claim 1 or 2, wherein the first body portion forms a 30 generally pyramidal shape.

4. A submersible structure as claimed in any one of the preceding claims, wherein each plate of the first body portion is connected to the plate of the second 35 body portion at an angle of less than about 900.

5. A submersible structure as claimed in claim 4, 6385658_1 (GHMatters) P89896.AU.1 PCABRAL - 22 wherein the angle is from about 80' to about 18'.

6. A submersible structure as claimed in claim 5, wherein the angle is at or about 700. 5

7. A submersible structure as claimed in any one of the preceding claims, wherein each plate of the first body portion includes at least one opening. 10

8. A submersible structure as claimed in any one of the preceding claims in which the first body portion has an apex position, wherein the apex portion includes an opening to redirect fluid flowing through the first body portion. 15

9. A submersible structure as claimed in any one of the preceding claims, wherein the second body portion includes a connector in the form of a U-bolt for connecting the structure to a tether. 20

10. A submersible structure as claimed in any one of the preceding claims, wherein the first body portion is textured to improve attachment of aquatic life onto the first body portion. 25

11. A submersible structure as claimed in claim 10, wherein textures on the first body portion are positioned horizontal to the second body portion to improve the likelihood of trapping spats and/or 30 spores striking the first body portion.

12. A submersible structure as claimed in any one of the preceding claims, wherein each plate of the first body portion is connectable to each other by 35 adhesion.

13. A submersible structure as claimed in any one of the 6385658_1 (GHMatters) P89896.AU.1 PCABRAL - 23 preceding claims, wherein the first and the second body portions are connectable by adhesion.

14. A submersible structure as claimed in any one of the 5 preceding claims, wherein the opening between the first and second body portions is an open channel located at a base of the first body portion.

15. A submersible structure as claimed in any one of 10 claims 1 to 13, wherein the opening between the first and second body portions is an open channel located at a top surface of the second body portion.

16. A method for creating an artificial reef on a 15 substrate comprising a plurality of submersible structures as claimed in any one of claims 1 to 15, including the step of arranging the submersible structures to abut each other to form an artificial reef in a compact arrangement that does not expose 20 the substrate to degradation.

17. An artificial reef comprising a plurality of submersible structures as claimed in any one of claims 1 to 15, wherein the submersible structures 25 abut each other to form a compact artificial reef in an arrangement that does not expose the substrate to degradation.

18. An artificial reef as claimed in claim 17, wherein 30 the artificial reef is arranged such that the openings on the first body portions of the plurality of submersible structures are aligned to form a plurality of fluid channels. 35

19. An artificial reef as claimed in claim 17, wherein the artificial reef is arranged such that the openings on the first body portions of the plurality 6385658_1 (GHMatters) P89896.AU.1 PCABRAL - 24 of submersible structures are misaligned to disrupt fluid flow through the artificial reef.

20. A submersible structure for forming an aquatic 5 habitat on a substrate, a method for creating an artificial reef on a substrate and/or an artificial reef substantially as herein described with reference to the accompanying drawings. 6385658_1 (GHMatters) P89896.AU.1 PCABRAL