[0001] This international patent application claims priority from Australian Provisional Patent Application No. 2017900997, entitled "ANTENNA ARRANGEMENT FOR A WATER CRAFT" filed on 21 March 2017, the contents of which are to be taken as incorporated herein by this reference.

TECHNICAL FIELD

[0002] This invention relates to devices for affecting the behaviour of chondrichthyans such as rays, skates and sharks.

BACKGROUND

[0003] Recorded shark attacks have steadily increased in recent times, while at the same time the desire to offer conservation and protection to sharks has also increased as populations dwindle significantly.

[0004] It is known that all chondrichthyans such as predatory sharks have highly sensitive electrical receptors called the "Ampullae of Lorenzini" located in their snouts. These tiny gel filled sacs sense electrical current from prey, but only at very close distances, typically less than one metre.

[0005] Conventional shark repelling devices are arranged to generate a localised electrical field that causes the ampullae to spasm and consequently the shark to move away from the generated field.

[0006] One typical such conventional device is described in US 7,412,944 which describes a device including a trailing antenna with two electrical contacts in electrical communication with the surrounding water, and an electric field generator arranged to generate an electric field across the contacts of sufficient intensity to produce the desired effect to the ampullae of a shark that is sufficiently close to the antenna. However, for some aquatic activities, such as surfing, it is undesirable to have a trailing antenna as such an arrangement may produce undesirable drag. [0007] It would be desirable to provide an antenna arrangement which provides an electric field which is suitable for repelling sharks, but which has reduced drag.

SUMMARY

[0008] According to one aspect of an embodiment of the disclosure there is provided an antenna arrangement for a watercraft including:

a pattern of conductive ink forming an electrical circuit with at least one pair of spaced apart electrodes;

wherein the antenna arrangement is applied or is applicable to an exterior surface of the watercraft.

[0009] In embodiments, the antenna arrangement is configured for use with a

chrondrichthyan repelling system.

[0010] In this specification, reference to the term "conductive ink" denotes an electrically conductive ink having a low electrical resistivity. Preferably, the antenna arrangement provides an electrical circuit having a resistive impedance of less than 300 milli-ohms over the total area of the antenna arrangement.

[0011] The antenna arrangement may be applied as, or be applicable to form, a thin layer or film on the exterior surface of the watercraft. The exterior surface will be a surface of the watercraft which is in contact with water when the watercraft is in use.

[0012] In this specification, references to the term "thin" in the context of a thin film or layer denotes a layer or film having a surface height which projects from the exterior surface by less than 600 /m. In an embodiment, the surface height is less than 500 /m. In another embodiment, the surface height is less than 400 /m. In still another embodiment, the surface height is less than 300 /m.

[0013] The term "surface height", where used in this specification, will be understood to denote the maximum extent to which the antenna arrangement projects outwardly from the exterior surface of the watercraft. The "surface height" will thus be the difference between an outermost surface of the antenna arrangement and the exterior surface of the watercraft to which the antenna arrangement is applied. [0014] The watercraft may include a vessel, such as a dinghy, a power boat, a sailing boat or the like. Alternatively, the watercraft may include a personal watercraft such as a jet ski, canoe, kayak (such as an ocean going kayak), surf board, stand up paddle board, wave board, kite surfing board, wave ski, water ski or the like.

[0015] The pattern of conductive ink may be formed from any suitable conductive ink. Examples of suitable conductive inks include silver, carbon, silver chlorides and graphene carbon. An ultra low cure silver composite conductive ink, such as conductive inks marketed by from DuPont™ as PE827 and PE828 inks may be used. Other suitable conductive inks may include graphene inks.

[0016] Preferably, the pattern of conductive ink may be applied to a substrate using a suitable printing process. Examples of a suitable printing process include inkjet printing and silk screen printing. Other methods for printing conductive inks would be known to a person skilled in the art. In embodiments, the pattern of conductive ink is applied to the substrate to form the antenna arrangement as a unitary structure which is applicable to the exterior surface as a single piece.

[0017] The pattern of conductive ink may include a plurality of conductive tracks or traces having a surface height of less than 30 /m and a track width depending on electrical current requirements.

[0018] Each of the plurality of conductive tracks or traces may route between a respective one of the electrodes and a respective at least one termination area or point. Each of the at least one termination areas or points preferably provides a landing or pad suitable for forming an electrical connection with additional and external conductive elements to thereby extend the electrical circuit. The electrical connection may be formed by soldering, printing or gluing or otherwise joining the additional conductive elements to a respective termination area or point. In some embodiments, an electrical connection to a termination area or point maybe formed by overlaying one conductive ink over another conductive ink.

[0019] As will be described below, the pattern of conductive ink may be applied directly to the exterior surface of the watercraft, such as a portion of an exterior surface of a body or hull of the watercraft, or it may be applied to a separate substrate which is applied or is applicable to the exterior surface of the watercraft. The exterior surface may include a surface of a control or stabilising element of the watercraft, such as a rudder, keel, or fin.

[0020] The spaced apart electrodes may be considered as forming a "pair" of electrodes such that when the antenna arrangement is applied to the exterior surface of the watercraft, the pair of electrodes are spaced apart across an extent of generally planar surface of the watercraft located, or intended to be located, below the water line of the watercraft when in use.

[0021] The spacing between the electrodes may vary according to the size and/or configuration and/or intended use of the watercraft. For example, in an embodiment which is applied or applicable to an exterior surface of a surf board, the spacing between the electrodes may be between 1100mm and 1130 mm. In one embodiment, the electrodes are spaced between 600 mm and 800mm apart.

[0022] In an embodiment, each electrode may be formed integrally with the pattern of conductive ink by suitable application of the conductive ink to an area of the substrate. In another embodiment, each electrode may include an additional layer of a suitable conductive material in electrical connection at least one of the conductive ink tracks or routes of the pattern of conductive ink to form the electrical circuit therewith.

[0023] The additional layer of conductive material for forming a respective electrode may include an additional printed layer of a conductive material having a higher electrical conductivity (that is, lower electrical resistance) that the conductive ink. One example of a suitable conductive material is graphene. Alternatively, the additional layer of conductive material may include a thin layer of a metallic material, such as layer of stainless steel. In embodiments including graphene electrodes, an electrode surface height of 25 /m may be possible. A graphene electrode may be applied to the substrate using a suitable printing process, such as a wet-screen printing process, ink-jet printing process or gravure printing process. [0024] Each electrode may be shaped and arranged to have a suitable configuration for projecting an electric field for repelling a chondrichthyan. In one embodiment the electrodes have a surface area of between 50 and 100 cm ^" . The shape and surface area may vary according to size of the watercraft and the density and/or field strength of the electric field.

[0025] In embodiments including a separate substrate, the substrate may include a polymer substrate, such as a polyester substrate. Examples of suitable polyesters include polyethylene terephthalate (PET) and polyethylene naphtholate (PEN). Other polymers suitable for use as the substrate include polycarbonate, PVC, acrylic, polystyrene and polyvinylidene difluoride (PVDF).

[0026] It is not essential that a separate substrate be provided since in some embodiments the conductive ink maybe applied directly to the exterior surface of the body or hull of the water craft provided that the exterior surface comprises an insulting material.

[0027] In an embodiment, the antenna arrangement includes means for connecting the antenna arrangement to a control unit to form an electrical interface therewith. The control unit may include a processor, a power source and a signal generator. Sensing means may also be provided to provide to the processor with one or more a sensed signals having an attribute depending on a respective associated one or more associated spaced apart electrodes being in contact with water.

[0028] In embodiments, the antenna arrangement includes a rounded edge defining a permitter of the antenna arrangement, such that the rounded edge is shaped to reduce hydrodynamic drag in use.

[0029] Accordingly, in another embodiment of the disclosure, there is provided a watercraft including:

a body or hull; and

at least one antenna arrangement including a pattern of conductive ink forming an electrical circuit with at least one pair of spaced apart electrodes;

wherein the antenna arrangement is applied or is applicable to an exterior surface of the watercraft as a thin layer. [0030] Preferably, the antenna arrangement is applied as a layer.

[0031] Yet another embodiment of an aspect of the disclosure provides a chrondrichthy an repelling system including:

a watercraft body or hull having an exterior surface located below a waterline of watercraft in use;

at least one antenna arrangement including a pattern of conductive ink providing a plurality of tracks forming an electrical circuit with at least one pair of spaced apart electrodes; and

an electrical signal generator for connection to the spaced apart electrodes;

wherein the antenna arrangement is applied to the exterior surface of the watercraft as a thin layer.

[0032] Yet another embodiment of the disclosure provides a method of forming an antenna arrangement on an exterior surface of a watercraft, the method including:

providing a unitary structure including:

a substrate layer;

a pair of spaced apart electrodes applied to the substrate layer; and a pattern of conductive ink forming an electrical circuit with at least one pair of spaced apart electrodes; and

applying the unitary arrangement to the exterior surface.

BRIEF DESCRIPTION OF DRAWINGS

[0033] Embodiments of the present invention will be discussed with reference to the accompanying drawings wherein:

[0034] Figure 1 is a plan view of an antenna arrangement according to an embodiment of the disclosure;

[0035] Figure 2 is a cross-sectional view of the antenna arrangement shown in Figure 1 taken along the line A- A;

[0036] Figure 3 is an exploded view of the antenna arrangement shown in Figure 1; [0037] Figure 4 is a perspective view of the antenna arrangement shown in Figure 1;

[0038] Figure 5 is a perspective view of a watercraft including an antenna arrangement according to an embodiment of the disclosure; and

[0039] Figure 6 is a block diagram of an antenna arrangement according to an embodiment of the disclosure.

[0040] In the following description, like reference characters designate like or corresponding parts throughout the figures.

DESCRIPTION OF EMBODIMENTS

[0041] Figures 1 to 4 depict an antenna arrangement 10 for a watercraft according to an embodiment of the disclosure. As shown, the antenna arrangement 10 includes a pattern 12 of conductive ink forming an electrical circuit with a pair of spaced apart electrodes 14, 16.

[0042] The illustrated antenna arrangement 10 is depicted as a thin layer antenna including a substrate 18 onto which the pattern 12 of conductive ink is applied. In the present case, an underside surface of substrate 18, and thus the antenna arrangement 10, is affixed to an exterior surface of the watercraft to thereby affix the antenna arrangement 10 to the watercraft. In the illustrated embodiment, an adhesive (not shown), such as an adhesive layer or bonding agent, is be used to affix the antenna arrangement 10 to the watercraft. One example of a suitable adhesive layer is a transfer tape with such as an acrylic adhesive tape marketed as 300LSE by 3M™.

[0043] In the present case, the illustrated embodiment of the antenna arrangement 10 includes a separate substrate 18. However, it is not essential that a separate substrate 18 be provided since in some embodiments the pattern 12 of conductive and the pair of spaced apart electrodes 14, 16 may be applied directly to the exterior surface of the watercraft. Nevertheless, it is preferred that a substrate 18 be provided since it may provide for a more convenient approach for applying the antenna arrangement 10 to the exterior surface of the watercraft. [0044] In the present case, the pattern of 12 of conductive ink includes a plurality of conductive ink tracks 20. Each of the plurality of conductive ink tracks 20 forms an electrical circuit between a respective one of the electrodes 14, 16 and a respective termination area 22, 24. As shown, termination area 22 forms an electrical circuit with electrode 14, whereas termination area or point 22 forms an electrical circuit with electrode 16.

[0045] The conductive ink may include an ultra low cure silver composite conductive ink, such as conductive inks marketed by from DuPont™ as PE827 and PE828.

However, other suitable conductive inks may be used. Example of other suitable conductive inks include graphene inks manufactured by Sigma-Aldrich® and marketed as product numbers 793663 ("Ink-jet Printable Graphene Ink") and 796115 ("Gravure Printable Graphene Ink"). Technical information for these products is available at http://www.sigmaaldrich.com/technical-documents/articles/tec hnology- spotlights/graphene-inks-for-printed-electronics.html.

[0046] Although not shown, an insulating layer may be applied over the conductive ink tracks 20 (including the termination areas 22, 24) and the electrodes 14, 16 to provide a protective seal which hermetically isolates the conductive 20 tracks and the electrodes 14, 16 from the environment in use. In embodiments, the insulating layer is a UV stabilised insulating material.

[0047] In the embodiment shown in Figures 1 to 4, the termination areas 22, 24 provide a landing suitable for forming an electrical connection with additional and external conductive elements to thereby extend the electrical circuit. The electrical connection may be formed by joining the additional conductive elements to a respective termination area 22, 24 using a suitable joining process, such as soldering.

[0048] With reference now to Figure 6, and as will be described in more detail following, in embodiments of the disclosure, the pair of electrodes 14, 16, are included in a respective circuit for radiating an electric field having a field pattern projected by the antenna arrangement 10 when in use. In this way, by suitable application of the antenna arrangement 10 on the exterior surface of a watercraft, a field pattern can be formed which projects from the exterior surface of the watercraft an electric field for repelling chrondri chthy an .

[0049] Each electrode 14, 16 may be formed of any suitable thin conductive material. Examples of suitable materials include graphene, metal, or a conductive polymer. In the present case, each electrode is a metallic electrode made from stainless steel (for example, 316L stainless steel) having a suitable geometric configuration.

[0050] In some embodiments, electrodes 14, 16 may include a plate or mesh-like element. For example, in some embodiments, each electrode 14, 16 may include a woven or grid-like mesh arrangement of a suitably conductive material. In still other

embodiments, the electrodes 14, 16 may be printed, sprayed or otherwise applied as a fluid which cures or sets on the substrate 18 to form an electrical connection with a respective one or more conductive ink tracks 20.

[0051] Each electrode 14, 16 has a configuration which provides an area suitable for radiating an electric field having a desired field pattern projecting from the exterior surface. One example of a suitable electrode configuration is a 110mm x 110mm ovoid shaped electrode having a material thickness of between 300 um and 500 um. Another example of a suitable electrode configuration is a 72 mm x 60 mm ovoid shaped electrode having a material thickness of between 300um and 500um. Yet another example of a suitable electrode configuration is an 88 mm x 80 mm ovoid shaped electrode having a material thickness of between 300/zm and 500/zm.

[0052] In embodiments, the electrodes 14, 16 are arranged to provide an inter electrode separation which allows for a localised (that is, localised to the exterior surface of the watercraft) electric field strength which is effective at repelling chrondri chthy an.

[0053] In preference, each electrode 14, 16 is located so as to provide an inter electrode separation which does not exceed 1130 mm. The particular inter electrode separation may vary between different watercraft types and indeed the intended use of the watercraft. [0054] Figure 5 illustrates a watercraft 100 in the form of a surf board 102. The illustrated surf board 102 includes a body 104 to which an antenna arrangement 10 according to an embodiment of the disclosure has been applied. As shown, the antenna arrangement 10 is affixed to an exterior underside surface of the body 104.

[0055] The illustrated surf board 102 is also fitted with a control unit 106. As described above, terminations 22, 24 electrically connect each electrode 14, 16 to the control unit 106 via a suitable electrical interconnection arrangement 108.

[0056] In the illustrated embodiment, the electrical interconnection arrangement 108 includes a printed flexible conductor, such as a graphene printed flexible conductor, which is affixed to the surf board 102. However it is possible that other types of electrical interconnection arrangement 108 may be used.

[0057] Returning now to Figure 6, in the embodiment illustrated the control unit 106 includes a processor 200, a power source 202 (such as a battery), a signal generator 204, and electrode interface electronics 206. Status indicators 210 (on/off status, power low) are also arranged to be readily viewable by a user of the watercraft.

[0058] Processor 200 may include, for example, one or more processors executing resident configured logic, where such computing devices include, for example, microprocessors, digital signal processors (DSPs), microcontrollers, or any suitable combination of hardware, software and/or firmware containing processors and logic configured to at least perform the operations described herein.

[0059] Processor 200 can include an application specific integrated circuit ("ASIC"), or other processor, microprocessor, logic circuit, or other data processing device. The processor 200 executes embedded application software 212 that interfaces with any resident programs in the memory 214 of the control unit 106. The memory 214 can include read-only or random-access memory (RAM and ROM), EEPROM, flash cards, or any memory common to computer platforms. The control unit 106 may also include a local storage device 216 that can hold applications not actively used in memory 214. The storage device 216 is typically a flash memory cell, but can be any secondary storage device as known in the art, such as an EEPROM, or the like. [0060] The control unit 106 may have installed on it, or may otherwise download, one or more software applications for controlling the operation of the electrodes 14, 16. Such software applications may be stored on the local storage device 216 when not in use.

[0061] Any suitable electrical signal generator 204 can be used, such that it will generate electrical signals for application across the first and second electrodes of an enabled electrode pair to radiate an electric field therebetween that will repel chondrichthyans. An example of one suitable signal generator is described in detail in U.S. Pat. No.

5,566,643 hereby incorporated by reference in its entirety.

[0062] In a broad sense, the above has described a chondrichthyan repelling system for repelling chondrichthyans including at least one pair of electrodes, the repelling system including an electrical signal generator for providing an signal to for generating an electric field across each at least one pair of electrodes which, in use, repel

chondrichthyans.

[0063] It will be appreciated by those skilled in the art that the invention is not restricted in its use to the particular application described. Neither is the present invention restricted in its preferred embodiment with regard to the particular element and/or features described or depicted herein. It will be appreciated that various modifications can be made without departing from the principles of the invention. Therefore, the invention should be understood to include all such modifications within its scope.

[0064] Throughout the specification and the claims that follow, unless the context requires otherwise, the words "comprise" and "include" and variations such as

"comprising" and "including" will be understood to imply the inclusion of a stated integer or group of integers, but not the exclusion of any other integer or group of integers.

[0065] The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement of any form of suggestion that such prior art forms part of the common general knowledge. [0066] It will be appreciated by those skilled in the art that the invention is not restricted in its use to the particular application described. Neither is the present invention restricted in its preferred embodiment with regard to the particular elements and/or features described or depicted herein. It will be appreciated that the invention is not limited to the embodiment or embodiments disclosed, but is capable of numerous rearrangements, modifications and substitutions without departing from the scope of the invention as set forth and defined by the following claims.