AU2003225326A1

AU2003225326A1 - Improved aquatic vessel hull

Info

Publication number: AU2003225326A1
Application number: AU2003225326A
Authority: AU
Inventors: Michael Wescombe-Down
Original assignee: SeaChange Technology Holdings Pty Ltd
Current assignee: SeaChange Technology Holdings Pty Ltd
Priority date: 2002-05-06
Filing date: 2003-05-06
Publication date: 2003-11-17
Also published as: ZA200408981B; BRPI0309899A2; BRPI0309899A8; CN1653702A; JP2005524571A; US20060016379A1; AUPS214202A0; WO2003094370A1

Description

WO 03/094370 PCT/AU03/00534 1 IMPROVED AQUATIC VESSEL HULL TECHNICAL FIELD This invention relates to devices and applications of generating electromagnetic fields within a body of water to repel aquatic creatures such as sharks. BACKGROUND TO THE INVENTION Numerous devices are known for the purpose of repelling aquatic creatures. The majority of these devices are designed to generate an electromagnetic field in close proximity of a diver or to form a barrier or boundary in the nearby water. Most studies are conducted on the aquatic creature sub-group of elasmobranchii, otherwise known as sharks. Most shark repelling apparatus use electromagnetic pulses, delivered into the water by submerged antennae or electrodes, to create an appropriate electromagnetic field in the vicinity of a swimmer, diver or general water recreationist. Various types of pulse signal generators are used, the characteristics of which include a specification of signal duration, repetition rate, amplitude and pulse rise time. The value or ranges of each characteristic are carefully selected so as to create the electromagnetic field deemed most effective. In the past, such signal generators have been disposed on the body of the swimmer or as a separate unit to be used in an area that is desired to be shark-free. Not only are individuals at risk from being attacked by sharks, sometimes small aquatic vessels such as surfboards, kayaks, rafts and small boats can be disturbed by sharks.

WO 03/094370 PCT/AU03/00534 2 It is an object of the present invention to provide a means by which shark-repelling electromagnetic fields can be generated about an aquatic vessel to reduce the risk of the vessel being disturbed by sharks. SUMMARY OF THE INVENTION According to a first aspect of the present invention, there is provided an aquatic vessel hull adapted to support at least two electrodes connectable to an electromagnetic field signal generator, in use, the electrodes generating an electromagnetic field in a volume of water about the vessel, the electromagnetic field acting to repel selected aquatic creatures. Preferably, the aquatic vessel hull includes at least two recesses for receiving one each of the at least two electrodes, such that the at least two electrodes do not protrude substantially beyond the upper surface of the hull. Preferably, the aquatic vessel hull further includes a channel connecting said recesses, said channel adapted to accommodate an electrode cord terminating at each end being one of said at least two electrodes. Preferably, the recesses are formed so as to allow maximum efficiency of distribution of the electromagnetic field generated by said electrodes when in use. According to a second aspect of the present invention, there is provided an aquatic vessel hull incorporating at least two electrodes, connectable to an electromagnetic field signal generator, in use, the said electrodes generating an electromagnetic field in a volume of water about the aquatic vessel, said field acting to repel selected aquatic creatures. Preferably, the electrodes do not substantially protrude beyond the surface of said hull.

WO 03/094370 PCT/AU03/00534 3 Preferably, the electrodes are received in corresponding recesses in said hull. Preferably, the electrodes constitute respective ends of a cord, which is received in a channel in said hull connecting said recesses. Alternatively, the electrodes consist of respective conductive plates. Preferably, the recesses are formed so as to allow maximum efficiency of distribution of the electromagnetic field generated by said electrodes when in use. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a side elevation of an aquatic vessel hull according to a preferred embodiment of the present invention; Figure 2 shows a plan view of the top of the aquatic vessel hull of Figure 1; Figure 3 shows a plan view of the bottom of an aquatic vessel hull of Figure 1; Figure 4 shows the hull of figure 3 with the electrode cord inserted; Figure 5 shows a detail of the recess for receiving the electric field signal generator; Figure 6 shows a cross-sectional view of the recess along the lines A-A' of Figure 3. Figure 7 shows an alternative arrangement of the hull of Figure 1. Figure 8 shows the hull of figure 1 in use, generating an electromagnetic field. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT It will be understood that the phrase "aquatic vessel" refers to any suitable vessel including surfboard, surf rescue board, kayak, sailboat, rowboat, ship and water skis to be worn on the feet of a user. A typical aquatic vessel hull 10 is shown in side elevation in Figure 1. Provided in hull 10 is channel 11 for accommodating a cord (not shown) having electrodes at either end of the cord. The type of electrode cord that will be suitable for this WO 03/094370 PCT/AU03/00534 4 application is the subject of a co-pending PCT Patent Application No PCT/AU02/01297, the contents of which are hereby incorporated by reference. It will be appreciated however, that any other suitable electrode arrangement may be used. Hollowed recesses 12 and 13 accommodate the electrodes (not shown) of the electrode cord which in use, is slid through channel 11 until both electrodes are in place in respective recesses 12 and 13 and then secured in place by any appropriate means. Figures 2 and 3 show these features in a top plan view and a bottom plan view respectively. Figure 4 show the view of figure 3 (bottom view), but with an electrode cord 23 inserted in channel 11. Electrodes 24 and 25, being the ends of cord 23 are received in recesses 12 and 13 respectively. Channel 11 may accommodate a fibre glass tube 11a (see Figure 6) through which the electrode cord may be slid. Channel 11 is then covered or filled such that the contour of the exterior surface of hull 10 is maintained. Recesses 12 and 13 are shaped such that exposed electrodes are able to radiate effectively from their position within the hull. As can be seen Figure 6, a preferred range of angles for recesses 12 and 13 is 1000 - 1100. Hull 10 also includes a recess or cavity 14 which is sealable with lid 15. Recess 14 is adapted to receive and store an electric field signal generator. Such signal generators are well known and one such suitable generator is described in Australian Patent No 669806. Any suitable electric field signal generator however, may be used.

WO 03/094370 PCT/AU03/00534 5 Channel 14a provides a means by which the signal generator can be connected to the electrodes (see figure 5). It is also within the concept of the present invention to provide a hull having incorporated therein electrodes which are connectable to a suitable signal generator. The electrodes may consist of metal plates or a conductor of any other suitable configuration, which may be attached to, or form an integral portion of the hull. For example, a portion of the front end of the hull may be made from or include a metal or other conductive plate providing a first electrode, while a portion of the back end of the hull may be made from a metal or other conductive plate, forming a second electrode. Such an arrangement is shown in figure 7, in which electrode plates 20, 21 are shown incorporated within hull 10. Upon connection to a suitable signal generator, these plates may radiate the required electromagnetic field to produce a shark-deterring region within the water about the hull. Figure 8 shows the hull of figure 1 incorporating the cord with electrodes housed in channels 12 and 13 (not shown), in use in a body of water 30. When activated the signal generator (not shown) causes the electrodes (not shown) to generate electromagnetic field 40 about hull 10, forming a shark-repelling region about the vessel. This reduces the risk of a shark attacking the vessel, or a person who is in the water, and near the vessel, such as a person who has fallen off or out of the vessel. While the above has been described with reference to a preferred embodiment, it will be understood that further modifications and alterations may be made within the scope of the present invention.

Claims

1. An aquatic vessel hull adapted to support at least two electrodes connectable to an electromagnetic field signal generator, in use, the electrodes generating an electromagnetic field in a volume of water about the vessel, the electromagnetic field acting to repel selected aquatic creatures.

2. An aquatic vessel hull according to claim 1, wherein said aquatic vessel hull includes at least two recesses for receiving one each of the at least two electrodes, such that the at least two electrodes do not protrude substantially beyond the surface of the hull.

3. An aquatic vessel hull according to claim 2 wherein said aquatic vessel hull further includes a channel connecting said recesses, said channel adapted to accommodate an electrode cord terminating at each end in one of said at least two electrodes.

4. An aquatic vessel hull according to claim 3 wherein said recesses are formed so as to allow maximum efficiency of distribution of the electromagnetic field generated by said electrodes when in use.

5. An aquatic vessel hull incorporating at least two electrodes, connectable to an electromagnetic field signal generator, in use, the said electrodes generating an electromagnetic field in a volume of water about the aquatic vessel, said field acting to repel selected aquatic creatures.

6. An aquatic vessel hull according to claim 5 wherein said at least two electrodes do not substantially protrude beyond the surface of said hull. WO 03/094370 PCT/AU03/00534 7

7. An aquatic vessel hull according to any one of claims 5 or 6 wherein said at least two electrodes are received in corresponding recesses in said hull.

8. An aquatic vessel hull according to claim 7 wherein said at least two electrodes constitute respective ends of a cord, which is received in a channel in said hull connecting said recesses.

9. An aquatic vessel hull according to claim 6 wherein said at least two electrodes consist of respective conductive plates.

10. An aquatic vessel hull according to claim 7 wherein said recesses are formed so as to allow maximum efficiency of distribution of the electromagnetic field generated by said electrodes when in use.