Outdoors

Handheld eSpear is designed to deter sharks with an electrical field

The eSpear can be carried while swimming, or put in an optional thigh holster
The eSpear can be carried while swimming, or put in an optional thigh holster
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The eSpear runs for a claimed one to two hours per inductive charge of its lithium battery
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The eSpear runs for a claimed one to two hours per inductive charge of its lithium battery
The eSpear can be carried while swimming, or put in an optional thigh holster
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The eSpear can be carried while swimming, or put in an optional thigh holster
The eSpear is its activated state, with its two electrodes (silver) exposed
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The eSpear is its activated state, with its two electrodes (silver) exposed

Since at least 2004, surfers, swimmers and scuba divers have been able to buy an electronic shark-deterrent device known as the Shark Shield. Its patented technology is now being offered in a handheld speargun-like gadget, called the eSpear.

Developed in Australia, the original Shark Shield is worn on the thigh or ankle, or it can be mounted on a surfboard. Once in the water, it forms a three-dimensional electrical field around itself. The claim is that when sharks enter this field, their electro-receptive system is disrupted, causing them to experience muscle spasms and severe discomfort. Although they're not actually harmed, they are motivated to immediately leave the area.

Sydney-based Ocean Guardian's eSpear utilizes that same system, but it takes the form a "gun" that can be carried in an optional thigh holster, then pulled out when needed. If users think that a shark is getting a little too close, they squeeze the trigger. Doing so causes a forward section of the device to slide/pivot out from the main body, exposing two electrodes to the water. This, in turn, instantly creates an electrical field surrounding the device, measuring 1 meter across by 2.5 m in length (3.3 by 8.2 ft).

The eSpear is its activated state, with its two electrodes (silver) exposed
The eSpear is its activated state, with its two electrodes (silver) exposed

As compared to the existing Shark Shield, advantages of the new device include the facts that it only runs (and uses up its battery) when manually activated, and it can be pointed right at approaching sharks. It presumably isn't as effective at guarding against sneak attacks from unseen sharks, however.

And then there's the whole question of how well the deterrent system actually works. Well, a 2016 study conducted by the University of Western Australia determined that the Shark Shield deterred attacks on a bait-loaded canister 90 percent of the time. And in a 2018 study conducted by Australia's Flinders University and Fox Shark Research Foundation, it performed the best out of five commercially-available devices.

Obviously, though, users would still be wise to take all the usual precautions when entering the water.

The eSpear weighs 250 g (8.8 oz), is operational to a depth of 100 m (328 ft), and runs for a claimed one to two hours per wireless charge of its lithium battery – run times will be affected by water temperature. A built-in LED display lets users know when the battery is getting low.

Should you be interested, it's currently the subject of an Indiegogo campaign. A pledge of US$165 will get you a device, when and if it reaches production. The planned retail price is $299.

Source: Indiegogo

4 comments
Nik
That seems fine, but the best and most effective way of not being eaten by sharks, is not to swim with them, which is the method I would choose.
D[]
These devices are great for deterring curious sharks or discouraging aggressive sharks who are coming too close (like when a diver has entered their swim pattern area or when sharks are trying to feed on a spearfisherman's take). These devices are not effective for the more commonly reported in the media surprise attacks. The low effective range means that for surfers, swimmers, body boarders, etc... these types of devices are worthless. The "shark shield" type devices, deterred sharks that were investigating bait, but studies have shown that they do nothing for sharks that are attacking from a stalking position. Stalking sharks attack from an area too far away to be deterred by an electromagnetic field.
Arandor
The article says, "Obviously, though, users would still be wise to take all the usual precautions when entering the water." What "usual precautions" will stop a shark attack? I grew up on the beach and the only precaution I ever knew was not to go in the water.
Expanded Viewpoint
Has anyone tried using a coil of wire that is energized with a burst of electricity every few seconds, sort of like a strobe light? If sharks have a particular frequency that they don't like, an oscillator circuit could be set up to generate it, and then a transistor could switch off and on every 15 seconds or so, sending the noxious frequency to the coil, which would radiate a magnetic field of that frequency into the water. Being totally passive, one wouldn't have to worry about turning it on when sharks get too close, just when getting in. It could even be made to where it would turn itself on when entering the water! Randy
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