DIY sharkbanz

[WetSEAL]

The risk of shark attacks is low, and the risk of shark deaths is even lower. Usually when sharks attack they take a bite, then let go. With that said, it does still happen, and sharks are attracted to high contrast colors, such as bright white / yellow/ etc that you might have selected for underwater visibility. If you're wearing black, and your flippers are bright colored and flipping around, it's easy to see how a shark might confuse that with a brightly colored fish.

Sharkbanz – Shark Deterrent Bands

The sharkbanz looks like a pretty cool device. It has a strong repulsive effect on sharks in the last few feet before they take a bite, and doesn't require batteries. There seems to be quite a bit of independent peer reviewed research confirming that this works as well.

Seems like it would make sense to attach one of these onto each flipper, at the very least. Too bad they cost $75 right??

Looking into the patent and provided info, it seems that this is just a simple Ferrite C8 magnet encased in a wrist band. Based on the size of the band, it looks like the ferrite must be about 2" x 1" x 0.5" or thereabaouts.

Here you can buy magnets of about those same dimensions for about $0.25 cents each:

MAGNET4LESS-APPLIED MAGNETS-Neodymium Magnets-Rare Earth Magnets-Ceramic Magnets-Industrial Magnets-Magnets Wholesale To The Public

At this cost, seems like a no-brainer solution to attach one to each of your fins, as there is really nothing to lose

 

[lucca brassi]

M aybe shark broke some tooth because Lorenzini cells work different ( electric field and not magnet field )

 

[Bubblesong]

How heavy are they? Why not use them in place of a dive weight?
I was planning on painting giant eyeballs on my fins to discourage “following” but these magnets could be useful, if they don’t weigh down fins too much.

 

[diversteve]

You really want a shark to get close enough to be affected by a magnet?

Good luck with that.

I'd be concerned it would affect a compass - or a digital compass in your computer.

The active shark systems put a current in the water - the magnetic field is just a side effect. The current is what messes with their Ampules of Lorenzii.

I've seen sharks "twitch" when a strobe fires so it does affect them somehow.
But they still came in for the feed.

 

[Rred]

First off, if a magnet did some good, I'd invest in the rare earth magnets that are WAY more powerful than a cheap ceramic magnet. Of course that's a problem, by the time they get to be silver dollar size they can really bite at your flesh if you get in their way.

But 3? 4? years ago I saw a PBS special, probably hosted by Alan Alda, where researchers were hiding a rather larger and more powerful magnet behind a curtain, and every time the shark charged for the bait--it turned away and zoomed off, if the magnet was there. When the magnet wasn't there, it took the bait.

There is at least *some* basis for magnets doing something. Iddy biddy ceramic ones...maybe not so much.

 

[diversteve]

It's your money..

Easy way to check - order your magnets then go kick your fins in a shark's face and see what happens....

I've dpve with a lot of sharks at both a feed and where they naturally occur. So has my buddy. I have yet to be even approached - much less attacked by a shark - usually it's me chasing them to film. I did get hit once in the side by a fin as the shark misjudged going past me to the bait.

My buddy once had one stay a few feet behind him off Cayman's East End once but that was when they were culling Lionfish in the area so the shark was hooing he was.

If you could work on a damselfish repellent - that would be useful. They;re fearless when protecting their nests and they bite...

 

[diversteve]

Next time I'm diving somewhere where there's a larger magnet hiding behind a curtain I'm sure I'll feel safer...

You could carry one with you on a scooter.But I've seen sharks off FL go for them - attracted bu the unusual noise and motion.

 

[WetSEAL]

M aybe shark broke some tooth because Lorenzini cells work different ( electric field and not magnet field )

A changing magnetic field (eg, caused by a moving permanent magnet) induces an electrical current in nearby conductors (eg, water). This would make a permanent magnet attached to extremities particularly good at generating electrical fields which the sharks can detect using their ampullae of Lorenzini.

You really want a shark to get close enough to be affected by a magnet?

Good luck with that.

If there was a magical device that reliably repels sharks at longer distances, which also is small and portable and costs less than $1, then I'm sure we'd be interested to try it. For now, we only have a small, portable device that costs less than $1 which repels sharks from a couple feet away.

Whether or not you encounter a shark really has nothing to do with whether or not you are wearing a magnet. We know that it does not attract sharks from longer ranges, because their only way of detecting magnetic (hence, induced electric) fields is via their ampullae of Lorenzini, can only detect electric fields at very close ranges like a few feet. They use it to suss out prey that is hidden under the sand.

In the unusual scenario that you have encountered a shark already, there will be some range at which point it can sense your electric fields before it is uncomfortable, but this is probably well within it's sight range and already knows you're there. Perhaps it might cause the shark to be more likely to check you out. However, it's very well documented fact that chum that has magnets on it doesn't get eaten, whereas chum without magnets does get eaten. Simple as that.

Note: they say it doesn't work well against Great Whites because they have a tendency to basically charge from a greater distance

Here are just a few of the peer reviewed research articles on the subject:
The use of permanent magnets to reduce elasmobranch encounter with a simulated beach net. 2. The great white shark (Carcharodon carcharias) - ScienceDirect
Assessment of permanent magnets and electropositive metals to reduce the line-based capture of Galapagos sharks, Carcharhinus galapagensis - ScienceDirect
https://www.researchgate.net/public..._in_water_show_promise_for_bycatch_mitigation
https://www.int-res.com/articles/esr2015/26/n026p243.pdf
The effects of neodymium-iron-boron permanent magnets on the behaviour of the small spotted catshark (Scyliorhinus canicula) and the thornback skate (Raja clavata) - ScienceDirect

I'd be concerned it would affect a compass - or a digital compass in your computer.

This is definitely something to keep in mind, and why I think it makes more sense to put them on the feet/flippers, which are far enough from your compass that I don't think it would make a difference. Also because if you're wearing brightly colored flippers, these are the part of you that's most likely to look like a fish, so it's where a repulsive force would be best.

First off, if a magnet did some good, I'd invest in the rare earth magnets that are WAY more powerful than a cheap ceramic magnet. Of course that's a problem, by the time they get to be silver dollar size they can really bite at your flesh if you get in their way.

I had the same thought. That's why I purchased a couple neodynium magnets instead of C8 ferrite. Cost about $5 each.
I got ones with a hole in them, plan is to screw them embed inside of the rubber show hole of the flippers so that it can't come in direct contact with any metal bits that would be difficult to get stuck onto.

 

[lucca brassi]

A changing magnetic field (eg, caused by a moving permanent magnet) induces an electrical current in nearby conductors (eg, water). This would make a permanent magnet attached to extremities particularly good at generating electrical fields which the sharks can detect using their ampullae of Lorenzini.

- simple question can any animal generate magnetic field ( even from their own electric potentials ) .........no ! But they can sense Earth magnetic field !

- Water is dimagnetic, which means that it exerts a weak magnetic field, and repels other magnetic fields. If a magnet is suspended over water, the water's dimagnetism will repel the magnet. This weakens the magnet's effect on other objects. When salt is added to water, it weakens the water's magnetic field further, so that it ceases to have any significant effect on other magnetic fields. Problem at your statement is magnet permealibility of salt water which cause magnetic field

- when you dive with magnets on hands or legs you cause static magnetic field ( that moves very very very slow ) and not alternating magnet field. Animals produce static electric fields (DC ) and not alternating (AC)

(PS : shaking magnet in coil in some batterys- you made AC current , for DC you need - diode and you get ''half wave DC '' not clean DC and you have far lower power than clean DC .

good luck with sharks

 

[diversteve]

Have you ever dove with sharks? I have a bunch of times.. I even dropped right on top of a reef shrark one once, kicked him in the back and you never saw a shark leave in a bigger hurry. The captain was nearby inspecting the boat and I thought he was going to choke - from laughter.

I filmed in the middle of a feed - once. The dive crew allowed me to get closer than the circle of divers. Probably had to do with earlier that day I was seen being circled by 18 curious reef sharks (and 2 bulls) during a dive - I filmed while I fended them off. My buddy counted them.

I had a small shark take interest in a piece of bait about a foot from my crotch. I was more concerned that the DM with the polespear mght miss than anything the shark was going to do - he was so intent on the bait I doubt he knew I was there.

Are you afraid of them? There's plenty of excellent diving where you'll likely never see one - Bonaire/Curacap being two nearby examples. Roatan - unless you go to the shark dive.

It just seems silly to me.

fyi - my last words in this thread...hope it works for you.