Hoseless AI and electrical signals???

[Jeblis]

Do sharks pick up on RF and electrical current? I doubt that a wireless computer puts out any more current into the water than
any other computer/electrical dive watch/light etc. The DO however put out a low power RF signal. (Actuallly any electrical device will put out some RF signal or more generally an EM field) If they pick up on current I doubt the leakage current from a watch/ transmitter etc. would be strong enough for them to detect. The leakage current from a mammal is much higher. Anyway I agree with your point that a wireless transmitter probably does not pose a significant shark risk. The LDS guy was probably just guessing.

Yes, Computers are more likely to fail than a mechanical SPG,
but the overall benefit of having a multiprofile dive algorithm outweighs the risk of failure (IMHO). Rather than diving tables which assume that you spent all of your time at the deepest depth you reached, they adjust based upon how much time you spend at each depth. This gives most people more dive time while still being conservative on no decompression limits. Your
dive tables don't know how much nitrogen you have either.

If they do fail(pretty unlikely if properly maintained) the usual method of recovery is to ascend to your safety stop at 33ft/min and wait almost as long as your air supply lasts. (yes you wont know exactly how much you have, but you're at 15ft... easy ascent if it does run out) Then not dive for 24 hours. For recreational diving this easily falls within the skills learned in OW diving. Tech diving... well you better have a backup.

Training? Yes. No computer can replace proper training. The more the better.

Overly complicated. Well my dive computer makes my life easier. It puts all of my time/SPG/ascent rate/nitrogen loading/oxygen limits all on one display. It also has alarms the let me know if I'm doing something wrong.

Wireless. One less hose to get tangled or caught on something.

A computer is much more accurate as far as depth measurement than a mechanical depth gauge which is usually +/- 8 ft. thats a lot when you calculating on dive tables. Computers are guaranteed to be +/-4 (usually) but they will regularly be accurate to less than a foot.

 

[DuckDive]

What Jeblis said.

Also, for interest's sake and because it's sort of related:

http://www.sharkattacks.com/protecting.htm
http://www.sharkpod.co.za

 

[madmole]

Interestingly enough heard this annecdote this week, dont know how true

last week diver was wearing one of the new electric shark repellents and it was doing a good job or keeping off a mako that was buzzing him while on deco, it wouldn't come closer than 4m, but was clearly agitated

As the diver reached the boat and started to climb the ladder, the shark leaped from the water and chomped on a leg!!!!!

The transmitted signal didn't work in air!!! and was just irritating the shark

This come from a fairly reputable source and was said to be a UK diver on Hols. Will see if it appears in the official BSAC incident log

 

[donacheson]

Originally posted by magic_johnson
Let me start off by saying I am a newbie, which means I have to rely on my LDS and this site for info. I was looking into a hoseless AI computer (Vytec), and my LDS said he would never dive with one. His reasoning was that the transmitter emits an electrical signal that could attract sharks. Since I'm on the West Coast, great whites are around. He mentioned that he was on a dive, and one of the other divers was attacked by a shark (and lived!!), and that he was wearing a wireless transmitter unit.

Is there any truth to this? I don't have any reason to doubt him since he will gladly sell me the more expensive unit with the transmitter. Has anyone else heard of this?, or have any experience with it? I just want all of the concerns answered before my purchase.

Thanks,

magic_johnson
Go Lakers!!!!!

The disadvantage of an air-integrated computers, hoseless or not, is that the functions of a pressure gauge and ordinary dive computer are combined. If either function fails, one is faced with the cost of replacing both.

On the other hand, an air-integrated computer offers the advantage of being able to compute one's surface air consumption rate, a quantity very useful for dive planning.

As for attracting sharks, I don't know, but I'm rather skeptical.

 

[swedish diver]

to start with, a few fact about sharks (I've got a friend who is marine biologist - with specieallity on sharks and rays... he is my source, and I doubt he talks rubbish : ) ).

Sharks have an organ to sense flux in the electric field surrounding them. Experiments in tanks have shown that sharks attack living fish dug into the sand on the bottom (not very surprising). More surprising: they attack devices emitting elecric pulses into the water, especieally if the electric pulses follow the heart-pattern of the fish!!!

Even very weak currents are enough to attract their attention. However, I do not think an AI, or any other computer would play a significant role. Our pulse is probably more than enough to attract the attention of the sharks. But most likely they will not attac, since they (in contrast with what many of you out there tend to think) are not stupid animals. Most sharks realize that we are not their "natural food". Really hungry or pissed-off sharks could attac... but NOT BECAUSE OF THE COMPUTER.

Btw: why dont you get a wrist mounted one without the AI function. SPG's are more reliable (my opinion and experience). Also, having a console is bulky...

/Kristian

 

[madmole]

Here is the full SP on the shark attack while wearing an electric repellant

from Divenet:

SCALLOP DIVER KILLED BY SHARK
Paul Buckland, a 23-year-old scallop diver, was killed by a shark while being helped back aboard his boat by a friend in the fishing port of Smoky Bay, 310 miles north-west of Adelaide, Australia.
Buckland was diving from a boat anchored in the bay. He surfaced from the dive and uttered a cry for help. His friend tried to help him back into the boat, but a 6m long white pointer shark grabbed his body and pulled him back underwater.
Buckland was wearing an electronic shark-repellant device commonly used by commercial fisherman. A spokesman for the Adelaide-based company making the devices said that once it is out of the water, it can no longer transmit a signal that would repel a shark.
Fishermen in the Smoky Bay area are calling for the shark to be killed, but officials at the South Australia Fisheries Dept have ruled this out because the shark is a protected species.
The killing is the fifth fatal shark attack to take place in Australian waters since 1998.

Guess thats one gadget I wont be buying!!!!

 

[Narced]

Sorry to laugh at something that resulted ina fatality, but you gotta hand it to that shark. I have also heard of electrical devices possibly irritating/provoking sharks, but not with a comp. I have heard several times that many photographers turn their strobe off if a shark appears annoyed or displays unfriendly body language,
anyone ever heard of any fact or truth surrounding this one?

 

[Scubaroo]

There's more to the Australian incident than what was in the article madmole posted from Divenet. The shark in question was a mature (6m = ~20ft) female great white, which had aggressively been harassing fishing boats in the area for about 2 months. The sharkpod in use was a previous model that is no longer in production.

My theory is that the sharkpod just agitated a very large known rogue shark. The sharkpod probably works fine on smaller specimens. Just like one prod from an electric cattle prod will send a yearling running through the gate, using one on a bull is asking for a broken kneecap.

Back to the AI computer - not wading into the arguments for and against them, but if you do get one, keeping your existing SPG as a backup is not a bad idea. You'll be gaining the advantages of the "integration", but no reduction in equipment.

 

[Hal Iotis]

Ok, trying my hardest to pull this thread back out of the sandbox, I'd like to tell you about my paraplegic buddy whom I accompanied on his OW certification dives. The LDS sold him a buncha "vital" equipment, including a $700 Oceanic Data Trans computer. The sales pitch was that it eliminated a hose...

First problem: I, his buddy, can't read his tank pressure due to the fact that the numbers are on his wrist, facing him. Plus his hands move more than the typical diver, due to the fact that he needs them for mobility. Second problem: Can't get computer to read pressure after tank switch. Hmm....Instructor can't figure out, either. Oh well, only a shallow and short checkout dive, no need to know your tank pressure, right???

After much fiddling, the computer works again, now it doesn't, oh, now it does, but the pressure is wrong. Oops, there it goes again. Dang!

I went back to the LDS with him and had 'em swap out the hoseless/AI with an SPG and vyper. Also had 'em console mount the compass (it's hard to read when swimming with your hands...). He ended up with a $79 credit, plus a much more useful setup. Still wish they hadn't sold him the BC octo thingy, either.

It's bad enough to sell this junk to every newby that walks through the door, it's quite another to sell it to someone in a wheelchair, whose rig may require just a little more thought.