1997 Deep Dive/Shark Attack.

[logan brown]

So two guys try to reach 500 ft depth on air, end up dead... and sharks get blamed for it?

That was a mistake on the report, my family was very very close to Mac. He was breathing nitrox

 

[OTF]

That was a mistake on the report, my family was very very close to Mac. He was breathing nitrox

Nitrox would actually be far more dangerous (and stupider) to use on a 500ft dive. Maybe you meant trimix? If you actually know the exact gas mix(es) he used, or other details of the what the hell really happened in this wild tale, please consider sharing that information. It could help set the record straight, and understanding what happened in any accident will help other people dive more safely in the future.

 

[yle]

That was a mistake on the report, my family was very very close to Mac. He was breathing nitrox

At that depth, nitrox vs air doesn't matter. Anyone that knows even the basics of diving understands this.

I'm still curious as to how sharks are to blame for their poor decisions.

 

[yle]

Nitrox would actually be far more dangerous (and stupider) to use on a 500ft dive. Maybe you meant trimix?

I'll suggest that it's highly unlikely they obtained trimix and then chose to skip making a proper plan to 500 ft.

Here's why:

1. To use trimix, they would have to know what mix to choose.

2. To know which mix to choose, they would have to have the relevant training.

3. If they had the relevant training, they would have understood the dire importance of a proper plan.

Point 3 is evidently false, so the logic chain collapses.

 

[Mark IV]

At that depth, nitrox vs air doesn't matter. Anyone that knows even the basics of diving understands this.

.
Actually, nitrox vs air makes a HUGE difference. Not to dismiss the obvious and serious risk, but the world record for breathing air on scuba, is over 500ft, and has been since the 90s. In fact, when I was working in cozumel years ago, I was actively working towards beating Bret Gilliams (then) record ( of around 450 then 480, IIRC), and have been well below 400 ft, several times, and several friends have also been nearly as deep. We routinely did air dives below 300.
Nitrox on the other hand would have guaranteed fatalities, well before reaching those depths, so nitrox vs air would have made a highly significant difference.
(And before anyone predictably dog piles on me, those were different times, and we were all admittedly young and foolish, and lucky to have emerged unscathed. So, I'm not endorsing deep air diving, just using my experience to make a point.)

 

[OTF]

.
Actually, nitrox vs air makes a HUGE difference. Not to dismiss the obvious and serious risk, but the world record for breathing air on scuba, is over 500ft, and has been since the 90s. In fact, when I was working in cozumel years ago, I was actively working towards beating Bret Gilliams (then) record, and have been well below 400 ft, several times, and several friends have also been nearly as deep.
Nitrox on the other hand would have guaranteed fatalities, well before reaching those depths, so nitrox vs air would have made a highly significant difference.

It's important to note that while nitrox definitely is worse than air on those deep dives, even on air you were vastly exceeding the recommended MOD, breathing a dangerously high PO2 and battling narcosis that would severely impede anyone.

 

[boulderjohn]

A few years ago, I had a private conversation with Brett Gilliam, and part of the conversation included his deep air diving. He was specifically talking about the deep air dives he did with Sheck Exley, also famous for setting deep diving records. Incredibly enough, Brett told me that Sheck used to black out at times while diving deep on air. He would quite literally pass out for a while, wake up, and then go on diving. He said he believed that explained the strange circumstances of Sheck's death. Sheck was found intentionally tied off to his descent line, and Brett thought he might have realized he was about to pass out and tied himself off so he could resume the dive when he woke up. Brett felt that his passing out was a reaction to narcosis. I'm not so sure.

A number of years ago in Cozumel, Opal Cohen, owner of Scuba Mau, died following a deep air dive. The most common version of the story was that she was so narked at 300 feet that she continued to descend to 400 feet before she was caught and turned around by her divemaster. When I went to Cozumel shortly after that, a DM told me that she had actually passed out during the dive, which would be similar to what Brett described with Sheck Exley.

I wonder if passing out at such depths could be a toxic reaction to the high PPO2 rather than narcosis. Either way, it is clear that some people will pass out at those depths while diving on air. If so, it would not be a good thing when it happens.

 

[OTF]

That's fascinating and terrifying. Wish we had better data, but I would assume that oxtox and narcosis are both capable of causing blackouts.

Either way, passed out is no way to be when the alleged shark comes at you.

 

[boulderjohn]

Either way, passed out is no way to be when the alleged shark comes at you.

And neither is dead by drowning after passing out.

Of all the fish in the sea, the most common one is the one divers rarely see--a dead fish. Animals that die in the ocean usually get eaten pretty quickly.

Notice that the diver had bites on him when he was found, but that's it. He had not been fully eaten. When I went to Maui more than a decade ago, just before I arrived, a snorkeler had been bitten on the thigh by a tiger shark. He managed to get to shore with the help of other snorkelers who then successfully provided first aid. While they were working on him, the chunk of his thigh that had been bitten off floated in. The shark had apparently spit it out.

A year or two ago, divers ascending at the end of the dive in Socorro were harassed by a tiger shark, and as they reached the surface, the shark attacked one and inflicted a fatal bite. I have been paying attention to these stories for a long time, and it is the only one I know in which a shark attacked a diver that it had identified as "not prey" at depth, with the exception of spearfishers or others with captured fish. It could indeed be possible that a shark made an investigative bite that proved fatal on this man, but I would sincerely doubt it made fatal investigative bites on both of them.

 

[ChuckP]

And neither is dead by drowning after passing out.

Of all the fish in the sea, the most common one is the one divers rarely see--a dead fish. Animals that die in the ocean usually get eaten pretty quickly.

Notice that the diver had bites on him when he was found, but that's it. He had not been fully eaten. When I went to Maui more than a decade ago, just before I arrived, a snorkeler had been bitten on the thigh by a tiger shark. He managed to get to shore with the help of other snorkelers who then successfully provided first aid. While they were working on him, the chunk of his thigh that had been bitten off floated in. The shark had apparently spit it out.

A year or two ago, divers ascending at the end of the dive in Socorro were harassed by a tiger shark, and as they reached the surface, the shark attacked one and inflicted a fatal bite. I have been paying attention to these stories for a long time, and it is the only one I know in which a shark attacked a diver that it had identified as "not prey" at depth, with the exception of spearfishers or others with captured fish. It could indeed be possible that a shark made an investigative bite that proved fatal on this man, but I would sincerely doubt it made fatal investigative bites on both of them.

So now you got me fidgity about going to Socorro - thanks John LOL