Exactly how deep is "Deep Air?"

[PfcAJ]

Why wasn't the dive aborted sooner? Couldn't have been because the first gas he was at put him an a high END, could it? Narcosis alone is never the killer, its always that plus something else. Every time. But all the deep deaths have something in common, and that's a high END. I don't see where the mystery is in this. Clear head = better ability to make proper judgments.

I think Sheck was an amazing person who contributed a lot to the sport. Unfortunately, seeking a record did him in, and we all lost something because of that. He was a true innovator, explorer, and a very skilled diver. I can only imagine where diving would be now, if we hadn't lost him.

 

[Superlyte27]

So glad I live in a free country, albeit maybe only temporarily

 

[gcbryan]

I've always said the same thing: Deep air (to include high ENDs) is a bad idea. And irregardless isn't a word

Superlyte, I found this on the IUCRR website "Both Bowden and Exley selected a bottom mixthat would produce a tolerable PO2 of less than 2.0 atm and an equivalent narcosis depth (END, the equivalent depth on air) of 274f/84 m at 970 f/298 m. These levels were accepted by both diverssince the exposure to maximum depth would be brief (not that a higherPO2 would minimize the lengthy decompression at the cost ofincreasing the risk of CNS oxygen toxicity."

So you got me, the END was closer to 300', not 400'. My bad.

Mixthat, diverssince, and offincreasing aren't words, spaces are important, there would be less incomprehension if spaces were always properly used.

 

[PfcAJ]

If I had wrote that, then I'd agree with you. Notice the quotes. I'm not the IUCRR's editor, guy.

 

[shoredivr]

well he is on the deep air death list...
just sayin'

No. While Sheck Exley did dive deep air in caves, sources refer to his use of mixed gasses for deeper and record dives after 1987.

"After participating in the successful 1987 Wakulla Spring project using a heliox mix that had caused no decompression problems among the 12 divers using it, Exley decided that heliox was at least part of the equation for success." pg 320, The Cave Divers, Robert Burgess.

In 1988-9 Exley and Ned DeLoach explored Mante spring in Mexico, where several record dives were made, including one to 867 feet. On a work-up dive to 780 feet, for example, he used 11 different mixes of gases, including trimix, with 52 decompression stops, the first one beginning at 520 ft, with a run time of 10 hours, 43 min.

"Since he felt he had a high oxygen tolerance, he planned to use trimix during the deepest part of his dive. He hoped this would let him avoid certain uncomfortable side effects of diving deep on heliox - extreme cold and nervous system disorders" pg 324

The deep dive that he died on, in 1994 in Zacaton Spring, Mexico, his depth gauge read 904 ft, and mixed gases were also used.