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-   -   Open Your Mouth, And You're Dead (http://cellar.org/showthread.php?t=26884)

Gravdigr 02-15-2012 03:17 PM

Open Your Mouth, And You're Dead
 
I tripped across this article concerning the 2011 Free Diving World Championships.

It's a long article, but, I think, well worth your time. Very interesting.

These guys (and girls) are nuts if you ask me.

Open Your Mouth, And You're Dead, from outsideonline.com.

Quote:

“Blow on her face!” yells a man swimming next to her. Another man grabs her head from behind and pushes her chin out of the water. “Breathe!” he yells. Someone from the deck of a boat yells for oxygen. “Breathe!” the man repeats. But Kitahama, who just surfaced from a breath-hold dive 180 feet below the surface of the ocean, doesn’t breathe. She doesn’t move. Kitahama looks dead.

Moments later, she coughs, jerks, twitches her shoulders, flutters her lips. Her face softens as she comes to. “I was swimming and…” She laughs and continues. “Then I just started dreaming!” Two men slowly float her over to an oxygen tank sitting on a raft. While she recovers behind a surgical mask, another freediver takes her place and prepares to plunge even deeper
:headshake

BigV 02-15-2012 03:20 PM

"...possibly crazy..."

That editor sucks. Or they need better fact-checkers.

infinite monkey 02-15-2012 03:23 PM

No way. You have two things against you there: nitrogen narcosis and compression. Oh, and breathing.

You can't just shoot to the top. They didn't say anything about decompression. If you're not using equipment you can't stop at the intervals needed so you don't, like, die.

I call poppycock. ;)

http://en.wikipedia.org/wiki/Deep_diving

Quote:

Amongst technical divers, there are certain elite divers who participate in ultra-deep diving on SCUBA (using closed circuit rebreathers and heliox) below 660 feet (200 m). Ultra-deep diving requires extraordinarily high levels of training, experience, fitness and surface support. Only eight (or possibly nine) persons are known to have ever dived below a depth of 800 feet (240 m) on self contained breathing apparatus recreationally.[8][9][nb 6][10] That is fewer than the number of people who have walked on the surface of the moon. The Holy Grail of deep SCUBA diving was the 1,000 ft (300 m) mark, first achieved by John Bennett in 2001, and has only been achieved five times since. Dives of this nature have been impossible to verify - proof being as tangible as faith more often than not. Since the recent introduction of depth gauges capable of reading to 330m it is unlikely that such records will be attempted in the future.

In 2003 Mark Ellyatt claimed dives to depths of 260m and 313m.
Quote:

Dealing with depth
Technical divers preparing for a mixed-gas decompression dive in Bohol, Philippines. Note the backplate and wing setup with sidemounted stage tanks containing EAN50 (left side) and pure oxygen (right side).Divers carry larger volumes of breathing gas to compensate for the increased gas consumption and decompression stops.
Rebreathers manage gas much more efficiently than open circuit scuba, but are inherently more complex than open circuit scuba.
Use of helium-based breathing gases such as trimix reduces nitrogen narcosis and stays below the limits of oxygen toxicity.
A diving shot, a decompression trapeze or a decompression buoy can help divers return to their surface safety cover at the end of a dive.
Deep Diving Depth[nb 1] Comments
40 feet/12 metres Recreational diving limit for divers aged under 12 years old and beginner divers.
60 feet/18 metres Recreational diving limit for divers with Open Water certification but without greater training and experience.
100 feet/30 metres Recommended recreational diving limit for divers.[1] Average depth at which nitrogen narcosis symptoms begin to appear in adults.
130 feet/40 metres Absolute recreational diving limit for divers specified by Recreational Scuba Training Council (RSTC)
Maximum depth reachable by a French level 2 diver accompanied by an instructor (level 4 diver), breathing air.

180 feet/55 metres Technical diving limit for "extended range" dives breathing air to a maximum ppO2 of 1.4 ATA.
200 feet/60 metres Maximum depth reachable by a French level 3 diver accompanied by another level 3 diver, breathing air.
218 feet/65 metres Depth at which compressed air results in an unacceptable risk of oxygen toxicity.
330 feet/100 metres Technical diving training limit for divers breathing trimix. Recommended technical diving limit.
509 feet/155 metres Record depth for scuba dive on compressed air.
660 feet/200 metres Absolute limit for surface light penetration sufficient for plant growth, though minimal visibility possible farther down1,083 feet/330 metres World record for deepest dive on SCUBA
2,000 feet/610 metres Navy diver in Atmospheric Diving System (ADS) suit

BigV 02-15-2012 03:34 PM

Quote:

Originally Posted by infinite monkey (Post 795511)
No way. You have two things against you there: nitrogen narcosis and compression.

You can't just shoot to the top. They didn't say anything about decompression.

I call poppycock. ;)

Both of those worries are not risks. Since you're breathing air at only one atmosphere of pressure, no matter how deeply you dive, upon your depressurization as you approach (hopefully!!!) and reach the surface, there is no gas in solution that wasn't already in solution when you took that breath. Therefore no "bends" or decompression sickness. As for nitrogen narcosis, the same reasoning applies, you are only taking one lungful of nitrogen laden air, something you've done countless thousands of times already. It isn't possible to saturate yourself with nitrogen starting with sea level air pressure and ending with sea level air pressure.

Dangers? Sure. Hyperventilation is a big one. That's when you essentially blow off the carbon dioxide to below the normal level during normal respiration. It's the presence of CO2 that gives you the urge to take a breath. By artificially changing that level, you "trick" your body into thinking you don't need to take a breath. Yeah, these folks are nutzo.

glatt 02-15-2012 03:34 PM

But this isn't SCUBA. They take a breath of air, and go down, it's compressed, and when they come back up it expands to the size it was originally.

With SCUBA, you breathe compressed air down below, and you come up fast, and it expands and you burst.

EDIT: what V said

infinite monkey 02-15-2012 03:35 PM

I don't believe it, that's what I'm saying.

glatt 02-15-2012 03:37 PM

What I have trouble wrapping my head around is swimming that distance on one breath. Going down, sure. Swimming back up? How?

infinite monkey 02-15-2012 03:42 PM

We took a can coolie to 110 feet. It was roughly as big around as a pencil at that level.

So these folks are wanting to go to 800 feet? Oh, film it, I'd love to see a body cave in on itself.

BigV 02-15-2012 03:59 PM

Quote:

Originally Posted by glatt (Post 795518)
What I have trouble wrapping my head around is swimming that distance on one breath. Going down, sure. Swimming back up? How?

I've gone 300 feet in one breath.

Back in the day, yeah. Horizontally. On the surface. At swim practice that was cool/fun, but not especially superhero. Four laps and make it snappy!

BigV 02-15-2012 04:02 PM

Quote:

Originally Posted by infinite monkey (Post 795521)
We took a can coolie to 110 feet. It was roughly as big around as a pencil at that level.

So these folks are wanting to go to 800 feet? Oh, film it, I'd love to see a body cave in on itself.

like one of those neoprene sleeves that keep your beer cold? Mostly air, right? Well your body is mostly incompressible water. Your lungs, hell yeah, but they're designed to compress, like on and exhale. But I agree with you, that must feel like being crushed.

Beest 02-15-2012 04:24 PM

When you're at depth the air in your lungs is at the same pressure as the surrounding water. If you're breath holding from the surface the air is still pressurised , it just reduces in volume, the risk of narcosis and bends are the same.
It takes time for nitrogen to be absorbed into tissues, just as it takes time for them to be released, the time spent at depth is very small, so the bends are unlikely. I don't rememeber if narcosis is also time related but I rememeber them saying it's something you can get accustomed to, like drinking.

Only the air spaces in the body are subject to volume change, at 300m you lungs would be 1/30 th the size !

I skimmed the article and didn't find any reference to "open your mouth and your dead', maybe it's in the video, but since pressure it equalized it shouldn't matter if you open your mouth.

wolf 02-15-2012 04:28 PM

Has anyone else seen The Big Blue?

footfootfoot 02-15-2012 04:56 PM

Quote:

Originally Posted by BigV (Post 795509)
"...possibly crazy..."

Yes, if by "possibly" you mean "beyond the shadow of a doubt"

Quote:

Kitahama, a female competitor from Japan
I rest my case, your honor.

infinite monkey 02-15-2012 04:57 PM

WACKY

Gravdigr 02-15-2012 05:01 PM

Quote:

Originally Posted by infinite monkey (Post 795511)

Quote:

Originally Posted by infinite monkey (Post 795517)
I don't believe it, that's what I'm saying.

Well, since you obviously trust Wikipedia...

Free Diving


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