Diving to over 500 ft?

[Dive-aholic]

Friend told me last night he thought a woman dove to over 500 feet (free diving.. no scuba gear). I don't know much about the sport but that seemed really deep, though I know it must be different since you aren't breathing air during the ascent/descent.

Anyway, does anyone know if this is accurate?

A little aside - the depth record on compressed air (21%) scuba is 490 feet (although my information may be a little outdated). On mixed gas, it's over 1200 feet. They were breathing during descent and ascent.

 

[Crush-Depth]

The deepest dive I can find on mixed gas is 1044' or 318.25m. Unless someone has gone deeper since June 15th this year.

http://www.divernet.com/news/stories/150605gomes.shtml

 

[MSilvia]

A little aside - the depth record on compressed air (21%) scuba is 490 feet (although my information may be a little outdated). On mixed gas, it's over 1200 feet. They were breathing during descent and ascent.

If my quick math is right, that's a ppO2 of 3.33... roughly twice the oxygen partial pressure that's considered a maximum safe limit. If that depth is true, the diver is lucky to have survived it without succumbing to nervous system toxicity.

IMHO, that dive is far more stupid than brave... sort of like trying to set a record for how far you can fall without a parachute and live.

 

[O2BBubbleFree]

If my quick math is right, that's a ppO2 of 3.33...

Just curious, but the linked article didn't list his mixes. What did you use for your calculations?

 

[gangrel441]

Just curious, but the linked article didn't list his mixes. What did you use for your calculations?

I believe he was referring to 490 ft on compressed air (21%), as stated in the previous post.

 

[Dive-aholic]

If my quick math is right, that's a ppO2 of 3.33... roughly twice the oxygen partial pressure that's considered a maximum safe limit. If that depth is true, the diver is lucky to have survived it without succumbing to nervous system toxicity.

IMHO, that dive is far more stupid than brave... sort of like trying to set a record for how far you can fall without a parachute and live.

You're right. The dive was done by Bret Gilliam in the early 90s. It was done after several acclimation dives to depths over 300 feet. You can read about it in his book, Deep Diving. He explains what he went through to get ready for that dive. After reading that, I don't know if it was a matter of being stupid or brave. It was simply something he did.


I'll have to find where I read about the OC depth record. I could be wrong, but I though I read 1245'.