diving air to 210 feet??

[diverrick]

Last nght at the 4th of July fireworks show, my wife and I met this guy who insisted he had dove to 210 feet on air only, using doubles, and he stayed down for 15 mins at 210 feet. He said they did some deco stops on the way up, and then hung at 10 feet for a long time breathing pure O2 from a manifold fed from he ship.

I have my doubts as to the voracity of his claims. Is it even possable to go to 210 feet on air?? I would think that bad things would happen at those depths. What do you guys think?

 

[Dr Deco]

Hi Diverrick:

Yes, you can go to 200 fsw on air- unreliably. Mentation is poor, and the US Navy introduced helium as a gas in the mid 1920s.

 

[fdog]

I will admit that I have done this, although the profile was 205 fsw for 10 minutes. This was back in the late 70's; we thought we were pretty high-tech back then, because we used doubles, had hung safety cylinders and were very conservative with the stops.

There were three of us; we each had a very simple, single task for the dive. I had to attach and screw the shackle closed, one guy was just to keep track of time, and the third was to make sure we two were doing our jobs. We were so narced this was task-capacity for us.

Looking back I wouldn't do it again, but at the time, we were pretty proud of doing it in what was a (for the era) safe and thoughtful manner.


All the best, James

 

[The Surly Mermaid]

Yes, it's possible. Before the introduction of Trimix, anyone doing deep diving beyond the recreational limits had to be on air. What the guy at the fire works show described is generally what happens if you dive that deep on air. Short bottom time, several deco stops and O2 at 10 feet. When diving that deep on air Narcosis can be a serious issue to safety. Plus, at depths deeper than 218 feet you have to start worrying about Oxgen toxicity. But the short answer is yes, it can, and has, been done.

 

[ianr33]

Why O2 at ten feet ???

And I would start worrying about O2 toxicity before 218 feet (pO2 of 1.6ATM)

 

[The Surly Mermaid]

Why O2 at ten feet ???

And I would start worrying about O2 toxicity before 218 feet (pO2 of 1.6ATM)

They (notice I don't say I... I'm not a tech diver, I don't even play one on TV) get the O2 at ten feet because 100% O2 becomes toxic at roughly 20 feet.

 

[Tomeck]

Yes, it is possible. Cousteau dove at 100 meters (330 feet) with air.

 

[DandyDon]

Saw a stunt dive once, totally surprised me! Lead instructor in our foursome started going down, we all followed - I stopped when my Nitrox hit 1.6, the two laides hovered a bit deeper, he vanished, I'm wondering how narced I am to be seeing this? He did a bounce to 256, to best of his narced knowledge. I still dive with him, trained more with him since - but I was pissed then and have watched him closely since. It was really out of character for him; I dunno? Younger superman type, and he was hurting some but wouldn't talk about it - skipped the next dive, the last one of the trip. He got bent another time since, as well as hurt on a construction accident that cost him a few operations and I think has calmed down significantly. He's on his way to Utila today as group leader.

This thead talks about the deepest air dives recorded to more than 500 ft: http://www.scubaboard.com/forums/basic-scuba-discussions/86520-deepest-scuba-dive-air.html

 

[ppo2_diver]

I'd be more concerned with CO2 toxicity in addition to narcosis and Ox tox.

 

[orange_diver]

They (notice I don't say I... I'm not a tech diver, I don't even play one on TV) get the O2 at ten feet because 100% O2 becomes toxic at roughly 20 feet.

100% O2 is not toxic at 20', in fact that is the perfect depth for it to be used as a deco gas as you have a 1.6 PO2.