How did old-school deep air divers avoid ox tox hits?

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Indeed, and thanks to those who posted their experiences. Quality!
 
Danvolker is right on the money in post 5.

The Navy and commerical divers were given O2 tolerance tests which gave an idea of general tolerance to higher P02. It was risky because what they were really getting was their tolerance on that day. When these guys left the service/job some continued to dive and knew their "limits" others learned from those guys and found their own limits such as Danvolker posted " and the rest never felt good below 200." I'm going back further than the 90's here, my perspective startes back in the 70's, before Nitrox and trimix was common to sport divers.

The test was done in a chamber at 60' for 30 minutes on 100% O2.
 
And this can all evolve into the present issue with Nitrox use.....We like it to be able to do 2 dives on a 2 tank dive boat trip, without a huge surface interval, that the boat won't be able to give you if they want to run 2 or 3 trips per day--if they want to attempt to run like a real business :)

Air just makes this impossible or lame, in places like Palm Beach. We use the high O2 mixes because the bubbles in our blood we want to avoid, are the bigger evil....the lesser evil is the damage from free radicals high oxygen content will stimulate. We take vitamin C and E and other anti-oxidants, to remove as many free radicals as we can all day long, every day, to enhance health, to prevent aging somewhat, and to aid in recovery from workouts....lots of 36 % mixes day after day, will be doing exactly the opposite of what we take vitamins for.

And at the Blue Heron Bridge Marine Park, where many divers will use Nitrox, just because they use it all the time...if they dive multiple days per week, 3 and 3 hour long dives, they can get hyperoxic myopia from the high oxygen mix....Howard Hall got it this way once in Indonesia or some place on that side of the world, as has my wife wife Sandra at the BHB.
 
I’m confused. I have never been around a sat with PPO2s above 0.8 ATA in the water, usually more like 0.3. Granted, it’s been a while since I was offshore but why bother unless you are running crazy deep excursions (diving well below the saturation holding depth in the deck chamber)? Deep bounce dives with a small bell system is another matter but I didn’t think much of that was done anymore.

Barfing in a hat is a good reason to pull a diver even if they are in 30' on air. Burping often gets the mask yanked, at least for 10-30 minutes. All the barfing in hats I have witnessed had more to do with excessive Tabasco on breakfast or the previous night’s celebration than gas mixes.

---------- Post added May 16th, 2012 at 10:12 AM ----------



Are any military or commercial diving schools still running Oxygen Toxicity tests? I heard the US Navy stopped years ago concluding they were not very predictive of individual sensitivity. It is ironic that they would test you before going into sat since Sur-D-O2 usually exposes divers to far higher risks.

Personally I am glad I did the test for the self-confidence factor… but it was only my second chamber ride so it was still fun at that point.


Ha ha ha ... not Ox Tox ... maybe BH will illuminate us with further details of what his toxicity was due to ... you can probably guess.

Oxygen toxicity tests were commonly run on Indian commercial divers heading to deep bounce or sat until the early '90's.
They have not been conducted as routine anymore, although we do test thresholds on divers occasionally.
 
Ha ha ha ... not Ox Tox ... maybe BH will illuminate us with further details of what his toxicity was due to ... you can probably guess.

It was the Haggis ...
 
Snake, good thread, great replies.

I asked a similar question when I began learning deco procedures. We were planning deco gasses and stops which pushed oxygen pressures well above 1.6 atm. My instructor answered that we should be relaxed and not working while holding the stops, and that this allowed higher ppO2.

A few years later I came across an SB post by Dr. Deco (see this thread) which says, in part:

The time to convulsion in turn is modified by the partial pressure of carbon dioxide, a vasodilator. When a diver is in the water and breathing elevated oxygen pressures, the activity of the diver is contributing to the production of CO2. An accumulation of CO2 has been found to influence the time to convulsion.
 
Great replies indeed! Very educational =D
 
The Britannic dives as I recall were with triples and quads 72s/80s filled with different blends. Once below 10th most blends are safe. Low O2 requires around 100ft and then it is safe
 
The Britannic dives as I recall were with triples and quads 72s/80s filled with different blends. Once below 10th most blends are safe. Low O2 requires around 100ft and then it is safe

That must have been quite a trick with only one double hose regulator attached to those tanks.
 
https://www.shearwater.com/products/perdix-ai/

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