100% 02 during your SI?

[Thalassamania]

Dan I like you but this is a bit cavalier....

Even a diver with good buoyancy shouldn't be doing this without appropriate training. What if they go OOA at depth and switch to the "pony" bottle? What if they add a second slung bottle and now they are doing gas switches at depth without knowing the gas switch procedure--if they've been carrying one bottle for years, then carrying two bottles shouldn't be a big deal, right? What if they don't mark it appropriately and someone on the boat mistakes it for their stage?

Recreational nitrox certifies you to 40% mixes. Much better idea to use those mixes you've been trained in to try to make your safety stop safer.

What if their grandmother had two wheels? Why ... she'd be a bicycle!

Carrying one slung bottle and knowing enough to not use it below 20 feet does not impress me as complex enough to warrant a course.

 

[DevonDiver]

Dan I like you but this is a bit cavalier....

Yes, I was always led to believe that ox-tox was the biggest killer of technical divers. I think the average tech diver would count as 'advanced', at least in the respect that they've been trained and tested on their buoyancy.. and intimately understand the relationship between ppO2, depth and toxicity.

Yes, an 'advanced' diver could do it... but it's a hell of a risk to take, without some external assessment to confirm that your suppositions about being 'advanced' are correct. Holding a decent stop 99 out of 100 times, just doesn't cut the mustard when breathing 100%.

 

[Captain12Pk]

I'm sorry, but this kind of ... Just go ahead and do it, you don't need training... advice is going to get someone hurt or worse.
In water gas switches can be dangerous.

Ulfheddin, if you decide this is a path you want to pursue, please do yourself a favor and get some adequate training. Feel free to contact me anytime. I'll happily steer you in the right direction and/or help you train. Don't get youself hurt based on (IMO)borderline reckless internet advice.

Happy diving,
K

As Thal said, if ypu want the extra margin, buy a 20 or 30 cu ft pony bottle, get it cleaned and filled with O2, and carry it stage style like GUE divers ( clipped to left side cheast D-ring and waist d-ring) with it's own reg on it and short hose, looped and held close to the tank by a bungee or similar...View attachment 108614
you don't need one this big though unless doing technical exposures

There is NOTHING to doing this....The pre-requisite is that you must have good bouyancy skills, and be able to hold your 20 foot stop depth within 5 feet, no matter what. As this is incredibly easy for an advanced diver ( if it is NOT easy, the person is NOT an advanced diver !!!!!) , this is a great solution for you.
And 10 minutes is the right amount of time...much longer and you begin to get a form of edema from the o2 exposure......
Keep this in mind also.....O2 has a side effect..it is much healthier than to get large bubbles in your blood, and to get DCS....But if you are NOT in danger of DCS, pure oxygen, and even Nitrox at 30 to 40 % mixes, is essentially increasing the amount of free radicals your body is exposed to enormously--this is what we take Vitamin C and Vitamin E, etc, to eliminate, due to the unhealthy nature of free radicals in your body.

So pushing ther maximum oxygen exposure you can handle without toxing is not the smartest thing you could be doing

 

[Captain12Pk]

And what if this guy toxes and drowns because you told him you didn't think he (who you've probably never met, let alone been in the water with) needed any deco. training?

What if their grandmother had two wheels? Why ... she'd be a bicycle!

Carrying one slung bottle and knowing enough to not use it below 20 feet does not impress me as complex enough to warrant a course.

 

[LiteHedded]

I'm sorry, but this kind of ... Just go ahead and do it, you don't need training... advice is going to get someone hurt or worse.
In water gas switches can be dangerous.

Ulfheddin, if you decide this is a path you want to pursue, please do yourself a favor and get some adequate training. Feel free to contact me anytime. I'll happily steer you in the right direction and/or help you train. Don't get youself hurt based on (IMO)borderline reckless internet advice.

Happy diving,
K

nothing borderline about it. oxygen will kill you quicker than anything in diving.

 

[ErikH]

nothing borderline about it. oxygen will kill you quicker than anything in diving.

Anything? Really? How about having nothing to breath at all?

But indeed, please consider training before playing around with stages and high ppO2 mixes.
DAN has some nasty statistics on gas switches gone wrong..

 

[Akimbo]

nothing borderline about it. oxygen will kill you quicker than anything in diving.

Actually anoxic or hypoxic blackout from breathing a very lean O2 mix or pure diluent is much faster, virtually instantaneous. Simple hypoxia/drowning is probably next unless you are taking about O2 at 600'.

 

[LiteHedded]

threads like this are why I steer clear of the advanced forum. I will leave you gentlemen to it.

 

[Thalassamania]

I suppose that I may be over estimating the ability of divers who reach the point where they have the sophistication to start thinking about accelerated deco, in which case I'd suggest that you fix that problem rather than just throw another course on top of what must, clearly, be a depauperate training scheme.

Perhaps it is just chance that those who are jumping up and down about the need for such divers to take a course that will teach them to hold a 20 foot stop and help them adjust to the complexity of removing a regulator from their mouth and inserting a different one, are folks who either make their living by flogging such courses, or have a wallet full of cards that proclaim their ability to perform such difficult tasks. Perhaps that's an honest judgement based on the students that they see and the folks that they tend to dive with, divers who know that they lack the skill and knowledge to perfom such feats of daring-do and thus seek out the sort of training situation that they proffer or recommend who would never dream of opening a book on the subject or approaching a more experienced friend. To me, the whole thing reeks of the kind of BS that the NITROX industry was founded on, but then I guess that's 'cause I see a better class of diver because I don't dive resorts or cattle boats.

 

[danvolker]

Yes, I was always led to believe that ox-tox was the biggest killer of technical divers. I think the average tech diver would count as 'advanced', at least in the respect that they've been trained and tested on their buoyancy.. and intimately understand the relationship between ppO2, depth and toxicity.

Yes, an 'advanced' diver could do it... but it's a hell of a risk to take, without some external assessment to confirm that your suppositions about being 'advanced' are correct. Holding a decent stop 99 out of 100 times, just doesn't cut the mustard when breathing 100%.

In technical diving, we are talking about a gas switch at maybe a depth of 100 feet, and their maybe 3 different choices of gases to choose from--this IS technical diving....


The issue discussed here, is someone going from air or nitrox, to O2 at 20 feet....not at 100 feet. So if the "advanced" diver misses his O2 reg, and somehow breathes out of his alternate 2nd, his worst case scenario is breathing the air or Nitrox...not so much of a killer with this one..

The "switch" is at 20 feet, so danger of getting pure o2 accidentally does not exist. If the issuse being brought up is the advanced diver ended up solo, which he should not have, then ran OOA, which he should not have, what happens if he grabs the O2 reg at 100 feet deep, because he is afraid to try a free ascent from 100 to 30 prior to making the switch....and even here, while I am not advocating anyone should ever do this on purpose, a diver about to drown due to their own stupidity of running OOA, AND not having the skill to do a free ascent from 100 to 20 feet, "could" go on 100% at 100 feet, and then begin a full speed bouyant ascent to 20 feet, where they would hold the stop for 10 minutes....this is more desirable then them spitting the reg and drowning at 100 feet....and more likely for them to survive.... In most of the tech deaths I have heard of where a tech diver grabbed pure O2 at 100 feet, they breathed it for MANY minutes, sometimes over ten minutes, prior to an oxtox event....the idea of surviving 30 seconds without having an oxtox episode is feasible, from 100 feet to 20 feet...... But to be clear, my advice was NOT to have divers use an O2 tank as a bailout for poor gas management, to go on at a 100 foot depth. My advice was to an advanced diver that could hold a stop within 5 feet ( which is easy)....and just for cleaning his nitrogen levels out at a 20 foot depth....not even for a deco stop...but as a safety stop. I do NOT advocate solo diving, so this diver WOULD have a buddy with them, and no excuse to go on the pure O2 at 100 feet--no excuse to go OOA.