what the different between using Nitrox and Normal Air to dive???

[Rich Keller]

Blindly following anything is the worst thing you can do, no one really knows how Oxygen toxicity occurs no one really knows how decompression works, and that includes the US navy, so you educate yourself, be a thinking diver and make your decisons.

One thing to consider, how many dives a year do you think US navy divers make a year in total, how many dives do divers from the main rec/tech agencies make a year? Hell I'd be willing to bet the divers on this board make more dives a year than the US navy do.

I have no idea how many hours the average Navy diver spends in the water but I would beat the ones at the NEDU are putting in a lot more hours a year then anyone else you have mentioned. As for blindly following anything, I never made that statement, that was PfcAJ trying to put words in my mouth!

 

[PfcAJ]

Blindly following the US Navy Diving Manual is the worst thing I could do????? Are you suggesting you know more and better then they do????? All you know is what you have been told by other people as arrogant as you seem to be. I will stick with what the Navy has to say!

Orly?

 

[Rich Keller]

Orly?

Sticking with the Navy recommendations is not the same as blindly following. That again is you putting a spin on something I have said. Again I am quoting the Navy on their use of nitrox not stating my opinion. But I do value their opinions far more then yours.

 

[PfcAJ]

All I've asked since we started this little game is "why do you feel the way you do? Do you have some science to back it up?"

The only answer you've gave me is "because the navy manual says so and thats what I did with commercial diving."

So what? They do it, so you do it, too?

btw, your responses were intentionally paraphrased to not waste time.

 

[Ana]

The Navy is doing the research and using the science that applies. They also read all the other research that is out there. Go to the Panama City facility and you will see they are doing a lot more then just "a fair bit of research". They are also talking to more qualified people then just sport divers!

Yes they are doing much much more than just "a fair bit of research". Tests related to human divers are just a portion of what they do, they put all kinds of things under pressure.. and yes they know their stuff, I don't think anyone is arguing that.

But seriously, maybe I lost track of your argument (old fart disease)... are you saying rec divers should not use NITROX? or just that instructors should do additional tests to students?

Because if it is that NITROX is not safe for rec divers, that ship already sailed.

 

[Elvistheking]

I have no idea how many hours the average Navy diver spends in the water but I would beat the ones at the NEDU are putting in a lot more hours a year then anyone else you have mentioned. As for blindly following anything, I never made that statement, that was PfcAJ trying to put words in my mouth!

So you honestly think that the divers at NEDU spend more hours in the water in total than the WHOLE of the rec/tech community combined, I think you need to stop doing that deep air, it's seriously getting to you!

 

[Rich Keller]

Yes they are doing much much more than just "a fair bit of research". Tests related to human divers are just a portion of what they do, they put all kinds of things under pressure.. and yes they know their stuff, I don't think anyone is arguing that.

But seriously, maybe I lost track of your argument (old fart disease)... are you saying rec divers should not use NITROX? or just that instructors should do additional tests to students?

Because if it is that NITROX is not safe for rec divers, that ship already sailed.

My original question at the start of this is was there an oxygen tolerance test being done before starting a nitrox class. From that point on I have just quoted the Navy on nitrox use. In my opinion it is fine for the purpose it was intended and that was for use at shallow water decompression stops. The deeper you go from there the more risk you open yourself up to so that test seems like an easy precaution for anyone using it below 50'.

 

[PfcAJ]

To which myself and others replied with science that shows the futility of oxygen tolerance testing (still haven't read those studies, have you) and DAN recommendations on recreational Nitrox used (did you skip that one, too?).

Le sigh...

 

[boulderjohn]

Sticking with the Navy recommendations is not the same as blindly following. That again is you putting a spin on something I have said. Again I am quoting the Navy on their use of nitrox not stating my opinion. But I do value their opinions far more then yours.

As for sticking to Navy recommendations, the only support you have for that is a private phone conversation to which no one else in the world was privy.

As I said before, I don't see anything in the Navy manual itself that supports your point of view. Everything I see there is consistent with what is taught in recreational nitrox instruction. If I missed it, please show me.

The one part that is different from normal recreational trimix use is the part that says its primary benefit is above 50 feet. That may be true for Navy hard hat divers cleaning boat hulls (or other such work) for hours on end, but it is not true for recreational diving. Recreational dives that shallow have longer NDLs on air than almost anyone dives, so most recreational divers normally think it is a waste of money at that depth and don't start using it until at least 60 feet. The PADI table NDL for 32% nitrox at 45 feet is nearly 4 hours.

As for scuba on trimix, my last dive was to 261 feet for 20 minutes of bottom time. I used a mix of 15% O2 and 55% helium on the bottom and 21% O2 and 35% helium during the middle part of my ascent. You say that was a waste. Do you think I should have done that dive on air?

 

[chokolad]

It is well established that ppO2 1.4 or lower does not cause statistically significant number of CNS toxicity cases. Recreational Nitrox is used below that threshold, or at least Nitrox classes teach you that. EANx 32 is about as safe as air from tox point of view below 100 feet and has significant benefits from a lower percentage of Nitrogen in it.

As for why not use trimix at these depths - some people do. It's just too expensive and does not really provide any significant benefits for the price.