Diving Nitrox to increase safety AND bottom time!

[fjpatrum]

But you have at least tried/experienced it to be able to make any sort of informed decision as to whether or not you may want to use it in the future - THAT is my point!

I knew whether I had an interest in using Nitrox long before I got the cert. It's why I took the class in the first place. Similarly, I knew I wanted to get Scuba certified long before I actually dove. I didn't need to "have the experience" to recognize the desire or benefits in either case.

We each assess things differently though. I think we're going to have to agree to disagree on this issue as we just think differently about it.

 

[beaverdivers]

Hey just because some agencies set the bar low in certain areas (all are guilty of something...) doesn't mean the instructors or dive shops should follow suit. I usually role this into another class that requires diving. Knock 2 birds out with 1 stone.

Isn't it against most training agency standards to count a dive towards more than one class ( cert. )?


What skill(s) do you require while diving for your nitrox cert. class?

 

[fjpatrum]

Well if my theory holds true then it does have a bearing on how you feel at-least on that second dive, less tired. That is of course, a feeling is it not? I think it has more bearing then you actually know now and even less after you dive Nitrox 250+ days a year... Relevant yes, but really this debate has be done on a daily basis since it was endorsed for recreational use back in 1992... Its like arguing about how wet your going to get out side based on the rate of rain droplets counted by 2 people with different methods... Its a mute point, go dive and have some fun!

So because you used Nitrox on a previous dive and are less tired you can somehow tell you're using Nitrox on a consecutive dive? I don't think so. Regardless of how many dives you do or don't do on Nitrox, you can not tell, on any individual dive, what gas you're breathing without analyzing the tank.

That's the point of the whole side discussion. You can't tell what gas you're breathing just by breathing it so there isn't any need to do a dive in order to get the Nitrox cert. It feels the same as breathing air and the only practical knowledge of the course is how to analyze a tank.

 

[vladimir]

But you have at least tried/experienced it to be able to make any sort of informed decision as to whether or not you may want to use it in the future - THAT is my point!

I should just drop this, but I can't help myself. Could you explain the practical difference between trying nitrox during a course, or after the course? Let's say you get certified online, and then, on your next dive, you dive nitrox! How would that be different from trying it during your course?

If you think the demonstration of testing procedures and the in-person classroom instruction would be valuable to you, I totally understand that. Why is breathing nitrox during the course valuable?

 

[Phil_C]

I ended up taking the TDI course to get a better theoretical background (all the others teach computers and TDI teaches tables) but still had to go into my local shop to analyze a tank before I got my card..

I must have got the best of both worlds then - I did a PADI course a month or two back - OK no dives, but covered computers, dive tables, manual calculation of oxygens depths, oxygen toxicity exposure and so on, and gave me a manual, workbook, PADI tables and DVD. But I only got wet walking from the car to the classroom in the rain - P

 

[TjRjn]

That's the point of the whole side discussion. You can't tell what gas you're breathing just by breathing it so there isn't any need to do a dive in order to get the Nitrox cert. It feels the same as breathing air and the only practical knowledge of the course is how to analyze a tank.

See this is what I'm not getting. Different people have told me they have better outcomes when diving with nitrox ie. no headaches, less tired, more alert etc... So regardless of how it 'feels' at the time is it not beneficial to try it to see what effects (if any) it has on you as an individual rather than just studying it in the classroom?

 

[redacted]

I should just drop this, but I can't help myself. Could you explain the practical difference between trying nitrox during a course, or after the course? Let's say you get certified online, and then, on your next dive, you dive nitrox! How would that be different from trying it during your course?

If you think the demonstration of testing procedures and the in-person classroom instruction would be valuable to you, I totally understand that.

Easy answer s the trainer will not be able to charge as much. I can see absolutely no sense in paying extra for a nitrox dive just to be able to experience nitrox.

 

[Zen Diving Inc.]

Isn't it against most training agency standards to count a dive towards more than one class ( cert. )?


What skill(s) do you require while diving for your nitrox cert. class?

Against most training agency standards.... I don't know why don't you look mine up.

Since there are no dives required for this certification, what standard is being violated?

I just said that I usually role this into another class, so I can physically show them how to use a few different types of O2 analyzers. Then we go over EAD again in real life between dives. Dive with the table, dive with the computer etc... Works well in an advanced class. And is by no means a training violation.

 

[vladimir]

See this is what I'm not getting. Different people have told me they have better outcomes when diving with nitrox ie. no headaches, less tired, more alert etc... So regardless of how it 'feels' at the time is it not beneficial to try it to see what effects (if any) it has on you as an individual rather than just studying it in the classroom?

You can breathe it all you want after the class!!

 

[doctormike]

Statements like this is why I've come to be so detached from the formal instruction model of learning. Professionals making decisions based upon whimsy. Why not teach students all the facts and let them decide how they will use the gas.

Actually, the decision not to teach the commonly held assumption that nitrox reduces the rate of undeserved hits is not based on whimsy, but rather a reluctance to present a reasonable but unproven theory as fact.

EAN reduces the amount of N you uptake. That is a fact.

I agree

This can either be used to extend BT (which negates the DCS safety buffer) or to provide a DCS safety buffer. That is a fact.

I do not agree.

While it may provide a buffer in the sense that if you dive nitrox while using air tables and blow past your NDL inadvertently, you would still be within non-deco range, I am not aware of research that shows a lower rate of undeserved hits in this situation. Of course, the problem is that undeserved hits are rare, so to really draw a scientific conclusion about that, you would need to accumulate profiles on huge numbers of dives in order to get enough of these events to see if they were less common with EAN than with air. Making such a study even harder to do is the fact that you would need to match cases with controls - you would have to find divers with similar profiles but different mixes who had a UDH.

This is one of the reasons why it's hard to do good science in the realm of diving physiology. To find strong evidence that a drug works in humans, the gold standard is to do a prospective, double blind study where you randomized similar patients to two groups, and assess outcomes without knowing which group got which treatment. The more uncommon the outcome that you are looking for, the bigger the group you need to achieve statistical significance, even if you are doing a lesser study (like the retrospective case series that you would do in studying DCS).