Another Great trip- need advice on nitrox cert.

[mjatkins]

Definitely wrong answer. Nitrogen absorption is a function of tissue loading which depends on depth and % of nitrogen in the mix, time, M-values, etc. But air consumption is not a factor. Otherwise men would be more prone to DCS simply because they have bigger lungs. Bigger divers would be more prone than smaller divers. That's just not the case.

Well said. This is a hard one for some people to be convinced of, but you are absolutely right. If PSI/bar of air consumed had influence on your nitrogen loading, it would be accounted for in the tables. It is not. All other factors being equal, time and pressure are what dictates our absorption and release of nitrogen. Now, granted not all other things are equal, which is the rational behind basing the tables on a variety of "tissue compartments". Also the reason that it is recommended that we stay well within our limits.

 

[Prop Joe]

I did the referral routine when I did my EAN training. LDS for initial and Mateo Gutierrez at Aldora for my practical/ in water work. Dive physiology fascinates me so Mateo and I had some great talks at the surface intervals while training and in the following years diving with him. I think, even if you not dive nitrox, you can benefit from the knowledge gained during the training. This EAN training will serve you well in the remainder of your diving activities. EAN and the rescue diver course in my mind is the most beneficial of all of the "ratings/cards" offered.

Edit: My LDS mixes their own gas with their own equipment. As a mechanic at heart and loving all things mechanical, the blending is another fascinating thing for me to see in person and test various mixes. If you can, I'd recommend going to a fill station and seeing how the mixing is done and test various mixes of gas. I've watched them mix at the LDS and even lent a hand occasionally. Cool stuff!!!

 

[ggunn]

But i knew the dull pain in my side was the first sign in sept. and i didn't know what it was and kept diving and thats when it hit the fan-lol be back in june to try it again. thanks for tips and advice.

I am in no sense encouraging you to take on more risk, but just because two things happened at the same time (or close to it) doesn't necessarily mean that they had anything to do with each other.

 

[Mossman]

Well said. This is a hard one for some people to be convinced of, but you are absolutely right. If PSI/bar of air consumed had influence on your nitrogen loading, it would be accounted for in the tables. It is not. All other factors being equal, time and pressure are what dictates our absorption and release of nitrogen. Now, granted not all other things are equal, which is the rational behind basing the tables on a variety of "tissue compartments". Also the reason that it is recommended that we stay well within our limits.

Honestly I like the European system better, where all diving is treated as deco diving. "Optional" safety stops are silly, if you can't do the time, you shouldn't do the crime. If agencies "enforced" a mandatory stop, buoyancy control would necessarily improve and exceeding one's NDLs wouldn't sound so scary.

 

[Tigerman]

Honestly I like the European system better, where all diving is treated as deco diving. "Optional" safety stops are silly, if you can't do the time, you shouldn't do the crime. If agencies "enforced" a mandatory stop, buoyancy control would necessarily improve and exceeding one's NDLs wouldn't sound so scary.

Except thats not a "european" system. Some agencies maybe, but recreational and deco diving are very different things here as well as in the US and theres no mandatory safety stops thats enforced "in europe"..

 

[Ron Lee]

Honestly I like the European system better, where all diving is treated as deco diving.

Was it a Pyle guy who stressed the deep stops? Making the ascent a multi-level event seems to make far for sense than a direct ascent to the safety stop.

The analogy may not be physiologically accurate, but I equate it to shaking a coke can and opening quickly or very slowly. Which is less messy?

 

[Brules]

No Gastric bypass DD- just lots of exercise and atkins diet. Just got back monday and back to the gym twice a day. ugh, but totally worth it.

A couple of people have posted using regular computer with nitrox? Can i do that? My computer doesn't do nitrox and i was going to rent one for june and buy one later. I am not looking for longer bottom times , i just think (and i know it's not proven) that it may help me since i seen to be maybe more susceptable to DS than some.

I dive nitrox on air on my computer and it is a no issue. I like it as it is safer and I don't feel as tired after several days of diving. I don't (majority of coz divers dont either) use it for longer NDL's. My computer is an older Oceanic VT Pro and works great. Buy a used one off of here and get a great deal on a computer.

 

[DandyDon]

I dive nitrox on air on my computer and it is a no issue. I like it as it is safer...

There's that myth yet again. :silly: It's been covered here, but keeps coming back - still, it can't hurt within reasonable MODs. I once saw a couple of divers who had booked Nitrox for their second dives only handed their Nitrox by mistake for the first, deeper dive. Only when they ask for O2 analyzers for their second tanks was it discovered and they were a little shook.

The second dive at Coz may be so shallow that even then Nitrox has a negligible effect. It varies. One time the whole boat had booked Nitrox for second dives, and we enjoyed the first dive so much, we just did it again on Nitrox.

Whatever - it's a good tool to have and use when you want to.

 

[Mossman]

Was it a Pyle guy who stressed the deep stops? Making the ascent a multi-level event seems to make far for sense than a direct ascent to the safety stop.

The analogy may not be physiologically accurate, but I equate it to shaking a coke can and opening quickly or very slowly. Which is less messy?

I believe that's why they call them "Pyle" stops

It was never battered into my head, as it should have been, that the last 15' or so of ascent is the most important and should be done by inches if possible. Then I saw a very seasoned (and old) diver literally inching his way up the line in Belize and I realized gee, that makes a lot of sense. I love my Suunto, it totally enforces a one-minute deep stop and as far as I know, that's kept me from being being. Or at least it's enabled my hard drinking. Maybe that's not such a good thing.

 

[halocline]

Honestly I like the European system better, where all diving is treated as deco diving. "Optional" safety stops are silly, if you can't do the time, you shouldn't do the crime. If agencies "enforced" a mandatory stop, buoyancy control would necessarily improve and exceeding one's NDLs wouldn't sound so scary.

Except for one small detail, the entire concept of recreational diving is based on the assumption that if a problem develops you have immediate access to the surface. Having 'mandatory' stops negates that assumption.

There is a practical qualitative difference between diving in situations in which you can safely ascend immediately to the surface and situations where you cannot. So, IMO, diving in such a way that there are mandatory stops is not practical recreational diving.

Regarding the 'additional safety' of nitrox, the two sides of the coin-both correct- are that A) all other things equal, less N2 loading 'should' result in less risk of DCS. That's an assumption, but based on widely accepted ideas about DCS. B) In order to absolutely state that a given practice presents less risk than another, statistical evidence is a necessity, and to date there are no statistics supporting it.

I suspect some dive physicians recommend divers who have demonstrated risk for DCS (like by getting it!) to use nitrox on air tables because they believe that it's at least theoretically beneficial. I personally would not use an air computer with nitrox, particularly with lots of repetitive dives. I want to track O2 exposure as well.

If I were in the OP's situation, I would study the basics of decompression theory and learn as much as is practical about DCS and dive behavior that appears to be associated with it. I would do very long safety stops, and I would conduct dive profiles in such a way as to minimize N2 exposure. I really believe that knowledge is important in this case, and that good understanding of the basic models can result in more intelligent dive behavior, which in turn is likely to be the best safety practice.