So I just got my nitrox cert. and I have a newbie question

[C Monkey]

I'm planing a dive trip to the Philippines and will be doing a lot of repetitive diving. It's likely I'll be doing 4 dives a day. My bottom times are shorter than other divers, since I consume my air faster. As a result, I'm consuming 150 bar on each consecutive dive.

So my question is this. Wouldn't it be beneficial to use nitrox on every dive as an added precaution to avoid the risk of exceeding my NDL? Or would the oxygen consumption become a factor? If so is there a method of striking a balance?

 

[WarrenZ]

I use Nitrox wherever it is available however as long as you are doing recreational profiles and not pushing PPO2 to the max then it shouldnt be a problem.

Since you are using air at a more rapid rate than the other divers in your group you may not be limited by NDL at all however nitrox will give you a longer NDL so you can stay further from the NDL limits and thus be more conservative deco wise.

 

[C Monkey]

Thanks for replying Warren.

 

[WarrenZ]

No worries I usually dive nitrox when I can as I was on a livaboard and we were all doing 70-90 minute dives on air almost every dive on the second day I hit a couple minutes of deco and ended up with the skin bends due to letting myself get overheated and dehydrated. It was very worry some when it is happening to you and you are away from any major medical facilities (air evac) Fortunately I was ok with some water O2 and plenty of rest and beer however since then I am much more conservative and make sure I stay hydrated.

Moral of the story to you: DRINK WATER

 

[Stoo]

There are really two ways to use "recreational" nitrox. The first, and I think what you're asking, is to breathe Nitrox, but follow a dive profile which presumes you are breathing air.

For example, a typical first dive of the day might be to 100'. The maximum bottom time you can run without "violating" your NDL will be "x minutes" (I use "x" because this will vary depending on the table/computer you are using.) If you were breathing say EANx 32, then that NDL would be pushed back to maybe "x + 30% or so... again, depending on the deco algorithm you are using, and other factors.

The net effect is that you now have a very healthy and conservative profile using the 32 as a buffer. So the short answer to your question is "yes"... breathe it if you can, but be aware of the MOD (Max Operating Depth) as it will be significantly shallower than the MOD of air.

The second way to use nitrox, (And let me say this so there is no confusion!) is to use to extend your bottom time by "pushing back" that NDL.

This method would not be advocated for a newer diver.

I hope this helps~

 

[C Monkey]

Thanks for sharing that Warren. I can only imagine such a circumstance, which Is why I want to do everything within my ability to minimize risk.

 

[C Monkey]

There are really two ways to use "recreational" nitrox. The first, and I think what you're asking, is to breathe Nitrox, but follow a dive profile which presumes you are breathing air.

For example, a typical first dive of the day might be to 100'. The maximum bottom time you can run without "violating" your NDL will be "x minutes" (I use "x" because this will vary depending on the table/computer you are using.) If you were breathing say EANx 32, then that NDL would be pushed back to maybe "x + 30% or so... again, depending on the deco algorithm you are using, and other factors.

The net effect is that you now have a very healthy and conservative profile using the 32 as a buffer. So the short answer to your question is "yes"... breathe it if you can, but be aware of the MOD (Max Operating Depth) as it will be significantly shallower than the MOD of air.

The second way to use nitrox, (And let me say this so there is no confusion!) is to use to extend your bottom time by "pushing back" that NDL.

This method would not be advocated for a newer diver.

I hope this helps~

All very helpful. Thanks

I assume the dive operator will follow a plan that is conservative, but I'd like to get my head around this as much as possible. Having only taken a test on it, leaves a lot to the imagination.

 

[Stoo]

No dive operator is going to fault you for diving "conservatively", as long as it isn't some dive (the Blue Hole in Belize comes to mind) where the DM really wants the group to stick together until the end of the dive.

It's unfortunate that you feel that there is "a lot" being left to your imagination! The point in taking a course is so that you understand how to do something correctly. Perhaps you should be having this conversation with the Instructor, because it sounds like his/her work may not be complete~ ;-)

 

[PhatD1ver]

I'm planing a dive trip to the Philippines and will be doing a lot of repetitive diving. It's likely I'll be doing 4 dives a day. My bottom times are shorter than other divers, since I consume my air faster. As a result, I'm consuming 150 bar on each consecutive dive.

So my question is this. Wouldn't it be beneficial to use nitrox on every dive as an added precaution to avoid the risk of exceeding my NDL? Or would the oxygen consumption become a factor? If so is there a method of striking a balance?

From my experience (diving in the Philippines on EAN) the biggest benefit you will get from it is the way you feel at the end of the day. The first time I was in Anilao, I did 10 dives over 2 days (4 & 6) and each day I was dragging, getting up the stairs from the dining room to my room was a challenge. The next time I went a couple months later, I had my EAN and after my first dive on air, all the other dives (8) (over 2 days) were on each EAN dives, and I was full of energy afterward.

I know that everyone says that the evidence is anecdotal that EAN prevents fatigue and helps with after dive recovery, but I'll swear by it.

If you are chugging down the gas at this point, then this is the only real benefit you can expect. Short of extending your bottom time on a deep dive (with properly matched EAN) with a pretty direct decent and ascent profile, you'll just get the benefit of less N2 in your system overall on multiple dives.

 

[Patoux01]

The first, and I think what you're asking, is to breathe Nitrox, but follow a dive profile which presumes you are breathing air.

And this is perfect to have no trace of either CNS or N2 load.

The second way to use nitrox, (And let me say this so there is no confusion!) is to use to extend your bottom time by "pushing back" that NDL.
This method would not be advocated for a newer diver.

Funny, because that's the only thing nitrox does, reduce the on-gassing of N2. What the diver does with that afterwards has nothing to do with being a beginner or not.


The result of nitrox is a reduced N2 load for a given dive (compared to air) or a longer dive for the same N2 load (again comparing to air).

Nitrox is almost always beneficial to use. I'd personally use nitrox on all dives...

All this should have been covered in your nitrox course though...