Can I take my Nitrox with my open water class?

[adventurelarry]

I don't know if I'll ever be a deep diver, but was just wanting to increase my dive time. Thanks!

 

[--tom--]

I think the Nitrox addition to your OW is a good idea. Sometimes the nitrogen loading on your body is from an imperfect dive profile (a sawtooth profile), rather than purely depth/time. This profile is more common with a new(ish) diver. Nitrox does NOT provide a "free pass", but it would add an additional margin for error in case of less than flawless bouyancy control. As always, YMMV.

BTW, congrats & have fun!

 

[Sinbad the Diver]

I think there are two parts to that....can you, which is being discussed here already, and will a shop let you? I don't know the answer to the first, but I do wonder if any op will do your checkout dives on Nitrox. It's out of the ordinary and I suspect most ops would look at you a little cockeyed and say "we don't do that". If you are alone, that would be one thing, if there are multiple people on your checkout dives I doubt the isntructor will want to deal with divers on air and divers on nitrox when as was stated, you realy don't get any advantage at checkout dive depths.

 

[Tailspin]

Sinbad the Diver is right in that some shops (or instructors) may not want you to use Nitrox for OW certification dives.

I recently completed my Rescue Diver certification and some of the participants were Nitrox certified, and others not. The instructor wouldn't allow Nitrox during the dives because of the share air scenarios (something you also do in OW dives). He didn't want a non-Nitrox certified diver sharing air with a Nitrox diver, even for that short interval to the surface.

It seemed really anal to me, but it was his call so we all used air that weekend.

 

[Sinbad the Diver]

I don't know if I'll ever be a deep diver, but was just wanting to increase my dive time. Thanks!

At the depth you'll be diving during your checkouts, you are going to run out of gas a long time before you reach NDL. At 40 ft you have 140 mins of NDL time on the PADI table, you are probably looking at 30 - 35 mins max air time on an al80 (amazing how fast you suck down air during those first few dives). Plus, if you are in a group, bottom time is driven by the most powerful hoover in the group..

I think it's a fine idea, I just wouldn't spend any time worrying about using Nitrox on checkouts since it realy won't buy you anything.

 

[Splash-X]

AdventureLarry,

You could get Nitrox certed which will add to your knowledge which is always good but I think in the short term you should perhaps just use air on your dives. Why?

a) Your OW cert (assuming PADI) limits you to 18m and the benefits of nitrox start to kick in at deeper depths than this

b) Using Nitrox sets a Maximum Operating Depth which you should not exceed. This early in your dive career you need to dive a bit and practice the new skills you'll have learned in your class. Buoyancy control is one of those skills and making sure you are in control of your depth at all times is important but becomes even more important with Nitrox so that you don't exceed the MOD.

Are you forgetting the other use of Nitrox? As a added margin of safety? Using Nitrox while observing the standard Air tables (or leaving your computer on 20%) gives you a large margin to avoid DI. You still have to observe the MOD for your mix, but using a 32% mix greatly reduces your risk for DI.


To the OP, there are many shops in my area that will allow you to dive your first dive on standard air and do your final checkout dive on Nitrox (providing you took the Nitrox class).

 

[Damselfish]

Even if you can do Nitrox during your OW class, I don't think you should. You will have plenty of information to digest and practice already. And having just gotten certified, Nitrox is highly unlikely to increase your bottom time. Nitrox increases your bottom time only when you run out of gas before time, which is almost unheard of in a new diver. It's true that even a new diver doing many multi-level dives a day at certain depths might manage to hit their NDLs, but I'm guessing you won't be doing that in Florida. (Occasionally someone gets the mistaken idea less gas is used when using Nitrox; in case you're thinking that it's not the case.) As far as safety, you will absorb less nitrogen and that's always good, but you are not "greatly reducing" your risk because the risk is already extremely small, especially on the dives you'll be doing.

If you want, get your OW squared away, and take the Nitrox class if you want to do a little more studying on vacation. Or take the class when you get home. For most basic Nitrox classes dives are no longer required and don't teach you anything more. Sometimes people combine Nitrox with AOW, which I think makes more sense than trying to glue it onto OW.

 

[dbulmer]

Splash-X,
Damselfish more or less said what I would have replied but I'll go further.

An even better way way to get the added safety factor is for the OP to concentrate on dive planning (planning both NDL and gas consumption), improving buoyancy control, avoiding multiple repetitive dives and having fun on dives is more beneficial in the long run.

 

[Damselfish]

One other thing - if you're out to increase your bottom time, the best way to do that now is to concentrate on developing good buoyancy control and just dive. The better you have nailed down the basic skills and the more comfortable you are in the water, the less air you will use. It's a process every new diver goes through.

 

[Splash-X]

An even better way way to get the added safety factor is for the OP to concentrate on dive planning (planning both NDL and gas consumption), improving buoyancy control, avoiding multiple repetitive dives and having fun on dives is more beneficial in the long run.

Gas consumption has nothing to do with using Nitrox over air over Trimix. I agree that gaining the necessary skills and getting comfortable will reduce your SAC rate and increase the time your tank will last.

I still have to disagree about the saftey. What is the contributing factor for NDL? When your tissue is saturated with Nitrogen. Would you not agree that breathing 80% nitrogen for 30 minutes vs 68% for the same time, same person, same depth will result in LESS nitrogen absorbed? It doesn't matter if you drain your entire tank in 30 minutes or only half the tank, less nitrogen is still less nitrogen.

There are two primary reasons to dive Nitrox

1.) To increase your bottom time by reducing the amount of Nitrogen absorbed by increasing the amount of O2 in the tank.

2.) To use as a saftey margin, diving air tables or computer set to "air" and diving a mix of Nitrox as if it were air. Assuming your body is exposed to 80% nitrogen when in reality only 68% on EAN32 greatly adds padding to the NDL




Not everyone uses Nitrox for the same reasons. Just because one person may use it to extend bottom time doesn't mean that your buddy does.