nitrox ?

[peter]

Hi how are you all? I have been diving for about 5yrs and have only ever used air. My question is can you tell me if nitrox is as good as i hear it is. I have heard that you feel much better after a dive not so draggy. But on the down side not any good for deeper dives below 20 mtrs. Have you tried it and would you say it was worth doing a course.Any info would be helpfull. Thanks

 

[BillP]

Hi peter:

Personally, I think that a good nitrox course is worth it whether you dive nitrox or not. The knowledge you gain about different gas mixes and their effect on diving and decompression will help you better understand dive planning for air as well as nitrox dives.

Nitrox has several advantages. If you find that your dive times are being limited by the no decompression limits (rather than surfacing because you're low on air) reducing the nitrogen in your breathing mix can extend your bottom time. If you do not dive nitrox to the no decompression limits, you will absorb less nitrogen and reduce your risk of DCS somewhat. Some people do report feeling better when diving nitrox as you suggest. You can dive nitrox to the typical recreational limits of 130ft/40m if you select the right mix.

Nitrox has its disadvantages also. Divers on air don't have to be concerned about the possibility of oxygen toxicity within typical recreational limits, but it can be a major concern on nitrox. Cost is a factor too. The course can be expensive, most dive operations charge extra for nitrox fills, and there may be additional equipment costs involved. (You'll frequently see people recommend no special equipment cleaning if your equipment only sees nitrox with 40% O2 or less, but depending on the filling method you still might have to have your cylinders O2 cleaned, buy and maintain your own nitrox analyzer, maybe buy a nitrox dive computer to take full advantage of the increased NDL's, etc.)

I think that a nitrox course was worth it to me, and I recommend taking one.

HTH,

Bill

 

[Dr Deco]

Peter:

I thank BillP for some thoughts on this subject. I myself have only dived with air and thus can not offer any personal observations.

In certain cases, where decompression is a consideration, nitrox can be a real answer. At NASA, we use it for the astronauts in the large "weightlessness" training pool (Neutral Buoyancy Laboratory). Without this gas, a very expensive decompression facility and much valuable time would have been needed. While the cost of adding all of the pumps and lines was considerable, it never began to match the cost for the decompression facilities.

If you dive nowhere near the no decompression limits, most likely you would not see a benefit in overall DCS reduction, since most divers never encounter a case of DCS in the diving careers – fortunately!!

Many divers have indeed noted a reduction in fatigue. The reason for this is unclear although it has been postulated as related to a reduction in subclinical gas bubble formation. Fatigue following decompression is a question we follow at NASA but do not yet have an answer. [This was discussed a little in another posting called "the Voodoo Gas Effect."]

 

[peter]

Many thanks to Dr D and Billy P. It is not often that I would go any where near the deco limits. There's no point in having to spend a lot of bottom time because everything is so compact where we dive here in sunny Queensland. It was more the comfort factor I was interested in. I also sheep dog for an instructor mate which means I can surface many times in a single dive to help out wayward learners. I still haven't made up my mind whether or not to try nitrox but I will read up on it.The dollar side is not a factor as we have a dive operator mate who has all the nitrox gear for hire. He is based in northern New South Wales we only ever dive with him for pleasure never when training students.Although I like helping and highly recomend to anybody to help out not in a teaching capacity (I leave that to the pro's)it can be quite a taxing way to spend the afternoon. Sort of like looking after a lations kids. You can go from strangle mode to laughing mode in a second.You'd be surprised just how much you learn from other peoples mistakes and how many people make the same mistake. Thank you both for your imput will read up on voodoo gas effect. Many thanks Peter

 

[SubMariner]

Peter, BillP & Dr.D have said most of what needs to be said.

We resisted going Nitrox for a number of years. Okay, so a couple of them were spent aboard a sailboat in the Bahamas with no access to Nitrox, but why get picky?

This year, however, we started diving Nitrox and are finding it quite beneficial... mostly for the those reasons already outlined by our learned friends.

Meanwhile, as Instructors we sometimes do as many as 5 training dives per day. With Nitrox we seem to find ourselves less tired. This despite the fact that many of the dives are done in cooler waters in drysuits. Is this a "placebo effect"? Unsure. I only know that it used to be after *3* dives with students I'd be toast. Now...

The only "negative" to this was while on vacation in Bonaire last month I was unable to find nitrox HP steels. So I had to use a regular AL 80 with a din/yoke adaptor.

DSDO,

~SubMariner~