Error 130 dives on Fake Nitrox

[FishWatcher747]

Yep, this is my first symptom.
I DM'ed for a while with a shop that did dives on the west coast of Oahu to a wreck at 90 ft. The dives were all on air. Most of the dives were to my NDL, often working harder than I'd like to get don't-dive-very-often-customers up to the safety stop and then doing air-sharing on the hang bar. Second dive on a modest reef, not deep, not near NDL. I was often exhausted after the two dives, and sometime would have to pull off the road and snooze as I drove home. I don't feel that way on 90-ft dives anymore, but now I don't use air, I stay away from NDL, and I now dive 70/85 instead of my old Oceanic GF 95 (approx).

The operative phrase appears to be stay away from NDL. The other stuff not so much.

 

[Stoo]

Not sure you've understood the situation. This diver never thought they were using Nitrox, never analysed a tank or had anyone analyse it for them. They knew they were on air, just the computer was misconfigured all along.

No, I understand it. Analyzing your gas and then confirming that your computer settings match what the analysis read, is one process. Entering the water without 100% certainty of what you're breathing (and frankly, what your buddy is breathing) is a recipe for trouble, sooner or later. In this example, their profiles appear to have ended up in shallow water for an extended period, which was all "decompression". That's the nice thing about tropical reef diving... a lot of the time, the decompression just "happens" by virtue of finishing the dive noodling around in the shallows.

And with all due respect, in your comment that I quoted, they didn't actually "know" what they were breathing, because they didn't analyze their gas. They "believed" they were breathing air, because someone else told them that they were breathing air. Do what you will, but that's not good enough for this boy.

There can be exceptions of course. We're heading to a little place in Belize later this winter and they only have air, so nitrox isn't an option. Obviously, there's no need to analyze those tanks.

 

[tursiops]

The operative phrase appears to be stay away from NDL. The other stuff not so much.

Maybe. The problem is that a GF-Hi of (say) 95 gives you a high NDL to stay away from. You may be better off staying closer to a low GF-Hi, such as what you'd get from GF-Hi of (say) 70.

 

[paddydiver]

Well I had a customer ask me for a 40% Nitrox mix because he wanted to go to 40m......and he was certified!!

 

[Angelo Farina]

Which is my point, they are averages, safe for most but to assume one person diving an algorithm has the same physical response is silly, some people get bent and some (most) don’t with the exact same dive, the computer just runs the program.

Exactly. I think that people trust these electronic devices a bit too much. Your brains is much better, in some respects, and using a computer does not mean that it will take care of everything.

 

[Searcaigh]

Well I had a customer ask me for a 40% Nitrox mix because he wanted to go to 40m......and he was certified!!

Last year a newbie instructor questioned my use of Nitrox because the site we were planning to dive was only 28m

Sooner or later fin manufacturers will start putting R and L on fins to remind people which foot to put them on.

I did once point out jokingly to someone who wore Large fins that they had two Left fins due to the L stamped on them, and they were really confused until I did mention that I was joking

 

[OctopusLover]

No, I understand it. Analyzing your gas and then confirming that your computer settings match what the analysis read, is one process. Entering the water without 100% certainty of what you're breathing (and frankly, what your buddy is breathing) is a recipe for trouble, sooner or later. In this example, their profiles appear to have ended up in shallow water for an extended period, which was all "decompression". That's the nice thing about tropical reef diving... a lot of the time, the decompression just "happens" by virtue of finishing the dive noodling around in the shallows.

And with all due respect, in your comment that I quoted, they didn't actually "know" what they were breathing, because they didn't analyze their gas. They "believed" they were breathing air, because someone else told them that they were breathing air. Do what you will, but that's not good enough for this boy.

There can be exceptions of course. We're heading to a little place in Belize later this winter and they only have air, so nitrox isn't an option. Obviously, there's no need to analyze those tanks.

Well, the issue is unless you have taken a Nitrox course, to my knowledge, no agency teaches even about the existence of such computer settings or Nitrox. You're supposed to be able to be oblivious to it all.

 

[Cthippo]

And this, boys and girls, is EXACTLY why you analyze every tank, every dive. If you're diving nitrox, you should own your own analyzer and you need to take it with you when you travel. That way you don't need to take the DMs word for what you're breathing, and you don't need to wait to use the boat's analyzer that's shared between 16 people.

Tell me you didn't read the first post without telling me you didn't read the first post.

His gas was fine, his computer got set to nitrox without his knowledge and he did 130 dives on air with the nitrox settings.

 

[Allen-1]

Tell me you didn't read the first post without telling me you didn't read the first post.

His gas was fine, his computer got set to nitrox without his knowledge and he did 130 dives on air with the nitrox settings.

i was at CCV a couple years ago. Diving Nitrox (32), and using their Nuvair to check each tank. Don’t know what others did - but that’s what my instructor taught me.

Another diver on my boat went off resort for a shark dive. I talked to him later. He dove air for the sharks, forgot to reset his DC and got bent pretty badly. Didn’t do a necessary deco stop.

He wasn’t young, nor inexperienced- he screwed up - and it cost him.

I added checking my DC gas setting to my pre-dive checklist. I do it when analyzing the gas. Make sure mix is what I expect -and- make sure DC matches.

Seeing him being carried off the launch because he couldn’t use his legs was a very serious reality check.

 

[Stoo]

Maybe. The problem is that a GF-Hi of (say) 95 gives you a high NDL to stay away from. You may be better off staying closer to a low GF-Hi, such as what you'd get from GF-Hi of (say) 70.

Most recreational divers haven’t got a clue what you’re talking about. As per the original post, there was no gas analysis and no appropriate configuration of the computer. Any talk of GFs seems a little “out there” until they figure out the basics.

Tell me you didn't read the first post without telling me you didn't read the first post.

His gas was fine, his computer got set to nitrox without his knowledge and he did 130 dives on air with the nitrox settings.

If your breathing gas is one thing, and you're diving a profile set by your computer which is set to a different gas, nothing is really "fine". The only reason they were "fine" was because they were diving a simple profile that ended up in the shallows. In this case, it doesn't sound like the profile was anything too exciting, but having mismatched gas and computer settings can have all kinds of fun side-effects as you know. Toxing out, getting bent, are all possibilities under the right circumstances.

Anyway apparently you have your way of doing things, and I have mine. My routines have served me well as I come up to 6000 dives.