Two recent articles on Nitrox

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theatis

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I'm starting another thread on Nitrox, not because I'm fixated on the subject, but because I've recently read two articles on it that take decidedly different angles.

In the May 2006 issue of Dive Training there is an article by Alex Brylske entitled "Nitrox: Understanding the 'Dr. Jekyll and Mr. Hyde' Gas". The author is responding to a letter by a new diver who finds it hard to believe that oxygen could actually be poisonous. The author proceeds to explain why that is the case in a (IMHO) objective and informative manner. If there is any bias on the subject, it's a positive one, and the article ends with "I hope that you do take the nitrox course."

Conversely, in the July 2006 issue of Scuba Diving there is an article by John Francis entitled "Magic Gas?" While this article is also informative, I detect a negative undertone. The author dismisses several perceived benefits to the use of Nitrox and then goes on to talk about its actual benefits. Then, according to the author, it turns out that those benefits are also overvalued. Maybe I'm mistaken, but it seems as if the author is trying very hard to dismiss the actual benefits.

Consider the paragraph (first paragraph on p.83) which discusses the increased no-deco times of Nitrox; the author states "how often do you end your dive when you run out of deco time? Do you go directly to the surface even though you have gas left? Or, like most of us, do you ascend until your computer gives you more minutes, use those, then ascend to get some more, riding your no-deco limits until you've used your gas supply?"

There are two problems with that: one, the underhanded compliment 'Nitrox gives you more no-deco time, BUT it doesn't really matter practically' and two, the fact that the above quote comes across as advice! Given the readership of the magazine, which includes many new and impressionable (such as myself) divers, isn't it at least somewhat irresponsible to endorse riding the computer?

There are numerous other examples of the same formulation but I don't want to bore you with an overly long post. I just wanted to bring it up for discussion and to solicit the thoughts of divers more experienced than I.
 
Yes, I remember reading that article in ScubaDiving magazine. I don't remember the details but I DO remember that it was a generaly negative article about NitrOx. I don't recall the statement about riding the computer NDL's. I would have to say that is VERY bad advice. Nitrox does give you longer NDLs for rec limit diving. HOWEVER, you need to have an RMV that is capable of making use of the longer limits for that to be of use (if you dive a single 80). Even if you can't stay on a single tank long enough yet, you can use NitrOx to increase the safety of the dives you currently do.

FD
 
I have read both articles and I think they are both pretty fair and balanced and say about the same thing but from dif. angles. I particularly agreed with the Scuba Diving article though and thought it was dead on. If your dive shop brain washed you into believing that Nitrox ALONE will make you a safer diver so you would take the course, then you might read the SD article as negative. :wink:

I believe the Nitrox advantage to be miniscule, although obviously existant, and DAN's numbers agree. I'll still use it when appropriate and will take any small advantage I can get, even if that advantage is only theoretical. Here is a link to a recent discussion on this same issue here on SB but on another forum. Enjoy!

http://www.scubaboard.com/showthread.php?t=145857
 
The Scuba Diving issue had a couple of other things that I wouldn't have thought much about if I didn't spend WAAAAAY too much time reading ScubaBoard. In two separate featured articles, it shows divers planted on the bottom. In a third article, the monthly accident article, it advises to get positively buoyant when you run into trouble when submerged by dumping weight or other means. Sounds a little dangerous to me. I thought you dump weight on the surface to get positive but doing so at depth could lead to uncontrolled ascent.
 
i have to admit i didnt read any of the articles. it's a pain in the butt to get a dive magazine here in jamaica to begin with (ok, its a lame excuse).
anyway, i regard alex brylske as a very capable diver / instr. / padi cd, even if he (his own words, when we did an dan aed user / instr. course together in 2002) stated that he didnt teach a course in 10yrs. i expect that to be a general statement anyway and would assume he taught the occassional course here or there but not really on a "commercial" level anymore. he is still one of the most experienced instr.'s i know in the industry and (co)wrote a lot of books beside editing divetraining.
i would put in from my side, nitrox is as beneficial or not as you want it to be. does it give you extended bottomtime? - yes it does at the right divesites and assuming a reasonable sac. is it saver than air? - well, that depends on your dive profiles, your age group and many other factors. can you assume it to be safer if you dive airlimits on nitrox? - yes. while divetables are assumed safe by tests, they admit (if you read the small print) that it is in "average and general". usually also more conservative dive profiles are recommended with increasing age. based on that, if you dive nitrox on air limits or slightly exeeding them you should be on the safer side of "maybe" compared to air (makes only logically sense, since your nitrogen load has to be less). if you max nitrox out in any form (be it square profile bottom with tables or multilevel with computer the safetyfactor wont increase but your bottomtime - gas supply permitting), so no - not safer, but yes - benefit of increased divetime as long as your sac plays along assuming a single 80cuf tank or alternatives. so is it inarguably safer? - no! if you max limits (by whatever means and with whatever gas) you increase your risk of the "abnormal" dcs hit. so end of the day, you make any gas you use as safe as your diving habits with it, there is no safe, unsafe or evil. have the needed training to use it and make your decision based onyour needs to get the maximum beneficious factor for yourself out of it!!!
 
scubadobadoo:
I have read both articles and I think they are both pretty fair and balanced and say about the same thing but from dif. angles. I particularly agreed with the Scuba Diving article though and thought it was dead on. If your dive shop brain washed you into believing that Nitrox ALONE will make you a safer diver so you would take the course, then you might read the SD article as negative. :wink:

How things change. When I took my first nitrox course "my diveshop" did have, use or teach niitrox and they weren't too happy about me finding a class to take.

So, I wasn't brainwashed yet I still view the SD article as a bit negative. It also seems to make some real assunptions about the kind of diving people do...ride the computer up? Ever try that on a wreck thats close to a square dive profile? Limited by gas supply? Maybe on the first dive and/or if we assume that all diving is done with a single 80 cuft tank.

More O2 means less N2. Period. How useful that is depends on the dive or the series of dives that are planned.
I believe the Nitrox advantage to be miniscule, although obviously existant, and DAN's numbers agree. I'll still use it when appropriate and will take any small advantage I can get, even if that advantage is only theoretical. Here is a link to a recent discussion on this same issue here on SB but on another forum. Enjoy!

http://www.scubaboard.com/showthread.php?t=145857

The advantage of nitrox, depending on the dive series is demontrably not miniscule.

As far as DAN numbers, we need to know a little more about the sample population. From my own observation of the diving population, I'd say that poor dive habits are prevelant enough to invalidate an alalysis of the effect of using nitrox on the number of DCS incidents. My background with statistics leads me to believe that we're looking at drawing an inference from raw data without seeing any probability calculations or significance testing...again, making the inference invalid.
 
ZzzKing:
The Scuba Diving issue had a couple of other things that I wouldn't have thought much about if I didn't spend WAAAAAY too much time reading ScubaBoard. In two separate featured articles, it shows divers planted on the bottom.

I see that as a general indication of total cluelessness.
In a third article, the monthly accident article, it advises to get positively buoyant when you run into trouble when submerged by dumping weight or other means. Sounds a little dangerous to me. I thought you dump weight on the surface to get positive but doing so at depth could lead to uncontrolled ascent.

Assuming proper weighting you should NEVER need to dump weight at depth to reach the surface. Doing so will, in many cases, result in a rapid uncontrolled ascent, which is dangerous. One might consider that better than sure drowning but it can kill you anyway.

In the past magazines have been fond of pointing out how often divers are found on the bottom with their weights still in place. ok, but they probably had their fins in place too and they did nothing to show a causal effect of either. Divers then run around paroting those rediculous statments made in the magazines and before you know it lots of people believe it. Too many never stop to think that you shouldn't ever be so negative that you can't get yourself to the surface. Of course, they probably don't think of it because so few were taught how to occomplish that or that it's even important.
 
I too read the SD article by John Francis and thought it seemed a bit negative. I think he was just trying to keep everything in perspective, as it seems that ads all over the place are touting the wonders of this magic gas. I usually find the SD articles informative, and was suprised by the negativity.
One thing to remember about DANs numbers: The vast majority of those numbers are coming from live aboard diving, where the conditions are often ideal, someone to help with the gear getting on board, a nice relaxing environment. In the latest numbers I saw all of the DCS hits were from cold dark deep wreck diving. not nice warm comfy live aboards with nitrox or without...
Personally, Ill take every single advantage I can get my gloves on, but then again I dive in cold wreck water...
Airric
 
theatis:
....
Consider the paragraph (first paragraph on p.83) which discusses the increased no-deco times of Nitrox; the author states "how often do you end your dive when you run out of deco time? Do you go directly to the surface even though you have gas left? Or, like most of us, do you ascend until your computer gives you more minutes, use those, then ascend to get some more, riding your no-deco limits until you've used your gas supply?"
...

Odd. The magazine must be aimed at 10 logged dive OW divers or something? (We don't get it this side of the pond so never read it).

A typical nitrox dive for me is 100' wreck. Nothing above the wreck only green sea and 10' vis. Quite what you would do in that "using up your No Stop time or remaining gas" beats me - looking at your buddy's BC maybe, or reading a book?

So to answer the journalist's question I always end my dive when my gas reaches its pre-determined limit or after an agreed bottom time. This applies to everyone I know and have ever dived with.

Chris
 
scubadobadoo:
I believe the Nitrox advantage to be miniscule...
Depends on how it's used. Decompression divers would argue this no end.

scubadobadoo:
I'll still use it when appropriate and will take any small advantage I can get, even if that advantage is only theoretical.

Theoritical? Right.:wink:
 

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