MHK, could you explain this statement/question? BRW says it's a concern when switching from a heavy to a light gas.
PADI TecRec
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MHK, could you explain this statement/question? BRW says it's a concern when switching from a heavy to a light gas.
The Pirate
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Man, I hope not. If anyone has, I hope they've updated their life insurance and purchased a plot in the local bone farm. That course is the reason I cancelled my membership in PADI. Everything about that course is wrong and outright dangerous. The people who created that course don't have a clue.
Everything?
What kind of membership did you cancel?
The Pirate
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Yes everything. Master Instructor, IDC staff instructor. I don't want anything to do with PADI at all. The Tec Rec course put it over the top for me. Its the most insane bunch of crap I've ever seen. As far as I'm concerned, its worse than IANTD or TDI.
Is TecRec all deep air or is there a mixed gas component?
Did you give up teaching or switch to a different agency? Which one?
Speaking for myself, I am very frustrated with all the agencies that I teach through (PADI and IANTD) I just don't have a solution which is why I'm asking. Maybe I'll start my own. LOL
MHK
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I'm not sure what you mean by BRW.. Generally speaking the concept of isobaric counter diffusion as discussed by Karl Shreeves of PADI is that when you switch gases, through, isobaric counter diffusion, bubbles appear even though you may not be changing depths. That's a very brief overview of Karl's position, see April 2001 Skin Diver article from Karl Shreeves entitled Trouble with Trimix, amongst many other articles he's written on the subject. So in short PADI believes that when you switch from a helium based mix to an elevated oxygen level mix through isobaric counter diffusion you increase bubble formation.. Atleast that is what they believed two years ago before they had a trimix class, I don't know what they will think when they release the Trimix class.
But if you read the Cowley, Allegra & Lambertsen study of 1979 and the Kang 1992 and review the Dueker 1979 study you'll see that the isobaric counter diffusion issue is a red-herring.
Specifically the study provided in both vivo and vitro that the Pmax was 48 +/- 10. This represents the standard deviation an the mean time to reach Pmax in minutes. However what is VERY VERY important to note, that in this study the used Nitrus Oxide. Nitros Oxide is approximately 20 times more soluble than nitrogen and substantially more soluble than Helium.. In other words isobaric counter diffusion would onset 20 times faster, assuming it's anyting to worry about. In the study the difference in the solubility coeffecients [ in other words when ISO "kicks in"] wasn't reached for 1500 minutes..
So in short, if you spent 1500 minutes on Nitus Oxide and then switched to a different mix this mythical "bubble concern" kicks in.. Now no recreational diver doing a 165' air dive is going to spend 1500 minutes on a gas 20 times more soluble then N2, which then begs the question, how the hell cares about isobaric counter diffusion???
My original set of questions that I posted has been ignored by PADI for years. I'm seriously not trying to bash PADI here, but as an instructor when I look at a program one of the first questions I ask about the content is " does it teach you what it purports to teach" In the case of the deep air program, there is fundamental physiological questions that need to be asked. If you are going to *certify* a diver as a deep air diver then it seems to me that the program needs to reconcile several long standing PADI positions that they have pioneered for years. Several years ago Drew Richardson, VP of PADI Training wrote an editorial in PADI's own Journal entitled the Danger's of Deep Air Diving and then went into great detail about why deep air diving was dangerous, and encouraged every PADI member to be vocal and speak out against any agency that was promoting deep air because in his view, there simply was no way to do it safely. Fast forward a few years, PADI now offer's the class and not a word is mentioned in terms of what has changed.. So in my mind before the program has a shred of credibility some simple and basic questions should be answered by the agency, and to date they refuse to address the issue.
Two years ago PADI was saying how dangerous Trimix was. At the time I predicated that they would sooner or later reverse courses and then, once again, divorce themselves from their previous positions. They have now announced they will be offering Trimix, but once again refuses to reconcile their positions.. To me the idea behind a program isn't pretty books and slick looking video's.. It's does the course teach you what you need to know, and I've asked some basic questions about deep air diving, and no one can answer them, so my answer is that the class probably doesn't teach you what you need to know..
Just my thoughts..
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That's Bruce Weinke's scubaboard name.
WW
SimonN
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MHK,
So, deep air aside (not worth having a discussion with you on this as we will disagree on what deep is), what you are saying is that PADI waited for others to test it for them? Now it has been proven safe they introduce their own courses.
Seems like a good idea to me.
As far as ICGD goes, this new study seems to show that something similar (at least from the perspective of my limited understanding)
http://www.diveoz.com.au/discussion_forums/topic.asp?TOPIC_ID=3066#35601
Cheers,
Si.
So, deep air aside (not worth having a discussion with you on this as we will disagree on what deep is), what you are saying is that PADI waited for others to test it for them? Now it has been proven safe they introduce their own courses.
Seems like a good idea to me.
As far as ICGD goes, this new study seems to show that something similar (at least from the perspective of my limited understanding)
http://www.diveoz.com.au/discussion_forums/topic.asp?TOPIC_ID=3066#35601
Cheers,
Si.
MHK
Guest
That isn't what I'm saying at all. What I'm trying to point out is that for decades PADI spoke out against the dangers associated with deep air diving, sych to the point that there very own VP of training wrote an article encouraging people to vocal in their opposition to ANY agency that promotes or advocates deep air training. Subsequent to that article no new information has been learned with respect to making deep air safer but yet they reversed a very core position and did so without explanation. Moreover, the most basic and fundamental issues respecting the class are still unanswered, so how can they have any credibility as to the "safety" of the class..
I still don't know how you can teach someone to overcome narcosis.. I still don't know how miraculously the density of the gas isn't an issue.. I still don't know how you avoid a C02 buildup.. And so on.. The class doesn't teach these very important basic concepts.. It seems to me that if an agency wants to retain any credibility then it is incumbent to explain how they can do a complete reversal of a core belief...
Just my approach to the issue..
Later
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