... But what's the motivation in shouting about it, or pushing for it to be a recognised diving discipline?
For the life of me, I can't figure that one out.
You can't do the decompression stop without the gas,
And you won't have the gas unless you planned for it,
And you can't plan for it without the knowledge,
And you won't have the knowledge without the training,
And you won't get the training in a recreational course.
Cute, succinct, deceptively straightforward, with just enough truth to hide the realities: plenty of folks dive huge or doubles because they can't do math; you don't need to take a class to gain knowledge about something; there are recreational courses that cover decompression, at least as a contingency and most all courses do a three at ten, but call it a "safety stop," it is really a just-in-case decompression stop.
To me - the issue revolves around the necessity to maintain the deco stop. It's a virtual ceiling, but nonetheless it is very real.
It does not surprise me that you see divers who can't hold a stop, but should they all not have demonstrated the ability to adequately hold a three minute stop at a specified depth between twenty and ten feet? Or are you trying to turn that into another PADI separately priced product like PPB?
Technical diving isn't just about the use of exotic gasses - it's about having a very high standard of core skills, extensive planning/preparation and covering all reasonable contingencies so that the deco obligation can be achieved. Nothing in the recreational diving syllabus comes close to providing that level of training, that focus or that mindset.
Perhaps nothing in YOUR comes close to providing that level of training, that focus or that mindset, but you have no business speaking for everyone else.
Any argument that divers can take a 'recreational' approach to decompression diving has to be based on a limited scope of decompression. It has to be 'light' decompression. What I see in those arguments is a mindset to deco that links 'light' with 'safe if broken'. "It's only 6 minutes, so if I screw up, then I'll be ok". In essence, it is reducing 'light deco' to the status of a glorified safety stop. It's a dangerous and irresponsible mindset to encourage/allow.
"Safe when broken" is a "safety stop" not a decompression stop. I don't know the exact difference between "light" deco and deco, but I do know that if there's just a ten foot stop I'd tend to call it light and if there is a required 30 foot stop I would not. Between those two there are lots or rather meaningless lines that everyone could scribble.
How many 6 minute light deco/glorified safety stops does the diver have to complete, before they feel confident and justified to extend to 10 minute stops? to 15 minutes? to 20 minutes?
It's less a question of how many and more a question of" "how well did they do the last one?" A diver who hits the stop with perfect buoyancy, never has to touch the line and does not vary depth more than a foot either way is ready for longer stops ... right? What does it matter how many times they've done it before?
How many times do they accidentally or deliberately break their virtual overhead, before they start to believe that "deco is all hype" and begin rationalising that the implications for skipped 'light' deco obligation are inconsequential? How long will it be before they start scoffing at "You're gonna die" comments when they gain the confidence to start admitting that they've blown their 'light' deco through lack of preparation, planning and/or dive ability.
Therein is encapsulated your skill as a teacher. If you have a problem with that you need to closely examine what you do and how you do it.
There really is no need to justify decompression without training. Training is now commonly available and easily accessible to the dive community. It's no longer a mysterious 'dark-side'.
It never was, all the information needed, and more, is right there, in the 1955 USN Manual, in the Science of Skin and Scuba of the same era, hell I think it was even in Bill Barada's, "Let's Go Diving." Hardly the "dark side."
This weekend I am teaching a PADI Tec40 course. My student has 50 dives experience, certified as an AOW & nitrox diver. The cost of his course is the same as I charge for an Open Water course. It'll take 4 days. The first day is 'recreational' deep open-water dives - 'check-outs' where I can assess and remediate his core skills. Then we have 3 days of 'tech'. The theory work is intense - detailed dive planning techniques, equipment configurations and 'technical mindset'. We also have 4 training dives. The first 3 dives are shallow-water and skills intensive. He'll learn to safely operate doubles and a single stage of nitrox (-/=50%). He will learn how to gas switch and hold a deco stop with precision. The course will finish with a single, planned decompression dive to a maximum depth of 40m/130ft with no more than 10 minutes of deco.
On qualification, he'll be certified to conduct decompression dives, to a maximum of 10 minutes deco, down to 40m/130ft, using nitrox up to 50%.
Isn't that the sort of 'light' deco we are talking about?
Does that course sound unreasonable in terms of scope, time, cost or commitment?
Does the course sound excessive for the benefits gained?
Is there any mystique or 'black magic' involved?
It sounds like a lot of makeup work that the student should have mastered previously, but didn't, so you had to provide it. Good thing you could and were willing to, but you really should be complaining about this student's previous teacher(s) rather than bragging on what a hard program you present.
My problem with the tech 40 as you describe is that it is light deco with training wheels. Max ten minutes deco? Most tech instructors I run into have very high standards for accepting anyone into a adv ntx/deco proc class. Either you are ready for 30 at 30 with 30 accumulated or you are not.
The major problem that most students I have trained have with longish stops is dealing with boredom not with skill performance.
I think that easing into the pool with light deco, no matter what we are calling it is a crutch. I would draw the line at an intro to tech class and then either go straight to you accept the risks involved with 30/30/30 or not. While education at an early stage is good, I do not agree with teaching so light a deco. The argument could be made that cause there is nothing to 30/130/10 then deco to deeper depths for longer is just as easy.
First you simulate, then you practice in simulation then you do it for real. Frankly I see no need to actually make a deep diver or expose anyone to the potential dangers of decompression in a decompression course, conducting a deep dive and decompressing on the way out are two different things and can be handle in an integrate or a separate fashion.
Again... I'll point out that there is a fundamental difference between 'being able to do a deco stop/dive' and being able to 'safely carry out decompression dives'.
Once again I must point out that safety means "without risk." There is no decompression diving that is without increased risk so the very idea of being able to 'safely carry out decompression dives' is claptrap. What one must do is learn to minimize risk whilst carrying out a decompression schedule. That is a very different mind set.
One situation supposes the ability to; carry enough gas, control your buoyancy and follow what your computer tells you to do.
The other situation supposes the ability to; do the above, but deal with any contingencies, providing a virtually guaranteed certainty of survival on every occasion, on a repeated basis, indefinitely.
Any properly trained open water diver should have the ability to; carry enough gas, control your buoyancy and follow what your computer tells you to do. Your other "situation" is quite impossible since there are no guarantees, not on any dive, especially not on one requiring decompression, which is a stochastic process, and thus never guaranteed.
Training isn't needed to do decompression dives? Ok.. but training is needed to do decompression dives safely, without reasonable risk of accident.
Training is not needed to do decompression dives, I did hundreds before I was mentored by someone who had done far fewer, but who had some good tricks. I guess it would be safe to say that I still have yet to be so "trained."
I have a library of diving instruction books and several issues of Navy diving manuals from 1955 to the present. Those and a YMCA scuba course in 1970 are all the whole of my instruction. I was doing what are now called tech dives long before the term came into use.
Say it isn't so Captain, please, say it isn't so!