More than "Advanced", but not really "Technical"

[PfcAJ]

unwilling to make that investment to learn.

There ya go. I removed the unneeded words for you so we can get to the heart of the matter.

 

[boulderjohn]

Interesting arguments. Several have mentioned the use of high EAN concentrations. The course for this, TDI Advanced Nitrox specifically has no doubles requirement and it is actually fairly easy to find an instructor willing to teach this without full "tech gear." It seems to be the DP course that raises the "tech" radar and the apparently arbitrary rules such as doubles. I even spoke with one instructor more than willing to teach AN but would not include DP unless the diver had all his own gear including "tech regs."

For almost all divers, there is no point in taking the Advanced Nitrox class without taking the Decompression Procedures course. Why would you use such high percentages of oxygen except for decompression?

tursiops, you just made my argument. The doubles is an arbitrary, instructor based requirement, that can be a hardship for some divers that just want the knowledge with the potential to go more gear intensive in the future if they find this is the right option for them.

I may not be understanding your argument properly. Let me say it in different terms to see if I have it right.

You want to be able to gain all the knowledge about how to do a dangerous and potentially fatal practice without being required to have the gear and training required to do it safely.

Is that accurate?

 

[maniago]

I may not be understanding your argument properly. Let me say it in different terms to see if I have it right.

You want to be able to gain all the knowledge about how to do a dangerous and potentially fatal practice without being required to have the gear and training required to do it safely.
Is that accurate?

ok, so not trying to speak for Lisa, but in general, no, I don't think that's where divers like us who are probing this topic are.

In the beginning, it was a matter of being on a single tank dive to lets say 120', you over stayed your welcome and incurred a deco obligation for whatever reason, and now want to understand how to get out of it AND not blindly rely on your computer. That sort of transitioned to, I'm still single tanking at 120' and want to be able to plan a deco dive within the limits of my single tank. Why is that heresy? I don't want to be told is "the rules say you cant do that with that equipment". What I want to understand wrt planning is what are the limits of my equipment wrt deco and why. Why? Why? Why?

 

[uncfnp]

You want to be able to gain all the knowledge about how to do a dangerous and potentially fatal practice without being required to have the gear and training required to do it safely.

Is that accurate?

*sign* No boulderjohn. Its just the opposite. I want the instruction and the guidance. I want to do the dives, as specified by TDI. Otherwise I can just take the AN course (readily available) then go out and do any dive I like, on my own, no decompression course needed. Just fly my computer...

 

[tursiops]

Interesting arguments. Several have mentioned the use of high EAN concentrations. The course for this, TDI Advanced Nitrox specifically has no doubles requirement and it is actually fairly easy to find an instructor willing to teach this without full "tech gear." It seems to be the DP course that raises the "tech" radar and the apparently arbitrary rules such as doubles. I even spoke with one instructor more than willing to teach AN but would not include DP unless the diver had all his own gear including "tech regs."

AN has no deco in it. No big deal on virtual overheads, unanticipated gas management issues, etc.
I don't know why you keep mentioning "arbitrary rules" about doubles in DP. There is no requirement for doubles, but there is for redundancy and good gas management....which if you are going to 150 ft with real deco needs you are not going to do with an AL80 tank on your back and a pony on your side. So some instructors choose not to instruct you if you are not going to actually do what the course is designed for. Isn't that better than giving you a card that lets you do much more than you were actually trained for? (I hope you say Yes!)

---------- Post added January 14th, 2014 at 04:31 PM ----------

tursiops, you just made my argument. The doubles is an arbitrary, instructor based requirement, that can be a hardship for some divers that just want the knowledge with the potential to go more gear intensive in the future if they find this is the right option for them.

I certainly did not intend to make your argument for you. I think your argument sucks!

---------- Post added January 14th, 2014 at 04:36 PM ----------

one size fits all "full tech" route. And I hope that perhaps I gave gotten at least a few instructor to think about the hardcore tech approach that some have shown and instead consider each student's individual needs within the confines of a safe and through dive course.

Why do you keep talking about one size fits all and "full tech"? There is at least once course that seems to be aimed at what you are asking for: Tec40.

Finally, it is not an instructor issue......I can't teach you a course unless there is a course to teach that is offered by an agency. And given the fact that people are going out and killing themselves by lack of training, I'm not sure I want the agency to provide me with something that might encourage you to do that.

---------- Post added January 14th, 2014 at 04:40 PM ----------

*sign* No boulderjohn. Its just the opposite. I want the instruction and the guidance. I want to do the dives, as specified by TDI. Otherwise I can just take the AN course (readily available) then go out and do any dive I like, on my own, no decompression course needed. Just fly my computer...

I seriously do not understand your point. Just go do it. let Darwin be your instructor.

Are you looking for permission? You are clearly not caring about training.

 

[uncfnp]

..//...
I seriously do not understand ...//...

Again, we agree!

 

[boulderjohn]

ok, so not trying to speak for Lisa, but in general, no, I don't think that's where divers like us who are probing this topic are.

In the beginning, it was a matter of being on a single tank dive to lets say 120', you over stayed your welcome and incurred a deco obligation for whatever reason, and now want to understand how to get out of it AND not blindly rely on your computer. That sort of transitioned to, I'm still single tanking at 120' and want to be able to plan a deco dive within the limits of my single tank. Why is that heresy? I don't want to be told " the rules say you cant do that with that equipment" What I want to understand wrt planning is what are the limits of my equipment wrt deco and why.

As someone who is certified to teach decompression skills, if in my own diving I accidentally strayed into deco, I would follow my computer to the surface. Seriously.

Planning deco as is done in these classes is done with high O2 levels with mutliple gases is an entirely different thing. If I am planning deco, it is not going to be with a single tank, and it not going to be for staying into deco for a few minutes.

What's the difference?

With a single tank short stray into deco, my computer is going to tell me to do an extended safety stop. That's all. If two different computers give different values of that extended stop, as they probably will, it's not a big deal to me. The odds that I am going to get into DCS because of the difference of a minute or two of a stop is pretty remote. In fact, if I were to miss the deco stop entirely, I would probably still be all right. Why would I miss the stop? Well, maybe I ran out of air when I strayed into deco. Maybe I had a valve failure. Lots of possibilities. That's why redundant air is not as important in NDL diving. That is why I don't consider the variations in algorithms among the different computer models to be a big deal. Deco theory just isn't that precise.

With planned decompression, it is another issue. Although the precise lengths and depths of the stops can again vary between algorithms, the minimum lengths are such that you can be sure you really do need to do those stops. If you blow off the deco, you really are at risk for DCS, and I am not talking about a simple case of skin bends. Therefore, you need to be sure you can solve all your problems at depth. You can't be running out of gas, so you need plenty of reserve. If your valve fails, you need to be able to shut it off and go to a different one.

And you need to carry additional gas in a different tank, so you need to be able to switch safely. That's a skill that must be taught. But you can switch to a pony safely already, right? Sure you can. But your pony has the same gas as your back gas, and you don't have a real deco obligation, so if you accidentally ascend 20-30 feet while making that switch, it's no big deal. If you accidentally descend 20-30 feet, it's no big deal. In contrast, if you ascend or descend those distances while doing a decompression stop, life can become very unpleasant. Let's say you are switching to 50% O2 at 70 feet and accidentally descend 30 feet while you are doing that. You will now be breathing a PPO2 of 2.0 and risking a seizure. If you ascend 30 feet during the switch, you have just blown off three deco stops. If you think that skill is so easy that it won't happen to you, then you have never seen students practicing in a decompression procedures class.

Next, what do you do when your decompression bottle goes bad and you don't have it available to you?

There is a lot to learn before you get into planned, multigas deco.

 

[uncfnp]

Guys (and interesting that it is mostly guys), you do realize that this is all theoretical? But in fact, to do pretty much what I have suggested, all I need to do is take TDI AN and PADI Tec 40.

 

[Basking Ridge Diver]

That fits the other extreme end of the course description. I'm interested in what the minimum requirements are for someone who just wants to understand what happens when one crosses the line and has the gas to return, but not the knowledge...

I am curious I am looking at NAUI dive tables and maybe I dont understand - but at 120 ft at 12 mins you are clear. At 120 ft at 15 mins or less you owe 5 mins of deco stop at 15 feet but I like 20 feet. At 120ft at 25 mins or less you owe 6 mins deco stop at 15 feet. At 120 ft at 30 mins or less you owe 14 mins deco stop at 15 feet.
How much further did you want to go and call it lite deco? Are you asking beyond 30 mins? If so I agree with the others take the class and be the wiser.

 

[Lorenzoid]

Guys (and interesting that it is mostly guys), you do realize that this is all theoretical? But in fact, to do pretty much what I have suggested, all I need to do is take TDI AN and PADI Tec 40.

I had been thinking of asking but was hesitant to chime in. Do you want to take a class purely out of academic interest and not because you want to do "light deco" dives? If it's purely out of academic interest, then there are no skills to practice, and you could learn all about it from sources other than an instructor, couldn't you?