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

[iamjblevine]

IMO something that should be addressed or stressed besides air planning is the accidental deco planning in the event of a computer failure. I don't tech dive, but run VPlanner for deep dives for 5 minutes over NDL, 10 minutes over NDL, and 10' too deep. I write out the matrix on my slate in case of computer failure. Yes I carry a backup computer, but it serves as a reality check should I misinterpret the information on the computer in the excitement.

 

[Ontwreckdiver]

---------- Post added January 6th, 2014 at 12:40 PM ----------


There is no decompression discussed or permitted in the Adv Nitrox course. That is covered in the Decompression Procedures course, which is full-blown, not bare minimum deco.[/QUOTE]



When I did the course during the classroom sessions we used the instructors deco planner to plan simulated deco dives and plan our own dives (above 130'). At depth we used our reels and practiced removing & replacing our stage bottles. On every dive we blew lift bags and reeled up to about 20 ft, switched from back gas to our stage bottle and did our "deco" stop and then our safety stop. Maybe my instructor went above and beyond in preparation for our deco procedures.

I should point out that did not do any actual decompression dives, they were all simulated.

 

[maniago]

The manual that came with my Suunto computer explained how to interpret the display should it ever indicate an obligatory deco stop, and what a "ceiling" is. It uses the terms "ceiling" and "floor" and appears to be written an in introductory manner for rec divers who are unfamiliar with these terms. Beyond that, I can't imagine any OW diver not having at least a rough grasp of how depth and time relate to ongassing and offgassing. With that basic concept in mind, the computer's introduction to ceilings and floors should make intuitive sense and provide everything one needs to know to handle the situation should it occur.

Dude, pdf me a copy of your Suunto pages. Better yet, make it available to everyone. My Oceanic manual is a mash of pics, flowcharts, 1.2.3's and something that passes for Chenglish. Its a great computer and I love it, but I've had to read and research to understand what its telling me elsewhere. Can you dig my frustration, Man?

 

[Lorenzoid]

Dude, pdf me a copy of your Suunto pages. Better yet, make it available to everyone. My Oceanic manual is a mash of pics, flowcharts, 1.2.3's and something that passes for Chenglish. Its a great computer and I love it, but I've had to read and research to understand what its telling me elsewhere. Can you dig my frustration, Man?

http://ns.suunto.com/Manuals/D6/Userguides/Suunto_D6_users_guide_EN.pdf

See Section 6.1.5. The word "CEILING" actually appears on the display when the computer goes into deco mode. People can knock Suunto computers if they wish, but I have to say that Suunto manuals are fairly well written, not Chinggrish or even Finnglish by any means.

 

[Dive-aholic]

But that pulls the student into true tech. I most specifically do NOT want some divers to be given the tools for technical diving. I feel that it would be wise to offer the safety layer (borrowed from tech diving) to certain classes of divers. The physically unfit, PFO's, chronically inattentive, maybe even the very young and aggressive diver.

Then those divers shouldn't be given the tools for technical diving. But they should also not be venturing into the world of technical diving using recreational tools. As for a safety layer, if you're physically unfit the answer is not to increase the difficulty of the dive just to have some additional option such as using 100% deco on a safety stop. The answer is to get physically fit. People with PFOs that are cleared to dive and just need some O2 can take TDI Advanced Nitrox as a standalone course. Max depth 130', no decompression allowed, max mix 100% O2. Chronically inattentive and very young or aggressive divers also need to fix the problem. Your simply providing bandaids for issues that need to be addressed head on. You're treating the symptoms rather than curing the disease. I withhold certifications from people like that because of those very things. I certainly would not want to allow a diver who is chronically inattentive to have 100% O2 because I'd fear the inattentiveness would result in the diver breathing that O2 too deep.

 

[Nwcid]

One of my computers did the "10 foot" thing and it was NOT telling you to go to 10 feet. What that unit, VEO 100, was telling you is that you were 10' or more below your first deco stop. So the short version is it was telling you to go up 10' NOT go up to 10'.

Someone had asked about book learning, Deco for Divers by Mark Powell

 

[Dive-aholic]

I'm interested in this same area of understanding as the OP. That said, reading the computer manual doesnt hack it for me - if my computer goes deco, it basically aborts the dive and tells me to go to 10' and wait there for some specific time, completely ignoring what depth I'm at. It doesn't help me understand what is going on, just "gets me outta here".

Before I go to a PADI40 or GUE Fundies course, I'd like some written education about what deco procedures entails and be walked through a simulation or something - I don't want to enroll and then discover its not for me.

Where does one go to read the book knowledge?

TDI Decompression Procedures Student Manual [decoproc] - $30.00 : Chipola Divers, Sidemount, Technical, & Cave Diving Instruction & Mentoring

 

[rivers]

If you want her to have a better understanding of deco and what that means, have her read "Deco for Divers" by Mark Powell.

 

[lowviz]

Then those divers shouldn't be given the tools for technical diving. But they should also not be venturing into the world of technical diving using recreational tools. ...//...

That IS the traditional view, and I expected a lot more push-back from "traditionalists" than I got. Someone described the NDL as being a sharp line drawn through a grey area. As one's true physical NDL is both variable and impossible to locate with certainty, one can find oneself on either side of that line if diving aggressively while technically obeying "the rules".

I see the value of educating recreational divers in light deco theory, but I also see the threat of removing the "fear factor" from the NDL. I still believe that setting conservatism high and entering light deco is better than an aggressive dive plan that takes one right up to the NDL.

 

[doctormike]

Someone described the NDL as being a sharp line drawn through a grey area. As one's true physical NDL is both variable and impossible to locate with certainty, one can find oneself on either side of that line if diving aggressively while technicallly obeying "the rules".

Here's an example from the relatively simple field quantum physics which will help explain the more complex field of deco theory.

You know how you are originally taught that the electron orbits around the nucleus of an atom like a tiny solar system? Then you realize that the electron is not so much a single point, but more of a probability field, and that what we think of as it's orbit is more of a shorthand graphic way of describing its probably location in space.

Same with NDL. All tables and computer can do is give you odds, probability of getting bent. As I mentioned, you can (and I have) get a DCS hit while staying far within the NDL. And some people do dives that should leave them dead or bent for life, and survive them just fine...

So dive with that in mind. 99% of your NDL is not much safer than 101% of it.