Shallow Decompression Dives

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ScubaSteve

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This post has been triggered by another where somebody was given training on shallow decompression dives as part of an AOW course. I am sure there are likely many divers out there that absolutely love being underwater but really are not quite drawn to the "Technical" side (i.e. anything deeper than recreational limits). I am sure many divers are more than happy to dive reefs in 110', 80', 60' or any depth inside of Recreational depths (less than 130 ffw or fsw) but would love to be able to extend their bottom time by safely planning a decompression dive. I do not know what the CMAS course is (this was what I mentioned at the beginning) but, to all the knowledgeable types out there:

What does a recreational diver have available to them (course wise) to allow them to be trained to safely plan and execute shallow decompression dives?
 
Last April I completed the TDI Advanced Nitrox Class and this April I will be completing the TDI Decompression Procedures Course. Normally these two courses are taken together but, since my original Nitrox training was so bad, I took the Advanced Nitrox course as a stand alone class. TDI Advanced Nitrox/Decompression Procedures certifies you to plan and execute air/nitrox decompression dives using one decompression gas down to 150 feet.
 
This is a big watershed between Americans and Europeans - American dive agencies (at rec level) always teach deco is for emergencies only, even for highly experienced recreational divers. From a relatively early stage on the "certification ladder" BSAC and CMAS teach that properly planned deco is a perfectly acceptable way to extend bottom times.

I remember wondering when they brought in mandatory 15' safety stops into North American diver training whether some kind of transition would take place, but they seem as implaccably opposed to planned deco as ever.

But as they often say - there are no scuba police. I used to engage in planned deco diving before I got formal training in it. My mistake (which I know now, after I have received proper training) was thinking it was all about planning the deco. Now I realise that far more critical is planning the gas requirements.

If you wanted to engage in planned deco, I would suggest taking one of the basic tec diving courses. TDI usually teach Advanced Nitrox / Deco procedures as a good combo. It is not rocket science, but you learn valuable skills even if you don't plan to do much decompression diving.
 
What does a recreational diver have available to them (course wise) to allow them to be trained to safely plan and execute shallow decompression dives?

There are several courses available.

IANTD's advanced nitrox is a good entry level course for "shallow" decompression.

I think TDI has one, probably with similar content, called "deco procedures" or something like that.

As far as I know, these are among the most common entry-level deco courses.

I think PADI/DSAT has something similar but I don't have any experience diving with anyone who has taken those courses and I don't know about the content. All of my tekkie friends are IANTD trained. I read that the materials for the DSAT course are pretty good, for what that's worth.

Some CMAS variants teach deco procedures as a matter of course as far as I know (BSAC being one). However, CMAS has taken a very differnt approach to organising itself than PADI. If diving instruction was like an ice-cream stand, then the PADI stand would have 1 flavour and the CMAS stand would look like a rainbow exploded in it. To me it makes CMAS come across as highly chaotic but the high level of tailoring probably has some strong points too.... Problem with CMAS is you can't point at any particular example and say "that's how they teach it", so you can't really get a grip on what to expect.... Maybe if you're a little more versed in how it works than I am then it doesn't seem that way, so take that comment with a dose of skepticism.

The UTD course suggested (spinoff from the GUE mother-ship) will certainly teach you about decompression diving but be warned that the UTD and GUE teach a method that is unique to those two agencies and not well understood outside of a relatively small group of divers (read: you'll probably need to find GUE/UTD buddies, which implies "going DIR" if you want to use what you learned optimally).

I'm sure there are others I didn't mention or don't know about.

R..
 
IANTD's advanced nitrox is a good entry level course for "shallow" decompression.

Since it's very often combined with Deco Procedures, I'd forgotten that AEANx was limited to 130 feet.

I'm not sure how it's necessarily going to work to accomplish the dives suggested by the OP though since alone it appears (from the website) to be no-switch diving when taught alone ("during dives hat [sic] do not require staged decompression").

The UTD course suggested (spinoff from the GUE mother-ship) will certainly teach you about decompression diving but be warned that the UTD and GUE teach a method that is unique to those two agencies and not well understood outside of a relatively small group of divers (read: you'll probably need to find GUE/UTD buddies, which implies "going DIR" if you want to use what you learned optimally).

I imagine that any single course will involve some procedures and methodologies that are different than those found in other courses. That's the nature of non-standardized (on both macro aka cross-agency and micro aka instructor-to-instructor levels) training, and don't believe it's unique to "DIR".
 
RhoneMan -- Thanks for the the info on the difference between the US and the rest of the world regarding "recreational deco." This is an issue I've been discussing/questioning for quite some time -- or at least since I was introduced to "minimum deco" and "gas management" as part of my diving evolution/education.

What DO you need to know and be able to do to "do decompression?" Here's my take: (and it is worth EXACTLY what you are paying for it)

a. It ain't rocket science.

b. Whether it is a computer on your wrist or a computer on your table back home, it is still a computer program that is guestimating how much decompression you need and where.

c. You do need to know a few things and have a few skills before planning "recreational deco" dives:

1. Gas planning -- as RM wrote, the real secret to Decompression diving appears to be being able to accurately plan for the gas you and your buddy need to do the dive. As long as you treat the deco obligation as a real ceiling and include it into your Gas Plan obligations (and that includes Minimum Gas Reserves), no problem -- enough gas, you are golden.

2. Deco plan itself -- whether following a computer program, using Ratio Deco or whatever, its all "voodoo" to some extent and each dive is a human experiment.

3. The one physical skill needed is to be able to hold a stop for whatever length of time you'll need -- AND TO BE ABLE TO DEAL WITH EMERGENCIES WHILE DOING SO. The difference between deco diving and recreational diving is that you need to fix a problem where you are. Can you hold a stop and donate gas to your buddy? Can you hold a stop and shoot an SMB? Can you hold a stop and manipulate your valves? Can you hold a stop and do "X"? These are skills that are NOT generally taught in OW or AOW -- but these are skills you need to do "recreational deco."

It's a fun "slippery slope" from "recreational diving" to "technical diving" and I must admit I'm having a good time sliding.

- - - - - - - - - - - - - -
NOTE -- This may be one of those examples where taking "a class" might not be the best way to learn what is needed. Instead of a class, find an instructor who is willing to go diving with you and "give you some pointers" to get to where you want to go (and here I'm assuming starting with back-gas deco). I had the privilege of "getting some lessons" from a wonderful teacher and working on "C)3)" above and I learned much more than I would have had I taken "a class" I believe. I think it is unfortunate that more people don't hire an instructor to work on a particular skill/issue as opposed to taking a class.
 
Since it's very often combined with Deco Procedures, I'd forgotten that AEANx was limited to 130 feet.

I'm not sure how it's necessarily going to work to accomplish the dives suggested by the OP though since alone it appears (from the website) to be no-switch diving when taught alone ("during dives hat [sic] do not require staged decompression").

Yeah I'm not sure where one thing ends and the next thing begins in the IANTD system. I took a bunch of courses bundled into one thing because a friend of mine was giving it.

I imagine that any single course will involve some procedures and methodologies that are different than those found in other courses. That's the nature of non-standardized (on both macro aka cross-agency and micro aka instructor-to-instructor levels) training, and don't believe it's unique to "DIR".

Yeah, that's true but what I was trying to get across s that not many divers are trained in ratio deco and most of your run-of-the-mill tek buddies are probably going to want to cut tables and plan the dives along more traditional lines. I'm not sure that paradigm gap would be easy to bridge. It's not a judgement call either way.

R..
 
What does a recreational diver have available to them (course wise) to allow them to be trained to safely plan and execute shallow decompression dives?

Most deco classes do short bouncy 20ish min dives to 130-150ft (some ~1 ata deeper to 170-180ish). Its a bit more efficient than trying to do a long dive (that often ends up multileveling) and then doing 15-20mins deco on top of that. Long shallow is not any "easier".

So to answer your question, there really isn't an agency or course teaching ~70ft dives with deco. Even the UTD course ("tech1") mentioned empahsizes the 100-130ft range on 25/25 trimix.
 
The above posts give excellent information. Here is my take:
-No one KNOWS what causes DCS. There are many theories and even some good science on the subject. But, as applied to the human body no one knows exactly what causes DCS. So, as applied to each individual diver every dive is an experimental dive.
-Every dive is a decompression dive. But, over time and with experience certain profiles have been accepted as being relatively free from DCS whether a decompression stop is made, or not. Hence, the "Safety Stop" is recommended, but not mandatory and other stops are considered mandatory.
-There are several algorithms that are available for selection by the diver. Once chosen for maximum relative safety it is important that the diver follow the dive profile that results. A key argument here is how accurately a diver needs to follow the profile. Is varying a stop depth by 1' acceptable? How about 5'? More? Is varying a stop time by 1" ok? How about 5"? These are ongoing discussions that may never be resolved in our lifetimes.
-The thousands of dives conducted each year with only a few cases of DCS supports the idea that DCS is a rare event. On the other hand injuries from barotrauma (DCI) appear to be fairly common. Therefore, based on risk management principles, a prudent diver should pay much more attention to DCI prevention.
-Like other aspects of life diving is very much a case of risk management in the face of uncertainty caused by lack of firm knowledge. One cannot avoid risk.
 

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