decompression without training

[dumpsterDiver]

NW GRatefulldiver: I really liked the article you wrote for basic recreational divers. However, there is ONE piece that I think should be tweeked and Howard made this point clearly in an ealier post. You advise to IMMEDIATELY begin an ascent if you notice you have accidentally entered into a required DECO status.

I would rather read that you recommend that the diver begin their ascent "as soon as it is safe to do so (and certainly within one or two minutes). If the diver needs to stay at depth to traverse 50 feet of a wreck in order to make the anchor line, then that is what should be done. Also, if buddy diving, the diver needs to try to ascend with their buddy, rather than "begin the ascent immediately". If the diver has air, entering into deco is only a "mild emergency".


I've noted that some new divers about panic when they see the flashing deco sign and tend to expedite their ascent more than might be advisable.

For the new diver, the flashing deco and the feeling that they must ascend IMMEDIATELY can produce unneeded stress and might endanger them.

 

[dumpsterDiver]

Too important to not have more of a safety margin than "a few inches" between a scheduled stop and where I might stray to. But I am an NDL diver, so I'll accept it if you tell me that people routinely hold their stops that well. Clearly too, I will remain an NDL diver, because I am okay with a safety stop that ranges anywhere between 14 and 16 feet, for example.

It is important to be able to control your bouyancy and position on a deco dive, but for relatively short deco like I do (30-35 minutes, usually much less), I don't hold my position that closely (within a foot) and I've not yet been bent from it. When I get to 20 feet, I usually deploy a smb and hang under it which helps me to hold position pretty well, but wave action can move me around some..


I also tend to stay 5 feet below my required ceiling (except when on oxygen), so a little floating upward shouldn't be too serious. However, deco diving is pretty serious and there are more than enough resources available to people to learn to do it with some degree of confidence.

Divers really need to have many dives under their belt before they think of planning on deco dives. As NWGrateful diver said in his article, if you enter into a little deco, a slow ascent and a deep stop should clear your deco well before you make it to 20 feet. Bouncing up and down 2 feet on a 50 ft stop is not a big deal compared to doing it at 10 feet.

 

[H2Andy]

i can hold my bouyancy within one foot up or down, no problem

i do drift up and down a little every once in a while, enough for the depth gauge to register a foot increment or decrease

most of the time, i can peg it at a particular depth, but as i said, i do go up and down every once in a while

as far as i can tell, this has never had a negative effect on me

 

[MXGratefulDiver]

NW GRatefulldiver: I really liked the article you wrote for basic recreational divers. However, there is ONE piece that I think should be tweeked and Howard made this point clearly in an ealier post. You advise to IMMEDIATELY begin an ascent if you notice you have accidentally entered into a required DECO status.

I would rather read that you recommend that the diver begin their ascent "as soon as it is safe to do so (and certainly within one or two minutes). If the diver needs to stay at depth to traverse 50 feet of a wreck in order to make the anchor line, then that is what should be done. Also, if buddy diving, the diver needs to try to ascend with their buddy, rather than "begin the ascent immediately". If the diver has air, entering into deco is only a "mild emergency".

I've noted that some new divers about panic when they see the flashing deco sign and tend to expedite their ascent more than might be advisable.

For the new diver, the flashing deco and the feeling that they must ascend IMMEDIATELY can produce unneeded stress and might endanger them.

That is a very good point ...

... Bob (Grateful Diver)

 

[seasick]

I would highly recommend Mark Powell's Deco for Divers as a single, extremely readable resource on decompression theory.

I will second the book by Mark Powell. Explains deco theory in plain simple english.

However, I would strongly suggest to get the proper training & experience before doing deco dives.

Regards,
SS

 

[AfterDark]

The majority of recreational SCUBA diving courses are kept within the No Decompression Limits of the table followed by that particular certification agency. This is one of the tenets of not having to submit to a government agency for regulation of recreational diving. At least here in the U.S.

When you leave the limits of the reccognized tables you are now in the realm of Technical Diving and you are no longer within the scope of training of the standard recreational SCUBA diving certification. There are a few organizations that do train decompression diving and other specialties like cave and werck penitration diving (i.e. GUE, TDI), but the amount of equipment needed and amount time time required far exceeds any standard certification.

No doubt this is all true and you are spot on. It doesn't change MO that it is a load of that which makes the grass grow green. I've done many deco dives and I couldn't tell you what any of these cert class consist of as I've only taken one. As someone stated there's nothing magical about deco. I might have know big brother nanny state was at the bottom of this mulit cert BS. As I've stated else where we covered all this in my original scuba course of 12 weeks. That taught me everything I needed to know, to learn and understand on my own, and with help from others that were doing it, what today is called the "technical" aspects of diving.
About the only things I haven't done in diving is cave and rebreather diving. Cave I have no interest in and rebreathers are way past my budget.

 

[Diver0001]

Im getting my first dive comp in the mail in a couple days and I want to know how often have you/did you go into decompression mode (either accidentally or purposefully) without deco training. How safe is this (im guessing not very)? Please elaborate.

I'm curious why you're asking this question. Can you elaborate?

R..

 

[11kiwidiver]

I wanted to know if it was a common practice... and the risks involved

 

[Bubbletrubble]

I wanted to know if it was a common practice... and the risks involved

@scubasteve0011: This is a reasonable answer.

I think the sentiment that many in this thread are articulating is that putting your computer into deco mode when you lack deco training is a bad habit. As a musician, you understand that if you practice bad habits, you can expect to see those bad habits come out on performance night. In music, that can result in just a poor performance. In scuba diving, bad habits can be lethal.
Be conservative. Be disciplined. Dive within your training. And, most importantly, have fun!

Enjoy your new computer.

 

[Diver0001]

I wanted to know if it was a common practice... and the risks involved

Well just speaking from personal observation I don't think there are a lot of divers who do decompression dives at all and of the portion who do them then only a small fraction of those do it unplanned and/or without the proper training.

So no, it's not a common practice. A small fraction of a small fraction of people do what you're asking about.

The big obvious risk that you run if you do this is that you'll get decompression sickness by either not having enough time to complete your decompression because you got forced out of the water for some reason like a gear problem or running out gas prematurely;

or that the quality of the decompression (ie, the curve of the ascent and the length of time spent at different depths along the way) wasn't that great.

I initially thought that you might just be curious to see your computer in deco mode. I would be too.... but if you're planning on dabbling in deco diving then you need to modify your gear to some extent (to add redundancy) and you really should get some training in "procedures" so you have an idea how to plan the dive for safety (especially the gas planning) and *why* things are done in certain ways.

R..