Deco with too less air, options from the book

[rstofer]

Even if you have taken leave of your senses you then send the yellow back up to get a drop tank. As taught everywhere.

I'm have a little trouble understanding the phrase "send the yellow back up to get a drop tank". Are you talking about an SMB with a slate requesting a tank?

Richard

 

[String]

I can calculate the air usuage on land, I doubt I can calculate it under water while making the deco.

Which is why you calculate it all on land then STICK to the depths and runtimes underwater.

 

[String]

I'm have a little trouble understanding the phrase "send the yellow back up to get a drop tank". Are you talking about an SMB with a slate requesting a tank?

Richard

Sorry. Typo. That should read "yellow bag". Meaning yellow DSMB which in large parts of the world is the "need gas" emergency signal. Slate is optional. I wouldnt waste extra time and gas writing on it unless it was some complicated problem.

 

[texdiveguy]

International Training :: Get Certified :: TDI Diver Level Courses

 

[Rhone Man]

As a general comment on SB, I always hate posters who think that: "Well you shouldn't have gotten yourself into that situation" is a constructive and helpful response to the question: what should you do if you ever find yourself in that situation? I think when we are in a jam we all realise what we should have done differently to avoid the situation - what we wish we had is some divine guidance on is the best way out of the mess. So kick the idea around on the message boards and see if you get some constructive thoughts on what you might do.

I am a non-Tec diver who has, in his sordid past, had to do unplanned deco from time to time. I suspect that I am not alone. ^*&#$ happens - usually because its our own fault, admittedly, but it still happens.

For what it is worth, if I found myself hanging on a deco line and running out of gas (and no buddy, or buddy was in a the same hole) my inclination would be try the old US Navy standard: if you can pull it off in less than 3 minutes: get on the boat, grab a fresh tank and get back down.

In terms of bubble formation theory, and should you skip deep or should you skip shallow - I doubt anybody has a definitive answer; it is still just too imprecise a science. But in practical terms: if you omit deep and maximise your shallow stop (i) your gas will last longer, and (ii) if you feel a hit coming on whilst down, you are closer to the surface to bail.

No idea if that is sensible or not, but I suspect that would be my thinking in the situation.

I sincerely hope I never have to make the decision(s) though.

 

[String]

As a general comment on SB, I always hate posters who think that: "Well you shouldn't have gotten yourself into that situation" is a constructive and helpful response

I think its very constructive. If it helps to stop people doing idiotic things then its useful.
A "bit" of deco by accident isnt going to hurt anyone if missed. You can skip 5-10 mins almost certainly without issue especially given how conservative tables and computers are now. If you're doing more than that it gets a lot more serious and unless you've planned it properly you have no business even considering it.

If someone is stupid enough to run up large amounts of deco AND not bother planning their gas AND not bother having a buddy then they really do deserve all they get and no amount of massaging their ego is going to help. This situation cant arise with someone doing ONE thing wrong or even TWO things wrong. They have to do at least 4 things wrong at the same time.

 

[tedj101]

That it probably hasn't been tested (at least in a scientific way) is hardly surprising. Who would you get to test it?

<TED>

I don't know what I would do in every scenario but my general reaction in most lost-gas cases would be to (a) try to calculate if I could finish my deco normally and do that if possible and failing that (b) ascend to my ceiling and try to make whatever gas I had left last as long as it could.

I don't think there is a good cook book answer to every lost gas incident beacause you probably never lose the same amount of gas each time and you'll never lose it all at once. The chances (especially diving in a team) of having a total loss of all deco gas is incredibly small.

Either way I don't know if my way is the right thing to do, I"m just telling you what my own personal reaction would be given zero time to prepare.

As for your book, you need to carefully consider who wrote it. Some deco theorists are *much* more interested in *appearing* to be experts in the real world applications of their theories than they are in the actual health and safety of divers. In fact, in some cases I think there is literally zero hard evidence that the things being perscribed actually work the way the theorist thinks they will, which leaves YOU in the roll of "Guinea pig" if you choose to blindly do what they say. I would advise skepticism because some deco theorists are trying really hard to get rich on their intellectual property and it gives me alarm bells (personal opinion).

Where does this leave you? In limbo, I'm afraid. Your scenario (skipping deep stops to extend shallow stops vs. doing deep stops and running out of gas sooner on shallow stops) is somthing that hasn't, as far as I know, been tested in proper laboratory conditions against *any* deco model.

R..

 

[DaleC]

Not all scenarios occur from diver error.
What if you are diving your plan, as planned, and your buddy begins experiencing a medical emergency. He/she is still conscious but fading and you have to make the choice between shaving some deco off or having the buddy become unresponsive/unconscious under water.

 

[Rhone Man]

Not all scenarios occur from diver error.
What if you are diving your plan, as planned, and your buddy begins experiencing a medical emergency. He/she is still conscious but fading and you have to make the choice between shaving some deco off or having the buddy become unresponsive/unconscious under water.

Sure, or the burst disk on your deco mix could blow at the end of your bottom time. Lots of possibilities.

 

[Kern]

What if you are diving your plan, as planned, and your buddy begins experiencing a medical emergency. He/she is still conscious but fading and you have to make the choice between shaving some deco off or having the buddy become unresponsive/unconscious under water.

Do the training & you learn that there are procedures for such eventualities.

Sure, or the burst disk on your deco mix could blow at the end of your bottom time. Lots of possibilities.

Proper planning that includes lost deco gasses & there is no problem.