From: rbeck@mordor.dseg.ti.com (Ron Beck)
Subject: Re: missing deco stop .. re-entering -- Dive Computer query
Reply-To: rbeck@mordor.dseg.ti.com
Organization: is an esoteric concept.
Date: Fri, 18 Dec 1992 18:09:28 GMT

In article <dan.74.0@basil.eng.monash.edu.au>, dan@basil.eng.monash.edu.au (Dan Grimm) writes:
|> In article <1992Dec7.174921.26492@mailer.cc.fsu.edu> mayne@phi.cs.fsu.edu (William Mayne) writes:
|> [Chomp lots]
|> >>So what if you are on a dive and have omitted a stop?  
|> What should you do with a dive computer?
|> If I remember my Suunto SME-ML manual, it will go into error mode (show 
|> ERROR) if you shoot to the surface without doing required decompression.
|> 
|> My basic thought is that (and here I admit that I have very little deco. 
|> diving experience) grabbing a tank and jumping back in to a reasonable depth 
|> as soon as possible (from memory in 'Deeper into diving' most of the tables 
|> that allowed for in water deco in emergencies gave you up to 5 minutes to 
|> get back to deeper than your planned stop) would be the way to go.
|> Naturally this assumes that your emergency got you out near your boat :-)
|> 
|> I assume that popping out and back in should have very little physical 
|> effect difference compared to going up to 10 feet say and grabbing another 
|> tank for you proper deco.
|> 
If I remember right (and it's been a few years) the problem with "popping out
and back in" is the amount of pressure to return a bubble to solution.  Think
of a bottle of Coke.  When you pop the top off, all those bubbles start
forming.  Place the top back on and the bubbles slowly stop as the pressure
inside the bottle builds back up.  Nitrogen in the bloodstream works the same
way.  Again, if I remember right, it takes a significant amount of pressure
to put bubbles back into solution (5 ATM or 132 ft sticks in my mind).

Best bet... dive conservatively... watch your tables/computer... ALWAYS make
a 5at10 stop... and, if all else fails, get to a chamber for proper treatment.

Ron

|> The way I use the sme-ml is that I check it quite a bit, and know 
|> whether I am in deco time or not. It does show a ceiling for deco, and the 
|> aim on emergency recompression would be to get down to below the last 
|> ceiling seen.
|> In ERROR mode the sme-ml acts as a timer and depth guage only. ( I think 
|> that is what the manual says, although I have seen it come out of error mode 
|> back into normal dive computer mode).
|> Has anyone tried doing nasties to their dive computer: I'm thinking along 
|> the lines of take it for a good dive and then have someone haul it to the 
|> surface 'fast' so that it believes you have just missed required deco, and 
|> then have someone observe it as it is brought underwater again. I am very 
|> sure that this sort of procedure in some sort of chamber must be done by the 
|> manufacturers, but the few manuals that I have seen basically say don't 
|> miss any required deco. Which does not tell you what to do in an emergency.
|> 
|> 
|> >Clearly avoiding the problem is the goal. No one is arguing with that.
|> Agreement in full.
|> Dan Grimm
|> Dept. Elec & Comp. Sys. Engineering, Monash Uni. Australia.
|> ph.(+61 3) 565 3479, Fax 565 3454,     dan@basil.eng.monash.edu.au
|> 

-- 
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Ronald J. Beck           | IP rbeck@mordor.dseg.ti.com |Do now what others
Member, Group Tech Staff | MaBell (214) 952-4566       |won't so you can do
Texas Instruments        |                             |later what others
McKinney, Texas          |                             |can't
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