More Deco Reading?

[gsk3]

Hey Henrik,

It might help if you clarified what you want out of the other book. I found Deco for Divers to be a pretty complete book. What I wanted more of was actual equations, which he wisely avoided to keep the text approachable. Equations with explanations of equations would be perfect. I think Weinke has a book that's supposed to be useful. Also, Buhlmann's book, although out-of-print, would probably be extremely helpful.

Links you may find interesting:
VPM For Dummies - Rebreather World
/deepocean
DIY DECOMPRESSION

 

[Mod63]

Also, Buhlmann's book, although out-of-print, would probably be extremely helpful.

Bühlmanns book "Tauchmedizin", is currently available again - for the ones fluent in German . Be aware that it is now somewhat out-of-date, as there have been no major additions since Bühlmann passed away.

 

[Rhone Man]

I have always thought that there would be a good market for a really well written "technical diving encyclopedia". The GUE manuals are pretty comprehensive and user friendly; it wouldn't take much to spin them out into something pretty good for mainstream use.

 

[Mr Carcharodon]

Not sure if the site is still up but try: ftp://decompression.org Erik Baker's papers on dissolved gas models and gradient factor are very good. Baker's papers on decompession are the best around in terms of computational details. Also there is source code for VPM-B if you do not mind working in fortran.

On ratio deco worth reading is: Team foxturd: Tech1 Ratio Deco - Explained

 

[limeyx]

I have always thought that there would be a good market for a really well written "technical diving encyclopedia". The GUE manuals are pretty comprehensive and user friendly; it wouldn't take much to spin them out into something pretty good for mainstream use.

Except that a large number of tech divers don't agree with much/any/all of what GUE may or may not have to say

 

[HenrikBP]

Hey Henrik,

It might help if you clarified what you want out of the other book. I found Deco for Divers to be a pretty complete book

thanks Ari. you're right. I liked Deco for Divers as well, and a reread will help, but I guess Im looking for different ways of explaining the various theories. I have an easier time understanding when I see various takes on this stuff.

Great links too.

thanks all for your links and suggestions.

Henrik

 

[boulderjohn]

I haven't read "Deco for Divers" but you'll find ALOT of information/descriptions out there which inaccurately describe the oxygen window. Many of them perpetuated by the "DIR" agencies. Stuff about milk trucks carting away N2 after they offload O2.

In actual practical practice the "O2 window" is a very large reduction in an inert creating an offgassing gradient without any lowering of absolute pressure by ascending. There's a miniscule increase in offgassing created by the metabolic consumption of O2 as described by Dr. Deco in the 2004 thread.

Yes the "O2 window" can't get any bigger than breathing 100%.

But take a switch from 21/35 to EAN50 at 70ft after a 150ft dive. There's actually an increase in N2 so that's only minimally offgassing that because you've ascended from 150ft. But there's a massive 35% reduction in helium from the gas switch so rather than the piddly offgassing you've accomplished so far by ascending from 5.5ata to 3ata you suddenly have a massive helium gradient due to the replacement of He by O2.

Except that a large number of tech divers don't agree with much/any/all of what GUE may or may not have to say

OK, this topic has bugged me for quite some time, and I can't seem to find anything that helps me understand this. I have tried over the years to raise the topic on several forums, but, to use U2's terminology, I still haven't found what I'm looking for.

I have read Deco for Divers. I have consulted DAN. I have started threads in the Ask Dr. Decompression forum to no avail. I have read all the past threads in the Ask Dr. Decompression forum. As a consequence, I have a whole pile of contradictory information that makes no sense when I try to put it all together.

I am told that I must extend my stops at 70 feet and 60 feet when switching to EANx 50 to make use of the pure magic of the oxygen window. People who don't agree with it (including Mark Powell) say I should not be doing it because the harm I am doing in N2 on-gassing more than makes up for any teensy gain I will get through the O2 vacancy effect.

It is very frustrating when you are trying to do the right thing and realize that you are just a pawn in someone's grand experiment in deco theory.

 

[PfcAJ]

The issue with a lot of deco theory is that there are not a lot of real scientific tests to back up some of it (like s-curves vs linear vs exponential, o2 window, deep stops, variable ascent rates, etc) so its hard to make an official recommendation.

I'm not above experimenting a little. For me, deeper stops with a variable ascent rate with extended stop times when I switch gas works very well. No chamber rides yet, and I usually feel like a champ after deep dives.

 

[liuk3]

If you liked Deco for Divers and want more detailed literature, I believe that he lists his source documents in the book for you to be able to followup and further research as well.

 

[rjack321]

OK, this topic has bugged me for quite some time, and I can't seem to find anything that helps me understand this. I have tried over the years to raise the topic on several forums, but, to use U2's terminology, I still haven't found what I'm looking for.

I have read Deco for Divers. I have consulted DAN. I have started threads in the Ask Dr. Decompression forum to no avail. I have read all the past threads in the Ask Dr. Decompression forum. As a consequence, I have a whole pile of contradictory information that makes no sense when I try to put it all together.

I am told that I must extend my stops at 70 feet and 60 feet when switching to EANx 50 to make use of the pure magic of the oxygen window. People who don't agree with it (including Mark Powell) say I should not be doing it because the harm I am doing in N2 on-gassing more than makes up for any teensy gain I will get through the O2 vacancy effect.

It is very frustrating when you are trying to do the right thing and realize that you are just a pawn in someone's grand experiment in deco theory.

First off if you aren't keen on being part of a grand human experiment you should probably quit diving, or at least deco diving.

Of course there's contradictory information, its applied science.

Yes you are (still) on-gassing in some parts of your body after the 70ft switch to EAN50 but you are also off-gassing in others. On some profiles EAN50 and substantively extending the O2 window makes no sense (e.g. 40min dive to 110ft on 25/25) On other profiles you'd be a fool to rush on by (e.g. after 240ft for 30mins on 15/55). It all depends on what you've done before and which "compartments" are saturated, which aren't, and with which inert. And bending some compartments will kill you alot faster than bending other compartments.

So net, many people extend the 70ft stop to assist with offgassing fast neuro compartments and are willing to accept that some slower compartments like fat and tendons may still have a net gain of N2 from this time. Those minor increased slow tissue debts aren't very difficult to repay later on O2 or just extending the 30-20-10ft stops.

As long as you do the time "somewhere" reasonable it seems to work and there aren't enough (any?) good biomarkers of sub-symptomatic DCS to try to figure out which shape is "better".