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Date: Fri, 01 Sep 2000 09:24:54 -0400
From: Guy Morin <xnet@vi*.ca*>
Subject: Re: 80/20 deco
To: Jim Cobb <cobber@ci*.co*>
Cc: Tech Diver <techdiver@aquanaut.com>

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Hi Jim,

Thank you Jim for confirming what was elucidated
in the post. For myself, you are quite right that I will
be using the theoretical model since it has a good
track record, and consistently estimates what I am
actually diving. Doesn't the WKPP have something
in regard to diving to what is planned? I would have
to guess not, since they never dive what they plan.

Only a fool would dive following the WKPP method
without knowing all the details of what they practice,
and that certainly isn't available on the net, on this list,
or through word of mouth.

As far as your practice versus theory, well that part
is going to be ignored the WKPP obviously hasn't
put in the same effort in 36/80 deco as it has in 50/100.

On another note, remember that it is someone who was
promulgating the WKPP method as being superior that
pointed out the tissue loading from the theoretical model,
not me. Let's keep that little detail in mind, shall we? He
who lives by the sword...

Finally, I will point out that from a logistical and consumables
perspective, 50/100 deco does make better use of resources.
If I was wanting to get hundreds of divers through the water
to stage a big push, that would be my choice too. The major
costs for a large operation is gas consumables. Using 36/80
deco requires a greater investment in blending, and gas
matching, and wastes a lot of gas. The reasons are obvious,
getting off back gas at around 100' prevents the back gas
from getting drained as would be the case in 50/100 deco.
Using back gas in deco allows it to be drained following more
liberal rules than thirds. In addition, since shallow deco allows
switching to back gas, that makes further use of back gas,
and economizes the O2. Using O2 is simple to blend, and
is insensitive to error. Since a lot of time is spent at the
shallow stops, not having to blend huge volumes of gas,
and the subsequent analysis required, and schedule tweaking,
it makes a lot of sense, especially on that scale.

So, from an operational standpoint, 50/100 is by far the best
choice. For the diver who doesn't have to worry about consuming
millions of cubic feet per year, and who wants accurate deco
estimation in a field environment that often does not afford
the luxury of a decompression chamber, something more "consistent"
makes a lot of sense.


--
Guy



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<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
<html>
Hi Jim,
<p>Thank you Jim for confirming what was elucidated
<br>in the post. For myself, you are quite right that I will
<br>be using the theoretical model since it has a good
<br>track record, and consistently estimates what I am
<br>actually diving. Doesn't the WKPP have something
<br>in regard to diving to what is planned? I would have
<br>to guess not, since they never dive what they plan.
<p>Only a fool would dive following the WKPP method
<br>without knowing all the details of what they practice,
<br>and that certainly isn't available on the net, on this list,
<br>or through word of mouth.
<p>As far as your practice versus theory, well that part
<br>is going to be ignored the WKPP obviously hasn't
<br>put in the same effort in 36/80 deco as it has in 50/100.
<p>On another note, remember that it is someone who was
<br>promulgating the WKPP method as being superior that
<br>pointed out the tissue loading from the theoretical model,
<br>not me. Let's keep that little detail in mind, shall we? He
<br>who lives by the sword...
<p>Finally, I will point out that from a logistical and consumables
<br>perspective, 50/100 deco does make better use of resources.
<br>If I was wanting to get hundreds of divers through the water
<br>to stage a big push, that would be my choice too. The major
<br>costs for a large operation is gas consumables. Using 36/80
<br>deco requires a greater investment in blending, and gas
<br>matching, and wastes a lot of gas. The reasons are obvious,
<br>getting off back gas at around 100' prevents the back gas
<br>from getting drained as would be the case in 50/100 deco.
<br>Using back gas in deco allows it to be drained following more
<br>liberal rules than thirds. In addition, since shallow deco allows
<br>switching to back gas, that makes further use of back gas,
<br>and economizes the O2. Using O2 is simple to blend, and
<br>is insensitive to error. Since a lot of time is spent at the
<br>shallow stops, not having to blend huge volumes of gas,
<br>and the subsequent analysis required, and schedule tweaking,
<br>it makes a lot of sense, especially on that scale.
<p>So, from an operational standpoint, 50/100 is by far the best
<br>choice. For the diver who doesn't have to worry about consuming
<br>millions of cubic feet per year, and who wants accurate deco
<br>estimation in a field environment that often does not afford
<br>the luxury of a decompression chamber, something more "consistent"
<br>makes a lot of sense.
<br> 
<pre>-- 
Guy</pre>
 </html>

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