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Allyson,

Please explain the significance of the number of theoretical compartments=20
either on-gassing or off-gassing, verses the one theoretical compartment tha=
t=20
happens to be controlling the deco at any one particular time.

Karl



In a message dated 8/28/00 12:15:12 PM, AllysonClagett writes:
<< Hi Karl,

I ran your 80/20 ("stroke mix") numbers on decoplanner and would get out of=20
the water 3 minutes faster than using the DIR deco gases.  I found that you=20
do get out of the water faster, however, you get out having on-gased a lot=20
more Nitrogen.

I am addressing the issue of Nitrogen here, I haven't enough education on th=
e=20
matter to speak of anything else.

Let me just say, that, the goal of decompressing is to do it efficiently.=20
Efficiently, meaning one should accelerate the elimination of the inert=20
gasses (Nitrogen and Helium) in his "fast loading tissue compartments" while=
=20
minimizing the on gassing in his "slow loading tissue compartments."  If he=20
doesn't decompress efficiently he may feel tired and down right lethargic=20
after his dives.

If you compare your "dive" to 200 feet on 18/35 for 30 min, then deco-ing on=
=20
EAN 36 @ 110ft, then EAN 80 @ 30 ft to the DIR method of deco-ing (EAN50 @ 7=
0=20
feet, 100 OXYGEN @20 feet) you will notice that the DIR method is more=20
efficient.  (Hit the "analyse" button after you plan the dives.)

At 110 feet when you would switch to your EAN 36 you are now on-gassing=20
Nitrogen in 13 of your tissue compartments whereas on your bottom mix you=20
were ongassing in only 11 of your tissue compartments.  Your deco gas would=20
have you on-gassing more Nitrogen than your bottom mix. =20

Using the deco plan (80/20) that gets you out of the water faster has your=20
tissue compartments on-gassing more Nitrogen than the (DIR) method through=20
all segments of the dive.   Except at segment 21 (where you ascend from 40 t=
o=20
30 feet) you are now off-gassing Nitrogen in all your tissue compartments bu=
t=20
it does not make up for all the extra on-gassing you did during your dive up=
=20
to this point.  At segment 21 the DIR deco is off-gassing in all but 3=20
compartments=85in 10 more ft they too will be off- gassing in all compartmen=
ts=20
and off-gassing a lot more Nitrogen than the deeper deco stop using 80/20.=20

This is one of the reasons why the DIR plan is the way to go, to efficiently=
=20
off gas the Nitrogen.   =20

Allyson Clagett




In a message dated 08/26/2000 4:40:02 AM Eastern Daylight Time,=20
KRussellTX@ao*.co* writes:

<< I have been reading in this group how 80/20 is not the gas to use
for=20
deco. =20
 I have also been reading that Decoplanner is great and EAN50 @ 70 ft. and=20
100=20
 % oxygen at 20 ft. is the DIR way to go.  In truth I haven't got the=20
 slightest idea what the "oxygen window" means unless it simply refers to=20
 using the closest PO2 that is below 1.6 that you can get to.
=20
 Now the question I have to ask is that if 80/20 is only used by strokes, wh=
y=20
 is it that on a dive to 200 ft. on 18/35 for 30 minutes, doing a deco using=
=20
 EAN 36 @ 110 ft. and EAN 80 @ 30 ft. actually results in a shorter deco tha=
n=20
 EAN50 @ 70 ft. and 100% oxygen @ 20 ft.?
=20
 Any explanations why the stroke mix seems to get you out of the water soone=
r?
=20
 K. Russell >> >>

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