George
First under all circumstances possible divers are to remain intact sharing
gas, through restrictions etc. In fact when I and I imagine other cave
instructors teach gas sharing we have students share gas through
restrictions. One of my favorites is the half hitch in Madison. Another one
is the restriction in the Gonzalla room tunnel and a third is the
restriction coming out of devils eye. In all these normal gas sharing is
performed right through the restrictions I usually do a few restriceion gas
sharing drills with the divers sharing gas at all times.


SECOND IN THE EVENT THERE IS SUCH A MAJOR And Complex RESTRICTION
ENCOUNTERED THAT THE DIVERS CANNOT GET THROUGH IT WHILE SHARING GAS, a
situation exist that they must separate in order to get to a point where it
is possible to share gas again, the procedure of having the donor allow the
out of air diver to get several deep slow breaths and become as calm as
possible before the temporary interruption of the act of gas sharing due to
the nature of the MAJOR restriction (remember this is a worse case scenario
not the average restriction, this is a very major restriction event, making
it virtually impossible to continue sharing gas and still be able to exit
the cave.) it was felt that if one diver had to lead through such a
restriction the donor should, as the out of air diver could relax and see
that the air supply was infront of him/her not behind,
The donor will at the earliest point where it is possible to get the second
stage /long hose to the diver signals the out of air diver to come and get
the gas the diver then swims towards the air supply and gets it.

Hopefully most divers will not be in areas that have such major complex
restrictions, but the process was developed so that there would be a
predetermined plan of action on how to handle such a drastic situation
should it occur. The other choice would be that in such a situation the
diver out of air goes first which means he begins to exert, then exit the
restriction and have to turn facing back into the restriction to get air,
that is more difficult and stressful than the first option.

A third approach of course is do not teach anything for this worse case
scenario and if it happens to a dive team let them figure it out on their
own, under stress without having the benefit of a dry rehearsal or thoughts
as to how to address such a possibility.

What prompted the development of this drill was from early blue hole
explorations where we did have restrictions that made it virtually
impossible to share gas through so this drill was introduced for a worse
case scenario, not a routine gas sharing exercise for all restrictions.

Now for those of you who mistakenly assumed that this was a procedure for
any restriction hopefully you now know better. Maybe you would like to
comment then on
1. Should this remote what if situation be taught
2. Should this type situation not be addressed and just let the divers who
may face this situation someday figure it out under a real situation instead
of a simple training exercise for a worse case scenario, which is how it is
descried. And practiced.

To summarize all students are taught to remain actively sharing gas (in an
out of air situation) under any condition where it is possible to do so.
They are then exposed to a worse case scenario where a restriction is so
major and complex that it is impossible to go through it in a gas sharing
mode thus this is a alternative that will work.  Students are also taught if
possible that gas sharing should start with a little gas left in the
cylinders in event of such a situation, but again the most serious situation
we can imagine must also be at least introduced to the student.



Respectfully yours,
Tom Mount
CEO IANTD World HQ
http://www.iantd.com

-----Original Message-----
From: Richard Pyle <deepreef@bi*.or*>
To: kirvine@sa*.ne* <kirvine@sa*.ne*>
Cc: cavers@ca*.co* <cavers@ca*.co*>; Randylabel@ao*.co*
<Randylabel@ao*.co*>; rebreather@nw*.co* <rebreather@nw*.co*>
Date: Tuesday, November 10, 1998 8:12 AM

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