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Hello Everyone,

I have been reading this list for a few months now.  This is my first
posting to this list. (please be gentle)

First a little about myself,  I still consider my self a baby diver. I have
been diving for 11 years.  My most recent certification is as a Commercial
HSE Surface Supplied (Top Up) diver (Part 1 equivalent)  I got back from Ft.
Bovisand, Plymouth England only four months ago.  I do not consider myself a
Tech Diver yet, but I am learning. My personal focus is on wreck diving and
not cave diving.

I have been very interested in the DIR methodology.  Its practitioners seem
devoted, if not fanatical, about safety, and the furtherance of diving
technique.

With that said, I would like to open for discussion a possible alteration to
the standard DIR method.  I DO NOT currently dive with this rigging method,
but am considering it. I would like your input and suggestions.



While in England I was introduced to the idea of mounting your tanks so that
the valves were mounted on the bottom. (near your butt).  At first I
dismissed this as being silly.  But after a proper introduction to the
reasoning behind it, I think it has some possible advantages.

One of my own concerns with this arrangement is that with the tanks being
upside down, any particulate matter in the tanks would head straight for the
valves.  (this shouldn't be a problem with properly inspected, and
maintained tanks, but still...)

The first possible advantage is that the valves are much easier to reach.
If you can scratch your butt you can turn a valve.  This comes in especially
handy for doubles with an isolation manifold.

A second possible advantage.  When using round bottom (now top) tanks, you
are even more streamlined, and have greater clearance around your head.
It's easier to look up or forward with NO obstructions behind your head.

A third possible advantage. Your manifold is less likely to get banged
during a "Push" though an overhead environment.


And here is a big one for the Remove all excess potential failure points
fans:

The Royal navy divers do not use a pressure gauge. That's one less hose.
They employ an interesting method of gas management.

1- They start with two full tanks Isolated.
One on, one off

2- They breath the first tank to empty,
then open the second tank
The tanks then equalize so each tank is now at %50 capacity.
They then shut off the second tank, isolating it.

3- They breath the first tank to empty again,
They then open the second tank
The tanks then equalize so each tank is now at %25 capacity.
This is the reserve point, so begin ascent procedures.

I'm not sure I would want to dive without an SPG, but in this configuration
the hose length could at least be dramatically reduced.



-- Finally my questions.

First, what is your opinion on this upside down idea?

Second, how do you see this would effect the long hose, and other hose
routings?

- Craig Waldman
    New Jersey
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