On Friday, October 19, 2001 7:21 PM, Christian Gerzner wrote:

> > Check out the "how to invert your twins if you're off the errr ....
"husky"
> > type of physical build  http://www.divernet.com/gear/invert1198.htm

(Big snip)

> As Phi Lee quite correctly pointed out (but possibly too briefly):

> > I believe it is the system used by S&R people when diving in *ZERO*
> > visibility where a SPG is useless.

> Whilst this bloke may not (even) get that part of his diving right,
> his comments have some merit.

> Without going to the site I suspect (DON'T know) that he's talking of
> many emergency/military diving organisations. These commonly work in
> visually impenetrable water and use this technique, also commonly,
> with (in our eyes) "back to front" cylinders, probably specially
> designed ones (Strike, you want to embellish?) and manifolds. It's,
> quite literally, the ONLY way that they can manage their gas.

He's based his configuration on the SABA (Swimmers Air Breathing Apparatus)
set, a twin-hose set up that was specifically designed  - with appropriate
plumbing - to be used in that fashion and that came into service in, I
believe, about 1963!  :-).

It was a good, sturdy unit - and purpose built to be both sailor-proof, (the
highest rating that any equipment can have? <BWG>), and function in zero
visibility where the user couldn't/wouldn't want to be bothered with
inconsequential things like periodically checking an SPG while his hands
were filled with other things!  :-)

(The really nice thing about the SABA  - or 'Man-On-The-Moon' sets, as they
were generally known - was their versatility.  The cylinders could be filled
manually - if you were an idiot like me - using a hand-pump!)  :-)

However!   (And while I agree that  in certain situations there are merits
to using inverted cylinders), I do believe that configuration is everything.
i.e. If the entire unit isn't purpose-designed for the way that it will be
used, then it ain't a good system!  :-)

Adaptation is OK providing it doesn't mean inventing a square wheel! And in
the system that the guy in the picture is using, he's inventing a square
wheel! :-)

Strike


----- Original Message -----
From: Christian Gerzner <christiang@cc*.co*.au*>
To: Tech diver list <techdiver@aquanaut.com>
Sent: Friday, October 19, 2001 7:21 PM
Subject: Re: 300m coffee maker


> Dean, and list,
>
> Dean Laffan wrote:
> (snips)
>
> > Wow, this site has some pretty amazing crap.
> >
> > Check out the "how to invert your twins if you're off the errr ....
"husky"
> > type of physical build  http://www.divernet.com/gear/invert1198.htm
> >
> > Here's a snippet of the accompanying text:
> >
> > > a very simple scuba system that consists of a twinset with manifold,
one first
> > > and one second stage and no contents gauge at all. They simply shut
off one
> > > cylinder pillar valve, then breathe off the other one until it is
nearly empty
> > > and they sense an increasing breathing resistance.
> > > That is when they reach behind them, open the previously closed pillar
valve
> > > and decant air from the full cylinder to the empty one. They then shut
off the
> > > "donor" cylinder again. This decanting process is carried out twice.
Then,
> > > with 50 bars left in each cylinder (from an initial 200 bar fill), it
is time
> > > to head back to the surface.
>
> As Phi Lee quite correctly pointed out (but possibly too briefly):
>
> > I believe it is the system used by S&R people when diving in *ZERO*
> > visibility where a SPG is useless.
>
> Whilst this bloke may not (even) get that part of his diving right,
> his comments have some merit.
>
> Without going to the site I suspect (DON'T know) that he's talking of
> many emergency/military diving organisations. These commonly work in
> visually impenetrable water and use this technique, also commonly,
> with (in our eyes) "back to front" cylinders, probably specially
> designed ones (Strike, you want to embellish?) and manifolds. It's,
> quite literally, the ONLY way that they can manage their gas.
>
> In visually impenetrable water an SPG is obviously quite useless.
>
> Dean, we have such diving units here in Oz and I immensely respect
> what they (and their colleagues all over the world) do. It's their
> job, they don't have an "opt out" choice ...  as we do.
>
> Which is not to say that all of them use this technique.
>
> Cheers,
>
> Christian
> --
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