Hi,

Am I missing something ? How can 104CuFt of Air can weight 4.6 lbs
and 77CuFT 5.9 lbs ??

kiki

--
Huu-Nghia VUONG a.k.a. Kiki   Design and Performance Infrastructure
Actel Corporation             Timing and Power Products
955 East Arques Avenue        e-mail : kiki@ac*.co*     
Sunnyvale, CA 94086           voice  : (408) 522 4382
USA                           fax    : (408) 516 9894


> -----Original Message-----
> From: David M. Thiesfeld [mailto:dthiesfeld@su*.ne*]
> Sent: Thursday, February 22, 2001 8:58 PM
> To: Marv; Don Burke
> Cc: techdiver
> Subject: Re: DIHUL, was: Fins question
> 
> 
> Guys,
> One of the things I see missing from your discussion is how 
> much the tanks
> buoyancy changes from full to empty. Look at the abyss tank 
> chart and you
> will see the PST 104 has a change of 4.6 lbs vs. 5.9 lbs. for 
> the Luxfer 80
> (77), now double those numbers and look at the weight 
> difference needed.
> 
> http://www.abysmal.com/pages/features-cylinders.html
> 
> Also from looking at this chart I'd say that the Luxfer 80's 
> are going to
> start swinging positively buoyant closer to 2000 psi than 1100 psi. A
> doubles manifold may push it down some but not that much.
> 
> DT
> 
> 
> 
> >
> >
> > Don Burke wrote:
> >
> > > From: Marv <ajmarve@ba*.ne*>
> > >
> > >> ok
> > >> first, if you read Pauls post you should have been able 
> to infer that
> he
> > >> was discussing the weight of the tanks on dry land.
> > >
> > >
> > > The _only_ place that is true is on dry land.
> >
> > um, ok?
> >
> >
> > >   For a given gas capacity, a
> > > diver wearing aluminum tanks is a bit heavier on the boat 
> since the
> > > displacement of the aluminum requires wearing more weight.
> >
> >
> > only if you breathe the tanks below approx 1100psi, the 
> point at which
> > they swing positive.
> >
> > >
> > >
> > >> If you ever tried to lift a set of 104s and then right 
> away move a set
> > >> of 80's, like i do when im filling in my garage, you 
> would see the
> > >> difference between the two,
> > >
> > >
> > > That's comparing apples and watermelons.
> >
> > Thats what i was saying, that the tanks were different. So 
> much so that
> > if dry land weight was a consideration, as Paul indicated in his
> > original post, then the 80s "beat" the 104's. i never 
> mentioned steel
> > 80's and esp not hp 80s like the pst. There is no reason to 
> bring them
> > into the discussion in fact because they swim horribly. you guys can
> > talk numbers all you want, try diving the tanks and then 
> tell me about it.
> >
> > > I made up a set of AL 80s and I'm wearing 11# of lead 
> (with a steel
> plate)
> > > with a wetsuit in fresh water.  I haven't hit the ocean 
> with these yet,
> so
> > > my calculation of 17# is approximate at best.  As soon as 
> I go dry,
> those
> > > tanks will become deco/stage/rec bottles.  If I didn't 
> already own the
> AL
> > > 80s, I certainly wouldn't have bought them.
> > >
> > > Those 104s are a pretty heavy item as steel tanks go.  
> They weigh about
> the
> > > same as an OMS 125.
> > >
> > > Capt JT wears a set of 104s and more power to him.  I 
> haven't asked him
> what
> > > he like about them.
> > > I have a welder and a generator I can lift when I feel 
> the need for a
> > > hernia. :)
> > > I think I'll go for 112s when I get to that.
> >
> > the 104 is a  good choice for cave, where extra buoyancy is 
> a minus. one
> > can manage to dive them in the ocean,but i dont see them as 
> ideal in the
> > ocean.
> >
> > > The wall thickness on an aluminum tank is so much greater 
> than that of a
> > > steel tank, the weight of the tank is more and the 
> displacement is more.
> >
> > and in the water you have the wt of the valve, the gas, the reg to
> > consider, along w/ all you other gear.
> >
> > Marv
> >
> > --
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> `techdiver@aquanaut.com'.
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> `techdiver-request@aquanaut.com'.
> 
> 
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