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IT looks like someone read the chart incorrectly.

Luxfer manufactures 3  80 (nominal) cubic foot cylinders.

standard 80      77 cuft / 3000 psi  7.25 inch diameter  26.06 inches tall 
-- 31.7 lbs empty and an empty/full bouyancy shift of +4/-1.9 lbs


compact 80      80 cuft / 3000 psi   8 inch diameter   24 inches tall --- 
32 lbs empty and an empty/full buoyancy shift of +0.7/-4.7 lbs

Neutral 80         77 cuft/3300 psi      7.251 diameter  25.81 inches 
tall  35.2 lbs empty and an empty/full buoyancy shift of 0.0/-5.8

(this tank is designed to be "neutral" when empty and not float like a cork


regards,
jds





At 05:51 PM 2/23/2001 -0800, Kevin Connell wrote:
>David, yes absolutely, 80cu ft of air weighs less than 104.     If there 
>is one thing this discussion has shown, its that the charts are total crap.
>
>
>At 08:57 PM 2/22/2001 -0800, you wrote:
>>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
>> >
>> > --
>> > Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'.
>> > Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
>>
>>
>>--
>>Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'.
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>
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Content-Type: text/html; charset="us-ascii"

<html>
<font size=3><br>
IT looks like someone read the chart incorrectly. <br>
<br>
Luxfer manufactures 3  80 (nominal) cubic foot cylinders.<br>
<br>
standard 80      77 cuft / 3000 psi  7.25
inch diameter  26.06 inches tall -- 31.7 lbs empty and an empty/full
bouyancy shift of +4/-1.9 lbs<br>
<br>
<br>
compact 80      80 cuft / 3000 psi   8
inch diameter   24 inches tall --- 32 lbs empty and an
empty/full buoyancy shift of +0.7/-4.7 lbs <br>
<br>
Neutral 80         77 cuft/3300
psi      7.251 diameter  25.81 inches
tall  35.2 lbs empty and an empty/full buoyancy shift of 0.0/-5.8
<br>
<br>
(this tank is designed to be "neutral" when empty and not float
like a cork <br>
<br>
<br>
regards, <br>
jds <br>
<br>
<br>
<br>
<br>
<br>
At 05:51 PM 2/23/2001 -0800, Kevin Connell wrote:<br>
<blockquote type=cite class=cite cite>David, yes absolutely, 80cu ft of
air weighs less than 104.     If there is one thing
this discussion has shown, its that the charts are total crap.<br>
<br>
<br>
At 08:57 PM 2/22/2001 -0800, you wrote:<br>
<blockquote type=cite class=cite cite>Guys,<br>
One of the things I see missing from your discussion is how much the
tanks<br>
buoyancy changes from full to empty. Look at the abyss tank chart and
you<br>
will see the PST 104 has a change of 4.6 lbs vs. 5.9 lbs. for the Luxfer
80<br>
(77), now double those numbers and look at the weight difference
needed.<br>
<br>
<a href="http://www.abysmal.com/pages/features-cylinders.html"
eudora="autourl">http://www.abysmal.com/pages/features-cylinders.html</a><
br>
<br>
Also from looking at this chart I'd say that the Luxfer 80's are going
to<br>
start swinging positively buoyant closer to 2000 psi than 1100 psi.
A<br>
doubles manifold may push it down some but not that much.<br>
<br>
DT<br>
<br>
<br>
<br>
><br>
><br>
> Don Burke wrote:<br>
><br>
> > From: Marv <ajmarve@ba*.ne*><br>
> ><br>
> >> ok<br>
> >> first, if you read Pauls post you should have been able to
infer that<br>
he<br>
> >> was discussing the weight of the tanks on dry land.<br>
> ><br>
> ><br>
> > The _only_ place that is true is on dry land.<br>
><br>
> um, ok?<br>
><br>
><br>
> >   For a given gas capacity, a<br>
> > diver wearing aluminum tanks is a bit heavier on the boat since
the<br>
> > displacement of the aluminum requires wearing more 
weight.<br>
><br>
><br>
> only if you breathe the tanks below approx 1100psi, the point at
which<br>
> they swing positive.<br>
><br>
> ><br>
> ><br>
> >> If you ever tried to lift a set of 104s and then right away
move a set<br>
> >> of 80's, like i do when im filling in my garage, you would
see the<br>
> >> difference between the two,<br>
> ><br>
> ><br>
> > That's comparing apples and watermelons.<br>
><br>
> Thats what i was saying, that the tanks were different. So much so
that<br>
> if dry land weight was a consideration, as Paul indicated in
his<br>
> original post, then the 80s "beat" the 104's. i never
mentioned steel<br>
> 80's and esp not hp 80s like the pst. There is no reason to bring
them<br>
> into the discussion in fact because they swim horribly. you guys
can<br>
> talk numbers all you want, try diving the tanks and then tell me
about it.<br>
><br>
> > I made up a set of AL 80s and I'm wearing 11# of lead (with a
steel<br>
plate)<br>
> > with a wetsuit in fresh water.  I haven't hit the ocean
with these yet,<br>
so<br>
> > my calculation of 17# is approximate at best.  As soon as
I go dry,<br>
those<br>
> > tanks will become deco/stage/rec bottles.  If I didn't
already own the<br>
AL<br>
> > 80s, I certainly wouldn't have bought them.<br>
> ><br>
> > Those 104s are a pretty heavy item as steel tanks go. 
They weigh about<br>
the<br>
> > same as an OMS 125.<br>
> ><br>
> > Capt JT wears a set of 104s and more power to him.  I
haven't asked him<br>
what<br>
> > he like about them.<br>
> > I have a welder and a generator I can lift when I feel the need
for a<br>
> > hernia. :)<br>
> > I think I'll go for 112s when I get to that.<br>
><br>
> the 104 is a  good choice for cave, where extra buoyancy is a
minus. one<br>
> can manage to dive them in the ocean,but i dont see them as ideal in
the<br>
> ocean.<br>
><br>
> > The wall thickness on an aluminum tank is so much greater than
that of a<br>
> > steel tank, the weight of the tank is more and the displacement
is more.<br>
><br>
> and in the water you have the wt of the valve, the gas, the reg
to<br>
> consider, along w/ all you other gear.<br>
><br>
> Marv<br>
><br>
> --<br>
> Send mail for the `techdiver' mailing list to
`techdiver@aquanaut.com'.<br>
> Send subscribe/unsubscribe requests to
`techdiver-request@aquanaut.com'.<br>
<br>
<br>
--<br>
Send mail for the `techdiver' mailing list to
`techdiver@aquanaut.com'.<br>
Send subscribe/unsubscribe requests to
`techdiver-request@aquanaut.com'.</blockquote><br>
--<br>
Send mail for the `techdiver' mailing list to
`techdiver@aquanaut.com'.<br>
Send subscribe/unsubscribe requests to
`techdiver-request@aquanaut.com'.<br>
</font></blockquote></html>

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