Ali or steel stage tanks question - perhaps a bit boring, but I'm confused.

"hyweldavies" wrote

>The DIRistas are all pretty adament that Ali's the thing, due to more
>desirable bouyancy characteristics.

Yep.

> However, I'm still unconvinced and don't want to lug an extra 2 or 3
> kilos up a ladder unless there's really a very good reason . . .

If buoyancy characteristics don't convince you, then don't. There's no
better reason.

>and they're less robust.

Not in my opinion, they aren't. BTW, aluminum tanks don't rust.

> So here's the figures from go-dive's website ():
> Luxfer ali tank 7l 9.8kg, (buoyancy stated as +1.87kg empty)
> Faber steel 7l - 8kg (presumably empty?)

Buoyancy is more of an issue when the tanks are full than when they are
empty. In order to safely dive a steel tank, at least by DIR standards, you
need sufficient buoyancy to swim it up when full and redundant buoyancy to
do the same if your primary device fails.

> Either way, 7l air @ 232 bar = 1.9kg, so I'd need an extra block of
> lead with the Ali cylinder . . .

Lead is not the issue, lift is.

Lee

"hyweldavies" wrote

>The DIRistas are all pretty adament that Ali's the thing, due to more
>desirable bouyancy characteristics.

Yep.

> However, I'm still unconvinced and don't want to lug an extra 2 or 3
> kilos up a ladder unless there's really a very good reason . . .

If buoyancy characteristics don't convince you, then don't. There's no
better reason.

>and they're less robust.

Not in my opinion, they aren't. BTW, aluminum tanks don't rust.

> So here's the figures from go-dive's website ():
> Luxfer ali tank 7l 9.8kg, (buoyancy stated as +1.87kg empty)
> Faber steel 7l - 8kg (presumably empty?)

Buoyancy is more of an issue when the tanks are full than when they are
empty. In order to safely dive a steel tank, at least by DIR standards, you
need sufficient buoyancy to swim it up when full and redundant buoyancy to
do the same if your primary device fails.

> Either way, 7l air @ 232 bar = 1.9kg, so I'd need an extra block of
> lead with the Ali cylinder . . .

Lead is not the issue, lift is.

Lee

"hyweldavies" wrote

>The DIRistas are all pretty adament that Ali's the thing, due to more
>desirable bouyancy characteristics.

Yep.

> However, I'm still unconvinced and don't want to lug an extra 2 or 3
> kilos up a ladder unless there's really a very good reason . . .

If buoyancy characteristics don't convince you, then don't. There's no
better reason.

>and they're less robust.

Not in my opinion, they aren't. BTW, aluminum tanks don't rust.

> So here's the figures from go-dive's website ():
> Luxfer ali tank 7l 9.8kg, (buoyancy stated as +1.87kg empty)
> Faber steel 7l - 8kg (presumably empty?)

Buoyancy is more of an issue when the tanks are full than when they are
empty. In order to safely dive a steel tank, at least by DIR standards, you
need sufficient buoyancy to swim it up when full and redundant buoyancy to
do the same if your primary device fails.

> Either way, 7l air @ 232 bar = 1.9kg, so I'd need an extra block of
> lead with the Ali cylinder . . .

Lead is not the issue, lift is.

Lee

"hyweldavies" wrote

>The DIRistas are all pretty adament that Ali's the thing, due to more
>desirable bouyancy characteristics.

Yep.

> However, I'm still unconvinced and don't want to lug an extra 2 or 3
> kilos up a ladder unless there's really a very good reason . . .

If buoyancy characteristics don't convince you, then don't. There's no
better reason.

>and they're less robust.

Not in my opinion, they aren't. BTW, aluminum tanks don't rust.

> So here's the figures from go-dive's website ():
> Luxfer ali tank 7l 9.8kg, (buoyancy stated as +1.87kg empty)
> Faber steel 7l - 8kg (presumably empty?)

Buoyancy is more of an issue when the tanks are full than when they are
empty. In order to safely dive a steel tank, at least by DIR standards, you
need sufficient buoyancy to swim it up when full and redundant buoyancy to
do the same if your primary device fails.

> Either way, 7l air @ 232 bar = 1.9kg, so I'd need an extra block of
> lead with the Ali cylinder . . .

Lead is not the issue, lift is.

Lee

"hyweldavies" wrote

>The DIRistas are all pretty adament that Ali's the thing, due to more
>desirable bouyancy characteristics.

Yep.

> However, I'm still unconvinced and don't want to lug an extra 2 or 3
> kilos up a ladder unless there's really a very good reason . . .

If buoyancy characteristics don't convince you, then don't. There's no
better reason.

>and they're less robust.

Not in my opinion, they aren't. BTW, aluminum tanks don't rust.

> So here's the figures from go-dive's website ():
> Luxfer ali tank 7l 9.8kg, (buoyancy stated as +1.87kg empty)
> Faber steel 7l - 8kg (presumably empty?)

Buoyancy is more of an issue when the tanks are full than when they are
empty. In order to safely dive a steel tank, at least by DIR standards, you
need sufficient buoyancy to swim it up when full and redundant buoyancy to
do the same if your primary device fails.

> Either way, 7l air @ 232 bar = 1.9kg, so I'd need an extra block of
> lead with the Ali cylinder . . .

Lead is not the issue, lift is.

Lee

"hyweldavies" wrote

>The DIRistas are all pretty adament that Ali's the thing, due to more
>desirable bouyancy characteristics.

Yep.

> However, I'm still unconvinced and don't want to lug an extra 2 or 3
> kilos up a ladder unless there's really a very good reason . . .

If buoyancy characteristics don't convince you, then don't. There's no
better reason.

>and they're less robust.

Not in my opinion, they aren't. BTW, aluminum tanks don't rust.

> So here's the figures from go-dive's website ():
> Luxfer ali tank 7l 9.8kg, (buoyancy stated as +1.87kg empty)
> Faber steel 7l - 8kg (presumably empty?)

Buoyancy is more of an issue when the tanks are full than when they are
empty. In order to safely dive a steel tank, at least by DIR standards, you
need sufficient buoyancy to swim it up when full and redundant buoyancy to
do the same if your primary device fails.

> Either way, 7l air @ 232 bar = 1.9kg, so I'd need an extra block of
> lead with the Ali cylinder . . .

Lead is not the issue, lift is.

Lee

"hyweldavies" wrote

>The DIRistas are all pretty adament that Ali's the thing, due to more
>desirable bouyancy characteristics.

Yep.

> However, I'm still unconvinced and don't want to lug an extra 2 or 3
> kilos up a ladder unless there's really a very good reason . . .

If buoyancy characteristics don't convince you, then don't. There's no
better reason.

>and they're less robust.

Not in my opinion, they aren't. BTW, aluminum tanks don't rust.

> So here's the figures from go-dive's website ():
> Luxfer ali tank 7l 9.8kg, (buoyancy stated as +1.87kg empty)
> Faber steel 7l - 8kg (presumably empty?)

Buoyancy is more of an issue when the tanks are full than when they are
empty. In order to safely dive a steel tank, at least by DIR standards, you
need sufficient buoyancy to swim it up when full and redundant buoyancy to
do the same if your primary device fails.

> Either way, 7l air @ 232 bar = 1.9kg, so I'd need an extra block of
> lead with the Ali cylinder . . .

Lead is not the issue, lift is.

Lee

On 2005-11-13, hyweldavies <hywelmodeng@yahoo.co.uk> wrote:
>
> Either way, 7l air @ 232 bar = 1.9kg, so I'd need an extra block of
> lead with the Ali cylinder, + the extra 0.8 (or 1.8kg) of the cylinder
> itself, so I'm best part of 3kg heavier climbing the ladder. Whichever
>

Don't climb the ladder with your stages on. If you don't have a diver
lift, unclip the stages on the surface and hook them onto a DSMB,
get someone on the boat to recover them, or pick them up once you're
back on board.

Luxfer redesigned the Al 7 a couple of years ago and screwed up the
buoyancy characteristics, so there is now very little difference
between a steel and a new Al. What you really want is an older
Al 7, or a US Al-80 if you can get them filled.

-- Pete

On 2005-11-13, hyweldavies <hywelmodeng@yahoo.co.uk> wrote:
>
> Either way, 7l air @ 232 bar = 1.9kg, so I'd need an extra block of
> lead with the Ali cylinder, + the extra 0.8 (or 1.8kg) of the cylinder
> itself, so I'm best part of 3kg heavier climbing the ladder. Whichever
>

Don't climb the ladder with your stages on. If you don't have a diver
lift, unclip the stages on the surface and hook them onto a DSMB,
get someone on the boat to recover them, or pick them up once you're
back on board.

Luxfer redesigned the Al 7 a couple of years ago and screwed up the
buoyancy characteristics, so there is now very little difference
between a steel and a new Al. What you really want is an older
Al 7, or a US Al-80 if you can get them filled.

-- Pete

On 2005-11-13, hyweldavies <hywelmodeng@yahoo.co.uk> wrote:
>
> Either way, 7l air @ 232 bar = 1.9kg, so I'd need an extra block of
> lead with the Ali cylinder, + the extra 0.8 (or 1.8kg) of the cylinder
> itself, so I'm best part of 3kg heavier climbing the ladder. Whichever
>

Don't climb the ladder with your stages on. If you don't have a diver
lift, unclip the stages on the surface and hook them onto a DSMB,
get someone on the boat to recover them, or pick them up once you're
back on board.

Luxfer redesigned the Al 7 a couple of years ago and screwed up the
buoyancy characteristics, so there is now very little difference
between a steel and a new Al. What you really want is an older
Al 7, or a US Al-80 if you can get them filled.

-- Pete