Spare Air

Views please on application and value of spare cylinder smaller than 3 ltr
(0.4ltr?) believe these are available with a regulator attached directly to
bottle.

Thanks
Ken Ward

"Ken Ward" <ken.ward@btinternet.com> wrote in message
news:buhk2m$37u$1@hercules.btinternet.com...
> Views please on application and value of spare cylinder smaller than 3 ltr
> (0.4ltr?) believe these are available with a regulator attached directly
to
> bottle.

In a nutshell, don't even bother - they're a joke, pure and simple!!!! If
you want redundancy then go for a pony bottle and reg setup - it'll give you
more than a couple of breaths (which is about all you'd get out of a spare
air!) and the price isn't that much different! In my opinion, the Spare Air
shouldn't be touched with a barge pole!!!!!!!!

I'd be *very* surprised if you find a single person in this newsgroup that
has one positive thing to say about them...

Ken Ward wrote:
> Views please on application and value of spare cylinder smaller than
> 3 ltr (0.4ltr?) believe these are available with a regulator attached
> directly to bottle.

I attract a lot of flak by defending the 3L pony
against its detractors but even I can't make a
case for 0.4L

I fear that the deployment time will not pay you
back. I think they were designed for downed
helicopter exits and they have enough for a
duck dive and escape at the surface but depth
just eats into volume.

They might be good but not good enough to be
cost effective.

nigelH

On Mon, 19 Jan 2004 22:00:54 +0000 (UTC), "Ken Ward"
<ken.ward@btinternet.com> wrote:

>Views please on application and value of spare cylinder smaller than 3 ltr
>(0.4ltr?) believe these are available with a regulator attached directly to
>bottle.
>
Don't do it. Don't go there.

Is this a troll?

Although on second thoughts, a spare air for the breather may just be
viable.

0.4 litres @ 200 bar, that's 80 litres of gas. My normal O2
consumption is 30 bar per hour out of a 3 litre, or 1.5 litres a
minute. So a spare air full of O2 on the breather would last about 60
minutes. A miracle, a use for a spare air.

So the real question needs to be "Do they do an O2 clean version?"

Pete S.

>
> So the real question needs to be "Do they do an O2 clean version?"
>
> Pete S.

No but they do do a Nitrox version though that is OK for 40% so using it
semiclosed with 40% means you wouldnt need to do a 1 in 3 dump on the loop
which means you may get a half decent amount of time out of one.

Ken Ward wrote:
> Views please on application and value of spare cylinder smaller than
> 3 ltr (0.4ltr?) believe these are available with a regulator attached
> directly to bottle.

They are, at best, marginally useful and, considering how much they cost,
not a good value.

Lee

"Ken Ward" <ken.ward@btinternet.com> wrote in message news:<buhk2m$37u$1@hercules.btinternet.com>...
> Views please on application and value of spare cylinder smaller than 3 ltr
> (0.4ltr?) believe these are available with a regulator attached directly to
> bottle.
>
> Thanks
> Ken Ward

http://diveweb.oneandoneis2.com/spareair.htm

On Mon, 19 Jan 2004 22:00:54 +0000 (UTC), "Ken Ward"
<ken.ward@btinternet.com> wrote:

>Views please on application and value of spare cylinder smaller than 3 ltr
>(0.4ltr?) believe these are available with a regulator attached directly to
>bottle.
>

0.4 * 207 bar litres at 20 L per minute surface at say 20m depth gives
you a grand total of 82 seconds of bail out. Add in a bit of stress
and your breathing rate is likely to double or more so your down to
something like half a minute of bailout.

How much use is that ?

"Pete Melbourne" <psmvsl@yahoo.co.uk> wrote in message
news:gerp00l903pllli7ror6rkiefudn50i985@4ax.com...
> On Mon, 19 Jan 2004 22:00:54 +0000 (UTC), "Ken Ward"
> <ken.ward@btinternet.com> wrote:
>
> >Views please on application and value of spare cylinder smaller than 3
ltr
> >(0.4ltr?) believe these are available with a regulator attached directly
to
> >bottle.
> >
>
> 0.4 * 207 bar litres at 20 L per minute surface at say 20m depth gives
> you a grand total of 82 seconds of bail out. Add in a bit of stress
> and your breathing rate is likely to double or more so your down to
> something like half a minute of bailout.
>
> How much use is that ?
>
>

My sums (assuming 5l lungs, 9m/min ascent rate and 3 breaths per minute,
first breath from bottle @ 30m) reckon you will run out of that bottle when
you try to take a breath at 18m.

That is still a long way from the waves.

From 21m you will mathematically make it to the surface... just.

Sod it...

Here's the working...

Surface Surface
Volume Volume Pressure
Depth Required Left Left
----- -------- ------- --------
30m 20l 60l 150Bar
27m 18.5l 41.5l 103Bar
24m 17l 24.5l 61.25Bar
21m 15.5l 9l 22.5Bar
18m 14l Oooops!

and for 21m...

Surface Surface
Volume Volume Pressure
Depth Required Left Left
----- -------- ------- --------
21m 15.5l 64.5l 161.25Bar
18m 14l 50.5l 126.25Bar
15m 12.5l 38l 95Bar
12m 11l 27l 67.5Bar
9m 9.5l 17.5l 43.75Bar
6m 8l 9.5l 23.75Bar
3m 6.5l 3l 16.25Bar
0m 5l

CAS
--
Well, we've done it... report will follow shortly at
http://divesite.calumscott.me.uk/ukrs/rescue_diver_2004
Temperature @ Stoney? Find it or share it @
http://stoneytemps.calumscott.me.uk/

"CAS" <calumscottTAKETHISBITOUT@yahoo.com> wrote in message

> My sums (assuming 5l lungs, 9m/min ascent rate and 3 breaths per minute,
> first breath from bottle @ 30m)

And assuming that the regulator on a spare air will deliver at 30m