The great Spare Air / SpareAir topic

[sumguy]

Rodale's says they've successfully ascended from 130 feet on a single 3.0 cf Spare Air, in tests...

...but, I wouldn't want to try it in the real world. I'm not as strongly against them as many on this board, but a pony set up isn't much more money, and seems like it would be a lot safer.

If you're determined to buy a Spare Air, and want to know the best way to use it, why not experiment? Go down to 130 feet, take out your 2nd stage, take a breath from your Spare Air, and see how far you can ascend, while blowing bubbles, and not exceeding 60 fpm? 30 fpm would be better. Then, see if there's another breath in the Spare Air, and do it again. Who knows? Maybe it can be done, in a simulated OOA situation. But, in a genuine OOA at 130 feet, that first breath might be bigger than expected.

For myself, I wouldn't trust a Spare Air to get me to the surface from any deeper than 60' or so, and would plan on doing a CESA for the last 30. But, I still think a pony is better.

Just my own opinion; and we all know what they say about those.

 

[ymy]

Sumguy,

You are correct. Spare Air is expensive and other alternate air is certainly cheaper. Like you I have no big feelings one way or the other.

I have sort of simulated what you suggested in the past, not with spare air and not from a 130 feet. What I did was in a 15 foot pool. I took a breath from my reg. Ditched my BCD/tank etc. Kept my weights and finned horizontally and then up while slowly exhaling all the while. I found I could relatively easily swim the width of the pool (25m) and the 15 foot ascent which I figure gives me a good 90+ feet on a single breath. True, it is not quite the same a swimming up, but if anything it may be a worse case as the air is not expanding as I swim horizontally. Anyway it gives me confidence should I ever run out of air at 100+ feet.

This leads me to what I don't see as the big fuss with spare air is. If it were cheaper, I certainly think it would be something I would be interested in.

 

[sumguy]

Ymy,
What was your speed when swimming horizontally? We did a similar (shorter) drill in our PADI OW class, to simulate a CESA from 30 feet. And we had a full breath. It just seems to me that in a true OOA, you may have to ascend with less than a full breath. And of course, there isn't much air for a safety stop; though, I'd rather be bent than not reach the surface. (Knock on wood).
For me, I think a Spare Air is better than no air, unless it gives you a false sense of security and causes you to do something careless. Still, I have no plans to buy one, but do plan on buying a pony bottle.

 

[Dryglove]

Me personally i dive with a pony.I figure if you blow a hose or run out of air for some reason your gonna be stressed enough as it is.Why compound that with using spare air wondering if your gonna make it to the surface without running out of air.To me why chance dcs or lung expansion cause your trying to stretch your air with a spare air.With my pony i can easily make a descent from a 100ft nice and slow and still make a safety stop.I researched spare air and for diving under 60ft id say yea its cool.But for a little more money you can have the comfort of a pony.

 

[tomcat]

Within the context of ymy's question, i think people who say that using Spare Air is a joke or could result in getting you killed, are inherently biased and should try to understand that this is not about choosing between Spare Air and other alternatives (e.g. pony).

The question here is: IF you only had a Spare Air canister with you, what is the best way to use it? Although this is never supposed to happen, if for some reason I am at 130 ft, lost my buddy and ran out of air except for a canister of Spare Air in my bc, I don't think the correct answer is "I'm too stupid to live cos I bought a Spare Air instead of a pony, think I deserve to die and hence I'll just not use it".

Bottom line is, Spare Air is better than no air. Not everybody can lug a pony around on dives (especially on flights or packaged tours) and a Spare Air may be the most practical alternative to having a pony and leaving it at home because it is too heavy or inconvienient to carry around. If you were stranded at 130 ft with no more air, no buddy and no Spare Air, I bet you're gonna do a CESA anyway!

So, with that aside, let's get back to the original question of how to make the best of what you have: 3 cu ft of air at 130 ft. E.g. breathe as late into the ascent as possible (so as to maximise number of breathes available), or it doesn't matter, just breathe normally until it runs out, then continue with CESA, or what?

 

[sumguy]

Oh, yeah. The original question.

I would think the best way would be to ascend as much as possible before your first breath from the Spare Air, take as small a breath as possible, and continue your ascent as far as you can before your next breath. It's possible that as you ascend, more air would become available in your main cylinder, so I would probably try breathing on that, as well. At 20 feet, I would breathe the Spare Air dry, trying to maximize a safety stop, before doing a CESA to the surface.
It seems I read somewhere that an average diver breathes 0.6 cu ft. of gas per minute at the surface. So, a Spare Air might last 5 minutes there, or 1 minute at 132 feet. (Hope I'm not forgeting anything; it's late) Seems like one breath at 132 feet could get you to 100 feet, where another breath could get you to 66 feet, etc. Don't know for sure if that math works in the real world, or not.

$.02

 

[Uncle Pug]

Originally posted by tomcat
if for some reason I am at 130 ft, lost my buddy and ran out of air except for a canister of Spare Air in my bc, I don't think the correct answer is "I'm too stupid to live cos I bought a Spare Air instead of a pony, think I deserve to die and hence I'll just not use it".


So, with that aside, let's get back to the original question of how to make the best of what you have: 3 cu ft of air at 130 ft.

OK... tomcat... I think I see the premise now...

If I am stupid enough to run out of air at 130 ft. (not to mention using air at 130 ft.) and stupid enough not to have a buddy handy... then I would be stupid enough to think that a Spare Air is a good idea... but not really bright enough to figure out how to use it.

Did I get it right???

 

[Uncle Pug]

Originally posted by sumguy
For me, I think a Spare Air is better than no air, unless it gives you a false sense of security and causes you to do something careless.

The purchase of a Spare Air is the first huge step down the road of false security... once purchased it must be carried and its use defended...

Only a fool (not you sumguy) would deny that a Spare Air does not impart some sense of security... that is why it is purchased after all... as a mitigation for all the terrifying *what ifs*....

It is the refusal to face the *what ifs* and mitigate them correctly that puts divers at risk... and it is *safety* items like the Spare Air that aid them in their folly...

Of course this is all just my opinion...

btw: For me, I think a towel is better than no parachute, unless it gives you a false sense of security and causes you to do something careless - like jump out of plane without a parachute.

 

[landlocked]

Although I find myself reading a serious topic, I find myself being wonderfully entertained!

OK, my thoughts (which aren't worth much.)

If I am stupid enough to run out of air at 130 ft. (not to mention using air at 130 ft.) and stupid enough not to have a buddy handy... Uncle Pug

You just have to agree with what UP is saying. Don't run out of air and use your buddy. If your diving at a 130 feet (strictly theory for this new guy) spare air has no business on the equipment list. An emergency ascent from that depth has got to hurt if you get there at all! And 3 cubic feet is not going to help much. Other precautions need to be taken.

I would think the best way would be to ascend as much as possible before your first breath from the Spare Air, take as small a breath as possible, and continue your ascent as far as you can before your next breath. .......... At 20 feet, I would breathe the Spare Air dry, trying to maximize a safety stop, before doing a CESA to the surface......... So, a Spare Air might last 5 minutes there, or 1 minute at 132 feet. Seems like one breath at 132 feet could get you to 100 feet, where another breath could get you to 66 feet, etc.... sumguy

Not sure what a CESA is. However, if you were out of air at 130 feet any ascent which will get you to the surface with or without a spare air would have to involve ditching the weights and hoping for the best. That being the case, stopping at 20 to suck down the Spare Air would seem impossible!

I've decided to use mine to auto-inflate my "girlfriend". Tired of 20 minutes of huffing on that little valve just to have a "date" for the night.

Vulgar, but I have to admit, It got me laughing! (Did SpyderTek just tell the whole world what I think he did? Funny, but his profile looks like he should be able to do a little better.)

My conclusion. Don't run out of air and use your buddy. It would seem to me that if you are deep enough and long enough to where you still need more comfort, you are well into the realm of doubles. Along that same line, if you don't have a buddy you are also using doubles or diving very shallow (read pool.) (To me, it dosen't seem prudent to dive solo any other way.) Best way to use spare air? A depths shallow enough that you don't need one and/or the surface is faster than swimming to your buddy. Maybe 40 feet max if your not down too long? So whats the point of spending the money?

 

[devilfish]

Roakey and Unkle Pug is 100% correct on all counts about spare air. A diver that allows him/herself to use up all the available air is out of control already. To assume that this diver would make a controlled precedure under that situation is fooling themselves. Chances are when the slurp turns to gulp they will be going home to mama at warp seven, never slowing down for any procedures. Next stop is the sausage for few runs on the wrong side of the bib, at best.