Spare air - or not?

[Teamcasa]

Spare Air is like a lot of the gear a new diver buys. Many new divers buy one, use it until they see a better solution and off to eBay it goes.
Lynne is exactly on point, when she says

The BEST solution to being out of gas is not to do it, which means gas planning and maintaining adequate reserves.

That being said, if I needed air (for whatever reason) and the only option available was that little yellow can-o-gas, you can bet your butt I'd use it.

 

[*dave*]

No, I think you are missing Don's point... holding the weight in your hand ensures two things -

1) that you won't have an uncontrolled ascent (admittedly not much of an issue once you are doing a CESA)

How does holding weight in your hand on ascent control your ascent?
For cold water divers, holding a tenish pound pouch would effectively tie the right hand, making it useless for mask clearing, reg retrieval or any other function.
Ascent rate is nearly everything during an OOA ascent, so your statement that it is "not much of an issue" is confusing. The likelihood of dropping a weight pouch while you are holding it is a helluva lot higher than if it's stowed where it belongs. If the OOA diver drops the pouch, then what?

2) that if you pass out (but don't die), you will drop the weight on the surface, so that you can be rescued!

So, you pass out at 30' and you somehow hold onto the weight till you get to the surface? How does that work?

And a coroner probably has some good insights into what kills people, he might be just the guy to keep you alive!

Adding a procedure because other fundamental procedures have broken down is how governments are run. Shoring up the fundamental skills would eliminate the issues these half assed procedures are intended to bail people out of.

Can you cite one documented case where such an ascent saved a life?

How does this work for divers using weight belts?

Is there an agency that teaches this method of ascent?

Or maybe I missed the joke?

There was a joke?

 

[doctormike]

That being said, if I needed air (for whatever reason) and the only option available was that little yellow can-o-gas, you can bet your butt I'd use it.

This is the least controversial statement that I have ever read on Scubaboard. I agree 100%!


A guy starts choking in a restaurant, and a doctor comes up behind him and gives him the Heimlich maneuver, saving his life. The guy is so grateful that he asks the doctor how much he owes him. The doctor says to forget it, but the guy insists on paying, and wants to know what the fee is for that service. The doctor says "OK, give me half of what you would have given me when you were choking".

 

[doctormike]

How does holding weight in your hand on ascent control your ascent?

The same way it controls your ascent on your belt or strapped to your tank or in a pouch. It's negative buoyancy. By switching the weight to your hand, if you pass out, it drops. On your belt, it stays.

Don was just referring to a trick to automatically give you some positive buoyancy in case you lose consciousness. I had never heard of it before, but it does make sense.

For cold water divers, holding a tenish pound pouch would effectively tie the right hand, making it useless for mask clearing, reg retrieval or any other function.
Ascent rate is nearly everything during an OOA ascent, so your statement that it is "not much of an issue" is confusing.

Meant to say not as much of an issue, sorry typo. But I do stand by the statement that if you are completely OOG and doing a CESA, you will ascend faster than normally. Yes, from a DCI point of view, you are putting yourself at risk, but if you are truly OOG, you won't be doing the normal safe slow ascent. So it would be less of an issue to be underweighted.

HOWEVER, the point is that Don was saying that you can hold the weight (as opposed to ditching it at depth) so that you will get the protection from runaway ascent, while having the advantage outlined above. Sure, it's a tradeoff, we don't normally dive with weights in our hands. But if you are OOG and doing a CESA, why would reg retrieval even be a concern? Or mask clearing, for that matter?

So, you pass out at 30' and you somehow hold onto the weight till you get to the surface? How does that work?

I think that you may be overthinking this. If you pass out at thirty, you are more likely to drop the weight, and thus more likely to float to the surface, and thus less likely to drown. Not sure why this is controversial... I agree, certainly not a standard technique that is taught in OW class, but it's a good tip for a true OOG emergency. I probably wouldn't remember to do it, but the physics make sense to me..!

Can you cite one documented case where such an ascent saved a life?

No. But then again, I can't cite documented cases of anything. I still think that it's OK to post!

How does this work for divers using weight belts?

I would imagine the same way. You unbuckle the belt, hold it in your hand, and head for the surface.

Is there an agency that teaches this method of ascent?

Not that I have ever heard of, unless you count ScubaBoard...!

 

[doctormike]

But if you are OOG and doing a CESA, why would reg retrieval even be a concern?

And yes, I know that sometimes you can get another breath out of an "empty" tank as you ascend. So if you forget to keep your reg in your mouth AND have a weight in one hand, then you would only have one hand left to put the reg back in.

In my case that would be a problem, because I am NOT letting go of my camera, even with the tether...

 

[MaxBottomtime]

If you have time to take out a weight and hold it, it probably wasn't much of an emergency. If there was no other option I would be on my way up.

 

[tadawson]

Omitted quote . .

 

[tadawson]

Considering .6atm, I highlighted in red, is about 4100' altitude, I would suggest checking your math as well as the person you are correcting.


Bob
----------------------------------------------
I may be old, but I’m not dead yet.

I already did - several times. Comparison of an 80cf to a 3cf is a simple linear scaling - really hard to get wrong, and if anything, the higher altitude gives you more, not less, in terms of breaths.

And note that I said "atmosphere" and *NOT* ATA! 33 feet seawater is 1 atmosphere of pressure, so 20 feet is about .6 atmospheres, or 1.6ATA, which is what I calculated . . .

- Tim

 

[doctormike]

I already did - several times. Comparison of an 80cf to a 3cf is a simple linear scaling - really hard to get wrong, and if anything, the higher altitude gives you more, not less, in terms of breaths.

And note that I said "atmosphere" and *NOT* ATA! 33 feet seawater is 1 atmosphere of pressure, so 20 feet is about .6 atmospheres, or 1.6ATA, which is what I calculated . . .

- Tim

Never heard that usage before...

Ambient pressure at 33 FSW is 2 atmospheres of pressure, or to use the more correct term, 2 ATA. ATA stands for "Atmospheres Absolute", that is, the total pressure exerted by the column of gas (the atmosphere) and liquid between you and outer space. So it's 1 atmosphere for the atmosphere, and 1 atmosphere for the water.

At 20 feet, ambient pressure is 1.6 atmospheres (aka 1.6 ATA, aka 1.6 bar)

But I think that we know what you meant... Did you mean .6 additional atmospheres?

M

 

[bpotkin]

As the new diver who purchased the yellow bottle, I tested it at aprox. 25 ft. and got bored after a dozen or so breaths. Can't say it breathes as nice as my B2.