An actual legitimate use for spare air???

[Zef]

Spare Air is great to have for the surface interval....use it to get the charcoals in the bbq grill going quicker....just hit the purge button and direct the air to the lit charcoal.

-Z

 

[BoltSnap]

When I carry or feel that I need to carry an alternate air supply for emergencies, I have to think of what possible scenario where I'd need this set up, I monitor my air supply religiously and have definitive dive plans with definitive pressure milestones I stick with in my diving. My concern isn't about me running out of air just because I was careless about monitoring air pressure but I am more concerned about catastrophic loss of main air supply due to some totally unforeseen failure or, most likely, I was entangled in some sort of a net or fishing line or natural structure that kept me underwater beyond my pressure limits and couldn't free myself in time to return to the surface using my main air supply. In this scenario, having a spare air is totally inadequate to the point of being an incentive to commit suicide by thinking that it will get me out of trouble in an entanglement. Spare Air isn't going to give me any air/time to free myself from the entanglement and get me back to the surface. It will in fact make me falsely think that I have a back up for these serious scenarios when I don't and it won't help at all. An appropriately sized pony bottle with regulator will help me and get me out of these "tight" spaces indeed. Same line of thinking applies to a buddy who is OOA and I have to give him a enough air for him and I to come up to the surface.

 

[Perryed]

The argument that a small spare are could be used to make a more controlled CESA makes sense. Instead of bolting from depth, it is easier to come up slow, taking a breathe and continuing to exhale as long as you can before another breath. However, if you took the time to think of that plan and acquire the gear necessary for it, then why would you not just get a proper pony bottle? If its life safety then dont short change yourself just to save 8 lbs...

By that thinking, just don`t run out of air. Problem solved.

 

[scubadada]

I dive with a proper sized pony. I could make a direct ascent to the surface from 130 feet at 60 ft/min with the 3 cu ft Spare Air. Some air is better than no air, not that I would recommend it.

 

[gypsyjim]

I carry a cup of gas in my van, just in case I run out on the highway.

What a waste. Just carry some rubber tubing, and steal what you need from another vehicle?

 

[spitfiremac]

[Edit, I changed 'deco stop' to 'safety stop' after the below comment. Terminology is important here and these shouldn't be confused.]

Thanks all.

I agree it's not a solution beyond just being a bad one.

The sole point -valid or not- is that it will provide enough air for one person at a 5m safety stop for about 3-4.5 minutes depending on breathing. I've heard people say it wouldn't even do that, though they clearly didn't do the math.

The failure chain to get someone there is so dramatic as to be laughable if it wasn't so serious, and in such cases something would have gone so catastrophic that a second tank or pony is much more likely to be the solution.

Looks like we've come to a consensus. Safety stop doable, but not needed, and not the better option if it is needed.

Thanks again.

 

[OTF]

it could be a useful escape aid on a sinking or burning boat

I agree that it's a false sense of security, but also that a CESA with 3-6cf of extra gas to breath is better than a CESA with zero.

 

[BlueTrin]

Thanks all.

I get it, I agree it's not a solution beyond just being a bad one.

The sole point -valid or not- is that it will provide enough air for one person at a 5m deco stop for about 3-4.5 minutes depending on breathing. I've heard people say it wouldn't even do that, though they clearly didn't do the math.

The failure chain to get someone there is so dramatic as to be laughable if it wasn't so serious, and in such cases something would have gone so catastrophic that a second tank or pony is much more likely to be the solution.

Looks like we've come to a consensus. Deco stop doable, but not needed, and not the better option if it is needed.

Thanks all!

Usually people use ‘deco stop’ for a mandatory stop. A spare air would never be useful for a dive with mandatory stops, it is way too small for a deco dive.

Then people use ‘safety stop’ for a non-mandatory stop. You should not do a ‘safety stop’ in case of emergency, it is only done as a safety: if you are in danger it will not add to your safety to do one.

If you do not have any ‘deco stops’ and you ran out of air, you should NEVER do a safety stop with a spare air: you are putting yourself at danger of dying: because you do not have any mandatory stops, you should go to the surface and inflate your BCD manually if you really OOA. Using your spare air for a safety stop would be the best way for you to run out of air twice in the same dive. For example, the spare air will not inflate your BCD.

 

[Boston Breakwater]

Hello.
Do I want a Spare Air
Cheers.

 

[johndiver999]

Usually people use ‘deco stop’ for a mandatory stop. A spare air would never be useful for a dive with mandatory stops.

Then people use ‘safety stop’ for a non-mandatory stop. You should not do a ‘safety stop’ in case of emergency, it is only done as a safety: if you are in danger it will not add to your safety to do one.

If you do not have any ‘deco stops’ and you ran out of air, you should NEVER do a safety stop with a spare air: you are putting yourself at danger of dying. This would be the best way for you to run out of air twice in the same dive. For example, the spare air will not inflate your BCD.

You really think chilling at 15 ft on a spare air is putting yourself in danger of dying? Why?

Are you worried it will run out and you can't make it from 15 feet to the surface after resting comfortably for a few minutes as you wait for the signal that the tank is MT?