Spare Air: some thoughts

[DandyDon]

Uhhh hi Boxturtle. Welcome to Scubaboard.
Yes that would be beating a dead horse.

Not to be confused with simply visiting Dead Horse...
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[RJP]

Can you count how many other reasons there are in the "21 ways you can run out of air" in the list below that have nothing at all to do with poor gas management or buddy skills?

As others have pointed out, proper gas management and buddy skills would obviate the need for a SpareAir in ALL of those cases. Even the ones that are a direct result of failing to maintained/inspect gear.

PS - I especially like the one about your hose being cut on a sharp rock! :shocked2:

 

[RJP]

Cons?

Easy...you're gonna die!

 

[thanksforallthefish]

So does this then imply that divers using pony bottles have poor gas management plans or buddy skills or are irresponsible divers also?????

I have to disagree with this statement. The problem with saying that "its better than nothing" is that the choice to use one clearly indicates a perceived deficiency in alternative strategies for OOA emergencies, because the device itself is inadequate for dealing with those emergencies. Spare air does not substitute for problems in gas management or buddy skills, or simple responsible diving. Of course no one will admit that they're using the spare for those reasons, but in fact that's exactly what they're doing. The spare air is a false solution which by it's nature provides a false sense of security. This is not safe diving. It's far safer to dive fully knowing risks that you might be taking, and modify your behavior accordingly.

Diver behavior and judgment is always the foundation of safety in scuba, whether it's OW or cave diving. Using poorly designed equipment to substitute, even if it's intended as an augmentation, is always a bad idea. People argue that using the Spare Air will not change their dive behavior or judgment, but IMO it already has as soon as you choose to use it, for the reason I just mentioned.

If you are in a situation in which you have a legitimate need or desire for a completely redundant air source, use one that works.

Or, put another way, any diving situation that would be dangerous to do without a fully redundant air source is still dangerous with a spare air.

I can't believe that I can't resist posting about this for the millionth time. I suppose it's because I have a chip on my shoulder about the way the recreational dive gear industry sells equipment using 'safety' as a sales tactic. Usually it's just an issue where someone spends too much money (on a high end reg for example) but in this case I think it's outright dangerous.

 

[RJP]

E: or dive doubles or use an H or Y valve

Why do people insist on lumping H/Y valves in with doubles in discussions of "redundant air supplies"?

Having doubles or a pony bottle provides a redundant gas SUPPLY. Having an H or Y valve offers you redundant ACCESS to the same limited supply of gas. You go OOG, and you can have 20 valves if you want...none of them are going to do you any good.

Folks who understand the purpose of an H or Y valve need to stop lumping them in with "doubles" and "pony bottles" or even Spare Air, lest newbies assume that a different valve will somehow magically provide more gas when needed.

[/soapbox]

 

[BDSC]

So does this then imply that divers using pony bottles have poor gas management plans or buddy skills or are irresponsible divers also?????

Excellent observation.

 

[sdiver68]

ALL of these issues are either completely avoidable or easily dealt with, given a competent buddy and an adequate gas plan.

Exactly. Unfortunately, there is no given.

 

[tomfcrist]

how about that for the price for a spare air you can get a AL 30 or 40 and a (cheap) regulator...

and this is coming from a guy that has repeatedly stated that pony bottles and spare air are useless......what happened to your H or Y valve theory?

 

[halocline]

Yes Matt boy, there ARE oftentimes more than one solution to a problem.

"Aborting a dive and heading for the surface" certainly being one of them. And of course, while heading to the surface, it's rather nice to have..um...a secondary source of breathing gas, dontchya think?

What do you think happens during a free flow? Don't you remember practicing breathing from a free flowing reg in your OW class?

Blown tank o-rings, burst valves, reg failures, all don't result in immediate loss of air. Sure, air escapes from the tank, but if you want to try an experiment, try taking a tank with 500PSI and opening the valve, see how long it takes to empty. The reason I chose 500PSI is because it's a commonly used reserve figure for OW. By comparison, a 3cft spare air (the larger one!) is equal to about 120 PSI in an AL80, if it holds a true 3 ft, which I don't know. And of course you realize that anything that can happen to a tank or reg can also happen to a spare air. You mentioned freezing; well, I've got a bit of news for you, the spare air heat exchange looks pretty bad to me, and if a full size reg with a few feet of hose to warm up the air between 1st and 2nd stage freezes, take a guess what's very likely to happen with this device in cold water.

BTW, I went to the spare air website to see what the actual sizes were, and what did I see but "21 ways you can run out if air". I guess that's where you got that mis-informed list. Well, here's number 22: using a pathetically small bail-out bottle to deal with an emergency that should never have happened in the first place

 

[halocline]

So does this then imply that divers using pony bottles have poor gas management plans or buddy skills or are irresponsible divers also?????

No, and that's exactly why I said in the same post "If you are in a situation in which you have a legitimate need or desire for a completely redundant air source, use one that works."

You did see that, right?

A 13cft pony is equal to roughly 500PSI in an AL80, which is an accepted reserve for most OW no deco diving. I'm not sure I'd want to surface from 120ft on one, but there is also 19cft, which is roughly equal to 750 PSI in an AL80. These are legitimate, useful air sources that can actually provide some redundancy, IMO.