Spare Air questions

[Weston]

Has anyone used these in real life, thoughts concerns or ideas on them. I'm considering due to often solo diving requirments.

[Chris H]

Get a 40cu ft pony and sling it like a stage. I've used it in real life and it works really well.

[divegeek]

Even a 30 cu ft will work out great. I've seen the Spare-air holster things on some trips. Some people had them attached to their Bcs in the holster, and I even saw one that had a pocket built right into the Bc for the Spare Air. All they do is get in the way and the little tanks themselves never seem to stay in the holster. Plus, the coiled lanyard is really a pain to keep from getting tangled in other gear. You're better off both safety-wise and $$$ wise to buy a pony and a separate reg.

[Vtach]

Spare Air system is generally useless for most diving applications. Your best bet is to add some sort of redundancy to your air supply through either an extra tank (pony, stage bottle or doubles) and an extra first and second stage regulator. The next best option is to use a dual outlet valve on a single cylinder with 2 first and 2 second stages.

I prefer using double tanks with a dual outlet isolating manifold and stage bottles when necessary. They are definitely more costly but the redundancy is hard to beat.

[dfreeman]

I agree with Todd. My preference is a PST E8-130 tank which provides a lot of air, H-valve and dual 1st and 2nd stage regulators. Air quantity is equivalent to a aluminum 80 and a 40 cuft stage bottle.

The next step past that is dual tanks, just as Todd indicates. But pretty expensive and heavy.

Doug

[Cavern Junkie]

I also suggest using a pony instead. I use a Al 30

[Rik]

Asking the experts!
I've seen the statement on some of the spare air bottles stated "50 breaths at the surface"
Allright thats great at the surface but if I was at the surface I would'nt need the Dang thing!
Real question now, what size pony bottle do I need for rec depth s of say 100 ft and with a saftey stop at 1/2 my depth?
Thanks for your input.

Rik O+<

[john j]

Had a friend who owned a WI dive shop about 10 years ago. He told me numerous times that the Spare Air was junk. Said that the regulator on the thing was crap. Cylinder is too small too. Maybe they have been redesigned since then and if so, my point here may be invalid. Even so, the cylinder is too small.

I agree with those below that say get a small pony bottle. Even a 30 cubic foot would be a nice volume of gas. Mount it on your side so you can easily and quickly add it or remove it as you wish. If you don't want it, leave it on shore. If you do want it, just clip it on and go. Quick, easy and simple. One you practice with it a few times, you'll hardly even know it is there. You also need to be able to easily reach the tank valve in case the reg starts freeflowing. If you mount it on your back it is harder or even impossible to do this. There are some really goofy pony mount systems out there. Forget those-Just clip it on your side. Another cool thing about about a side mount pony is that you can remove it and pass it to a diver who is out of air or trapped, whatever. It just gives you lots of options that the spare air will never compete with.

Having a second regulator is never a waste of money. It's great for a redundant air supply, or if your main reg starts having problems, you have a second reg available which may allow you to salvage the dive trip. I suggest getting another reg just like your main one (same brand and model), assuming your main one is a good reg. That way, you have spare parts compatibility.

As far as how much air do you need to get up from 100 feet? Next time you are on a dive that deep, record your tank pressure right before the ascent and then do your ascent with the safety stop. When you reach the surface, record the final pressure. Calculate the PSI you used and then figure how many cubic feet you used. If you need help with the calculation, there are lots of people on this news group that can help-just ask. Once you know the number, then tack on a safety factor that you feel comfortable with. Remember, in a true emergency, you'll likely be breathing more rapidly. Many tech divers figure on having 33% (or 1/3) extra gas as a safety factor.

[Omicron]

If you are doing solo diving, definitely scratch the spare air.

A spare air is good for one thing only - ensuring that you can survive a CESA. A CESA could be (I'm imagining here, never having had to do one due to good planning) a rather stressful experience on one breath...or, maybe no breath if you go to take a deep breath and find nothing in your tank.

A spare air will give you a couple of breaths - enough to get you to the surface from recreational depths doing a 60ft/min ascent.

That's about all they will really do for you though.

Start looking at the cost!! A 3cf Spare Air runs around $200. You can get a small pony and halfway-decent reg for not too much more than that. And then you are talking about 30-40cf of air - enough to let you get to the shallows, do a safety stop, and get out nice and slow.

My preference is to use a big tank as well - I use E8 130's, with H-Valves and two regulators. If one fails, I can shut it off and go to my backup.

It's up to you - if all you are looking for is a few breaths while you are doing a CESA, go for the Spare Air. Otherwise, go for a pony system!!!

If you are interested to see how they hook up to your current rig, here is one example of a good system:

[Chris H]

I'm going to disagree on this being a good system. I'll also admit that I used one exactly like it for years (I'll sell it to you cheap if we can't convince you to do this a better way ). It is nearly impossble to reach the valve. Clipping the bottle to your left side like I mentioned earlier is far better. John J explained some of the reasons for this in his post below with the most important reason being that I can unclip the stage and give it to anyone who is having a problem and then we aren't limited by hose length or any of that sort of thing.

In any situation, especially solo diving, you MUST be able to reach your valves. I dove a single with an H valve on it last night and it was MUCH more difficult to do valve drills with the H valve than with doubles. It is very dependent on tank position, so I need to be very careful when I attach the tank that I get the height exactly correct so I can reach the valves.