Spare Air questions

[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.