Hi guys, just wanted to ask which Bail Out Pony tank to get for recreational diving, a 6, 13 or 19cft? Any input would be greatly appreciated. Thank you.
Vlad
Vlad
Bail out Pony Tank 13 cft or 19cft?
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There's at least two active threads on this subject, and some diverging thoughts.
Most people would say "The more gas, the better."
However, I bought a 13 when i bought my pony. I went with a 13 because it's small enough to fit into my luggage when I travel via airplane to other countries. The bigger the pony, the harder this will be to manage.
So, are you planning to pack it in your luggage for an airplane ride? If so, think small. If not, get the bigger one.. you might even go with a 20 or 40. Personally, i'm doing a solo dive where the 13 might be a concern then I will just go with regular (sidemount) doubles.
I don't think I'd consider carrying anything smaller than a 13. The 13 is already fairly small.
Most people would say "The more gas, the better."
However, I bought a 13 when i bought my pony. I went with a 13 because it's small enough to fit into my luggage when I travel via airplane to other countries. The bigger the pony, the harder this will be to manage.
So, are you planning to pack it in your luggage for an airplane ride? If so, think small. If not, get the bigger one.. you might even go with a 20 or 40. Personally, i'm doing a solo dive where the 13 might be a concern then I will just go with regular (sidemount) doubles.
I don't think I'd consider carrying anything smaller than a 13. The 13 is already fairly small.
Soloist
Contributor
Do you plan on flying to your destination or driving? I have a 13 for airline travel and a 19 for everything else. Hope this helps.
runsongas
Contributor
Not much difference to either if you are going straight to the surface. Al19 gives a cushion, but the 13 is fine if you get it cheap.
Kevrumbo
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Let's just do an easy quick estimate from the recreational depth limit of 130fsw to the surface.
Tally the depth ATA's:
4.9
4.6
4.3
4.0
3.7
3.4
3.1
2.8
2.5
2.2
1.9
1.6
1.3
1.0
----
Total: 41.3 , lets round this up to 42 ATA
Multiply 42 ATA by 1 cf/min*ATA stressed breathing rate, and multiply again by 1 minute stop at every 10 feet equals 42 cf (42 cubic feet) consumed at a slow conservative ascent rate to the surface of 10fpm (10 feet-per-minute); for a nominal ascent rate of 30fpm to the surface, estimate 14 cf consumed; and for an emergency max ascent rate of 60fpm to the surface, estimate 7 cf consumed.
So depending how deep you want to go (i.g. in this example maximum 130fsw recreational depth limit), and what kind of ascent profile to perform (continuous 10fpm, 30fpm, or emergency max 60fpm ascent rate to the surface from 130fsw, or perhaps to a 3 minute safety stop at 20fsw?), you have the option of choosing a 13 cf, 19 cf pony bottle -or more conservatively- a stage tank slung 30 cf or 40 cf larger cylinder bail-out.
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I don't think recreational divers usually stop during ascent except to do an optional safety stop at 15' (or 20 depending on who taught you) or a deco stop if they screwed the pooch. If I was on my pony due to OOA on main during a recreational no-stop dive then I would definitely skip any optional safety stop. I mean if I was on my al13 and I still had 2000psi in it when I hit 15' I MIGHT think about doing a safety stop. Maybe. Just my opinion. I've never run OOA though, so it's just a guess as to how I might actually react. Most rec divers don't plan for multiple failures (OOA and mandatory deco stop for example).
The 40 can grow with you
We went through this in a recent thread, but here are my thoughts for the new OP. I'm not referring to situations where you need to fly somewhere with your pony tank. I understand that this would involve a compromise that is outside the realm of dive planning.
1) If there is value in doing a safety stop, you should do it on every dive.
2) If there is no value in doing a safety stop, they don't bother doing it on any dive.
3) If the emergency is that for some reason you are out of gas, and you have a redundant gas supply, once you have switched to it you are now no longer in an emergency situation, and you have plenty of gas to do whatever ascent protocol you have previously determined to be safe and optimal.
4) if you DON'T have plenty of gas, you should ask yourself why that is, and what can you do about it. If an AL19 or an AL13 gives you plenty of gas to do your normal safe ascent in case you lose your primary gas source (accounting for short fills, minor gas loss during the dive, etc..), then that would be a fine choice. It isn't for me, but then again, my SAC rate isn't so good...
5) If you choose not to do a SS because you aren't bringing enough gas, I don't think that's good planning.
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Make your own conservative cylinder volume calculation. A minute at depth, normal ascent to the safety stop, normal safety stop, normal ascent to the surface. I use twice my normal average RMV, use what you think is appropriate. I think this is pretty conservative. You may not need the minute at depth. Obviously, on a no stop dive, you could skip the SS if needed.
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