Pony bottle question

[DJ457]

So, I would like to get myself a pony bottle. Would be used as a redundant air supply when doing solo diving as well as dives deeper than 100'.

My question is - would you get a Steel pony or Aluminum pony?
And then also what size. I was thinking a 30 or 40cf?

Thanks for the help.

 

[Yoyodyne-88]

I dove with a pony for years, for similar reasons, and an AL80. I chose a 13cf bottle, enough for a safe ascent basically.

Seems to me by the time you drag a 40cf around, you may as well go to doubles. Which I have now.

 

[Basking Ridge Diver]

Do you know your RMV or how to figure it out? That is your starting point.

 

[Locus]

I found this very helpful when making the same decision: https://decodoppler.wordpress.com/2...y-the-maligned-and-misunderstood-pony-bottle/

Bottom line: a by-the-book emergency ascent from the recreational dive limit (40m) requires approximately 25cu ft of gas or more for someone with average SAC.

For me, this makes an AL40 the prudent choice for a pony, since it can provide ample gas for an emergency ascent from the deepest depth I am likely to go in the foreseeable future. It is also the most cost effective means for me to add gas redundancy at the moment, and if/when I progress to doubles it can still have a second life as a stage/deco bottle.

 

[wolflegresley]

I use an al40 for just this reasson. I recommend googling Steve Lewis and buying his books - lots of other good information - but he has a wonderful discussion on pony bottles (also on his blog as well).
whats also great about a 40 is that It can grow with you into tech diving!

for me it was the perfect choice - not much extra drag and there's nothing like having your bailout gas right next to you when your diving deep...really helps in keeping calm. But do yourself a favour and make sure the reg you buy for it is as good as your primary - if not better.

 

[dumpsterDiver]

So, I would like to get myself a pony bottle. Would be used as a redundant air supply when doing solo diving as well as dives deeper than 100'.

My question is - would you get a Steel pony or Aluminum pony?
And then also what size. I was thinking a 30 or 40cf?

Thanks for the help.

An aluminum tank is going to be close to weightless in the water, a steel is going to be heavy. Generally you will wear it on your chest D-ring or straped to the side of your main tank. In either case you will be wearing it on your side, where having a negative tank is going to affect your balance in the water.

I use a 13 cu-ft tank to 130 ft... I think a 19 would be OK for most people to the recreational limits if you are not in deco and you can ascend immediately. We have had endless arguments over pony size. You need to determine how fast your use air, if you want any buffer to handle problems on the bottom and if you want to have air for a safety stop. Do the math, and pick what you are comfortable with. Tonight I was packing for a 90 ft dive tomorrow. I have a choice of 13 or 6 cu-ft tanks and I grabbed the small one because it is so small and I will not be in deco.

 

[uncfnp]

http://www.scubaboard.com/forums/ta...pony-what-size-how-mount-other-questions.html
http://www.scubaboard.com/forums/tanks-valves-and-bands/130446-pony-bottle-size.html
http://www.scubaboard.com/forums/ta...mmendation-recreational-pony-bottle-size.html

Just the first few I found. Probably one of the most frequently asked, and hotly debated, questions on SB.

 

[JohnN]

For me, this makes an AL40 the prudent choice for a pony, since it can provide ample gas for an emergency ascent from the deepest depth I am likely to go in the foreseeable future.

I'd love to know how you get that AL40 onto an airplane when you travel. . .

 

[grf88]

I'd love to know how you get that AL40 onto an airplane when you travel. . .

The OP did not mention anything about airline travel. If you want to travel with a pony you may have to settle for something that is not optimum.

 

[JohnN]

The OP did not mention anything about airline travel. If you want to travel with a pony you may have to settle for something that is not optimum.

My point exactly, although I find an AL19 works for all recreational depths I encounter with a sufficient safety margin (and I do the math at a SAC of 1.0 cuft/min). As noted earlier, unless you're doing deco (and you better have a solid plan for lost gas), an AL19 should be sufficient.