Recreation diver:pony bottle?

[Simon Chang]

Hi,guys!
I'm wondering about the issue...
Some senior divers told me not to use the pony bottle!It's stupid!
Really?
Only a few divers use pony bottles in Taiwan...Especially when shore diving...
Why?
Please suggest me how to choose a right one for 40m ascend + 5m safety stop!
Most dives,I dive depth less than 28m.
S13 pony bottle will meet the requirement?
Does the common double tanks strap fit for the main cylinder with pony bottle?

Simon Chang

 

[lamont]

most recent thread on pony bottles:

http://www.scubaboard.com/showthread.php?t=156904

 

[fire_diver]

Anyone telling you that using a pony bottle is stupid, is either stupid themselves, or hopelessly lost in the past. That link to the previous pony discussion has some great info. If you still have questions, do search here for "pony", you'll find enough to keep you busy for day just reading.

FD

 

[jpcpat]

A pony bottle is one of those things you never need, unless you need it bad. How big a bottle you need depends on a lot of factors. For an ascent from 130 ft with a safety stop, I carry a 6 cu ft. Many people chose a larger bottle. YMMV

 

[OBXDIVEGUY]

I carry a larger bottle that can also be used as a stage bottle sometimes. It is an aluminum 40. Never needed it, but glad to have it.

 

[shellbackdiver1]

Mr. Simon Chang,

Pony bottle should be your dive buddy and good gas planing. If you are looking to dive on the weekends in Kenting let me know for I go every weekend and usually once during the week day.

By the way I assisted you in your pool skills during your open water....remember?

Greg

 

[Sideband]

Mr. Simon Chang,

Pony bottle should be your dive buddy and good gas planing. Greg

I've never had a bad pony bottle but I have had many bad buddies.

Joe

 

[markfm]

As to "how large", it depends on your gas consumption.
A full 19CF tank is just about equal to 750 psi worth of gas in an AL80 tank. For me, that works, I can get up from my max depth cleanly, with a little margin.

A 6CF is about equal to 230 psi worth of gas in an AL80 -- no way I can make it from deep, with any kind of safety stop, on 230. Someone with a superb SAC might do it, just not me, especially with a bit of "uh oh" time at depth, as I switch over to the pony, figure out what's wrong and that it's indeed a bailout scenario.

Check how many psi you go through on an ascent from max depth, under a non-stress condition (working with your regular, functional, tank -- just write down the PSI at start of ascent and at the surface). Actually, try writing down your PSI about minute before you start the ascent, simulating a little whoops time. For any given tank, that PSI used can be converted to how many cubic feet of gas you used.

(It just happens that an AL80 is really about 77 ft3 of gas, at 3000 psi nominal pressure. A 19CF pony is a true 19, and 19 is real close to 1/4 of 77, so a full 19 is equal to a 1/4 tank on an AL80. 1/4 x 3000 = 750 psi --> a full 19 pony is equivalent to 750 psi in the AL80.)

A 19 can indeed cleanly be mounted on your BCD, multiple ways. I use a tank-mount option called a QuickDraw, a little piece that fits on the main BCD tank strap and another piece that goes on the pony bottle. There are other similar products to make mounting the pony on your back, along with the main tank, painless. There are also many people who prefer to sling the pony on the front, tying it off to D-rings on the BCD. Both approaches work, and work well.

(Maybe, just for once, avoid the back mount vs. slung wars? )

 

[shellbackdiver1]

So far so good.... Still alive so I guess I pick em well, plan the dive and dive the plan.

 

[mello-yellow]

I usually wear a 13 cf pony when diving deeper than 60’; always when deeper than 80’. When diving alone, I always wear it and do not exceed 45’ depth.