13 Cu. Pony Tank

[cebudiver]

Am thinking about purchasing a 13cu. Pony tank. Does anyone have any comments on this size tank as reserve air.

 

[Soggy]

Without getting into the pony vs doubles debate (which will inevitably happen anyhow)...

Do the math for a controlled ascent from 100 ft at a 1.0 cft/min SAC, with safety stop, and I think you'll find it's not enough gas. Look for at least a 20, preferably a 30+, slung like a stage/deco bottle.

 

[dkktsunami]

Am thinking about purchasing a 13cu. Pony tank. Does anyone have any comments on this size tank as reserve air.

I use a 13 cu.ft. pony as a redundant air source for recreational depth diving. Pony attaches to a single 80 cu. ft. al tank with the "quick draw" bracket. This set-up is intended for emergency use only, of course, and is in no way used to extend bottom time. I have never had to use the pony for emergency purposes, but I do practice with it frequently. I often solo dive, and my pony serves as my buddy who is always there, who is never out of air ( I gauge bottle before each dive), who never will need to be rescued, and who is always willing to go diving. You will want to check your SCR to be certain that 13 cu.ft. is enough air to make a slow ascent and perform 3 min. safety stop, keeping in mind that if you are using this thing for real you will probably have an elevated rate of consumption. If you consistently do deep dives or dives that involve more than 3 min. decompression, you probably should look at some other arrangement

 

[cebudiver]

I am just looking into extra safety measures. Am a recreational diver nothing fancy.

 

[ProfessorAronnax]

I saw a sweet 30 cu ft hp tank at DEMA(we immediately it grabbed for our Rapid Diver) by Worthington. It's about the size of a 20 cu ft alum.

 

[markfm]

For me 13 was a bit small, I went 19. I could not have seen going 30.
It absolutely is a "do the math" exercise, but not all that exotic.
A 19 is equivalent to about 750 psi in an AL80. A 13 is equivalent to about 500 psi.
I found it easier to just monitor my gas usage on an 80, from start of ascent at depth until surface.
If my start is at 1000 psi, and I'm on the surface at 500, I used 500 psi, a 13 would be just about the minimum. Bump by a couple of hundred for "what's going on" debug time, and the 19 was my personal answer.
Practicing with it, frequently, making it a normal part of my gear, is for me important.
Good luck!

 

[Tom Winters]

A 13 is more along the lines of a drysuit inflator tank than a bail-out tank. Get a 30 or 40 for a pony bottle.

 

[drbill]

I have used a 13 cu ft pony for the past four years. I feel it is sufficient for the dives I do. I rarely stay below 80 ft for very long and most of my dives are multi-level. If I need the pony early in the dive, I haven't been at depth for very long (assuming it is the first dive). I've done an emergency ascent from 70 ft with 0 air in my primary tank (clogged debris tube) when I forgot my pony.

I dive cool temperate water which increases my SAC rate. If you are diving warm tropical waters, you would probably consume less air.

However, your mileage may vary.

 

[Web Monkey]

Am thinking about purchasing a 13cu. Pony tank. Does anyone have any comments on this size tank as reserve air.

There was a spreadsheet around here that graphed when you would run out of air ascending from various depths with various size tanks.

A 13 comes up a little short, but a 19 worked out nicely from less than 100 feet. A 30 worked well from 130'.

The 19 is only slightly larger outside than the 13.

Terry

 

[doole]

What is the matter with everyone on the board these days? When is somebody going to get in here and say something obnoxious??