Recommendation for recreational pony bottle size

[vilinsky]

I'm looking to purchase a back up spare breathing pony bottle system for recreational diving here in So. Cal. People have recommended the Spare Air others says go to a 6cf rig and yet others say go for a 13cf. I'm not a tech diver and the deepest I have ever gone is 100, but I usually stay between 40 to max 80 feet max. Any suggestions??? Thanks, Vlad

 

[JohnN]

I'm looking to purchase a back up spare breathing pony bottle system for recreational diving here in So. Cal. People have recommended the Spare Air others says go to a 6cf rig and yet others say go for a 13cf. I'm not a tech diver and the deepest I have ever gone is 100, but I usually stay between 40 to max 80 feet max. Any suggestions??? Thanks, Vlad

I went with 19cf.

Figure your SAC at 1.0 (poo has hit the fan) and it will take you a minute at depth to settle down. At 100' that's 4 cf of gas. If you were to blow off your safety stop and to straight to the surface, figure 30 ft/min of ascent that's 100/30 = 3.3 minutes to get to the surface. 50 foot average depth so 50'/33 = 2.5 atm. 2.5* 3.3 minutes = 8.25 cf of gas. So now you're at the bottom of that 13 cu ft bottle (you'd have roughly 170 psi left).

Not a pretty picture at all if you have a 6 cf bottle and the 13 cf bottle doesn't give you any wiggle room.

YMMV of course

 

[Stoo]

Most of the cost of a pony is in the reg and valve.. tank size doesn't change the cost a lot. Similarly, the weight difference, isn't significantly different between a 13, 19, or even 30 or 40.

You might consider going to one of the larger sizes and "sling it" with a stage kit, rather than mounting it on your primary tank. (So you don't need to schlep it into the shop when you get your main tank filled.)You have access to the valve, and can carry it separately from your single. It works well, and the tank just kinda floats up under your arm.

And there's no such thing as too much air. In a high stress situation, at a deeper depth, you'd be amazed at how fast you will suck one of those little ponies down. Not withstanding JohnN's calculations, do you really want to blow off a safety stop...??? Consider that if you run out of air at depth, or suffer an equipment failure, OR your buddy does... and I will guarantee you that you'll be exceeding any acceptable ascent rate.

For another $50 or so, you can get up, AND not get bent. I call that "win-win"...

 

[Jim Lapenta]

I have two 30's and a 40. Also own a 19 but it's only for the pool or my gf. For her a 19 is as good as a 30.

Sent from my DROID X2 using Tapatalk 2

 

[Glenn08]

I changed from a 72 and about 12 pony to twin 50's with a manifold: two valves and two complete regulators. I would rather have a little extra air than not enough. This was originally for redundancy for under-ice diving, but now it is my favorite rig.

 

[Stoo]

I changed from a 72 and about 12 pony to twin 50's with a manifold: two valves and two complete regulators. I would rather have a little extra air than not enough. This was originally for redundancy for under-ice diving, but now it is my favorite rig.

I did much the same thing a long time ago... In my case, mostly because I dive solo a lot. The only single's I own now are stages. (But a pony is better than nothing... I just suggest a Clydesdale, rather than a Shetland!)

 

[Chugwhump]

I use a 19cf with a Quick Draw Easy Mount.
I am in SoFla.
I use it in the 50' to 115' range.
After 115' it's time to stay very close to my dive buddy.
My diving is usually:
Warm water year round.
Wetsuits.

Chug
Best dive buddy I ever had is made of aluminum.

 

[halocline]

Probably the most useful overall size for what you're describing is a 19 cft. Anything smaller than a 13 is probably not worth carrying, and anything larger than a 19 is getting to be a stage bottle. But it might be worth it to really examine why you feel the need to carry redundant air. I bought a 13 cft pony years ago and have used it diving exactly once. It is handy for checking regulators and putting air in tires.

 

[Kharon]

The standard valve and 1st stage are way too bulky and make the pony clumsy. I put together a very streamlined unit for about $185 to $225 with all new components. Check out Goodrum International for these:

H2Odyssey valve/1st stage ($71.76):
Piston First Stage - RG2V - Marine Scuba Gear Air Systems - Goodrum International

fill adapters:
station ($34.50) Station Filler - EAS1-4 - Marine Scuba Gear Air Systems - Goodrum International

yoke ($40.25) Yoke Filler - EAS1-3 - Marine Scuba Gear Air Systems - Goodrum International

spg ($13.80):
Deluxe Pony Gauge - GPD - Marine Scuba Gear Guages - Goodrum International

I got both fill adapters but I almost never use the tank-to-tank yoke filler.

I got a 13cf Catalina from LeisurePro ($100 and sold the valve for $35 = $65 net):
Catalina Pony Bottle Tanks, Yellow with Pro Valve | LeisurePro

Note: if you want a 19cf pony it's only $20 more – a 6cf is $7 less. I like the 13cf - double the air for $7, it’s not all that much bigger, and I can reach the surface with a safety stop from 130 feet.

I made my own sling (http://dir-diver.com/en/equipment/stagebottle_rigging.html) with some minor modifications and used the octo from my main reg (now unnecessary and a snag point).

Note: I think it's insane to have two 2nd stages off a pony or off the main if you are carrying the pony. Too many hoses to confuse, tangle, and possibly fail. I moved the octo from my main to my pony as SDI Solo Diving Course recommends.


Total: $185.06 without the yoke fill adapter and $225.31 with it.

 

[Instructor_Tom]

I'm looking to purchase a back up spare breathing pony bottle system for recreational diving here in So. Cal. People have recommended the Spare Air others says go to a 6cf rig and yet others say go for a 13cf. I'm not a tech diver and the deepest I have ever gone is 100, but I usually stay between 40 to max 80 feet max. Any suggestions??? Thanks, Vlad

I know this doesn't answer your question, but don't get a pony. Use proper gas management and proper buddy skills and you will never need a pony.

To me anyone who dives with a "Spare Air" tanks, is someone i don't want to dive with.

The only time i dive with a reserve tank and it is not explicitly needed for the dive is when i am diving with a student in a cavern area where i have not been able to determine their consumption rate prior to the dive and then it is an AL40 as a side-mount.

Know your sac rate, plan your dive, and then dive your plan.

T.


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