Pony tank

[Divin'Papaw]

Ok I see where your confusion is coming from @JimBlay

In your haste to discredit my advice you clearly missed my post where I clearly explained that I treat the pony bottle as a redundant air source throughout MOST of the dive, but toward the end of the dive I consider it to be my reserve.

Thanks for giving me the opportunity to clear up the misconception.

Sorry. Your attempt at humor aside it’s horrible advice and violates all standard practice for solo diving or other uses for a redundant air source. It’s your planned reserve period.

 

[Ghost95]

Oh, wait. Are we doing humor?

If we are, then the OP should get some split fins, a dry snorkel, and a Spare Air and he'll be good to go!!!

As long as he has a Perdix...

No, seriously, just get bigger tanks...

 

[lexvil]

So what does a side mount diver call the “other tank”?

 

[Ghost95]

So what does a side mount diver call the “other tank”?

"Lefty"

 

[lexvil]

"Lefty"

And those using the left one first?

 

[Ghost95]

And those using the left one first?

"Steve"


or "Poncho"

 

[broncobowsher]

Ok. So, if I understood the "problem" correctly, it is based on naming his second tank a "pony".
If he names his second tank as just his second tank, then there is no problem?

Yes still a problem. Take a sidemount class and learn what proper gas planning using multiple tanks and gas switches during a dive is. So one tank is bigger and back mounted, still proper gas management.

You never see a sidemount diver come back and claim they sucked one tank down to 50 PSI but that is OK, the other one is still full. What they do is take some from one tank, then some from the other, back to the first, etc. Come back with roughly balanced pressure between both tanks.

In this case (guessing everything here is air) there should be some gas switches during the dive. It will be a bit ugly with mis-matched tank sizes. But that would be the more proper way to run a staged bottle setup.

That way you will always surface with air, even if one reg craps out and you are running a little late that day. Downfall, you are paying for 2 fills instead of 1. A more correct solution would be to run a larger primary tank and keep the pony. Or get a pair of tanks and run them down sidemount style.

Just because the gauge says you have pressure in your stage/pony/monkey butt cylinder doesn't mean it will be usable at the end of the dive.

I know several boats that if they saw you come up with that little air, you would not be allowed in for a second dive. If allowed on the boat ever again.

 

[Ghost95]

A stage, which is what you have when you plan to use your 19cf bottle for your accent because your main tank is empty, is different than a "pony" that you would only use in an emergency.

Stages are different practically, theoretically, and physically from a pony bottle, which is nothing more than an emergency accent bottle, providing a gas supply just to get you to the surface.

 

[Coztick]

Using the extra cylinder as part of your gas planning means your using a stage cylinder not a pony. A pony is for when things go pear shaped.

Agreed.
But what is your reserve for then?

 

[Ghost95]

Agreed.
But what is your reserve for then?

Stages are not reserve any more than the 1/3 or 1/4 that you plan to leave in your tank is. A pony bottle exists beyond that calculation. It is there when your stage gas has been lost and you need enough air to get to the surface. A pony is a supplement to your back gas, not an addition to your back gas.

At least as far as as I know.