What's the difference between a stage and a pony?

[FreeFloat]

No flames here.............please

Just an honest question: what's the main difference between a stage bottle and pony?

I have a bunch of ideas, things such as physical size, how it's mounted, its role in the gas plan (or not), whether it's left behind or not, etc. but I'll save speculation until after I have a few replies. It seems any time I think I have it figured out, I see someone with a tank that defies my definition.

Anyone?

 

[Green_Manelishi]

No flames here.............please

Just an honest question: what's the main difference between a stage bottle and pony?

I have a bunch of ideas, things such as physical size, how it's mounted, its role in the gas plan (or not), whether it's left behind or not, etc. but I'll save speculation until after I have a few replies. It seems any time I think I have it figured out, I see someone with a tank that defies my definition.

Anyone?

Greatly simplified ...

A "stage" bottle is staged (carried and dropped off), or carried throughout the dive as a source of gas for a particular "stage" of the dive. It might or might not be a source of deco gas.

For example you might have a stage bottle that is used between the surface and 'x' feet at which time you switch to a different stage bottle or your back gas. The order is reversed during the ascent.

Where these are typically used is for deep/long dives involving wrecks or caves.

A "pony" bottle is typically used as an alternate/redundant source of gas if your primary source fails. Most usually used by recreational divers. Tech types don't use "ponys"; they use doubles and stages.

 

[MikeFerrara]

A stage bottle is used to extend the length of the dive by increasing the gas supply. AL 80 tanks are often used and typically slung on the side by the shoulder and hip d-rings. A single second stage and an SPG on a short (6 inch) hose are all that's usually on the first stage. There are a couple of different ways to manage the gas supply but the simplest to explain is the rule of thirds. In this case 1/3 of the gas in the stage is used before switching to another stage or back gas. On the way back a second third is used leaving the last third in reserve incase there is a delay or you or some one else looses a stage. In caves we drop the stage when we switch off of it and pick it up on the way back. In OW we generally keep all of our gas with us (including decompression gas). I prefer not to use stages in OW for that reason and usually limit dive times to what we can do on back gas (with decomrpession gas also of course. Cave dives are often longer just because of the distance envolved in getting to where we want to go.

A pony bottle is used strictly as a backup supply and they mount them all kinds of ways. I haven't ever had a need for one and don't think I ever will.

 

[FreeFloat]

So with a stage, then, it'll typically contain a different gas mix than the backgas.

Is there any time when a stage - left behind or not - will contain the same gas as backgas?

 

[Atticus]

So with a stage, then, it'll typically contain a different gas mix than the backgas.

Is there any time when a stage - left behind or not - will contain the same gas as backgas?

I'm somewhat out of my depth here not as I don't typically stage (drop) bottles, but an example of where the stage may contain the same as back gas would be where you are travelling a great distance at the same depth.

If I recall correctly this is done in long shallow cave systems. The backgas is the same as the stages since everything is intended to be breathed at the same depth. I have no personal experience with this.

 

[Mako Mark]

a stage bottle is used for extending the divers gas supply, a pony is a horse the size of a donkey....

 

[Green_Manelishi]

So with a stage, then, it'll typically contain a different gas mix than the backgas.

Is there any time when a stage - left behind or not - will contain the same gas as backgas?

Yes. As Mr Ferrara stated in his post. Using multiple stages (see www.wkpp.org for extreme examples of stage diving) you can breathe from one, drop it when it is 3rd full, start another, etc. etc. etc. Traveling exclusively on stage(d) bottles you can preserve BG for emergency use.

 

[roakey]

So with a stage, then, it'll typically contain a different gas mix than the backgas.

Is there any time when a stage - left behind or not - will contain the same gas as backgas?

Strictly speaking, a stage will almost always contain the same gas as your back gas.

There's really three terms that should be defined: A "deco bottle" that contains special mixtures of gas used for decompression. So a deco bottle doesn't contain the same gas as your back gas.

The strict definition of "stage" or a "stage bottle" *is* a gas the same as your back gas -- the stage is used to extend the dive.

However, we muddy the waters by typically referring to deco and stage bottles collectively as stage bottles.

And a pony is used only in an emergency to self-rescue from an OOA situation.

So another way to look at the difference between a pony and the wider definition of stage is that using a stage is part of the dive plan, but using a pony isn't.

Roak

Ps. And yet another definition of a "pony" is simply a smaller bottle than a normal AL80, for instance. But using that definition really confuses the issue because then you have "a pony deco bottle of O2 slung as a stage." Don't go there.

 

[Green_Manelishi]

However, we muddy the waters by typically referring to deco and stage bottles collectively as stage bottles.

and we further muddy the waters if our deco bottle is a small pony bottle that we "stage" intending to pick it and then we can't find it and then .....

 

[FreeFloat]

and we further muddy the waters if our deco bottle is a small pony bottle that we "stage" intending to pick it and then we can't find it and then .....

ROTFL!! :rofl: