Pony Bottle / Stage Bottle / Decompression Bottle. What's the difference?

[tbone1004]

Some of us who are part of the “technical community” do consider a pony bottle a “properly redundant configuration” for [U]recreational[/U] diving. It’s a completely philosophical disagreement and to use the term “technical community” as if it speaks with one voice on this subject is just not true. That horse has been whipped but yet the beatings continue.

My hard and fast line of when it's not acceptable is when you still have 2 second stages on your backgas. I would not accept that for an Intro to Tech course nor would I accept it for a solo diving course. If you have a sidemounted or bracketed bottle where it was your secondary second stage, and your only secondary second stage, I would accept it as an alternate configuration for independent doubles. That is not what people think of when they think "pony bottle" and that's why it gets weird when you look at the definition of bailout bottles, safety bottles, and pony bottles. I do not believe that any bottle smaller than 30cf is of sufficient size to be considered a properly redundant configuration though, and if teaching those classes would not accept anything less than 30cf, ideally 40.
I think you would be hard pressed to find any technical instructor who would accept 3 second stages on 2 tanks for any sort of technical class or technical dive or any that would accept a bottle smaller than 30cf.

 

[Divin'Papaw]

My hard and fast line of when it's not acceptable is when you still have 2 second stages on your backgas. I would not accept that for an Intro to Tech course nor would I accept it for a solo diving course. If you have a sidemounted or bracketed bottle where it was your secondary second stage, and your only secondary second stage, I would accept it as an alternate configuration for independent doubles. That is not what people think of when they think "pony bottle" and that's why it gets weird when you look at the definition of bailout bottles, safety bottles, and pony bottles.
I think you would be hard pressed to find any technical instructor who would accept 3 second stages on 2 tanks for any sort of technical class or technical dive.

Pony bottles have no place in technical diving. We agree there. The context is recreational diving. People do swap back and forth between those two worlds.

The belief that a pony bottle is not proper redundancy FOR RECREATIONAL diving is where we disagree. There are plenty of technical divers and instructors who agree with me. There are also plenty who agree with you. This is why I stated it’s a philosophical disagreement and the technical community does not speak with one voice on this.

 

[lowviz]

My hard and fast line of when it's not acceptable is when you still have 2 second stages on your backgas.

@tbone1004: Please clarify.

Do you mean an H-valve, tiny dubs, or full twinset with isolation?

 

[Divin'Papaw]

Here’s just one example from TDI’s own tech blog of someone within the tech community who agrees with me that for recreational diving a pony is a viable redundant air source as are back-mounted & side-mounted doubles.

Diving with redundant air source for recreational divers - SDI | TDI | ERDI | PFI

 

[tbone1004]

@JimBlay author is not a technical instructor. While it may be on their blog, I don't really think that that can be considered anything authoritative. My point is that when the normal person in the industry thinks of pony bottles, they think of a normal backmount singles configuration plus some smaller bottle attached in some way. That normal backmount singles configuration has a pair of second stages. There is nothing acceptable to me about that configuration, especially when the bottle is inadequately sized for a normal ascent *i.e. at 100ft, anything less than 30cf is not enough*. If you remove one of those second stages, I no longer consider that a pony bottle, and it becomes a bailout bottle which I have no issue with.

@lowviz one second stage per first stage. How it is accomplished whether h-valve, manifolded twins, independent twins, sidemount, doesn't matter.

 

[Divin'Papaw]

@JimBlay author is not a technical instructor. While it may be on their blog, I don't really think that that can be considered anything authoritative. My point is that when the normal person in the industry thinks of pony bottles, they think of a normal backmount singles configuration plus some smaller bottle attached in some way. That normal backmount singles configuration has a pair of second stages. There is nothing acceptable to me about that configuration, especially when the bottle is inadequately sized for a normal ascent *i.e. at 100ft, anything less than 30cf is not enough*. If you remove one of those second stages, I no longer consider that a pony bottle, and it becomes a bailout bottle which I have no issue with.

I never said the author was a technical instructor. He is however a technical diver and it was shared on the TDI community blog. If that doesn't qualify as an opinion from within the technical community I'm not sure what does. You seem to suggest that only technical instructors can speak for the technical community? I disagree. You also keep stating the "technical community" as if there is a consensus on this. There isn't. You are sharing YOUR OPINION as a technical instructor. Nothing wrong with that at all. But you're not speaking for the technical community as a whole.

You're also assuming that saying "pony bottle" somehow by default means an inadequately sized cylinder. Not sure why you make that assumption. Many of us that use pony bottles for recreational diving speak regularly about the need for them to be properly sized. I for one have spoken often about preferring an AL40.

Lastly the topic of the number of 2nd stages on the back mounted 1st stage. We've gone back and forth on that on other threads. Not going there again. Anyone can see the other recent pony threads for discussions on that topic.

 

[lowviz]

one second stage per first stage.

Oh, thank you.

That is different than "2 second stages on your backgas".

 

[RyanT]

Hey Gang:

I've followed @tbone1004's discussions regarding not liking pony bottles for a while. At times I've been a little confused and it took me a couple of times reading his post above, but I think I finally get where he's coming from. Tom, correct me if I'm wrong, but if I'm understanding correctly, your concern is that a diver with a single tank has a primary plus an octopus. Then, they have a separate pony bottle with a regulator attached. So now, there are three second stages for two tanks. It's the octopus that's the big issue, yes? In an emergency, a diver could be grabbing for the wrong second stage and I do see where that could be a problem.

 

[Angelo Farina]

@JimBlay author is not a technical instructor. While it may be on their blog, I don't really think that that can be considered anything authoritative. My point is that when the normal person in the industry thinks of pony bottles, they think of a normal backmount singles configuration plus some smaller bottle attached in some way. That normal backmount singles configuration has a pair of second stages. There is nothing acceptable to me about that configuration, especially when the bottle is inadequately sized for a normal ascent *i.e. at 100ft, anything less than 30cf is not enough*. If you remove one of those second stages, I no longer consider that a pony bottle, and it becomes a bailout bottle which I have no issue with.

@lowviz one second stage per first stage. How it is accomplished whether h-valve, manifolded twins, independent twins, sidemount, doesn't matter.

Sorry, I do not follow you here: so, if I remove one of the regs I usually employ on my main tank, so that there is only one primary on it, you are happy. If instead I leave the standard two regs on the main tank (plus the third one on the pony), you are unhappy?
Can you elaborate how REMOVING a reg can be safer?
How can I make use of my back gas if the primary fails and there is no secondary reg on its second post?

 

[lowviz]

Sorry, I do not follow you here: so, if I remove one of the regs I usually employ on my main tank, so that there is only one primary on it, you are happy. If instead I leave the standard two regs on the main tank (plus the third one on the pony), you are unhappy?

I will hazard a guess here as it speaks directly to how I dive.

I assume, correct me if I'm wrong, that @tbone1004 wants only one second-stage on every first stage regulator. This is what I do (always). So, on a single tank, use an H-valve.

Now we get into gas volume. That appears to be irrelevant to his argument as it is up to the solo diver or buddy diver to get it right. Goes unspoken.

The fine point here, for me, is that I dive different OC configs but I always want my secondaries to be the same with respect to where the gas is coming from. Thus two sets of regs (one 'set' = 1 primary and 1 secondary) on my back gas, no matter what size, and a pony that I never touch make sense (to me).