Info Are Pony Bottles Dangerous?

[FishWatcher747]

A full 19cf holds about the same amount of gas that is typically left as a reserve in the main tank and therefore is perfectly suited to replace that reserve especially since I leave at least 200 psi in the main tank at the end of a dive

There is nothing wrong with diving this way but your smaller tank is not a Pony. You are diving doubles with a large tank and a small tank. Terminology matters.

 

[SlugLife]

A full 19cf holds about the same amount of gas that is typically left as a reserve in the main tank and therefore is perfectly suited to replace that reserve especially since I leave at least 200 psi in the main tank at the end of a dive.

There is nothing wrong with diving this way but your smaller tank is not a Pony. You are diving doubles with a large tank and a small tank. Terminology matters.

It's important to use this consistent terminology with pony bottles (and not-pony bottles), because concepts for pony bottles have many assumptions built in. There are many terms one can use for the dive-extender, including a slung-bottle, redundant air, doubles, independent doubles, etc. Pony bottle reverse to how it's used.

An advantage of a pony-bottle, is the simplicity. "I know this 19cu pony bottle is always (mostly) full, and can handle emergencies for me up to 100ft." There isn't much guessing, or room for error, and it's basically always available and always full. When people give advice for pony-bottles, the assumption is that advice applies to pony-bottles, and not dive-extenders.

For example, if someone asks "what size of pony do I need at 100ft" but then starts using that to extend their dives at 100ft, they asked the wrong question and received non-applicable answers, and their redundant air is no longer as useful. However, if you want to extend a dive and also have redundancy, then we're basically talking about gas planning, a larger tank, and making sure both tanks have enough of a reserve to safely surface.

Of course, once one knows what size of "pony" they need at a given depth, it also makes it somewhat easy to figure out how much of an larger tank you could use as a dive-extender. For example, if you need a 19cu pony at 100ft, then you could use about half of an 40cu for dive-extending at 100ft.

 

[Eric Sedletzky]

It's important to use this consistent terminology with pony bottles (and not-pony bottles), because concepts for pony bottles have many assumptions built in. There are many terms one can use for the dive-extender, including a slung-bottle, redundant air, doubles, independent doubles, etc. Pony bottle reverse to how it's used.

An advantage of a pony-bottle, is the simplicity. "I know this 19cu pony bottle is always (mostly) full, and can handle emergencies for me up to 100ft." There isn't much guessing, or room for error, and it's basically always available and always full. When people give advice for pony-bottles, the assumption is that advice applies to pony-bottles, and not dive-extenders.

For example, if someone asks "what size of pony do I need at 100ft" but then starts using that to extend their dives at 100ft, they asked the wrong question and received non-applicable answers, and their redundant air is no longer as useful. However, if you want to extend a dive and also have redundancy, then we're basically talking about gas planning, a larger tank, and making sure both tanks have enough of a reserve to safely surface.

Of course, once one knows what size of "pony" they need at a given depth, it also makes it somewhat easy to figure out how much of an larger tank you could use as a dive-extender. For example, if you need a 19cu pony at 100ft, then you could use about half of an 40cu for dive-extending at 100ft.

As far as I’m concerned, to extend a dive you either need a bigger tank or a set of doubles, simple as that. You need to plan your depth and time with your primary gas only, which may include a reserve as a cushion.
You do not use a pony bottle to extend a dive. It is there as an emergency back up only and is not to be used casually for any purpose other than as a last resort bail out. If that means never using it once your entire diving career then you have a perfect score.

 

[jadairiii]

Branching off another thread, which went mildly off-topic:

1. Are pony bottles dangerous?
2. What are the hazards of pony bottles?
3. What safety advice would you give to someone using a pony bottle?
4. What other advice (sizing, selection, configuration, etc) would you give for pony bottle use?

This is mostly focused on #1, but I've included #2, #3, and #4 to make the thread a little more useful. Given this is somewhat of a debate thread, remember to keep it civil, we don't want the mods to come along with their tools.

As to #1, extremely. When your wife sees the new RB or scooter in the garage and the closest item she sees is a pony bottle, you're getting that up side your head.

 

[SlugLife]

As to #1, extremely. When your wife sees the new RB or scooter in the garage and the closest item she sees is a pony bottle, you're getting that up side your head.

I suppose that's a reason to opt for an AL40, she'd have a harder time swinging it. Or just have a collection of HP130s, you might get divorce papers, sure, but at least not a pony bottle up the side of your head.

 

[KenE]

I have used my AL30 as a pony, small independent double, and sometimes not at all. It really depends on the dive planning. It is always back mounted, primarily because of body shape and it doesn't ride comfortably on the front. If diving with a new buddy it will be there as a pony. If diving with one of my usual buddies it is not likely there at all unless we are going beyond 60ft. Since we welcome anyone to dive with us, we generally have more than just two of us, so available gas is not an issue. However, there are times where I will use the AL30 to extend a dive as a small independent double. This is generally to practice drills, empty the tank for VIP, or just to help match gas consumption with buddies. However, this is a planned situation, not using the pony for something other than its intended purpose.

Making assumptions about other divers is a really bad practice as it can lead to bad decisions underwater. I believe talking during SI about equipment difference helps everyone learn from each other. Not all divers are built the same and limitations may lead to one configuration over another. I always seem to find other solutions to issues I have solved another way, some better, some worse. But what works for me will not likely work for everyone else. And that is why making assumptions is defined as making an ASS-U-ME. It really shows when one makes bold statements on an international board that are not true around the world, and they likely don't have the experience they believe. Dive and let Dive, remember it is for fun, not a competition!

 

[BlueTrin]

There is nothing wrong with diving this way but your smaller tank is not a Pony. You are diving doubles with a large tank and a small tank. Terminology matters.

I don’t understand, if he never uses the 19cf except in case of emergency, why do you object to it calling it a pony?

 

[NW Dive Dawg]

Totally agree with this. If an instabuddy wants to take off, I guess I'm not the ideal buddy. My job as instabuddy is not to chase you. I'm diving redundant so it has now turned into one of my many solo dives.

Totally agree and this is EXACTLY why I so much prefer to dive as a trained, equipped and certified solo diver. I want to be clear that I am not unilaterally apposed to diving with another diver or even a group.......and if I ever recognized an emergency that required my assistance and I was in position to assist I would do whatever I could to help. I simply prefer to make it crystal clear for the record, pre-dive, that I am "officially" diving solo and that there should be no expectation for me act as a buddy and that I have no expectation for anyone else to act as my buddy..

 

[KenE]

I don’t understand, if he never uses the 19cf except in case of emergency, why do you object to it calling it a pony?

If you use the pony to replace your primary tank reserve you lose redundancy. A pony failure leaves you with no alternate source.

 

[BlueTrin]

If you use the pony to replace your primary tank reserve you lose redundancy. A pony failure leaves you with no alternate source.

Ok but you missed the point, the person he is replying to did not say this.