Info Are Pony Bottles Dangerous?

[SlugLife]

After years of resisting, I am now a convert.

PONY BOTTLES ARE INDEED DANGEROUS.

I dropped a pony bottle on my bare foot, and you should have heard me squeal.

That's why 1.7cu Spare Airs are superior!

I get ragged on for using a J Valve.

I don't really care about diver's gear choices. But I might rag on you if we're friends anyway.

 

[Angelo Farina]

What a J valve cannot do is provide redundancy to mitigate a catastrophic failure of your primary system.

The J Valve also has the problem of a potential for the "lever" to be inadvertently or accidentally actuated.

A J valve can provide some redundancy in case of primary reg free flowing (or O-ring extrusion) and emptying the tank quickly, before you manage to close the affected valve.
When you finally manage to close it, you pull the reserve and breath from the other independent reg.
I have seen this happening to another diver just once, but it happened..

And regarding the problem of accidentally pulling the reserve rod, this cannot happen with the Technisub patented spring-loaded reserve mechanism, as in my Aralu twin tank built in 1973.
If you pull the rod before the reserve engages, nothing happens and the spring brings back the reserve in the "closed" position.

 

[Waterwulf]

That's why 1.7cu Spare Airs are superior!


I don't really care about diver's gear choices. But I might rag on you if we're friends anyway.

I would accept it in fun and return it with the same.

 

[Bloody Marvelous]

I don't get the practice of pony bottles.

You're carrying an extra cylinder of gas that you have no plans of using. If you've got a 12 liter cylinder and a 7 liter pony, you're better off with 10 liter doubles.

If you're switching to Nitrox, you need to bleed down your pony and have it refilled. On doubles you'll have the same gas in both cylinders.

If you want to dive with multiple gases, you should have stage cylinders.

Doubles can provide full redundancy, and you don't need to add a 3rd second stage.

You can't accidentally have your redundant air supply turned off on doubles. If you do, you'll notice quickly that you're breathing down your cylinders a lot faster than expected, or if you have an SPG on one post and a transmitter on the other, you'll notice that you're only breathing down one cylinder.

I can't see any benefit to having a pony bottle over having backmounted manifolded twins, stage cylinders, or sidemount.

 

[FishWatcher747]

I can't see any benefit to having a pony bottle over having backmounted manifolded twins, stage cylinders, or sidemount.

1. Weight

 

[Bloody Marvelous]

1. Weight

Are a main cylinder + pony that much lighter than doubles with similar capacity?

 

[FishWatcher747]

Are a main cylinder + pony that much lighter than doubles with similar capacity?

I can't fly with mini doubles. I can fly with a 19 cu ft , 3L pony

 

[Marie13]

I don't get the practice of pony bottles.

You're carrying an extra cylinder of gas that you have no plans of using. If you've got a 12 liter cylinder and a 7 liter pony, you're better off with 10 liter doubles.

If you're switching to Nitrox, you need to bleed down your pony and have it refilled. On doubles you'll have the same gas in both cylinders.

If you want to dive with multiple gases, you should have stage cylinders.

Doubles can provide full redundancy, and you don't need to add a 3rd second stage.

You can't accidentally have your redundant air supply turned off on doubles. If you do, you'll notice quickly that you're breathing down your cylinders a lot faster than expected, or if you have an SPG on one post and a transmitter on the other, you'll notice that you're only breathing down one cylinder.

I can't see any benefit to having a pony bottle over having backmounted manifolded twins, stage cylinders, or sidemount.

Recreational divers on the Great Lakes will commonly carry a pony for deeper dives. Note they are recreational divers with single tanks. They maybe do a few charters a year. Do warm water trips, too, plus other diving such as quarries and inland lakes. Why should these divers who have no interest in tech diving go to the expense of setting themselves up with doubles or sidemount for a few dives a year? A pony is a lot cheaper and a lot lighter to carry than a set of doubles.

I used to be one of these single tank divers slinging a pony - 40cft in my case.

And there’s no need to bother with nitrox in your pony. Air only.

 

[Gandalf-the-Diver]

I've always viewed pony bottles as equipment focused on solving skills problems.

You should always plan your dives, plan gas consumption, and practice emergency drills.

If you're a rec diver, you must dive with a buddy who will be your first source of assistance shall you end up running out in emergency (e.g., a critical first stage failure). A pony bottle on a rec dive may give you a false sense of security or let you cut corners.

If you're a tech diver, you probably have doubles/sidemount/ccr and know how to stage, so the pony is not useful.

A pony bottle, is not intended to solve skills problems. They can however, do that by the simply being available when you need it; in that case, usually due to diver error. A pony bottle, is NEVER included in one's dive planning.
A rec diver, does not always have to dive with a buddy; it's called Solo or Self Reliant certification. A self reliant dive buddy, makes the best buddy. I have been slinging a pony bottle, since my 1st dive as a cert OW diver. I even slung it during my AOW course. 1st pony was a 13cu Catalina; sellers regret for selling it when I got a 30cu Catalina I know, when I am at 130', my 30cu pony, when full, will bring me safely to the surface. I also knew, my 13cu pony, if I was below 60', would get me to a buddy, not the surface. Either way, it was only to be used, during a primary gear failure, and never used to extend a dive.

 

[grantmac]

I can't fly with mini doubles. I can fly with a 19 cu ft , 3L pony

Even easier to fly with sidemount gear.