Info Are Pony Bottles Dangerous?

[SlugLife]

I don't get the practice of pony bottles.

It only matters if it works for that diver and the dive in question.

I'll explain my own benefit and reasoning, which of course applies to me and my dives. Sometimes I do (a) regular sidemount, sometimes I (b) replace one of the tanks with a pony bottle.

Regular Sidemount

Regular sidemount is great for deeper and longer dives. I have redundancy, but I also have a lot more gas. I can use "normal" sized bottles, which are easier to find on the used market, and even rentals tanks. I can even use the same 2 bottles to do multiple dives, sometimes 2, 3, or even 4 dives on a single pair.

Pony
The pony bottle, which is effectively unused outside of practice and emergencies is obviously primarily there as a kind of life "insurance." Yes, it's in my way, yes, it's ideally never used, yes it's something extra to carry. But the advantage of something like a 19cu pony over a 40cu "dive extender" is that the pony is always (nearly) full, always available, and it's relatively small, light, and minimal bulk. I know exactly what the limits of it's redundancy are for me. The pony bottle (compared to sidemount or doubles) is far less weight, especially on the surface, whether that's on the boat, up-or-down ladders, stairs, or even what I have to drag to-and-from my car.

A lot of my dives are relatively shallow, off my friends boat, and at places party boats like to hang out .... which means LOTS of waves. Climbing up a boat ladder with 2 full sized tanks, if I'm not careful, means a sore back for a couple days. Why take my full sidemount tanks, deal with the extra weight and hassle, when I can often do an hour dive on half an 80cu tank.

you're better off with 10 liter doubles.

If I had an unlimited budget, I'd probably run sidemount 2x 50cu. The problems are (a) I'd have to buy the tanks new, because I never see that size used, and (b) it would double the cost of fills, because around here they charge by the tank, no matter the size of the tank, and (c) I live a long way from the nearest dive shop, so I'd need multiple sets of mini doubles, or my own compressor.

 

[Angelo Farina]

A pony is an "add on" to normal equipment, to be added just when needed.
I own a pony, but I used it very rarely, and only a lot of years ago, for "demanding" dives.
It was added without modifying my main tank, which was either a 9+9 liters twin at 200 bar or a 15-liters single at 232 bars. In both cases with two separate valves, two independent regs and reserve, which is already a decently-redundant setup.
But when diving with deco and very deep (more than 50m) or in deep caverns, an additional pony (3 liters) gave me some backup in case of failures or misplanning.
I never had to use it, indeed. So perhaps it is just a psychological thing, making your more relaxed and confident.

 

[34109411]

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.

double are for technical diving and require a technical training. I don't need double for the recreational diving that i do. I carry a pony bottle for redundancy. i don't do wreck i don't do cave or deep dive or deco dive. Why should i use double ?

 

[34109411]

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.

i thimk you nail it this is exactly my situation.

 

[34109411]

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.

exactly

 

[Angelo Farina]

double are for technical diving and require a technical training. I don't need double for the recreational diving that i do. I carry a pony bottle for redundancy. i don't do wreck i don't do cave or deep dive or deco dive. Why should i use double ?

???
Properly sized doubles are great for rec diving. At my first diving course we only used doubles.
They are more streamlined and well balanced than a single of same capacity.
My twin tank is a Technisub Aralu, 9+9 liters at 200 bars. My single tank is 15 liters Cressi at 232 bars. Same capacity, same weight.
I am not a tech diver.
But, for selected, demanding dives, I also used an additional 3 liters pony tank...

 

[34109411]

???
Properly sized doubles are great for rec diving. At my first diving course we only used doubles.
They are more streamlined and well balanced than a single of same capacity.
My twin tank is a Technisub Aralu, 9+9 liters at 200 bars. My single tank is 15 liters Cressi at 232 bars. Same capacity, same weight.
I am not a tech diver.
But, for selected, demanding dives, I also used an additional 3 liters pony tank...

i dont know any agencies who will let you dive with double in regard of obtaining a open water certification for recreational diving from 0 to 42m. If you know one let me know.

So in that sense no matter what, you need to go to some sort of technical diving in order to dive with double. (if i am wrong let me know but far as i am concern this how it goes).

In my case i did intro to cave diving both with IATD and NACD but didn't finish the full course will i did practice a lot after that with double.

I think padi offer the tech 40 course in order to use double. prerequisite is AOE if i am not wrong.


Personally i find that double are not for everyone anyway.. Unless you are very skills and complete diver.

 

[FishWatcher747]

Even easier to fly with sidemount gear.

Serious question. If someone was interested in trying sidemount and already had regulators what would be the investment in gear enough to fly to a destination to use it?

 

[Bloody Marvelous]

Serious question. If someone was interested in trying sidemount and already had regulators what would be the investment in gear enough to fly to a destination to use it?

A sidemount harness and a rigging kit for two cylinders. About 800~1,000 bucks. Maybe a couple of LPI hoses if they don't come with the harness.

 

[SlugLife]

double are for technical diving and require a technical training.

I don't agree. Doubles, can be little more complicated than your standard open-water configuration, if it's simply manifolded and you use the same regulator. The only real difference is twice the weight and gas. If your dive plan uses a lot of gas, there's little reason one cannot use doubles.

If you start getting into configurations with a little more complexity, like independent doubles, it helps to seek out additional information and advice, and practice. For example, practicing manipulating the valves of each tank, and making sure you can flawlessly switch regulators. It can also be helpful to learn about hose-routing and ways of retaining regulators when dealing with multiple tanks, which don't require a class, but are likely to be covered in some technical classes.

Where it gets a little sketchy would be self-teaching SideMount. I did "self teach" SideMount, using the materials at SideMounting.com and a lot of free time, though I don't recommend that. (If a brand new open water diver, put on a sidemount kit, and with no training of any kind jumped off the side of a boat, I'd consider that dangerous.)