Do you actually see people diving with pony bottles?

[mainedvr]

Here is a scenario, on a dive boat doing some wreck diving in the 80-100' range. Double 100's with a slung 80AL Now not so much for safety as using the 80AL and then switch to your back gas to give you more bottom time staying with in NDL,while still having enough gas in the 100's to do a second dive safely with in the NDL's. The boat does not fill tanks.

 

[MaxBottomtime]

Or use the doubles on the first dive for plenty of bottom time and not having to carry a slung 80, then use the 80 for a second dive.

 

[mainedvr]

Or use the doubles on the first dive for plenty of bottom time and not having to carry a slung 80, then use the 80 for a second dive.

That's a good plan....

 

[Gareth J]

I hadn't realised this thread was still running.

I agree that a pony is for emergency only. It is not part of the air calculation. However, it is useful to calculate how long a pony will last at different depths, at elevated breathing rates.

As an instructor, if teaching ocean diver (OW) on single cylinders I always carried a pony (back mounted). A lot of British instructors do this. It gives me redundancy, and independence. I can concentrate on the student, in the event of an air issue I have enough gas to get me (and the students) to the surface. I am not reliant on the student for rescue.
My kit looks like the students. (Unlike my twinset).
It is very unlikely that the issue will be 'running out of air', however, it is not unlikely that it will be a cold water free flow. (Of which there where a few this weekend).

On the rare occasions I dived single cylinder on dives in the UK I would often take a pony. It ensured I had redundancy. Especially on wreck dives where there is a risk of an overhead environment. (UK diving visibility is variable). Generally single cylinder diving was either for shore dive or small boat diving (RIB's and inflatables).

In the old days a predominantly dived twinsets. (Now I use a CCR). In the early days, when Nitrox wasn't readily available, and site selection might change on the day. We often used to carry 3litre ponies of 50%. This was our flushing gas at the end of the dive on a deco' stop. One 3 litre would generally be good for the weekend, 15 minutes or so of deco (on each dive). It was never part of the decompression calculations, or the air calculations.

Gareth

 

[gcarter]

I agree that a pony is for emergency only. It is not part of the air calculation.

I keep seeing statements like this and I keep shaking my head. It is for emergency only if that is the gas plan. It is not for emergency only if the gas plan includes its use.

I tend to dive larger tanks. My go-to is a HP117, I also have HP130 and HP100s. And I have a couple of AL80s and an AL40.

There is no meaningful gas difference between carrying the AL40 with an AL80 on my back and carrying my HP117. There is absolutely nothing wrong with doing a dive with a gas plan based on using the AL80 and the AL40. Or the HP130 and the AL40.

Or I can take my AL40 on a cold, deep dive for redundancy and not include it in my plan. Same tank. The only difference is the plan.

There seems to be this blind spot that it it is called a stage, its OK to use. If you choose to call it a pony it is not OK to use. Nonsense. There is no magic in calling it a pony that makes it off limits for inclusion in the gas plan.

For the record and IMO, the same holds true whether you are talking about a 40CF, a 20CF, or a 13CF.

We often used to carry 3litre ponies of 50%. This was our flushing gas at the end of the dive on a deco' stop. One 3 litre would generally be good for the weekend, 15 minutes or so of deco. It was never part of the decompression calculations, or the air calculations.

So you planned on using it, yet didn't include it in your plan. Do you not see anything wrong with that?

 

[Lorenzoid]

There seems to be this blind spot that it it is called a stage, its OK to use. If you choose to call it a pony it is not OK to use. Nonsense. There is no magic in calling it a pony that makes it off limits for inclusion in the gas plan.

Then what's wrong with calling it a stage? It's not "magic," it's terminology. Divers have come up with two different terms in order to avoid confusing others as to what its intended use is. If you dive solo, call it anything you want.

 

[boulderjohn]

It's not "magic,"

Yes, it is indeed magic. Here's how a true magician does it.

As you prepare to jump in the water with an AL 40 slung under your left arm, you wave your hand over it and say, "Abracadabra! You are a stage bottle!"

After you breathe half of it, dropping it to about 20 cubic feet, you switch to breathe from your tank, stow the stage bottle's regulator, wave your hand over it, and say "Abracadabra! You are a pony bottle!"

For an extra trick to amaze the audience, when you reach your safety stop, you switch back, wave your hand over it, and say "Abracadabra! You are a deco bottle!"

 

[Lorenzoid]

So long as you're just talking to yourself, sure, you can entertain yourself with that magic.

 

[MaxBottomtime]

Most of the pony bottles I see are 6, 9 and 13 cu ft. Those sizes should never be considered part of a dive plan. The idea of a pony is to get you to the surface if you have a catastrophic gear failure or do something really stupid like not watching your spg. A stage bottle is part of your dive plan, usually containing your deco gas.

 

[teknitroxdiver]

Or use the doubles on the first dive for plenty of bottom time and not having to carry a slung 80, then use the 80 for a second dive.

Then you don’t have any redundancy on the second dive, and you have to have two sets of gear to switch between double and singles. Two reg setups, two BCs, two weight configurations. Using the 80 first gives redundancy for both dives and you use the same gear.