Pony Recommendations

[ClayJar]

If you do the numbers, 19cf should get you up from "recreational" depths at standard 30fpm ascent rates, including deep stops and a safety stop at 15' without a problem, even when you're in a significantly stressed breathing state, assuming "significantly stressed breathing state" means your SAC is about 1cfm.

If you're at the deep end of the depth range, the high end of stressed, or the hooverian end breathers, there is a chance you could be pushing the limits of a 19cf pony, which would certainly not be the case if you were carrying a 30cf pony in the same circumstances.

For me, my SAC is amply low and my dive profiles are amply conservative (i.e. no overheads at 120', to say the least) that I am quite comfortable with my 19cf pony. If I add a few complicating factors (deep dives with possible entanglements or whatever), I'll pick up a 40cf (since the size difference between a 30cf and a 40cf isn't much for 33% more air).

A simple way to get a rule of thumb feel is to look at the equivalent PSI in an AL80. In rounded numbers, a 13cf is 500psi, 19cf is 750psi, 30cf is 1125psi, and 40cf is 1500psi. (...6cf is 225psi, 3cf is 115psi, 1.7cf is 65psi)

 

[Curly]

I use a steel 3 litre @ 230 bar or 24cf. As for the reg I have a few to choose from. MK20 and M50 or Cousteau & adjustable micra or Cousteau and XR2.
If you are going to buy one new then try and match it with what you already have or buy something better and use it as your main reg set.
If you are looking at tech in the future the a 30 or 40 could be the better investment. otherwise a 19.

I have the Cousteau & Micra adj -- love that combination, and was thinking of getting another for the pony. It's a great first stage, and the second is very compact and performs well.

 

[Curly]

...

A simple way to get a rule of thumb feel is to look at the equivalent PSI in an AL80. In rounded numbers, a 13cf is 500psi, 19cf is 750psi, 30cf is 1125psi, and 40cf is 1500psi. (...6cf is 225psi, 3cf is 115psi, 1.7cf is 65psi)

I love this information. Nice perspective. I'm leaning toward the 30 now.

 

[Jibeho]

I use an Oceanic DX2 with a Delta 2nd. I sling a 13CF luxfer bottle.

 

[Mr.X]

There are some interesting and somewhat odd perspectives regarding redundant air supplies. Some have mentioned SAC rates, some formulas. As a tech instructor...please consider that you will be most likely using your emergency bottlle because something didn't go quite right. That being the case, consider getting as generous a gas supply as you can carry (slung if possible). At depth and under exertion a 13, 19 tank will only get you so far. I carry 30's, 40's and 80's for different purposes. When the stuff hits the fan it is far better to have more gas than less.

If you're slinging consider a Luxfer vs. a Cat. cylinder. Cats. tend to be butt heavy. I will also add that look at the folks who are put together in their diving and see how they do it. Their processes have evolved over time, or they undertook the necessary training to get where they are and know how to config. related to their diving agenda.

 

[paulwlee]

Many on this list are tech divers who dive doubles and carry multiple 80cf, 40cf bottles for stage and deco bottles, and thus have a skewed perspective. We already have a set of doubles weighing 100~150lbs on our back, so the difference between a 40cf bottle and a 19cf bottle doesn't really seem like much.

This is quite different from someone diving with say a single AL80.

Remember that you will be carrying this extra tank on EVERY dive.
The difference between a 19cf and 30cf tank is quite large in terms of weight and bulk, and you may end up not carrying it around AT ALL if it becomes too much trouble for you.

As Clayjar mentioned above, 19cf is quite good for dives in the vicinity of 100ft.
I used to use one, and they're a great size.

The argument that more is better is flawed. Then why not dive with doubles? It's more gas, and gives you more options when a failure occurs! Where do you stop?

 

[Mr.X]

Many on this list are tech divers who dive doubles and carry multiple 80cf, 40cf bottles for stage and deco bottles, and thus have a skewed perspective. We already have a set of doubles weighing 100~150lbs on our back, so the difference between a 40cf bottle and a 19cf bottle doesn't really seem like much.

This is quite different from someone diving with say a single AL80.

Remember that you will be carrying this extra tank on EVERY dive.
The difference between a 19cf and 30cf tank is quite large in terms of weight and bulk, and you may end up not carrying it around AT ALL if it becomes too much trouble for you.

As Clayjar mentioned above, 19cf is quite good for dives in the vicinity of 100ft.
I used to use one, and they're a great size.

The argument that more is better is flawed. Then why not dive with doubles? It's more gas, and gives you more options when a failure occurs! Where do you stop?

The primary purpose of bailout is when things go hairy and gas is needed to get you, or possibly others to your next stop, or surface safely. As techies we carry bailouts based on need(s). These needs are certainly skewed towards expedition-class work and may exceed the needs of the rec. diver. However...the thinking is sound. Consider needs* first, weight/drag/inconvenience as a secondary factor. The difference between a 13, 19, 30, or 40 can make a difference to some, but in many cases is only nominal. I've slung 30's, 40's on petite and teen divers. Most often than not the teen diver finds these sized bottle to be of no signficance weight, or size wise. Given the opportunity, they were more than happy to sling extra gas.

Let's be serious. If a diver can't make a walk down Monastery with their single tank, or up the hill with a 30 we're talking someone who needs some work in the gym.

Before making blanketing statements consider that in worse case scenarios that an anxious diver can empty a little 13, or 19 in no time flat at depths greater that 60. Seen it happen several times in various contexts. Again, assessing needs first is where you begin. If some are considering venturing towards the technical area- get training. Prior definitive statements without real-world experience is leaning towards scary in my book.

 

[Curly]

I'm leaning toward the 30. After all, the purpose is to have a reliable (and ample) supply in the event something goes wrong. If I'm using the pony at all, it will most certainly be on a wreck where the boat or common sense requires a redundant air source. If I'm farting around in my home lake or the local quarry, no need. Solo work in the lake (moorings, etc.), it's smart. Recreational bottle hunting ~20-50 feet with a buddy...no need.

Many thanks for all the great info.