Looking to get a pony tank

[mstallmann]

I am a recreational diver, going through the PADI divemaster and assistant instructor courses, and am looking to step up my level of safety. I am also looking at doing some shallow wreck diving and may dabble in tek diving in the future...

but anyways, I was looking to get a pony bottle to strap to my tank...I currently have an integrated octo on my inflator....not good to have while training people, so the pony will offer me the octo, and the redundancy.

now to my question, what size pony tank is adequate, and is a pressure guage necessarry for it...keeping in mind my other diving adventures....what are some good suggestions for brands, configurations, etc....while trying to keep costs down

thanks in advance...mike

 

[sylvester]

My pony set up as a rec diver is for redundancy only, although I have a Octo I carry a 30 cf pony, only when I am diving deeper then 60ft, or the water is cold. There is no written reason for my choice of 60 ft just my personal preferance, since that is where a CESA begins getting challanging. My pony is for bail out only. If I have to switch to the pony or hand it off the dive is called. Up to this point it has not been used for real yet just practice. However I like having a silent buddy under my arm.

I choose the 30 cf pony because even at recreational depths it provides sufficent air to work though a problem and surface with out having to worry about not having enough air, and sucoming to stress when you need a clear head.

My pony is slung like a stage after reading this board for a while, I started with it on my back but the slinging it makes more sense to me now after trying both ways. I have a pressure gauge on my pony on a 6" hose, I used to use a small dail gauge on the first stage, but the regular pressure gauge is easier to read. You will want a gauge how else will you have the piece of mind knowing you have a full pony at a glance. My reg is a scubapro mk20 UL, and a g250 2d stage. I picked the 2d stage for logistics its the same thing I use as an Octo off my main tank.

I hope this helps, if you use a pony do plan on using it as part of your dive. If you have to use, its time to go.

 

[Scubaroo]

Seeing as you have to spend money on a second reg for the pony bottle anyway, why not just switch to doubles? Get something light like a pair of 72s or something.

Pony tanks have no real place in technical diving, so don't buy something you can't use down the track. If you want to up your level of safety, invest in a course that teaches proper gas management.

 

[Scubaroo]

sylvester once bubbled...
if you use a pony do plan on using it as part of your dive. If you have to use, its time to go.

NO!

Never consider a pony as part of your dive plan. If you choose to carry a pony, it's for bailout in an out-of-air emergency, not to extend your bottom time or use as a crutch to rely on because of poor dive planning.

 

[sylvester]

That last line should say DONT plan on using it as part of your dive plan. Not do. My typos are bad tonight

 

[sylvester]

Thanks Scubaroo, you are on the ball and ovu=iuosly fast on the keys too.

 

[drbill]

Agree with scubaroo. I have a 13 cu. ft. pony strictly for bailout. Never had to use it... until the day I went deep and didn't carry it out of sheer laziness.

I carry mine on my back because slinging it gets in the way when I'm videotaping on the bottom. Because of this I slightly counterweight the other side of my body. Otherwise slinging it may be a better option.

Personally I would never consider more than a 20 cu ft as that is PLENTY to get me out of trouble given my dive profiles. Yours may vary.

Dr. Bill

 

[paulwlee]

I also used a pony for the past couple years. I found that you would probably need at least 19cf for it to be useful. What's more, the difference in weight between the 13cf and 19cf isn't that noticable. The next step up, the 30cf, is too large unless you are using it for a stage bottle. So the 19cf was a natural choice for me.

I did the calculations, and found that 19cf will give me just enough air to give me two minutes to sort things out at 100ft, a 33ft/min safe ascent and 3 minute safety stop, provided that I have a 1cf/min SAC, for stressful situations. A 13cf will be pushing it, as you just barely get 1min of bottom time and no safety stop, so no room for error, with the same parameters.

I tried various attachment choices. Tank mounting is nice because it's totally out of the way and you don't notice it. But you usually have to leave the valve opened, and if you get entangled you probably need a buddy's help to get free. For this choice, I found the Tigermount pony bracket to be the best out there, albeit a little expensive. You can hand it over to a buddy with a little practice, and changing tanks is very easy.
An alternative is to sling sideways in front of you, as a tech diver would do a deco/stage bottle. This way, you can pressurize the bottle and turn it off, preventing accidental gas loss. It's also easier to hand off, or disentangle yourself. But it is a little less comfortable than tank-mounting, although once you get used to it, it's OK. 19cf upwards can be slung this way.
I used mine both ways, and there are likes/dislikes for both. It will probably be a personal choice.

As for the pressure gauge, one can argue that you don't need it, as when you are using it, you should be on your way up and you try to do a safety stop as long as you are still getting air. But it is nice to have one, as you don't have to put another regulator on it to check the pressure before you enter the water. I had a small button gauge on my pony reg for this purpose.

There were a couple threads on this a while back, so do a search, but I think the consensus is that you need at least 19cf, and then there is the debate about tank mounting vs. stage slinging.

BTW, I am just moving to diving doubles, and don't need the pony bottle and bracket any more. PM me if you are interested in them. (We seem to be in the same neighborhood, so you can check them out if you'd like.)

 

[DA Aquamaster]

I support the opinion that 19 cu ft should be the minimum and 30 cu ft the minimum for deep diving and if any deco is involved. Of course if you are doing planned deco, you really ought to seriously consider using either independent doubles or manifolded doubles and rule of thirds air planning.

I used a 30 cu ft pony for recreational diving and it remains in use as a slung deco bottle. A 19 cu ft tank will just end up sold on E-bay if you get into technical diving as it is too small for any practical use. A 40 cu ft pony is even more fuctional as a slung deco bottle and is the same diameter as a 30 cu ft pony but is almost as tall as a steel 72 and which makes it too bulky for pony purposes.

I currently dive with steel 72 independent doubles on every dive, technical or recreational. It adds redundancy on every dive and allows me to maintain the same configuration on every dive. Using two steel 72's allowed me to take off a lot of weight and in the end, the total rig including weights was not much heavier than a single tank and 30 cu ft pony, so it makes no real sense for me to use a pony.

Some of the recreational divers I dive with like the idea and regret having invested in a pony bottle with it's limited uses. For you what you spend on a pony you can go with a set of travel bands (assumng your BC will support doubles) and use your existing tanks and valves in an independent doubles set up. You then can dive it with rule of thirds planning and gas switches on deeper dives or dive off one side and use the other as what amounts to a super pony on recreational dives.

I have not had any significant problems with the assymetric weight that results when breathing off only one tank as it is all fairly close to center and is not noticeable underwater unless you are completely motionless in the water for several seconds. In that case you will slowly roll over a bit toward the end of a dive But this can also be reduced substantially by moving a few pounds of weight (half the swing weight of the tank) to the opposite side. It reduces the maximum assymetric weight by half and leaves you well trimmed through most of the dive.

With independent doubles you will want an SPG on each tank for air management purposes.

 

[mstallmann]

Thank you for all of your responses...just to reply to a couple of the first ones...I never intended using the pony for planned dives. It would only be an added safety. I think I will go with a 19cf or 30cf, depending on size...I like the idea of doubles, but my BC doesn't do doubles, and I don't want to get a new one. Maybye when I get a new BC, I will consider it.

Again, thanks for the detailed responses....mike