Pony bottle questions

[MikeS]

awap once bubbled...
30's are pretty much neutral so it should disappear in the water from a trim standpoint.

The spec for a luxfer is 1 pound negative when full without a valve or regulator. I measured my stage slung with an Apex DS4/TX40 with a Suunto SPG as 4 to 5 pounds negative when full.

Mike

 

[Genesis]

If I have a buddy, I don't need the pony! He has gas, remember?

The point of the pony is as an "aw s$%t" bottle when you are separated (either intentionally or otherwise) and there is a catastrophic problem with your normal backgas supply.

If you ALWAYS have a buddy, then you don't need a pony. If you think you do, you need DOUBLES!

Therefore, there is no "signal and start ascent" thing, at least not that gets you in gas trouble. If you can get to your buddy, then you don't need the pony any more.

But, when spearing, we are often effectively diving solo. If there is a problem with gas supply at depth, I'm not looking for someone else. If they're not IMMEDIATELY available I am going to use the pony and ascend immediately - no "2 minutes to figure it out" stuff. I do not consider running out of gas a realistic scenario (since such should simply never happen); the pony is there exclusively to cover an "oh oh" problem with my first stage, or something equally ugly like a blown burst disc or blown LP hose.

Therefore, I am comfortable not allowing the 2 minutes to "signal", because if I can do that and coordinate an ascent, I can also grab my buddy's octo and not need the redundancy in the first place.

For "looking around" dives with a buddy, I do not take the pony. I don't need it. Its when diving where I EXPECT that separation is a realistic risk, due to the dive plan itself, that I want the redundancy.

 

[Razorblade]

okay, so if we're diving at 130 ft or so one should need at least 19 ft^3, if margin is desired then a 30. That's almost half the capacity of an 80! (duh) Why not just go directly with doubles? You have two completely independent air supplies with two regs and octos, isn't that right?

 

[Genesis]

In short for why not use doubles.

Yes, its an option. And beyond 130', its the only "wise" choice.

But doubles are HEAVY. Even if you make them up from HP100s, they're STILL heavy, and further, you actually lose one form of redundancy (the ability to detach the "extra" supply and either hand it off or use it without the rest of your gear if it becomes hopelessly fouled for a free ascent.)

Doubles are a choice, and below 100' the balance sways slightly in their favor. I may configure up a set (I have the stuff to do it) this summer and try them to see if I prefer them or the pony, but I suspect that I'll stay with the pony for my "no-deco" dives, simply due to having to lug the doubles around on the surface being a significant PITA.

 

[MikeS]

Razorblade once bubbled...
okay, so if we're diving at 130 ft or so one should need at least 19 ft^3, if margin is desired then a 30. That's almost half the capacity of an 80! (duh) Why not just go directly with doubles? You have two completely independent air supplies with two regs and octos, isn't that right?

That’s a good question. First off, I dive HP120s rather than AL80s so a set of double AL80s would not significantly increase my air supply HP120 + AL30 Pony = 150 versus 2 times 77.4 = 154.8. I would make the argument that you should not count the 30 cubic feet of the pony in the gas supply as it is only for bailout. But with the HP120s diving Nitrox I am typically hitting the NDL or just plain getting board on shallow dives, before I reach the level of air to get myself and my buddy safely to the surface, so what is the point of additional gas?

There is a significant cost difference. In order to partake of two dive boat trips you would need two sets of doubles. The cost of the regulators is a wash. A good set of doubles with an isolation manifold could cost about $1,000 each so two sets that’s $2,000 plus now I need an explorer wing that’s another $457 so the total would be $2,500. Plus there is the cost of additional training in how to correctly manipulate the valves, not sure how much that would cost. I bought the two PS HP 120 for $200 each and the pony for $120, so $520 versus $2500.

My decision is based solely on no-decompression, no-overhead diving. In that environment I cannot justify the additional expense for very little gain.

Mike

 

[MikeFerrara]

MikeS once bubbled...



There is a significant cost difference. In order to partake of two dive boat trips you would need two sets of doubles. The cost of the regulators is a wash. A good set of doubles with an isolation manifold could cost about $1,000 each so two sets that’s $2,000 plus now I need an explorer wing that’s another $457 so the total would be $2,500. Plus there is the cost of additional training in how to correctly manipulate the valves, not sure how much that would cost. I bought the two PS HP 120 for $200 each and the pony for $120, so $520 versus $2500.

Mike

One set of doubles should get you through two dives.

 

[redacted]

Local dives tend to be boring or shallow. It's hard enough trying to get your money's worth from an Al 63.

Flower Gardens live-aboard requires use of their AL80's for nitrox. You can dive doubles, but its air only. Not going thru that butt whipping again.

I guess you could bring your own manifold to Cozumel and talk the local dive operator into rigging doubles, but they'd probably be Al ... and why?

A small pony works fine in all those situations for this wimpy recreational diver..

 

[Braunbehrens]

nikyyo once bubbled...
I will be going to LP to buy a pony bottle this week and would appreciate some input from the board as far as how big, the bracket to use and first stage and second stage reg. Will any reg do? I have a SP mk25/s600 as a primary now and an r380 for an octo. Also< i'm unclear as to how I will be able to read the psi on the pony since it will be mounted on my back. How does that work? I'm thinking about a 19 cu bottle. Would there be any problems getting that on to a plane do ya think? I've read that some peple have the hose wraped around the pony. I don't understand that as how do they access the bottle when it is stapped to your main tank...I must be missing something. Thanks.

Hi. I used a pony bottle for a few months, and went through a variety of mounting options. The best one, without fail, was the stage bottle style. You can do this yourself with a hose clamp and a bolt snap, and you'll find instructions for that on a couple of different sites such the www.wkpp.org site. You'll need a couple of D-rings to attach the bottle to your BC, I just used zip ties to attach a D-ring to the left strap and to a hose holder on my left hip.

I used a 14 chft bottle, and I used it as bailout only. I would breathe it on many dives, not because I needed it but because in an emergency you need to be able to do something without having to figure it out for the first time. It will also tell you if you have enough gas. My SOP was that on a dive where I had plenty of gas left I would switch to the stage (pony) just prior to the final ascent.

I used some surgical tubing to hold the regulator in place. I was very careful to do it in such a way that simply tugging on the second stage would deploy the regulator.

Any good regulator will do. It doesn't matter. Just turn the adjustment screw all the way down. At the beginning of the dive the regulator should be charged, and then the bottle should be turned off so that you don't loose your gas.

No offense, but mounting a pony on your back makes no sense whatsoever. You can't get to the valve, and it's an entanglement hazard.

I stopped using a Pony because I realized that any dive where a pony is needed is really a dive for doubles.

Doubles have a lot of advantages over two single tanks...for example, if you leave 1/4 of your gas in your first tank, this gas is now useless for your second dive. With doubles that gas is still in your tanks, and you can avail yourself of it for the next dive.

-Paul B.

 

[Razorblade]

Is it that difficult to mount two tanks together? In other words: taking four tanks with one manifold, dive with two then surface, disassemble the tanks, link the other two together and dive again is not an option? Is it too much of a hassle?

What do people think about diving doubles with Luxfer's new high pressure AL105's? They're about the same size and lighter than the AL80's with an operating pressure of 4350 psi.
I know that the problem with those is getting them filled unless you have your own compressor, but don't you think that in the future more and more places would have the ability to fill them to capacity?

 

[faye]

taking four tanks with one manifold, dive with two then surface, disassemble the tanks, link the other two together and dive again

BAAAAAAAAAD idea.

operating pressure of 4350 psi.

Hard enough to get a cave fill in my area