NE Pony/Stage 30/40

[MacLeod]

I've never used a pony before, but it appears that most of the local boats (NY,NJ) require a redundant air source. This of course means a pony for those not diving doubles.

I have been debating with whether to get a 30cuft cylinder (which I understand is quite common) or a 40. While the 30 might be a bit more convenient size wise, I have been thinking the 40 would be more flexible as it could also make a reasonable sized tank for use as a stage/deco cylinder when not used as a pony.

Is this line of thinking reasonable?

I have seen cylinder dimensions (Luxfer: 30cuft-D:4.88" L:21.9" WT:11.6# ; 40cuft-L:5.25" L: 24.6" WT:15.3#) ...but "in-person" (to carry), is the 40 that much larger to deal with?

Finally, I know it is a point of debate, but what do you recommend as the better trim method of carry...slinging like a stage or bracketed to back gas?

Thank you!

 

[pdoege]

If you can get away with an H-Valve, I would do so.

40s are pretty big. I do know at least one person who carries a 40 as a pony. She attaches it to her tank with a pony-tamer.

Peter

 

[MrSquid]

Most divers I see on NE charter boats are diving HP100's or HP120's as doubles. Those who do dive singles are back mounting 30cf bottles. Occasionally I see back-mounted 40s. I have yet to see someone sling a pony in this area. Not saying you shouldn’t, but other divers will probably lecture you about not having your deco gas labeled and doing deco without doubles.

 

[salty]

A stage bottle= used to extend bottom time
A deco bottle= contains high O2 gas used for accelerated deco
A pony bottle= a redundent source of back gas used when things go bad.

For diving the NE i would recoumend a 40cf. I dont know your skill level so Im sorry if i guess wrong but I will assume that your relativly new to advance diving.

For rigging I sugest not back mounting but carrying like a stage/deco bottle. The reason is that it is easy to see and manage vs a bottle straped to your back it is also more streamline. Be careful how you rig it metal to metal conections are a no no. You also want to have it close to your body not hanging a foot away from you when your in the water.

Going back to sizes, if your using this as a ponny you want something light, but with a good amount of gas compairing a 30 to a 40 the only diffrence is 10 cf of gas and a few inches in length. You wont notice the length in the water. If you need to go to your pony that extra 10 cf will be appreciated. Also if you move on in skill levels to deeper and longer dives and start using the pony for a deco bottle the 40 is better so you might as well get it now.

I would not use or call a 40 a stage bottle its just too small to be any real use for a planned stage dive, I use al 80's for stage diving.

I hope I answered your questions, there are many more details to cover but picking a size is the first step.

 

[DA Aquamaster]

I used to carry a 30 cu ft pony attached to the main tank. I don't completely agree that slinging it like a deco/stage bottle is any more streamlined but a lot depends on how you rig it in either case. A badly rigged stage bottle or a back mount with badly routed hose(s) both add drag and snag potential.

It is easier for a newer non-technical and not technical equipped diver to back mount it. It is out of sight and largely out of mind and properly done is just as low drag although arguably a bit more prone to snagging on monofilament, net, etc. as it is back where you cannot see it. But then in those cases you are also likely to snag your main tank as well.

Carrying a pnoy like a deco bottle takes a little practice and a little getting used to as the front of the diver is no longer uncluttered and the weight and balance of the whole system is potentially a bit more asymetric. It also requires a B.C. or harness with properly located D-rings. Not a problem with a backplate and wing but potentially a fatal flaw with many B.C's where back mounting may be your only real option.

If you back mount, run the hose over the right shoulder and clip the second stage closely to you where you can access it with either hand. I like to use an 1/8" O-ring from the local hardware store plumbing department that is just large enough to fit snugly around the base of the mouthpiece. Then use a small zip tie to attach it to a bolt snap that is then snapped to an appropriately located D ring on your B.C or harness. (do not use boat snaps as they will reach out and grab things).

A bolt snap/o-ring combination keeps the second stage attached closely to you and ensures it is still easily accessible. If you have the time you can unclip it or, if you or your buddy need it right now, the mouthpiece will slip through the O-ring with a light to moderate tug. With a snug 1/8" thick O-ring it is very rare to have one come undone during a giant stride, and if it does it is easy to slip the o-ring back over the mouthpiece even in gloves before you start your descent.

In my ignorant and stupid days I used to use a fastex buckle o-ringed to the second stage as there was a corrsponding fastex buckle on the B.C. I had at the time which unfortunately was not ideally placed as it was a bit hard to reach with one hand and impossible to reach with the other. Then to make it worse, I broke the o-ring right before a dive and got the bright idea to just zip tie it on as a one dive fix. It turned out to be the wrong dive to do that. It's amazing how hard it is to undo a fastex buckle tied directly to the second stage in heavy dry gloves in an awkward head down and cramped position when you have been out of air for awhile. I damn near drowned over a 29 cent o-ring. It was down to "If I don't get it right this time I am going to die right here." which was oddly rather calming. Still, I don't reommend it for stress relief and I don't do that anymore. I do recommend keeping a few spare o-rings in the save a dive kit.

The other valid alternative is to attach the second stage around your neck with surgical tubing in a more technical fashion. It has a lot of advantages but takes some additional care in hose lenght and routing.