Yoke Valve On Pony/stage Bottle

[CuzzA]

Someone in this thread has had a pony yoke O ring extrude at depth....

I swapped the valve to a pro valve on my pony tank and converted one of my reg sets to DIN. Cost me a $100 total, but the valve on the pony needed replacing any way as I broke it. Eventually I'd like to get everything converted over to DIN, but like you, the expense isn't justified right now. Plus, I have the pony now, so that alone eliminates catastrophic back gas loss being a major issue.

I have my pony on. I think a pony and stage/deco tank can be viewed a little differently. A free flow on a pony shouldn't be a cause of too much concern, it's purpose is redundancy for a catastrophic loss of main back gas while recreational diving (you still have other options). The stage/deco tank on the other hand is gas that is part of the dive plan. I would think a severe loss of stage/deco gas could create issues so eliminating the potential for lost gas is more of a concern and thus the valves are closed.

 

[uncfnp]

I have my pony on. I think a pony and stage/deco tank can be viewed a little differently. A free flow on a pony shouldn't be a cause of too much concern, it's purpose is redundancy for a catastrophic loss of main back gas while recreational diving (you still have other options). The stage/deco tank on the other hand is gas that is part of the dive plan. I would think a severe loss of stage/deco gas could create issues so eliminating the potential for lost gas is more of a concern and thus the valves are closed.

When I first starting carrying a pony the reg did not have a breathing adjustment option and even though it was "detuned" it would still freeflow fairly easily. For multidive days with fills, even top offs inconvenient, I chose to dive valve off. I never found it an issue except for the hassle to make sure it stayed pressurized. Other then diving with no backup reg and intending to use it for an OOA diver, I think think of no emergency where I would not have the few seconds it would take to open the valve. Plus practice, practice, practice.

Now I have a second stage that can be manually adjusted to very low risk freeflow and a transfill whip so topping up a tank is a nonissue.

 

[CuzzA]

Good point about the predive switch. When I had an octo I never had a free flow, so I imagine older regs without that option create more issues with gas loss. The predive switch is also one of the contributing factors why I went ahead and elected to go with an AIR2 and necklaced pony. SP's 5th gen has a switch.

 

[2airishuman]

What reg are you wanting to use on your pony? My SP regs are super easy to convert. So were my Aqualungs (except the Calypso).

I bought a bunch of used Conshelf XIVs because they're cheap, abundant, bulletproof, and because I like the second stages. I thought the first stages would be OK for ponies and stages and intended to get DIN adapters and environmental seal kits for them. At this point I can't find either the DIN adapters or the environmental seals, so I'm trying to decide what to do with the first stages. Maybe I'll just sell them and buy another HOG D1.

I have a Conshelf XII which I have set up as a tire inflator.

 

[uncfnp]

Looks like you are in a similar situation as my Calypso's except at least the Conself is convertable but I don't think the service kits to do this are available. And I don't think the seconds have adjustment knobs for breathing effort either.

If this is what you have and they are serviced and ready to use, go ahead and set it up and choose for you whether to leave on or not. If you have a 19 cf or higher, just leave on. If smaller, consider the inline shutoff valve. Either should do well enough till you find a good deal in a first stage DIN.

 

[2airishuman]

I do use a 19.

No, the seconds don't have adjustment knobs, and the exhaust sticks out. I'm planning on using one of them as my primary, and moving the HOG classic I use for a primary now to the pony.

 

[dumpsterDiver]

DD, maybe you're right and I'm making this too hard. The idea at work here is that the closed tank valve is not only to protect against freeflow, it's a layer of protection against grabbing the wrong reg. Maybe with a slung pony that isn't much of a risk because due to the fact that the 2nd stage is bungeed to the cylinder, and that makes it pretty clear.

Who knows if I am right? But the issue with stage bottles full of oxygen or some other toxic at depth gas is a very very good reason to have the valve off. If you put air in the pony and it is a rec dive, the consequences of Mistaken ID are approaching zero and it would be really really hard to accidentally unbugi a second and not know it. Tech divers have a robust protocol to address multiple stage bottles.... You are driving to 7`11 not taking a rocket ship to Mars.

 

[Jim Lapenta]

The HOG D1 is not recommended as a pony or stage bottle 1st stage if there is any chance you are going to dive with the tank turned off at depth. Reason being is the turret O ring could allow water to intrude into the 1st stage if the reg is depressurized. If you want a pony reg the D2 is the 1st to use. The hose routing is good and there is no danger of water getting into the 1st. It does only come in DIN however.

 

[tbone1004]

what Jim said, d1=bad to turn off, same with the rest of the swivel turrets.

Yoke=bad to turn off for the reasons mentioned above. Increased risk of o-ring extrusion, increased risk of flooding the regulator, etc etc.

You can use yoke regs for now, it's not going to hurt anything, though long term I would certainly look at converting to din.
Balance Piston Din First Stage "For Pony / Stage Bottles!" "Nitrox Ready!"
I use these for my deco regs and they've been good to me so far, and are pretty cheap. Worth thinking about. If you are going to keep them pressurized, you can find the unsealed Hog D1 and BP2's for around $100 each which isn't bad.

 

[2airishuman]

what Jim said, d1=bad to turn off, same with the rest of the swivel turrets.

My engineering mind is having trouble with this. I've looked at the design HOG uses for the D1. There's nothing inherently directional about the turret seals. Turrets do not have a reputation for gas leaks. They keep air (and even helium, with a smaller molecule diameter) in. Why do they not keep water out? Why is the risk of water ingress any different for turrets than for other dynamic seals, particularly the SPG spool and the swivel where the 2nd stage attaches to its hose?

Balance Piston Din First Stage "For Pony / Stage Bottles!" "Nitrox Ready!"
I use these for my deco regs and they've been good to me so far, and are pretty cheap. Worth thinking about.

I've seen those, and I know Randy stands behind his stuff. I'm intrigued. How long have you had yours?