A Case for Spare Air

[BRT]

Almost always yes. But I count a willing and able buddy as redundant source. Of course it works both ways for my buddy.

I’m trying to think when I don’t have a redundant source: very shallow dive (~10 feet) for a short dive. Rare.

Good on you. You carry a pony to travel?

 

[caruso]

Does the SA system come with a trans fill whip? Or, is that an optional item? If a diver has the trans fill option, they can test the SA all day long, right?

The Spare Air I used to dive with came with it's own proprietary refill adapter, simply screw it onto any available tank and fill the SA as often as you like, but obviously you need to consider that you'll have that much less air in the tank you're pulling it from.

 

[ReefHound]

Hi EFX,

Does the SA system come with a trans fill whip? Or, is that an optional item? If a diver has the trans fill option, they can test the SA all day long, right?

I don't know how one would fill an SA. I would like to know the options.

cheers,
m

There's an adapter that connects to a port on the SA and a yoke. Does anyone make a compact transfill for a pony? Something that would look something like this except two yokes connected directly.

 

[ReefHound]

Now obviously, with their adapter refill you need a tank with more than 3000psi if you want a SA 3000psi fill. In reality, a user will often end up with a bit less, maybe costing a breath or two.

 

[caruso]

^^Good point @ReefHound I never really thought of that, and looking back to when I had my Spare Air I recall filling it on occasion off of a partially used tank so as not to drain a full one. Oops.

 

[wetb4igetinthewater]

Everyone chooses their level of risk, you would need a couple of Spare Airs to get 6 cuft.

There is a cu ft version for $380 now.

I've made a number of CESAs, and on another occasion, dropped a 30# weight belt and I never shot out of the water like a Polaris missile. Closest I came was buoyant ascent training in sub school, but the concept was to ascend from depth as fast as possible.

Polaris missile was a bit of poetic license. It came from the attached spreadsheet where i compared different redundant gas sources where the user can specify RMV and stress factor.

Just curious. When you performed CESAs, were you actually out of air?

And even when when it isn't maintained, from my experience.

I did say it was extremely rare. That would imply that it does happen. Just not often.

 

[EFX]

Does anyone make a compact transfill for a pony? Something that would look something like this except two yokes connected directly.
View attachment 512309

I don't know if anyone makes a compact transfill. Would that work? Can you get two tanks that close together? I bought a whip for $200 that has a yoke on both ends of a 4 ft high pressure hose. One end has a gauge and you can screw part of the yoke off to fill a DIN valve tank. Real handy for equalizing the pressure between tanks.

 

[ReefHound]

I don't know if anyone makes a compact transfill. Would that work? Can you get two tanks that close together? I bought a whip for $200 that has a yoke on both ends of a 4 ft high pressure hose. One end has a gauge and you can screw part of the yoke off to fill a DIN valve tank. Real handy for equalizing the pressure between tanks.

Lay the tanks on the ground at 180 degrees, valve to valve, bottoms facing away.

Yeah, I have a whip just like that. It's a bit heavy though, wouldn't want to lug it along with the pony rig on the plane. I suppose I could get another one and modify it, remove the spg and one of the purge valves, and replace the hose with a 6" miflex. I wouldn't have to take it to every location so long as I can guarantee pony fills at the destination but sometimes that isn't possible without a hassle.

Btw, I sling a 19cf pony when I solo dive in Flower Gardens. My defense of SA is only that it can be useful in certain applications, since so many just blindly villify it without question. I've been borrowing a buddy's SA when I'm on working dives to tie in sideline, set strobes, or run sight line. Those are 10-15 min max with no safety stop. That buddy is no longer working on the boat so this season I'll be slinging the pony unless I opt for the lighter alternative. I'll probably get a 6cf bottle since I have plenty of spare regs and spg's.

 

[ReefHound]

I did find this compact turn-key 6cf pony bottle solution by Zeagle but it's pricy. Note the special transfill adapter.
6 cu ft Pony Bottle

 

[markmud]

Now obviously, with their adapter refill you need a tank with more than 3000psi if you want a SA 3000psi fill.

I use the tank for my second dive to initially fill my 6cf pony and then use the tank for my first dive to top it off. I am not a gas hog (.5cf working SAC, not resting RMV). So that works fine. Mostly, I get a shore dive tank before we dive for the initial fill-up.

One end has a gauge and you can screw part of the yoke off to fill a DIN valve tank.

Yeah, that's what I have.

My defense of SA is only that it can be useful in certain applications, since so many just blindly villify it without question.

I completely agree. I have been run-through over my 6cf pony. Even my SOB wife gives me the verbal shiv over it. For a person, or a situation, where the dive is less than 60 ft, and the diver is not conditioned to "freak-out" when the SHTF, a 3cf SA is an OK solution.
I don't recommend the 3cf as it is too limiting. I would suggest the 6cf if one must buy SA, or get a pony bottle with regulator--after all, it is cheaper.

An SA in your luggage is better than the 19cf, 30cf, or 40cf, that stays in your garage while you travel the world.

cheers,
mm