Better alternative to 3cf spare air?

[Marie13]

My opinion on ponies mounted on main tanks is that they are a PITA on the small six pack boats I've been diving on. Yesterday, a guy with a back mounted pony decided to take up nearly all the room on the small two person bench we were on behind the captain. Refused to move his second tank onto the floor so I could put both mine up. I got my revenge by asking him to move my tanks around for 2nd dive.

Sling the pony, unless you have a BC that doesn't allow it, in which case, be mindful of the space you take up when boat diving.

 

[TMHeimer]

I mount my 13CF pony the very rare times I use it (on deep dives). Yes, it is a pain moving it from tank to tank on a boat, but once it's on there I think it's better than slinging. I used to sling a 19CF one. There are plusses and minuses to both.

 

[RyanT]

Add - skip the "equipment solution to a skills problem" bushwah as well. Having an independant air source is just sensible and best practice - even in a good buddy team. If it was not useful SDI would not make an independant air source a requirement for solo diving in their Solo Divers Course and recommend a pony over other methods.

I don't doubt the usefulness of a redundant air source. The OP indicated, however, that his wife was reluctant to carry a solid redundant air source. And when I say "solid" I mean something other than a spare air. Of course they have a ridiculously small volume. In addition, the combination 1st/2nd stage on the spare air entails design compromises and, in my experience, makes them prone to leaking. I have not used the 6 cf redundant systems, but in addition to the increased volume of gas, relative to the spar air, the separate 1st/2nd stages almost certainly are better.

Regardless, back to my original point, if the OP's wife is relucant to carry a good solid redundant system, then the real solution is better buddy skills.

 

[Kharon]

The drawback of the valve-integrated 1st stages is that you can't remove the regulator, whether for ease of transportation and storage, or troubleshooting, or to move it to another cylinder.

Nonsense. THe H2Odyssey can be removed and is completely disassembled for service. It can be removed from the bottle for transport, installed on any tank, the 2nd stage can be removed and replaced with a hose and octo, etc., etc., etc. You obviously know not of which you speak.

 

[Kharon]

The H2Odessy 6 cf system appears to cost $330. It does not use a hose between 1st and 2nd stage, has a direct connection, more like a SpareAir
View attachment 424240

It is simple to remove the 2nd stage and add a hose between the 1st stage HP port and the 2nd stage if you want. I have both setups. One with hose and one without.

 

[scubadada]

It is simple to remove the 2nd stage and add a hose between the 1st stage HP port and the 2nd stage if you want. I have both setups. One with hose and one without.

LP port, right?

 

[Saboteur]

Let's start with what a spare air is.

The current production ones are:a 1.5cf or 3cf aluminum 3000 PSI cylinder, with a nonstandard smaller neck thread, equipped with an integrated regulator that combines: valve, 1st stage, 2nd stage. Refill is via an adapter.

For larger, you can get the h2odyssey. Same idea, but a standard neck thread and separate 2nd stage that doesn't use a hose -- it's attached directly to the 1st stage using a swivel. Cylinder sizes vary.

You can roll your own, as it were, using valve-integrated 1st stages. Piranha has these for sale online as do various other retailers. You can add a 2nd stage using either a swivel or a hose, and again, refill is via an adapter.

You can also get transfill whips that will allow you to transfer air between two cylinders with standard yoke or DIN valves.

The drawback of the valve-integrated 1st stages is that you can't remove the regulator, whether for ease of transportation and storage, or troubleshooting, or to move it to another cylinder.

The Zeagle Razor system can be removed from the tank. It can be removed with a crescent wrench or you can use a first stage vise handle (available from Scubatools.com). This information csme from Zeagle. If you are on a vacation I don't know how easy it to do though. I am considering either the Zeagle or the H2Odyssey.

Let's start with what a spare air is.

The current production ones are:a 1.5cf or 3cf aluminum 3000 PSI cylinder, with a nonstandard smaller neck thread, equipped with an integrated regulator that combines: valve, 1st stage, 2nd stage. Refill is via an adapter.

For larger, you can get the h2odyssey. Same idea, but a standard neck thread and separate 2nd stage that doesn't use a hose -- it's attached directly to the 1st stage using a swivel. Cylinder sizes vary.

You can roll your own, as it were, using valve-integrated 1st stages. Piranha has these for sale online as do various other retailers. You can add a 2nd stage using either a swivel or a hose, and again, refill is via an adapter.

You can also get transfill whips that will allow you to transfer air between two cylinders with standard yoke or DIN valves.

The drawback of the valve-integrated 1st stages is that you can't remove the regulator, whether for ease of transportation and storage, or troubleshooting, or to move it to another cylinder.

The Zeagle Razor system can be removed from the tank. It can be removed with a crescent wrench or you can use a first stage vise handle (available from Scubatools.com). This information came from Zeagle. If you are on a vacation I don't know how easy it would be to do though. Most rooms don't have a vise. Maybe its easy if you have Popeye arms. I'm interested in the Zeagle system. If anyone knows how easy/ difficult it is I'd like to know.

 

[2airishuman]

Nonsense. THe H2Odyssey can be removed and is completely disassembled for service. It can be removed from the bottle for transport, installed on any tank, the 2nd stage can be removed and replaced with a hose and octo, etc., etc., etc. You obviously know not of which you speak.

Perhaps I could have been more clear. You can remove it from a cylinder in the same sense that you can remove a valve from a cylinder. The cylinder has to be drained, and you may need a wrench. If you install it on a different cylinder, that cylinder has to be drained, too, and the valve removed.

In contrast I can take my stage regulator off my AL19, store them separately, reassemble them and use them, repeat, switch to another size cylinder if needed, etc.

 

[PatW]

How much air does your wife use for an ascent from depth and also for a safety stop? Knowing this will give you a ball park figure for the minimum amount needed for a bail out bottle.

In my case, I am referring to the aluminum 80 as a reference. I can do a safety stop with air to spare on 100 lbs pressure. At a 3000 fill, that comes out to 80/30 or 3 cf rounded up. I am not sure how much I use in an ascent, but I think it is about the same as a safety stop or again 3 cf.. So a spare air should get you to the surface, but you have to ditch the safety stop. With 6 cf, you probably have enough for ascent and safety stop. If you discard the safety stop, you should have air to spare for the ascent.

The above is assuming that your wife can do a safety stop and an ascent on 100 lbs each. I would not feel comfortable without testing that under actual conditions.

I think the 6 cf bottle with hose and regulator might be an adequate option. I like the hose and regulator because it is similar to your normal equipment. In an emergency, I would think you want everything as normal as possible.

 

[scubadada]

Actually, the best way to estimate needed pony size is to use your RMV and do the ascent calculation. Using twice your average RMV and including a minute at depth, a normal ascent and a safety stop, makes for a conservative calculation.

As an example, for me, I would need a little over 8 cf to do this from 60 ft. I could easily argue that I would not need the minute at depth, my RMV would not be twice average, or I could skip the safety stop on a no-stop dive. This would allow me to get away with a 6 cf pony.

In reality, I sling a 19 cf pony. That would generally allow me a safe ascent from recreational depths, consistent with the above conservative assumptions.