Better alternative to 3cf spare air?

[JamesBon92007]

It sounds to me like somebody is not looking at their SPG anyway which makes me think: J-Valve. With an AL80 the 300 psi reserve from the J-Valve will get you, according to what I figured, about 7.75 cu/ft.

 

[bergersau]

EDIT: I just stumbled across this h2odyssey air source 3 thing (on a 6cf) which appears to be someones attempt to come up with exactly what I am looking for, anyone know anything about it?

If you go with this design make sure you check the swivel screw is secure every dive as part of your standard pre-dive checks. I know several people with h2odyssey style 6cf cylinders (Unsure if same brand). One had his reg swivel fall apart under water losing the second stage completely, another found his swivel screw was loose and was able to fix the issue before it fell apart mid dive.

I personally opted for a slung 19cf instead of a h2odyssey style 6cf bottle and do not regret that choice at all. It's only marginally larger in diameter, the extra 6 inches or so of length don't bother me underwater and it is less negatively buoyant when full as compared to a 6cf cylinder.

time to get to me and communicate her need if we aren't right in front of each other when something happens.

That's an interesting point that I've though of myself but haven't seen in conversation here before. Everyone immediately starts talking about how much gas is needed for a slow controlled ascent and safety stop. The idea of a small 3-6cf pony to give you time to reach a distracted or somewhat distant buddy and start an air share on their main cylinder never seems to come up for some reason. It is not my preferred option but I can see a place for it for some people.

 

[uncfnp]

hat's an interesting point that I've though of myself but haven't seen in conversation here before. Everyone immediately starts talking about how much gas is needed for a slow controlled ascent and safety stop. The idea of a small 3-6cf pony to give you time to reach a distracted or somewhat distant buddy and start an air share on their main cylinder never seems to come up for some reason. It is not my preferred option but I can see a place for it for some people.

It's been mentioned before by others also trying to justify a Spare Air but there are several factors to consider, especially if buying a 3 cf specifically for this purpose.

First and foremost, swimming after an inattentive or distracted buddy brings you no closer to your ultimate goal, the surface.

Dive conditions as well as the distance to your buddy maybe unpredictable. Too far away? Poor viz? Up current? Swimming against current at depth will use up 3 cf pretty darn quick so what next?

So yes, under a very narrow set of circumstances the Spare Air could be used to swim to a buddy and something to keep in mind but I certainly would not buy one with this as my plan of action.

And if going to go to all the trouble to buy and carry redundancy I personally can only see one reason to limit my OOA/LOA options to a Spare Air and that would be if it was the only viable option, such as with the limitations imposed by the op's buddy or limitations that can be created by dive destination travel. In these cases it is indeed better than nothing.

 

[Kharon]

LP port, right?

Yes - the H2Odyssey has HP and LP ports just like any 1st stage.

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.

Not sure why I would ever want to remove the reg on my pony and move it to another tank. If I did, I could just unscrew it from the LP port and move it to another 1st stage. Exactly the same if you were moving it from one 1st stage to another. It is easily done - I just don't see the point. Methinks you are grasping straws in order to argue against ...

 

[Ojai Diver]

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.

It's easy.

If the tank is empty, no tools are required. Also, if you want a bigger bottle, you can simply screw one on.

 

[John Mooradian]

Been diving for a while but only recently decided to get certified and buy a full kit. I dive both cold fresh water (dry suit) and warm salt water. (Wet suit, as appropriate). I do a fair number of dives alone. Nothing deep. Generally 20 - 40 feet in the cold fresh water. Whether alone or with a buddy / group I like to be self sufficient. If I can help someone else it's good, but I must be able to help myself. My thinking - right or wrong for others - is that my redundant air source needs to be substantial enough that I have time to resolve whatever problem I / my buddy may have. I would not feel confident with a 3/6 cf supply as a back up. I dive the set up below. I practice it often. When I travel I take the regs / gauge and the rigging and grab a tank from the dive op. Getting a 40 can be tough, but the rigging accommodates an 80 also. You get some funny looks sometimes but I'm OK with that. In my dry suit I slide my tank band weights to right side and sling the stage bottle on the left. Easy to stay in trim. In wet suit it's a 5lb. in the right pocket on my harness. Again. Simple. (BP and Wing set up). Under water you don't know it's there - and there is lots of air if I need it.

 

[2airishuman]

Yes - the H2Odyssey has HP and LP ports just like any 1st stage.



Not sure why I would ever want to remove the reg on my pony and move it to another tank. If I did, I could just unscrew it from the LP port and move it to another 1st stage. Exactly the same if you were moving it from one 1st stage to another. It is easily done - I just don't see the point. Methinks you are grasping straws in order to argue against ...

No, it's like this. I have 4 pony bottles, 11, 19, 40, and 40 cf. Each one has a DIN valve. I have a pony regulator set made up of a (DIN) 1st stage, 2nd stage, and button SPG. I can and do take more than one pony bottle with me while shore diving. For example, I can practice deploying and using the pony on one dive, and then switch to a full bottle and have it ready to use for another dive. Or, I can use one of the bottles as a stage, that is, as an integral part of the gas plan rather than for emergency use only, then switch to a full bottle for the next dive.

If I did this with integral first stages the way you suggest, I would have two choices. One would be to purchase and maintain a separate 1st stage and SPG for each bottle, at considerable added expense. The other would be to drain the bottles of air to remove the 1st stage and move it to another bottle, which would then have to be filled. This is inconvenient for me because larger bottles cannot be filled reasonably full in a single transfilling operation and because the donor cylinder then has less air in it than I would like to have for a dive. I often dive where there is no LDS within reasonable driving distances and have to bring all the gas I plan to use for the trip.

 

[Kharon]

... For example, I can practice deploying and using the pony on one dive, and then switch to a full bottle and have it ready to use for another dive. Or, I can use one of the bottles as a stage, that is, as an integral part of the gas plan rather than for emergency use only, then switch to a full bottle for the next dive.

If I did this with integral first stages the way you suggest, I would have two choices. One would be to purchase and maintain a separate 1st stage and SPG for each bottle, at considerable added expense. The other would be to drain the bottles of air to remove the 1st stage and move it to another bottle, which would then have to be filled. ..

Once again you miss the obvious to push your argument. You don't have to drain the bottle. You just have to shut the valve and then remove the SPG and 2nd stage and install it on the other H2Odyssey.

Also, your dive parameters are far different than the OP is asking about - and I would suggest, different than most rec divers that simply want an independant air source as a safety backup. Those divers will have a single pony rigged the way that works for them and that's the way it will stay.