Is H valve a good replacement for the pony?

With the exception of OOA scenario, is H valve a good replacement for the pony bottle for recreational divers?

No.

A H Valve really doesn't have much use at all. (mind you, neither does a pony.)

No. "H" valves fail at the joint too often to be considered safe. Pony bottles, if large enough to be effective, are a better choice. "Y" valves are a better choice than "H" valves, but can be hard to find. Doubles are usually the best choice if you're in a situation where truly redundant air supplies are needed.

allenwrench:

With the exception of OOA scenario, is H valve a good replacement for the pony bottle for recreational divers?

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A quality H-valve such as a Dive Rite or Thermo has little greater potential of failure than any than other options such as a K or J valve or doubles manifold. All dive eqpt. has failure points. They have offered another option to divers on single back gas tanks for years with success. You might be able to source some Y-valves from the UK at a premium price.

The use of an H-valve does offer some redundancy in that you now have 2 first stages that can be used....in the event of the primary first stage failing.

A pony bottle is a good option for single tank divers diving NDL profiles.....they are a true contingency source of gas for the singles diver and I would recommend them.

Before I switched to diving only doubles (which are the best set-up), I dove a large steel single tank with an H-valve and slung a pony bottle....that combo provides a respectable level of protection for recreational diving.

Yes,

For me it does,not in a OOG situation,but when a reg.fails I can shut off the failing reg.and switch to the other one.
Is it a perfect solution Guess not,there's alway a better way.That said,it served me well.
Had some unwanted freeflow's,just shut the perp.down and switched to the backup reg.
And of dive,YES.
Problem,NO.

NEVER had a OOG in real life,besides in the pool.Still don't understand WHY someone would ever get OOG on a "normal"dive.If you know your SAC,watch your gauges,how can you get OOG.

just my 0.02cts

texdiveguy:

A quality H-valve such as a Dive Rite or Thermo has little greater potential of failure than any than other options such as a K or J valve or doubles manifold.

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Not to put too fine a point on it but "Phooey."

Without careful handling and monitoring, the joint between the "H" attachment and the modular valve doesn't represent a potential failure point, it's routine failure point. Torque limits on brass are serious business and the jam nut isn't always enough to hold everything together. Unlike a manifold attachment, the H attachment doesn't have any built in limit to how far it can spin once it gets started. It doesn't take much of a whack to loosen the thread tension, once that happens an H valve is going to fail. Since the K, Y and the antiquated and outdated J valves don't have the modular connection, there is no issue with them failing at that point.

People are going inside wrecks and caves with H valves thinking they're safe because the H valve offers them a redundant first stage. In reality, they've added a valve that is prone to failure when they bang into something.

Though I won't use them anywhere, H valves make some sense in cold water, where valve failure is less of an issue than first stage freeze-ups. They still need to be handled carefully and monitored closely.


Thermo DIN/K H Valve. Fail to monitor the jam nut closely or bang into something (or have something bang into you) and the assembly can start to unscrew, resulting in (a) a leak, and; (b) more excitement than most people want to deal with.


Thermo DIN/K Manifold for doubles. Best solution! Unlike an H, the manifold is held in place by the opposing modular valves. Even if the manifold starts to spin, it's kept from spinning too far.


Sherwood yoke Y - knobs are too small, poorly positioned, yoke only connection.


Beuchat DIN/K Y - bigger knobs, better position, accepts DIN or Y connections.

reefraff..........

As with all of our dive gear we of course need to maintain and monitor it for proper care....goes without saying....no big news there.

I have not seen a diver have a H-valve fail yet. I have seen and had tank to valve o-rings fail....normally the fault of an improper installation.

Not sure how many divers are out there doing wreck penetration or cave dives with H-valves....my guess is VERY few! Many users of H-valves are o/w divers, and yes they are quite common in cold water and ice diving environments.

To blanket state that H-valves are prone to failure is just wrong, as they are not. They may not be a piece of equipment you favor, but they are an option worthy of consideration for singles divers just as is the use of pony bottles.

Nice set of photos you provided........any guess as to the current cost of a Beuchat DIN/Y valve...........

texdiveguy:

Many users of H-valves are o/w divers, and yes they are quite common in cold water and ice diving environments.

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Not really an H-valve, but I like my set-up for cold water diving...

I don't think H-valves are that unreliable either. If they were, they wouldn't be allowed at the Intro Cave level and we have yet to have a fatality of a Intro Cave diver wearing a single tank (that I'm aware of).

There are a few disadvantages, one being that you will have difficulty renting H-valve tanks from any random dive shop but your regs will be set up specifically for using one. That can cause logistical problems in some situations--just try doing a 2-tank dive day with a K valve on one tank and a H valve on the other. Also, in order to be of any benefit you have to be able to do a valve shutoff quickly in the event of a problem.

I used to be all for H valves and didn't like pony bottles, but after rebreather training with bailouts I'm starting to see the advantages of a pony (which is really just OC bailout for OC equipment): no one gas failure can possibly jeopardize your life and require immediate action, no reliance on a buddy is required, and you can assist other divers by handing off a slung pony to them instead of being tethered with a hose air-sharing. Most of these advantages really don't come in to play in true recreational diving, though, and there are a few skills that are good to know concerning stage bottles to really take advantage of all this.

If you have H or Y valve you need to make sure your shutdowns are VERY fast - you only have 1 tank and it will empty quickly (especially if a problem happens at worse point of dive - just prior to ascent). If the shutdown is slow you'll lose too much gas.

My advice - get a completely redundant air source (so pony or twinset)