Can't reliably reach doubles valves....Help!

[Gareth]

This is one of those SB discussions that awes me. I've never found the need to touch my valve(s) once the reg is mounted. I turn them on all the way on, back off 1/4 turn and that's it! They don't get touched again until I take the reg off. Presently I'm using a tank mounted pony that I treat the same way. I can't reach my valves after 2 rotator ops. Some time this year I'll be using independent doubles which will be two single tanks banded together. Once them valves are on they'll stay on. I guess I don't get it all the valves and isolation and such. Two tanks two regs no muss no fuss throw the pony on and make it threesome. I want to dive not turn valves!

If you have a free flow caused by a first stage, your dive will get noticeably shorter unless you can either manipulate your valves or get someone else to do it. I guess it's something over here in freezing cold UK we get used to, but every now and again I jump off a boat and something needs shutting down rapidly.

 

[Blackwood]

Unless someone turns my valve(s) off, them babies are on full blast long before they get on my back

'cept that pesky quarter turn you mentioned...

 

[AfterDark]

'cept that pesky quarter turn you mentioned...

That's how you make sure it's on full blast, just like with any gas cylinder. That 1/4 turn doesn't affect the orifice one bit and leaves no strain on the stop.

 

[AfterDark]

If you have a free flow caused by a first stage, your dive will get noticeably shorter unless you can either manipulate your valves or get someone else to do it. I guess it's something over here in freezing cold UK we get used to, but every now and again I jump off a boat and something needs shutting down rapidly.

If you of my regs fails (free flow....) then if solo diving my dive is over and its time to turn around and leave. I'm now without redundant gas.

If my dive depended on all the gas I'm carrying then again time to go.

If diving with a buddy and I can complete the dive safely with the gas I have left I'll get him/her to shut it off.

We have cold water here in New England.

That about cover it?

 

[Gareth]

If you of my regs fails (free flow....) then if solo diving my dive is over and its time to turn around and leave. I'm now without redundant gas.

If my dive depended on all the gas I'm carrying then again time to go.

If diving with a buddy and I can complete the dive safely with the gas I have left I'll get him/her to shut it off.

We have cold water here in New England.

That about cover it?

Not really. I jump in first and my reg free flows. I shut it down, and open it again. It behaves itself. A few minutes later the rest of my team jump in and join me. We go diving. In your scenario the dive is canned as you are in the water alone and don't see the need to be able to reach your valves. I appreciate you cannot reach your valves due to a physical restriction, but its a bit silly to deny there's a need for doing so. I see regs freeflowing all the time here throughout the winter, and if we follow your argument of never needing to teach your own valves many of these people would just get out of the water. to paraphrase yourself, I want to be able to turn valves so that I can always go diving.

As an aside, most of the people I know that have rotator cuff injuries end up inverting their cylinders so that they can reach them.

 

[ianr33]

This is one of those SB discussions that awes me. I've never found the need to touch my valve(s) once the reg is mounted.

If you of my regs fails (free flow....) then if solo diving my dive is over and its time to turn around and leave. I'm now without redundant gas.

If you don't shut the freeflowing reg off you will very soon be without any gas at all,so why bother with the doubles at all?

They do look cool though.

 

[Sat Diver]

Please rig your tanks with the valves facing down.
This is the way I have always done it with manifolded doubles.
The other option is independent doubles.
If you have to have a manifold then try it this way. Do not use valve extenders.
They introduce an unnecessary additional failure point.

Ok, so I am a fairly inexperienced diver with only about 130 dives (although most have been in cold water and poor visibility or in relatively rough open ocean conditions.) I am experimenting with doubles (about a dozen dives so far) because I want to be able to do longer and or deeper dives that will require some decompression, and think that I should have proper instruction for such activities. I have “signed up” for some IANTD instruction which should occur in the near future.

However, I although I am trim, athletic, and have a low BMI, (and a low SAC rate) and have been a competitive athelete for most of my life I reach the point now in the year 2010 where I am 57 years old, have had rotator cuff surgery on my left shoulder, and simply no longer have the physical strength and flexibility that I once had. The net result is that I can sometimes reach the valves on my new doubles set, and sometimes not. I've read everything there is, including TS&M's reference to a complete instruction posting on reaching doubles.

I stretch my shoulders with weights while lying on the couch (to the hysteria of others in the vicinity). Nevertheless, it takes me an eternity to shut down a valve - if I can - (although interestingly the isolator is easier than the tank valves.) Common sense and a mechanical engineering background says to me that a set of valve shut downs that rest on my shoulder straps seems to be the “Only Common Sense” response. I am experienced in epoxy / carbon fibre / composite construction and can manufacture (or can buy if I know where-money, no object) some “valve extenders” that are extremely unlikely to fail. (Yes, at this point, I would rather stake my life on an extra layer of technology rather than the more uncertain and slower possibility of reaching the valves in a situation of regulator failure.)

However, before I move in that direction I have decided to seek out the feedback that ScubaBoard can offer, as I have found your input to be invaluable in the past. I am reluctant to rely too heavily on the redundancy of doubles until I solve this problem.

Thank you in advance for any input you might offer in regards to this issue.

 

[Akimbo]

Consider what commercial divers have been doing for 70+ years...

More like 40 years, which is when lightweight masks and hats began replacing deep sea gear on a large scale. Most of the rigs in JonKranhouse post were SCBA (not Underwater) used for firefighting and mine safety.

One of the biggest issues with mounting the tanks valve down is that it puts the valves where they are most likely to suffer impacts when tanks are moved around....

This is the big problem for recreational and technical divers use of valve-down rigs. The manifold and protector used on the Interspiro (and older AGA) Divator is brilliant. It solves four problems.

• Valve and regulator protection — valve up or down
• Ergonomic valve access (when worn valve-down)
• Provides a carrying handle that does not stress the manifold
• Allows relative movement between cylinders with minimal stress on the manifold

The last factor is the most amazing to me. One of the first lessons taught in high pressure tube fabrication is never use a straight spool (tube) between fixed or potentially flexing components. This is to prevent mechanical stress on the tube due to flexing, thermal expansion, and vibration. The normal procedure is to bend the tube to 90° or more or make a 180º pigtail.

Valve protection on surface-supplied bailout bottles is not an issue because there is a tender to help dress the diver and they sit on a bench in the middle of the deck that the tender can walk all the way around. Most bailouts are smaller and lighter than most recreational divers use, let alone tech divers. There is always a hook in the bell to store the bailout or are laid down on the deck on surface dives.

Commercial divers wear the bailout valve-down primarily for physical protection in the water rather than for reaching the valve. The tank valve is always turned on and a valve on the hat is used to switch to bailout gas. The clanging sound of the bailout impacting structure or when entering the bell hatch is common over the communication system.

The only valve protector I know of currently on the market for conventional rigs is made by Custom Divers in the UK, which I am not fond of due to entanglement concerns. I am playing with a protector for doubles with an isolation manifold now and will post photos if the prototype proves promising or I think useful mistakes can be learned from.

IMHO, it would be significant improvement if manufacturers would take the Divator concept and apply it to singles and doubles with isolation valves. Aside from being outrageous heavy and difficult to fill to 300 Bar/4,351 PSI, the Divator 324 is one of my all-time favorites to dive.

 

[Rich Keller]

The easiest thing to do is rig the tanks upside down. You may need some longer hoses but it is much easier doing it that way. I am 54 myself and even though the older I get the better I used to be that dose not help me reach it either.

 

[Sat Diver]

Bob,
This is infact the reason why I think inverting the tanks works better. I might be biased because that's the way I trained to rig bailouts, but it just makes more sense to me. The valves are more protected whilst diving, especially in cramped quarters.
Admittedly it is trickier getting the rig on and off without a tender, but someone can always play that role.

You mentioned wrecks ... do you go inside of them? If so, please consider that you can bang your valves on stuff in there (easily) ... and sometimes never know it. Because of the way your valves rotate, some possibilities present themselves ...

- You bang your right post and damage it. Now it's leaking ... maybe not catastrponically, but enough to be a concern. You decide to go ahead and breathe it down, then switch to your backup. But you need to be able to reach your isolator valve to close it, to prevent gas from your left cylinder from leaking out through the manifold and the damaged right post valve ... you're gonna need that gas once your right tank empties.

- You roll off your left post. It closes, and you don't even know it. No problem at all ... unless for some reason you need to pass your primary reg to a buddy. You pop your backup reg in your mouth, take a breath ... take another breath and halfway thru that second breath you're suddenly OOA. Now what? Your buddy has the other one. You can (if you're not in a restriction) get his attention and buddy breathe while he turns your left post back on. But if you're in a tight spot ... one of you is gonna be pretty well hosed, depending on who wins the battle for the working reg.

Of course, it's always possible that when you need it most, you'll discover that ... in fact ... you CAN reach your valves. Needing to breathe is a powerful motivator. But wouldn't it be nice to know beforehand that you could if you needed to?

... Bob (Grateful Diver)