Second stage exhaust check valve failed open, flooding the reg when breathing

[serpentara]

I suppose as an earlier poster stated, one could connect all of the second stages that are to be used on a dive with a quick disconnect fitting so if one fails you can simply play regulator roulette and swap them around. BOV Quick Disconnect Kit "Locking QD System" If guaranteed second stage functionality was necessary for a dive, that should in theory work

In my case I could not easily swap out the the whole first and second stage. All that I had were my twins HP100s and deco bottle. I did not have travel gas. So, while hanging from a SMB at 20 feet I would have had to take off my doubles, try to unscrew the first and second stage, and attach it to the deco bottle. That seems like a recipe for disaster. I cant imagine trying to make sure that everything is neutrally buoyant.

My deco instructor happened to be on the dive with me (he was doing a surface interval on the boat from an earlier deco dive) and I asked at what point they would put another diver in the water. He said that my deco time was "longer than he thought it should have been" and said that when they do really deep dives, the signal for needing help underwater is to send two SMBs up the same line. If they see two SMBs they know something bad has happened and they send another diver into the water with gas. So I will be buying a second SMB in a different color.

 

[uwxplorer]

It would be interesting to see your dive profile and know your GF. Maybe you would have been fine cutting your deco short by a good deal?
Some divers have a minimum minimorum bailout plan (say GF100/100) just in case...

 

[Michael Guerrero]

If I was looking at 40 extra min of deco to do it on air I would have done what AJ said in post #22. So maybe another SMB and a small crescent wrench you can keep in a pocket.

 

[Dr. Lecter]

Ugh, nevermind.

---------- Post added October 29th, 2014 at 11:12 PM ----------

I feel like you're really telling me to bring my torque wrench diving because it's good to have them "correctly" torqued, which just having a tiny wrench wouldn't accomplish due to being able to still under/over torque them without the torque wrench. But honestly, I've never seen anyone at a dive shop use a torque wrench to apply the "correct" torque. I've just seen some people crank on them a little, and some a lot.

No, I'm not. I'm telling you that hand-tight is way too ing loose for that purpose. If you want to be able to swap stages among regs, bring a wrench. Don't fail to tighten your hose connections sufficiently.

And really, I think the principle is the same whether you're talking about 1st or 2nd stages. You can remove either one under water from one tank to another if necessary and if you think it's prudent. And I think this should be something discussed with divers because it doesn't always occur to people that it's an option. However, to say that this thread is only talking about first stages is kind of splitting hairs. Especially since the issue originally described was with a second stage.

Yeah, no. The general principle is that you can pull a whole reg off one valve to get at the gas in a different bottle with a non-functional reg if need be. If you want to play musical stages underwater with a wrench, I suppose that's cool too. But unscrewing a couple DIN fittings and reattaching one is going to be a lot easier than trying to use a wrench to move hoses and stages around on flooded regs until you thing you maybe got it right...less chance of slicing a tiny o-ring in the process, too.

---------- Post added October 29th, 2014 at 11:14 PM ----------

Dr. Lecter,

That's a very interesting statement. You obviously are talking about DIN fittings, as the US yolk fitting (A-Clamp) has a hand screw on it. I have not heard of torquing a DIN fitting or a yolk fitting since we went away from the flat teflon washers on valves (early 1950s). To my way of thinking, from the engineering side, if a torque wrench was needed, the DIN fittings would not have a round knurled ring for hand-tightening the fitting against the sealing surface. The DIN fitting requiring a torque wrench would have a flat surface for the wrench to seat upon. I have never used a torque wrench to tighten my regulator first stage connection to a valve, and have never had any problems with it either. However, as you stated, wrenching the second stage regulator hose is a requirement.

I just wanted to clarify the statement that it is not the first stage connection to the valve we're talking about, but the hose fittings connecting the first and second stages of the regulator, and the other regulator hose fittings.

Michael,

I agree with you about the Rouse's, that there were many, many breaks in protocol. However I think it was the submarine U-Boat the U-WHO. I used it as it was the only example I had of a malfunctioning second stage where the person inhaled water. I actually had one mouthpiece split, but never got water through it.

SeaRat

I am now terribly sorry I did not just say "sufficiently torqued". Le sigh.

 

[The Chairman]

There are two ways in which an o-ring seals. One, such as the static seal on your yoke or DIN first stage to the tank, requires sufficient torque to create/maintain the seal. The other is the dynamic seal found on the second stage to hose interface. Here, the tube within a tube sealed by an o-ring does not require a specific amount of torque to work properly.

One has to ask then, why it's OK for the yoke or DIN seal, that relies on sufficient torque to be hand tightened, but not the one that does not rely on torque at all? Phobia? Perhaps. Ignorance? Quite probable. Safety? Not a bit. Maybe an illusion of safety, but that only gets back to ignorance.

If you don't examine your hoses and fittings on every dive, then you should probably wrench that thing down until the threads start to give. However, if you're reasonably proactive in this regard then what's the big diff? The o-ring will not leak until the hose is over a 1/4" unscrewed. That's a lot and should be noticed in even a cursory inspection. No, it's not likely to be dragged across ceilings where it could be rolled off suring the dive, so what's the big deal? I wish I could say that I have never had a first stage go whacko. It happens. When it does, I like to keep my options open and that means having my second stage regs only finger tight. Yes, I have had a leak on the second stage o=ring. Shutting off the valve, undoing and then reattaching the second stage is a simple fix. Odds are, if you simply tighten it, you'll wreck the o-ring.

Just a note about hoses. The hose to first stage o-ring IS a static o-ring. Please tighten accordingly with the proper tool.

Another note, but this time about regulators. If you don't understand how your regulator works, take a HOG class. Even if you don't dive a HOG, you'll come away with a better understanding of the feedback mechanisms in your regulator.

 

[Michael Guerrero]

And buy Pete Wolfinger's book "Scuba Regulator Savvy".

 

[clownfishsydney]

Depending on your reg, it may be easy to fix or impossible. I have had this happen a few times, easily fixed underwater with my regs. A long purge may push it back into place.