So who’s ever brought up their second stage in a lobster bag?

[MichaelMc]

My second has popped off for being loose, though thankfully on the pool deck when I'd gotten out to reconfigure my firsts and hadn't touched the second... ops. (A workshop with my (tiny) sidemount, not my tiny doubles..., non the pony on my disused gear shelf.)

A question for our regulator experts, @rsingler, @couv:
Would screwing it back together underwater and carrying on force water into the balance chamber and be a short or long term concern? The air in the balance chamber is now at ambient. The orifice is now filled with water. You hook a pressure hose to it that drives the balance chamber back to +145 psi. The only thing between was (salt) water in the oriface, Until the 2nd stage valve opens. So... Seems like water goes into the balance chamber. Water still transmits pressure, so it seems it would still work..? But that (salt) water seems like it will be trapped in there, any that gets all the way in, eventually corroding things. Does playing with that warrant a rebuild? If it's an issue, would depressing the diaphragm while pressurizing help?

An unbalanced (109) seems like it wouldn't care, as the only place for the water to go is out.

 

[doctormike]

OW scuba gear is designed simply and reliable. Maintain it, ensure that any repairs or modifications are correct before getting in the water and odds of a failure are extremely low. Forgetting to tighten a second stage is the opposite of that.

Are you saying that redundancy is unnecessary for OC divers? The captains of pretty much every dive boat in our area require a redundant gas supply, even for recreational dives. That means doubles, or a pony bottle for single tank divers.

Rebreathers are a separate issue. The rebreather accidents I've read about have been due to user error.

Exactly, because the redundancy addresses a lot of the risks related to gear issues. What is left is more likely user error.

 

[doctormike]

Anyway, I have an H-valve on an HP-120. Probably sell it, doesn't get out much. What it DOES do is keep things simple when switching from singles to doubles. But it doesn't provide redundancy on what I really want, which is something to breathe.

A properly sized and mounted pony is the slickest thing out there. I can drop everything in a hot rush and grab my pony as the very last horse out of Dodge.

Exactly.

 

[uncfnp]

@Angelo Farina your hand tight is likely a bit more snug then mine.

FWIW I am SM trained and did explore that option for recreational but it just was not practical for my dives.

@MaxBottomtime we well know your mind set on pony bottles. But I am human and as such fallible. I don’t know that I didn’t tighten that connection but it is the most logical explanation. Denying the possibility of human error or equipment failure and so not planning accordingly is like the ostrich with his head in the sand.

 

[MaxBottomtime]

Are you saying that redundancy is unnecessary for OC divers? The captains of pretty much every dive boat in our area require a redundant gas supply, even for recreational dives. That means doubles, or a pony bottle for single tank divers.

I can't imagine living in a society such as that. Fortunately, everywhere I have ever dived I have the freedom to dive any configuration I wish. It is extremely rare to see a pony bottle on a West Coast dive boat. Of the 100+ divers I have dived with over the last 30 years, two own ponies.

 

[rsingler]

Would screwing it back together underwater and carrying on force water into the balance chamber and be a short or long term concern?

That's a really perceptive question! If we look at the diagram below , what we're talking about is a jet of water being forced in the direction of the yellow arrow on the right.

As you pointed out, when the hose becomes disconnected, the balance chamber (in red) is now at ambient. Of course, it was at ambient plus IP before it became disconnected. So when the reg is re-pressurized, that blind chamber is going to have something forced down the channel. Given the squirt of water that's in the new connection between the hose and the orifice, there might indeed be a tiny bit of water that goes down the channel, along with the air. But as a blind channel, it will resist accepting any more than a drop of water. Most will hook left and go past the seat and out the barrel.
However, there's likely still a bubble deep in the balance chamber that will maintain the reg's responsiveness.
As for corrosion, both the poppet and the balanced chamber are plastic, so seawater sitting there, even for a long time, shouldn't make a difference. I wouldn't tear down a second stage that's been disconnected underwater. I probably would likely just give it a lot of purging after the dive and a freshwater soak.
When it is serviced, the reg tech may find a drop of water in the balance chamber. But as long as any bubble at all persists in the poppet channel and the red balance chamber, the reg's performance shouldn't suffer.

Good question!

 

[Couv]

The orifice is filled with water. You hook a pressure hose to it that drives the balance chamber back to +145 psi. The only thing between was (salt) water in the oriface. So... Seems like water goes into the balance chamber.

You have a clear understanding of how that balancing system works!

I'm no expert, but here is what I think. Remember, the balance chamber and poppet would still have air in them, so after compressing some of the air when a demand is made it is probable the air pushes out the liquid in the gap between the soft seat and orifice.

Water still transmits pressure, so it seems it would still work..?

....Yes.

But that (salt) water seems like it will be trapped in there, eventually corroding things.

If water entered the balance chamber it may get trapped-but all of the path from the soft seat-through the poppet-and the balance chamber itself are all made of plastic so no corrosion. Salt crystals may form and cause blockage or degradation of of the balance chamber/poppet o-rings. Therefore, yes. I would do a clean and rebuild-but not worry about it until I returned from a trip. Even a long trip.

An unbalanced (109) seems like it wouldn't care, an the only place for the water to go is out.

Correct.

Edit: Dr. Rob was quick on the draw. Why do I bother? I guess Miss Bush, my typing teacher in high school, should have given me a failing grade.

 

[Schwob]

Just can't help myself with that stupid comment:

No lobsters in the bag.

So, you really brought your 1st stage up in a regulator bag then...

Thanks for posting as it is a good illustration to learn from and I am very glad it turned out such that it is also good for a chuckle.

 

[rsingler]

Hey, @couv ! At least we agree!
'Course, you're more religious about this than I. You'd get the reg torn down. But at least you'd wait til the else of the trip.

Wasn't typing class awful?
I waited to start pecking. Honest! I looked for you, 'cause I knew you were online. You gave a more comprehensive reply. That's why you finished later. But your answer is better. You serviced the reg after the dunk. Better answer.

 

[barth]

Yes, an H-valve, or, better, an Y-valve providing no O-ring or other point of failure and two independent air paths (with two separate dip pipes).
A compact double is also very good, provided that the manifold allows for separating the tanks by means of a third valve.
But this setup, albeit very practical, has more possible points of failures than a single with an Y-valve. Considering the benefits and the drawbacks, I evaluate that both solutions are substantially the same in terms of safety. What I consider truly unsafe, even for very shallow depth, is a single with just one valve and an octopus. As in all places were I did dive all singles were always equipped with twin valves, why the hell people insist using an octopus instead of two separate regs? Just for saving money, or weight???
And why do instructors teach students using an octopus, when we should teach that it is a less-than-safe solution?

I don’t think adding more equipment is the solution for all problems.

if you’re diving with an y-valve and loosing one second stage, do you think that would be better in this situation?

You’re loosing a lot of gas. Now you should identity the failure and choose the right valve to close. If you close the wrong valve it’s really a bad situation. It will take some time to identity the failure and close the valve. In that time you’re still loosing gas.

(If one valve is closed and you’re loosing buoyancy and become negative and the valve with your bcd hose is closed and you can’t manage the situation that would also be a bad situation.)

I think it would be better for a rec diver when there is a failure (signal it to your buddy) and go to directly the surface. Don’t waste time and gas by identify the failure and try to solve it.

For tech or cavediving it would be different. Going directly to the surface is not an option. You should identity the failure and (try to) solve the problem. But for this type of diving I want redundancy. I think a single tank with a y-valve is not enough for this type of diving. I would use doubles. REC training is also not enough for this kind of diving. You should have doubles or something like that and you should be trained to manage failures.

Last month I was in Egypt. Everybody there was diving with single tank and single valve. I’m not sure if it there would be less or more incidents if everybody was using an y-valve. Do you think there would be less incidents if everybody was using an y-valve and two first stages?

If you can’t close your valves or close the wrong valve it still doesn’t solve the problems when you’re losing a second stage, have a leak or free flow.