pennypue
Contributor
u-boat853:
I'm at a 100, I'll sign it twice.
:rofl:
Doing it Ridiculous
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I'm at a 100, I'll sign it twice.
:rofl:
Kim:
Kim -- What "massive 1st stage failure" is going to be solved by turning the valve off?
If the air in the tank is not going to be useable, I'd rather not be spending the time, energy, remaining breath in my lungs turning the valve off. There's either an alternate air supply to provide time to do mechanical mucking about (buddy, pony, isolated second tank), else it's time to do a Hail Mary ascent. Are you thinking about something like a first stage freeflow? What's the actual likelihood of that clearing by one or two on-offs? (risk/benefit -- since it takes multiple turns on the valve to shut it off, we're talking a serious number of seconds here. I'd personally hate to spend 10 seconds of my last breath trying to turn the valve off then on again, only to find I'm still hosed, that it was an o-ring blowout or some such, not cured by an on/off)
(I'm asking this out of real curiosity, a serious question, trying to understand a major failure that's going to deplete your tank in seconds, yet can somehow be cured by turning the valve off, and the remaining air in the tank will somehow then become accessible again.).
As much as I hate introducing any serious information into what has largely been, and probably should remain, a tongue-in-cheek thread, I do want to say that our DIR-F instructor yesterday told us that they have reviewed the valve drills for single tank users and come to the conclusion that we do NOT have to show we can turn the valve all the way off, but only that we can turn it on. So I guess even GUE has decided that there aren't very many reasons to be able to turn off the valve on a single tank. On the other hand, if you're unfortunate enough to jump off the boat with your air off, you might really enjoy the ability to turn it on . . .
pennypue
Contributor
:monkeydanu-boat853:
That's where Mr. Ed, my pony, comes into play Always carried, inverted, turned on, and even if I somehow had both main tank and pony off, the pony valve is really easy to reach -sweep my right hand back and the valve is immediately in front of the pony hose.
Always carried, inverted, turned on, and even if I somehow had both main tank and pony off, the pony valve is really easy to reach -sweep my right hand back and the valve is immediately in front of the pony hose.
markfm:
I once had a "single" tank free flow on me coming up from a 140' dive. It was a deco bottle that started to free flow around 70', probably because I was over breathing it. My buddy was fooling around with the light bag around 90' and stalled the ascent, so I started to get a little anxious. He also tried to deploy the liftbag with his light deployed, so I ended up holding the bag while he sorted himself out. When we did the gas switch at 70', my reg started to free flow, so I had to feather the valve and try to slow my breathing down to a normal level. By the time we hit the 50' stop, the reg was fine, but I was thinking what a pain the leg the whole thing was. Of course, as a contingency, my two other buddies had enough gas to share and we each had cut backup tables for a lost deco gas contigency.
There were a whole host of other problems on that dive...
markfm:
This seems like a good point to me, especially when you consider that once that thing has been freeflowing, it's going to be very cold, and quite likely to keep misbehaving until it warms up again somewhat.
Which is going to take minutes.
markfm:
first of all shuting down a valve should not take "many" seconds. To be effective it needs to be fast but tanks don't empty as fast as you might think even with wide open valves. Try it.
A free flow (first or second stage) caused by freezing sometimes thaws quickly once the free flow is stopped. With a single tank and a single port valve that means you need to switch to another breathing source. But...lacking another source you can feather the valve to breath from a free flowing reg and make your gas last longer. Try it. Once you learn to reach the valve it isn't hard to do and can come in prety handy.
IMO, the real value of a single tank diver being able to reach his valve has more to do with being able to turn the valve on than off. Regardless of how the valve ends up getting turned or (or partly off) it sure is nice to be able to easily reach back and turn it on.
BTW, IMO, some valves including the some found on manifolds require way to many turns and some are WAY too hard to turn especially in the cold where your muscles give out easier. Some can be fixed up some but others are better being replaced.
Ahh, but you're in the tech zone, multiple bottles and regs.
For a normal OW diver, single tank, no deco obligation, I would expect to go to breathing from the bubbler, immediate ascent, controlled. Good to be able to reach your valve and try feathering in such a case? Sure. Life or death (or serious bends risk)? I'd expect not -- this shouldn't be an empty-the-tank-in-seconds scenario.
(Actually, I'd personally go to my pony, but that's cause I'm a wimp, don't play in deco land.)
Edit -- I was responding to do_it_easy, before Mike's post. No disagreement with either post, just the criticality level. For me to have the turn-it-on issue I would have had to have multiple sequence failures:
1) Didn't do the final breathe-the-reg-while-watching-SPG check prior to entry.
2) Didn't inflate my BC prior to entry, so that I'm starting positive.
3) Didn't have my pony, second air source.
I don't deny, by any means, that being able to turn it on is good/useful, just that it is unlikely to be a killer. Especially in my drysuit, I find fiddling with the valve a pain in the butt, and anyone with any range-of-motion issues might well find it near impossible.
For a normal OW diver, single tank, no deco obligation, I would expect to go to breathing from the bubbler, immediate ascent, controlled. Good to be able to reach your valve and try feathering in such a case? Sure. Life or death (or serious bends risk)? I'd expect not -- this shouldn't be an empty-the-tank-in-seconds scenario.
(Actually, I'd personally go to my pony, but that's cause I'm a wimp, don't play in deco land.)
Edit -- I was responding to do_it_easy, before Mike's post. No disagreement with either post, just the criticality level. For me to have the turn-it-on issue I would have had to have multiple sequence failures:
1) Didn't do the final breathe-the-reg-while-watching-SPG check prior to entry.
2) Didn't inflate my BC prior to entry, so that I'm starting positive.
3) Didn't have my pony, second air source.
I don't deny, by any means, that being able to turn it on is good/useful, just that it is unlikely to be a killer. Especially in my drysuit, I find fiddling with the valve a pain in the butt, and anyone with any range-of-motion issues might well find it near impossible.
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