nereas
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They do this on TV and in the movies, but really not a good idea, actually.
Shutting off a single tank diver's air supply in a free-flow?
- Thread starter Dtaine
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They do this on TV and in the movies, but really not a good idea, actually.
dumpsterDiver
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Sounds like you've refined your thinking on this topic recently. I agree with your conclusion, however the applicablility of your recommendation seems limited to me. MOST recreational divers can NOT open and shut their tank valves, especially in an emergency. I'd be willing to bet that more than half of the typical recreational divers couldn't even handle buddy breathing from a single second stage during an emergency.
It is for this reason, that I think the prudent thing to do in a no-deco, typical, recreational setting is to abort the dive and not shut down the tank. Is salvaging the dive or saving a few bucks on a potential VIP worth the risk for most people?
SparticleBrane
Contributor
Actually it's quite a good idea to at least know how and to have practiced it. Who says your buddy (if you have one) will be around to assist you? If you have half a tank left and an LP hose blows, you're going to have your cylinder empty in a matter of seconds if you don't shut your valve down. Assuming the bubbles are a result of a regulator issue, feathering the valve allows you to save at least a good portion of that gas if you're in a situation that would required it.
Granted, in plenty of cases I would rather just shut the valve down and get on my buddy's long hose. Of course, this is assuming they haven't had issues that would preclude assisting me.
If nothing else, having the ability to feather the valve is just another tool in the "Bag of Tricks I Have but Hope I Never Need".
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While it's nice to be able to reach your tank valves, I'd be willing to bet that less than a quarter (probably a lot less) of OW divers have even tried it or could actually do it and that almost none would ever attempt it underwater for any reason.
In any case, it's not part of the OW curriculum, and given that most people never practice the emergency skills after getting certified, I'd be satisfied if the divers simply aborted the dive, did a safe ascent with buddy, and oral inflation with weight ditching on the surface if necessary.
If these were overhead dives, it would be a completely different story, but they're not. Why complicate things?
Terry
Last edited:
SparticleBrane
Contributor
In some courses, maybe...but not all.
Feathering a valve isn't complicated. It's actually quite easy. Then again if the diver is wearing their tank so that their valve is in the middle of their back, like many divers I've seen...
I'd rather see just about anybody share gas and ascend, than attempt to ascend on the free-flowing regulator. I think you're much better off on a solid gas supply, than on one that may be exhausted at any point during the ascent. A stressed diver, surrounded by bubbles and having difficulty seeing, who suddenly goes altogether out of gas, is a setup for panic, bolting, and embolism (to me, anyway).
I had enormous difficulty learning to manipulate my own valve on a single tank -- As it turned out, it was due to two factors. One, I had my tank too low in the bands (and I fixed that, and was able to do the valve drill to pass Fundies, but it was still labored and not NEARLY fast enough to be useful in an emergency). Two, my exposure protection was making my life difficult. In the Fusion, the drill is EASY. Given that the majority of divers dive in wetsuits, I would think it should be QUITE possible for them to reach and turn their valves, if a) somebody told them it was a useful thing to do, and b) they played with the tank placement until they could do it.
I had enormous difficulty learning to manipulate my own valve on a single tank -- As it turned out, it was due to two factors. One, I had my tank too low in the bands (and I fixed that, and was able to do the valve drill to pass Fundies, but it was still labored and not NEARLY fast enough to be useful in an emergency). Two, my exposure protection was making my life difficult. In the Fusion, the drill is EASY. Given that the majority of divers dive in wetsuits, I would think it should be QUITE possible for them to reach and turn their valves, if a) somebody told them it was a useful thing to do, and b) they played with the tank placement until they could do it.
John_B
Grasshopper
I'll bet you could find a dozen divers here on SB tonight who would tell you they dive piston first stages like the ubiquitous MK25 in water as cold, or colder, without ever having a freeflow. This wasn't ice diving.
If the diver can't handle sharing air and shutting off their valve long enough to thaw the regulator, how are they going to handle being OOG for real once their tank is empty? The point is to shut down the freeflowing regulator for a minute or two in order to stop the adiabatic cooling and let the water thaw the reg, not leave it shut off and continue the dive. Its not an emergency until you make it one by doing something stupid like an unnecessary CESA or ditching your buddy.
I'm finding this thread to be fascinating -- not so much for the content but for the mindsets and assumptions. The vast majority of posters seem to believe that the "average" diver is not very competent and can't be trusted to do an air sharing ascent without some problems. In addition, an additional prime assumption is that the "injured" diver's "buddy" is pretty damn worthless.
Given those assumptions, I suppose I'd agree that the best thing to do is to immediately go up with the hope that there will be enough gas to breathe from the free flowing reg all the way to the surface -- and that the free flow won't blast the mask off, won't rattle the diver in other ways and that she'll keep her wits about her NOT to cork and/or embolize because she got so nervous she actually forgot to breathe.
Me, MY assumption is that I'm going to have a competent buddy and that my buddy will kindly provide me with a working reg and then kindly turn off my free flowing gas. We will then exit from wherever we are and go to the surface in a calm and reasonable manner -- and if I need the gas that is still on my back, I'll be able to reach the valve and open it OR have my buddy (to whom I'm attached) reach over and open it.
Just a matter of assumptions, is it not?
Given those assumptions, I suppose I'd agree that the best thing to do is to immediately go up with the hope that there will be enough gas to breathe from the free flowing reg all the way to the surface -- and that the free flow won't blast the mask off, won't rattle the diver in other ways and that she'll keep her wits about her NOT to cork and/or embolize because she got so nervous she actually forgot to breathe.
Me, MY assumption is that I'm going to have a competent buddy and that my buddy will kindly provide me with a working reg and then kindly turn off my free flowing gas. We will then exit from wherever we are and go to the surface in a calm and reasonable manner -- and if I need the gas that is still on my back, I'll be able to reach the valve and open it OR have my buddy (to whom I'm attached) reach over and open it.
Just a matter of assumptions, is it not?
Y'all make this awfully complicated, gas plans, buddies, feathering valves (lol) and other foolishness.
The assumption from the beginning, single tank, no deco, no overhead. Since a diver who is working from a dive plan should never be in a circumstance to not have enough air to make a DIRECT ascent to the surface. A safety stop is NOT required, it is a safety stop, not a required deco stop. You can in fact travel to the surface at 60 FPM--DIRECT. An uncontrolled free flow for the diver following the Rule of Thirds should always have him with enough air to make a direct ascent from sport diving depths. You can breath just fine from a free flowing regulator. The proper thing to do is not fool around with feathering valves and looking for lost buddies and other time wasting activities but to instead signal an emergency to your buddy(s) and immediately initiate a controlled ascent to the surface breathing from the free flowing reg. If you absolutely must return up an anchor line rather than direct to surface that buddy better be on your six. The buddy should accompany you in the event your air supply exhausts before the surface is reached or otherwise assist as required.
Feathering valves, all that, yeah, whatever, sounds good, y'all try that sometime, I have and have done it, it sounds better than it works. The average diver would be better served to head for the surface---NOW---PRONTO. A free flow is not a panic situation for the non overhead diver unless you make it into one.
N
The assumption from the beginning, single tank, no deco, no overhead. Since a diver who is working from a dive plan should never be in a circumstance to not have enough air to make a DIRECT ascent to the surface. A safety stop is NOT required, it is a safety stop, not a required deco stop. You can in fact travel to the surface at 60 FPM--DIRECT. An uncontrolled free flow for the diver following the Rule of Thirds should always have him with enough air to make a direct ascent from sport diving depths. You can breath just fine from a free flowing regulator. The proper thing to do is not fool around with feathering valves and looking for lost buddies and other time wasting activities but to instead signal an emergency to your buddy(s) and immediately initiate a controlled ascent to the surface breathing from the free flowing reg. If you absolutely must return up an anchor line rather than direct to surface that buddy better be on your six. The buddy should accompany you in the event your air supply exhausts before the surface is reached or otherwise assist as required.
Feathering valves, all that, yeah, whatever, sounds good, y'all try that sometime, I have and have done it, it sounds better than it works. The average diver would be better served to head for the surface---NOW---PRONTO. A free flow is not a panic situation for the non overhead diver unless you make it into one.
N
OP
Dtaine
Contributor
Well, thank you everyone, this is certainly interesting. The only thing I'm wondering is if the scenario is changed a bit will the answers differ 
- so, here goes:
Say the free-flow doesn't happen to YOUR buddy, but you're on a dive with a bunch of newly certified OW divers (some of you might avoid these dives like the plague
, but nevertheless) and one of their regs starts to free-flow, rather than approaching their buddy they approach you and signal to air-share, etc. Would you turn their tank off in this situation?
Same environment as before, single tanks, no redundant air sources (aside from buddies), no deco dive, no overheads.
Yes I know there are a bunch of assumptions here, like that you're on that dive to begin with, the diver approached you and not his/her buddy, that the diver isn't panicking or attacking you for air, etc, but I would think that this is a plausible situation and I wouldn't be surprised to see a new diver go after a divemaster or more experienced diver for air should it happen to them.
- so, here goes:Say the free-flow doesn't happen to YOUR buddy, but you're on a dive with a bunch of newly certified OW divers (some of you might avoid these dives like the plague
, but nevertheless) and one of their regs starts to free-flow, rather than approaching their buddy they approach you and signal to air-share, etc. Would you turn their tank off in this situation? Same environment as before, single tanks, no redundant air sources (aside from buddies), no deco dive, no overheads.
Yes I know there are a bunch of assumptions here, like that you're on that dive to begin with, the diver approached you and not his/her buddy, that the diver isn't panicking or attacking you for air, etc, but I would think that this is a plausible situation and I wouldn't be surprised to see a new diver go after a divemaster or more experienced diver for air should it happen to them.
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