Kinking over hose to stop freeflow?

[rick00001967]

Having a buddy close a tank valve while sharing air can pose a risk to the OOG victim if the two might separate for some reason, if the victim can't or doesn't turn their own gas back on.

If a buddy team is going to use that protocol, it should be agreed upon in advance, and each buddy should be able to manipulate their own valve.

the same risk is there during any oog air sharing situation.

agreeed

Is there a agency that has this skill in standards or the instructor guide?

The vast majority of people learn to breathe from a free flowing reg, but none actually learn what to do when it happens.

if two people breathing off a single air source then there is a chance of causing the the donor’s reg to free flow. So, it is preferable to the initial diver to continue breathing off his/her reg while making the ascent.

i am not commenting on whether it is part of any agencies training. i am saying that some divers may choose to close the tank valve before all the gas is lost. i have also seen regs that functioned fine after having the tank closed for a few minutes. especially if the second stage had become a problem due to ice build up.

yes we also teach our students to breathe from a free flowing reg. and yes there should be a discussion at that point about what to do next.

yes there is a chance of the second divers reg having the same malfunction. over breathing the first stage in very cold conditions may cause a problem. but what are the odds in this ? and as i stated above in the previous comment, the same risk is present during any oog air share sceneario.

 

[grf88]

SNIP
yes there is a chance of the second divers reg having the same malfunction. over breathing the first stage in very cold conditions may cause a problem. but what are the odds in this ? and as i stated above in the previous comment, the same risk is present during any oog air share sceneario.

I have seen that happen on more than a couple occasions in cold water and in two cases it resulted in a rapid ascent.

 

[J-Vo]

I was taught in OW/AOW to breath off a severed LP hose using a kink to control the flow. I was told this simulates a hose rupture. I doubt it was an agency skill. I also doubt you could control a first stage HP breakthrough via this method. We also learned to breath directly from tanks.

I would feather the valve today, but I'm in side mount. For single back mount, I may consider a kink to breath from the hose while doing an emergency ascent, but I haven't dove single back mount in years.

 

[doctormike]

this is why you should always be able to reach your valve knobs. Reach back and turn the valve off. Then open back on to feather as necessary. SOP in cave diving, not so much anywhere else. Kinking the hose can't be considered reliable, particularly in extremely cold water with thick/squishy gloves and limited dexterity.

I don't think that you are considering the scenario where kinking the hose would be helpful. Standard recreational rig: Single tank, two second stages on LP hoses (primary and octopus), and a LP hose to the BC.

So if you have an unrecoverable free flow from either second stage, or a burst of any one of the three LP hoses, your AL80 will be empty in seconds unless you stop that leak. It's true that shutting off the valve and reopening might stop the free flow, but it also means that you have no gas at all when the valve is closed, and if the diver has a problem reopening the valve, it's CESA time. I can certainly see how that might set up a panic spiral in a relatively inexperienced diver.

I don't know if anyone actually teaches it, but at least kinking the hose is quick and leaves the other single stage delivering gas. Probably better to fix the free flow, but not an unreasonable emergency procedure to know about. I would replace my hose after doing that, though...

 

[lexvil]

Kinking doesn’t work with all hoses, modern hoses won’t work, a recent incident proved this to me so you may want to test your particular hose.

 

[Ayisha]

the same risk is there during any oog air sharing situation.

agreeed.

Yes, but in the case of a freeflow and separation with the valve off, the victim could have still had access to freeflowing gas as opposed to if they were OOG already.

I'm not saying not to do it. It was my protocol for years and it's fine for people on the same page. I'm saying that it may not be for someone who is not aware that someone might close their valve or if it is not known whether the victim can manipulate their own valve. Communication is key.

 

[rick00001967]

it may not be for someone who is not aware that someone might close their valve or if it is not known whether the victim can manipulate their own valve. Communication is key.

100% agree

 

[tbone1004]

I don't think that you are considering the scenario where kinking the hose would be helpful. Standard recreational rig: Single tank, two second stages on LP hoses (primary and octopus), and a LP hose to the BC.

So if you have an unrecoverable free flow from either second stage, or a burst of any one of the three LP hoses, your AL80 will be empty in seconds unless you stop that leak. It's true that shutting off the valve and reopening might stop the free flow, but it also means that you have no gas at all when the valve is closed, and if the diver has a problem reopening the valve, it's CESA time. I can certainly see how that might set up a panic spiral in a relatively inexperienced diver.

I don't know if anyone actually teaches it, but at least kinking the hose is quick and leaves the other single stage delivering gas. Probably better to fix the free flow, but not an unreasonable emergency procedure to know about. I would replace my hose after doing that, though...

what are the odds of that happening though? Most of the time the freeflow is caused by the first stage having IP creep for whatever reason, so if that is the most likely culprit of the freeflow, then kinking the hose won't stop that problem. Reach your tank valve and feather it, if you can't, then make a direct ascent to the surface, or start air sharing with your buddy.

 

[doctormike]

what are the odds of that happening though? Most of the time the freeflow is caused by the first stage having IP creep for whatever reason, so if that is the most likely culprit of the freeflow, then kinking the hose won't stop that problem. Reach your tank valve and feather it, if you can't, then make a direct ascent to the surface, or start air sharing with your buddy.

I mean, I don't know the odds, but the point is that unstoppable free flow is an actual thing that actually happens. And what might be stoppable to you might be unstoppable to a new diver, and empty the tank in seconds.

So assuming that the diver has a kinkable hose, telling them to just kink it and breathe from the other reg to break the panic spiral and make it to the surface doesn't seem like a terrible idea to me.

Again, I'm not an instructor, so let me know if I'm off base here. But I do NOT think that it's a good idea to teach the average recreational single tank diver (who might dive one week a year if that) to mess with their tank valve underwater. It's hard enough for committed divers learning doubles to get that right.

I just really don't see the downside here...

 

[tbone1004]

@doctormike like I said, the most probable cause of an unstoppable freeflow is IP creep from the first stage. If you have one of the second stages freeflowing and kink it off, the other one is just going to start freeflowing. Looking at it from a probability of failure mode scenario, it's not a technique that would solve the most likely culprit of the freeflow, so why emphasize it? If we are talking strictly recreational diving, their training should be to start sharing air with their buddy and make an ascent to the surface, not to try to resolve that problem underwater. We teach our students that if that happens, to start sharing air, and once you are stable, then turn the tank valve off since it's obnoxious to deal with, but we also emphasize proper tank placement on the BC so they can comfortably manipulate the valve