free-flow - what to do?

[Crush]

Don't pre breathe regs, no sustained releases (lift bags etc.), slower inhalation and exhalation rates...

Excellent points. Our basic OW certification dives were done at 36F with an ambient air temperature below 30F. We were warned not to pre-breathe our regs until we were in the water and the regs (and our faces) were immersed in the water. The sharp inhalation which I normally do to watch for pressure fluctuations on my gauge (indicating that my tank valve is only partly open) is something which I do not do when diving very cold water.

 

[lowviz]

Excellent points. Our basic OW certification dives were done at 36F with an ambient air temperature below 30F. We were warned not to pre-breathe our regs until we were in the water and the regs (and our faces) were immersed in the water. The sharp inhalation which I normally do to watch for pressure fluctuations on my gauge (indicating that my tank valve is only partly open) is something which I do not do when diving very cold water.

Hafta love you guys, OW certed in conditions that make the US Navy take notice:shocked2: http://www.supsalv.org/pdf/ANU.pdf (search on 37 degrees)

FWIW, Just keep sticking with the Hitchhiker's Guide to the Galaxy's advice...

My advice: free flow -dive over.

Stay safe,
lowviz

 

[Rhone Man]

Recommended SOP for free flowing reg (assuming single tank, no pony, alternate second stage on reg):

1. Bang second stage against thigh/knee/other hand.
2. Bang second stage harder against thigh/knee/other hand.
3. Curse regulator liberally using names normally reserved for a mother-in-law who crashed the car.
4. Thumb dive.
5. Switch to alternate second stage and try and free flow by scrunching hose (having Miflex hoses helps...)
6. Share gas only if (i) you run out, and (ii) you can afford to buy your buddy multiple post dive beers. And then make sure you look reluctant about accepting it.

 

[Crush]

Recommended SOP for free flowing reg (assuming single tank, no pony, alternate second stage on reg):

1. Bang second stage against thigh/knee/other hand.
2. Bang second stage harder against thigh/knee/other hand.
3. Curse regulator liberally using names normally reserved for a mother-in-law who crashed the car.
4. Thumb dive.
5. Switch to alternate second stage and try and free flow by scrunching hose (having Miflex hoses helps...)
6. Share gas only if (i) you run out, and (ii) you can afford to buy your buddy multiple post dive beers. And then make sure you look reluctant about accepting it.

I can see banging helping with particulate-induced free-flow. I would guess that ice-induced free-flow would be more "sticky." Would you recommend banging for cold water (suspect ice-induced) free-flow?

 

[knowone]

OK.
If folding hose seems not to work, suggesting possible first stage problem, place alternate in mouth, CLEAR WITH EXHALATION and breathe slowly, maintaining fold in primary hose, which if done properly (and with excess air pressure now relieved and going into your mouth) primary reg air will be completely cut off.

With a first frozen open, if you fold a hose completely and pressure is not relieved elsewhere a lp hose somewhere will explode.

An inflator hose will explode eons before the schraeder gives and alternate inflator fittings have more balls than them.

How do I know? Other than the obvious, I have dun all that stuff and Lowviz may test it.
Well done Lowviz and with a bit more squeeze air will shut off completely.

OR

You could get a two bit degree and write a hypothetical thesis become a politician and preach only your ill informed ideas without an acceptance of other peoples

AND

Keep everybody simple stupid.

Wear muffs if testing in air.

Very good.

 

[lowviz]

..........With a first frozen open, if you fold a hose completely and pressure is not relieved elsewhere a lp hose somewhere will explode.
............

I'm counting on that. I feel that there is a bit of over-thinking on this whole thread. To me, an impending free flow means it is time to smile, say your goodbyes, cash in, pay the tab, and (sorry, don't know the Australian equivalent) GET OUT OF DODGE! Whether I fold the hose or not is up to me but you can bet your a$$, I'm getting out now! Why? Because loss of gas is a serious issue and losing a dive is not. Maybe I should have quoted Monty Python: Run away! Run away! Run away! (But do so without panic.:cool2

 

[flots am]

lowviz, FWIW I feel that you are right - I believe that most free-flows originate from the second stage, but my argument for this is not rock-solid. Can you reference any books or manuals? I agree with you because, in the case of ice-induced free-flow, ice formation cannot occur ex nihilo. That is, there must be some water vapour present from which to form ice.

First stage freeflows occur because the adiabatic cooling caused by the pressure drop from tank pressure to intermediate pressure freezes the water inside the first stage, preventing the valve parts from moving. The water that freezes is the water you're diving in.

A sealed first stage (several methods including positive pressure and various greases/compounds) prevents this by eliminating water inside the first stage.

No amount of hose kinking, shutoff valves, disconnects or anything else that happens downstream of tank valve will fix an in-progress first stage free-flow.

Second stage freeflows are caused by improper or lack of service, contamination, diving into current (fast moving water depresses the diaphragm on regs not designed for this) and diver error.

flots.

 

[NC Wreck Diver]

If it is getting really nasty, shut down my isolation valve and pick up my octopus from the other post. If it's just annoying, breathe the freeflow reg to the surface. I have my 30 sling bottle, which is on, just to keep my redundancy.

In all cases, for me, dive over. The wreck will still be there until my gear is straightened out.

 

[knowone]

I agree.
It's GET OUT OF DODGE.
Quietly with minimal disruption.