Kevrumbo
Banned
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First read about it in some of the old Rec Scuba & Yahoo newsgroups; and AG mentioning it as a last resort contingency for overhead egress during my advanced wreck class in 2005 (but not actually performing the skill during training). The first time I actually did it was for real on single tank in Cozumel 2006 --and now occasionally practice it although I mostly dive backmount double manifolded AL80's here in SoCal homewaters.
Anyway, IIRC one post was in reply to George Irvine's suggestion of "pinching the hose" as an option to stop a non-fixable free-flow; the better solution came from a European DIR diver (Peter Steinhoff??) who recommended that on a reg-freeze free-flow to just shut-down the malfunctioning post (double manifolded cylinders). The main point is that gas is still accessible from that post, but you or a buddy would have to manually feather & manipulate the valve in order to control gas flow from it.
This is the reason why this skill should be taught at the beginning BOW/AOW level: If a novice diver on single tank at basic OW depth 18m/60' --with no buddy in sight-- has the option & ability and can successfully make the effort to conserve as much free-flowing gas by the valve modulation/feathering breathing technique, what he gains is time --time for the Buddy to find him and gas share. If not, then perform a "modified" Controlled Emergency Swimming Ascent (CESA) while taking breaths as needed by the valve modulation technique as described above. If possible & skilled enough to hold depth, do a safety stop. At the very least, the main objective is to safely reach the surface without suffering an AGE and with some tank pressure left to adequately inflate your BCD and Drysuit. You don't want an "out-of-the-frying-pan-into-the fire" SoCal worst case scenario of surfacing with an empty tank; getting tangled in kelp; inability to orally inflate the BCD because you're out-of-breath having just performed a conventional CESA; shrink-wrapped drysuit hampering mobility; and working hard treading water to maintain positive buoyancy in a typical prevailing 2' to 4' afternoon swell & wind chop --you had better at least be able to drop your weights!
To recap on an Uncontrolled/Unfixable Free-Flow:
Shut your tank valve down. When you need to take a breath, crack open the tank valve and shut it down again. Repeat as needed, switch to your back-up reg/octopus as well if the unregulated flow of gas from the malfunctioning primary reg is too much to handle. Perform this tank valve "feathering/modulation" technique while doing a CESA (if your buddy is nowhere to be seen and you're essentially solo). . .With your left hand, slow your CESA rate via BCD/wing hose deflator dump button . . .with your right hand reach back, feather/modulate your tank valve and take breaths as needed.
All it takes is practice (and IMHO --should be a mandatory skill taught in basic open water courses. . .)
The motivation after realizing that you can breath off a catastrophic non-fixable free-flowing 2nd stage reg, is to shut down the tank valve to stop further hemorrhaging of precious breathing gas. If you have a pre-dive Rock Bottom Gas Plan and you know how much pressure your tank has during all phases of the dive --you lose or become separated from your Buddy for an instant-- then why would you let vital breathing gas bubble away because of an unfixable free-flow on an emergency surface ascent? Especially if you have the ability to reach and manipulate your tank valve on & off to take breaths while not panicking, maintaining buoyancy at depth, spending a moment on the chance that your buddy will find you again? And if not, then how about a nominal ascent with a safety stop while still modulating your tank valve as needed for breaths?
The actual incident that happened:
Cozumel 2006, my adjustment knob on the second stage blew-out resulting in a catastrophic nonfixable free-flow, on a single-tank dive in 6m of depth, during a weightbelt lead check. I actually could see the gauge pointer/indicator hand on the SPG sweeping from 200 through 150 bar literally in an instant before reaching back to shut-off the cylinder valve. Switched to my bungied back-up reg around my neck and then modulated/feathered the tank valve behind my head while doing a CESA. (Again, this should be a skill regularly practiced starting in basic open water).
Thread Closed!!!
Unsafe Diving Practice advocated!
From our ToS
As of this point in time, no known agency currently teaches or advocates this practice and for many good reasons. Fortunately, many have already debunked this solution looking for a problem as being dangerous and overly taxing of a new diver's skill level so we'll be closing it and not simply deleting it. If at such time an agency includes it in their syllabus, we will reopen the thread.
Again:
This technique is not currently taught or advocated by any agency. Trying to make it work can cause injury and even worse: death. Please dive safely and take the advice of real instructors and not someone trying to prove something.
Anyway, IIRC one post was in reply to George Irvine's suggestion of "pinching the hose" as an option to stop a non-fixable free-flow; the better solution came from a European DIR diver (Peter Steinhoff??) who recommended that on a reg-freeze free-flow to just shut-down the malfunctioning post (double manifolded cylinders). The main point is that gas is still accessible from that post, but you or a buddy would have to manually feather & manipulate the valve in order to control gas flow from it.
This is the reason why this skill should be taught at the beginning BOW/AOW level: If a novice diver on single tank at basic OW depth 18m/60' --with no buddy in sight-- has the option & ability and can successfully make the effort to conserve as much free-flowing gas by the valve modulation/feathering breathing technique, what he gains is time --time for the Buddy to find him and gas share. If not, then perform a "modified" Controlled Emergency Swimming Ascent (CESA) while taking breaths as needed by the valve modulation technique as described above. If possible & skilled enough to hold depth, do a safety stop. At the very least, the main objective is to safely reach the surface without suffering an AGE and with some tank pressure left to adequately inflate your BCD and Drysuit. You don't want an "out-of-the-frying-pan-into-the fire" SoCal worst case scenario of surfacing with an empty tank; getting tangled in kelp; inability to orally inflate the BCD because you're out-of-breath having just performed a conventional CESA; shrink-wrapped drysuit hampering mobility; and working hard treading water to maintain positive buoyancy in a typical prevailing 2' to 4' afternoon swell & wind chop --you had better at least be able to drop your weights!
To recap on an Uncontrolled/Unfixable Free-Flow:
Shut your tank valve down. When you need to take a breath, crack open the tank valve and shut it down again. Repeat as needed, switch to your back-up reg/octopus as well if the unregulated flow of gas from the malfunctioning primary reg is too much to handle. Perform this tank valve "feathering/modulation" technique while doing a CESA (if your buddy is nowhere to be seen and you're essentially solo). . .With your left hand, slow your CESA rate via BCD/wing hose deflator dump button . . .with your right hand reach back, feather/modulate your tank valve and take breaths as needed.
All it takes is practice (and IMHO --should be a mandatory skill taught in basic open water courses. . .)
The motivation after realizing that you can breath off a catastrophic non-fixable free-flowing 2nd stage reg, is to shut down the tank valve to stop further hemorrhaging of precious breathing gas. If you have a pre-dive Rock Bottom Gas Plan and you know how much pressure your tank has during all phases of the dive --you lose or become separated from your Buddy for an instant-- then why would you let vital breathing gas bubble away because of an unfixable free-flow on an emergency surface ascent? Especially if you have the ability to reach and manipulate your tank valve on & off to take breaths while not panicking, maintaining buoyancy at depth, spending a moment on the chance that your buddy will find you again? And if not, then how about a nominal ascent with a safety stop while still modulating your tank valve as needed for breaths?
The actual incident that happened:
Cozumel 2006, my adjustment knob on the second stage blew-out resulting in a catastrophic nonfixable free-flow, on a single-tank dive in 6m of depth, during a weightbelt lead check. I actually could see the gauge pointer/indicator hand on the SPG sweeping from 200 through 150 bar literally in an instant before reaching back to shut-off the cylinder valve. Switched to my bungied back-up reg around my neck and then modulated/feathered the tank valve behind my head while doing a CESA. (Again, this should be a skill regularly practiced starting in basic open water).
A ScubaBoard Staff Message...
Unsafe Diving Practice advocated!
From our ToS
As of this point in time, no known agency currently teaches or advocates this practice and for many good reasons. Fortunately, many have already debunked this solution looking for a problem as being dangerous and overly taxing of a new diver's skill level so we'll be closing it and not simply deleting it. If at such time an agency includes it in their syllabus, we will reopen the thread.
Again:
This technique is not currently taught or advocated by any agency. Trying to make it work can cause injury and even worse: death. Please dive safely and take the advice of real instructors and not someone trying to prove something.
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