The Tank Valve Feathering/Modulation Technique

[Diver0001]

Actually, it's typically a better idea to NOT kink the hose. Most free-flowing second stages are caused by an IP that is too high.

Actually, I think this may be context dependent. I see multiple free-flows every year... because we dive in water that gets down to near freezing in the winter +/-2C.

The *vast* majority of free flows, especially vigorous ones, that I've ever seen have been caused by the 2nd stage poppet getting frozen open. Of those, the vast majority have been caused by momentary free-flows during the entry when the purge was activated. Those can be solved by turning off the tank for few minutes while the reg thaws and then turning it back on. About 10% have happened under water. In 30 years only one I've seen (while ice diving in the Czech Republic) was caused by a fist stage that froze open.

The only free-flows I've seen that were caused by IP creep were on some scubapro regulators a friend of mine had. He insisted on doing his own rebuilds but... well.. he wasn't very good at it. The regs he had already had a reputation for creep and all of his regs creeped some of the time. It became a running joke. IN all cases they caused "bubbling" the would increase to a certain flow rate. More of a hiss than a blow.... It could be characterized more as irritating than as an emergency.

I think if one lived in the tropics then the only free flows they would see would have to do with 1st stage issues or major malfunctions, so as I said, it could be context dependent.

R..

 

[victorzamora]

Actually, I think this may be context dependent. I see multiple free-flows every year... because we dive in water that gets down to near freezing in the winter +/-2C.

I guess I stand corrected, and that's good to know.

My impression was that even in cold water, the first stage was more likely to freeze open than the second stage. Either way, I don't know if I'd risk a hose blowing open if my initial guess was wrong....regardless of what I've seen as "more common."

 

[Diver0001]

I guess I stand corrected, and that's good to know.

My impression was that even in cold water, the first stage was more likely to freeze open than the second stage. Either way, I don't know if I'd risk a hose blowing open if my initial guess was wrong....regardless of what I've seen as "more common."

No, not at all. it's 99% second stage 2 problems.

To my way of thinking, the main risk in crimping the hose is that it will damage the hose.

R..

 

[lowviz]

Thanks lowviz, I'll keep the fold the hose trick in mind should I ever find myself with an unfixable free flow 2nd and need more time for a reasonable ascent. To date, I've never had a free flow while breathing off a reg, only very brief free flows when it was out of my mouth

Mild sarcasm noted. I, too, doubt that you will ever need this "skill". Just threw it in to give a couple of real-world times for draining a tank, -single 120's in the highly unlikely event that anyone cares. Strange thread...

 

[The Chairman]

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A ScubaBoard Staff Message...

Thread Closed!!!

Unsafe Diving Practice advocated!

From our ToS

ScubaBoard Moderators may at their discretion, remove any post which advocates unsafe diving practices as defined by the major certification agencies of the scuba diving world. While ScubaBoard does not take an official position on these matters, ScubaBoard does encourage users to maintain safe diving practices. You and you alone are responsible for your diving safety.

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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