Tank valve knob lock?

[WetSEAL]

and the consequences for those that need to quickly turn the valve off?

I'm not sure why you assume that a knob which has a rotation lock would take more time to close. That would really depend upon the design, but in my opinion a requirement of the design would be that it would not noticeably increase the time taken to manually close it (hence why I do not like the zip tie suggestion), would still be easy to operate using a single hand wearing thick gloves, and would not reduce the physical strength or robustness. I don't think those goals are unrealistic...

Is this problem *of which I am not aware of any documented deaths, only near misses*, worth risking the lives of those that need to turn off quickly for feathering *of which I can think of several where the several second delay in being able to shut the valve off could very well have killed the diver*.

If someone wanted to feather it, then they simply wouldn't lock it open. Anyone who's advanced enough to feather the knob can surely handle a single additional motion to unlock it first.

Another issue with this type of valve is that when doing things like ice diving, there is a high propensity for valve/regulator components to freeze. This type of valve if frozen while open would be completely unable to be shut off

We haven't even discussed the mechanism of the lock, so you can't really claim that it would be completely unable to shut off when frozen..

 

[tbone1004]

@WetSEAL I turn off a lot of SCBA valves. They take longer to engage than scuba tanks, even more difficult when behind your head.

You mentioned a 2-step operation, that is usually pull the knob out of an indent on the body of the valve and turn. Any sort of lock like that would require some motion other than rotational and a frozen valve would not like that. With 3d printing and cnc mills, go ahead and prototype one and try it. who knows, maybe we're all idiots

 

[WetSEAL]

For example, how about a simple rubber cap that goes over the knob, preventing it from rotation, but which can be easily pulled off with 1 hand?

 

[tbone1004]

For example, how about a simple cap that goes over the knob, preventing it from rotation, but which can simply be pulled off with 1 hand?

what would stop something like the anchor line from popping it off and then it's flopping around and not doing its job of stopping the anchor line from turning the valve off?

 

[WetSEAL]

what would stop something like the anchor line from popping it off and then it's flopping around and not doing its job of stopping the anchor line from turning the valve off?

They key would be to design it such that the direction of force needed to rip off such a cover is different from the direction of force needed to spin the knob, hence it would require 2 freak accidents of different types to first dislodge the lock and then spin the knob. Similar to the concept behind any external safety mechanism on a firearm which prevents accidental pulling of the trigger.

 

[MargaritaMike]

I just read the 35 posts ahead of this one. It kind of reminds me of a very good friend of mine who died in an aircraft accident aboard an aircraft carrier. After reading the results of the accident investigation it was determined that the accident was caused by a series of small mistakes which compounded to the point of catastrophe. After reading this I have it all figured out. His death could have been prevented if his parents had practiced birth control.
If a new valve with a special valve gets designed as mentioned above, please let me keep my old one. This old dog can't learn many new tricks. Thank you.

On another note:

I back off a quarter turn because I am able to figure out if a tank is open that way. All the way open and all the way closed feel the same to me. A 1/4 turn off of full open has a certain wiggle to it, so I can tell if the tank is on. I don't care if you do it differently. I just stay consistent with how I'm doing it.

A man after my own heart.

Cheers -

 

[scubarushu]

@WetSEAL You said you're a beginner diver. You're here asking for advice. You're stubbornly arguing with the people who have thousands of dives.

 

[AfterDark]

OP, diving 50 years and over 2000 dives the scenarios you described have not happened to me or anyone else I've dove with. The accident and incidents site here has zero incidents of any of the proposed scenarios happening. Thus a solution to a problem that is non-existent. With a valve fully opened it would take a lot of turns to close it, check it out count how many turns it takes to close it.

Believe me if it was a problem of any dimension some gear manufacturer would have come up with a profitable gimmick to "solve" it.

 

[AfterDark]

Okay, so it's happened to someone at least once...which pretty much nullifies any argument that "this is a non-issue."

Thank you for sharing.

It happened because a diver wrapped a hose around the tank valve that's not an accident, that's operator error. Big difference.

If you are really concerned the answer is carry a pony bottle more air is good.

 

[Russjstewart]

Out of the 300 people who've viewed this thread so far, already 1 of them has admitted that they got caught up in in something that caused his tank valve to accidentally close up....so although this is a small sample size, that suggests it's not so "impossible" as you suggest. Is it really a 1/300 event? Maybe not, but it's probably not 1 in a million either.

1 in 544 now

Good luck with your idea,but I wouldn't be buying one
Cheers