Lessons My sidemount cylinder valve spun itself completely shut during a dive

[J-Vo]

In open water or while navigating a restriction? The required motion seems pretty specific...

Both, but it was low/zero vis touch contact situation both times, so my arm holding the shoulder area of the other diver with my elbow down by my side. The big note is that this is a right-side issue, so you are rolling off the long hose. The first time I did this was in an air share situation in training.

 

[lexvil]

It’s diving, weird things can happen. Isn’t one of the selling points for side mount that the valves are easy to see?

 

[TNEngineer]

It's always bothered me that "off" rotation direction is application specific. Examples: To turn off (down) sound volume you rotate CCW. But to turn off air or water, you rotate CW.

"The nice thing about standards is there are so many different ones to choose from."

 

[tursiops]

@jstotz So what did your teammates say when you raised the subject of checking your valves?

By the way, the title of your thread really needs correcting; the valve did NOT turn itself off!

 

[rjack321]

I have personally rolled off my Sidemount tank on multiple occasions with simple arm motions. It is entirely possible, and I was even taught about it in my cave class.

I've rolled off many a suit gas bottle with my thigh, although they are quirky non-traditional valves on those 1L carbon fiber tanks so not a good example.

I have rolled off the right side SM tank once in an actual cave while in a sidewinder so I "lost" dil until I realized the issue.

 

[TNEngineer]

Could we fabricate a sort of "lift to turn" gadget to 1) prevent inadvertent adjustment, while 2) making it easy to adjust when intentional?

Most tank knobs have serrations around their circumference. A little gadget could engage those and prevent modest torque from turning the knob, yet be easily disengaged or defeated with more force.

 

[flymolo]

Could we fabricate a sort of "lift to turn" gadget to 1) prevent inadvertent adjustment, while 2) making it easy to adjust when intentional?

Most tank knobs have serrations around their circumference. A little gadget could engage those and prevent modest torque from turning the knob, yet be easily defeated with more force or disengaged.

there's more value in being able to quickly recognize when it's happened and then fixing it

 

[TNEngineer]

Unless it happens in tight quarters where access is awkward. Which, from reading this thread, is exactly where it's more likely to happen.

Not saying it's the only (nor even the preferred) answer, just an idea.

 

[flymolo]

Unless it happens in tight quarters where access is awkward. Which, from reading this thread, is exactly where it's more likely to happen.

that is exactly the reason for opposing valves. one rolls off whereas the other rolls on

 

[TNEngineer]

Granted. But if it weren't an issue this thread wouldn't exist.