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I was taught, as I suppose everyone is, to turn the cylinder knob back 1/4 turn after turning it all the way on. Never heard the reason for this though and am just curious.
AaronBBrown once bubbled... One reason is to prevent the knob from sticking open due to the pressure.
Yup.. same reason that when you screw down a locking gate carabiner that's going to be loaded.. you back it off half a turn or so. Those things have a nasty tendency to get way stuck when they're tightened down then loaded. I had to cut myself off a rope once because I forgot to
raxafarian once bubbled... just open it and leave it... don't crank it open HARD...
Pet peeve of mine to have a DM on a boat in the carrib. check my valve to be open, and then turn the valve back with a "flick of the wrist"
Yeah...SSI still teaches "1/2 a turn"
Gee...thanks for cutting off some of my air supply! I may not need it now, but when I breath a tank down to 150 psi because something went wrong I might.
how would a valve get stuck open when you just open it without cranking it open? Same with a carabiner, you screw it closed without cranking and LEAVE it, NO need to either turn the valve back or unscrew a carabiner, people have problems with carabiners because they load them and THEN screw them in further, yes, then you have a problem.
tankvalves, open them and LEAVE them, god knows how many people open a tank and then turn it back '1/2 a turn or so', i see divers almost CLOSE their valves doing that all the time.
So, NO dont close them whatever number of turns after opening, just dont crank a valve open and you will be fine.
Ari has the right idea. That 1/4 turn makes it easy during the buddy check to varify that a tank valve is open. I'm sorry, but the "restriction" caused by your valve being closed 1/4 or even 1/2 of a turn is so small I doubt it could even be measured.
cmay once bubbled... Ari has the right idea. That 1/4 turn makes it easy during the buddy check to varify that a tank valve is open. I'm sorry, but the "restriction" caused by your valve being closed 1/4 or even 1/2 of a turn is so small I doubt it could even be measured.
The problem is that many divers turn it back a lot more than 1/4 or 1/2 a turn. I do buddychecks but i dont want my valves touched unless i specifically ask my buddy to. And it is just as easy to verify a tankvalve is open when it is opened all the way, you do know what way to turn a valve to open and close it right?
...... a lot sooner than when you reach the end of the thread. Turning back a 1/4 or even 1/2 a turn does nothing to your air pressure, nor it will do anything about reducing the actual volume of air.
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