How much do you open your tank valve?

[tursiops]

ALL THE WAY ON!!! It is either ON or OFF no x/x turn back. That has gotten people injured or killed. There is NO reason to do it.

That's certanly an extreme, all-or-nothing statement, which of course is wrong. If you're on a dive boat, and the DM is quickly checking your tank before you giant stride, a 1/4 turn back allows for a fast check. I'm not saying I like that, but it is rather common. Turn you tank all the way on and see what happens when he does that. THIS is when you can get the hurried, confused DM who feels nothing, so turns it all the other way (off) and then back on a 1/4 turn. Bad juju. Just let him have his fun, don't confuse him. Oh, and don't shout, there is NO reason to do it.

 

[Magnus Lundstedt]

That's certanly an extreme, all-or-nothing statement, which of course is wrong. If you're on a dive boat, and the DM is quickly checking your tank before you giant stride, a 1/4 turn back allows for a fast check. I'm not saying I like that, but it is rather common. Turn you tank all the way on and see what happens when he does that. THIS is when you can get the hurried, confused DM who feels nothing, so turns it all the other way (off) and then back on a 1/4 turn. Bad juju. Just let him have his fun, don't confuse him. Oh, and don't shout, there is NO reason to do it.

A person who cannot differ between closing and opening a valve should not bee touching it in the first place.

Thats why i check that is it al the way open before i deccend.

 

[broncobowsher]

Accidently turned the valve off, as compared to not opening the valve. I'm sure there have been a lot more valves turned on at the last moment that have saved a lot more people then the oddity of a valve turned off. The valves being turned on really don't get any reporting, but turn one off and the internet is broken.

No, don't check my valve. If it is off it is my problem. I never do anything wrong. You always screw up everything you touch. When I sink without air don't come to save me either.

 

[TMHeimer]

Accidently turned the valve off, as compared to not opening the valve. I'm sure there have been a lot more valves turned on at the last moment that have saved a lot more people then the oddity of a valve turned off. The valves being turned on really don't get any reporting, but turn one off and the internet is broken.

No, don't check my valve. If it is off it is my problem. I never do anything wrong. You always screw up everything you touch. When I sink without air don't come to save me either.

Well yeah, but it's all probably a matter of liability and percentages. The dive op may have a rule for DMs to check all divers' air because it's like you said, far more likely that it winds up saving a diver rather than drowning one. Maybe I'm just pessimistic. Maybe they play the %s because it's just the right thing to do. Maybe.
I haven't been on a charter since 2015. Can't recall now how often a DM checked my valve.
I think it's just a policy thing with some ops. There are a whole lot of other things that can go wrong that they don't check.

 

[Blasto]

Turn you tank all the way on and see what happens when he does that. THIS is when you can get the hurried, confused DM who feels nothing, so turns it all the other way (off) and then back on a 1/4 turn.

What you're describing is a case of mismatched procedures: the diver was doing full off, the DM quarter-turn.
Procedure mismatch is more dangerous than either procedure followed. If your boat has a set procedure one way or the other, don't be a hero, just follow whatever it is.

But you also inadvertently illustrated why the quarter-turn procedure is a bad one to have. If the same happened in reverse, the diver would've noticed it while prebreathing from the reg before splashing.

With the 1/4 turn procedure, it's all that needs to go wrong to have a problem. With the full-on procedure, 2 more things need to go wrong: the diver to skip reg check and the diver to forget to inflate their BC.

The safest procedure, of course, would be to do a full-on and for the BM/DM to "fail" the diver who has their air off - send them back inside to open the air and do a new self and buddy check. That way no one outside the team is messing with the valve, and the divers are getting trained for self-sufficiency.

But of course this procedure is too 'expensive', as it increases boat turnaround time. To speak nothing of indicator valves, which outright eliminate the problem... but they'd have to come standard with the tanks, dive ops won't replace their whole inventory over this.