Do you turn the air off or leave it on after setting up on a tank?

[johndiver999]

Valve on or off is not the problem. Do whatever you want.
The only problem (that is part of this discussion) is leaving a regulator pressurized with the valve off.
In a perfect world, everything done correctly every time, not a problem. But reality is things are not always perfect. Distractions do happen. Routines get interrupted. Checks get missed. It happens. Deny that it happens and you are setting yourself up for failure.
While depressurizing the reg when the valve is closed will not prevent everything, it will make a damn good indicator most of the time before something bad happens.

I cannot think of a single good reason why keeping a regulator pressurized while the tank valve is off is a good idea on a dive boat. Risk with zero benefit.

You sound so sure of yourself on this.... I agree with you completely.

 

[hedonist222]

I set up my gear - turn on tank - check air pressure on primary tank - pressure on secondary tank -
close valve

Then turn secondary tank on before primary (my way of ensuring my pony is not left closed by mistake)

I'm not a scuba gear technician, but is there a reason to keep both stages pressurized?
Unnecessary wear and tear?

20 mins per dive x 24 dives a month = 8 hours of your regulators pressurized

 

[Baker_Dive]

I like to turn my valve off but leave the reg(s) pressurized. However I have found myself in the water with my valve off doing this. This resulted in my hanging the reg by the necklace from the valve wheel as a signal to remind me to turn the valve on. Works, most of the time.

Dawg. Just leave the air on. Your misguided fear fear of losing a few psi does not OUTWEIGH the negatives of jumping in with a tank turned off.

You should also do three breaths while looking at the spg before ever entering the water. Which would of caught your mistake.

Also, how often do you surface with less than 800 psi? Most of my 40-60 minute dives I have 1000 psi or more left so losing a 50 psi is no big deal.

 

[Baker_Dive]

Yes. Bad things can happen. I've forgotten to turn my air on maybe 4-5 times back when I was fairly new to diving, but that's no problem if you're shore diving, just embarrassing to ask someone to turn it on. But you never want it off jumping from a boat.

Leave the air on once you set up the regs. So easy to jump in with it turned off and panic can ensue.

I have not heard one good reason on why it’s bad to leave it on. Only the misguided fear “I may lose a few psi” I say big whoop. Live to dive another a day. We are human and EASILY make mistakes like your 4-5 times.

 

[Baker_Dive]

You should carefully consider this assumption of "the stakes are not high". I would argue that the stakes are very high, in fact the diver may well DIE if they don't accomplish the task. You might feel the problem is easily fixed, but that does not mean that the stakes are "not high".

This is not a trivial point or semantics. What you may not realize is that some divers enter the water in a negative condition and may immediately begin a head first decent and some (advanced) divers might even consciously avoid inhaling deeply in order to stay as negative as possible for the first 10 or 25 feet of descent. So you could easily have a diver who is swimming down hard, sinking fast, takes a breath from the regulator, slowly exhales and now is even heavier and is 35 feet down and then pops his inflator a little and then tries to clear his ears and simultaneously tries to inhale and there is NOTHING. Nothing to breathe and there is no immediate solution to the negative buoyancy situation.

So now the divers is sinking, is heavy, his ears are hurting enough to be a huge distraction and will soon be subject to barotrauma and if he delays for 3-4 seconds more before figuring the problem out - his ear drum will rupture and now has to make the decision to
(a) drop weight,
(b) swim up like hell,
(c) locate his buddy and communicate the problem and secure a second stage
(d) locate and then switch to his octopus - obviously a bad decision in this scenario, but one that a diver might try in an emergency
(e) TRY to reach back and turn on the valve - even though his hands are full of expensive equipment

If the diver fails to immediately and correctly identify the problem and successfully employ the correct resolution with empty lungs and crushed ear drums, this could end very badly.

It is NOT a low stakes situation and it is NOT a necessarily trivial situation to extricate yourself from. Sinking out of control with nothing to breathe is a lot different than talking about turning on a valve on the internet. The complexities of this situation has caused people to die.

It is very important that people can reach and turn on their own tank valve, but the objective should be to never have to actually do it.

edit: This is one of the scenarios which makes me so nervous about people who "casually" will wear no ditchable lead. If they jump in with the tank off and swim down a ways, their options for making it home that day are significantly reduced.

All easily avoided if we follow training. LEAVE TANK ON WHEN YOU HOOK UP REGS.

TAKE THREE BREATHS WHILE STARING AT SPG.

Maybe I’m crazy but the casualness of people on here typing they turn it off to save a few psi is nuts to me. I’d rather know I have a leak on surface….

 

[Baker_Dive]

Well, I think you understood the scenario of cascading problems that I described, but you MIGHT have not caught the nuance of what I do (to help offset my propensity for stupidity and carelessness). After I set up and test: I PURGE the reg.

This step is done so that IF I forget to turn the tank on before I splash, I will get ZERO air. I hopefully will not get too deep without even one fart of air. In addition, IF I remember to check my spg before I splash, I will see ZERO air. IF I pop my inflator for a second before I splash, it will not work, If I tap my purge buttton it will deliver no air. This should signal to even the most distracted diver that they might want to check things. This amounts to exactly what you referred to as "layers of defense".

That is what I do and why I do it. Who knows if it is the best way, but it is what I try to do. I agree that if a diver does the proper pre-dive checks, valve position following set up is probably of little consequence.

Why even turn it off if reg is attached though?

 

[johndiver999]

LOL, it is not a few PSI. You should (probably) set the tank up while still at the dock - so if there is a problem you may be able to address it. Anyway, you should set up your tank an check it early.

Leaving the tank on for the ride out (20 minutes or 3 hours) while the seas are rough, waves are pounding stuff is shifting around.. very easy for a regulator to get bumped and start purging a little, You can lose a good bit of air like that. Better to have the tank off when running the boat to and between dive sites.

 

[BRT]

LOL, it is not a few PSI. You should (probably) set the tank up while still at the dock - so if there is a problem you may be able to address it. Anyway, you should set up your tank an check it early.

Leaving the tank on for the ride out (20 minutes or 3 hours) while the seas are rough, waves are pounding stuff is shifting around.. very easy for a regulator to get bumped and start purging a little, You can lose a good bit of air like that. Better to have the tank off when running the boat to and between dive sites.

I have seen this happen. On a noisy boat if the reg button gets pushed you can lose several hundred pounds before anyone figures out the noise.

 

[BoltSnap]

LOL, it is not a few PSI. You should (probably) set the tank up while still at the dock - so if there is a problem you may be able to address it. Anyway, you should set up your tank an check it early.

Leaving the tank on for the ride out (20 minutes or 3 hours) while the seas are rough, waves are pounding stuff is shifting around.. very easy for a regulator to get bumped and start purging a little, You can lose a good bit of air like that. Better to have the tank off when running the boat to and between dive sites.

Same here.

I check my equipment again as I am putting it on and turn my air on and when ready walk/jump into the water.

 

[Centrals]

All easily avoided if we follow training. LEAVE TANK ON WHEN YOU HOOK UP REGS.

TAKE THREE BREATHS WHILE STARING AT SPG.

Maybe I’m crazy but the casualness of people on here typing they turn it off to save a few psi is nuts to me. I’d rather know I have a leak on surface….

1. Set up the equipment and check.
2. Turn off the gas because the tank would have to be transferred to the boat.
3. A slight leak on a dive boat might not be noticed by everyone. 2hrs later!!!!
4. An misplaced elbow/hand on the purge valve can result a substantial lost of your precious gas.
5. Turn on the gas and check(buddy) before you are ready to jump.