Boat diving - Tank valve on or off during trip?

[CamG]

Greetings Phil and this is a good topic to bring up.
While in MX in 07 a DM turned my air off and back half thinking that I had it off already.
That was not the case we discovered this while doing a complete buddy check on the boat.
This was our first boat dives, first diver trip as well.
From that day on NO ONE TOUCHED MY VALVES BUT MY BUDDY OR MYSELF!
If the DM was persistent I would ask them to watch us gear up and listen to our pre-dive check.

Now that I dive doubles and or SM most of the time I set my tanks up on the dock, put them on the boat each time doing a pressure up and a SHUT DOWN!
Before I gear up for the dive I do a valve test turning both posts on and checking the isolator valve if there is one.
The only person who touches my valves these days is my buddy IF he is not sure or myself.
I am a anal and quite OCD about my valves, not so much about other items but still it is my dive mantra that is built to fit my diving practices.

I carry spare O-rings just in case and have used them as well as others on the boat.
IMOP as TSandM when the gas in on your back VALVES ON, when on the deck or bench VALVES OFF!
Simple rules are best.

BEWARE THE DM OR INSTRUCTOR ON THE BOAT WHO IS CHECKING VAVLES BEFORE ENTRY INTO THE WATER!
Be sure to breath from your regs before you enter the water watching your gauge or computer.
I always have my buddy check the valve is COMPLETELY OPEN before we descend or I will reach back and do it myself.

Dive safe and develop your own pre-dive mantra!

CamG Keep Diving....Keep Training....Keep Learning!

 

[Wookie]

Charged and off. Accomplishes the same thing your RIB divemaster wants to, IE the o-ring will blow if it's going to. Valve off means that you won't lose all your air if it happens.

Just for the record, in over 15 years of operating a liveaboard, I doubt I've seen 10 o-rings blow at the surface, and only 1 in the water. Never underwater during a dive. O-rings usually blow during filling.

 

[RonFrank]

It does not matter to me who does what when. The major thing I always check is to ensure the air is on before splashing. I've seen very few orings blow or leak. I rarely jump in and go straight down. When the dive dictates this (Current) I am extra cautious about checking air before I jump/roll....

 

[Mossman]

Thanks for the responses - not as controversial as I thought it might have been - I hadn't thought about battery life for the tank transmitter (I also use a air integrated computer), but I doubt the drain will be much, I seem to remember it stops sending if the pressure doesn't change for a certain period of time and resumes when it next changes. I have no pairing issue with leaving it on as it is permanently paired. The boat wasn't big, with six divers and gear with the boat crew and it was crowded. On at least one occasion a leak did occur without anyone noticing resulting in one diver having less air, but it was a checkout dive and short so didn't creat a problem, though I would have been unhappy if it was my tank. P

It depends on the computer. I have Suunto and Uwatec transmitters with long-life batteries so there's no real issue with leaving tanks pressurized. On the other hand, my old Cochran computers with bulky transmitters running AA batteries are definitely be affected by leaving them on a pressurized system.