Boat diving - Tank valve on or off during trip?

[Tigerman]

Really?! I doubt I've seen ten O-rings blown in several hundred surface intervals in the tropics.

Guess youre either lucky or dive with people who dont leave their valves open then


Edit: Actually, theres a third option - DIN valves, as they are harder to blow than yoke ones..

 

[aquaregia]

I leave the valves off but pressurized. I wouldn't recommend this to others as I've forgotten to reopen the valve and had it caught in the buddy check. I was lucky I had a good buddy those days.

 

[oreocookie]

I leave the valves off but pressurized. I wouldn't recommend this to others as I've forgotten to reopen the valve and had it caught in the buddy check. I was lucky I had a good buddy those days.

If you wouldn't recommend it and have forgotten to reopen the valve, why do you do it? How difficult is it to push a purge button for a second or two?

 

[ktomlinson]

I always pressurize when I set up my gear,and leave it open. If your gear leaks or if it blows orings because of this you should have it repaired.

 

[DuboisP]

OK, don't shoot me down in flames if different organisations have strict views on this but I have had different opinions.

When diving from a medium size rib one instructor I have dived with always get the bcd and tanks loaded onto the boat with the air valve open - she says if an o ring is going to blow then it usually happens fairly soon after pressurising and this is the best way to be sure it won't happen during the dive. However other people I have dived with only turn the valve on just prior to getting in the water, saying, with some justification because I have seen it happen, that a regulator or octopus can get knocked or held open slightly and lose air on the trip out.

the 2 are corrects.
i'm using DIN regulators, so the risk to have a o-ring problem is near 0.
it's depending also the size of the boat and the place for the hardware.
big boat with a lot of place, can be open.
small boat with a lot of divers, always closed.

and don't forget to open the valves / check the pressure.

 

[The Chairman]

The easy answer to this conundrum is "Yes, you should either run with the valve open or closed!" Rly, as long as you are consistent with your final procedure, you'll be just fine. There are nearly as many reasons to do it as not, so its mostly a matter of personal preference.

 

[randy88k5]

I always set the gear up while at the dock or on the way to the dive site. I pressurize and test everything, then purge the system, checking to see the gauges go down to zero. I open the valves before gearing up for the dive, and check the gauges again. I can also reach my valves to turn them on or off as necessary, but I wouldn't rely on that as a pre-dive step.

 

[Hatul]

I like the system of pressurizing after assemby checking the pressure and both regs, then close valve and depressurize. Before donning open the valve again check pressure again and after donning check the reg again watching the SPG. Depressurizing helps guard against having the valve closed and an SPG reading full.

 

[Phil_C]

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

 

[cloudflint]

I always like to preassureise the system then switch it off and leave it a bit before heading out, that way if it has a leak anywhere ill be able to see from the pressure drop. Most of my diving is off a rhib so we usually end up with peoples rigs piled up on top of each outher on the deck and it gets quite cramped so for that reason I turn my valve off just because if i dont you can garuntee somebody or something will hit the purge on the reg If there are only a few of us going out and we have more space i generally dont mind leaving the system turned on, whatever works.