Keeping Isolator Valve Closed

[Gary]

Have any of you practiced swapping regs between your sidemount tanks underwater? Hopefully somewhere safe like a pool? I mean without a third regulator/stage of course. It sounds like it would be pretty scary to have to do that in a cave!

I've had to swap regs once on a deco bottle due to a reg failure but no problem there of course. I also use 200 BAR DIN fittings so it doesn't take 3 hours to screw out the DIN fiitting.

Practicing such a skill seems more likely to cause an eventual regulator failure to to mistreatment of gear then to significantly help in an accident when you should always have sufficient air in the unaffected tank to swim out without having to do any regulator accrobatics.

In addition to having a 3rd regulator along (stowed or on a stage/safety bottle) some people like to have one of their sidemount bottles with an H-valve and 2 regulators like a mini doubles tank.

[FW]

Have any of you practiced swapping regs between your sidemount tanks underwater? Hopefully somewhere safe like a pool? I mean without a third regulator/stage of course. It sounds like it would be pretty scary to have to do that in a cave!

It would be scary. It is considered as a desperate last chance option. Hopefully, you could buddy breathe a minute while you did that. There is also a risk that the reg will be damaged in the process.

A safer thing is "valving" air. I guess I should have explained that a little. If you have a reg that is free-flowing badly, you can turn the air on, get a breath, and turn it back off. I would like to see Skip try that backmount, while swimming out of the cave

I have had to do it a couple of times, and even with sidemount, you end up with a CO2 headache. I could have swum out on one tank, but it is safer to use the air in both tanks, that way you are guaranteed to have enough to negotiate tight spots, and still get out.

[FW]

I dove with some Australians in Mexico. They were used to diving independents. They started the trip with the isolator fully closed. Then they went to a just barely cracked open isolator. By the end of the trip, they just left it open.

If you are really concerned about loosing all your gas, you should go sidemount, not back mounted independants. At least you can reach the valves. You can also "valve" air out of one with a freeflowing reg, which you can't do backmount.

Let's look at this again

I think some people missed the most important part of that statement. In spite of all preconceived notions about independants, the Australians ended up just using the manifold as it was designed !!

[Gary]

A safer thing is "valving" air. I guess I should have explained that a little. If you have a reg that is free-flowing badly, you can turn the air on, get a breath, and turn it back off. I would like to see Skip try that backmount, while swimming out of the cave.

Actually my reg exploded on a dive in Mexico just at "repair shop" sink (no egress).

Rental tanks so I had a manifold but as the reg that was effected was attached to my inflator I ended up "valving" the reg to power inflate. I could "valve" to pressurize the hoses and leave it til needed next. It was so easy to do we turned the dive but took our time with the exit.

Worst I could imagine would be a cramp in my arm from reaching back over my head if I had to do it to breathe for more then 20-30 min. More likely just swaping tanks frequently would be plenty of rest. Guess it depends on how well you can reach your valves.

But you are right. There should never be a need to swap the regs instead of just "valving" it - unless the reg was in such bad condition you couldn't get air from it at all and the working tank was for some reason nearing empty.

[Line Squirrel]

A safer thing is "valving" air. I guess I should have explained that a little. If you have a reg that is free-flowing badly, you can turn the air on, get a breath, and turn it back off.

Us yankees call it "throttle the valve" like on a motorcycle

[DeepBound]

A safer thing is "valving" air. I guess I should have explained that a little. If you have a reg that is free-flowing badly, you can turn the air on, get a breath, and turn it back off. I would like to see Skip try that backmount, while swimming out of the cave

Oh that's what you meant. Up here we call it "feathering the valve", but I don't know why. I actually thought you meant that you coudl take the malfunctioning reg right off and just breathe off the tank valve!

[FW]

Oh that's what you meant. Up here we call it "feathering the valve", but I don't know why. I actually thought you meant that you coudl take the malfunctioning reg right off and just breathe off the tank valve!

You can do that too, but it is pretty hard to swim that way.

[David Brock]

Shadowjack - could you give some more detail about the "explosion" failure. Did it happen at a weak point like a port and where there any special circumstances?

Catastrophic failure of a regulator is pretty rare and it would be informative to get some objective information in this area. IRAPs has very little on this.

[skip]

check the threads on Challenge questions. the first one includes the details of a reg exploding on Cindy B....and another one is in there too if i remember correctly.

-skip