Can you swap a tank underwater?

[Crush]

Further to the discussions at http://www.scubaboard.com/forums/basic-scuba-discussions/309572-darwin-awards-diving.html :

Is is possible to swap a tank underwater? Not hypothetical - have you done it, and if so, are you still reasonably un-scarred? Are there any reg setups which are specialized to be able to accomplish this?

My basic OW instructor told us that, if water enters the 1st stage, attaching this reg to a fresh bottle and opening it up will accelerate the plug of water to an incredibly high speed, leading to the likely rupture of your gauges. I have thus far not felt the need to try to prove him wrong with my own gear (although perhaps I could rent his...).

Has anyone done this and survived?

Thanks

 

[zaberman1]

You may want to check this out:

http://www.scubaboard.com/forums/instructor-instructor/309599-swapping-tanks-while-underwater-submerged.html

It is very possible...

 

[StreetDoctor]

There shouldn't be a need to ever swap tanks while underwater although I've heard of people swapping regs on deco bottles for one that is functioning properly.

 

[MXGratefulDiver]

My basic OW instructor told us that, if water enters the 1st stage, attaching this reg to a fresh bottle and opening it up will accelerate the plug of water to an incredibly high speed, leading to the likely rupture of your gauges.

Your basic OW instructor misinformed you.

... Bob (Grateful Diver)

 

[emoreira]

You may want to check this out:

http://www.scubaboard.com/forums/instructor-instructor/309599-swapping-tanks-while-underwater-submerged.html

It is very possible...

That post is not available to me :depressed:

 

[zaberman1]

Possible but not generally recommended because you'll get some water into your first stage (and subsequently your mouth). The amount depends on such things as the model of regulator and how much you change depth (and in which direction) while the regulator is off the valve. You'll get the least amount of water if you slowly ascend and use one of the new-fangled regulator models that provides a seal over the sintered filter.

Reg removal and replace was a semi common confidence building skill when I certified in 1978, as was breathing directly off the tank valve. There isn't enough water introduced into the first stage to be noticed when breathing the reg after it is reattached.

On a dive I was on in Cozumel, the DM had an O-ring extrude on his DIN valve regulator. He pulled his BCD off and I held in in place while he shut the air off (using mine briefly), took off the reg, fixed the O-ring, put the reg back on, and replaced the BCD. He thought about continuing the dive, but finally decided he had lost too much gas and went back to the surface for a tank switch.

it is possible and taught during my tech course (mostly for fun and not performed while submerged) to switch between stages/bottles...

I don't think this is strictly 'instructor worthy'...

 

[Graeme Tolton]

Typically though, anyone who is bringing multiple tanks on a dive, is bringing multiple regs, pre-attached to those tanks. The regulator would certainly have to be serviced after.

 

[SurDo2]

I've done it several times. It's no big deal.

 

[Dr Wu]

Sucks for the reg but it will be fine to use for a while.

 

[Doc Harry]

It's not good for your regs or cylinders, but it can be done.

I've taken off my first stage and replaced it underwater, to stop a leak.

The regulator needed a good cleaning afterwards.

The cylinder -- don't know, it was a rental!!!!!!!