One-hand or two-hand valve drills (back mount doubles)

[L13]

the risk is the same - the fear will be different- dont ever recall having a free flowing reg thats already in my mouth - can it happen? and if its delivering gas why would you spit it out ?

All three of the free-flows I have observed at depth were in regs already in my buddy's mouth. These were the only times I have had to share air "for real."

 

[Alaskan Scuba Dude]

but i don't understand why anyone would spit it out

Recreational divers don't need to spit out the regulator since you have the option of feathering the valve all the way to the surface or just offset the free-flowing regulator as you breach the surface. Real technical divers have a decompression obligation and need to focus when problems arise.

I was taught isolator gets shut off first. Reasoning is that until we figure out what the problem is we want to at least preserve the gas in one of the tanks.

You were taught incorrectly. The problem is you don't have minutes to figure it out you have seconds. That is why the Zen master breathes slow and deep. Stick to CCRs if you dive deeper than your MOD on air.

 

[p_kos]

Recreational divers don't need to spit out the regulator since you have the option of feathering the valve all the way to the surface or just offset the free-flowing regulator as you breach the surface. Real technical divers have a decompression obligation and need to focus when problems arise.


You were taught incorrectly. The problem is you don't have minutes to figure it out you have seconds. That is why the Zen master breathes slow and deep. Stick to CCRs if you dive deeper than your MOD on air.

Disagree. If something goes pop and hiss behind you, shut down isolator 1st (while singaling team with other hand) and half your gas is fine while you figure out the problem. Unless your isolator valve exploded which will be apparent when you reach for it (now enjoy feathering your doubles!). Of course, if the leak is obvious (like the second stage free-flowing) go right for that post instead. It takes more than a few “seconds” to lose even half your gas, and you should now have your team ready to donate anyway (unless you lost them too, which means it’s truly not your day).

 

[Alaskan Scuba Dude]

It takes more than a few “seconds” to lose even half your gas, and you should now have your team ready to donate anyway

Work out your RMV after you subtract half the gas you thought you had when you're at 11 ata or deeper. Hopefully your imaginary team have enough gas, and are prepared to share, to get you to the next gas switch. Don't paraphrase every thing you read in a book.

 

[p_kos]

Work out your RMV after you subtract half the gas you thought you had when you're at 11 ata or deeper. Hopefully your imaginary team have enough gas, and are prepared to share, to get you to the next gas switch. Don't paraphrase every thing you read in a book.

Right…cause I would go to 11 ata or deeper with doubles and no team (you know, cause they’re imaginary for some reason). Get real. Don’t paraphrase every imaginary deep bounce dive no reasonable and properly trained diver would bother doing.

 

[Dark Wolf]

It has been 25 years since I have felt like I was high on mushrooms. Appreciate it!

DW

 

[halocline]

Recreational divers don't need to spit out the regulator since you have the option of feathering the valve all the way to the surface or just offset the free-flowing regulator as you breach the surface. Real technical divers have a decompression obligation and need to focus when problems arise.


You were taught incorrectly. The problem is you don't have minutes to figure it out you have seconds. That is why the Zen master breathes slow and deep. Stick to CCRs if you dive deeper than your MOD on air.

Even for you this is an absurd post, and you generally set the bar pretty high.

 

[Beau Holden]

what on earth do I practice in the pool in Calgary, Alberta, for the next 4 months?

Find you a buddy have him use his reg and start purging behind you and out of your sight. He can simulate first stage leaks and manifold leaks, making you chase them and determine where the leak is coming from.

 

[Beau Holden]

You were taught incorrectly. The problem is you don't have minutes to figure it out you have seconds.

Not saying you are right or wrong

In my full cave, the instructor simulated gas loss by purging his reg behind me. It sounded like it was coming from my right side. I couldn't tell for sure, reaching back, if it was from my first stage or manifold by feeling the bubbles. I shut down the isolation first then tank valve and switched to second. Bubbles and sound stopped. Same procedure for turning gas back on. Isolation first then tank valve, confirmed no leaks (bubbles) and back to primary.

Back on surface, the instructor said i must have been taught to shut down by wreck diving instructors, what ever that meant. Then he said "no worries, you got it sorted out in 15 seconds. Let's decide where the next dive is going to be."

In my opinion when the feces hits the fan, know what to do and how to get it done. In what order will be determined by the situation and resources at hand.

 

[boulderjohn]

When tech divers plan their dives, they plan plan on bringing oodles of gas to breathe. They should have plenty of gas to deal with an emergency even if none of their buddies help them. The amount of gas that would be lost in the amount of time it takes to shut down a valve would barely put a dent in that reserve.

Note that does not take into account the presence of buddies, because your planning should not include the buddies. You should plan to take care of emergencies like a leaky valve without the need for them. It is nice to have them there ready to help, but you don't plan on it.