PADI-Sipping Air Free Flow?

[Storker]

It's hard to do a 100 foot dive on an Al 80 if you adhere rigidly to "minimum gas" (aka "rock bottom") philosophy.

I've found out that my min gas time correlates surprisingly well with my air NDL (drysuit, ~100CuF single tank). These days I'm usually on EAN32, but I still plan my bottom times as if I were on air. That way I stay reasonably close to min gas limits.

 

[PfcAJ]

have GUE changed the philosophy of scale-ability of system from rec to tech? If the diver is taught to go on a donated reg in the event of freeflow at the rec level, won't they also go to do so at cave/tech? That would be a very poor approach. We don't isolate a free flow reg and go to a donated long hose, we dive our gas on us until we have none. Mind you it's been 16 years since I did any GUE stuff...

At the fundamentals level 'troubleshooting' isn't really taught at all.

At the tech and cave level it absolutely is, though. You can shut down a reg and stay on your own gas supply, as you suggest, or work to fix whatever is leaking and carry on with the dive if it's fixable.

 

[Colliam7]

For the free flow exercises, both shops instructed him to take the free flowing regulator out of his mouth and "sip" the air (which he had some trouble with and kept getting water).
After the confined water, I told him the correct procedure was to keep the reg in his mouth, grab his pressure gauge, and begin to ascend with his buddy breathing normally; or signal his buddy, go on his buddy's reg and begin to ascend. (I didn't cover the other options such as turning tank valve off, etc. Just very basic, dives over, ascend with buddy) But then the checkout dives instructor had him do the same exact thing, sipping air. Is this a PADI standard of some kind? . . . Do any other agencies/instructors actively teach this? How is it better/safer than keeping the reg in your mouth?

This post raises some interesting questions, and has promoted good discussion. The diver that the OP encountered was taught a method that is probably used by the majority of PADI Instructors, and quite probably a large number of Instructors across multiple agencies. It has been taught in PADI OW courses for at least 15 years. BUT, it is NOT a standard, per se. The specific performance requirement is, '7. Breathe effectively from a simulated freeflowing regulator for at least 30 seconds.' Obviously, there may be several approaches to meeting that standard. However, the description of 'how' to teach the skill, provided in the PADI Guide to Teaching (GTT), is 'Have student divers practice breathing from a simulated freeflowing regulator for at least 30 seconds. Stress that divers should not seal their lips around the mouthpiece. Divers can use their tongues as splash guards to prevent choking on water. It may help to turn the head to one side so that the air rushing to the surface avoids jostling or dislodging the mask.' So, even though the performance standard does not specifically preclude keeping the reg in the diver's mouth, the 'not seal their lips' statement in the GTT effectively does. (It would be hard to exert the necessary back-pressure, to route the air flow out the exhaust T, with sealing the lips around the mouthpiece. The recommended method in PADI instruction is to 'sip' air. It is actually not a particularly hard skill to master. I have never had an OW student fail to learn to perform the skill competently. The 'sipping' approach addresses two concerns: possible a) lung hyperexpansion and b) significant gastric distention from swallowing a large volume of air.

The skill is performed with the purge button fully depressed. In that situation, keeping the reg out of the mouth is reasonable to avoid the two consequences. Now, I agree with the OP, that keeping the reg in the diver's mouth will work, and simply applying slight positive back-pressure will route the excess air out of the exhaust T. I have dove a slightly freeflowing second stage by keeping the second stage in my mouth, without issue. But, that is in a situation where the 'freeflow' is limited bubbling, not a full freeflow. From my perspective, having a reg fully freeflowing into a diver's mouth, could be challenging when the diver has to take a breath. Therefore, I would not agree that keeping the reg in the mouth is necessarily the 'correct' procedure. But, it is one alternative.

As for other methods: 1. Learning to breath from a freeflowing reg by feathering the valve is a great idea and skill. But, I do not believe that attempting to feather a back-mounted single cylinder valve is practical for a new(er) diver, and would add significantly to task-loading, with possible adverse consequences. In a sidemount configuration it is a much easier skill to teach (and I include that in my course, although it is not a standard, or a performance requirement). But, in a SM configuration, the (even) easier approach is to shut the valve entirely and end the dive. 2. Manipulating (bending) the second stage hose to staunch the flow also works, better for slight freeflows associated with IP issues than for full freeflows.