Water in regulator at depth causing panic

[Celt]

When my brother and I got our hands on a Spiro 72cu/ft. tank and Spiro Aqualung reg we regularly shared it on our spear fishing trips out to 50feet along the coast. We’d breathe it completely empty and simply surface. Look up, open your mouth and head for the surface is all needs to be done in anything shallow. Deep is another thing altogether, I made a CESA for 140 feet long before BCD,s or backup regs. If you’re not going FAST you won’t make it. There’s another thing about modern regs, they don’t warn you that you’re running low. There’s a bit of suck to the old regs.

 

[OMyMyOHellYes]

Engaging vocal cords for audible confirmation (and control) of exhalation vs not engaging vocal cords in a stream of air from the lungs: I fail to see any physiological difference. If you can imagine one, please explain.

As a matter of reference, PADI codifies the "Ahhhh" or hum (as I was taught in the OW course) as part of the CESA Procedure:

"During Confined Water Dive Three you will practice the Controlled Emergency Swimming Ascent.

• In a real emergency, you would swim to the surface. To cover the same distance in confined water, your instructor will have you practice the skill swimming horizontally.
• Imagine moving vertically, and that ahead of you is up.
• Reach out holding your BCD deflator and look ahead (in the position that would have you reaching up and looking up if you were vertical, swimming up to the surface).
• Your instructor will be beneath you, face up, or beside you, holding on to your BCD.
• On your instructor’s signal, take a breath and exhale it continuously making a loud “ahhhhh” sound as you swim no faster than 18 metres/60 feet per minute for at least 9 metres/30 feet (a 30-second swim).
• Keep all your equipment in place.
• By making an “ahhhhhh” sound, you should be able to complete the swim in a single breath."

From PADI eLearning, Open Water Diver, Your Skills as a Diver III, Topic 7 of 10

Also -
"Option 3: Make a Controlled Emergency Swimming Ascent (sometimes called CESA).

• This is the best choice if you were completely out of air, no deeper than approximately 6 to 9 metres/20 to 30 feet, the surface is closer than your buddy(ies) or another diver, and you have no other alternate air source.
• Simply look up and swim to the surface making a continuous “ahhhhh” sound into your regulator. The “ahhhhh” sound assures that you exhale expanding gas, which is necessary to avoid lung overexpansion injury.
• Leave all your gear in place and keep the regulator in your mouth. Do not drop your weights to start your ascent.
• Ascend at a safe rate. The ascent gets easier as you ascend because air expanding in your BCD increases your buoyancy. Vent air as needed to maintain a proper rate."

"Option 4: Make a buoyant emergency ascent.

• Use this option when you are too far from your buddy(ies) or another diver, have no other alternate air source and are so deep that you doubt you can reach the surface any other way.
• You make a buoyant emergency ascent exactly like a Controlled Emergency Swimming Ascent, except you ditch your weights and exceed a safe rate."

From PADI eLearning, Open Water Diver, Underwater Problem Management, Topic 4 of 5

 

[FishWatcher747]

On your instructor’s signal, take a breath and exhale it continuously making a loud “ahhhhh” sound as you swim no faster than 18 metres/60 feet per minute for at least 9 metres/30 feet (a 30-second swim).

I just did this exercise sitting down in my house with no stress as one would have in training or a real CESA.

After 20 seconds of making the "Ah" sound no more "Ah" was happening, no sound. Just like Juice Newton holding a note for 20 seconds, not 30 seconds.

More accurate to say, make the "Ah" for as long as you can then keep your airway open for the rest of the 30 second exercise, or completion of a real CESA.

 

[lowwall]

I just did this exercise sitting down in my house with no stress as one would have in training or a real CESA.

After 20 seconds of making the "Ah" sound no more "Ah" was happening, no sound. Just like Juice Newton holding a note for 20 seconds, not 30 seconds.

More accurate to say, make the "Ah" for as long as you can then keep your airway open for the rest of the 30 second exercise, or completion of a real CESA.

It seems like you are missing the very important point that in a real CESA, the residual gas in your lungs expands as you ascend. 20 seconds of ahhs at the surface equals around 40-60 seconds of aahhs on an ascent from say 60-100 feet.

 

[FishWatcher747]

It seems like you are missing the very important point that in a real CESA, the residual gas in your lungs expands as you ascend. 20 seconds of ahhs at the surface equals around 40-60 seconds of aahhs on an ascent from say 60-100 feet.

I get that. In my description of doing my training CESA from 25 feet I hummed for 10 seconds until I fully exhaled then after a pause of maybe 10 seconds I was able to restart humming audibly because of expanding gas.

Why not explain to the students that if you get to the point of a full exhale during the CESA you will either momentarily be unable to make the hum or Ah sound but as air expands you may be able to continue to do so and to keep your airway open?

For a 30 second horizontal swim simulating a CESA this is even more important as once a student fully exhales there is no expanding air to continue to make the Ah or hum noise.

Sitting at your computer, how long can you make the "Ah" sound on one exhale?

 

[boulderjohn]

One of the key concepts in the theory of effective instruction in a performance skill is to have the student perform the skill in practice as nearly like the way it will be done in real life as possible. I used to teach this concept to teachers--I could fill my character limit on this post with examples of how having students practice something differently from the way they will do it in a real event teaches incorrect skills. Making an audible "aaahhh" is an example.

The purpose of the "aahh" is to let the instructor know that the diver is exhaling. In a real life CESA, it won't matter that much, but there is obviously no reason for it. Where it really matters is in the horizontal CESA in the pool. Making an audible "aaahh" makes it close to impossible. When I was a DM, I demonstrated the horizontal CESA for an anal instructor who insisted that the 30 feet had to be done in 30 seconds, and I could not possibly do it with an audible "aaahh." I always did it with an "aaahhh" that sounded more like a slight croak that could not possibly be heard by anyone, and that is what that instructor told the students to do.

So what's wrong with that?

We are teaching students that they can't do it. We are teaching them that if they ever get in a real situation, they had better hold their breath.

 

[FishWatcher747]

We are teaching students that they can't do it. We are teaching them that if they ever get in a real situation, they had better hold their breath.

I am guessing that Juice Newton, BoulderJohn and I are not far from the mean in being unable to make an audible "Ah" for 30 seconds.

So all of those people around the mean come away from confined water thinking they are a total failure at one essential skill required for scuba diving. That is making an audible "Ah" for 30 seconds during a horizontal swim.

It might be way better to inform these students that once you fully exhale during a CESA to just keep your airway open.

How about reassuring students in the following way. The adult lung capacity is 6 liters. Forced lung capacity, the amount of air one can exhale is 80% or 4.8 liters. Residual volume is 1.2 liters after a full exhale. If one CESAs from 66 ft, 20 meters, fully exhales to 1.2 liters, that volume will triple when you get to the surface or 3.6 liters. If your lung capacity is 6 liters, 3.6 liters of air in your lungs is not going to harm you.

 

[boulderjohn]

It might be way better to inform these students that once you fully exhale during a CESA to just keep your airway open.

If you are exhaling at a reasonable rate in a real CESA, you will never run out of exhaling air.

Look at the old US Navy submarine escape videos. They exhale fully before beginning the ascent, begin exhaling again right away, and exhale all the way to the surface. They are doing a buoyant ascent rather than a CESA, but that's OK for a diver to do from greater depths, too.

 

[FishWatcher747]

How about reassuring students in the following way. The adult lung capacity is 6 liters. Forced lung capacity, the amount of air one can exhale is 80% or 4.8 liters. Residual volume is 1.2 liters after a full exhale. If one CESAs from 66 ft, 20 meters, fully exhales to 1.2 liters, that volume will triple when you get to the surface or 3.6 liters. If your lung capacity is 6 liters, 3.6 liters of air in your lungs is not going to harm you.

It might also be reassuring to students to know in the example above if one had to do a CESA from 130 ft, 40 meters the recreational limit for scuba diving for some training agencies, fully exhaled from 6 liters of lung volume to residual volume of 1.2 liters, the gas would expand 5 times to 6 liters or your original full lung capacity when you get to the surface.

Don't try this at home, keep exhaling.

 

[OMyMyOHellYes]

Don't try this at home, keep exhaling.

Or just say "Aahhhhh" into your second the whole way.