Water in regulator at depth causing panic

[BoltSnap]

One of the advantages of being an older diver and diving for a while is that we used to carry a snorkel on our mask, and do a lot of surface snorkeling to the dive site from shore.

I must be very old, that's all I do and enjoy very much. I usually surface swim with snorkel for a long distance to get to deeper water. My average swim out is around 500m. Distance depends on wetsuit thickness and air and water temperatures and sea state. Never dive without snorkel except for when diving inside wrecks.

I teach fair amount of skin diving skills in my openwater scuba diver course in pool and in open water training in addition to the scuba skills. My students have to do a 1km surface swim with snorkel in pool and in open water training.

 

[Litefoot]

I have done some CESAs (controlled emergency swimming ascents) from about 33 feet, and don't recall any sensation of wanting to inhale. Mostly, there is excess air and so there is a need to keep the airway open and mouth open so as to exhale that excess air during the CESA. I have not done that from deeper water, nor for an extended time period. But again, there was no sensation of needing to inhale.

Now, I'm pretty familiar with swimming and diving, even in my early days. I was on swim teams before diving while a young teen, and it was a water person. So someone who was not a water person may have different experiences.

SeaRat

The reality is that the trading agencies have deemed a true cesa too dangerous, primarily because of the danger of over expansion. You can swim or float up very fast if healthy and airway is open. In a real situation, the diver is going to be under a lot of stress and will probably be moving pretty fast- suggesting ascent rates has limited utility, but if you are doing one of these and you reach maybe 25 feet and feel fine, it would make sense to really slow the ascent.

I'm not sure I understand the question, or at least its premise. I have never done a real CESA, but I have talked to some who have, and the urge to breathe was not an issue for them.

When I was certified as an instructor, we were told to have students use a "normal" rate of ascent. Back than, that was 60 FPM. When I took the exam, the instructor examiner stressed that it was plenty OK for students to exceed that rate. Your goal is to get to the surface, not do some sightseeing on the way up.

Boulderjohn. it was a question without real-world application. As you and others alluded, ascent rates in a real CESA will not be slow, so there will always be expanding air volume leaving the lungs.

 

[John C. Ratliff]

Okay, I see where this is going. Let me explain about one of my CESAs. I was a diving technician for the Oregon Department of Fish and Wildlife (ODFW). I was photographing the work of clam bed surveys, where we dredged a 3 square foot circle and recovered all the clams in that site, down to about 3 feet depth in the bottom. On these dives, I was photographing the work. On the second dive I dove to 37 feet, and ran out of air before I had finished the photography (ran out of film). I wanted to get a few more photos, so I stayed down buddy breathing with Tome and Limons until I had the last photos. Below is the 9-15-75 dive log for those dives. When I finally did run out of film, I signaled Tom and Limons that I was surfacing, and swam up to the surface where our boat was anchored. This was a a CESA from about 30 feet. I did not swim hard or fast to the surface, as that wasn't necessary. I had a good lungful of air from one of the other two divers, and swimming 30 feet underwater was something I could do in my sleep, horizontally or vertically (obviously, a figure of speech). Anyway, I was comfortable doing this. Obviously, I exhaled air all the way up. And, it was easy. To me it wasn't actually an emergency.

Now, the way we teach, the way we now accept people for diving who really aren't "water people" is contributing to the thoughts of panic that I see in the posts above. I had been through some extreme schools, LA County Basic Scuba in 1963, U.S. Naval School for Underwater Swimmers in 1967, the U.S. Air Force Pararescue Transition School in 1967, and NAUI ITC in 1973. I was (and am) extremely comfortable in the water, in situations that others may not be. But we are not now sending people through experiences like I got in training, and are telling people that they will die if they run out of air. That is only true if they are technical divers (cannot swim to the surface for overhead situations, or because of incurred decompression obligations). For sport diver, a CESA is not at all hard, if they are trained and prepared.

A few years ago, I practiced a CESA of a simulated 75 feet, in a pool that was 16 feet deep, by starting in the deep end, and with an exhalation (simulating a regulator failure) made the CESA by swimming up, exhaling some air all the way (we do have residual air in our lungs, even upon exhalation), and horizontally for 25 yards (simulating a CESA of 75 feet). I did not swim fast, but used a normal swimming speed to make it 25 yards, easily. I don't know why this is being taught as such an exceptional thing to be able to do?

SeaRat

 

[jhawn518]

This is fantastic news...

• You've learned so much in one dive.
• You've learned about how incipit panic is; underwater it's so dangerous as you simply cannot do what the panic wants, you need your logical brain not the "chimp" brain.
• You've learned about regulators and failures. Can happen any time, but the rental kit is often cheap and very well used so may well fail.
• You've thought through switching regulators underwater meaning that the "octopus" is actually as much for you as any other diver. Hopefully you'll use it every time on every dive.
• You've had reminders about using the purge button to get a free-flow of gas, both to purge the mouthpiece, but also to work around leaks

And you didn't panic, you didn't die, you resolved the issue. A great learning experience which will make your future diving so much better.

Look on the glass half full side. Of course all sorts of things could have happened. They didn't and why should they. Generally only one thing fails; it's the reaction to that failure which determines the outcome.

I second this perspective enthusiastically.

 

[boulderjohn]

But we are not now sending people through experiences like I got in training, and are telling people that they will die if they run out of air. That is only true if they are technical divers (cannot swim to the surface for overhead situations, or because of incurred decompression obligations). For sport diver, a CESA is not at all hard, if they are trained and prepared.

I have written about this repeatedly over more than a dozen years on ScubaBoard. I believe the way the CESA is traditionally taught leads to this belief that it won't work in a real life situation, and that in turn leads to panic when that situation arises in real life. That panic leads divers to hold their breaths during a sprint to the surface. A joint PADI/DAN study about a decade ago determined that the number one training-related cause of death in scuba is an air embolism following a panicked sprint to the surface--in other words, an improperly performed CESA.

It would take a while for me to list all the things wrong with the way we teach it, but the primary one is the 30-foot horizontal CESA in the pool. Although my examiner when I was certified emphasized it was OK to go more than 60 FPM, all the instructors I worked with when I was an assistant insisted on it, and it would take many tries for students to be able to exhale for 30 seconds. This leads to the belief that if it is that hard to do it for 30 feet, then it will be impossible to do it any deeper than that. Their horizontal experience in the pool contradicts what they are told about the benefits and dangers of the expanding air on a vertical ascent.

ScubaBoard does not help at all. Whenever one of the many threads on this appears, people jump in to emphasize the importance of being able to hold one's breath for extended periods of time in order to be safe during a CESA. The ability to hold your breath is meaningless on a CESA, since you will be exhaling the whole way. The US Navy trains escaping submariners to exhale fully before they begin their ascents.

See Post #61 in this thread.

Although I have never done it, if I were to run into an unimaginable situation at 100 feet, I would CESA without a concern.

 

[boulderjohn]

and are telling people that they will die if they run out of air.

I wanted to make this point separately.

One of the positions I have argued against strenuously in past ScubaBoard debates is the belief that training should emphasize that running out of air on scuba without a buddy inches away is a death sentence. The belief is that if this message is transmitted well enough, divers will be more careful about monitoring their air and staying close to a buddy.

 

[L13]

ScubaBoard does not help at all. Whenever one of the many threads on this appears, people jump in to emphasize the importance of being able to hold one's breath for extended periods of time in order to be safe during a CESA. The ability to hold your breath is meaningless on a CESA, since you will be exhaling the whole way. The US Navy trains escaping submariners to exhale fully before they begin their ascents.

I wanted to emphasize this!

I was personally trained by the US Navy to do this.

 

[OMyMyOHellYes]

One of the positions I have argued against strenuously in past ScubaBoard debates is the belief that training should emphasize that running out of air on scuba without a buddy inches away is a death sentence. The belief is that if this message is transmitted well enough, divers will be more careful about monitoring their air and staying close to a buddy.

See Post #61 in this thread.

This seems, to me, to be a lot like spin training in flight training, no longer required except for instructor training.

Yes, both the captain and copilot on any flight you are on may never have been taught to recover from a spin - a very simple, basic maneuver - pull off any power, center the ailerons, stop rotation by application of the rudder and when you quit turning, briskly push the yoke forward to break the stall, build speed and recover.) And many pilots are deathly afraid of spins to the point of assuming spin = death. Because that's what has been taught for the last 50 years.

Spins are not scary. They are fun. I have, on occasion, climbed a C-152 to 10,000' (long ride), pulled out the throttle, carb heat, and pulled the yoke back to the stall and then stomped rudder to break into a spin and rode it all the way down to 1,500 ft. I've done the same thing just not stomping rudder, but dancing to keep the ball centered and just rode the stall down to 1,500 and recovered (that is a great rudder exercise and can teach a student much about using the pedals...)

Spins are not hard, but some folks died while doing them poorly in training - or real life - so they quit teaching them pretty much altogether.

Sounds a lot like the approach to teaching proper CESAs.

 

[Litefoot]

This seems, to me, to be a lot like spin training in flight training, no longer required except for instructor training.

Yes, both the captain and copilot on any flight you are on may never have been taught to recover from a spin - a very simple, basic maneuver - pull off any power, center the ailerons, stop rotation by application of the rudder and when you quit turning, briskly push the yoke forward to break the stall, build speed and recover.) And many pilots are deathly afraid of spins to the point of assuming spin = death. Because that's what has been taught for the last 50 years.

Spins are not scary. They are fun. I have, on occasion, climbed a C-152 to 10,000' (long ride), pulled out the throttle, carb heat, and pulled the yoke back to the stall and then stomped rudder to break into a spin and rode it all the way down to 1,500 ft. I've done the same thing just not stomping rudder, but dancing to keep the ball centered and just rode the stall down to 1,500 and recovered (that is a great rudder exercise and can teach a student much about using the pedals...)

Spins are not hard, but some folks died while doing them poorly in training - or real life - so they quit teaching them pretty much altogether.

Sounds a lot like the approach to teaching proper CESAs.

Probably wasn’t much fun cleaning the stains off the right seat, though.

 

[John C. Ratliff]

As you said repeatedly throughout the reset of the thread, you did not actually say that a diver should hold the breath during the ascent, but that is what most people would infer from what you wrote. I sure did, and that is after rereading it after your strongly worded attacks on the reading ability of those who said you did.

A joint DAN/PADI study on dive fatalities found that an air embolism following a rapid ascent to the surface (with the diver obviously holding the breath) is the number one incident-related reason for dive fatalities. That is why I am so obsessed with two things I see repeated over and over and over and over on ScubaBoard (including this thread):

• It would be really hard to get to the surface in an out of air emergency.
• Your ability to get to the surface in an out of air emergency depends upon your ability to hold your breath.

Here is the reality:

• Training for escape from submarines has had sailors successfully reach the surface from 300 feet, starting after they exhale first and then continuing to exhale all the way to the surface.
• If you are exhaling all the way to the surface, your ability to hold your breath has zero, nada, nil, nothing to do with your ability to get to the surface.
  (jcr: emphasis added and subtracted [the strikethrough is for incorrect concepts, as enunciated by BoulderJohn])

Okay, I'm replying to this post by BoulderJohn so as to bring this back to the discussion. I fully agree. Before doing that, I'd like to review with people this diagram from the U.S. Navy Diving Manual, March 1970. If you look at this Figure 1-24. Lung volume, you can see our normal "tidal volume" showing at about 0.5 liters. This is for normal breathing, which is what we teach for scuba diving. So if in my experiment I exhaled and could not inhale, the "expiratory reserve volume" still in my lungs is about 1 liter. I did my comparison from 75 feet, which is just over 3 atmospheres (66 feet, or 20 meters, is 3 atmospheres absolute pressure). What does this mean. Well, that 1 liter, upon ascending from that depth, will expand to over 4 liters of air by the time I reach the surface. Note that a normal person has a 4-5 liter vital capacity (mine is closer to 6 liters.) Actually, in my test in 16 feet of water, I did get expansion so as to never have a problem exhaling. Note that 4 liters is 8 times the amount of a normal breath, which like I said is what we teach divers to do while breathing.

I learned diving in 1959 from the book by J.Y. Cousteau titled The Silent World. I read that book probably 3 times when it was the only reference I had to learn diving physics and physiology. If you read that book, Cousteau introduces you to Archimedes Principle in the first chapter, when he states on page 4:

The diving lung was designedh to be slightly buoyant. I reclined in the chilly water to estimate my compliance with Archimedes' principle that a solid body immersed in liquid is buoyed up by a force equal to the weight of the liquid displaced. Dumas justified me with Archimedes by attaching seven pounds of lead to my belt. I sank gently to the sand. I breathed sweet effortless air. Tthere was a faint whistle when I inhaled and a light rippling sound of bubbles when I breathed out. The regulator was adjusting pressure precisely to my needs...(page 4-5)

Cousteau introduced me to much of my understanding of physics and physiology as a 13 year-old boy. The same is true of his discussion of pressure, and he explained the way that Frédérick Dumas trained the first French divers to train on the aqualung.

...Dumas planned the diving courses for the fleet aqualung divers, two of whom are to be carried on each French naval vessel. He immerses the novices first in shallow water to bring them through the fetal stage that took us years--that of seeing through the clear window of the mask, experiencing the ease of automatic breathing, and learning that useless motion is the enemy of undersea swimming. On his second dive the trainee descends fifty feet on a rope and returns, getting a sense of pressure change and testing his ears. The instructor startles the class with the third lesson. The students go down with heavy weights and sit on the floor fifty feet down. The teacher remoses his mask and passes it around the circle. He molds the mask again, full of water. One strong nasal exhalation blows all the water through the flanges of the mask. Then he bids the novices emulate him. They learn that it is easy to stop off their nasal passages while the mask is off and breathe as usual through the mouthgrip.

A subsequent lesson finds the class convened at the bottom and again their attendance is assured by weights. The professor removes his mask. Then he removes his mouthpiece, throws the breathing tube look back over his head and unbuckles the aqualung harness. He lays all his diving equipment on the sand and stands, naked except for his breechclout. With sure, unhurred gestures he resumes the equipment, blowing his mask and swallowing the cupful of water in the breathing tubes. The demonstration is not difficult for a person who can hold a lungful of air for a half minute.

By this time the scholars realize they are learning by example. They remove their diving equipment entirely, put itback on, and await the praise of the teacher. The next problem is that of removing all equipment and exchanging it among each other. People who do this gain confidence in their ability to live under the sea.

At the end of the course the honor students swim down to a hundred feet, remove all equypment and return to the surface naked. The baccalaureate is an enjoyable rite. As they soar with their original lungful, the air expands progressively in the journey through lessening pressures, issuing a continuous stream of bubbles from puckered lips...(JY Cousteau, with Frédéric Dumas, The Silent World, Harper & Brothers Publishers, New York, Copyright 1953, pages 179-80.)

Note that the original diving course, by Frédérick Dumas, involved a graduation by a relaxed swimming ascent without a dive lung from 100 feet (30.5 meters). I have no doubt that, at age 77, I could complete a CESA from the limit of sport diving, 130 feet (40 meters). "This baccalaureate is an enjoyable rite"! This is not an emergency ascent, but a controlled swimming ascent from 100 feet depth to the surface. From the description, it sounds like it was a relaxed swimming ascent without fins too! This is some of the history of scuba diving that has been lost for this generation of both students and instructors.

Again, this is for sport diving, without incurring a decompression obligation, and not being in an overhead environment (wreck, cave, under ice, etc.) diving.

SeaRat