Am I too afraid of lung barotrauma? Remedies/Techniques?

[rob.mwpropane]

This assumption is NOT correct. There is NO CESA exercise in ANY course beyond OW, in ANY agency I am aware of, at any level through Advanced Trimix and Rebreather. So stop worrying about it.

Agree, my AOW in 2017 did not require a CESA.

 

[seeker242]

Actually it was just an uneducated guess, that if you would get the "Deep" Specialty and later on the Rescue Diver, the curriculum would have something like a CESA or EBA (if EBA is even taught anymore) to exercise from a depth deeper than in the OW Course.
I only found vague descriptions like "self rescue" in the rescue diver course descriptions.

Thank you for your tip by the way.

It's not part of either class.

 

[boulderjohn]

I was once trying to find some history of CESA, and I searched the Rubicon repository. I tried several different keywords and found different articles each time. What I learned was that in the 1970s, there was essentially a world-wide search for the best way to teach emergency ascents. Different places had different procedures, and people were publishing their ideas and experiments. Reading through them, you can see the gradual evolution of modern practices. I did not do more than read the articles as I browsed, but I think it would be fascinating to do a thorough search and write a history of how we got where we are today.

One of the related modern practices for which I found the beginning was the air depletion exercise, where the student's air is shut off prior to an OOA exercise. It started well before the invention of the alternate air regulator. Evidently in those days regulators on valves that had been shut off would become harder to breathe before stopping air flow entirely, and this was supposed to simulate the way a regulator gets harder to breathe as you get near the end of the air supply. The idea was that the diver would learn to recognize this and begin to take action. Regulators today do not do that, and when you turn off the valve, there is no such warning that you are near the end of your supply, the way there is when you run low on air. Thus, the air depletion exercise is a relic of past instruction that serves no purpose now.

 

[John C. Ratliff]

The Controlled Emergency Swimming Ascent has been with SCUBA diving since the beginning. The first recorded one that I am aware of was written be J.Y. Cousteau in his original book, The Silent World. On page 179-180 of the original hard cover version, Cousteau wrote,

...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...

...By this time the scholars realize they are learning by example. They remove their diving equipment entirely, put it back 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 ofthe course the honor students swim down to a hundred feet, remove all equipment 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 o bubbles from puckered lips...
Cousteau, J.Y., with Frédéric Dumas, The Silent World, Harper &Brothers Publishers, New York, 1953, pages 179-180.

So the CESA has been a part of diving since the very beginnings. It appears that this originated from perhaps the first scuba instructor, Frédéric Dumas, in the French Navy.

SeaRat

 

[Sam Miller III]

I will always recall the LA Co motto "Blow and Go; Flair and you are There !" --
~~~~~~~~~~~~~~
@SeaRat

Stated:
"The Controlled Emergency Swimming Ascent has been with SCUBA diving since the beginning. The first recorded one that I am aware of was written be J.Y. Cousteau in his original book, The Silent World. On page 179-180 of the original hard cover version, Cousteau wrote,
...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...

...By this time the scholars realize they are learning by example. They remove their diving equipment entirely, put it back 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 ofthe course the honor students swim down to a hundred feet, remove all equipment 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 o bubbles from puckered lips...
Cousteau, J.Y., with Frédéric Dumas, The Silent World, Harper &Brothers Publishers, New York, 1953, pages 179-180.
Click to expand...
So the CESA has been a part of diving since the very beginnings. It appears that this originated from perhaps the first scuba instructor, Frédéric Dumas, in the French Navy.

SeaRat"

I applaud your for researching and posting the event that occurred in the beginning of recreational diving
You have become my new best friend amd SCUBA Board Hero

I also did a fast review of my posts front several years ago on free assents

FYI

In the beginning in 1954 there was one certifying organization that was the very demanding LA Co UW Instructors Association who created the world's first certifying program, the Underwater Instructor's Certifying Course commonly referred to as "UICC"

The course required a D&R at 33 plus feet and a free assent (aka CESA) from 100 feet.. Every one who passed the course performed a CSEA with out any problems.

"Practice to perfection under controlled conditions what you may need to do under emergency panic conditions" was amd is still the theme

In1967 LA County developed the world's first Advance Diver Program the three months long "ADP. " It require the student to perform a free assent a "CESA" from 33 feet.

The program also required the students to maintain a LA Co dive log - the first time a dive log was required and it was the second dive log ever created-- The first Dive Log was created by the late Dick Bonin in 1955 while employed at the Chicago based company Dive Master, and who later founded SCUBA Pro in 1963- Lets give credit were credit is do...

Dick as an USN officer under Doug Fane { (read his book The Naked Warriors or view the movie - Underwater Warriors. Zale Parry (@Dr bill s close friend ) portrayed Doug's daughter) } In early 1950 Dick under the direction of Doug Fane was testing regulator performance under the artic ice for the USN. Dick's regulator froze - he made a free assent under ice from 200 + feet..totally out of air

Every diver I certified in 28 years of instruction as LA Co, NAUI, PADI CMAS and other certifications all did a 33 CSEA as part of Catalina dive experience. Not one had difficulty.

While training and diving with my young son, what seems like in retrospect every day and night, I made a rule that he could only dive as deep as he could perform a free assent CESA. I rescinded the requirement at 66 feet -As an adult pre med student Sam IV and Jeff Bozanic were drilling 300 & 400 foot holes in the Pacific -Good training pays !

Now he is practicing doctor and the director of the ER/Hyperbaric department at a local regional hospital

I have made innumerable free assents CESAs from 100 and one from, GOK, how many feet ? when my regulator and lift bag became one and I was totally and positivity out of air ! So away I went all tangled and dangled blowing and going to the surface... And I am alive and replying to this thread

Once perfected with perfect practice under controlled conditions and even more practice !
CESAs should be an automatic reflex , not a panic life threating or at worse case a fatal event in diving

In reviewing all the post I find it interesting how many people dive but so few who are divers

SeaRat keep up the good work and great well documented posts devoid of suppositions

Sam Miller, 111

 

[John C. Ratliff]

I was once trying to find some history of CESA, and I searched the Rubicon repository. I tried several different keywords and found different articles each time. What I learned was that in the 1970s, there was essentially a world-wide search for the best way to teach emergency ascents. Different places had different procedures, and people were publishing their ideas and experiments. Reading through them, you can see the gradual evolution of modern practices. I did not do more than read the articles as I browsed, but I think it would be fascinating to do a thorough search and write a history of how we got where we are today.

One of the related modern practices for which I found the beginning was the air depletion exercise, where the student's air is shut off prior to an OOA exercise. It started well before the invention of the alternate air regulator. Evidently in those days regulators on valves that had been shut off would become harder to breathe before stopping air flow entirely, and this was supposed to simulate the way a regulator gets harder to breathe as you get near the end of the air supply. The idea was that the diver would learn to recognize this and begin to take action. Regulators today do not do that, and when you turn off the valve, there is no such warning that you are near the end of your supply, the way there is when you run low on air. Thus, the air depletion exercise is a relic of past instruction that serves no purpose now.[/QUOTE]

John,

I have enjoyed your posts and knowledge in the past, but am having a hard time with the highlighted paragraph. I became a NAUI Instructor in 1973, and I cannot recall an "air depletion exercise" being conducted as part of a NAUI course. Maybe others could enlighten us about that.

Concerning regulators and air being turned off, the old time regulators were either double hose or single hose regulators without SPGs. When the valve is turned off, there is only about one breath until completely OOA. In contrast, today's modern regulators, with an octopus, a LP inflators hose, and a SPG have about three breaths after the valve is closed completely due to the increased volume inside the regulator of low pressure air.

Now, about older designs having more warning for potential out-of-air situations--it depends. For an unbalanced two stage regulator (Aquamaster, Conshelf I-III, Sportsways Sport Diver) with diaphragm design, they actually go at easier to breath as tank pressure went down, as interstage pressure went up with that design. But the piston unbalanced designs would experience slightly increased breathing resistance as the tank pressure decreased as there apwas a corresponding decrease in interstage pressure. For the single stage double hose regulators, with an upstream valve design, breathing became much, much easier around 500 psig. The Mistral was a dream to breath at 500 ps, and I knew the tank pressure was getting low when it breathed so easily.

Because of this, Healthways, in their double hose regulators, and their single hose Scuba Star and Scubair regulators had what they called a "Positive Air Reserve" option. When you bought the regulator, you specified whether it was being used with or without a J-valve. This was either a disc with a very small hole incerted in-line with the sintered filter, or a setting (Scubair, which could be set for either J-valve use or positive reserve) which restricted the air flowing to the regulator at lower tank pressures. I grew up with this reserve (my first two preglators were a Healthways original Scuba double hose, and then a Healthways Scuba Star single hose regulators). I now have a collection of Healthways regulators, and a few years back took my Scubair into the Clackamas River to find out when I couldn't first detect this restrictor reserve action. I surfaced as soon as I felt it, and swrched to my snorkel. As this regulator did not have an SPG attached, I wanted to know the tank pressure from a gauge after getting out of the water. As I recall,it was around 600 psig. This reserve was great for open water, but not so great if the diver had to go deeper to get to where he or she could surface (wreck and cave diving), as it would get much harder to breath with depth. This reserve literally forced a diver to the surface.

Now, I can remember only one time I used a CESA in over 50 years of diving. I was working for the Oregon Department of Fish and Wildlife, on an underwater clam bed survey. On this dive, which was the last of the day on a depleted tank, I wanted to photograph the divers dredging for clams with my Nikonos underwater camera. I think we were in about 30 feet of water, and I hadn't gotten the photos I wanted when my tank went dry (no air). So I Buddy breathed with one diver, them mover away to get the photos, came backed and had one more Buddy bepreathing session, then ascended to the surface using a CESA. I think I still have the Description in my dive log (I'll look). At the time, I didn't think much of it. Actually, I believe I remember one more CESA, and that was from about the same depth in Yaquina Bay when I was first certified LA County by Roy France. We had to do one with him holding my shoulder strap for our checkout dive in 1963. (I had been diving without certification since 1959, as there were no diving instructors in Salem, Oregon at the time; we had to import Roy from California.)

SeaRa[/QUOTE]

 

[boulderjohn]

I have enjoyed your posts and knowledge in the past, but am having a hard time with the highlighted oaragraph. I became a NAUI Instructor in 1973, and I cannot recall an "air depletion exercise" being conducted as part of a NAUI course. Maybe others could enlighten us about that.

It has been required for PADI since well before I was an instructor. We had a thread a couple of years ago in which someone posted the PADI standards from 30 years ago, and it was there then. For PADI, it is required twice in the pool sessions. The first time, the student is to signal OOA, and the air is turned on. In the second, the student signals OOA and goes to a buddy for an alternate air source.

I first became puzzled about the practice as a DM assisting classes. PADI instructional practices require instructors to tell students why they are doing an exercise before it is done, and the standard explanation was that you were getting to experience the greater difficulty of breathing when a tank is getting low, and students were to signal OOA when they felt that greater difficulty. After that, whatever instructor I was working with would demonstrate with me as the OOA diver. I did this many times, and I never felt the slightest increase in difficulty breathing before I was abruptly out of air. In contrast, I have breathed scuba tanks down many times, and I have always felt the increased difficulty. I have done it at depth breathing a stage down before switching to back gas, and I could feel the increased difficulty long before the tank was OOA. I have mostly felt it above water, because when I drive home over a mountain pass after diving, I breathe from my used oxygen deco bottle to lower nitrogen tissue pressure, and I sometimes take it all the way to empty. When I do, I get plenty of warning from increased difficulty in breathing.

As for 1973 NAUI standards, as I wrote, the articles I was reading were written in the 1970s, and it is quite possible that the article that I found suggesting the practice came after 1973.

 

[tursiops]

So, as we descend, the volume in the tank decreases.....As, we ascend the volume in the tank increases

?? I think you meant to say something else. The volume of air in the tank is constant, and not a function of depth.

 

[boulderjohn]

o, as we descend, the volume in the tank decreases.....As, we ascend the volume in the tank increases.

I didn't notice this. As Tursiops said, the volume in the tank does not change, but it is a very common misunderstanding. Very recently a very renowned and knowledgeable tech instructor said the same thing.

The air inside a tank does not respond to changes in external pressure because it is in an inflexible container. What does respond to external pressure is the regulator first stage. It must be able to deliver air to you at a pressure a little greater than ambient pressure, or you cannot breathe. To do this, the regulator is designed to react to that pressure, with the external pressure assisting the regulator so that it can maintain that required level of pressure.

As a tank reaches its near-empty point, it does not have enough pressure to deliver the air as it did before, and the diver must inhale harder to get the air. If a CESA is to be done, that is the best time to do it. If you wait longer, the air flow will stop. As you ascend while doing a CESA, the water pressure around you drops, and eventually it reaches the point that the regulator can once again give you some air. Although I have never tried it, it is possible that if you were to begin a normal ascent at the first sign of difficulty inhaling, you could breathe normally all the way to the surface and not have to do a CESA.

 

[John C. Ratliff]

Boulder John,

I have just reviewed my NAUI course standards and stand corrected. For "BASIC SCUBA DIVING COURSE STANDARDS," NAUI stated:

d). Open Water Skin and Scuba Diving

1). Perform without stress: water entries/exits, surface dives, buoyancy control and surface, Underwater and survival swimming with both skin and Scuba equipment.

2). Make a complete rescue of a buddy diver.

3). With scuba equipment: clear mask and mouthpiece, Buddy breathe, alternate between snorkel and Scuba and make a controlled emergency swimming ascent.
Page 2.1d-3
8/75

The CESA I described above happened on Sept. 15, 1975, with Buddy divers Tom Gaumer and Limens Osis, from 39 feet. Here's my note on this dive:

photography Dives--Ran out of air on last dive. Buddy breathed ~5 min--long enough to get the photos needed.

I didn't even mention the CESA, as that didn't seem extaordinary to me at the time.

SeaRat