Why extra air when solo?

[tursiops]

I had a failure to deliver air at 70' after I had exhaled. My "reg rebuilding buddy" was nowhere to be found. So up I went so scared I could barely think. I remember at 35FSW (a guess) I felt the need to exhale so I did the rest of the way to the surface.

You mean you held your breath and did not exhale from 70 to 35 ft?

 

[John C. Ratliff]

You mean you held your breath and did not exhale from 70 to 35 ft?

Probably, there was nothin' to exhale on this particular CESA until he got to around 35 feet, and the air in his initially almost empty lungs had expanded sufficiently to give him enough to exhale. Remember Boyle's Law?
Boyle's law - Wikipedia
SeaRat

 

[John C. Ratliff]

I find this rather humorous in that my first diving experiences, in 1959, were solo. I started diving in an era before dive shops (mine was a sporting goods store in Salem, Oregon) with used equipment I bought with strawberry and bean picking money I earned over the summer. I dived mostly rivers (the North Santiam River near Salem) and lakes in the Cascade Mountains near Bend, Oregon (Elk Lake). I dove when my family was fishing. And, I dove solo, without formal instruction (I read The Silent World, by Jacques Cousteau, three times). I remember one early dive out of my parent's seven-man life raft in Elk Lake, using my Healthways Scuba double hose regulator and a 38 cubic foot tank. I was probably 15 years old at the time. I was alone, and lovin' it. The bottom was covered with aquatic weeds, and a few trout were circling around, but not expressing any interest in the bait my parents were offering.

I finned around for probably about 20 minutes, then started up when breathing became harder (I was using a restricted orifice reserve, built into my Healthways Scuba regulator). But before I surfaced, my Grandmother, who was in the boat and very nervous about my being underwater, finally became agitated and told my Dad, "Tell him to come up! TELL HIM TO COME UP!"

My Dad simply turned to her and asked, "How?"

It was not until 1963, when we had hired a California scuba instructor named Roy France, that we got certified, LA County. Until then, I was sometimes diving with a buddy, sometimes solo before solo was known as a specialty. So, how did I, as a kid, survive?

Well, let's look at it from the standpoint of Dr. Stanley Miles' Accident Equation (published in his book, Underwater Medicine).

A = CE(prf/tms), where A = accident; C = Chance; E = Environment; p = accident proness; r = risk acceptance; f = physical factors; divided by the factor of t = training; m = maturity; and s = safety measures.

I had been a water kid since age six, on age-group swim teams from about age ten through high school into college, had gone through lifeguard training, and had become by high school a WSI, or Water Safety Instructor. Plugging these into the equation above from Dr. Miles, you can see that I was very high in the denominator of that equation, and dove lakes and rivers that were shallow and pretty tame (although the rivers did have currents and cold). I was also using a very, very simple Healthways Scuba regulator (six moving parts--one reason the Cousteau teams used the Mistral, which was similarly a six-moving-part scuba). The chances of a scuba unit malfunction at depth were minuscule. That simply left watermanship (now a pretty sexist statement) as a factor, and I was more than at ease in the water.

So when I see a specialty course in "solo diving," I chuckle a bit. What this course is set up for is those who are not especially comfortable diving, who must be equipment-dependent for their safety. Someone above mentioned a emergency swimming ascent (CESR) as not practical for depths beyond about 25 feet. If you've read The Silent World, you will understand that Frédéric Dumas, when he taught the first scuba courses in France, had his divers do a CESR from 100 feet.

...At the end of the course the honor students swim down to a hunderd feet, remove all equipment and return to the surface naked. Tthe 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....
Cousteau, Jacques, with Frédéric Dumas, The Silent World, Harper and Brothers Publishers, New York, 1953, page 180.

So today's students are very, very different from those at the beginning. Today's students are equipment-dependent because of their lack of water skills, and the types of instruction that they get. We don't require these divers to be proficient in the water, much less swim team members, to dive. That throws Dr. Miles' equation over toward needing things like redundent air. Today's regulators seem to be less reliable than those of yesteryear too. So we need redundant scuba to survive.

I am a safety professional (retired after over years in the occupational safety and health fields). Would I tell someone to solo dive without redundant air? No! Not in today's world. But I sometimes do that, even at age 73, I dive vintage gear sometimes in rather tame conditions (with lifeguards on the cliffs above). I also dive different configurations of gear. Two days ago, I dove solo with a twin 52 setup and my Mossback Mk 3 regulator (a modification of the DA Aquamaster that has a balanced first stage, with both LP and HP outlets), an octopus, dive computer, and LP inflator for my Para-Sea BC (my own invention--that's another story entirely).

What I've found is that the old gear that we used in the mid-1960s through 1990s was rather good gear, with fewer failure points, and easier access than today's gear. I read one poster above stating that he knew which regulator he was handling by feel, as each had a different LP fitting, and I wondered how that would work with thick neoprene diving gloves in cold water?

Here is one of my solo dives.

 

[AfterDark]

I asked the question of that poster because holding one's breath while ascending is a really bad idea. I hope he did NOT hold it, but rather just kept the airway open and (if Boyle's Law was the culprit) finally exhaled for real. He does not need to close his airway and "hold his breath" even if there is no air in his lungs. I wondered if he did, if he'd thought about it, and give him a chance to explain further. Don't you think that asking a question like this is nicer than saying, "You stupid idiot, don't hold your F****** breath!"

I didn't have any air to exhale so I didn't blow out. I kept my mouth open and my head back to let any expanding air purge on it's own. Until I felt a little air in my lungs again at about 35 feet, maybe it was 38 or 39 or maybe 42 I don't know for sure that was 1971 for Christ sake! You want me to recount a 45+ year old incident that lasted less than a minute and half. Let me know how that works out for you at 65 years old.
I was 18 years old with 2 years diving experience I was lucky to keep my head never mind remember details.

EDIT: I've been thinking about this incident since I posted about and I recalled something that I had forgotten when I posted, when I got to shore I had no weight belt. I don't remember releasing but it lies somewhere off Castle Hill Newport,RI in 200FSW. Castle Hill is a wall dive in that area I/we were somewhere around 70FSW but that had been the last time I looked at my gage. I/we could have been deeper by the time of the incident but I know for sure just prior I was at 70FSW.

It is dangerous to hold ones breath on ascent but , I'll tell what is just as dangerous, being at 70FSW in the dark cold water off Castle Hill, with no air no visible buddy and 130FSW below you. That is a situation you want to get yourself out of ASAP which is what I did with a lot of luck not much skill at the time but a lot of luck. Hard to kill.

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this post has been edited by removing last unnecessary paragraph

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[Bob DBF]

He does not need to close his airway and "hold his breath" even if there is no air in his lungs.

So when one holds their breath, they have to close their airway?


Bob

 

[chillyinCanada]

I find this rather humorous in that my first diving experiences, in 1959, were solo. I started diving in an era before dive shops (mine was a sporting goods store in Salem, Oregon) with used equipment I bought with strawberry and bean picking money I earned over the summer. I dived mostly rivers (the North Santiam River near Salem) and lakes in the Cascade Mountains near Bend, Oregon (Elk Lake). I dove when my family was fishing. And, I dove solo, without formal instruction (I read The Silent World, by Jacques Cousteau, three times). I remember one early dive out of my parent's seven-man life raft in Elk Lake, using my Healthways Scuba double hose regulator and a 38 cubic foot tank. I was probably 15 years old at the time. I was alone, and lovin' it. The bottom was covered with aquatic weeds, and a few trout were circling around, but not expressing any interest in the bait my parents were offering.

I finned around for probably about 20 minutes, then started up when breathing became harder (I was using a restricted orifice reserve, built into my Healthways Scuba regulator). But before I surfaced, my Grandmother, who was in the boat and very nervous about my being underwater, finally became agitated and told my Dad, "Tell him to come up! TELL HIM TO COME UP!"

My Dad simply turned to her and asked, "How?"

It was not until 1963, when we had hired a California scuba instructor named Roy France, that we got certified, LA County. Until then, I was sometimes diving with a buddy, sometimes solo before solo was known as a specialty. So, how did I, as a kid, survive?

Well, let's look at it from the standpoint of Dr. Stanley Miles' Accident Equation (published in his book, Underwater Medicine).

A = CE(prf/tms), where A = accident; C = Chance; E = Environment; p = accident proness; r = risk acceptance; f = physical factors; divided by the factor of t = training; m = maturity; and s = safety measures.

I had been a water kid since age six, on age-group swim teams from about age ten through high school into college, had gone through lifeguard training, and had become by high school a WSI, or Water Safety Instructor. Plugging these into the equation above from Dr. Miles, you can see that I was very high in the denominator of that equation, and dove lakes and rivers that were shallow and pretty tame (although the rivers did have currents and cold). I was also using a very, very simple Healthways Scuba regulator (six moving parts--one reason the Cousteau teams used the Mistral, which was similarly a six-moving-part scuba). The chances of a scuba unit malfunction at depth were minuscule. That simply left watermanship (now a pretty sexist statement) as a factor, and I was more than at ease in the water.

So when I see a specialty course in "solo diving," I chuckle a bit. What this course is set up for is those who are not especially comfortable diving, who must be equipment-dependent for their safety. Someone above mentioned a emergency swimming ascent (CESR) as not practical for depths beyond about 25 feet. If you've read The Silent World, you will understand that Frédéric Dumas, when he taught the first scuba courses in France, had his divers do a CESR from 100 feet.

So today's students are very, very different from those at the beginning. Today's students are equipment-dependent because of their lack of water skills, and the types of instruction that they get. We don't require these divers to be proficient in the water, much less swim team members, to dive. That throws Dr. Miles' equation over toward needing things like redundent air. Today's regulators seem to be less reliable than those of yesteryear too. So we need redundant scuba to survive.

I am a safety professional (retired after over years in the occupational safety and health fields). Would I tell someone to solo dive without redundant air? No! Not in today's world. But I sometimes do that, even at age 73, I dive vintage gear sometimes in rather tame conditions (with lifeguards on the cliffs above). I also dive different configurations of gear. Two days ago, I dove solo with a twin 52 setup and my Mossback Mk 3 regulator (a modification of the DA Aquamaster that has a balanced first stage, with both LP and HP outlets), an octopus, dive computer, and LP inflator for my Para-Sea BC (my own invention--that's another story entirely).

What I've found is that the old gear that we used in the mid-1960s through 1990s was rather good gear, with fewer failure points, and easier access than today's gear. I read one poster above stating that he knew which regulator he was handling by feel, as each had a different LP fitting, and I wondered how that would work with thick neoprene diving gloves in cold water?

Here is one of my solo dives.

1) when you were starting out "you didn't know what you didn't know "

2) Did you ever find out what was causing the fish kill?

 

[John C. Ratliff]

1) when you were starting out "you didn't know what you didn't know "

2) Did you ever find out what was causing the fish kill?

Yes, the fish kill was caused by high river water temperatures. The water was over 70 degrees F, and at that temp the water cannot hold enough oxygen to keep salmon alive.

SeaRat

 

[John C. Ratliff]

Well, let's do a thought experiment, and say the controlled emergency ascent started at 66 feet rather than 70 feet of sea water. That's 2 atmospheres depth, but 3 atmospheres absolute pressure. The air at 66 feet is therefor 3 times denser than on the surface. AfterDark stated that he had a regulator malfunction whereby he had exhaled fully, and could not inhale after that exhalation. Therefore, his lungs held only their residual air, about 2 liters of air. That air, as it rises in the water column expands, and at the surface will be three times its original volume, or six liters. Most people have a vital capacity of only 4-5 liters of air, so lung overexpansion, and pulmonary barotrauma can de expected if no air is exhaled. But, at 33 feet, where the pressure is 2 atmospheres absolute, that same air is just reaching the lung's vital capacity, at 3 liters. It is reasonable to expect that no air would be expelled out the open airway until reaching approximately the lung's vital capacity, so expanding air starts coming out somewhere around the two atmosphere absolute pressure mark, or around 33 feet depth.

SeaRat

PS, tursiops, this wasn't meant for you, as I know you already understand it.

 

[tursiops]

Well, let's do a thought experiment, and say the controlled emergency ascent started at 66 feet rather than 70 feet of sea water. That's 2 atmospheres depth, but 3 atmospheres absolute pressure. The air at 66 feet is therefor 3 times denser than on the surface. AfterDark stated that he had a regulator malfunction whereby he had exhaled fully, and could not inhale after that exhalation. Therefore, his lungs held only their residual air, about 2 liters of air. That air, as it rises in the water column expands, and at the surface will be three times its original volume, or six liters. Most people have a vital capacity of only 4-5 liters of air, so lung overexpansion, and pulmonary barotrauma can de expected if no air is exhaled. But, at 33 feet, where the pressure is 2 atmospheres absolute, that same air is just reaching the lung's vital capacity, at 3 liters. It is reasonable to expect that no air would be expelled out the open airway until reaching approximately the lung's vital capacity, so expanding air starts coming out somewhere around the two atmosphere absolute pressure mark, or around 33 feet depth.

Nice job with the numbers.

 

[chillyinCanada]

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