Lowest SAC possible ? (without being dead)
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Mike Veitch:
Mike, the first time I ever knew anything about SAC rates was when I started uploading my computer to my pc and it gave me that info for each dive. It's typically not important to me unless I'm planning a serious dive like deep or wreck penetration.
I do however introduce all my Advanced O/W students to the calculations. It's basically just putting a number on information that an experienced diver already knows and compensates for. You've probably done the calculation many times without the math when you say "I want to dive to "x" depth for "y" minutes and have "r" amount of air in reserve. Based on what I usually use for this type of dive I need a(n) 63, 80, 130cuft,. . ." Just a little redundancy, if you will.
mech
Contributor
Hi Fred,
Mind if I ask you a few questions?
How much N2 do you retain?
Have you been tested?
How does that alter your profile?
Thanks.
Andy
Mind if I ask you a few questions?
How much N2 do you retain?
Have you been tested?
How does that alter your profile?
Thanks.
Andy
Fred R.
Contributor
Remember, all this started because someone rudely said that diving with ankle weights marked a diver who didn't know what they were doing. And then the conversation degenerated with many claims of ankle weights causing fatigue and increased air consumption.
Pondfrog, among others, has dived with me. I do not think he would describe my diving as 'passing for dead'. I lead dives, every day (give or take a few bad weather days) Leading means, among other things, I stay ahead of divers. This is also not 'passing for dead'.
Catherine, (love to read your posts, BTW) I've done almost entire dives finning backwards around the reef while I keep an eye on newbies who need it. I learned the finning backwards a full fifteen years before the formation of GUE, I had to come up with it myself because there was no one to teach it too me. Finning backwards, forwards, spins (whatever the 'cool' divers are calling it now) does not raise my breathing rate.
Diver0001, slow breathing is a sustainable activity. You are breathing slowly when you can keep it up indefinitely. Skip breathing is when you try to breath slower than your biological oxygen demand or slower than you can off-gas carbon dioxide (which is more likely, especially at depth) When you skip breath, you 'embarrass' your respiratory system and you have to increase your breathing speed to catch up. Since this is an exothermic process you can only lose.
In all my classes and coaching, I tell everyone who will listen, you need to breathe as much as you need to breathe. With beginners I say, Breathe however you need to.
Walk up a flight of stairs, when you reach the top, sit down. You've just embarrassed your respiratory system, you have to huff and puff for a few seconds or minutes, depending on how out of shape you are. Now walk up six flights of stairs. Your breathing catches up and you hit a rhythm that you can sustain. You are breathing like the average beginning diver, who does not know what muscles to use, and so attempts to use them all.
Meditation exercise; lay on your back on the floor. Relax every muscle until it feels like they are sinking into the floor. Spend fifteen minutes doing it. (if you fall asleep, start over when you wake up) Notice your breathing rate, it should not be anything like the stair stepping.
Back to scuba. You should be kitted out and ballasted so that if you do the relaxation exercise you are in your favorite swimming position without moving. You should be able to fall asleep like that in mid water and wake up in the same position (yes, I've done that a time or two in my 'single' years) Now try swimming around. I do not see very many people who can do it, but the safety stop is a good place to practice.
I show relatively new divers (25 dives or so) that trick, and teach them to scull with their fins, and most of them halve their air consumption rates in two or three dives.
To Freediver; that's what credit cards are for!
Pondfrog, among others, has dived with me. I do not think he would describe my diving as 'passing for dead'. I lead dives, every day (give or take a few bad weather days) Leading means, among other things, I stay ahead of divers. This is also not 'passing for dead'.
Catherine, (love to read your posts, BTW) I've done almost entire dives finning backwards around the reef while I keep an eye on newbies who need it. I learned the finning backwards a full fifteen years before the formation of GUE, I had to come up with it myself because there was no one to teach it too me. Finning backwards, forwards, spins (whatever the 'cool' divers are calling it now) does not raise my breathing rate.
Diver0001, slow breathing is a sustainable activity. You are breathing slowly when you can keep it up indefinitely. Skip breathing is when you try to breath slower than your biological oxygen demand or slower than you can off-gas carbon dioxide (which is more likely, especially at depth) When you skip breath, you 'embarrass' your respiratory system and you have to increase your breathing speed to catch up. Since this is an exothermic process you can only lose.
In all my classes and coaching, I tell everyone who will listen, you need to breathe as much as you need to breathe. With beginners I say, Breathe however you need to.
Walk up a flight of stairs, when you reach the top, sit down. You've just embarrassed your respiratory system, you have to huff and puff for a few seconds or minutes, depending on how out of shape you are. Now walk up six flights of stairs. Your breathing catches up and you hit a rhythm that you can sustain. You are breathing like the average beginning diver, who does not know what muscles to use, and so attempts to use them all.
Meditation exercise; lay on your back on the floor. Relax every muscle until it feels like they are sinking into the floor. Spend fifteen minutes doing it. (if you fall asleep, start over when you wake up) Notice your breathing rate, it should not be anything like the stair stepping.
Back to scuba. You should be kitted out and ballasted so that if you do the relaxation exercise you are in your favorite swimming position without moving. You should be able to fall asleep like that in mid water and wake up in the same position (yes, I've done that a time or two in my 'single' years) Now try swimming around. I do not see very many people who can do it, but the safety stop is a good place to practice.
I show relatively new divers (25 dives or so) that trick, and teach them to scull with their fins, and most of them halve their air consumption rates in two or three dives.
To Freediver; that's what credit cards are for!
Fred R.
Contributor
mech:
I assume the dive tables and dive computers work the same on me as everyone else. I have never been tested as there never seemed to be any point. I've also never been bent.
Discussing my profiles would hijack this thread in at least two other directions.
Short version;
According to all my research, it really doesn't matter so much how deep you go, or how long you stay (within reasonable recreational limits), what is really critical in who has problems is how you come up. While everyone on this board is perfect, the industry at large does not understand or teach this properly. If I were to say more, I might be accused of 'bashing'.
mech
Contributor
I felt that my questions were staying on topic....more or less due to possible safety issues.
The reasons that I asked was in one of my tech classes the instructor talked about N2testing/loading and how it applied in the real world.
One thing that he mentioned was that the local tech boat skipper is a freaking freak when it comes to SAC.
After a dive (while on the boat) they did testing.
Skipper was way spiked with N2 and the concenses was he needed to breath more because he was loading up.
Would not a freakishly low SAC spike the N2 a person is retaining?
My thoughts are if this is true it would/should alter a profile and the person should compensate by adding time to the SI or modifing the next dive plan.
Thanks again.
Andy
The reasons that I asked was in one of my tech classes the instructor talked about N2testing/loading and how it applied in the real world.
One thing that he mentioned was that the local tech boat skipper is a freaking freak when it comes to SAC.
After a dive (while on the boat) they did testing.
Skipper was way spiked with N2 and the concenses was he needed to breath more because he was loading up.
Would not a freakishly low SAC spike the N2 a person is retaining?
My thoughts are if this is true it would/should alter a profile and the person should compensate by adding time to the SI or modifing the next dive plan.
Thanks again.
Andy
Fred R.
Contributor
Hi Andy,
It has been my contention for many years that people come up too fast. Or to phrase it another way, do too few and too short safety stops.
I can not speak for the tech crowd, by definition they go to extremes for their own resons.
On ascent, N2 boils out of the lungs. It does so at a fixed rate according to the difference in pressure. Whether you breathe fast or slow, nitrogen should pass the lung membranes at the same rate.
Problems come into play when divers ride the edge, coming up as fast as the table maximum, hanging on stops for the minimum and generally not giving the body time to equalize to the pressure differential.
By coming up slowly, even with a very slow breathing rate, you give the body plenty of opportunity to equalize without bubble formation.
It has been my contention for many years that people come up too fast. Or to phrase it another way, do too few and too short safety stops.
I can not speak for the tech crowd, by definition they go to extremes for their own resons.
On ascent, N2 boils out of the lungs. It does so at a fixed rate according to the difference in pressure. Whether you breathe fast or slow, nitrogen should pass the lung membranes at the same rate.
Problems come into play when divers ride the edge, coming up as fast as the table maximum, hanging on stops for the minimum and generally not giving the body time to equalize to the pressure differential.
By coming up slowly, even with a very slow breathing rate, you give the body plenty of opportunity to equalize without bubble formation.
divinginn
Contributor
when is the book due out fred? sign me up for one.
ScubaMike14
Contributor
Hey all...man am I amazed at what this thread has turned into.
For starters, I did my AOW Class with Fred in 1999. I have done qute a few dives with him over the years and I must say he does "walk the walk". When underwater, he appears more like a porcupine fish than a human being. Those of you that have seem a porcupine fish, either in the ocean or perhaps in an aquarium know how they swim. They just seem to hover and go up, down, forward and back at will....without moving any of thier fins.
As for breathing..many times Fred will just grab an AL 50 or 63 and dive all day. That's 2 or 3 dives ALL DAY. And when he get's back to the dock and I go to fill the tank, I am amazed that there is a decent amount of air still in the tank.
Fred is the Zen Master - Mr. Miyagui (Karate Kid) when it comes to diving and air consumption. I can vouch for him 100%.
In my years of diving with him, I HAVE seen him suck a tank dry in about 10 minutes...ONCE.......but that dive involved a Blue Hole and a silly Divemaster Candidate......(remember Fred?)
Anyway, as for SAC rates I have come up with another measurement quite similar called a SACK rate. It only applies to men and it goes like this:
Water Temperature divided by thickness of Westuit in MM = SACK Rate. The number your wind up with is the speed at which your testicles will shrink. The higher the number the faster they turn to raisins.
Enough of my silly banter. See you on Saturday Fred!!
Mike Rushton
PADI DM 174448
For starters, I did my AOW Class with Fred in 1999. I have done qute a few dives with him over the years and I must say he does "walk the walk". When underwater, he appears more like a porcupine fish than a human being. Those of you that have seem a porcupine fish, either in the ocean or perhaps in an aquarium know how they swim. They just seem to hover and go up, down, forward and back at will....without moving any of thier fins.
As for breathing..many times Fred will just grab an AL 50 or 63 and dive all day. That's 2 or 3 dives ALL DAY. And when he get's back to the dock and I go to fill the tank, I am amazed that there is a decent amount of air still in the tank.
Fred is the Zen Master - Mr. Miyagui (Karate Kid) when it comes to diving and air consumption. I can vouch for him 100%.
In my years of diving with him, I HAVE seen him suck a tank dry in about 10 minutes...ONCE.......but that dive involved a Blue Hole and a silly Divemaster Candidate......(remember Fred?)
Anyway, as for SAC rates I have come up with another measurement quite similar called a SACK rate. It only applies to men and it goes like this:
Water Temperature divided by thickness of Westuit in MM = SACK Rate. The number your wind up with is the speed at which your testicles will shrink. The higher the number the faster they turn to raisins.
Enough of my silly banter. See you on Saturday Fred!!
Mike Rushton
PADI DM 174448
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