Scuba diving question

I used to scuba dive, once I ran out of air in about 40 feet of water. My reserve air had gotten pulled when I snagged it on something and I didn't notice it. So I'm in 40 feet of water, I exhale, go to inhale and get a very little bit, then nothing. It's like closing your mouth, pinching your nose then trying to inhale, nothing happens. My buddy was near by, I gave him the no air signal, he gave me a puff off his mouthpiece and we went up. The thing about ascending is the air expands in your lungs, so you are constantly exhaling as you go up, I think I needed one more puff before we got to the surface. Unfortunately the difference for this guy was he couldn't get to the surface.
 
CC268 said:
Wait so if it is so tight how are they getting the kids out?
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I believe the tightness means that the tanks have to come off before they make it through. From what I under stand, the kids won't be wearing the tanks at all. I'm guessing the kids are skinnier than the rescuers, so if they can fit, the kids can fit.
 
I've run tanks out a couple of times (once in the pool during a lesson, long story). I also had a regulator fail during a dive in Crystal River-exhaled, then when I inhaled I got a mouth full of water. I did a free assent from about 45' down in the cavern. When you run a tank dry, you get a breath or two where it's harder to suck the air, then nothing. If you're focused on something else, you might not notice until the "nothing" breath. As soon as you rise a little (typically a few feet), you can grab another shallow breath if you need one. As was said above, doing a free assent (don't rise faster than your bubbles!) is a weird feeling: you just exhale continuously as the pressurized air in your lungs expands. NEVER HOLD YOUR BREATH when ascending (or really when breathing pressurized air)!

I'm older and wiser now and I'd never dive with some of the equipment my dad and I used then. But just like flying, it's an accident chain and risk management. I've never done any cave diving, only caverns (You can see the surface from inside). If I did, I'd have to have a bunch of redundant gear and a very trusted dive buddy.

John
 
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CC268 said:
Wait so if it is so tight how are they getting the kids out?
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Really long regulator hoses? I don't know that I would want to be dragging a tank and a kid around in that kind of environment. Heck, I don't think I'd want to be dragging myself around in there without all the water. BTDT, but those days are past for me.
 
9 foot hoses are standard fair in a cave diving setup so it can reach your buddy if you have to swim in tandom through narrows.
 
Year's ago I was a hobby diver. Once made a tankless ascent from 100'. Boyle's Law and all, just don't breath. After WW2:

"Postwar, submariner Walter F. Schlech, Jr., among others, examined submerged escape without breathing devices and discovered ascent was possible from as deep as 300 ft (91 m): "in one sense, the Momsen Lung concept may have killed far more submariners than it rescued".
 
ejensen said:
Year's ago I was a hobby diver. Once made a tankless ascent from 100'. Boyle's Law and all, just don't breath. After WW2:

"Postwar, submariner Walter F. Schlech, Jr., among others, examined submerged escape without breathing devices and discovered ascent was possible from as deep as 300 ft (91 m): "in one sense, the Momsen Lung concept may have killed far more submariners than it rescued".
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Submariners are still taught a free ascent. You blow bubbles as you ascend, "ho-ho-ho" all the way to the surface. There used to be a 100' tall tower in Groton for this, but it basically rusted and was not replaced. Today there is a trainer, but it is only 10 or 15'

Considering that someone on a sunk boat was living in their future tomb, Momson lungs saved at least some people who would have otherwise died.

If memory serves me correctly, you could theoretically do this from as deep as 700', but you only had 20 seconds from pressurizing the escape hatch to beginning an ascent before nitrogen build up would cause problems at the surface - the bends.
 
bflynn said:
If memory serves me correctly, you could theoretically do this from as deep as 700', but you only had 20 seconds from pressurizing the escape hatch to beginning an ascent before nitrogen build up would cause problems at the surface - the bends.
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So, the boat is at one atmosphere. You pressurize the escape hatch to a LOT of atmospheres at 700', then you have 20 seconds before nitrogen begins building up to cause the bends from all that pressure (and its subsequent release)? In that situation, do you swim for the surface, or float? Seems like 700' would be a LONG ride up time wise, even if you're blowing bubbles the entire way (which implies your lungs are full). I mean, I was a good swimmer, but 700' > 200 yards, and a 200 yard swim at surface level is >2 minutes for anyone who's not an Olympian or close. Holding your breath for >2 minutes seems improbable for 99% of the population.
 
bflynn said:
Submariners are still taught a free ascent. You blow bubbles as you ascend, "ho-ho-ho" all the way to the surface.
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How I was tought was to just keep looking up. Air will naturally escape via your mouth and nose as the outside pressure goes down.

You then don’t risk getting rid of too much air too soon and building up too high a percentage of CO2 in your lungs in return that will cause you to gasp for more air.
 
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kyleb said:
So, the boat is at one atmosphere. You pressurize the escape hatch to a LOT of atmospheres at 700', then you have 20 seconds before nitrogen begins building up to cause the bends from all that pressure (and its subsequent release)? In that situation, do you swim for the surface, or float? Seems like 700' would be a LONG ride up time wise, even if you're blowing bubbles the entire way (which implies your lungs are full). I mean, I was a good swimmer, but 700' > 200 yards, and a 200 yard swim at surface level is >2 minutes for anyone who's not an Olympian or close. Holding your breath for >2 minutes seems improbable for 99% of the population.
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You don't hold your breath, if you did, your lungs would explode. You have to exhale all the way. But 500' is like 16 atmospheres. That's like 16 lungfuls of oxygen at the surface.
 
Lindberg said:
You don't hold your breath, if you did, your lungs would explode. You have to exhale all the way. But 500' is like 16 atmospheres. That's like 16 lungfuls of oxygen at the surface.
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I should have said "exhaling continuously without taking in a breath"...
 
It is completely unnatural, hence the reason for training. Submariners live in a world of basic physics every day...air pressure, water flow, psi, water pressure. This is just one more aspect of it.

On an ascent you now have a full exposure suit that forms an air bubble around you and provides buoyancy. Previously it was a Steike hood over your head. Before that, the momson lung, which is like a breathing bladder. It is getting better.

Not sure how any of this would apply to a cave rescue.
 
A great day, indeed. When I saw a drawing of where they were, and so far back, I wasn't optimistic. The rescue team pulled off a miracle, no doubt due to a lot of planning, skill and ambition. I hope they receive the accolades they deserve.

I read where the parents, a few days ago, banded together to send a message to the coach to say that they did not feel he was responsible. That says a lot about the kind of people they are. Outcomes like this just make you feel good about life.
 
Gerhardt said:
I read where the parents, a few days ago, banded together to send a message to the coach to say that they did not feel he was responsible. That says a lot about the kind of people they are. Outcomes like this just make you feel good about life.
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Although he's the one that inadvertently got them into the mess, I'm thinking the coach just might be the real hero. It couldn't be easy to keep 12 kids, teenagers even, in line enough for them to survive 10 days with very little food or hope. It'll be interesting to hear their stories.
 
I hope they make a movie about this.
I kinda figured they would about the Chilean miner incident but that died out quickly.
 
SixPapaCharlie said:
I hope they make a movie about this.
I kinda figured they would about the Chilean miner incident but that died out quickly.
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Certainly could be a better movie than most. I just saw the 13 hours: The Secret Soldiers of Benghazi and liked it.

(I must be getting too old to care about all the fantasy crap movies these days)
 
Gerhardt said:
A great day, indeed. When I saw a drawing of where they were, and so far back, I wasn't optimistic. The rescue team pulled off a miracle, no doubt due to a lot of planning, skill and ambition. I hope they receive the accolades they deserve.
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I'm not sure how many divers were involved - but wasn't it a 4 mile and almost 20+ hr round trip? And they made 3-4 trips?
 
Matthew said:
I'm not sure how many divers were involved - but wasn't it a 4 mile and almost 20+ hr round trip? And they made 3-4 trips?
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I had read 11 hours. I also read that they were getting better at it. They got the second four boys out 2 hours faster than the first four.
 
Dave Theisen said:
I had read 11 hours. I also read that they were getting better at it. They got the second four boys out 2 hours faster than the first four.
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I had seen 11 hrs, but I though that was one-way, maybe not. But it's over - I wonder how many divers are still back in the cave and having to work their way out now?
 
bflynn said:
Submariners are still taught a free ascent. You blow bubbles as you ascend, "ho-ho-ho" all the way to the surface. There used to be a 100' tall tower in Groton for this, but it basically rusted and was not replaced. Today there is a trainer, but it is only 10 or 15'

Considering that someone on a sunk boat was living in their future tomb, Momson lungs saved at least some people who would have otherwise died.

If memory serves me correctly, you could theoretically do this from as deep as 700', but you only had 20 seconds from pressurizing the escape hatch to beginning an ascent before nitrogen build up would cause problems at the surface - the bends.
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Or narcosis. And I agree, I'd have tried anything to get out of a disabled sub.
 
Ran across this graphic today. No idea if it’s accurate.

d52153079937683aa187250881fcd9d2.jpg
 
bnt83 said:
Certainly could be a better movie than most. I just saw the 13 hours: The Secret Soldiers of Benghazi and liked it.

(I must be getting too old to care about all the fantasy crap movies these days)
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I had the opportunity to meet one of the “private” security guys that was on the ground during that deal. A very impressive individual. I don’t think he liked HRC very much.
 
denverpilot said:
Ran across this graphic today. No idea if it’s accurate.

d52153079937683aa187250881fcd9d2.jpg
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Wow 3 hours of underwater swimming. I would be terrified swimming out of there. I guess it’s that or die though...
 
The cave where they were trapped filled with water soon after the last rescue forcing the teams to leave lots of equipment behind. Sounds like an opportunity to score some state of the art equipment when things drain back out.
 
Talk about a epic effort that totally paid off but at the cost of someone who must have been an awesome individual!!!

Some things people don't think about:
  • They really got lucky on the water temp, but 3hrs in the water and you're gonna get cold. Hard to imagine they were wearing drysuits - which would have been an even bigger feat.
  • EARS!!! The first thing that gets most people when learning to dive is clearing ears. And its the first 6-20ft or so that really bothers people. So everyone must have gotten past this or they had a medic/doc purposely pinhole their eardrums. I see they had a full face mask, but even a helmet will need to seek equal outside pressure regarding ears.
  • The exhalation force is really barely noticeable as long at the regulator is setup right.
  • A panic would probably be deadly as a panic'd diver will blow throw air so fast is crazy.
  • The comfort/pride of a pair of Thai Navy SEAL divers for each kid must have been so amazing for them.
  • I would think they would have been given a nitrox mix (maybe EAN 36 or EAN40) for such a long dive time, but then again it was shallow.
  • When you start working with the shear number of scuba tanks these guys are dealing with (perhaps 100's) you will have all sorts of leaks from the tank to yoke o-ring and yoke to regulator o-ring. They are often small leaks that you just dive with anyways. Perhaps the perished diver had a small leak in one of these rings leading to him running out 3%...5% faster than his teammates on an already tight margin.
Some Submarine things people don't really think about:
  • I was trained during the times of the Steinke Hood. It is no fun to put on as it fits incredibly tight. It has a clear plastic window so you could probably see out.
  • When you enter the LET (Logistic Escape Trunk) there is a heavy metal curtain/shroud hanging down from the outside hatch about a 2ft or so. You enter the trunk from the submarine side (bottom) and gather outside that shroud.
  • The chamber is then equalized to pressure and filled with water. But there is no water outside the shroud were you are gathered.
  • Once again EARS!!! I was told that someone would have a needle to puncture eardrums if needed.
  • A submarine escape option is merely to make moms feel safe. With the exception of transits, the operational bottom depth is so deep that the submarine will implode way before it would rest on the bottom and allow an escape. Heck even the DSRV' couldn't go that deep. And thus it was a perfect ruse to really be a cold war spy device.
  • The cold. A lot of submarine ops are not in tropical waters. Sure, escape but unless you have a drysuit you'll probably exit the escape chamber at 33F and maybe it will be 40F or 50F at the surface.
  • And if you do survive to the surface you might be in 30ft waves for days, good luck being found even with signaling equipment.
  • Regular compressed air even at 130ft starts to pose an 02 toxicity fairly quickly. And as others have mentioned all that extra nitrogen (due to the air being compressed will make you stupid since you are "narc'd").
...someone should sign off these boy's dive cards :)
 
Sinistar said:
...
  • The cold. A lot of submarine ops are not in tropical waters. Sure, escape but unless you have a drysuit you'll probably exit the escape chamber at 33F and maybe it will be 40F or 50F at the surface.
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My nephew, the one on the boat, once said, "I don't want to die underwater, it's COLD!"

--

Latest news reports are saying the kids were given a dose of anti-anxiety medication as a way to prevent panic.

Apparently the pump that was keeping the intermediate chambers empty failed after the last of the kids were out but while there were still divers at the far end of the cave. They had to scramble to get out before the other chambers with their reserve air tanks were flooded.
 
Matthew said:
Latest news reports are saying the kids were given a dose of anti-anxiety medication as a way to prevent panic.
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I heard that too... in fact, not just "a dose", but enough to cause HEAVY sedation. It was hinted that the kids were only semi-conscious and were basically being carried out. No idea if that's true, but that's what the report said (on NPR).
 
azure said:
I heard that too... in fact, not just "a dose", but enough to cause HEAVY sedation. It was hinted that the kids were only semi-conscious and were basically being carried out. No idea if that's true, but that's what the report said (on NPR).
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Their low body weight to start with, plus the weight they lost while trapped, plus whatever other physiological stress they were under might have made it tough to calculate the best dose. That might have also had something to do with why they were in such a hurry to get the kids to a hospital after pulling them out.
 
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