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Thread: Scuba diver dies after being found floating at Kurnell, NSW, Australia

 


  1. #621
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    Quote Originally Posted by Slamfire View Post
    Your head space plays a much greater roll in your breath hold endurance than having empty or full lungs at the beginning. Take this video where I am filming my 4 year old son as he swims in the pool. All of a sudden he starts heading towards me. I want him to be self reliant in the water, but I do not want to swim away and turn it into a chasing game. So I submerge. The best way to submerge and still keep him in camera is to simply exhale, since I am also on a snorkel with no fins and no wetsuit. I exhale in time stamp 0:32 and come up to breath at 0:55 or 0:56. That's 22 or 23 secs; very close to the max limits you stated for breatholding upon exhalation. I'm certain I could have easily lasted twice as much if I wanted to. When I came up you don't hear me desperately gasping for air, I took some cautious deep breaths initially to fill my lungs enough to blast remainders of water in the snorkel out. But that is it.
    You are missing the point and I am tired of flogging it. We will just have to agree to disagree on this one.

    ---------- Post added October 17th, 2013 at 04:47 PM ----------


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    Quote Originally Posted by S_Brown View Post
    Good luck with that....as a person who already admitted to being able to hold breath until you pass out, I guess that makes you the authority on uncontrollable physical reactions to air deprivation......sorry for stepping on your expert toes...
    Once again, all I am saying is that until you have actually and truly run out of air unexpectedly, at depth.....you don't know how you will really react. It's easy to armchair quarterback and theorize...... What was that phrase? "You don't know what you don't know"
    This is not about establishing myself as an expert or not. It's about a promoting healthy view regarding panic and controlling it. My dad used to teach me about diving and diving principles many years before he actually allowed me to go into the water with a tank. One of the things he drilled time and time again into my head is that if you give in to panic you will die much faster. Panic is not a clear cut line in the sand. It's a continuum of many different shades that goes from full black to pristine white. You say you did not panic in your incidents and I believe you. But do you think you could have brought your heart rate a little lower during those incidents? My dad used to say to me, "Go slow, because we're in a hurry". A UTD instructor around here says "if you think you're going slow, go slower". I think I heard somebody else say "slow is smooth, and smooth is fast."

    I have been in an OOA incident early on my diving. I brought the J valve down and nothing happened. I gave OOA signal to my dad as I start ascending slower than my small bubbles and my dad starts to rush at me trying to take my harness off. I pushed him off because I had no intention of abandoning a rig and potentially losing it. He did not fight me but stayed really close. We got to the surface and surface swam with an empty on my back.

    Ironically one of the last discussions I had with Quero was about the lack guidance related to panic management that you find in current OW courses. I believe it is absolutely essential material that is missing from the curriculum.
    Slamfire: The unintended firing of a piece of weaponry as a round is being loaded in the chamber.

  3. #623
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    Quote Originally Posted by Slamfire View Post
    20 or 30 secs to what? Did you go 31 secs and on that 31st second something horrible happened? Some of the MDs here can correct me if I'm wrong, but isn't it considered that normal humans can go about 5 mins without breathing before brain damage starts to happen?
    I am not an MD, but I have talked with one about this very topic. Yes, you go a long time before brain damage sets in, but you are unconscious for a while before that happens. It takes more than 30 seconds, though. I was told we usually have about 1 to 1.5 minutes of consciousness from the oxygen circulating in our blood if we do not inhale. Of course, if we inhale, we get a lot more.

    Quote Originally Posted by S_Brown View Post
    The hard breathing regulator is an indication....if you recognize it as such....as you do when you are expecting to run out of air. The deeper you are the less breaths you get as warning.
    My experience is the opposite. When I was assisting classes as a DM and had to do the air depletion exercise in the pool, I assure you that at that depth, there was no warning before OOA whatsoever. You are breathing just fine and then BANG!--nothing! When I have breathed stage bottles down to empty in deeper water, I have gotten some warning. When I have breathed them down at even greater depths--say 150 feet--I have gotten several breaths of warning.
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    Quote Originally Posted by NetDoc View Post
    This diver’s identity has been confirmed by her dive buddies and I was promptly notified. We don't know all the details just yet, but the dive community lost one our brightest stars. Via con Dios, Marcia Fisk Ong, aka Quero, one of my Advisors.
    Many of us who knew and
    respected her will abstain from discussion in this thread. Suffice it to say that the Marcia’s last moments were spent doing what she loved - scuba diving.

    Please visit this thread in Passing to express your condolences.
    !!!WOW!!!

    I am only just now getting around to this. At first I wasn't quite sure who this was referring to; I am STUNNED!!! She was always a great voice of experience on the board, and I had much respect for her insight and wisdom. Incredible loss; deeply saddened by this news!!!

    My condolences to her family and loved ones.
    Last edited by Carlos Danger; October 18th, 2013 at 01:30 PM.

  5. #625
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    A couple of clarifications first. In Sydney we have common (or weedy) sea dragons, not leafy sea dragons. A totally different species that look quite different. In Sydney they are found normally deeper than 10 or 12 metres. I do not think I have ever seen one shallower in over 2,200 dives here. When they descended towards the end of the dive the water depth was 2.5 metres (maybe 3 at the most). Therefore it is unlikely Marcia saw a sea dragon, but she could have seen a sea horse as they do live on the weed in that area.

    Re lift rates for BCDs. The lift is calculated (according to Michael Hollis's evidence at the Gabe Watson murder trial which I attended), by filling the BCD (with no-one using it) till it is full and then placing weights on it till it sinks. This means the BCD is opened right out. As such, in a real life situation, it is unlikely that a BCD with 18 lbs of lift will actually lift 18 lbs when a diver is wearing it. It will be less. I expect that a normal BCD will lose a couple of pounds at least, a wing probably less.

    I have access to the dive profiles from 2 of the computers used on that dive. I have tried to work out an air consumption for Marcia's dive based on the profile of one of the computers. The following is what I found, using a two minute interval for my calculations (the profile depth is relatively flat for most of the dive).

    She had a 10 litre steel tank. If this was filled to 220 bar (a proper fill), then it had 2,200 litres of air. If it was filled only to 200 bar, then there was 2,000 litres of air. I do not know what it was filled to, but I will try to ascertain this.

    By my calculations, if Marcia had 220 bar, she averaged about 12.8 litres RMV (SAC) on the dive. If she had 200 bar, then she averaged 11.8 bar. Both of these are very low consumption rates for a diver in Sydney, especially when using a drysuit. I have one of the lowest RMV's of the people I dive with in Sydney. Using my drysuit it is about 12 to 12.5 or so, depending on the dive. I would expect a diver, no matter how experienced, diving in Sydney for the first time and using a drysuit for only the fourth time to use at least that much. Therefore, it is easy to see that she was likely to run out of air.

    Going to the time when she surfaced, I believe that she probably only had between 15 and 20 bar in her tank. However, this would have read as 25 to 30 bar considering the gauge appears to have read 10 bar when empty. Therefore, I believe that the reported figure of 50 bar that she told her buddies was probably a guess on her behalf, perhaps taken a few minutes before they ascended. I think that when she went back down she realised that she indeed had far less, perhaps the 25 to 30 bar I calculated. She then decided that she needed to swim a bit quicker to get to shore before it ran out.

    Thus, she left her three buddies and swam off, thinking she was going to get to shore before it ran out (she may have even known that her gauge was not accurate). This would have used more air per minute than she had previously been using. Then she ran out and did not have enough to inflate her drysuit to achieve at least neutral buoyancy.
    Last edited by clownfishsydney; October 17th, 2013 at 09:41 PM. Reason: Corrected error - 15 to 25
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  6. #626
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    Quote Originally Posted by Slamfire View Post
    Your ability to solve problems while breath holding is not contingent on whether you have your lungs full or not. You just exhaled and your blood is still fully oxygenated. It might feel worse, but you can still operate for quite a while. Exactly. And knee jerk, panicked reactions are some of the best ways to waste time. When you want endurance, you don't go out full throttle. Reduce your heartbeat, establish a rhythm and a cadence of purposeful and efficient movements/actions.

    20 or 30 secs to what? Did you go 31 secs and on that 31st second something horrible happened? Some of the MDs here can correct me if I'm wrong, but isn't it considered that normal humans can go about 5 mins without breathing before brain damage starts to happen? Try it in a pool or in the bathtub. Measure yourself. Breathing normally and without previous hyperventilation put your face in the water just after exhalation. See if you can go past 30 secs. Ahhh, you say, but this is not an emergency, there is no fear and no panic. EXACTLY my point, if you get yourself into the right headspace you will be a much more efficient operator under dire circumstances.
    Playing in a bathtub is analogous to a life or death emergency under the water? Ridiculous.. If you want to see how well you can function with no air in your lungs, exhale completely and try running up the steps.. I start feeling really crappy after just one floor and I know I can take a breath at any moment.
    je76 and S_Brown like this.
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    Quote Originally Posted by boulderjohn View Post
    I am not an MD, but I have talked with one about this very topic. Yes, you go a long time before brain damage sets in, but you are unconscious for a while before that happens. It takes more than 30 seconds, though. I was told we usually have about 1 to 1.5 minutes of consciousness from the oxygen circulating in our blood if we do not inhale. Of course, if we inhale, we get a lot more.
    I asked a similar question about how long it typically takes to loose consciousness from hypoxia. I imagine that it's quite variable? Based on personal physiology as well as current physical state. For example, I'd guess you wouldn't last quite so long if you were exerting yourself before and while holding your breath.


    And I asked the question because I was also wondering about a 'panic-less' hypothesis. I think a lot of discussions here quite rightly focus on managing stress and avoiding panic, since we know that it causes or exacerbates many incidents and accidents. But I was wondering if considering alternative possible explanations where it was not a factor might be helpful. Basically because, well, I wouldn't like to blindsided by some other issue while thinking 'I'm good, I'm not panicking, I have everything under control.'

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    Quote Originally Posted by clownfishsydney View Post
    A couple of clarifications first. In Sydney we have common (or weedy) sea dragons, not leafy sea dragons. A totally different species that look quite different. In Sydney they are found normally deeper than 10 or 12 metres. I do not think I have ever seen one shallower in over 2,200 dives here. When they descended towards the end of the dive the water depth was 2.5 metres (maybe 3 at the most). Therefore it is unlikely Marcia saw a sea dragon, but she could have seen a sea horse as they do live on the weed in that area.

    Re lift rates for BCDs. The lift is calculated (according to Michael Hollis's evidence at the Gabe Watson murder trial which I attended), by filling the BCD (with no-one using it) till it is full and then placing weights on it till it sinks. This means the BCD is opened right out. As such, in a real life situation, it is unlikely that a BCD with 18 lbs of lift will actually lift 18 lbs when a diver is wearing it. It will be less. I expect that a normal BCD will loss a couple of pounds at least, a wing probably less.

    I have access to the dive profiles from 2 of the computers used on that dive. I have tried to work out an air consumption for Marcia's dive based on the profile of one of the computers. The following is what I found, using a two minute interval for my calculations (the profile depth is relatively flat for most of the dive).

    She had a 10 litre steel tank. If this was filled to 220 bar (a proper fill), then it had 2,200 litres of air. If it was filled only to 200 bar, then there was 2,000 litres of air. I do not know what it was filled to, but I will try to ascertain this.

    By my calculations, if Marcia had 220 bar, she averaged about 12.8 litres RMV (SAC) on the dive. If she had 200 bar, then she averaged 11.8 bar. Both of these are very low consumption rates for a diver in Sydney, especially when using a drysuit. I have one of the lowest RMV's of the people I dive with in Sydney. Using my drysuit it is about 12 to 12.5 or so, depending on the dive. I would expect a diver, no matter how experienced, diving in Sydney for the first time and using a drysuit for only the fourth time to use at least that much. Therefore, it is easy to see that she was likely to run out of air.

    Going to the time when she surfaced, I believe that she probably only had between 15 and 20 bar in her tank. However, this would have read as 15 to 30 bar considering the gauge appears to have read 10 bar when empty. Therefore, I believe that the reported figure of 50 bar that she told her buddies was probably a guess on her behalf, perhaps taken a few minutes before they ascended. I think that when she went back down she realised that she indeed had far less, perhaps the 25 to 30 bar I calculated. She then decided that she needed to swim a bit quicker to get to shore before it ran out.

    Thus, she left her three buddies and swam off, thinking she was going to get to shore before it ran out (she may have even known that her gauge was not accurate). This would have used more air per minute than she had previously been using. Then she ran out and did not have enough to inflate her drysuit to achieve at least neutral buoyancy.
    The two big questions seem to be was she actually negative with the BC full and needed lift from the drysuit to be positive. If that is true then I can understand how she ran out of air but had problems reaching the surface easily. But if that is true the second big question is still why she was not able to ditch her weight or her whole rig.

    The first question could be answered by testing the exact equipment. The second question is likely to always remain a mystery.

  9. #629
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    Quote Originally Posted by dumpsterDiver View Post
    Playing in a bathtub is analogous to a life or death emergency under the water? Ridiculous.. If you want to see how well you can function with no air in your lungs, exhale completely and try running up the steps.. I start feeling really crappy after just one floor and I know I can take a breath at any moment.
    Of course it is not analogous. It was claimed that you could only last 30 secs on an exhalation breath hold. I challenged the claim and tried to illustrate that the calmer and less panicked you are, the longer you will last. If you can last 90 secs in a totally un-panicked bath tub situation maybe you could strive to improve your emergency breath-hold from 30 secs to a full minute. Up until now nobody was bringing up intense physical exertion (eg running up stairs). Obviously, you will burn more O2 if you are physically exerting. I don't think anybody will dispute that.

    DD, how many OW divers include "bring down my heart rate", as an item in their emergency procedures?
    Slamfire: The unintended firing of a piece of weaponry as a round is being loaded in the chamber.

  10. #630
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    Headed to the pool now for snorkeling and skin diving class. May do some experimenting. Kids need to train on bringing me up from the bottom anyway.
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