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Thread: So what is this "SCR Mode" talk all about?

  1. #131
    RBW Member Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike's Avatar
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    Re: So what is this "SCR Mode" talk all about?

    if in doubt bail to OC


    but come on be honest, we are useless humans fighting our natural primevil instincts


    what this means is


    "if in doubt bail to OC"

    translates in the real world to


    "If in no doubt bail to OC"



    Any safety protocal MUST take into consideration human nature

    ergo we have to acknowledge the if in doubt protocal will serve to ensure divers will only bail when they are realy effected - perhaps to the point where they can no longer bail. we see this all the time



    the if in doubt protocol fails to deal with the reality that the 1st symptom of co2 is DENIAL!


    So what we teach is if in doubt bail (knowing full well humans wont bail until there is no doubt) but what we also teach is if in ANY doubt at all FLUSH, sanity check + monitor in the hope that will encourgage earlier diagnosis, because humans would far sooner flush than bail


    Im not saying we shouldnt teach "if in doubt bail"

    im just pointing out why we also teach dill flushing and sanity breaths. (in acknowledgement that divers will actually practice "if in no doubt bail"
    Last edited by Drmike; 25th April 2012 at 02:08.

  2. #132
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    Re: So what is this "SCR Mode" talk all about?

    Sorry to hijack this thread,
    But speaking of CO2, does anyone know where I can get an exhaled CO2 monitor? one of those handheld portable digital meters used in sports labs?

    There was a thread (couldn't find it again) with lab results far exceeding the CE CO2 output benchmarks, hence I wanted to check personal (comfort) levels.

    Thanks,

  3. #133
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    Re: So what is this "SCR Mode" talk all about?

    Quote Originally Posted by lizardland  View Original Post
    I'd probably do SCR as well. It's one thing having a calculated amount of gas, another finding out if it was right. Why spunk the gas when you don't need to? If someone gives you the ability to breathe at 15l/min or 4l/min then I know what I'd choose. As long as the loop is intact and the scrubber working I can't see a downside. If I was only a couple of minutes away then maybe I'd just go OC but if I was at the other end of the wreck then I'd SCR.
    Exactly.

    Most of my dives are scooter runs that take me an hour or more from my entry so I like to conserve my bottom gas if at all possible. I bring enough gas but why waste?

    If its just a down the shot and look at a wreck kind of dive then I might only go OC. Then again if I'm penetrating or any other sort of buisness then I'd go SCR.

    I don't want to have to think through a plethora of possibilities when on bottom. I like it clear cut and do the same thing every time. Do your planning/thinking on the surface and rely on simple procedure on bottom.

    Cam

  4. #134
    So many CCR So little etc Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase's Avatar
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    Re: So what is this "SCR Mode" talk all about?

    Quote Originally Posted by Drmike  View Original Post
    nonsense. suggest you think more and type less


    flushing does the exact same thing going to oc does, it lowers your inspired co2.

    ergo if after flushing you dont feel any different - then there was no co2 in the loop


    remember we are not talking about flushing to SOLVE co2 levels or reduce them to zero. if there truly is rising co2 in the loop we only need to lower levels of inspired co2 enough to see if we feel any different after doing so

    once verified that there is some co2 in the loop (rememeber we are at early stage not full on hit we are not talking high levels) we can decide on how to deal with it (oc bail or scr)


    Sadly I think a lot and that is possibly my problem. I also read a lot and i spend a lot of time talking to divers with actual C02 experience, and that totally screws me up.

    All I have read and all I have discussed with divers who have suffered C02 hits leads me to beleive that one or even several breaths on fresh gas is going to do nothing to provide any meaningful respite from a C02 hit.

    If you feel better that quickly it's either a placebo effect or its not C02

    All the divers I have discussed it with found the feelings related to C02 lasted a long long time. The only single thing that offered respite was getting significantly shallower and that is I believe as a direct result in the reduction of the narcotic effect and not in any reduction in inspired or retained C02 blood levels.


    Please feel free to continue with the put downs and persoanl insults, they make me smile, but I dont beleive they cover up the large hole in the logic of sanity breaths.

    ATB

    Mark

  5. #135
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    Re: So what is this "SCR Mode" talk all about?

    Quote Originally Posted by lizardland  View Original Post
    I'd probably do SCR as well. It's one thing having a calculated amount of gas, another finding out if it was right. Why spunk the gas when you don't need to? If someone gives you the ability to breathe at 15l/min or 4l/min then I know what I'd choose. As long as the loop is intact and the scrubber working I can't see a downside. If I was only a couple of minutes away then maybe I'd just go OC but if I was at the other end of the wreck then I'd SCR.

    Because my bailout plan is for 25 SAC and there is no way on earth id ever run 25 SAC unless I had a C02 issue or I was working hard unexpectedly.

    My normal diving SAC is arround 12lpm and on OC id plan for 15 for the working phase. Deco my SAC is usualy about 8 and i plan for 10. Having bailed out a couple of times i am happy to say my SAC was still sub 15.

    So if the bailout was benign id happily go OC all the way out as i am totaly confident on making it seeing as my gas plan is 25.


    Benign bailouts are flooded units, failed displays or lets say total loss of 02 thease are easy relaxed OC exits

    Non benign bailouts would include some stress or work load thats forced my SAC up or its a C02 hit.

    C02 and SCR? thats a dangerous place which id try and avoid. I'd blow a fair chunk of deco to avoid SCR as I beleive it would make things worse and the beleife alown would guarentee the result

    High workload? yes I can see the need for SCR but id be concerend about the combination of stress / WOB and C02 retention.


    The final area where SCR would be high up on the list would be small margin bailouts. This i beleive is the area where Dr Mike and perhaps your self are finding great comfort in SCR.

    I know divers who have done big dives and planned bailouts bassed on 15 SACs because the gas needed for 25 and 30SAC was massive. I wouldn't be averse to doing this my self if the need arose. If I was at the furthest point and needed to bail OC and i had calculated 15 SAC id defo use SCR to ensure my exit.

    Not reely the point of this thread though


    ATB

    Mark

  6. #136
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    Re: So what is this "SCR Mode" talk all about?

    Quote Originally Posted by Mark Chase  View Original Post
    All I have read and all I have discussed with divers who have suffered C02 hits leads me to beleive that one or even several breaths on fresh gas is going to do nothing to provide any meaningful respite from a C02 hit.

    If you feel better that quickly it's either a placebo effect or its not C02

    All the divers I have discussed it with found the feelings related to C02 lasted a long long time. The only single thing that offered respite was getting significantly shallower and that is I believe as a direct result in the reduction of the narcotic effect and not in any reduction in inspired or retained C02 blood levels.
    I also doubt that a few sanity breaths will help someone who is having a full-blown CO2 event recover in just a couple breaths, however, I think it could help someone who is starting to experience CO2 symptoms.

    I have very limited experience with CO2, however, I did run into some problems during a wreck penetration at 60m. Going into the wreck was a tight path going upwards on a 45 degree angle. It was fairly tight, but going in I felt very comfortable and agile. After turning around, we had to exit the wreck in a slightly head down position. I found the exit somewhat challenging. I was fumbling with the reel, I felt very awkward and just all-round uncomfortable. I decided to go OC for a couple seconds (just like they reinforced during the training), and wow, I instantly felt better. The slight head down position put the couterlungs above my lungs and greatly increased the hydrostatic pressure and I had built up a bunch of CO2. I didn't even realize it before taking my sanity breaths. It only took a few breaths and I was feeling much better and continued my exit on OC. For small amounts of CO2, sanity breaths can help prevent a full-blown CO2 event.

    FWIW, my training encouraged to take sanity breaths often. I was taught that if anything "feels" wrong, take sanity breaths. If there is any failure, go to OC to diagnose/fix the problem, and then either go back on the loop or stay OC depending on the situation.

  7. #137
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    Re: So what is this "SCR Mode" talk all about?

    Quote Originally Posted by Mark Chase  View Original Post
    All I have read and all I have discussed with divers who have suffered C02 hits leads me to beleive that one or even several breaths on fresh gas is going to do nothing to provide any meaningful respite from a C02 hit.

    If you feel better that quickly it's either a placebo effect or its not C02


    Mark
    Mark I can tell you from my OWN experience that several breaths of fresh gas make HUGE difference. Probably not when you are in full blown CO2 attack. The point is not never let it go that far - hence sanity breaths.

    Quote Originally Posted by Mark Chase  View Original Post
    So if the bailout was benign id happily go OC all the way out as i am totaly confident on making it seeing as my gas plan is 25.


    Benign bailouts are flooded units, failed displays or lets say total loss of 02 thease are easy relaxed OC exits


    ATB

    Mark
    If I am several miles in, deep in small silty cave I do not consider "flooded unit, failed display or loss of O2" benign. One way to make exit more relaxed would be to use SCR so I can reduce one of the stress factors - time limit on my OC gas. You can take wrong turn on the way out, get silted out, scooter might fail, miss your staged bailout (or someone can take it, move it), etc...
    Why not have as much gas as possible to get out?

    Quote Originally Posted by Steve Schultz  View Original Post
    I was fumbling with the reel, I felt very awkward and just all-round uncomfortable. I decided to go OC for a couple seconds (just like they reinforced during the training), and wow, I instantly felt better. The slight head down position put the couterlungs above my lungs and greatly increased the hydrostatic pressure and I had built up a bunch of CO2. I didn't even realize it before taking my sanity breaths. It only took a few breaths and I was feeling much better and continued my exit on OC. For small amounts of CO2, sanity breaths can help prevent a full-blown CO2 event.

    FWIW, my training encouraged to take sanity breaths often. I was taught that if anything "feels" wrong, take sanity breaths. If there is any failure, go to OC to diagnose/fix the problem, and then either go back on the loop or stay OC depending on the situation.
    Exactly!

  8. #138
    So many CCR So little etc Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase's Avatar
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    Re: So what is this "SCR Mode" talk all about?

    Quote Originally Posted by lof  View Original Post
    Mark I can tell you from my OWN experience that several breaths of fresh gas make HUGE difference. Probably not when you are in full blown CO2 attack. The point is not never let it go that far - hence sanity breaths.



    If I am several miles in, deep in small silty cave I do not consider "flooded unit, failed display or loss of O2" benign. One way to make exit more relaxed would be to use SCR so I can reduce one of the stress factors - time limit on my OC gas. You can take wrong turn on the way out, get silted out, scooter might fail, miss your staged bailout (or someone can take it, move it), etc...
    Why not have as much gas as possible to get out?



    Exactly!



    It kind of smaks in the face of what I have read about off gassing C02 but if you say it worked for you I cant argue with that.

    As for the bailout scinario.

    Prety extreem examples but how would you have done the dive on OC?

    Surely at some point you have to trust your dive planning?

    Having a further option to again increase the margin is an advantage in such extreem dives, but Id hope the focus of this discussion is its only for more extreem dives that very few are actualy getting involved in.

    Extreem diving in terms of conditions, depth or OHE comitment is a dive with significant increases in risk to the diver. SCR is an option also with significant increases in risk to the diver. It is a life saver but its not without risk in comparison with a conventional OC bailout option.


    Dispite all the slagging and extreem examples for justification, thats the only point i am trying to make.


    People who beleive there is clear emphasis put on the risks of SCR during Mod1 and Mod3 training are not meeting the divers who i meet who extole its virtues for the most basic dives and also as a primary bailout fix.


    ATB

    Mark

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