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Thread: Deep Stops

  1. #21
    Established TDF Member Iain Smith's Avatar
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    Welcome, Penny,

    That's one hell of a first post, though you might not have realised it!

    The topic can get extremely vocal (indeed, abusive, as already demonstrated by one poster) and has been debated in considerable detail and vitriol in a number of places (probably at greatest length here but certainly in places on this forum also) Not your fault, assuming you didn't know this!

    When reading opinions on this topic (as with any other aspect of biological sciences or healthcare), you would be well advised to look up the poster's qualifications and experience in science, physiology, medicine (specifically diving and hyperbaric medicine) and research (or lack thereof) in order to assess the credibility of the statements made. May also be worth looking at the backgrounds of those attacked and any commercial conflicts-of-interest relevant to those doing the attacking.

    Iain

  2. #22
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    Ross would you be happy to take the debate about Neal Pollockís presentation and the surrounding points to a seperate discussion? The context here is an innocent query from a new forum member. I figured that a relatively mainstream open source reference would be appropriate. Iím more than prepared to have the debate and learn but hijacking Pennyís thread with an advanced and esoteric debate doesnt seem right.

  3. #23
    "Three Sheds" Janos's Avatar
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    Quote Originally Posted by Tewdric View Post
    Ross would you be happy to take the debate about Neal Pollockís presentation and the surrounding points to a seperate discussion? The context here is an innocent query from a new forum member. I figured that a relatively mainstream open source reference would be appropriate. Iím more than prepared to have the debate and learn but hijacking Pennyís thread with an advanced and esoteric debate doesnt seem right.
    This was debated extensively at the time.
    The Rebreatherworld thread where Ross, Simon, and David debated the results is
    here

    Itís a long thread but worth reading. Thereís a lot of crap,in there but some good science half way through

    Personally, I no longer do deep stops, and run gf of 45/75.

    Janos
    You can lead a horse to water but you can't climb a ladder with a large bell in both hands - Vic Reeves
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    My music video: Dive the UK, cos that's the way it is. Huh!

  4. #24
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    Quote Originally Posted by Neilwood View Post
    If that is your take on it, fine. Dive whatever way you want to.

    Personally I will listen to the experts in the field of dive medicine like ...... Dr Simon Mitchell - they have spent a lot longer than most people investigating decompression stress and treating DCS. .....

    Your comment highlights the basic problem that is at the root of this argument. Many in the audience do not have the desire or ability to research these matters on their own. They cannot make an independent conclusion for themselves. So, just as you state, the reader will take it all at face value and follow the most qualified voice.

    But what happens when that voice is operating outside the peer review system and promoting a personal desire for change directly onto the public, based on scientifically invalid arguments? To the casual reader, it looks official. This leads directly to the situation we have now, which is a fait accompli.




    Quote Originally Posted by PhilPage View Post
    ......

    So rossh, you have issues with the structure of the experiment (and you're far more qualified to comment on that than me), do you disagree with the final conclusion?

    "The practical conclusion of this study is that controlling bubble formation in fast
    compartments with deep stops is unwarranted for air decompression dives."
    I find the conclusion to be frustratingly narrow and vague. Why would three of the most intelligent men in the field, abbreviate the conclusion to such a generic one liner?

    The test procedure did not evaluate deeper stops (as we know/use them), the profiles were artificially too long for any faster compartment to remain meaningful, so the conclusion is somewhat irrelevant to the paper.

    In the general sense the conclusion is both true and false. It's a true statement, because almost any type of realistic ascent will work successfully, meaning all others forms of ascent can be said to be non-essential / not warranted.

    It's also a false statement because the practical experience of millions of divers shows the opposite: the most common type of air / nitrox ascent is in divers in recreational field where the decade long trend has been towards slower ascents and various forms of short mid level stops. This type of diver / profile mostly encounters fast compartment based injuries, making them a good representation of fast compartment adjustments. This group has shown a continued reduction in treatment / injury rates over the last 15+ years. So clearly the deeper / slower / lower stress types of ascent do improve the outcome.

    Cheers.
    x

  5. #25
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    Quote Originally Posted by Tewdric View Post
    Ross would you be happy to take the debate about Neal Pollock’s presentation and the surrounding points to a seperate discussion? The context here is an innocent query from a new forum member. I figured that a relatively mainstream open source reference would be appropriate. I’m more than prepared to have the debate and learn but hijacking Penny’s thread with an advanced and esoteric debate doesnt seem right.
    Hi,

    I like what Neal Pollock writes and presents. He keeps it all in context and maintains a proper balance of the conflicting pieces. As long as you understood what Neal really said and means, then there is no debate.

    Cheers.
    x

  6. #26
    Old but keen Mark Chase's Avatar
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    Quote Originally Posted by Dave1w View Post
    I was alway a little puzzled that the studies were of just deep stops against just shallow stops and (when I looked at the ages ago) not deep stops with extra shallow stops as well.


    Sent from my iPhone using Tapatalk
    The study was on the profile not the deco time

    So two profiles were used which both represented the same in water time one with more deep stops and shorter shallow stops and the other with fewer deep stops and mainly shallow stops.

    The profile which spread the total decompression time over some of the deeper stops turned out to be the less effective / efficient /safe (pic your own word) profile.


    I know many many divers who went for deep stops and bubble modles when they first came into vogue

    They wernt doing the same deco as my Bhulman moddle they were doing significantly less and claiming the deep stops allowed them to do this.

    The infamas GI III once said "if you get the deep stops right the shallow stops don't matter" fortunately hes quit diveing and gone off bass fishing or he'd be under a world class pile of poo right now.

    I could never figure this out on the basses that more time deep = more on gassing?

    But now the emporors cloths have no been demonstrably proven as non existant.

    Deep stops are good for controlling the overall ascent and sorting kit out running checks and stuff like that.

    If you want to do deep stops that's fine but you need to extend the shallow stops to compensate for the time spent deep.

    Thers a 100 ways to do deco, and they all work if you spend enough time in the water in the shallow stops, but the question as to which one is the most efficient? Cleanest?

    I think that's been answered for now and its Bhulman with a step back for fitness levels.

    Despite this people are still hanging on desperately to deep stop diving despite claiming they "don't do deep stops"

    profiles like 45/75GF are a deep stop profile

    a no deep stop profile is 75/75GF

    I progressed away from deep stops over a year or two and now run 80/80 which works fine but then I started out running 20/90 and that worked fine too

    I am running 80/80 as the best available information today is this is the safest profile in comparison to say 10/125.

    I have had many a discussion with Ross over this and he puts forward some good points and some issues which border on foil hat stuff IMHO but my final word is always. Put up what ever profile you think is better and get it properly indipendantly tested.

    Then and only then will I listen

    I like 1000s listened to GUE and bubble moddel theory and in truth there was no testing to back it up except empirical testing. For many like me, the GUE stance of being hard core deep long deco divers and saying deep stops are the best, had massive influence. And they were doing 30% less deco than me and being safer???? or at least claiming to be more efficient. To this day the words of a GUE instructor rattle about in my head after I posted a dive profile. "Mark why are you doing so much deco?"

    SO having learnt my lesson I think Ill now stick to independent peer reviewed manned test data
    Last edited by Mark Chase; 24-11-2017 at 07:46 AM.

  7. #27
    Nicotine, valium, vicodin... notdeadyet's Avatar
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    Quote Originally Posted by Janos View Post
    This was debated extensively at the time.
    The Rebreatherworld thread where Ross, Simon, and David debated the results is
    here

    Itís a long thread but worth reading. Thereís a lot of crap,in there but some good science half way through

    Personally, I no longer do deep stops, and run gf of 45/75.

    Janos
    It is worth reading but the tl;dr version boils down to someone selling deco software arguing with someone involved in diving medicine about whose view of the world is right and it is down to the reader to decide who makes the most compelling argument.

    I've never like deep stop models, always felt less than great.

  8. #28
    GUE Instructor Badger's Avatar
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    Quote Originally Posted by Mark Chase View Post
    The study was on the profile not the deco time

    So two profiles were used which both represented the same in water time one with more deep stops and shorter shallow stops and the other with fewer deep stops and mainly shallow stops.

    The profile which spread the total decompression time over some of the deeper stops turned out to be the less effective / efficient /safe (pic your own word) profile.


    I know many many divers who went for deep stops and bubble modles when they first came into vogue

    They wernt doing the same deco as my Bhulman moddle they were doing significantly less and claiming the deep stops allowed them to do this.

    The infamas GI III once said "if you get the deep stops right the shallow stops don't matter" fortunately hes quit diveing and gone off bass fishing or he'd be under a world class pile of poo right now.

    I could never figure this out on the basses that more time deep = more on gassing?

    But now the emporors cloths have no been demonstrably proven as non existant.

    Deep stops are good for controlling the overall ascent and sorting kit out running checks and stuff like that.

    If you want to do deep stops that's fine but you need to extend the shallow stops to compensate for the time spent deep.

    Thers a 100 ways to do deco, and they all work if you spend enough time in the water in the shallow stops, but the question as to which one is the most efficient? Cleanest?

    I think that's been answered for now and its Bhulman with a step back for fitness levels.

    Despite this people are still hanging on desperately to deep stop diving despite claiming they "don't do deep stops"

    profiles like 45/75GF are a deep stop profile

    a no deep stop profile is 75/75GF

    I progressed away from deep stops over a year or two and now run 80/80 which works fine but then I started out running 20/90 and that worked fine too

    I am running 80/80 as the best available information today is this is the safest profile in comparison to say 10/125.

    I have had many a discussion with Ross over this and he puts forward some good points and some issues which border on foil hat stuff IMHO but my final word is always. Put up what ever profile you think is better and get it properly indipendantly tested.

    Then and only then will I listen

    I like 1000s listened to GUE and bubble moddel theory and in truth there was no testing to back it up except empirical testing. For many like me, the GUE stance of being hard core deep long deco divers and saying deep stops are the best, had massive influence. And they were doing 30% less deco than me and being safer???? or at least claiming to be more efficient. To this day the words of a GUE instructor rattle about in my head after I posted a dive profile. "Mark why are you doing so much deco?"

    SO having learnt my lesson I think Ill now stick to independent peer reviewed manned test data
    Variable ascent rates are now taught across all GUE classes now rather than deep stops.

    Sent from my SM-G950F using Tapatalk
    GUE Instructor

  9. #29
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    What rates do they recommend Badger

  10. #30
    Gone diving back later Vanny's Avatar
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    My ascent rate is variable at best without any training


 
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