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Rise and Fall of the Bubble (Model) ?

Discussion in 'Ask Dr. Decompression' started by Roger Hobden, Sep 25, 2018.

  1. uncfnp

    uncfnp Solo Diver

    # of Dives: 500 - 999
    Location: North Carolina
    Are we throwing out the baby with the bath water? Just because deep stops for decompression diving did not prove to be the darling that was expected is it time to completely eliminate the entire model? Why does it seem that at the same time recreational dive computers with adapted Buhlmann algorithms seem to be incorporating some of the bubble model concepts (from an uninformed layman’s perspective).
  2. Storker

    Storker Divemaster

    # of Dives: 100 - 199
    Location: close to a Hell which occasionally freezes over
    Does it seem so?
  3. sigxbill

    sigxbill Tech Instructor

    The point of this discussion should be to seek truth. The problem is that when some become invested exploring a particular path, proving that path to be correct sometimes becomes personal. I think this may be true for many who have invested in Shaerwaters and have been experimenting on themselves via GF's. This would later prove inflammatory to Ross.

    Ross has developed software that calculates both bubble and dissolved gas models - so he has no reason to argue one over the other. Since he converted both algorithms into software, Ross has the advantage of having compared and contrasted the details of their mathematics on a more detailed scale than the rest of us. He has undoubtedly developed a unique perspective that I found interesting in my persuit of truth. I'm not sure what Ross wrote that caused his banishment, but short of physical threats, I think we are all adults here and should be able to handle a little bit of criticism - even from Ross. We are all human though, and unfortunately from Ross' truth seeking perspective, he may have felt overwhelmingly attacked in his refusal to acquiesce that Buhlmann was right - and overreacted to the popular mob's criticism. The question is, as a truth seeking group, how should we deal with mob style criticism in our forum?

    The NEDU study seems to be the primary evidence used to suggest Buhlmann was right and VPN is wrong. The problem is that many of us that don't dive the way the NEDU study was designed, so applying it's findings to us may or may not be valid. Regarding SM, he primarily comments on NEDU (just like Ross) but was not part of the study. Other issues include the fact that we are primarily arguing Buhlmann vs VPM, but the Navy uses Thalmann - LOL! And the fact that no one is using straight Buhlmann without GF's suggests Buhlmann wasn't right either. If someone developed an arbitrary math overlay of VPM to make it's ascent curve match what the NEDU study suggests it should look like, that wouldn't magically make VPM right either; that would simply be the same thing as GF's over Buhlmann.

    Personally I seek truth, and have no preference which one is right. Ross represented interesting counter arguments to the popular forgone conclusion that Buhlmann was right. Which one is right is not as visibly clear as a round vs flat earth. Maybe there is another option that science hasn't yet considered.

  4. Storker

    Storker Divemaster

    # of Dives: 100 - 199
    Location: close to a Hell which occasionally freezes over
    Doesn't help to have studied the maths of it if you completely lack any kind of understanding of the physiology that the math describes. Or completely refuse to accept said physiology.

    Which Ross repeatedly demonstrated.
    shoredivr, rjack321 and tridacna like this.
  5. TrimixToo

    TrimixToo Regular of the Pub

    # of Dives: 200 - 499
    Location: New York State
    I will not go into detail, but in my view the charges he repeatedly leveled against those doing the actual science were a lot more serious than "a little bit of criticism." I am all for healthy debate. This was not healthy debate. You can likely find the threads elsewhere (I think the mods appropriately defenestrated the worst of the threads' content) to show you want I mean, as they might persist on other forums. Simon, in particular, demonstrated as much patience as a saint should ever be called upon to demonstrate, but clearly even he has his limit--and at that limit he restrained himself admirably.

    Just my 2 PSI.
  6. tursiops

    tursiops Marine Scientist and Master Instructor ScubaBoard Supporter

    # of Dives: 2,500 - 4,999
    Location: U.S. East Coast
    The problem with Ross's arguments were partly in content and partly in presentation. He was seeking to show that everyone else was wrong, but could only use specious, silly, and blatantly wrong arguments to support his case. And it did not help that he constantly resorted to unsubstantiated personal attacks when cornered.

    And, @sigxbill, your comment that DD is not credible because he works for the goverment is WAY out of line, is the worst kind of personal attack, and you should apologize for it.
  7. leadduck

    leadduck Barracuda

    I don't think that Ross developed the software that calculates the bubble model, but that he just put a graphical user interface on top of Erik Baker's VPM-B code, that was V-Planner. In his many comments on this forum I got the deep impression that Ross' expertise is only on the Windows user interface programming, and iOS and Android app programming, but that he didn't understand neither the math behind the decompression models nor the physiology of decompression at all.
  8. sigxbill

    sigxbill Tech Instructor

    @tursiops - you are right - I wasn’t thinking of it as personal - my bad

  9. Roger Hobden

    Roger Hobden Barracuda

    # of Dives: 50 - 99
    Location: Montreal
    All this is relatively new to me, compared to the experts on SB that have orders of magnitude more experience and knowledge then myself about these issues.

    I do have a question, however: when the NEDU design protocol was made available, did the people who are convinced that deep stops have some value contribute to the methodology used in the study before the study was done ? Or was the methodology only made public after the fact ?
  10. tridacna

    tridacna ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 2,500 - 4,999
    Location: New Jersey
    Defenestration. Argument over. Yeah!
    shoredivr likes this.

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