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Wisdom of trusting one's dive computer?

Discussion in 'Basic Scuba Discussions' started by CaveSloth, Nov 12, 2019.

  1. FreeFlyFreak

    FreeFlyFreak Solo Diver

    # of Dives: 25 - 49
    Location: California
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    Huh?
    What you said makes no sense other than that running out of NDL is comparable to running out of gas.

    Rolling the dice would be not doing required deco after already F'king up once.
    The computer requires XX/YY regardless of Rec or Tec setting, you have to set both GFLo and GFHi, it is not optional. I only gave the reason why it is required.
     
  2. doctormike

    doctormike ScubaBoard Supporter Staff Member ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: New York City
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    When in recreational mode, the Teric has three levels of conservatism:

    Low (45/95)
    Med (40/85)
    High (35/75)

    In Tec mode, you can set the GFLo and GFHi to whatever combination you want.

    There is by definition some number representing GFLo in the Teric's decompression algorithm, the fact that on any particular dive you don't exceed NDL doesn't mean that the variable doesn't exist. It just means that you don't incur enough inert gas loading to require a deco stop. But those two points still determine the slope of the ceiling line, and exist somewhere in the computer's settings (default, standardized or customized).

    The computer has no way of knowing whether or not you are going to go into deco, so it will continually make calculations based on your current tissue loading and generate a stop if your profile means that you cross that ceiling line..


    Shearwater_GF_graph.jpg
     
    CaveSloth, drrich2 and FreeFlyFreak like this.
  3. JohnN

    JohnN Solo Diver

    # of Dives: 200 - 499
    Location: Oar--eee---gun
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    And I disagree, spinning the cylinder is when you compound one screwup (incurring a deco obligation on what should be a NDL dive) by using a very aggressive decompression profile.
     
  4. FreeFlyFreak

    FreeFlyFreak Solo Diver

    # of Dives: 25 - 49
    Location: California
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    Then we agree to disagree.
    If I am happy at 85% at the surface, I am happy at 85% in the water.
    Unless its cold in which case I am happy at 75%

    Like I said, its a personal decision. I have made mine, you have made yours. Dive and let dive.
    Its called personal responsibility.

    I have never run out of gas in a car, in an aircraft, or in the water, but I suppose there could always be a first time. Somehow I doubt i'll run out of NDL and have to "roll the dice" regardless of the numbers I chose after much study to set.
     
  5. doctormike

    doctormike ScubaBoard Supporter Staff Member ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: New York City
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    Well, it may be your personal decision, there is no scuba police, but the whole point of these discussions is that we actually discuss things. Sometimes we reconsider our previous practices when someone makes a good point, and change what we do. I sure have done that. If the answer to everything is "dive and let dive", why bother?

    Also, some of us feel the need to call out what we see as unsafe diving practices, because lots of diver - new divers - read these threads. I'm not saying that's what you are promoting, but I'm actually having a hard time understanding what you are recommending.

    Are you saying that one should make the variables of the recreational algorithm more aggressive, so that if a recreational diver goes into deco, they will have increased decompression stress?
     
    johndiver999 likes this.
  6. FreeFlyFreak

    FreeFlyFreak Solo Diver

    # of Dives: 25 - 49
    Location: California
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    No, I am not "suggesting" or "recommending" anything.
    I am posting my settings.
    I am happy with them, others may not be.
    But if I somehow (doubtfully) over stay my NDL by a few minutes at the depths I dive, I doubt whether it will make a difference if I set 30/85
    Or 85/85 in terms of my stop depth. I have looked at the numbers.
    If 85 or 75 is good at the surface it is good at 10 or 20 ft AFAIAC

    Everyone can jump all over me IRDGAS.

    Discussion is good.
    Disagreement is good.
    Personal responsibility is good.

    Sorry for getting the thread off track.
    Enjoy your previously scheduled entertainment.
     
  7. CaveSloth

    CaveSloth Barracuda

    # of Dives: 50 - 99
    Location: The Deep South
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    @doctormike you gave some really good info... Take er home and explain how / why one should choose their conservatism settings so I don't have to spend hours watching YouTube videos.

    Is there a calculator anywhere for suggesting GFLo and GFHi settings based on whatever factors? (water temp, BMI, aversion to risk, etc...?)
     
  8. Fastmarc

    Fastmarc Just drifting along... ScubaBoard Supporter

    # of Dives: 200 - 499
    Location: Kingston, Jamaica
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    Interestingly, Mares medium conservative setting is 85/85.

    EDIT: MARES GENIUS
     
  9. hroark2112

    hroark2112 Tech Instructor

    # of Dives: 0 - 24
    Location: Raleigh, NC
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    If you’ve been diving 30//70 and you’ve never gone into deco, and you’ve never had any symptoms of DCS, continue diving 30/70. The differences in the profile are minimal and it’s not worth the risk. It’s working for you, why change it?

    Until such time that you really understand deco theory and GF’s, stick with what’s working. If you’re interested in learning, DO NOT go down the rabbit hole of YouTube videos to learn. Get a legit book like Deco For Divers and read it. It’s an excellent book and you’ll learn a lot.
     
    VE7DAC, rjack321 and RyanT like this.
  10. Manatee Diver

    Manatee Diver Manta Ray

    # of Dives: None - Not Certified
    Location: Tampa Bay, FL
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    Deco for Divers really needs an update, as it still mentions Bubble Model and Deep Stops as being good things.

    Beyond that I found it easy to understand.
     
    FreeFlyFreak and RyanT like this.

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