• Welcome to ScubaBoard


  1. Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

    Benefits of registering include

    • Ability to post and comment on topics and discussions.
    • A Free photo gallery to share your dive photos with the world.
    • You can make this box go away

    Joining is quick and easy. Login or Register now by clicking on the button

How does your computer handle deep dives?

Discussion in 'Advanced Scuba' started by fisherdvm, Sep 23, 2018.

  1. DanielRJones

    DanielRJones Contributor

    # of Dives: 100 - 199
    Location: Uk
    251
    149
    All are displayed on the middle line. Deep stops that are not deco will show as a small writing on the very left side. Deco stops will show as full writing on the left followed by stop duration and total time to surface. Total time to surface is a bit incorrect as this adds in the standard safety stop. I have locked one of these computers out a few times (doing accelerated deco)
    The computer can handle gas switches but due to not knowing the algorithm i cannot olan to the computer. Deep stops are normally added at 16m
     
  2. fisherdvm

    fisherdvm Contributor

    # of Dives: 200 - 499
    Location:
    3,577
    47
    Like you said .... it was pretty clear when you understand the deco takes place at 10 feet plus or minus 2. In the early mandatory deco mode, there is a half depth stop of 2 or 3 minutes, as best as I recall. Once that early mandatory deco limit is passed - the air supply factor kicks in. And you are obliged to do only one deco stop at 10 ft. The deco clock does not appear until you are between 12 and 8 feet. It went up to 38 minutes and the alarm beeps at the surface for about a minute. Good thing there is an air supply logic built into a recreational computer, likely for an 80 cf single tank and average or slightly below average sac.
     
  3. fisherdvm

    fisherdvm Contributor

    # of Dives: 200 - 499
    Location:
    3,577
    47
    It took me 3 dives to figure out their logics and the screen. The guide could have been written much better.
     
  4. fisherdvm

    fisherdvm Contributor

    # of Dives: 200 - 499
    Location:
    3,577
    47
    The short mandatory deco was forgiven, and I was allowed to do the second dive. I am not sure doing the 38 minutes second mandatory deco would have been forgiven. Never know, as no dive boats would wait for 1 hr 40 min.
     
  5. DanielRJones

    DanielRJones Contributor

    # of Dives: 100 - 199
    Location: Uk
    251
    149
    There is no air supply logic. A computer does not know what you have or care what you have
     
    JohnnyC and soggybadger like this.
  6. tursiops

    tursiops Marine Scientist and Master Instructor ScubaBoard Supporter

    # of Dives: 2,500 - 4,999
    Location: U.S. East Coast
    12,149
    10,094
    This post is nonsense, full of misinderstood and made-up stuff.
     
  7. fisherdvm

    fisherdvm Contributor

    # of Dives: 200 - 499
    Location:
    3,577
    47
  8. fisherdvm

    fisherdvm Contributor

    # of Dives: 200 - 499
    Location:
    3,577
    47
    Each computer is very distinct... some will factor in the air supply. Deco stop can be either at 20 ft or at 10 ft:

    The Conclusions

    All of the computers compared (and their siblings) are equally useful for decompression-stop diving. One cannot make a decision about which is most conservative simply by comparing them during a dive at one way point alone.

    Because a computer gives you a mathematician’s idea of what might be happening to your body using model tissues rather than your own blood, skin, and bones, using one is an act of faith. You have to believe what the computer tells you. And you have to realize there is no way of knowing how close you come, each time you dive, to a decompression illness.

    When using a computer, it’s your choice whether you make additional shallow water stops or surface when your computer clears the last stop from its display and reverts to no-stop diving mode.

    However, we suggest that if you have a Group F computer, add optional conservatism (up to 50 percent is available) before undertaking this sort of diving. Those using Group E computers might do well to use them in “condition hard” mode rather than lesscautious “condition normal.”

    If you use a Group B computer and dive with a buddy who uses a Group C or D model, you might adapt the algorithm by selecting an “Altitude 1” setting rather than “Altitude 0.”

    Group C computer-users should note that their devices are not as cautious as others when used for a single dive.

    Group A computer users should take heed of the additional and optional 3 min. safety stop offered between 16 and 30 feet (ST3 to ST1) on no-stop dives and perhaps add a similar safety stop to deco-stop dives.

    Group D computer users should be sure to reserve enough air for the lengthy stops at 10 feet that might be required and have the necessary buoyancy control at that depth to be able to do the stop comfortably.
     
  9. fisherdvm

    fisherdvm Contributor

    # of Dives: 200 - 499
    Location:
    3,577
    47
    Apparently the mares puck is in the group D: ""Group D computer users should be sure to reserve enough air for the lengthy stops at 10 feet that might be required and have the necessary buoyancy control at that depth to be able to do the stop comfortably.""
     
  10. fisherdvm

    fisherdvm Contributor

    # of Dives: 200 - 499
    Location:
    3,577
    47
    You are a master instructor, and you can not explain to a diver how his computer work?? And why it makes 10 ft safety stop instead of 20 or 15??
    All have flamed me, and yet... the Master Instructor can not answer a simple question without putting others down??

    What right do you have to do that??

    Qualification because you are a scientist?
     

Share This Page