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Reverse dive profile advice

Discussion in 'Advanced Scuba Discussions' started by epolice, Feb 1, 2020.

  1. scubadada

    scubadada Diver Staff Member ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Philadelphia and Boynton Beach
    11,989
    7,742
    113
    Hi @epolice

    I assume you will continue to dive as you have been diving a couple of years and are traveling to Bonaiire.

    The easiest way for you to increase your enjoyment with profiles like you plan for Bonaire would be to:
    1) Get nitrox certified. You can do this online with a brief visit to your LDS or simply spend a little time with your operator in Bonaire.
    2) Buy a simple dive computer to give you multilevel credit on your nitrox dives. Use the NDL planner to give you an idea of the no stop time on your next dive following your surface

    If you are interested, consider calculating your RMV, there are simple calculators available RMV Rate Calculator. SAC Rate Calculator. How much gas do you use? How to calculate RMV and SAC.. Knowing your gas consumption will also help planning your dives.
     
  2. JoeFriday

    JoeFriday Photographer

    346
    219
    43
    Have we been ignoring the OPs profile hints? And hence answering a different question?

    We know:
    - Bonaire shore dives
    - dive 1 to 45 feet max for less than 1/2 of the dive
    - dive 2 to 75 feet max for less than 1/2 of the dive.
    - 75 minute si

    The only missing bit of maybe relevant info is:
    - do they plan to surface swim to the marker buoy or are they starting a leisurely dive as soon as they can submerge?

    Based on the info given I assume the OP is using the standard vacation diver rule of half's.

    The surface swim can have a negative impact as they can get to depth much quicker. If they submerge immediately with no surface swim it will take 5 to 10 minutes to swim out to reach max depth, depending on if they stop to look at things on the way out.

    The last half of each dive can easily be spent above 30 feet. Maybe even as shallow as 15 feet or less.

    So far the answers have assumed worst case. Anyone have predictions on the results of a more realistic conservative profile?
     
  3. ChuckP

    ChuckP Manta Ray

    # of Dives: 200 - 499
    Location: Cozumel
    898
    686
    93
    While the lure of Bonaire and curaçao are constant on your own diving - for me it’s scary to think of a diver doing this trip on their own without a great understanding of either their computer or tables - I was there once. Add to the risk the hot shower after your fifth dive of the day cause you’re shivering........

    Best bet, get a computer, understand the diving and planning functions.
     
  4. tursiops

    tursiops Marine Scientist and Master Instructor ScubaBoard Supporter

    # of Dives: 2,500 - 4,999
    Location: U.S. East Coast
    9,293
    6,988
    113
    AfterDark likes this.
  5. tursiops

    tursiops Marine Scientist and Master Instructor ScubaBoard Supporter

    # of Dives: 2,500 - 4,999
    Location: U.S. East Coast
    9,293
    6,988
    113
    See Post #10.
     
  6. mac64

    mac64 Barracuda

    # of Dives: 5,000 - ∞
    Location: Ireland
    388
    186
    43
    After 25 minutes at 50 feet if he did back flips up and down the beach it wouldn’t make a difference to a 70 minute interval he’s only getting 5 minutes credit..
     
  7. tursiops

    tursiops Marine Scientist and Master Instructor ScubaBoard Supporter

    # of Dives: 2,500 - 4,999
    Location: U.S. East Coast
    9,293
    6,988
    113
    The point is that your N2 comes out of solution TOO quickly and you risk DCS if you exercise immediately post-dive. Nothing to do witth getting longer second dives....
     
    AfterDark likes this.
  8. fsardone

    fsardone Solo Diver ScubaBoard Supporter

    # of Dives: I just don't log dives
    Location: Rome, Italy
    495
    472
    63
    Physical activity can create depression due to cavitation in moving joints, these might attract gas that would otherwise be carried out (albeit more slowly due to the low perfusion of the cartilage in the joints) by the blood stream. Once in gaseous state it becomes difficult to remove the bubbles.

    Now it would be good to have a nice idea of how long it would take to go back to the gym with a risk not over the usual.
     
  9. mac64

    mac64 Barracuda

    # of Dives: 5,000 - ∞
    Location: Ireland
    388
    186
    43
     
  10. fsardone

    fsardone Solo Diver ScubaBoard Supporter

    # of Dives: I just don't log dives
    Location: Rome, Italy
    495
    472
    63
    Actually joint cavitation can happen even if not diving. But if you have been diving then rather than filling with synovial fluid at the end of the mechanical cause creating the cavity it fill with gas coming out of the synovial fluid itself and not going back in.


    Cheers
     

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