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Multilevel diving and rock bottom.

Discussion in 'DIR' started by amascuba, Oct 17, 2008.

  1. pengwe

    pengwe Solo Diver

    # of Dives: 100 - 199
    Location: Australia
    147
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    What kind of SAC rates does everyone use for calculating Minimum Gas? I go by what I was taught in class, but they are pretty generous. Do those of you who know you have good air consumption adjust the Rock Bottom amount to fit your usage?
     
  2. TSandM

    TSandM Missed and loved by many. Rest in Peace ScubaBoard Supporter

    36,349
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    No, I still use 2 cfm/minute, because I know my stressed SAC rate can get up to about .7, and I don't necessarily know my buddy's.
     
  3. Blackwood

    Blackwood DIR Practitioner

    # of Dives: None - Not Certified
    Location: Southern California
    5,535
    318
    83
    I know some teams who do. We don't. Like TS&M, we use 2.
     
  4. RTodd

    RTodd Manta Ray

    # of Dives: 1,000 - 2,499
    Location: Houston
    876
    22
    18
    I didn't know GUE even recommeded one. 2 is a good guide though. For almost all of my open water diving buddies (single tank, no deco), I use 1. Keep in mind that for that kind of dive you have the worst case option of accelerating stop times. I would generally use 1 for a doubles deco dive. However, I would also pad the gas for other contingencies such as water temp, conditions, amount of deco, etc. on a dive like that so there isn't a set rule for me at least.
     
  5. rjack321

    rjack321 ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Port Orchard, WA
    10,141
    4,465
    113
    For recreational with a new buddy, 2 (for both of us). I know mine doesn't get horrendous, but I have no idea about theirs.

    For deco dives with my regular buddies I use either 1.5 or 2. There comes a point, if you still think your combined consumption would be 2cf/min at 200ft, you should really evaluate whether you should do that dive.
     
  6. Peter Guy

    Peter Guy Divemaster

    # of Dives: 1,000 - 2,499
    Location: Olympia, WA
    4,296
    1,909
    113
    Lynne, when you write you use a 2cfm SAC rate do you mean a SAC of 2cfm per diver or are you using the 1cfm PER DIVER which is 2cfm for the calculations for thee and me?

    My recollection is that you use 1cfm PER DIVER.
     
  7. Gombessa

    Gombessa DIR Practitioner

    # of Dives: 200 - 499
    Location: NorCal
    4,436
    225
    63
    I think she's saying 4cfm total. 0.5 stressed for her, 3.5 stressed for you :D
     
  8. CompuDude

    CompuDude Divemaster

    # of Dives: 200 - 499
    Location: Studio City, CA, USA
    4,238
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    That's what I use. 1cfm per diver. Assuming I'm not the OOA diver, I figure my SAC will be < 1.0, and theirs will be a bit > 1.0, and between the two, it'll hit around 2.0.
     
  9. dsteding

    dsteding DIR Practitioner

    # of Dives: 200 - 499
    Location: Seattle, downtown
    1,074
    2
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    That is too high for Lynne and too low for Peter.
     
  10. TSandM

    TSandM Missed and loved by many. Rest in Peace ScubaBoard Supporter

    36,349
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    Okay, okay; 1 cfm PER DIVER, yes.

    And my SAC rate during air-sharing is probably higher than that, because I'm so ticked off that all the people I dive with seem to run out of air ALL THE TIME! :D
     

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