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Steel LP85 doubles way too negative

Discussion in 'Tanks, Valves and Bands' started by ahcalde, Dec 28, 2019.

  1. rhwestfall

    rhwestfall Solo Diver

    # of Dives: 200 - 499
    Location: "La Grande Ile"
    12,772
    11,732
    113
    agree, but vintage 72's excluded from this statement..
     
    couv likes this.
  2. W W Meixner

    W W Meixner Rebreather Pilot

    # of Dives: 500 - 999
    Location: Ontario Canada
    794
    541
    93
    AH...

    Diving with steel doubles...HP/LP like everything thing else we learn...is an acquired skill...

    Doubles are negative...plain and simple...even with a properly fitting dry-suit...

    I think what's lacking in your case is the instruction you received...and time to acquire the skill..

    Mastering your doubles will come with practice...if you have access to a deep ended pool it will come quicker...

    Balance and stability has a lot to do with your harness...comfort/adjustment capabilities...and your wing...

    I'm currently diving with HP 117's...OMS IQ pack harness/AL BP...60 pound lift bungee'd OMS wing...and full time dry-suit...no ballast...a little cumbersome on the surface...but in the water...the weight disappears...the OMS IQ pack keeps the cylinders snuggly positioned while remaining comfortable...

    If you're diving heavy doubles with a wet suit...you may want to consider a double bladder wing...

    I certainly wouldn't be considering swapping out what you have...for 3AL 80's...that's going backwards...

    All the best with your new doubles...you'll be performing barrel rolls and somersaults in no time...

    W.W...
     
    rsingler likes this.
  3. doctormike

    doctormike ScubaBoard Supporter Staff Member ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: New York City
    6,353
    6,008
    113
    Steel doubles and a heavy wetsuit is just a bad combination. It's one of the few configurations where I would be concerned about an unbalanced rig. That's actually the reason why I bought a double bladder wing (don't use it any more).
     
  4. ofg-1

    ofg-1 Course Director

    269
    541
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    get an aluminum or ABS backplate for the wetsuit with doubles. See if you can borrow one and try it.
     
    Caveeagle likes this.
  5. divezonescuba

    divezonescuba ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Houston, Texas
    1,300
    366
    83
    The bouyancy characteristics between the LP85s and HP100s look significantly different. I also don’t like to have to put more than 3250 hot into tanks from my compressor.

    When I fill HP100s, I have to pump up to 3600, cool, pump up to 3600 to get 3442.
     
  6. tbone1004

    tbone1004 ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: I'm a Fish!
    Location: Greenville, South Carolina, United States
    15,885
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    The LP85's and FX100's are functionally identical. The LP85's hold 13L, the FX100's hold 12.9L, basically the same thing. At 2640psi, the LP85's hold 85cf, and the 100's hold 84.3 ish. At 3250, they're 104.6 and 103.8.
    The FX100's have the advantage of being a "normal" diameter so you don't have to adjust cam bands, won't get short fills if you take it to another dive shop, can come in galvanized, and you can take 3lbs off of your weight belt if you have any. I'd only get the LP85's if that 3lbs of negative buoyancy pushes you to being dangerously overweight, AND you can guarantee that you will always get reasonable fills.
     
  7. Caveeagle

    Caveeagle Rebreather Pilot

    # of Dives: 500 - 999
    Location: High Springs, FL
    1,533
    1,029
    113
    that is exactly what I dove back in the 90s. With a 7mm farmer John, and double 95s, we also used a 4# drop weight at the start and end of the dive.
     

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