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Change in buoyancy from 12l to 15l cylinder

Discussion in 'Basic Scuba Discussions' started by BlueTrin, Apr 9, 2019.

  1. Storker

    Storker Divemaster

    # of Dives: 100 - 199
    Location: close to a Hell which occasionally freezes over
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    So, the 15 weighs less than your 12 and has 3L more internal volume, and you use less lead? That just doesn't make sense to me.

    From what I'm reading here, the 15 should be more than 3kp more positive than your 12. I could take some 4-5kg off my belt when I switched from a 15L to a 10L.
     
    BurhanMuntasser likes this.
  2. BurhanMuntasser

    BurhanMuntasser Dive Charter

    # of Dives: I'm a Fish!
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    Sorry, I meant it the other way around, I use less lead with the 12L heavier than with the 15L one. I have to add more weight with the 15L tank.
     
  3. Storker

    Storker Divemaster

    # of Dives: 100 - 199
    Location: close to a Hell which occasionally freezes over
    13,237
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    Thanks. That makes sense.

    EDIT: Some 3-4kg less, amirite?
     
    BurhanMuntasser likes this.
  4. BurhanMuntasser

    BurhanMuntasser Dive Charter

    # of Dives: I'm a Fish!
    Location: Nomad
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    Somewhere around that, I don't remember exactly how much now. I am traveling away from diving unfortunately :(

    I normally use 15L and only use 12L when my 15L tanks weren't filled.
     
  5. CodeS

    CodeS Angel Fish

    # of Dives: 100 - 199
    Location: Sydney, Australia
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    I often use a 15L tank for a 2 hr dive (20-10m). This provides plenty of gas when diving a 32% mix (or more), it's nice not having to rush too much.

    I have found with my tanks that I need to add around 1kg with the 15l. I think there is some variation between tanks as my buddy doesn't change his weighting. There isn't much in it, it'll be dive-able with the same amount of weight so hop in the water and see how you go.
     
  6. Diving Dubai

    Diving Dubai Instructor, Scuba

    # of Dives: 500 - 999
    Location: Dubai UAE
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    My Faber 15's are stamped 16.5kg, my Faber 12's 13.5kg

    I throw on an additional 1kg and I'm all good (even if I forget it's no drama)
     
  7. ljpm

    ljpm Barracuda

    # of Dives: 50 - 99
    Location: Ottawa, Canada
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    I'm in Canada so I tried to convert to metric for this thread. Seems I may not have gotten it quite right. There are so many conversions on line it is confusing.

    Seems the conversions I was using were a bit off. I actually use a 133 cubic ft. tank. According to this chart it is a 17L tank. I'm not sure how that fits in with other previous chart. That chart lists an 18L as 150 cubic ft. and this one has it at 19L.

    When I switched from an Al 80 (11L?) to the 133 I lost 7lbs of lead. That almost made up for the additional weight of the tank. The only real difference I have found using the 133 is I have to start the dive 2lbs heavier than I normally would or I wont be able to hold the safety stop. The Al 80 holds about 6.5 lbs of air and the 133 holds about 10.5 lbs.


    Faber-Cylinder-Specifications.jpg
     
  8. BlueTrin

    BlueTrin DIR Practitioner

    # of Dives: 100 - 199
    Location: London
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    That’s what I did (using the same weight) and I was surprised that it was that straightforward and this is why I asked here, but I guess it makes sense as you only look at the buoyancy.
     
  9. Jcp2

    Jcp2 Literally virtual ScubaBoard Supporter

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    rsingler likes this.
  10. RyanT

    RyanT Solo Diver

    # of Dives: 500 - 999
    Location: Maryland
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    Now, I'm suspicious @Storker. You say English isn't your first language but it sure seems like "southern US" english is in your command.
     

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