• 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

Trying to understand cylinder sizes

Discussion in 'Basic Scuba Discussions' started by Kirk Bauer, Oct 7, 2019.

  1. ofg-1

    ofg-1 Course Director

    270
    545
    93
    Metric system bah! We here in the US have advanced our educational system to the point that we can now confuse the crap out of poor unsuspecting children by teaching mathematics using two different systems, imperial and metric.
     
    formernuke likes this.
  2. ljpm

    ljpm Barracuda

    # of Dives: 50 - 99
    Location: Ottawa, Canada
    342
    118
    43
    Actually in metric you wouldn't have an Al80; you would have an Al11 (or Al2265). :)
     
  3. kelemvor

    kelemvor Big Fleshy Monster ScubaBoard Supporter

    # of Dives: 100 - 199
    Location: Largo, FL USA
    5,914
    3,107
    113
    I've always found the "water volume" to be confusing. Most people in the US (imperial) don't use/talk in water volume anyway. Not that the metric system inherently means you have to measure tank volume with water....

    Since you're in Atlanta, just use imperial. PSI/Cubic Feet. When you get fills or rent tanks, that's what people will use to reference things. That is, unless you're traveling outside of the US and Caribbean areas (Caribbean also seems to use imperial).

    I had a discussion on a similar topic recently in another thread. Personally, I'm not opposed to using metric, but I would use metric to measure the gas volume in the tank. not water volume. I don't want water in my tanks anyway.

    Maybe someday, I'll find a need to measure my tanks in water volume. The few tech classes I've taken did not mention it. If you frequent scubaboard for a while you will find there are a few scuba "issues" that seem to be strongly favored on scubaboard but not in the real world. Or maybe they're just popular in other parts of the real world than the ones in which I live and dive.
     
  4. Storker

    Storker Divemaster

    # of Dives: 100 - 199
    Location: close to a Hell which occasionally freezes over
    12,927
    9,341
    113
    No, as I said, you'd have an 11x200 (11L, 200 bar service pressure)

    I've always found the "surface cubic feet" to be confusing. People in metric countries don't use/talk in surface gas volume anyway :poke: (tongue firmly in cheek, trying to point out that unfamiliar units are more confusing than familiar units, no matter what you normally use)
     
  5. Bob DBF

    Bob DBF Solo Diver

    # of Dives: I just don't log dives
    Location: NorCal
    6,700
    7,091
    113
    That seems to be the crux of the controversy. The mechanics of gas planning are different, but the outcome should be the same, take the gas you need for the dive. Having used metric a lot for one job I had, I'm not afraid of it, I wouldn't have a huge problem changing to metric, however I would have an issue communicating with dive buddies about gas planning for an involved dive.

    Also it would take a while to have an intuitive understanding of the physical size of the metric measurements. Hell, I'm still trying to get used to the fact that a pint in England is bigger than in the US, I like it, but it's a change. I now try to get the US pubs to pour a proper pint.



    Bob
     
  6. Storker

    Storker Divemaster

    # of Dives: 100 - 199
    Location: close to a Hell which occasionally freezes over
    12,927
    9,341
    113
    Agreed.

    That doesn't mean that one of the systems isn't objectively superior, though :stirpot: (IMNSHO, YMMV etc)
    (D&R)
     
    Bob DBF likes this.
  7. Neilwood

    Neilwood Loggerhead Turtle

    # of Dives: 50 - 99
    Location: Scotland
    2,461
    1,515
    113
    They would have to find proper beer first.
     
    Storker likes this.
  8. JohnnyC

    JohnnyC PADI Pro

    # of Dives: I'm a Fish!
    Location: United States
    3,355
    3,700
    113
    It's because you're overthinking it (on purpose?). You're getting hung up on what you have perceived as the important aspect, the "water" part, when it's entirely material agnostic. An AL80 is 11 units big. It holds 2200 units when it's filled to what's marked on the side of the tank. You breathe 20 units per minute at the surface. An AL80 is actually 77 units, but only at what's stamped on the side of the tank. If it's different, then not only is it not the 80 units it's advertised to be, it's not even the 77 units that actually matches what's written on the tank. Easy, right?

    If I give you 10 oranges and you eat one a minute, it's pretty damn easy. If I give you 13 oranges and you eat 0.4 oranges a minute, that's stupid. If I give you a basket and tell you it holds 10 flingdingers, and it's written on the side that it holds 10 flingdingers, that's easy. If I give you a basket and tell you it holds 10 flingdingers but only under one single set of circumstances and now the circumstances aren't what's written on the basket, now tell me how many flingdingers you have.

    Using imperial volumetric measurements are effing stupid. If I can learn to dive in metric, despite a lifetime of using imperial measurements for design, engineering, and construction, there's clearly an advantage. You seem to think that the real world of technical diving favors imperial? That's absolutely not the case whatsoever. The vast vast majority of technical dives around the world are conducted in metric. In fact, the only minor crossover is Mexico, where everyone dives in metric except visiting cave divers and some US instructors who have moved south.

    If you like using imperial, that's fine, but don't try and tell people it's superior in any way because you're hung up on semantics. That's just silly.
     
  9. Bob DBF

    Bob DBF Solo Diver

    # of Dives: I just don't log dives
    Location: NorCal
    6,700
    7,091
    113
    There are a few.



    Bob
     
    Neilwood likes this.

Share This Page