• 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

Weighting Paradox

Discussion in 'Advanced Scuba Discussions' started by cainslie, Jan 4, 2017.

  1. The Chairman

    The Chairman Chairman of the Board

    # of Dives: I just don't log dives
    Location: Cave Country!
    55,831
    23,170
    113
    The easiest thing to move on your BC is your tank... but it's counter intuitive. Moving an aluminum tank underwater means you're moving your center of buoyancy not your of center gravity. The bottom of an aluminum tank is a bubble and not a weight. Not so when it comes to steel tanks. It's hard to get your mind around this, but it's worth it when you do. Now, let's add in a second tank band, and moving that tank becomes even less predictable. So, expect the unexpected. If you really want to figure out front/rear weighting, use some clip on weights. Once you get it right, make it permanent.
     
  2. archer1960

    archer1960 Manta Ray

    # of Dives: 50 - 99
    Location: Southern New England, USA
    572
    135
    43
    I have sinky (NOT stinky!) feet, too. 2 to 4 lb on the tank band, with the band in the top position of my BC did the trick.
     
  3. mnjhuz76

    mnjhuz76 Nassau Grouper

    # of Dives: 500 - 999
    Location: Germany - Home is where the Dom is!
    71
    20
    8
    Off Topic, but this was the key to ridding me of the lower back problems I used to experience after 10-15 minutes into every dive. Due to a less than optimal tank position I was permanently diving with a hollow back. Shifting the tank slightly towards my feet helped tremendously. Definitely nothing to underestimate...
     
  4. boat sju

    boat sju Loggerhead Turtle

    # of Dives: 200 - 499
    Location: Haslett, Michigan
    1,390
    302
    83
    Re: "duck diving" I learned it in my scuba class in 1982 and it's included in the 1981 PADI Dive Manual. You mean basic snorkeling techniques aren't even taught any more?
     
  5. boulderjohn

    boulderjohn Technical Instructor ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Boulder, CO
    25,635
    17,070
    113
    Skin diving is included in the confined water portion of the class. In that session, students are indeed taught to do a head first dive to initiate the descent for breath hold diving.

    We are not talking about breath hold diving in this thread. We are talking about scuba diving.
     
  6. Bob DBF

    Bob DBF Solo Diver

    # of Dives: I just don't log dives
    Location: NorCal
    6,497
    6,611
    113
    So there is only one way to skin a cat.

    Bob
     
  7. boulderjohn

    boulderjohn Technical Instructor ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Boulder, CO
    25,635
    17,070
    113
    I don't know what you meant by that. The reference was to what PADI teaches for descent on scuba, and the correct answer is that they teach a feet first descent. They do teach a head first descent for skin diving, but that information is not in the manual.
     
  8. boat sju

    boat sju Loggerhead Turtle

    # of Dives: 200 - 499
    Location: Haslett, Michigan
    1,390
    302
    83
    boulderjohn,

    It was in the manual, it was taught in my class, it can be used for scuba diving. So what exactly are you arguing about?
     
    Killerflyingbugs likes this.
  9. archer1960

    archer1960 Manta Ray

    # of Dives: 50 - 99
    Location: Southern New England, USA
    572
    135
    43
    It's not in the manual any more.
     
  10. chrisch

    chrisch Solo Diver

    1,062
    340
    83
    I was taught snorkel and duck dive way back when I started diving. I think Archer1960 is correct and this element is now absent from (at least PADI) training. I did a bit in the pool as part of the Divemaster I think (again a long time ago). Beyond that it has never been of any use to me whatsoever. Feet first descent is the standard and as a drysuit diver is pretty much the only option if you want to get the residual gas out the legs. Scuba diving isn't snorkelling.
     

Share This Page