• 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

Bouyancy Calculator

Discussion in 'Underwater Videography' started by dbramley, Oct 3, 2007.

  1. dbramley

    dbramley Solo Diver

    40
    0
    Just got a Gates and Z1U, with custom HID lights and battery backs came out to be 8 lbs neg. I found this helpful link from Mainland Robotics team which made it very easy to find the length PVC tube for my bouyancy adjustment. I have a fish scale I travel with so I can weigh my bags. I just put the camera in the water with batteries etc and got 8 lbs. Punch that into the excel spread sheet program, tell them what diameter tube you want to use and there you go.

    Dan

    www.geocities.com/mainlandrobotics/buoyancy_calc.xls
     
  2. ronscuba

    ronscuba Contributor

    # of Dives: 500 - 999
    Location: NYC
    2,847
    571
    That's a cool program. Looks like you'll need a big PVC tube or move the battery packs to your BCD.
     
  3. Video rookie

    Video rookie Contributor

    # of Dives: 50 - 99
    Location: Azle, TX
    114
    0
    Which fish scale are you using? I have one that is basically useless for buoyance calculations, since it measures in 2lb increments, and would like to get one that would measure more accurately. I saw one at Ace hardware, and I think it went up to 20lbs. Anyone find a reasonably priced "fish" type scale they would recommend?

    Thanks,
    Vic
     
  4. ronscuba

    ronscuba Contributor

    # of Dives: 500 - 999
    Location: NYC
    2,847
    571
  5. crpntr133

    crpntr133 lost, even with a compass

    # of Dives: 100 - 199
    Location: West Central Indiana
    6,194
    12

    Am I missing something with being that consumed by the buoyancy of my rig? Within 1lb is getting pretty close. The salinity of the water can change it close to that. I realize that you don't want it way off but within in 1lb should be good enough.
     
  6. ronscuba

    ronscuba Contributor

    # of Dives: 500 - 999
    Location: NYC
    2,847
    571
    Guess it depends on what you are filming.

    For normal shooting, 1lb doesn't matter, but when I shoot macro subjects and I zoom to fill the frame and I have to hover totally still for 15 seconds plus with my rig held out in front of me, 1 lb negative makes a difference.

    It's a personal thing. Some people like slightly positive, some slightly negative, I try to get my rig as close to neutral as possible.

    Just my 2 cents.
     
  7. HiDefPics

    HiDefPics Contributor

    # of Dives: 200 - 499
    Location: Indianapolis, IN
    116
    0
    Thanks for posting that spreadsheet. I'm shooting with the same rig + the SWP44 port, which adds more weight to the front. It's been trial and error to balance it out. This should help.
     
  8. dbramley

    dbramley Solo Diver

    40
    0
    For me one pound is a huge deal. At 185ft in local lake (interpret that black water) the less I have to wrestle the better. The large 3" tube worked great. I got some killer footage of an old hydroelectric generator house and large butterfly valves which was on the backside of an old dam which is now submerged. I am at work so I don't have the name of the scale but I will check and post when I get home. The scale measures in 1/10 of a pound. I have not tried to calibrate it with a known weight however.
     
  9. dbramley

    dbramley Solo Diver

    40
    0
    For me one pound is a huge deal. At 185ft in local lake (interpret that black water) the less I have to wrestle the better. The large 3" tubes worked great. I got some killer footage of an old hydroelectric generator house and large butterfly valves which was on the backside of an old dam which is now submerged. I am at work so I don't have the name of the scale but I will check and post when I get home. The scale measures in 1/10 of a pound. I have not tried to calibrate it with a known weight however.
     
  10. dbramley

    dbramley Solo Diver

    40
    0
    OOps, sorry for the double post
     

Share This Page