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Mystery - Forward propulsion

Discussion in 'Technical Diving Specialties' started by Ghattas, Oct 21, 2019.

  1. wKkaY

    wKkaY DIR Practitioner

    # of Dives: 500 - 999
    Location: Malaysia
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    A video can reveal a lot. Here's one that I took of a reef, but it happens to capture another diver who moves very little for the amount of strokes he does.

     
  2. ajtoady

    ajtoady ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 200 - 499
    Location: Hammond, NY
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    Are you all wearing and taking the same gear? Twins, stages, lights, etc. drag is increased with each piece and could be a big factor. Also is there any way you are overweighted? With all the gear you mentioned you should be using a wing with significant lift. Any additional air in the wing and that wing drag increases proportionately.
     
    chillyinCanada likes this.
  3. Hoyden

    Hoyden Instructor, Scuba

    # of Dives: 2,500 - 4,999
    Location: Rockville, MD
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    I was forced to use Apeks RK3s at work for awhile. They weren't terrible in exhibits, but were horrible in open water.These are the softest of any of the traditional style fins I have ever tried. Scubapro Jets or OMS Slipstream may fix your issues. I have used other similar fins (Deep 6, Hollis,etc), but prefer either Jets or Slipstreams. Try to borrow a pair and see if that changes your speed.
     
    АлександрД likes this.
  4. Carl_F

    Carl_F Instructor, Scuba

    # of Dives: 500 - 999
    Location: Seneca, SC
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    @Ghattas - you mentioned two stages - if you're stages are slung like the video just a few posts back, that also contributes drag. Stages slung similar to sidemount with the tanks streamlined to your body will reduce the drag. But others have offered solutions that will likely offer larger benefit ... weighting, glide portion of the kick.
     
  5. SoFlaDiver954

    SoFlaDiver954 Nassau Grouper

    # of Dives: 200 - 499
    Location: Ft lauderdale, FL
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    With likely 3 different mixes in the slung bottles, sidemounting will make gas identification more of a task.

    I definitely think a weight check and utilizing the glide portion of the kick should be done.

    Also, dive leaders and dive masters are often hesitant to critique their paying customers. They tell you that you're awesome and maybe you'll tip better.
     
  6. Carl_F

    Carl_F Instructor, Scuba

    # of Dives: 500 - 999
    Location: Seneca, SC
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    149
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    Two stages, one left, one right ... gas ID wouldn't be an issue backmount mains or sidemount mains. Just need to ensure the neck labels are properly positioned.
     
  7. SoFlaDiver954

    SoFlaDiver954 Nassau Grouper

    # of Dives: 200 - 499
    Location: Ft lauderdale, FL
    168
    63
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    A lot of folks stack everything on the left instead of left and right. If properly sidemounted, they will need to be pulled forward and rotating is more difficult. That being said, I dont expect the stages to be the issue here.
     
  8. divezonescuba

    divezonescuba ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Houston, Texas
    1,260
    328
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    The Diverite REC model in XT material is made for backmount technical diving. You can also use it with minor modification with a single tank. It has 45 pounds of lift and can be ordered in single bladder or with a redundant bladder which is what I have.

    I have used it in salt water with 2 back mount al80s, an al80 stage, an al80 with x50, and an al40 with x100. Total of 4 al80s and one al40. I have also used it with LP85s back mounted.

    That was the configuration that I used it for both my hypoxic trimix class and later on in the hypoxic trimix instructor class both in 5mm wetsuits. No problems at all.
     
  9. Miyaru

    Miyaru Tech Instructor

    # of Dives: 2,500 - 4,999
    Location: EU
    260
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    Adding weights to counter 3 near-empty stages and and near-empty doubles?

    Another approach is to send used stages up to the surface once they become too buoyant (along your smb line). I'd choose that over taking more weight.

    As for lift: with steel doubles and 3 aluminum stages, a 45lbs wing is enough to keep me at the surface at the beginning of a dive, in salt water. In fresh water / cave I sometimes use a 60lbs wing.
    In tropical waters, using aluminum doubles and stages, a 45lbs wing and a 7mm wetsuit, I can easily stay at the surface. Steel backplate, no extra weights.
    Holding your decostop depth becomes more comfortable with less buoyancy adjustments.

    So.....what size is your wing?
    What's the weight of your backplate?
    How much lead do you take?
     

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