semi submersed kayak

Discussion in 'Hydrodynamics and Aerodynamics' started by Gabianni, May 16, 2014.

  1. Gabianni
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    Gabianni New Member

    would a kayak hull create less drag if you were able to lets say,find a way to ballast safely and submerse the first 3rd of the hull?
    do submarines travel faster underwater because no bow wave?
     
  2. Rastapop
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    Rastapop Naval Architect

    No.

    Yes, at high speed that's a significant reduction in drag.
     
  3. upchurchmr
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    upchurchmr Senior Member

    Submarines only get less drag when they are completely underwater, without being close to the surface.

    Take a look at a modern sub on the surface, the wake is 3 times as wide as the boat starting at about the conning tower. Huge drag on the surface and that is when they are 90% (or more) underwater.
     
  4. Gabianni
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    Gabianni New Member

    I see

    Thanks.
    It's all clear now.
    G
     
  5. gonzo
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    gonzo Senior Member

    Proper kayaks are at least 1/2 submerged. The plastic fat things they sell at major stores have little in common with what the Northern people designed and used.
     
  6. upchurchmr
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    upchurchmr Senior Member

    So what does that have to do with drag on a submersible kayak?

    Green is a pretty color - just a pertinent as "proper kayaks".

    Your proper kayaks rotted pretty fast. I really wouldn't want one.

    Much as I don't like plastic SOTs, a Surf Ski has little to do with "Proper Kayaks" also. And I rather admire them.
     
  7. Squidly-Diddly
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    Squidly-Diddly Senior Member

    My most posted link.

    WW2 German 'semi-submersible'

    http://strangevehicles.greyfalcon.us/VS 5.htm

    I could almost see this working for a 'cargo kayak' with enough weight in the hull vs human's torso. Maybe a pedal/prop powered semi-sub.

    But with 'semi-submersible' you got other issues, like trim.

    But I do notice a kayak will slow down a lot on anything except glassy smooth water and a semi-sub might help that.

    How about a Swath 'kayak'?
     
  8. Gabianni
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    Gabianni New Member

    stability vs hull shape/drag

    a k1 kayak being 5.29M long with No width restrictions......newest ones are like 40cm wide, low volume, but very unstable...the faster paddlers can easily hit 12kph if not more than that on flat water cruising speed..almost planing during the sprints.. but way too unstable
     
  9. rwatson
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    rwatson Senior Member


    Try the other extreme - the Flyak


    "The Flyak is a hydrofoil adaptation to the conventional kayak. It uses twin hydrofoils designed to raise the hull out of the water to increase the speed. Speeds of up to 27.2 km/h (7.6 m·s−1, 16.9 mph) can be achieved on calm water."
     

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  10. Gabianni
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    Gabianni New Member

    Thanks. I know of that model. The amount if energy required to "fly" the hull puts it out of reach of most of us.
    Physics is a b...h
    I guess it comes down to a tradeoff between stability vs. Drag.
    No doubt, the elite paddlers would benefit the most from tweaks.
    I was even thinking about a very low displacement hull with dare I say outrigger life mini floats that skirt/hop over the water till seconday stabiluty cones into play
     

  11. bpw
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    bpw Senior Member


    Depends on which northern cultures you are talking about, the Aleutian island kayaks are much higher volume than Greenland type, and better open water boats for it.
     
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