Fore & aft centerboard sliding system

Discussion in 'Sailboats' started by heycaptaingg, Aug 9, 2021.

  1. heycaptaingg
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    heycaptaingg New Member

    Hey all, I'm looking for systems to move a (dinghy) centerboard (or foils) fore and aft during sailing.
     
  2. Blueknarr
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    Blueknarr Senior Member

    Simply pivot the center board slightly to achieve a different point of lateral resistance
     
  3. heycaptaingg
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    heycaptaingg New Member

    Thanks Blueknarr, My goal is to be able to slide the complete daggerboard case fore and aft.
    upload_2021-8-9_16-41-11.png
     
  4. DCockey
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    DCockey Senior Member

    For a daggerboard (rather than a centerboard with a pivot) build a long case and just slide the board fore/aft as desired. It will be difficult or impossible to move the board while sailing on any course other than downwind run due to side force binding the board in the case. Also be aware that the longer slot will add drag.
     
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  5. Blueknarr
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    Blueknarr Senior Member

    Sliding either a dagger or center board case involves a nightmare of water integrity issues.
     
  6. DCockey
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    DCockey Senior Member

    What water integrity issues would be caused by extending a dagger board case and slot fore aft? What would be different than if the case slot were not extended?
     
  7. Blueknarr
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    Blueknarr Senior Member

    No issues with sliding a board within a case with an extended slot
    But the op's desire to have a sliding case is scary.
     
  8. DCockey
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    DCockey Senior Member

    Agree, moving the actual case is not practical.
     
  9. upchurchmr
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    upchurchmr Senior Member

    There was a famous (I don't remember the name) kayak sailor who used a sliding centerboard instead of a rudder. He made it 1000's of miles down into the carribean successfully. The boat is in a museum somewhere up north.

    Sorry that is so vague - someone will know what I am talking about.
     
  10. wet feet
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    wet feet Senior Member


    The name Fenger comes to mind.

    I have seen a sliding centreboard system on a Flying Dutchman a long time ago and somebody with more knowledge of the class than I have may be able to provide details.The whole concept reminds me of the man who planned a sailing speed record boat that used a sliding rig base to adjust the rig in order to lose the drag of a rudder.I suspect the complication and weight of the system slowed the boat much more than a well made rudder would have.In the same vein,I would expect a mast step with provision to move the mast heel would eliminate the need to engineer a complicated system.It isn't hugely difficult to visualise the concept,but creating a system that would work under load is a challenge.
     
  11. upchurchmr
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    upchurchmr Senior Member

  12. heycaptaingg
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    heycaptaingg New Member

    Thanks. I was looking for a more modern setup ;-) My inspiration comes from Rogers minitransat 3D keel design, where the canting keel could also be moved fore and aft Rogers Yacht Design : info@rogersyachtdesign.com http://www.rogersyachtdesign.com/sections/transat.html
    Sorry if I was not clear, I just want to move the daggerboard longitudinaly, not the complete case.
     
  13. Blueknarr
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    Blueknarr Senior Member

    What advantage do you hope to gain with a fore-aft sliding dagger?

    Many years ago, I experimented with a dagger that pivoted a few degrees at the exit slot. As DCockey stated. Adjustment under load was impossible.

    On most boats small enough to use daggers on, shifting crew weight adequately moves the point of lateral resistance.
     
  14. upchurchmr
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    upchurchmr Senior Member

    Raking it forward or aft moves the center longitudinally and adjusts the balance.
    How much do you want to move the cp?
     

  15. heycaptaingg
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    heycaptaingg New Member

    +/- 500mm
     
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