Best hull design for Kiteboat?

Discussion in 'Boat Design' started by Hacklebellyfin, Oct 5, 2008.

  1. Hacklebellyfin
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    Hacklebellyfin Junior Member

    What would be the best hull/boat design for a kiteboat providing:

    -Offshore capabilities
    -Living space for 4 persons
    -Free space on the deck to allow non-navigating activities

    -Simplicity of construction

    Thank you
     
  2. masalai
    Joined: Oct 2007
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    masalai masalai

    Kites need to be SAILED - that is moved in a gradual figure 8 pattern to develop power (go look carefully at the kiteboarders playing in the small surf/waves) then this site has a few links showing kite sailing using a beach cat. It required 3 fit guys working in rotation as it was hard work, but thrilling fun... One to steer, one to manage the kite, and one ready/resting....

    This technology works (sort of) on larger vessels 100 plus ft long with plenty of aux power to drive the control systems actively....
     
  3. eponodyne
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    eponodyne Senior Member

    Masalai, I'm convinced that kites can be used to good effect on small craft. It's just that the technology is still very much in its infancy; I doubt there are two dozen boats worldwide relying on kite power. The beach cat video looks a lot like some rum had been involved.

    Some kites need to be flown all the time. Some don't. The kiteboarders move the kite around to help develop lift for jumping. But sheet in and "park the kite" and fairly quickly forces reach an equilibrium, the kite stays where it is requiring only a bit of tending-- no more than a sail on a beach cat or spirited dinghy.

    Probably your best bet would be one of the Woods Design catamarans.
     
  4. masalai
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    masalai masalai

    Not quite, unless you are happily sailing mostly downwing-ish... to point a bit higher the kite must be worked to get the lift... still....
     
  5. BWD
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    BWD Senior Member

    To the original question:

    I think a bridgedeck cat with a short mast to launch and fly the kite would be the best.

    Definitely round canoe bodies, with easily adjusted daggers, to mitigate risk of tripping or overloading the structure when things go awry with the kite or the wave conditions.

    The mast should be unstayed but able to mount conventional storm sails of some type, as kiting in storms is hard on the kites and on the sailor's life expectancy.

    * * *

    Further ramblings of a kite afficionado:

    Surf kiters move the kites so much on a wave because they are nearly always turning, and have to move the kite so it will still be in front of them when they come out of their next turn. On the wave they only need a little pull so they use a relatively small kite. On the way out against the waves or upwind they sine-wave the kite to make more apparent wind/power since their kites are relatively small.

    The typical procedure to get upwind is to sine the kite a couple of times to build apparent wind and then park it between 30 and 45 degrees off the water, sheeting out a bit to let it run as far forward of the kiter as it can. Small amplitude sining can help maintain power in marginal winds but there is a downside, every time you steer the kite toward zenith it moves relatively abeam of you instead of forward. Hence the observation of not much upwind progress in spite of all the motion in the waves, while the kiters that race windward-leeward do so with bigger kites and don't move them so much on the upwind legs.

    How it applies to boats:

    To go upwind, you need a different type of kite -flatter, higher aspect ratio, slower steering response, more sheetability. With the mass of the boat you aready give up acceleration, so no need for a super fast turning kite. It's an opposite requirement to that of a kite surfer in waves.

    In kiting's marketing terms, you would benefit from a "foil," "bow," or "ultraflat" shaped kite. Whereas for wave kiting, a lower AR, fast turning kite usually falls into the category called a "C" kite, "hybrid" or "SLE."

    Of course if you want to just go downwind, a deeper profile kite with plenty of drag is fine, more like a spinnaker.

    Upwind performance still has a long way to go, but it's coming along.
     
  6. eponodyne
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    eponodyne Senior Member

    Darnit, HackleBelly, where are you? Don't just ask a couple questions then leave!! How will the ideas be explored without the cut and thrust of informed debate?
     
  7. masalai
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    masalai masalai

    eponodyne, did you mean informed or uninformed debate? - careful it can be interpreted several ways - depending on certain assumptions :D
     

  8. ancient kayaker
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    ancient kayaker aka Terry Haines

    He's in "Siam" - last seen building a steel canoe.
     
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