rudder design / shape for high speed Kite-sailer

Discussion in 'Multihulls' started by 4wings, Jan 23, 2012.

  1. 4wings
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    4wings Junior Member

    Just wonder if any one has a basic suggestion about the best rudder design for a 30' multihull like "kite-sailer"
    Hull ratio is 1:10 - and even if it will look like a trimaran it is not intended to be sailed like one - more like a Hawaiian sailing canoe http://oceanpaddler.tv/index.php?option=com_seyret&Itemid=53&task=videodirectlink&id=97 where the Amas just tip in if a gust exceeds the expected force.
    I would like to hold the blades short to avoid damage during involuntary grounding ... was even considering to have 3 small rudder blades compared to a single one as in powerboats.
    From past experience the rudder blade works only well under certain conditions - as speed is changing so do the forces on the helm .. what is great at high speed is sometimes insufficient at low speeds - or is wearing the helms men out at high speed ...
    Any suggestions to how to overcome this design aspect?
    Thanks
    Michael
    http://www.kite-sailer.com
     
  2. Doug Lord
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    Doug Lord Flight Ready

    Here's a picture of the rudder on Hydroptere-the fastest sailboat on the planet-might help. Doubt you need the T-foil-except maybe to pull down(along with a small main foil to pull down)?

    The red line is forward...

    click on image:
     

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  3. spidennis
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    spidennis Chief Sawdust Sweeper

  4. Doug Lord
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    Doug Lord Flight Ready

  5. spidennis
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    spidennis Chief Sawdust Sweeper

  6. Doug Lord
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    Doug Lord Flight Ready

    ================
    This boat appears to be able to do that and I think Peter Lynn(NZ?) has singlehanders.
    http://www.youtube.com/watch?v=ruBQ1CM_VUA
     
  7. spidennis
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    spidennis Chief Sawdust Sweeper

    that's interesting!
     
  8. 4wings
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    4wings Junior Member

    Foiler in step 2 only

    Thanks for the reply and the image of the rudder - just for getting the prototype off the ground want to avoid the use of foils ... just one more can of worms which might spoil the project -
    Initial approach is to make it as much KISS ( Keep It Simple Stupid ) as possible.
    Saw in the videos the line setup for the kite is stable and did not allow a lot of change ...
    @SPIDENNIS - initial trials will be in the bay - once I find a way to lower and raise the kite safely ( so it can pass through the bridge and under the old power lines ) want to test it in the Brownsville shipping channel as wind and wave pattern is perfect ... but that is after a lot of work ...lol
    I do not think it is safe to bring all down to "single hand" it - thought the first approach is to make it family friendly and allow to take some friends with you.
    But guess no one has a thought on a small but multiple blade set up .
    Thanks for the input
    Michael
     
  9. spidennis
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    spidennis Chief Sawdust Sweeper

    Yeah, you'd certainly want to reel in the kite some when going under the bridge and those power lines near the old causeway! The Parasailers operate between the two all the time, but I never see a kiteboarder there ....... you'd be the first!

    there are more complicated systems for the reel and spool of the kite. One gal sailed across the pacific with hers though I never saw the kite being deployed or stowed. There are some pics of the reel though but I didn't see how she steered the kite or the boat. It seemed simple enough in construction. I'll see if I can dig that up.

    When you do your tests or need help contact me, I live on the island and I'd love to help. I got my back yard on a corner lot so it's turned out to be my boatyard with easy access, we could do some work on your boat there if need be. Yup, a 30' boat will fit back there! I also have an empty lot that we could use, I maintain it for the owner so I got access as I need it.

    edit: here's that gal link
     
  10. 4wings
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    4wings Junior Member

    @spidennis the patch between bridge and old power lines is not very appealing as 80% shallow - I did not consider a total retracting system more to run lines in S form between the crossbeams over open pulleys to lower the kite in a safe position. 2 lines on each side.
    On this web page : https://sites.google.com/site/iwkitebeatsall/ they mention to fill the bladders with helium to make the kite lighter than air and kind of self-raising ... cute but at a later point to play with.
    Thanks for the link - but believe her hull shape is a bit to wide to accelerate ...
    DougLord posted a link to the http://project.kiteboat.com/video and their setup is close to what I had in mind - just I want to have the main hull wave piercing and going through the wave and the Amas would be seaplane floats in stitch and glue - have to admit the link proved that we are on the right track ... as such thanks for posting it ...
    I can launch right from behind my shop - just across the bay from you in Laguna Heights - if we get a bad hurricane this year might launch out of the shop ...lol but thanks for the offer.
    I'm kind of appealed by the small surf board fins - and thought could set up rudder 3' forward of the transom and use three small rudder blades of rough 12" x 4" to hold load low.
     
  11. spidennis
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    spidennis Chief Sawdust Sweeper

    This is Hurricane Alex and an AP photographer (along with the rest of the media) was waiting around for something to happen when I finally showed up.

    I went down into my garage and my kayak was floating there like it was in a boathouse. I paddled out from my yard to the main drag and paddled to the mall and then up to TED's (and back a couple of times).

    I had to leash my prindle to the palmtree before I left as it was floating away ....


    [​IMG]
     
  12. spidennis
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    spidennis Chief Sawdust Sweeper

    the waterbikes over at Laguna Bob's use a front mounted fin steering system which seems pretty effective, but at sailing speeds? It certainly would be easy enough to find a bunch of windsurfing fins around here huh? I know I got a few! Would that be enough bite for a craft as large as yours? and I gather it would feel a bit like front wheel steering like on a car? the back end would just follow along what ever the front was doing?
     
  13. 4wings
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    4wings Junior Member

    @spidennis - you misunderstood me - the setup as in surfboards - 3 blades in triangle form aft appeals ... not the blade material - I assume it will break once you gain speed.
    Thanks Michael
     
  14. 4wings
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    4wings Junior Member

    After some more searching found the following craft / vessel :
    http://yachtpals.com/sailrocket-sail-rocket-4021
    Which claims to be the fastest sailing vessel on the water with his 52knots ...but that is not what I'm after anyway ... at closer look you see he has a dual rudder setup http://yachtpals.com/files/news/sail-rocket.jpg which is for conventional sailers quite small ... since it did not break during his speed's I guess we can assume it works.
    As the principle is proofed - will give it a try
    Michael
     

  15. spidennis
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    spidennis Chief Sawdust Sweeper

    Looking forward to seeing you out on the water sometime!
    Texas200 maybe?
     
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