hi speed kayak need input

Discussion in 'Boat Design' started by nwahs, Sep 13, 2011.

  1. nwahs
    Joined: Sep 2011
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    nwahs Junior Member

    i started wanting to scull some at a small lake by the house here in IA
    well not a lot of boats here, most are on the east or west coast.

    then i noticed, there was not a big difference between olympic single scull and kayaks at the 1000m.

    now, later i would still like to scull- but im leaning for simplicty at this moment sake for the fun of it to make a hi speed kayak- (all my preavious exp has been white water kayak)

    im thinking around 24' (size of the basement room to store this thing),
    beam@ 13" , im looking towards like a surf ski, but i dont need the deck volume or strenth for open waters. so its more the profile of a scull, with out the sliding seat, riggers ect, but propelled like a kayak.

    im curious as if if any one out there has seen or built any thing like this.

    i would like imput
     
  2. Squidly-Diddly
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    Squidly-Diddly Senior Member

    one big reason for very long sliding-seat boats is to

    mitigate the weight shift hobby-horsing, which isn't a factor with kayaks.

    I had one of these.....

    www.paddlerzone.co.nz/products/kayaks/surf_skis/ocean_kayak_sprinter

    and the rudder was absolutely required to deal with weather cocking, but it did have quite a bit of free board, even with my 275lbs. These boats were made for ocean use, so your low freeboard might be a little better, but not much if near 24'.

    I did notice it didn't seem to put out much of a wake or bow wave even when paddling as fast as possible. I'm not sure you will see much more speed with a longer, narrower boat.

    Thought about a hydro-foil kayak?


    biggest diff between fast scull and fast kayak is in the scull you can cruise for hours, where as in the kayak it will be truly 'sprinting'.
     
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  3. nwahs
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    nwahs Junior Member

    yes i wantted to keep free board to a minimum, but i guess i need some vertical (web/ beam effect) to stay stiff, i think static ill have about 3.5 draft, so 3 to 4 free board im hopeing 7 tall will keep ridged.

    yes i would think, "hobie Horseing" as you put it would wind up pumping alot of water,

    thx for the rudder imput, i was thinking of one just for turning, my perception kayak now is so short and squirrly its hard to imangine a rudder. thx shawn
     
  4. Hussong

    Hussong Previous Member

    24' is way too long for a solo paddler. Take a look at these K1 designs from Epic Kayaks. The principal design input is from Greg Barton, two-time Olympic Gold medalist, so there is a strong foundation for the length and beam applications which work best.
    http://www.epickayaks.com/products/icfracingkayaks

    There is a length limit beyond which it makes no sense to exceed. True that long skinny hulls can achieve faster speeds, but there is also a huge wetted surface penalty for extremely long boats. Unless you are Godzilla strong, really fit, and have extraordinary paddle stroke technique, all you will be doing is getting wiped out trying to push all that boat through the water with no great speeds.

    I wouldn't go over 19' for any solo craft and no skinnier than you can keep upright.

    The optimized length for an average paddler in a well designed sea kayak actually hovers around 15' 6" with a 23" beam. If you are looking to go longer to get more speed, it will have to be coupled with very narrow beam numbers. Still, 19' is the practical limit.

    Just some ideas.
     
  5. messabout
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    messabout Senior Member

    Hussong has givenyou the straight dope. Unless you are superhuman, too much length will be a hydrodynamic disadvantage. Nineteen feet by nineteen inch beam is approaching the practical limit.

    There are several threads on the forum that deal with this subject at great length. Some plenty smart people are contributors. Browse the forum to find those threads and get the good council from a lot of people who have "been there and done that". Rick Willoughby and Leo Laszuskas (both Aussies) are among the most erudite contributors. There are numerous other screen names that need to be given respect for their knowledge of such stuff. You have come to the right place.
     
  6. nwahs
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    nwahs Junior Member

    thx for the going beyond the point of deminishing returns heads up. 19'& 19" beam
     
  7. nwahs
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    nwahs Junior Member

    skin drag vs form drag for human power craft chart

    dose any one have a chart for skin drag vs form drag for human powered craft???
     
  8. Gary Baigent
    Joined: Jul 2005
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    Gary Baigent Senior Member

    If you want maximum speed, go 19-20 feet length with beam ... a fraction wider than your hips. There are some kiwi designs here at 16 inches beam (but they're definitely tippy).
     
  9. Manfred.pech
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    Manfred.pech Senior Member

  10. nwahs
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    nwahs Junior Member

    thx my currant white water boat hip support foam is carved out at 15-1/2", i cant see quite see gittin an exterior dem of 16 (with out elevating my position- id perfer not) but i think 16.5 is do able.... old age and child bearing hips suck.
     
  11. nwahs
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    nwahs Junior Member

    thx for the pic/ link
     
  12. JosephT
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    JosephT Senior Member

    I paddle K1 olympic kayaks & competition surfskis with a narrow 16.5" to 17" beam. If you want to get into this sport I would suggest the following:

    1. Forget whitewater paddling technique...doesn't apply.

    2. Get a kayak ergometer and learn the Olympic K1 stroke. Kayakpro, Vasa, PaddleOne & a few other companies make them. If you don't learn the stroke on an ergometer it will take you weeks on the water to refine your technique & be competitive.

    3. When your technique is sufficient and your strength/endurance are up to par, buy a K1 sprint boat or surfski...plenty for sale new/used on the net.

    I prefer the Epic & Huki boats myself.

    Cheers,

    Joseph

    PS rowing sculls are a totally different training approach (not to mention paddling backwards). These hulls are not built to be paddled like a kayak. If you want to be a rower join a local rowing club & learn, use a Paddle One ergometer to improve strength & be competitive.
     
  13. nwahs
    Joined: Sep 2011
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    nwahs Junior Member

    thx josephT for the input, i will look into the ergometer,

    may i ask what type speed do you git from your surf ski, in calmwater/ windless conditions.
    you like them s1-x


    thx
     
  14. JosephT
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    JosephT Senior Member

    With a good carbon wing paddle on a calm day ~9mph is attainable in an open sprint, with 6+mph the average cruise speed (75% of max heart rate).

    If you do river races you can obvious tack on any free current speed to that. I have zipped down a river at almost 15mph once. It was at flood stage and a blast to go that fast. I'm more into marathon races vs. short sprint races so I focus more on optimizing my cruise speed. Obviously fueling/hydrating the body & a lot of training go into a successful race. This applies to both sprint & marathon races.

    Regards,

    Joe
     

  15. nwahs
    Joined: Sep 2011
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    nwahs Junior Member

    thx again for the info, 6mph cruisin sound real nice im working on a gps mount so i can start quantifing things out at the lake. i think i need to find a place a rent a few different to compair.

    im not looking to race as a sport- just looking for a fast cruiser- something with a good glide feel to it.......
     
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