Stand-up Paddleboard Design

Discussion in 'Boat Design' started by Doug Lord, Nov 7, 2011.

  1. EvanStufflebeam
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    EvanStufflebeam Junior Member

    I'm planning on building a catamaran SUP in the coming weeks, and am working on a few different design ideas. I'm in Phoenix, AZ, so all I am looking for is a good cruising board for some of my local lakes. I'm looking anywhere from 10-12 ft long, and figuring out what width would be best for the board. I'm planning on a foam core covered with fiberglass.
     
  2. CatManDeaux
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    CatManDeaux Junior Member

    You ever work on it? I'm planning the same thing but wanting to build something fast enough to compete in some of the local SUP races. There's next to nothing online concerning building catamaran SUPs. My next project will be one rigged out for fishing.
     
  3. upchurchmr
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    upchurchmr Senior Member

    I built a catamaran row boat which might be comparable.
    11' long by 5' wide with 6" max width hulls, basically shaped as a section of a circle from front to back on the waterline. that section was rotated to shape the bottom of each hull.
    That size will get you ~175# load total - boat and "rider" (whats the proper term?).

    There is no question that 5' overall is not necessary, but at that width there is absolutely no wave intererence between hulls. You probably could not stand the 5' either.
    One concern I would have is the height of the standing platform off the water. On a calm lake I would guess you need at least 4" which seems like you will need a longer paddle. As shown in the picture the freeboard on the hulls is ~4" for reference.

    In the picture below the crossarms would have to be moved to be centered for your standing platform.
    Just one note, my initial try had the bow and stern ending right at the waterline. Great for turns but we could not keep it going straight. Dropping the bow and stern into the water about 1 1/2" made it easy to keep on a straight line, but at the cost of easy turning. Somewhere there is a good balance depending on what you want to do.

    Just FYI, I'm not planning a SUPcat any time soon.

    [​IMG]
     
  4. Skyak
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    Skyak Senior Member

    The fastest stand up paddling I have done is on a sit-in kayak. SUP is very low powered and wide boards waste power by paddling off center and changing hands often to stay on course. A good 12 to 16ft kayak with the seat removed and a board to stand on (without it the hull deformation takes away from stability and balance) is more efficient than 90% of SUPs at least. Kayaks are narrower than most SUP but there is not much difference in stability -it's just not that hard. I have never fallen but I have a long history with skateboards, biking and skiing so I skipped the beginner SUP plunges. I think much of the popularity of SUP is that it is not as hard as it looks. Paddling a 24" wide SUP is no problem for anyone with experience.

    The only exception is wave powered surfing -where you obviously want a surfboard -plenty of flat width and rocker, no sharp edges. In my mind bringing a paddle on your surf board is not SUP.
     
  5. CatManDeaux
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    CatManDeaux Junior Member

    Well, I'm not trying to design a fast boat or kayak. I'm trying to design a fast SUP with the best balance I can get between speed, weight and stability using sustainable recycled material. I know most SUPs are inefficient. This is just my own little project. I gotta build something. :)
     
  6. Skyak
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    Skyak Senior Member

    "Sustainable" to me means don't make landfill garbage. "Recycled" does not mean post-consumer and does not make garbage production forgivable.

    There are plenty of marine ply SUP designs that are better than what you will come up with in 5 trys. They will last a lifetime. The question is which one is right for you? Get out and try some existing designs. If you are a beginner, don't build until your capability develops -you will not be happy with a sluggish beginner board for long. You completely miss the point -when skill reaches full capability the best SUP hull IS a good kayak hull of a length correct for the reduced thrust.

    I see you are considering a Cat. You could build a pair of hulls the right size and experiment with spacing. Upchurch's design looks like a good starting point. There is no more sustainable material than scrap wood.
     
  7. CatManDeaux
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    CatManDeaux Junior Member

    I have found every single catamaran SUP design that has been posted to the web, I promise you. There are more out there than you think. These are two of the fastest ones ever put in the water. The longer of the two is carbon fiber and held it's own with two of the fastest boards on the planet over 14 feet.

    Two similar boards:
    [​IMG]

    This one is a custom build that is in it's 3rd generation (the fast one). It's the SIC S-16.
    [​IMG]

    Lastly, I've seen video of this thing (in spite of it's size and weight) performing way better than your average 12 foot board both in the surf and in the ocean. Its built for fishing but it's faster than anything else in it's class considering the amount of deck space. It's the "L2Fish" by LIVE Watersports in Florida.
    [​IMG]

    It doesn't take much to outperform most 12 foot recreational SUPs because of the surface area. And being told I can't do something on the 5th try is all the more motivation to do it on the 1st. ;) Lastly, catamaran SUP designs eliminate the instability issues of single hull designs.

    Besides, isn't this a forum where people hang out who BUILD boats? Why would I be here if I wanted to BUY something instead of build it? Where's the fun in THAT?
     
    Last edited: Jun 2, 2014
  8. CatManDeaux
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    CatManDeaux Junior Member

    This one is cool too. Interesting design. Sits higher in the water than I would like.

    [​IMG]
     
  9. Skyak
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    Skyak Senior Member

    This is the design forum. The build forum is here; http://www.boatdesign.net/forums/boat-building/

    This is not so much a "hang out" as a place for the exchange of fact. We all love to see actual results of builds. On the other hand suggesting you will make something superior in your first try without considering the state of the art is more than a little annoying and makes me wonder why you are here if not to learn or teach.

    Did anyone suggest you buy your SUP?
     
  10. CatManDeaux
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    CatManDeaux Junior Member

    I'm not suggesting I'll build something out of the blocks that's better than everything else, but I do believe I can build a 12-13 foot board that is more stable and faster than most 12-6 boards with a single hull using a derivative of existing designs I have seen.

    As for "considering the state of the art," I'm not sure I completely understand your assumption but know that I'm not ignoring the science, nor am I ignoring other designs. I'm just looking to do something no one (that I have seen) has done before and have fun doing it. With the relative speed of similar designs, I can't see how the board I build can possibly be "sluggish." I just sold a Jackson SUPerFISHal. You wanna talk sluggish? Worst SUP ever made. Doesn't track straight (remotely) and I can dog paddle faster than that thing went and paddle faster on a piece of flat foam.

    As for the buying question, I misread your reply. Sorry about that.

    As for being a "beginner" boat builder, yes, I am, but it doesn't mean I'm incapable. I don't do things half way and I'm a research fiend. I will determine, by trial and error, by scientific means, and by asking others what is the best way to accomplish what I'm planning before I do it. And yes, as much as my confidence is "more than annoying," that doesn't make it any less plausible. The first house I built was better than the work many "contractors" do. Did it take me longer? Yes. Did I make mistakes? Sure. But it was worth doing.

    Lastly, there's no reason I can't learn from others who have used other materials. Many of the concepts translate and aren't completely foreign. My point is, to me, the fact that everyone else does something differently, and the same way, is all the more motivation to try something new.

    I'm not trying to start an argument. I'm just going to do something new. It's what I do. In the words of Picasso, "I am always doing that which I can not do in order that I may learn how to do it."

    I'll post more when I start playing with my design in Illustrator and get some feedback and suggestions.
     
  11. Michael Y
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    Michael Y Junior Member

    How tall are you? Me standing in my hard-chined kayak with nice form stability would still be like a one-legged man in a bass fishing contest. So to speak.

    I rented a touring SUP at the beach, and regretted its lack of beam.
     
  12. Skyak
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    Skyak Senior Member

    I am 6' 2"

    Maybe I am off on my beam estimate. I stand in my 16ft loon all the time. It is 30" max beam ~26" waterline beam. It is as stable as any beginner SUP I have been on but might hurt more to fall. To me it's walk around stable.

    Standing without a paddle is another story. I don't stand fishing because I expect big ones -Nantucket sleigh rides.
     
  13. Skyak
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    Skyak Senior Member

    I am all for experimentation, but many experiments have already been done and results might be predictable. I am glad to hear you already have SUP experience and an idea of what you want.

    That "quick blade" design is interesting. I wonder if the parallel plane inside hull edges avoid hull interference drag -does anyone know? I am thinking waves don't add drag to perpendicular flat faces. It would be nice if such a design was low drag because you could expand it at your destination for stability and retract it to move. I wonder if it edge steers if one hull is deeper than the other.
     
  14. CatManDeaux
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    CatManDeaux Junior Member

    LOL! I'm 6-1 and I've fished standing up from canoes. I'm good with balance and I'm even working to improve it by doing a slant and wobble board regimen from a guy up North named Eric Orton. (Probably won't know him unless you run. I digress.)

    And that quick blade design is close to what I'm planning, except with a deck where I can paddle it either direction. Imagine similarly-shaped hulls with a deck on top shaped at both ends like the node of a surf board. As for waves, well, I'm building a flat water board.

    As far as "expanding at my destination," well that is complete Greek. English man, English. :D
     

  15. Skyak
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    Skyak Senior Member

    The waves I was talking about are the ones you produce by moving so it applies to flat water SUP. SUP boards tend to have skegs for tracking so I would not plan to paddle in either direction -just one.

    By expanding at the destination I just mean that the overall beam could be adjustable -wide when you are stationary fishing, narrower when you are moving. It could be wider when you are a beginner, narrower when you have more experience. Just consider it adjustable stability.

    Your design sounds pretty good. I suspect similar ones will follow.
     
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