Skin-on-frame canoe/kayak plan help

Discussion in 'Boat Design' started by Ruming Jiang, Mar 8, 2021.

  1. mitchgrunes
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    mitchgrunes Junior Member

    This boat isn't exactly what you want, as it is more kayak-like than canoe-like, fits only one person (but as I said, if you have 2 people, it is a lot safer to put them in seperate boats, to help with rescue), and it is 28 pounds, not 20.

    Foldable Kayak | Tucktec Folding Kayaks https://tucktec.com

    1. It is a pre-made boat , not DIY ($350, shipping included). But some of the ideas might be interesting for a DIY.

    2. I'm not certain, but it might meet your single-direction bend criteria.

    3. It folds to 48" x 15" - roughly trunk size, though I don't know the size of the trunk in the cars you name.

    4. Very fast assembly. The site video shows a gal assembling it in 90 seconds on her 4th attempt - so they say. Looks easy in the video.

    5. The hull-top foam sponsons won't interfere with speed unless you tip over pretty far - and then they stabilize the boat. Would also be a smooth place to rest your arms. Very cool idea.

    6. It is only 10' long - but that is almost all waterline, which is what matters.

    7. I think it was just made from a flat plastic sheet, with a little extra hardware. You would need a fairly large piece, especially if you want it to be more canoe-like, and a little longer for speed.

    8. If that is too heavy to carry all the way to the water, especially if it is made less flimsy and a longer, for two, the way it folds could easily fit on an ordinary luggage cart, especially if you tie it down with a bungie or rope You don't need a boat cart.

    9. This review of the pre-made boat



    said it took 3-4 months to arrive, some of the components are flimsy. It comes with no flotation - I think you need airbags at the ends for safety, unless you only paddle it next to shore. It creates bigger bow and stern waves than a performance boat would, and has a wide flat bottom, which means you waste power on moving water and friction. But I bet your design does the same.

    10. If you did somehow flip it, I doubt you could re-enter it from the water, but I doubt that for your design too.

    11. This video



    clarifies assembly and shape. It has a fin to keep it straight, which must slow it down even more, and is pointless in a boat this size amd shape, especially if paddled with a kayak paddle. Also, looking at the way it folds, the creases would catch the water and slow it down more. I wonder if that is part of of the reason for the relatively high bow and stern waves.

    12. I assume you want a canoe rather than kayak to carry a lot of gear - like a big heavy cooler. You'd want something a lot sturdier for that.

    So just look at the design for ideas, like those hull-top sponsons.

    On another topic - The way I see it, Coroplast and similar materials has one big problem: Once you have made it, you can't redesign the shape, if it doesn't do what you want. In contrast, you can build a SOF boat out of thin flexible PVC pipe, taped together (including stringers and cross pieces for rigidity), and create the skin for initial prototypes out of packing tape or similar, or duct tape, or shrink wrap tape, leaving the ends of the pipe uncovered, sticking out. Then, after trying the boat out, you can remove the cheap tape, to play with the design until it feels right in the water, and build the final result using slightly more sturdy connections and use a more durable nylon or polyester skin, which you coat for waterproofing after you have the shape right. Eventually one might substitute bent plywood stringers for the PVC pipe, to save weight. That is pretty close to what other people suggested I do for experimental purposes for a kayak in another thread, though the thin PVC pipe + duct tape prototype is my idea, for something ridiculously easy to build and modify. But I haven't tried it yet - still collecting ideas. E.g., for a take apart design, I want to connect together two shorter pieces of PVC pipe, but need a more permanent but still take-apart way to connect them in a final version.
     
    Last edited: Mar 17, 2021
  2. Ruming Jiang
    Joined: Mar 2021
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    Ruming Jiang Junior Member

    Thank you Mitch. It just tells how hard people have tried to make it portable. But as you can see from the video, it's neither light (for its size) nor durable (breaks after first paddle). It is just another proof that folding may not work optimally.

    I agree that two smaller ones are safer than a larger one from rescue perspective. That will be something down the road when I plan for expedition version. For weekend with family, I'm not sure yet. Wife enjoyed our first paddle by doing nothing except selfie.
     
  3. upchurchmr
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    upchurchmr Senior Member

    Developable hulls are a design compromise due to material manufacturing cost and design capability constraints.
    The goal should be 3D fully contoured shapes which can give better performance.

    Tucktec looks like everything bad that has been commented on in this thread.
    How could anyone want to put his life in such a thing?
     
  4. Dave Gentry
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    Dave Gentry Junior Member

  5. upchurchmr
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    upchurchmr Senior Member

    Dave is a real expert, rather than us with just opinions.
    The best help you have seen yet.
     
  6. Ruming Jiang
    Joined: Mar 2021
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    Ruming Jiang Junior Member

    That's been on my reference list but thank you.
     
  7. mitchgrunes
    Joined: Jul 2020
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    mitchgrunes Junior Member

    I'm the one with opinions rather than construction expertise. :) I have paddled a fair number of boats over many decades, have seen the problems I and others have with them, and know what I and friends like, but I haven't built one yet. And my bias is towards controlability rather than passive stability.

    Perhaps paddling with family is when safety is most important. You could paddle with groups, and practice rescues in safe places with them. There are many stories of people who paddled solo or on the same boat, because they thought their boat was stable, but it tipped for one reason or another (say, a power boat wake, or unexpected weather), then died or needed rescue, because they couldn't get back in, far from shore. (Other sometime factors: not dressing warm enough for immersion, or not wearing life jackets, which are hard to put on once you are in the water, or letting go of your paddle or boat blow when you tip, which blow away in the wind - hence paddle leashes, etc.)

    Yes! Though it is light for its length and width. In fairness, the guy did not follow the correct assembly steps. He briefly looked at the video on-line, then tried to figure the rest out himself, with mistakes.

    All the folding and take-apart boats (admittedly sea kayaks, not canoes) whose owners I have paddled with and asked about this, have required occasional repairs, and most folders have required some strength to assemble. Most of the owners think it worth it. Some of them (such as some of the Folbots and Nautiraid brand boats, and possibly one of the Oru models) have been pretty good boats. One well known professional sea kayak instructor I took lessons from, has no car, but regularly carries his on trains and buses.

    I wonder how durable a material bamboo is. Perhaps this is fairly light:



    There are lots of videos on making bamboo kayaks and other boats on Youtube. And, as others have pointed out, lots of websites and plans on making all kinds of boats. And kits to make it easier, as well as full size plans that you might tape or glue onto the wood before cutting it. I think most people who design and build their own do so because they enjoy that at least as much as using them.

    I am curious: Why choose a canoe (that you sit in with your legs below your knees, or kneel in), rather than a kayak (that you sit in or on, on the bottom, with your legs ahead of you)? There is a lot of variety, but OVER-GENERALIZING A LOT: Kayaks are less tall, so are lighter, easier to tip back upright, and maybe less prone to being tossed around by wind and waves. Most sit-on-tops are self-bailing. A few of the "surf skis" are simple - a surfboard (perhaps you could start with a cheap foam surfboard or two spliced together for flotation, and add wood on top), some with indented and/or high friction and/or padded seats and foot rests. Surf skis are easy to get onto from the water - scoot in from the ends, with the boat between your legs, or in shallow water just step over them and sit down. Most places I go canoes have fallen out of favor.
     
    Last edited: Mar 19, 2021
  8. Ruming Jiang
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    Ruming Jiang Junior Member

    Don't have strong opinion among canoe and kayak. I've been actually pondering the difference between them. Canoes just happen to have plenty of space for me to be with families but I'm sure Kayak will be something down the road.

    Bamboo, like all other natural materials, is good only when available at low cost, or in special occasions like survival, otherwise the material industry has made enough progress to replace it.
     
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  9. mitchgrunes
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    mitchgrunes Junior Member

    There is so much variety that canoes and kayaks and surf skis kind of blend together. You could make a big multi-person kayak or surf ski or scull too - though weight goes up with size in any boat. Some boats now can be adapted to sitting, kneeling, or standing; paddled, poled, rowed, sailed, pedaled, powered and/or used as diving platforms. (But multi-use devices are seldom optimal.) I don't know what to call them.

    I personally wouldn't put a very young child in a kayak - though they aren't completely safe even in the more stable canoes either. But I've known families who started pretty young.

    Two bladed paddles used to be used only in kayaks, but people use them in open canoes too, because they are more efficient and make steering easier. "Drip rings" help prevent water in the boat, from water that drips off of them - but aren't completely effective, so you may have to bail a bit.

    Kayaks are usually closer to the water (except for decked canoes, which are only different from sit-inside kayaks in that you kneel rather than sit), so you get more wet. But you should dress for possible immersion in any small boat, sibling interactions can tip small boats even in flatwater, and kids have splash fights, even within the same boat.

    Since kayaks are less tall, they fit on top of cars in parking garages better. Some people bring bikes, skis, boats, hiking and camping equipment on the same extended trip. You may not have room for a boat inside a car.

    I'm NOT the right person to say how canoes are better, but I will try: Traditionalists say canoes and single bladed paddles require more skill and endurance, so "Twice the paddle, half the man". Canoes are typically better for fishing (though some specialized kayaks have adapted). Big heavy boats force families to work together, to load and unload boats (so cartops are better), and carry them to the water, which might be a good thing. Carrying heavy boats can be part of an athletic conditioning program, and can be an interesting challenge over rough terrain. More canoes than kayaks have outboard motors mounts. Kayaks are too popular now; canoes make you unique and special. At the top end, I think kayaks are more expensive.
     
    Last edited: Mar 19, 2021
  10. ImaginaryNumber
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    ImaginaryNumber Imaginary Member

    Kayaks can be family-friendly too. :)

    [​IMG]

    [​IMG]

    If you are not use to it, sitting in a confining kayak with your legs straight out in front of you can become rather uncomfortable. In a canoe it is much easier to vary your seating position -- sitting or kneeling; paddling on left side or right side; paddling from bow or stern.

    A single canoe that can hold two (or more) people, often weighs less than two single-person kayaks. And in a two-person canoe (or a two-person kayak) a strong paddler can help a weaker paddler. However, single-person boats give each paddler the freedom to chart their own course and visit whatever they want.
    [​IMG]

    That would be too dangerous! Get them their own kayak -- with training wheels, of course. ;)

    [​IMG]
    When paddling a kayak you basically repeat the same stroke all day long. No variation in the muscles you use. In a canoe each arm uses different muscles, so by switching which side you paddle on you can rest each set of muscles. And canoe paddles don't drip on you. When paddling in winds the lower-held canoe paddle can be desirable as it doesn't get caught by the wind so readily. Of course, the canoe itself is more affected by wind than are most kayaks.

    [​IMG]
    Just put all that stuff ON the kayak!

    [​IMG]
    [​IMG]
     
  11. Kayakmarathon
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    Kayakmarathon Junior Member

    Canoes are propelled by single bladed paddles. Kayaks are propelled by double bladed paddles. This is how the International Canoe Federation (ICF) differentiates a canoe from a kayak. Under ICF boat class rules, a "canoe" can enter a kayak race as long as it is propelled by a double bladed paddle; however, a "kayak" cannot enter a canoe race even if propelled by a single bladed paddle. Rudders and extensive decking are permitted on "kayaks" but not "canoes". "Canoes" have a limited amount of decking and number of thwarts.
     
  12. portacruise
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    portacruise Senior Member

  13. mitchgrunes
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    mitchgrunes Junior Member

    ImaginaryNumber, I love the pictures you came up with!

    A book I read, - maybe Zimmerly's - mentioned that some arctic kayaks were designed to hold a family under the decks!

    Lots of people race 2 person kayaks. But the o.p. doesn't seem to be looking for a super-fast unstable boat.

    A lot of commercial sea kayaks have room to vary your position somewhat, though many people outfit their boat so that isn't true. I would prefer a kayak that let met put my knees up, because I am more efficient that way, and it gives me the flexibility to bend forwards and sideways more. It is one of the main reasons I want to design my own boat.

    Wow! I've never seen a kayak as small the one in your picture. So cute!

    For beginners, and those who never learn other stroke styles. Realistically, a lot of people like two bladed paddles because they seem very intuitive, and they don't learn any more than they have to.

    If you know enough to find those pictures, I'm sure you know there are many different stroke variations to reduce fatigue on long trips. Vertical paddle vs semi-sweep vs sweep vs extended paddles (especially with Greenland paddles, which are very cheap to make). Half length vs full length strokes. One hand vs two hand vs zero hand control (in which you let the blade rotate within your hands). Torso rotation and bend vs shoulder and elbow use. Bent elbows vs straight elbows. Support vs non-support strokes. Varied in-water trajectories. Occasional practice at turns and sculls, compound strokes, quick rolls. Paddling backwards. People usually switch sides on every stroke, but I sometimes use a two bladed paddle almost like a one bladed paddle. Some sea kayakers I have known switch off with a one bladed paddle.

    I haven't managed to fix another problem. My hands get sore, almost arthritic, from being curled around a paddle shaft too long. Are there reasonable ways to use a one bladed paddle that fix that?

    Anyway, the o.p. has a much more difficult problem: The wife wasn't interested in actually paddling. He may be willing to do all the paddling, but kids probably wouldn't go for that. I wouldn't be surprised if she eventually stops going altogether.
     
    Last edited: Mar 20, 2021
  14. ImaginaryNumber
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    ImaginaryNumber Imaginary Member

    Did you notice the "training wheels?" The man is sort of holding on to one.

    [​IMG]
     

  15. Tiny Turnip
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    Tiny Turnip Senior Member

     
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