low profile solo canoe. How low can I go?

Discussion in 'Boat Design' started by carpetman11, Mar 16, 2014.

  1. carpetman11
    Joined: Mar 2014
    Posts: 3
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    Location: upper Mississippi river davenport IA.

    carpetman11 New Member

    I have built several cedar strip canoes. I have forms for a sweet paddling 17 foot wilderness canoe.
    It is 32 inches wide.
    I have built it with 20 inch bow 12 inch center and 16 inch stern. 55 lbs
    16 inch bow 11 inch center and 14 inch stern. 48 lbs ( lighter gunwales )
    I am thinking about building this next one with a 12 inch bow, 9 inch center and 10 inch stern.
    Theoretical waterline is 4 inches. lightly loaded it is 2 1/2 inches
    2 people and gear for 7 days puts waterline at 4 inches.
    I have paddled my other canoes in the boundary waters for 4 great trips. been in real rough and windy water. my boat handled it like a champ. also paddled the Mississippi river with large boat wake never taken on any water.
    I am looking to build a lighter easier to paddle boat for protected waters
    any advice would be appreciated. I know this boat is a little long for a solo canoe, but forms are already setup true and ready to build on.
    I hope to build a 40 pound 17 foot canoe will use 4 oz cloth 1/2 inch gunwales
    let me know what you think? should I go lower11 inch bow 8 inch center 8 inch stern with a canvas spray skirt?
    anyone have experience with light weight canoes?
  2. rwatson
    Joined: Aug 2007
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    Location: Tasmania,Australia

    rwatson Senior Member

    A good fun project.

    The building method isnt clear here. This '4 oz cloth" - is that fibreglass or something like nylon ?

    Lightweight and Fibreglass dont always go together - especially if you are trying to do it with a single skin.

    I once built a 21 foot kayak, using5mm x 5 mm strips, covered in canvas. I did it for ease of carrying up and down the hill from my home, and the speed increase I got from 16ft to 21 ft was really noticeable for little extra weight. That made the trips even more enjoyable.

    My thoughts were "easier to paddle" means comfort, as well as weight, so don't make it too weird to get in and out of, at shore or a jetty for example.

    Sheltered waters may just be lakes and rivers, where a spray cover is more of a nuisance than a benefit.

    I am just finishing off two kayaks with 'snug' cockpits, and after testing, I was wishing that they had a more open cockpit on occasions. I am actually seriously thinking about cutting a large area out of the deck in such a way that I can re-insert the snug cockpit for heavy work, but remove it for the sunny, no fuss joyrides.

    You may like to consider that option.

    The other thing that you will have noticed, is that the wind is the real nuisance in kayak paddling, especially for light weight craft. I think their is a real case for removing high ends and square decks edges ( gunnels ) so that the wind has very little to 'grab'. The rounded edges on all above water structures makes a huge difference. Removing as much hull as feasible above the waterline, while leaving plenty of room for people, would be a great idea.

    It doesnt really matter if the waves slop over the bow and stern if they are covered.

    Ballistic Nylon, Skin on Frame is one of the most light weight ways of building a kayak with real puncture proofing.
  3. carpetman11
    Joined: Mar 2014
    Posts: 3
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    Location: upper Mississippi river davenport IA.

    carpetman11 New Member

    Thanks for the info. I have a 20 foot 19 inch wide kayak. it is crazy fast, equally as unstable. no fishing or bird watching. I would not even consider bringing a camera with me. but I have paddled 60 miles down stream with 2 portages in about 8 hours. not going to do that in a canoe.

    I am wanting to build a cedar strip low profile canoe. covered inside and out in 4 ounce s glass and epoxy. I have already built 2 canoes on this form. just wondering if anyone else out there has done a really low profile canoe. I taped toilet paper to the side of my other canoe at the 8 inch mark and it stayed dry except the bow. so I know i need a little height at bow. I paddled a real calm section with no boat wake, no chop. I like building boats, do not want to rebuild because of poor decisions. don't want to sink boat and loose gear, or scare my kids.
    just looking for guidance, and advice from someone who got it the hard way.
  4. Petros
    Joined: Oct 2007
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    Location: Arlington, WA-USA

    Petros Senior Member

    I do not think I would go that low without a canvas cover. Also consider that shaving the hull depth down weakens it since the depth is not there. The gunwale should be made much more beefy to compensate for the lack of depth, which means your weight savings will not be as great. I would try and save weight at the bow and stern since the bending loads are not nearly as large there.

    I have built a number of skin on frame kayaks in the 16 ft range (hull in the 6 to 10 inch total depth) that weigh only about 20-25 lbs. It is the lightest way to build, but the frame takes up some interior space if you need lots of cargo capacity. cedar frame with 9 oz nylon or polyester skin sealed with polyurethane floor finish yields a kayak under 20 lbs, the large and more junk you hang on it adds weight of course.

  5. rwatson
    Joined: Aug 2007
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    Location: Tasmania,Australia

    rwatson Senior Member

    I understand your aims a bit better, but I am still a little confused about your purpose.
    Petros' comment on frame space within SOF designs is an important consideration for ease of stowage and footroom.

    While the main reason for a low profile hull would be to reduce windage, the amount of weight it saves is fairly easy to calculate, and isnt that huge.
    A finished 16ft strip of 25 x 5 mm cedar + glass would weigh around 200 grams, so 4 on each side for a deck height increase of 50 mm would add under 1 kilo. That's about two sandwiches and two apples in a plastic containers worth.

    If you want to go really lightweight on a solid hull, the ultimate solution is a very lightweight core with glass on two sides.

    The most common way is to use hi-density foam, but its hard to control in thin strips. You may like to consider Paulownia timber ( association link )

    Its about 1/2 -2/3 the weight of cedar ( 380-400 pcm for cedar, 260-280 pcm for Paulownia) , equivalent strength, superior durability in water - and glues/epoxies extremely well.

    So say around 35 x 25mm strips for a kayak
    35 x .2 kilos = 7 kilos for cedar
    35 * .13 kilos = 5 kilos for lightweight Paulownia
    5 cm hi-density foam, about half of cedar = 3.5 kilos, but a heavier glass layer may be required.

    Using either of these two building methods would significantly lighten up your design without getting ridiculously small in volume.
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