Aug 01 2011

Of skin and wood

Published by at 2:30 pm under Expeditions and Experiences

I´ve been posting this on the Into the Woods blog a little while ago and thought some people who read this blog may also be interested in it…

It was spring – the maple sap was just beginning to flow and the white blanket of snow had disappeared from the ground. I had done some research about the styles of skin boats used by various Native peoples in the northern hemisphere and consulted a few people who knew a thing or two about that subject. I decided to construct a small canoe that would be ideal for exploring the small creeks and streams of this area, similar to the solo canoes made of fiberglass that my campmates and I use. Consequently, the dimensions are fairly similar, with a length of about 10 feet and the widest part being about two and a half feet wide (I can´t provide exact measurements since we don´t have any measuring devices at camp).

The frame was to consist of seven long saplings forming the sides and bottom of the canoe, with the keel/bottom pole connecting all the other poles at either end of the canoe. Hardwoods twist less when they´re drying than softwoods, and since I was looking for straight, flexible and preferrably light materials my choice of wood was limited to a few species…so let´s continue to

Part I: Assembly

On a fine cold spring morning, I ventured out by canoe to harvest the frame materials: I selected a dozen straight maple saplings for the main frame and about six dozen hazelnut shoots for the rib pieces. The first task was now to peel the bark off all the gathered materials for more rot resistance. Over the next days I slowly assembled the main frame, inserting wooden spreaders and support poles where necessary in order to give the canoe its intended shape. I ended up carving down and flattening most of the frame saplings and all of the rib pieces to achieve more evenly bend, and since the materials were green, no steaming or other treatment was necessary.

The first saplings are tied together
The main frame is in place, with some supports tied in to shape the canoe

Lashing the rib pieces to the frame required a fair amount of rawhide, since each of the 60+ ribs was tied to seven frame saplings, with the rawhide being streched as much as possible prior to tying it off to prevent loose lashings. In order to more securely lock the individual ribs in place, I wrapped rawhide along three of the frame saplings, connecting each rib to the neighboring ones. Still, the lashings allow for a little bit of movement and flexibility, which makes the canoe more shock-resistant. Say you´re bumping against a rock: The impact gets dispersed throughout the frame rather than being focused on the point of impact (which might cause a break) as is the case with e.g. nailed frames.

The first rib pieces are lashed in place

The raw frame was now finished, and I applied several coats of oil & a little bit of pitch in order to preserve the wood and make the rawhide lashings more water-resistant. Besides its preserving qualities, the pitch also helps to keep rodents and other animals from chewing on the frame to get at the fat…

The finished frame

Now came the skin cover. Ideally one large hide would suffice to cover the frame – no sewing required, and besides that, every seam is a potential weak spot too. With no such hides being available to me at that point, I pieced several smaller hides together – one small buffalo hide and four deer hides proved to be sufficient.

Skins draped over loosely before sewing them together

In my research about skin boats I came across a waterproof stich that several Inuit tribes used for their kayaks and umiaks. It´s a rather time-consuming affair since the stiches do not go through the entire hide, but instead enter and exit from the same side.

Detail view of waterproof stich consisting of two parallel seams

Once the cover was finished, I folded it over the sides of the canoe and started cutting one side to match the shape of the canoe. The cut side was now ready to be lashed to the frame, and after a few ties were in place (starting in the center of the canoe) I repeated the same process on the other side. I was working my way towards the front and back of the canoe on either side, making sure the skin cover had no wrinkles and was tight (but not too tight as the rawhide shrinks and tightens on its own as it dries).

Skin cover being attached to one side of the frame, with a lashing between each rib

With the skins on but still wet I decided to go for a test ride, and after stiching up a minor hole, there was almost no leaking. Since it was a hot and sunny day it didn´t take long for the skin cover to fully dry – time for the last step, the oiling & pitching of the canoe.

With the hides just put on and still wet, the canoe is ready for the first test…
…and is shown here after being dried and oiled.

Et voila – canoe finished! Or so I thought…which brings me to

Part II: Lessons

The cover was dry alright, but the shrinking action had opened up the seams too which meant the seams weren´t really waterproof anymore. What I realized then was that Inuit people usually pre-soak their boats prior to using them – this way the hide swells up around the seam and allows for no more water to come through. I decided to try another approach – pitching the seams similar to how it is done on birchbark canoes. Adding some powdered charcoal to melted pitch to help it set & harden, I covered the seams on both the inside and outside of the canoe with the mix.

Pitched seam on the inside of the canoe

As for the cover itself, it turned out that my first application of oil and pitch was leaning a little heavy on the pitch side – it kept being sticky even ater drying and therefore quickly adhere to anything it was touching -leaves, grasses, sticks…Scraping off the excess pitch and re-oiling the frame (with less pitch) seemed to remedy that.

Now…ready for the maiden voyage. There was some minor leakage and the sides of the canoe were a little lower than I had originally intended as the frame was warping somewhat during the drying process. Other than that, it seemed to work pretty well and it proved to be stable even on a windy lake. On another test ride, a stick protuding from a submerged tree trunk scraped along the bottom and got hung up at the seam, causing some leakage. Tamarack offered a practical suggestion for this particular issue – adding a keel pole to the bottom of the canoe, to protect the skin cover and seams from scraping on objects. And I can say, after going up and down creeks, through alder thickets and over beaver dams, that the keel pole truly works!

Keel pole on the upturned canoe

Something else I discovered on a longer canoe trip was that the skins do eventually absorb water (through prolonged rain or just being in the water, which, by the way, doesn´t mean that it´s leaking). And when this happens, the canoe gets a lot heavier – so heavy indeed that portaging become a lot more labor-intensive. I haven´t been able to find a way around that yet – maybe that´s just the way with skin boats (unless you use a modern varnish)…

A large gap along the seam…

Some lessons come the hard way, such as when I was re-pitching the seams after the aforementioned canoe trip. The next day I discovered that there were a number of holes along the seams. How cou that be, after just pitching it, and no prior holes? Closer examination left no doubt about it – the last application of pitch was so hot that it had melted through the hides! The lesson here seems obvious – make sure that the pitch has cooled down enough so it won´t damage the skin cover. I now test the pitch with my inger to make sure it´s not too hot. After weighing my options, I ended up cutting out the affected parts which gave me the oportunity to practice patching the boat.

…and the hole sewn up, prior to re-pitching.

Now, after having elaborated on all the “hang-ups”, I´d like to add that the skin boat is indeed a great pleasure to paddle…there´s a sense of connection and satisfaction that is unique to something crafted by one´s hands and the materials nature provides…

Resources

Feel free to contact me if you have any questions about the process, the canoe or anything related (just leave a comment and I´ll eventually get it, though it may take a while). I´d like to thank all the people who´ve been providing valuable information and suggestions, particularily Tamarack Song. Some books and websites were also particularily helpful, some of which I´m listing here for those who want to do more research about the subject:

– Skin Boats and Bark Canoes by E.T. Adney and H.I. Chappelle

– The Aleutian Kayak by Wolfgang Brinck

– http://www.bushcraft.ridgeonnet.com/building%20a%20canoe.htm

The joys of paddling…
Regards
Torjus

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7 responses so far

7 Responses to “Of skin and wood”

  1. TheWarlessWarrioron 02 Aug 2011 at 12:12 am

    I cannot express how impressed I am. That is incredible. I have often pondered making a coracle…
    All the best to you.

    Mike J

  2. Deus Ex Machinaon 02 Aug 2011 at 12:06 pm

    Fantastic. You have provided a lot of detail for those of us who have yet to try this. Thank you, in advance.

  3. Ericon 03 Aug 2011 at 11:11 am

    That is fantastic! I have always wanted to build and hide on frame boat. Nicely done

  4. Jonon 13 Aug 2011 at 11:32 pm

    Now thats a canoe….! Thanks for sharing this Thomas, a great project you have shared with us! Very inspirational!

  5. Thomason 17 Aug 2011 at 2:51 am

    hey guys,

    thanks for all the feedback. Jon, your articles on skin on frame canoes were quite helpful and inspirational too 🙂
    I may do some followup post or update after some more long-term testing and experience with the canoe…

    greetings from the northwoods
    Thomas

  6. stephen mcgowanon 20 Dec 2011 at 12:10 am

    Hey mate just a thought, on your canoe, could you water proof it with that tar substance that you get when you burn silver birch in a tin?(recepticle of some natural form) the partisans in the war used this tar on numerous objects…and i know you have plenty of silver birch. Or tapping a tree for sap?

  7. Thomason 27 Dec 2011 at 6:01 pm

    Hey Stephen,

    yeah, I definitely think that birch tar could work. It was used for waterproofing ships after all! 🙂
    Actually, where I’m at in the northwoods of wisconsin we have white birch (also called paper birch) instead of the european silver birch. The tar seems to be very similar though. I have yet to make a larger quantity of it in a “primitive” manner. The biggest obstacle seems to be having the vessels for the process (I’ve made a batch before with a couple of clay flower pots, so using primitive pottery of some sort would probably work for that). I’ve used pitch since it’s fairly easily available, and it was also traditionally used here for birchbark canoes. Great idea, I may test it out with my next skin boat!

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