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scepticus
03-28-2005, 05:43 PM
I'm itching to build a boat...

I like the poo duck (what is a poo duck anyway?) for various reasons but I don't like glued ply. So, starting with the belief that I can do just about anything, I started a conversation with myself that went something like this:

why not build the poo duck with real wood?
because the planks are too wide, I'll never find lumber that wide.
ok, so maybe I could use more narrower planks.
but then I'd have to re-line the planking.
no problem... I can do that... I think.

So, I set out to do just that. first I smoothed out the midships frame, kept the sheer line as much as possible, kept the profile as much as possible, kept the shape of the stem, smoothed out the flats on the transom and carved a half model at 1" == 1'. Happy with that, I took measurements off the carving, and lofted a 2" == 1' version and then sort of built that with scaled down "lumber" to see how it might work. Here's what I built:

http://www.imagestation.com/picture/sraid162/pc1c0e1181b8658925cae2292cd014767/f4ac079e.jpg

I left the building molds in place to help hold the thing together. In the real version I plan to use bent oak ribs.

assuming I get this right, more pictures can be found here test model (http://www.imagestation.com/album/pictures.html?id=2128895100)

Now, aside from all my tools being way too big for this project, everything went pretty well, but it did raise a couple questions...

The planks are more curved than I'd hoped, which I worked around by scarfing straight planks at an angle, but that in turn introduces more scarfs than I really wanted and not placed ideally. So, with a 12-to-1 epoxy glued scarf is this a real problem? If so, I'll restart my search for the right boat to build.

btw: the model is built of cypress because that's what I had on hand. The plan is to plank with atlantic white cedar.

Frank Wentzel
03-28-2005, 05:56 PM
Assuming you can handle the notion of a thousand or so rivets (I know I'd never finish the job) you will probably have to increase plank thickness. One of the best features of plywood is resistance its to splitting. To achieve equivalent split resistance plank thickness, and weight, will have to increase. I admit, I love the appearance of thousands of rivets; I just know that I don't have the perseverance to finish such an undertaking.

/// Frank ///

scepticus
03-28-2005, 06:04 PM
based on scantlings of other clinker boats about the same size, I'd figured on plank thickness of 7/16 or 1/2 inch. In my model they are 3/32".

L.W. Baxter
03-28-2005, 07:11 PM
Neat project, scepticus!

Have you considered edge-joining your narrower boards to make wide planks? Properly glued with epoxy, the wood will split before the glue-line fails. If done strategically, you might not need scarphs at all.

Paul Scheuer
03-28-2005, 08:35 PM
Not crazy at all. What would really be outside the box would be to get your lumber out of a curved log smile.gif Edge joining sounds good too. (No scrap)

scepticus
03-29-2005, 03:53 PM
curved lumber from curved logs sounds perfect, but I was assuming that I'd be unlikely to find lumber with the right curve... although now that I've built the model, I have the approximate plank shapes and can scale up some patterns to take with me when shopping for planking stock in case I get lucky.

edge-gluing might be ok, but it even if I found a really wide straight board, cutting a very curved plank out of it would create a lot of short grain at the ends where the bend is greatest.

Curved lumber... either natural or scarfed... seems better than edge gluing.