Taking lines off bow/stern for new stems

[Baconweasel]

Hello everyone...I'm new to the cedar/canvass game and I'm really happy to have found this site as I'm going to need all the advice I can get, and it looks like people here are happy to dish it out.

I became the owner of a 16' Peterborough last fall (my neighbour gave it to me in exchange for 6 custom paddles I made for him). The hull is in reasonably good shape, save the bow and stern.

The bow stem is non existent (I pulled it off with my fingers) and the stern stem has some rot just below the deck. So, I'm going to replace both completely, along with some ribs and planking.

My first task (I believe) is to replace the stems. My question is, what method do your recommend for taking lines off the existing stern stem in order to make a jig for bending and laminating new stems on?

Thanks in advance for the advice. I've already learned alot from skulking around the forums.

 

[Todd Bradshaw]

We used to take lines off of existing boats for strip-building using a rather crude, but effective set-up. We would set the boat, right-side-up on a beam (building strongback) that had been rigged with "arms" sticking straight out the sides at 18"-24" intervals and a couple running fore and aft just past the ends of the canoe. Each arm was built from 1x3's, screwed to the strongback and shaped like a rafter square, with a 90 degree angle and a vertical upright at it's outboard end. The boat was centered on the beam's centerline and leveled. Then we took a bunch of scrap strips about 6" long and whittled one end of each strip to a sharp point. Then it was just a matter of holding one of these pointy scraps against the flat side of an arm, moving it enough that the point rested against the hull and shooting a staple into it to tack it to the arm. For each arm, we would staple enough pointers that we had one every inch or two from the keel line up to the gunwale at that particular "station". Once we were done, we had an entire side of the boat with pointers stapled in vertical lines along the arms and on each end to pick up the stem profile. The boat was lifted off the beam and the arms carefully removed. We would lay them one at a time on a sheet of paper with a baseline and centerline drawn on it, align them and make a dot at the point of each scrap chunk. Using a flexible batten you then connect the dots for each station. You end up with cross-sections of one side of the canoe at regular intervals, just like the end view of a lines drawing in a boat plan. Same thing for the stem profiles, only you get a side view of them. If you work carefully, the results are accurate enough to start cutting stations and build from.

Hope this makes sense as it's a very simple process, but hard to put neatly into words. With some type of simple upright or "L" shaped structure at the end of your boat, pulling a stem profile would be fairly quick and painless. Here is a photo of a small one that I used to get a cross-section of a specific spot on one of our kayaks in order to make a trailer bunk that really fit the contour of the hull well.

 

[Baconweasel]

Thanks for the reply

Thanks for the reply. I've seen this method illustrated in "Canoecraft." It seems to be fairly accurate, so I'll give it a go.