Thursday, April 24, 2008

Creating Stem Pieces and Headboards

After the canoe's ribs were done, I set out to shape another of the canoe's key structural components - the stem pieces. In my model, I purposely chose a very simple stem piece style with a slight curve in the bottom and a nearly upright vertical rise. This is in contrast to a lot of old style Algonquin, Ojibway, and Fur Trade canoes which had elaborate stem pieces and required much more skilled craftmanship. Both Jim Millers's DVD and C├ęsar's Bark Canoe film show old school Algonquin recurved stems and seemed a bit too intimidating.

Instead, I elected to go for an Abenaki syle that was quite similar to the stems of modern touring canoes. A nearly vertical stem profile would mean better tracking ability and the limited curve of the stem would mean less likely breakage - a concern after my disappointment in attempting to carve the gunwales. Adney's sketch for this stem also revealed that it is inverted compared to most others. In otherwords, the solid end of the stem (white part) protudes slightly above the gunwales with the split end (dark part) of the stem is embedded on the bottom of the boat all supported with a thin headboard under tension squeezes below the gunwales. Most stem pieces feature the solid portion on the bottom, with the laminated part of the stem at the top, cut flush with the gunwale cap.

The process started by using my poster-sized, quarter scale bluprint from Adney's book and crudely tracing the image of the stem piece on paper. This was then transfered to a corner of the building bed with transer paper and ¼" holes were drilled around the shape to fit some spare dowels provided by the kit. This would be the "form" around which the stem pieces were bent into shape.

Marking the dowel holes; Completed bending form

The stem pieces were scavenged from strips of broken gunwale stock that snaped during the early carving process. I was able to use a piece of appropriate dimension & horizontal grain to make 4 stem pieces in case any broke during bending. Each would be split nearly 2/3rd of its length into 4 laminations to accomodate the curve. Once these were done they were soaked in boling water to soften the wood and begin the bending.

Scavenged gunwale piece; Near horizontal grain; Split stem pieces in boiling water

Carefully, a selected piece was bent around the frame and the bottom tied off. In a full sized model, the traditional material for this is basswood bark. Since this wasn't provided by the kit and I didn't want to use any split spruce root (in case I ran out for lashing), I ended up using non-traditional waxed linen thread from left over leather-craft projects. It worked perfectly and helds its knots easily without slippage.

Wrapping the stems and bending on the form

With the two stem pieces drying out I turned my attention to making other structure - the headboards (aka manboards, shoulderboards, struts). Various styles exist, some straight, some curved. I wanted to keep mine simple so carved a basic vertical structure similar to most old style Algonquin canoes. The bottom has a rectangular "legs" that fits over the stem piece tightly while the top has "shoulders" and a round "head" to squeeze under the inwales. The whole structure gives the ends a rigid structure while also helping to lift the gunwales at the ends. I decided to try a practice one first in case I had more cedar distasters. With that ok, two more quality blanks (1/8" thick) were prepared and carved out.

Practice headboard and two cedar blanks

I won't be able to insert the stems pieces or headboards for a while (at least until the bulk of the canoe a sewn up with spruce root), so in the meantime I'll be carving other parts like the permanent thwarts and sheathing.

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