I returned home from the northwest in early September and, inspired by the work of Bertram and Erik, set to work with renewed enthusiasm on the backbone. Although the pieces were all bolted together, and had been fashioned such that they properly defined the shape of the hull in profile (i.e., from the side), when viewed from the front or back, they were still perfectly square. The hull of this boat tapers to a narrow edge at the bow, stern, and at the bottom of the keel, however, and so the backbone would have to be tapered as well, since it defines all of those surfaces. This was done by drawing lines that defined the limits of the backbone's taper, and then making guide cuts with a hand saw between them, as shown in the photo above. After that, I chiseled, planed, and finally sanded the timbers down to their finished surface:
This process then continued for the entire length of the backbone, as shown. Note that the starboard side, facing the ground, remains untapered:
The stern and forefoot proved particularly challenging, since the sections there, in addition to tapering, have a substantial degree of concavity to them. To shape this accurately, I made plywood patterns of the curvature of the outside of the hull at each section, and used them to dig trenches in the wood, frequently checking their depth against the pattern:
You can see the faint "ghost" of an earlier trench at the left of the image.
Once the trenches were made to the appropriate depth, I then removed the excess material in between. Dad lent me his adz for this, which is a wonderful tool for quickly removing big gouts of wood - you just need to be careful not to take off too much!
After the adz, it was back to the hand plane and the sander, until the trenches just barely disappeared, and the surface was finished smooth:
The dark coloration is due to linseed oil, applied to keep the newly-exposed wood from drying out too quickly, which causes surface cracks known as 'checks'.
Then, with one side shaped, naturally I had to flip the entire assembly and do the whole thing all over again:
By the time I'd finished with both sides, the weather outside was beginning to get chilly, so I covered the project and retreated indoors to draw out the shapes of the eventual hull framing, which I'll discuss in a subsequent post.
