Thursday, September 17, 2009

Building Ravn's backbone

After taking the two stems out of the laminating form and cleaning them up with the jointer and table saw, I clamped them in the full upright position on my workbench to look at them and figure out what to do next. They were beautiful! The sweeping lines really gave me a hint of what the bow and stern of the boat would look like.

Using a large square I started to figure out where important landmarks were on the stems. I marked the waterline and where the top of the sheer would land. I also marked the positions of frames 0 and 2 on the bow stem and 10 and 12 on the stern stem. While still clamped to the workbench, I positioned the two frames on each stem. I glued them in place and, to keep them square to the bench, I glued and screwed a knee brace to each. Finally, on each assemblage, I epoxied the main deck beam to the frames and to the inside of the stem. I made the deck beams from some old-growth fir I've had for years, the grain is amazingly tight. When I unclamped them from the workbench, the stem and frames were solid.

I then built a building form that had to be straight, strong, flat and level. This is one of the frustrating things about building a one-off boat: you do a lot of work (like lofting, pattern making and form building) that that is not part of the boat and you never use again unless you build another boat to the same design. You can't fudge on any of these things, though, or your boat just won't turn out right. I absolutely wanted Ravn to be the best boat I could build. When I finished making the building form, my neighbor, Ray, and I spent the better part of an afternoon making sure it was level and true.

I then clamped the bow and stern assemblages to the building form and took a final measurement for the keelson. I cut a scarf joint into each end of the keelson and epoxied the backbone into one piece.

At the center of the building form I raised the mid-station, which I cut out from the plywood I lofted the boat's frames. I covered the edges of the plywood with cellophane tape so I wouldn't accidentally glue it to the inside of the boat. I also epoxied in the two oak frames and frame number 9, which goes only as high as the thwarts and will become part of the stern seat.

Ravn's skeleton was complete! You really got a sense of what the finished boat would look like: her size and shape. It was at this point that my friends and neighbors thought I was really building a boat. It seemed like I talked of nothing else for the past year or so, but it wasn't until they saw the complete skeleton that they were convinced.

There was a lot of work before she was ready to be planked. I used a 16-foot batten to determine the proper angle of the plank lands and the bevel on the keelson. It took many hours working with a handplane, a small handsaw and a one-and-a-quarter inch chisel, to get things the way I wanted them. Now I was ready to plank.

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