Wednesday, August 27, 2008

Building a Cedar and Canvas Canoe : Wednesday

Wednesday was all about planking. No doubt about it.

The first planks to go on are the garboard planks. To get them to conform to the contour of the ribs, a swab and hot water are used to make them flexible. At this point, the planks are about 3" wide and 5/32" thick and are from Northern White Cedar. Ideally, the planks are full length, but in this case the longest we had were about 10'. We selected planking carefully to put the knots behind the ribs. Where the planking was joined, it was cut at a bevel and the beveled joint was hidden behind the ribs. At the ends of a plank, small holes were drilled into the planking, but not the ribs. This was for the tacks so that the ends of the planking would not split. Brass tacks were driven through the planking and the ribs and clenched on the steel bands covering the forms. At the ends of the garboard, we drilled into the stem and drove bronze ring shank nails. At this time, only the garboard is attached to the stem.

Pay particular attention to the orientation of the tacks. They run diagonally to make the planking lay down on the ribs properly. In this image, the second plank is already in place on both sides and the plank ends are trimmed back to the stem.

More planking - note the wet areas and that the ends of the planks are neither trimmed nor tacked at the stem.

There comes a point at which it is necessary to 'gore' the planking. Basically, this is where the ends of the planks are tapered to get the planking to fit on the hull. The goring pattern for the planks can vary from hull to hull (i.e. which rib you start at, the number of goring planks, how far up from the garboard, etc.) and is somewhat of an art. On our canoe, there were three gored planks that were full width amidships and tapered out to the width of one plank in the quarter ends. In the picture below, you can see the third plank being prepared for goring. There are pencil marks that have been made using the metal underscribe gage that is on the sawhorse. After the lines are marked, they are roughly trimmed using a utility knife and finish fit using a plane.

Here is a picture of the finished goring and the plank that meets it at the end quarter. The diagonal tack pattern is very apparent here:

The ragged edge of the bottom plank would be taken care of once the hull was off the mold on the following day.

This is where we ended the planking process for Wednesday. After this was finished, we went and cut Mahogany for the outwales of the canoes.

It was both fun and very satisfying to see the work progressing so quickly.

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