Building a better leeboard (p3)

After jointing, ripping, and laminating the raw cedar lumber into a composite blank, it was finally time for the fun part - turning it into a foil. I planned to do this by hand and was expecting to a long and 'character building' process involving toiling into the night every day for a week. Fortunately, I was wrong and we were able to pull it off in one afternoon. Here's how we did it:

First we trimmed down the oversize blank, picking the part which was the most flat. Then we used hand planes (a scrub plane and a jack plane) to rough down the high spots, remove all the epoxy blobs on the surface, and make one face of the blank completely flat. Surprisingly, this only took about a half hour. Trent sharpens his planes using the 'scary sharp' method (sandpaper on glass) which I'm sure had a little bit to do with our success. 

Next we picked the end of the blank we wanted to be the leading edge, and planed it flat relative to the joint lines between the sticks. This allowed us to use the flat front face as a reference to align and glue paper airfoil templates on the ends of the blank. After measuring the size of our roughly finished board, we decided to go with a NACA 0011 (we lost a little too much material for 12% thickness).

With the templates in place we then went to work fairing down to match the airfoil profile. This was much easier at the leading edge since you could quickly see the material being removed. The trailing edge required a lot more wood removal and a lot more 'character building' but wasn't so bad. After finishing the top surface we flipped the board over, using a couple 1x4's as shim blocks to allow us to clamp the board in place. This was tricky since the board got more flexible as we removed material; too much clamping could warp the board and cause us to take off too much material at the center of the board. Despite it being a little trickier, we also knew (a little better) what we were doing so it went faster the second time around. After another hour and a half we had a big wooden airfoil.

 As evidence of our hard work I took this photo of the shavings produced in one afternoon. Looks like a home for a really big hamster.

The next step is to cut the board into the desired final shape (with a rounded tip and contoured handle, of course), seal out the board with a layer of 9oz fiberglass, and build in an epoxy sleeve which will accept the pivot bolt from the hull. The easy part, in other words. Hopefully more photos and notes to post shortly!