I stumbled onto this webpage with a simple description of how to make a foil with a router- no jig required. And it made a great deal of sense to me.
And then great things started to happen.
Brief summary- After consulting the plans to figure out the shape of the foil, we made a list of offsets to mark on the blanks. We basically broke down the centerboard cross section into measured increments, a bit like a topographic map.
After we had all the lines marked, we used the router to cut out each section.
Then I used my block plane to smooth it all out.
I'm quite pleased with the cross section- it's starting to look like a foil! I'm finally heading in the right direction.
I'm a long ways away from being finished with it, but I foresee great things in this centerboard's future. Plus, it's the last of my 3/4" Okoume, so I had better get this one right.