Work began on the router jig to shape the rudder.
A mock-up of the jig consists of wo pieces of 1/2" ply. I made the mistake of cutting the foil shape out on each piece separately. The two pieces don't match perfectly as the sanding belt broke (you can see where) before I finished fairing the two pieces. Used double-backed tape to hold them together while I cut the 30mm notch (for the rudder blank).
After I clean up the wrinkle in the rail, the first test effort using the trim router and the jig went okay, but not great. Neither the blank nor the jig were clamped down for the test cut. The trim router was more difficult to control: it wandered a good bit, seemingly with a mind of its own. Shallower (and therefore more) cuts, a larger diameter bit, and maybe the larger router may lead to better results.
My next trial cut went much better. I used the larger router (it has handles and variable speed), a larger bit designed to hollow & clean out small bowls and boxes; and shallower cuts. Running the router at its lowest speed, the larger bit, clamping the blank down, and gradually increasing the depth of cut produced a much better result. One thing I learned, though, is that if the rails are not perfectly faired & matched the router will not be perpendicular to the blank - resulting in slight ridges between passes.
New rails will be pattern-cut from hardwood and faired to match. Hopefully, after a few practice cuts, I'll soon be ready to shape a new foil from the full size blank.