The spar for the side fin is being made.
The spar straps, made from Sitka spruce, are laminated, and the ribs are glued in place to form the tapered structure. Now the ends still need to be cut to taper as well. No problem for a 5-axis milling machine. Unfortunately, I don’t have one of those in my workshop. The solution is a jig where the spar can be clamped in such a way that it can be rotated and symmetrically tapered on both sides with a router. The result is perfect. However, as always, the time spent building the jig and setting it up accurately takes longer than the actual milling work.