A friend was over last evening and I showed him my birds mouth router bit set. Curious to see how it all works, we took a couple of scrap pieces of pine and set up the router. Both of us were pleased how nicely it fit and what possibilities these bits open up for building things.
To avoid any unevenness on the thin edge of the cut, I might set it up so theres a bit of a tongue left over (as in picture) after cutting and fitting to be planed off in the rounding process. I sketched out my mast dimensions as well as the boom and gaff.