While tidying up the bottom edges of the planks, I spent some time trying to get a nice, sharp, crisp edge - because that's how I thought the edges should be… and struggled with the bumps and hollows. Then, while checking the Building Instructions for something else, I (re)read this:
Tidy up the underneath edges of the planking. This is critical to the boat's looks. Use a wooden batten around to indicate the bumps and hollows. Plane the edges fair with a rebate plane (or small block plane), fill the undersides and round them as shown on sheet 6. (emphasis added)
The wooden batten certainly helps but what surprised me most was that rounding over the edge made the the bumps and hollows visually disappear. This photo sequence illustrates this effect:
The raw edge:
Planed & Rough Sanded:
Of course, there is more work to be done on the edges, but the modest statement, "This is critical to the boat's looks." is clearly an understatement. And rounding over the edge is a brilliant optical illusion - at least for me.