Cutting out the insides. I'll trim to the line on the bandsaw or else with a sanding drum. Still undecided.
I bought a 5X5 sheet of Baltic Birch but had a foot ripped off one edge so I could fit it in my vehicle. This section is going to present a challenge or two.I started sawing around the coaming section until I was running into the base. Then I set 2X4s under the birch to get clearance for the blade and support the cutoff when it separates.
View from the end of the workpiece. I decided NOT to cut out the centers of the coaming rings until I get the outside edges trimmed to the line. I can always cut out the centers later I haven't discovered yet how to unbreak stuff.