After sanding the lower hull ( bottom panels, top sides and transom ) with #80, I applied the 2nd ‘filler’ coat of epoxy to the bottom panels and the transom. The sanding took about 4 hours yesterday.
I finally cut the rabbets (aka rebates) in the mast staves. I used a 8 mm straight bit in the router set to a depth of 9 mm. Three passes along each edge made it a straight forward job in the end, with the guide (fence) set in increments of about 6 mm for each pass. This was a scary thing to do nevertheless. Wrecking one of the staves would have been a bad thing – making a new stave would be a lot of work and $$. In one of the photos you can see a scarf. The scarf in the other stave is about 2′ further towards the top.