Three different work sessions, somewhere around eight hours in total for a guess to scrape, power sand and hand sand the interior of the hull. I finally have it in pretty good shape and think I’m at the point I can switch out of the coarse grits (40 & 60) and start moving to the finer grits (80 & 120) to further smooth and refine the interior. No new processes or techniques, just more of what was done on the outside. The inside curves do make this more difficult and the ends have to be done by hand as you can’t get a random orbit sander in there.
In the above images you can see the progression from rough to fairly well blended with a reasonably smooth surface. In order to sand it adequately I was wrapping sand paper around pretty much any shape I could find to fit the various profiles, including just using my fingers.