Yes, super fun. My arms are tired, and my neck hurts from looking up so much. Crazy, right? But hey, when you want to put on your third layer of 4mm marine plywood and you are using sheets that are 4-8 feet long and 24 inches wide, screwing is the best way to go.
I was driving ~150 lathe screws for every 2’x12′ section, and trying to run 4 sections a day. The next morning I would take out 600 screws and then put in another 600 for the next sections. It was a good workout for my Makita cordless drills.
After this layer on the midship I should have enough meat under the pneumatic stapler to get a good “pull” from each composite staple. I couldn’t say that at layer 1 or 2.
Next on the interior, I’ll start stripping the hemispheres with 1/4 inch marine ply, which should be roughly the same thickness as three 4mm layers. A little sanding layer, and I expect I can start running strips back and forth across the ends and the midship to strengthen the interior hull.