I didn't use chain saw per seacast instr. I used a 1/2" x6' long galvanized pipe sharp 45 angle one end. And a homemade scoop out of 3' long 3/4" pvc pipe x 3/4 90 x 10" pvc pipe cut in half 8" in middle- each end of 10" piece left round. Used scoop to remove rotted junck otherwise hard to get out.

TO ANSWER YOUR ???; I scraped the remaining plywood stuck to the inner and outer skins with a scrap piece of the chain length fence tube the 1-1/4" dia piece used horizontal for the top of the fence. cut at 45 angle. This 1 1/4 tubing worked well for scraping the sides of 1-1/2 " thickness space of hollowed out transom.

think I was able to send a personel message cell #.under MY STUFF @ TOP OF main TFF home page