Boat Buzz

Just about done the rebuild of my 2 K engines (will share pics soon). Inspected the hull and found the keel needs some work.
Besides scraping/sanding/primer/cotton (if wider than .25in), what should I use to replace what previous owner used?
Thanks in advance for any input

Hi, I just saw this post and wondered if you had decided how to repair those areas. I'm in the process of repairing similar damage on my 36' Corvette and was curious what you decided.