Hi Robbin, I had a similar problem when I re-furbed my M15 last winter. Mine looked like the center board may have broken and dislodged the epoxy holding the liner to the bottom of the keel. After I dropped the center board out, I could see that this was not a major problem. The area ranged from small chipping to about 1/4" in size like yours. This area was about 18" long on each side of the trunk. I took a small grinding tool and expanded the area. I used Bondo to fill the area. After the Bondo set, I faired it and applied bottom paint. The fix is now 14 months and looks as good as new.
Norm Bundek M15 #172 _______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
