I was working with a very experienced and smart composite technician today to check out a crack in the gel coat in the bilge of our J/109.
I was pretty sure it was not structural and just the result of sloppy gel coat application but wanted a pro to check.
He sounded it with a hammer, just like anyone would, but then put his hand down as shown and explained that if there is a void he will be able to feel “bounce back” when he taps. Never seen that before.
Good news: all is fine. He figures someone just poured resin in to level it. Seen it before. That said, he is going to grind it out and repair it right with cloth and then brush gel coat.
Says it should take about half a day. The good guys are fast, too. If I tried it, it would take half a day to get the resin out of my hair, never mind the repair.