We ran aground on our H18 this year and mangled up the bottom of one of the dagger boards pretty badly. The material was chipped out and the board was split down the seam. I'll try to describe the repair process, sorry, I don't have any pics.
- First step was to grind out the damaged fiberglass with a dremel tool and chip out all the broken filler material that is used along the seam where the two halves of the board are bonded together. I used a small flat blade screwdriver to chip out as much of the damaged material as possible. This left a gap of about 1/16" between the two halves of the board down at the very bottom.
- Next I laminated a few plys of fiberglass roving on a sheet of wood to make a filler panel/spine. I used 18 oz woven roving and polyester resin. Once this fiberglass sheet was cured, I cut it to shape so it would fit inside the gap between the two board halves. I left it a little proud so it could later be sanded to shape. I fit the panel inside the board and then drilled through the bottom of the board and the filler panel so I could pass four #10-24 machine screws through the board to clamp the whole mess together.
- Then I used epoxy to glue the filler panel into the bottom of the board, I installed the machine screws and nuts to clamp everything together. After an hour or so, while the epoxy was still "green", I removed the machine screws.
- After letting the epoxy cure overnight, I filed the filler/rib to shape. I sanded back the existing gelcoat/fiberglass about an inch or two from the damaged area. Then I filled all the fiberglass voids (and the holes from the machine screws) with Formula 27 filler. After the Formula 27 cured, I sanded everything smooth with a sanding sponge.
- Then I laminated 6oz fiberglass to each side of the board using polyester resin. After it cured, I sanded lightly and then filled all the imperfections with Formula 27 and sanded fair with a sanding sponge and then wet sanded up with 600 grit paper. I have yet to paint/gelcoat, but that would be the final step.