Use some course 60-80 grit sand paper, and rough up the area around the hole on
the inside of the hull. On the out side of the hull, tape over the offending hole.
Then, working the inside, brush some fiberglass resin over the area, and press
some fiberglass matte into the resin. Overlap the the fiberglass matte at least
1 to 1-1/2 inches around the hole, and work the matte into the edges of the
hole using your brush. Thoroughly soak the fiberglass with resin as you
squeege the air bubbles out from under the fiberglass, and as much resin out
as possible. Once that is cured, you can put a few more coats of resin over the
inside patch, and bondo and finish the outside as desired.

[8D]