By Jerry Cronan

Putting a backer plate in an inaccessible area

Here is how I fixed an unwanted hole in the transom of a foam-filled boat.

1. I drilled a ½” diameter hole on each side of the unwanted hole,then used a saber saw to connect the holes to form a slot.
2. Next, I cut 4mm thick plywood into a football-shaped backer plat that would fit through the slot the narrow way. I attached strings to the plate, coated it with epoxy then slipped it through the slot.
3. Using the strings, I turned the plate so that it covered the three holes and the slot. Reference marks on the plate helped me get it in the right position.

Plywood backer

Mounting a cleat

This same basic method worked well for mounting a much needed cleat on a balsa cored deck. There was no access to the back, so it was a seemingly impossible operation. Here’s how I did it:

1. I used the cleat as a template to bore and tap an aluminum back-up plate. Then I used the plate to mark oversized holes in the deck.
2. I drilled the screw holes and cut a slot in the deck, centered between the holes holes. This slot passed all the way through the balsa core deck and lower laminate.
3. I used a small wire to fish a string diagonally through two of the holes in the plate and the matching holes in the deck.
4. I coated the plate with epoxy, pushed it through the slot and used the string to finesse it into position under the deck.
5. I used a syringe to coat the top of the plate and fill the slot with thickened epoxy. Then I coated the bottom of the cleat and mounted it in position over the holes. I threaded the screws through the cleat and deck into the two plate holes without strings.
6. Before tightening the screws, I pulled the string out, then put the remaining screws in the holes where the string had been.

(top) Drilled and tapped holes in the aluminum backer plate. Slot through the deck to accept backer plate. (bottom) Thread two bolts into the plate through cleat and deck. Coat top of plate with epoxy before mounting cleat.