I put fiberglass over marine plywood allowing for about a two or three inch overlapp on the adjacent fiberglass in the boat. The pictures previously shown are the result of putting a coat of fiberglass on the underside of the deck ... a literal pain in the neck. In putting the fiberglass over the patch and then applying it I do not have to worry about holding everything up. To hold the patch up I got toggle bolts that will go through the holes that were already in the deck from the hardware. When tightened they firmly hold the patch firmly in place without having to prop from underneath.

Patch for shroud anchor