I went with the hot-coat
i did some quick research, and applied a coat of resin (polyester) with a little extra hardener. hopefully it sets up good and hardthis whole job is a pile of not-fun..replacing a rotted out section of a bulkhead. I guess it would be less fun if I was replacing the whole thing (the glassed-in battery tray was apparently FILLEd with water. I dropped my battery about 8" onto it (reaching way down into the lazarette) and it smashed through all the way to the bottom along with a lot of water!! The bulkhead adjacent to the box was all rotten down low.I cut away the rot, dug the fiberglass tabbing clean, and cut my plywood to fit into the tabbing snug with the old good wood. I'll extend the tabbing up another 4" to cover the seam, and all should be good. I also move the battery box! (perhap I will post a photo album?)