Hi, I have discovered a bit of rot behind one of the chain plates on my 1950's twin planked keeler. Fresh water has obviously run down the chainplate, which comes down the inside of the hull, and rotted the top of one stringer and around the bolt going through the hull. I've removed the bolt, and cut out the stringer, the effected bit of the inner plank, and the rot out the outer plank. The effected area on the outside of the hull is small enough to allow me to use a wooden plug, which I plan to epoxy in place then re-drill a hole to replace the bolt. The inner plank is pretty thin, only about 8mm. The piece I've taken out is quite small - roughly 6inches (150mm) of a 6inch wide plank (it happens the piece is an odd diamond shape because i've made vertical cuts across a plank running diagonally, but that probably makes no difference. Can I use a bit of ply, sealed with epoxy, to replace that piece of the inner plank? The chain plate bolt would go though the wooden plug in the outer hull, then the ply, then the chainplate, then the new hardwood stringer. My guess is that the ply would be as strong as any timber I could put in there.