Poisoned wood repair?

[imported_Spissgatter W-9]

I have 34' sloop orinally planked in 1941 with fir and fastened with #14 galvanized screws. All the strakes below the water line have been replaced and fastened with silicon bronze. I'm now replacing the last 500 or so original fasteners in the remaining planks. My quandery is what to do about a few places where the fasteners have, evidently, rusted and turned the surrounding wood black. I've heard this described as "poisoned wood." I don't know if I should scarph in a section of the plank, put in a dutchman, treat with epoxy or what??? The wood appears to be as stable as the surrounding wood though stained black. Any recommendations?

[Ian McColgin]

Black but not soft? In the fir plank but frame ok? If yes to both, I'd not worry but I'd look at the area every couple years. Sounds like nothing much more than a big rust stain.

[Allen Foote]

Drill the hole with a bigger fostner bit. It will provide a flat bottom surface. Drill it 3/4's way through and then epoxy a wood plug in, using the same species of wood. The epoxied plug area will be stronger than the surounding wood itself. ;)