Question on re-coring cap rails

[zendora]

My cap rails near the aft part - around the rod holders - are soft. I am attempting to re-core them from underneath so I don't have to take the entire cap off. This would be a massive project beyond my skill level, and I think I'd have to cut somewhere across the forward bulkhead to get it off (Savage). Removing the cap is not an option at this point. The sections I'm repairing are roughly 3 feet long by the width of the cap rail.

So far I have removed the old fiberglass skin on both sides from below and removed most of the rotten wood. I think it was balsa core. There is one section of plywood that held up a lot better - wet but not rotten. I have not removed that section yet, as it's in there pretty good.

My plan for the re-core is to use 3/4" marine ply with some thickened epoxy and cover it with 6 or 9 oz cloth. The good news is it doesn't have to be pretty, at all this is being done on the underside of the cap rails. I'm planning on holding the new wood in place with either some big clamps, or with a bottle jack and the tire jack from my car while the epoxy cures. At this point I'm looking for some suggestions and constructive criticism. Any tips on getting the wet plywood out, prepping the surface, holding the new plywood in place, materials to use or anything that will make this project easier?

I'll post some pics this weekend.

Thanks,
Mike