Help! Inside Rib (with some decay?) refinish / patch

I can't believe this is a first. I hope some of you have experience that will help.
I figured my OT HW canoe would be watertight inside and out and left it outside and right side up for some weeks last summer while the garage was full of other stuff.
When I put it away, I noticed that one rib near the middle was darker than the other nearby wood. A little probing with a fingernail and I broke through the varnish into some soft, wet wood. Using just my fingers, I peeled off the loose varnish so the wood could dry and hung the canoe in the garage for the winter.
I'd say I have a patch about 20" X 2" on that rib that is bare or has flakey varnish and needs to be protected.
The rib is soft. (although I cannot remember how hard they were when they were all stripped) Does that sound normal or does it sound like dried decay?
Given that I am not going to replace the rib;
Should I put some sort of hardener or stabilizer on the rib? What kind? Before or after a gentle sanding?
What else before I add layers of Interlux Schooner?

 

CPES would be a good product to solidify and stabilize it if its getting punky and soft, but you'll want to strip it down to expose the wood.

 

Thank you, Andre. I'll order some and get to work.

 

I haven't used the CPES that Andre recommends, but I did try GitRot, a thin epoxy also used to stabilize partly rotted wood. I was not impressed by GitRot. What worked better for me was to thin the regular West Systems epoxy 105/206 with 10 - 15% by volume acetone to produce a somewhat runny epoxy. Obviously you have to get penetration inside the rotten wood for any resin to do any good, and if the wood is extremely dry, penetration tends to be poor. What helps is to 'wet' the dry wood by brushing it with acetone just a minute or two prior to painting the thin epoxy over the top. Wait long enough for the acetone to penetrate the dry wood, but not long enough for it to dry out again. Tom McCloud

 

I have used cpes once. I like it and am going to use it again soon on a ChrisCraft Kit boat exterior. Excellent product.