Dry rot

Hooking up the aft lights in the bilge/engine room. I saw what I can't unsee! One of my ribs looks like it has the dry rot. It's going on the yard in about 3 weeks but I sure don't know a thing about rot. Burn yes, but rot no. I should add that it is about 3-4 ribs on each side in the same area. What causes dry rot, is it contagious?

That sucks! I've seen that lots of yards are using UHD plastics to sister bad ribs, I wonder if that might be a solution? You will have to remove all the rot or kill it so it doesn't spread.

Good luck with that...

Luckily it's not in the planks, I dug around with a screwdriver under the afflicted area and it's tough as nails, just the ribs

Dry rot doesn't happen in dry areas. It needs fresh water moisture and it is contagious. Cut out the rot. Sister in new ribs. Don't wait. It will only get worse.
Inspect the rest of the boat now.

First step , STOP the source of water that is causing the rot.

Probably a deck leak, but ,,,,,

Greetings,
Mr. s. "First step , STOP the source of water that is causing the rot." EXACTLY correct. There is a wealth of information on line regarding dry rot.

A real guru sent me this to help.....seems to be about what I remember from working on wooden boats as a kid....

"Re the dry rot thread, Timbor or almost any borax/borate solution liberally (and regularly)applied with a garden sprayer will help fend off dry rot spores or bacteria. It is the wooden boat owner's salvation. That and a garden sprayer full of vinegar to get ride of the sodium hydroxide created by galvanic action that dissolves wood around through hulls and other wet fittings.

It looks like that boat has some very serious rot, it takes a while to get that far along and I would be amazed if what is shown in the pics is the only place effected."