C-Dory Transom Drain Tube Corroded - Wet Core!

Hello fellow c-brats,
We have a c-dory cruiser 2003 up in Southeast Alaska, and it's a great boat for us. We winter the boat on the hard in Petersburg AK, but we live in another community in Alaska, so maintenance gets away from us a bit.

Before I write anymore, I will put this question to the group - is there somebody who is a fiberglass expert and also knows cdorys who I could talk to?

The full story:
Last spring we returned to the boat and had to launch on a short timeline. We discovered before launching that the brass drain plug sleeve through the transom had corroded and was falling apart. We weren't sure when that had happened, but when we took the sleeve out we discovered that the balsa core around the sleeve was wet. We needed to launch, so we did a temporary fix. We scooped out as much wet balsa as we could (we're not sure how far the wet extended), filled the void with spray foam, coated a new sleeve with 5200, stuck it in, and put splash zone around the exterior to stabilize the sleeve.

This patch is worked just fine for last summer, but moving forward we have some questions for the group.

1. Has anybody had this happen before? I will say here that the *middle* of the tube was the part that was corroded out. It almost seemed like water could be leaking from the transom sump through some hairline crack, and then the tube corroded from the wet balsa? I'm not sure there is anything to this theory, but curious if folks have experience with that transom sump failing.
2. How concerned should we be about wet balsa? Is this worth trying to fix, or is this just a problem of a 20 year old c-dory? We don't know how far the moisture spread.
3. Should we hire somebody to do fiberglass work on the transom? The thought here would be to cut out a chunk of the outside layer of glass on the transom, replace/dry the balsa, and then patch the fiberglass, put in a new tube.

Thanks c-brats!!

I sent you a private message. I do suggest that the entire transom be assesed for water intrusion, which is likely. If there is wet core, that should all be removed, especially since the boat is subject to freeze thaw cycles. I suggest that it be opened up--The scope of what to do next depends on what your testing reveals. There is a good chance that the entire transom core will need to be replaced. Some of this may be balsa or foam--but most will be plywood or coosa board--some could be prelaminated fiberglass in some places. The corrosion of the tube is unusual, but I have seen it happen previously.

The original drain plug on my CD22 was too high to drain the sump adequately. I added a new drain lower down and used a plastic tube instead of a metal one.