Adam, thanks for your suggestions. I, too, thought that the moisture was coming from the through-hull fittings. But, the strange thing is that this area has the least amount of moisture, while the upper port side of the transom pegs the meter.
The boat has never been in the water. It's always been trailer-sailed. I would suspect the hull to deck joint based on where the most moisture is found. But the joint seems tight with no obvious voids.
There was quite a bit of water in the bilge some time after I got the boat home from Florida where I bought her. It had rained hard on the trip back to Georgia. Perhaps that is the source of the moisture in the transom. I have dried out the bilge, and will make sure that the boat stays dry.
I'll just monitor the situation for the time being.
