So, I'd been hearing something clunking around back and forth when tacking. Stuck the camera down through the inspection port and got this pic: some PO had left a socket wrench in the bilge! There sure aren't any sockets missing from my toolbox ...
... now how am I gonna get *that* thing outta there? It's sitting just forward of the CB trunk. Maybe a magnet? It's obviously been in there awhile, and I've only heard it recently, so it must have been stuck in some nook or cranny under there all this time ...