Moved this topic out of General Chat...
RE the corrosion - this really strikes me as odd. This is a very common place to put the battery switch - it's supposed to be water tight in those compartments. Seems to me there was an installation problem or an equipment failure; otherwise, this would be a very regular occurrence.
I'm guessing a more likely culprit is a faulty switch installation. Pat - is the switch mounted on the inside edge of the box, with the attachment bolts through the motor well edge? If so, perhaps these bolt holes were not sealed. Assuming C-Dory is using the standard Perko 1-2-All switch, if water were to get in behind the mounting bolts, it would be right on the battery cable connections.
To me, it seems water must have made it in there - I can't imagine damp air could corrode those connections in one year. Regardless, I've always used "the goo" on all my battery connections - last stuff I used on Da Nag 19 was the CRC Marine Corrosion Inhibitor -
link is here.