I went today to look at an open 16' aluminum boat, something I've been looking for for a while, the price was right and when I got there the boat was sitting turned upside down on some logs but not covered.
It looked decent but when I grabbed the rail to flip it over to inspect the inside, noticed that the gunwale rails were all split open, some splits still had ice pushing out of them.
Being that it was left to sit upside down, a good idea to preserve the inside, the open seam of the only riveted gunwale rail let water fill up that tube area, when it froze, the rail split open like a frozen water pipe. The boat had several huge cracks along the gunwales, some nearly full length of the boat.
Needless to say I walked away but I think it's worth making note of when storing a boat upside down outside in freezing weather. I think that boat would have been better off if left upright and covered, or even uncovered and just stored bow upwards. It was an open hull with no wood, so there's nothing that would have rotted other than maybe the transom wood which was surface mounted anyhow.
I wonder how many other boats have this same issue if stored belly up?