I had though of coaching you through a mezzanine project on that. I am sure the steel frames would easily support the load. You could hang a "room for let" sign out side to and collect added gas money!
I appreciate the invite to use a room let alone a place to keep a boat. I'd be ashamed of parking my rust bucket trailers and dirty boats next to your collection! But .. I'll suck it up!
I have wanted to play on the river for some time. One of these days!