pretty hard to do with the drive on the boat? maybe I'll drop the lower & give it a beating with a BFH

I would think it would be easier with it on the boat that way you don't have to try to hold it.
just chain it off the wall in then cheney other side of the wall and start tightening it like a wishbone and just wack it. (while under pressure ) it sounds really messed up but that is the best way to move the metal