So where's the problem? Loose hinge? Mine works fine still. Can you post a pic of what's hitting and where?
I assume it's on a bunk trailer. You think there's not enough support for the keel?a friend of mine has the same problem with the same boat.... I suspect that some keel rollers might help his ... I think the boat is deforming over time...
It is for sure sagging and the first thing you look for is rot. It also could have come unscrewed from the supports that run to the floor. Just lif it up and put new screws in.