ya thats what it looks like to me as well that it was hit from the rear. I've had the boat 3 years and it wasn't there before. Had to of been last season. I just didn't see it until I was putting on the new fresh air exhaust. The previous years the boat has been moored for the season on the Willamette River. Last year a big log was wedge in the dock right behind the boat had to ask the owner to come cut it loose. Now I'd be willing to bet that that log hit the rudder before wedging into the dock.