Hard Ride with half fuel

[Jpilot]

I have a 80' 23 CC with a full transom and Armstrong Bracket. If my fuel get's below half, The boat will ride very hard and pound in a head sea. It never had this problem before I installed the bracket. I am wondering if my fuel tank is too far aft for the change in configuration. I am thinking about putting a portable water tank that I can fill with my washdown pump and put in the fish box while offshore to add ballast. Has anyone else had this problem? Looking for suggestions.