I mounted my Humminbird 587HD DI to the starboard mounting boards trailing edge on a RAM mount. I ran the wires just under the edge of the mounting board and entered the hull there. The transducer is mounted to a Mad Frog Transducer Deployment Arm and is bolted to the mounting board just in front of the RAM base. When I'm done using it the arm folds up and swivels into the boat laying just along the inside edge of the "gunnel" so that it's protected from catching onto anything when sliding past trees or into the back of the truck.
I'm using a 9amp/hr 12v sealed battery that is kept inside the hull in a small dry bag and is accessed by removing the storage bucket under the center hatch. The system has worked great for me so far!