You have no idea what a great buy you made. The hours spent in that boat with your little buddy will help shape him into a great young man. My kids are in their 40's and we still hunt and fish together as well as my grandkids.
Wish I could hear a tape of your discussions out on the water.
Don't understand why one would want a system set up like that?
Because sometimes the batteries aren't mounted near enough each other to run a short jumper , so they take both wires up each side of the boat and make the 24v up on the plug.