I have a 5hp nissan motor on the back of a 240. I am considering adding an electric trolling motor as well, to aid movement while fishing. The transom is full with motor and depth finder. My choices are either extend the transom or mount the trolling motor on the rudder. The trolling motor could be lifted out while sailing or moving under power of the gas engine. Thoughts, anyone? Any thoughts of where to put an additional battery? I have thought if in a battery box, and away from the gas tank, that locker would be fine. Battery close to the center line and gas tank almost in the open by the transom.