Grandpa has a 13ft smokercraft that he uses as a cartopper and trailer boat. He used the portable unit on that and since it served as a cartopper that was the easiest setup for it. I have a 14ft Herter's that is too heavy for a cartopper(which is why grandpa got the smokercraft). Both boats have 15hp engines. Since it just sits on a trailer I installed a Humminbird unit with two transducers and the speed/temp sensor. In fact I bought it off this site. The head is on a Ram mount epoxied to the side of the boat and one transducer and the temp/speed sensor are epoxied to the transom. The other transducer it attached to the trolling motor. Since I bought mine used they where about the same price or maybe mine was cheaper. Grandpa's is more portable, simpler to install, takes up less of the transom and probably simpler to use. Mine runs off the trolling motor battery and works at any speed.