That's a pretty fancy fishfinder for a pontoon. Nice unit but you will have to go through the additional steps of mounting the unit and a transponder and wiring for power.

While it is not nearly as feature filled, I use a Fishin' Buddy (was Bottom Line, now Hummingbird) which has the finder, transponder and power in one package. Several manufacturers sell holsters that make mounting these units a breeze. Nowhere near as nice a unit as the Lowrance, but quite serviceable.

When I really need a GPS, I carry a handheld Garmin Vista.