GWDawg1, I don't know if it will even work. We make a cable for the Magellan Sport Trak and Meridian to direct connect but I do not know if your Explorist uses the same (Magellan) connector as these do. If not, you would have to buy our AS-HHGPS cable and Magellans connection cable than wire them together. If the Explorist has an NMEA 0183 version 2.0 or higher output that is at a 4800 baud rate, than it should work - although I so far have not been contacted by someone who has done this.
If it does connect up and work, than the Humminbird unit wil treat the Explorist like a GPS antenna. It will only get position, speed and heading data from the Explorist. Waypoints, maps and the like will not be transferred from the Explorist to the Humminbird.