The houseboat River Explorer, featured this past Friday, is 61 years old and possesses a very unique history. Originally named Shamrock, it was built in 1955 by Grafton Boat Works in Grafton, Ill. Renamed Jay-Dee, this vessel became the corporate houseboat for the John Deere Company of Moline, Ill., where, for four decades, it entertained many guests on the Mississippi River near the Quad Cities. The original gasoline engines were replaced with John Deere diesels, which are now 45 years old and still running. John Deere passed the boat along to the river cleanup organization Living Lands & Waters, which later sold it to Winona State University (WSU) in Winona, Minn., where it again became a familiar sight on the Mississippi, carrying students on river education and ecology trips. WSU eventually took it out of service and laid it up at SkipperLiner Industries in La Crosse, Wis., which is where Capt. Carl Henry discovered and purchased the boat. He keeps it at nearby North Bay Marina in La Crosse.