The Ben Hur
The only sternwheeler named Ben Hur, in the Way Directory, was built in the Knox Boat Yard in Harmar, Ohio in 1887. She carried a circus in her first year, and spent from then until 1904 generally in the Pittsburgh - Parkersburg trade. In 1904 she was sold and sent to St. Paul, Minnesota, but was sold again, and spent 1912 and from then until she sank in 1916, ran in the New Orleans - Bayou Teche route in Louisiana.
Why a boat that spent virtually none of her life in or around Maysville should appear on Maysville postcards, we don't know.
The information above, as well as everything else you ever wanted to know about steam boats on American Rivers, is in Frederick Way Jr.'s encyclopedic Way's Packet Directory, 1848-1994, from the Ohio University Press. That's him at left, and he's famous in steamboat circles for his encyclopedic knowledge and vast collection of steamboat matters.