Complex sentence: The "Col. James M. Schoonmaker" sailed from 1911 to 1980; she was first owned by the Shenango Furnace Company, under her present name, but was then bought by Cleveland-Cliffs Iron Company, which renamed her the "Willis B Boyer".
Split into simpler sentences: The "Col. James M. Schoonmaker" sailed from 1911 to 1980. She was first owned by the Shenango Furnace Company under her present name and was sold to the Cleveland-Cliffs Iron Company, which renamed her the "Willis B Boyer".