SS St. Marys Challenger  The SS "St. Marys Challenger" is a freight-carrying vessel operating on the North American Great Lakes built in 1906. Originally an ore boat, she spent most of her career as a cement carrier when much larger ore boats became common. After a 107-year-long working career as a self-propelled boat, she was converted into a barge and paired with the tug "Prentiss Brown" as an integrated tug-barge. Before conversion, she was the oldest operating self-propelled lake freighter on the Great Lakes, as well as being one of the last freight-carrying vessels on the Great Lakes to be powered by steam engines. The vessel was launched on February 7, 1906, by Great Lakes Engineering Works in Ecorse, Michigan. The shipyard had received an order to rivet together the plates of a hull for what was then the booming Minnesota iron ore trade. Soon the large boat, christened "William P. Snyder", was shuttling hematite for the Shenango Furnace Company. "William P. Snyder" was beginning her working life at the same time as the development of the assembly line for bolting together consumer goods made with steel, such as automobiles. Iron ore boats would have plenty of work to do. "William P. Snyder" also carried iron ore to furnaces to make munitions used in World War I and World War II. Originally powered by two Scotch boilers, the vessel, by now renamed "Elton Hoyt II", was repowered in 1950 with a Skinner Unaflow steam engine and two watertube boilers. This would be the first of five separate renamings as the vessel repeatedly changed owners. Too small by the 1960s to serve as a profitable ore boat, the vessel was laid up and then, in 1966, plucked out of a freshwater boneyard for reconversion and new life as a cement carrier. Now based in Charlevoix, Michigan, the aging steamship shuttled powdered cement from Northern Michigan to a wide variety of roadbuilding contractors in various port locations on the Great Lakes. During her second half-century of life the vessel, which took on the name of "St. Marys Challenger", became a favorite of boatwatchers up and down the Great Lakes as a final example of the riveted steamships of the Second Industrial Revolution. In November 2013 "St. Marys Challenger" reached the end of her working life as a self-propelled vessel.