in november 2013 "st. marys challenger" reached the end of her working life as a self-propelled vessel. she steamed to the bay shipbuilding co. in sturgeon bay, wisconsin, to be cut down to an articulated lake barge pushed by a dedicated tugboat. the refitting of the former steamship lake carrier as a barge was described as a work with a cost of more than $10 million. the tug "prentiss brown" had been built in 1967 in gulfport, texas and worked in florida and new york before coming to the great lakes in 2008. the two-element vessel combination resumed the dedicated transport of powdered cement on the great lakes. in this trade, it was described in 2019 as making about 30 annual trips to the port of chicago.