Zeus was built in 1964, is 98 feet long and flies the US flag

The tug Zeus comes to Duluth with the barge Robert F. Deegan.  They usually bring a cargo of calcium chloride that was pumped from salt mines near Ludington, Michigan. The source of the calcium chloride is essentially a well near or in the salt mine. It is a high grade liquid (42% salt content) that needs to be diluted a bit here before it is sent to the end customer, mostly county highway departments in Minnesota. They use it to keep the dust down on road construction and other maintenance projects.
The Robert F. Deegan  was built in 1968 in Houston, Texas by the Wyatt Division of US Industries. It is currently owned by Dann Marine Towing in Chesapeake, Maryland. It measures 225.8 feet x 60 feet. The picture above was taken by James Madden on June 29, 2017 just after she came in through the Superior entry.