The third USS Saranac was the Old Dominion Steamship Company Hamilton temporarily converted for planting the World War I North Sea Mine Barrage. John Roach & Sons launched Hamilton at Chester, Pennsylvania in 1899. Hamilton steamed between Norfolk, Virginia and New York City until The United States Shipping Board took control of the ship from Old Dominion Steamship Company in 1917. She was fitted out for United States Navy service by James Shewan & Sons at Brooklyn, New York. The minelaying conversion enabled her to carry mines on two decks, and included four Otis elevators individually capable of transferring two mines every 20 seconds from the storage deck to the launching deck. USS Saranac was commissioned on 9 April 1918. While operating as part of Mine Squadron 1 out of Inverness, Scotland, from 14 July until the close of the war on 11 November 1918, Saranac laid a total of 4,782 mines:
Saranac then returned to the United States for decommissioning and return to Old Dominion Steamship Company in 1919.
In the words of British Rear Admiral Lewis Clinton-Baker, the North Sea mine barrage was the "biggest mine planting stunt in the world's history." The United States converted eight civilian steamships as minelayers for the 100,000 mines manufactured for the barrage. Old Dominion Steamship Jefferson was similarly converted to USS among these eight.