Margaret was assigned to the 3rd Naval District under Naval Overseas Transportation Service and was renamed USS Chatham on 18 April 1918, probably to avoid confusion with several other U.S. Navy vessels of the same name, most notably the converted yacht Margaret (SP-527).

On the same date, the freighter arrived in the Gironde River in France at the end of her first transatlantic convoy voyage from New York carrying Army supplies for the American Expeditionary Force.

Chatham made four more such trips, delivering French steel billets and supplies for the Motor Transportation Corps to Le Havre in June for the Army of Occupation, general cargo to Rochefort in August and October, and more general cargo to Brest in December.

Upon returning to New York in late December 1918, she entered a shipyard for a complete overhaul and was soon designated for demobilization.

Reverting to the name Margaret, the ship appears to have continued to serve her original owners until she was sunk, without survivors, by the German submarine U-571 on 14 April 1942 off Cape Hatteras.