Assigned the naval registry identification number 3439, she was commissioned on 30 September 1918 as USS Ozaukee (ID-3439) at San Pedro, California.

At Arica, Chile, she took on nitrates and steamed via the Panama Canal to Jacksonville, Florida, where she arrived on 7 December 1918.

At the end of January 1919, Ozaukee departed Philadelphia to cross the Atlantic Ocean to deliver oil and tobacco to London in the United Kingdom.

When she was about 700 nautical miles (1,296 kilometers) east of Philadelphia her steering gear carried away in heavy weather.

Her crew rigged temporary steering gear and she completed the trip, arriving at London in mid-February 1919.