[1] When the First World War broke out on 1 August 1914 she was in Shanghai, China and was ordered to Tsingtao in the then German Kiaochow Bay concession.

[1] For the next seven months she operated on the high seas with Vice Admiral Maximilian von Spee's squadron off South American and then as a detached commerce raider.

Among these was the schooner William P. Frye, captured on 27 January 1915 and scuttled the next day, the first U.S. flagged vessel sunk in World War I.

[1] On 11 March 1915 Prinz Eitel Friedrich, now low on supplies and burdened by over 300 prisoners, arrived at Newport News, Virginia.

Allied warships were lying outside US waters and to avoid them she exceeded the time limit under international law for a combatant ship to remain in a neutral port.

She was reconditioned and refitted as a troop transport and renamed USS DeKalb after General Baron Johann de Kalb.

[8] On 9 February 1921 Mount Clay stood by and rescued the crew and ship's cat from the sinking freighter Bombardier about four hundred miles southeast of Halifax.

The sinking ship's radio operator, Edward Herno, had worked hours to make repairs and get the SOS out as the wireless had been severely damaged in the storm and wreck.

[9][10] Mount Clay made the initial voyage as an immigrant ship on Christmas Day 1920 (Marine Review) or 26 December (DANFS).