This loss of access coupled with the fact that the Panama Canal was not yet open, caused American-Hawaii to return in late April to its historic route of sailing around South America via the Straits of Magellan.

[13] In October 1915, landslides closed the Panama Canal and all American-Hawaiian ships, including Kentuckian, returned to the Straits of Magellan route again.

She may also have been in the group of American-Hawaiian ships chartered for service to South America, delivering coal, gasoline, and steel in exchange for coffee, nitrates, cocoa, rubber, and manganese ore.[15] At some point after the United States declared war on Germany in April 1917, the United States Army chartered Kentuckian for transporting animals to Europe in support of the American Expeditionary Force.

[16][17] Although there is no information about the specific conversion of Kentuckian, for other ships this typically meant that any passenger accommodations had to be ripped out and replaced with ramps and stalls for the horses and mules carried.

[17] On 24 April, during a convoy crossing in Army service, Naval Armed Guardsmen on Kentuckian sighted a torpedo heading towards the second ship behind her in the column.

With the signing of the Armistice on 11 November, the fighting came to an end and the task of bringing home American soldiers began almost immediately.

Though sources do not indicate the specific modifications Kentuckian underwent, typical conversions for other ships included the installation of berths for troops, and adding greatly expanded cooking and toilet facilities to handle the large numbers of men aboard.

[6][22] Her arrival on another trooping run in June returned 1,860 men,[23] including over 1,500 members of the 345th Field Artillery Regiment of the U.S. 90th Infantry Division.

[25] In all, Kentuckian made a total of five trooping runs from France, bringing back 8,895 men by the time she completed her last trip on 31 August at Norfolk, Virginia.

Though the company had abandoned its original Hawaiian sugar routes by this time,[26] Kentuckian continued inter-coastal service through the Panama Canal with a few incidents that interrupted what was a mostly uneventful twenty years.

In September 1928, a day after sailing from San Francisco, Kentuckian was rammed by the General Petroleum tanker Los Alamos near Point Sur, California, in a thick fog.

Kentuckian had a leak in her number two cargo hold and damage to her port bilge keel and returned to San Francisco for repairs.

Sailing from New York in late May, Kentuckian joined a southbound Hampton Roads, Virginia – Key West, Florida convoy.

[34] After a three-week crossing of the South Atlantic, Kentuckian arrived at Paramaribo on 22 August, where she took on a load of bauxite and made her way to New York,[35] where she docked on 20 September.

The cargo ship slowly made her way south, calling at Charleston, Key West, and Guantánamo Bay along her way to Trinidad, where she arrived on 5 November.

[39] There is no evidence that Kentuckian played any direct part in the sinking of the German submarine, but, nevertheless, members of her Naval Armed Guard were awarded a battle star for actions in the convoy from 16 to 18 April.

Over the next ten months, Kentuckian made nine more convoy crossings between the UK—where she called at Liverpool, Swansea, Milford Haven, Methil, Loch Ewe, Immingham, and Belfast Lough—and New York.