After the United States' entry into World War I, a large shipbuilding program was undertaken in the country both to restore and enhance the nation's shipping capabilities and those of its allies.

[6] Following delivery to USSB the ship was immediately handed over to Pacific Mail Steamship Company to operate on the West Coast of the United States to the Orient route.

On her westward trips the ship carried mostly lumber, but also grain, flour, herring and metal products while on her return journeys she would transport sugar, copra, hemp, mahogany, peanuts, various vegetable oils and other oriental merchandise.

For example, in early January 1921 the freighter took on board 1,750,000 feet of lumber from Dollar Mills in Vancouver and 250 tons of general cargo before sailing for East Asia.

In early January 1924 when Admiral Line's steamer SS Harold Dollar steering gear got jammed by a shifted deckload of lumber, Wheatland Montana rushed to aid and stood by until the problem was resolved and the freighter could safely proceed to her destination.

[11] On 1 April 1926 while on her way from Qingdao to Puget Sound ports with a large cargo of hemp, peanuts and mahogany logs, Wheatland Montana lost her propeller and rudder post, and was drifting helplessly in stormy weather.

[12][13] After about two weeks of towing and about 700 miles from the Puget Sound, West Niger was relieved by yet another Admiral Oriental Line steamer, SS City of Spokane who brought the disabled freighter safely to port on April 24.

Approximately 700 miles from the Puget Sound West Nomentum was forced to pause due to her fuel running low, and both ships had to await the arrival of the US Coast Guard cutter Algonquin which safely brought the disabled steamer into port.

Tacoma Steamship Company continued to operate as an independent entity through 1937 between the same ports in the United States and Canadian Northwest and respective destinations in China, Japan and the Philippines.

[24][25] In the fall 1932 Seattle and the rest of Tacoma-based vessels were put on the twin-shuttle route taking them to California ports of Los Angeles and San Francisco in addition to their regularly served destinations.

[28] In April 1936 due to increase in traffic Seattle was used by Dollar for one trip to transport a large cargo of cotton, scrap tin, used rails and other general merchandise from California to Japan.

[34] After loading a cargo consisting of 7,385 tons of sugar and canned pineapples, the ship departed Hawaii on April 10 for East Coast ports of New York, Philadelphia and Baltimore, passed through the Panama Canal on May 5 and reached her destination on May 20.

[35] On her return voyage the freighter departed Baltimore on May 31 loaded with 5,180 tons of cargo consisting of steel and general merchandise, and reached Honolulu on July 3.

The freighter was occasionally used on other routes, for example, she sailed from the Pacific Northwest ports to Liverpool in November 1937 carrying 8,024 tons of cargo consisting of wheat, lumber and fish.

Upon loading her cargo the ship sailed from New York in mid-February 1942 bound for Trinidad where the freighter was scheduled to bunker before proceeding to her next stop at Cape Town.