In late 1940 the ship together with 15 other vessels was acquired by the British government to alleviate significant shortage of tonnage due to an ongoing German U-boat campaign.

The ship was shelter-deck type, had two main decks and was built on the Isherwood principle of longitudinal framing providing extra strength to the body of the vessel.

Upon delivery to the USSB the ship loaded 8,200 tons of general cargo consisting mostly of canned and dried fruit, brandy and wine and was initially supposed to depart for France and Belgium at the end of November.

[6] After being further delayed by foggy weather, Cockaponset finally sailed out for her maiden voyage on 28 December 1919 bound for Le Havre, Rotterdam and Antwerp.

On May 28 she received a distress call from another USSB steamer, SS City of Omaha, who laid disabled about 120 miles off Cabo San Lucas with boiler problems.

[12] She returned from her trip back to New York on October 11 and remained berthed in port before being laid up at the end of 1920 and relocated to Prall's Island in January 1921.

Upon return she loaded 2,471 tons of phosphate pebble at Tampa, continued on to New Orleans to embark general cargo and left for United Kingdom in early January 1923.

On that trip she started experiencing engine problems and arrived at Gravesend with her machinery defective on 26 May 1923 and had to be towed into port to unload cargo and undergo repairs.

[17][18] After refueling, cleaning boilers and other miscellaneous repairs, the freighter departed Key West on August 30 and arrived at New Orleans a week later.

On 8 August 1924 it was reported that the Shipping Board had allocated Cockaponset to Daniel Ripley & Co., a subsidiary of Lykes Brothers acquired by them in 1923, to serve on their Galveston to French Atlantic ports as part of their Texas Star Line.

In early March 1927 Cockaponset while on her return trip to United States became disabled about 480 miles east southeast of Galveston due to engine problems.

Another Shipping Board vessel, SS West Cobalt, sped up to her aid, took the disabled freighter in tow and safely brought her into Galveston on March 10.

[22][23] After unloading and quick repairs, the ship sailed for Mobile but again became disabled due to a loss of turbine shaft on March 28 and had to be towed in.

At the end of November 1928 it was reported that Cockaponset was again allocated to Daniel Ripley & Co. and was brought in to Galveston from Mobile to undergo extensive repairs.

On 14 November 1940 the U.S. Government through the Maritime Commission offered fifteen old World War I era laid up vessels in their possession for sale to the British firms.

[31] She finally sailed with Convoy HX 126 in the early afternoon on May 10 bound for Liverpool escorted only by the British armed merchant cruiser Aurania.