She was commissioned into the Naval Overseas Transportation Service (NOTS) of the United States Navy as USS West Cohas (ID-3253) in June 1918.

West Cohas ran aground off Sable Island in 1925 while trying to assist a vessel in distress, but otherwise had a relatively uneventful merchant career for the USSB.

After splitting the rest of the war between voyages to North America and Africa, Empire Simba was loaded with chemical weapons in August 1945 and scuttled west of Ireland.

[3] The ship had a double reduction-geared steam turbine that drove her single screw propeller, giving her a speed of 10.5 knots (19.4 km/h).

After successfully completing sea trials, West Cohas sailed for Arica, Chile, to carry a cargo of nitrates to the United States.

Sailing from Arica on 29 July, West Cohas transited the Panama Canal and arrived at Charleston, South Carolina, where she unloaded the cargo.

On 20 July, The Washington Post carried a news report that West Cohas had run aground on shoals off Sable Island.

The French fishing trawler Labrador had run aground on the shoals on the morning of 19 July and had issued a distress call.

[14] There were no follow up reports to indicate how much damage West Cohas sustained, but she escaped the fate of the 399 GRT Labrador, which was a total loss.

In July 1938, she was sailing from New Orleans to Liverpool when she rammed the Irish motor vessel Munster 15 nautical miles (28 km) north of Dublin.

[19] The ship was transferred to the Ministry of War Transport, which renamed her Empire Simba and assigned Andrew Weir & Co. of London to manage her.

[16] After spending six weeks at Methil, where she had an advanced ship degaussing system installed among other repairs,[20] Empire Simba proceeded to Oban via Lyness in mid November.

[20][22] After two weeks in Baltimore, Empire Simba headed to Hampton Roads, Virginia, to take on another load of scrap iron for the UK.

[24] Off the Northern Ireland coast, the convoy escorts broke off and Empire Simba and three other ships sailed into the Irish Sea.

At 1300 hrs on 1 March,[20] a Heinkel He 111 bomber of Kampfgeschwader 27, Luftwaffe attacked the column,[25] and had a near miss on Empire Simba.

The German bomber, with smoke trailing from it after being hit by bullets from one of Empire Simba's two Hotchkiss Mark I machine guns, headed off for Ireland.

[30] On 11 September Empire Simba was scuttled in the North Atlantic beyond the continental shelf, 120 nautical miles (140 mi; 220 km) northwest of Ireland.

[31] Empire Simba was one of four redundant cargo ships that the Admiralty used to dispose of chemical ammunition at the same site in the North Atlantic in 1945.