In November 1942, while operating with Convoy SC-107, Empire Leopard was torpedoed and sunk by U-402, commanded by U-boat ace Siegfried von Forstner.

[3] Laden with general Army supplies, West Haven departed New Orleans on 3 July and steamed to Norfolk, Virginia, where she joined a convoy sailing for Europe.

[3] Following a brief layover in New York, West Haven loaded 7,075 tons of general Army cargo at Baltimore and sailed on 5 December, bound for France.

[3] After topping up her bunkers, West Haven arrived at Norfolk on 4 March to load 673 tons of cargo for her fourth and final voyage for NOTS.

In February 1929, West Haven was sold by the USSB to the Los Angeles Steamship Company (LASSCO), who at this time were in the process of expanding their line from four ships to ten.

After battling gales for three weeks in the North Atlantic, West Hardaway had run out of fuel and was drifting helpless when Marian Otis Chandler arrived on the scene to tow the vessel 500 miles to Halifax, Nova Scotia.

[14] In June 1930, Marian Otis Chandler was placed into service between Los Angeles and Hawaii after the LASSCO liner City of Honolulu was badly damaged in a fire.

[3][6][18] In 1940, Onomea was acquired by the British Ministry of War Transport (MoWT) in order to help alleviate the shipping shortage caused by losses to German U-boats.

Between February 1941 and August 1942, Empire Leopard completed five round trips across the Atlantic, carrying vital supplies of steel, sulphur and other goods from the United States to the British industrial cities of Liverpool and Hull.

Returning to Hampton Roads, Virginia in July, Empire Leopard loaded a cargo of sulphur and completed her second round trip to Britain with Convoy SC-50, arriving at Hull on 8 November.

[19] Empire Leopard's third round trip was completed from New York with Convoy SC-67 in February 1942, this time with a cargo of general goods bound for the Tyne, England.

Empire Leopard's fifth and final successful round trip between Britain and the United States was completed from Cape Cod, Massachusetts to Hull in August 1942, sailing in Convoy SC-95 with a cargo of steel and general goods.

[19] Following the discharge of her cargoes at Hull, Empire Leopard made her final voyage to North America via Methil and Loch Ewe, Scotland to Botwood, Newfoundland via St. John's in September–October 1942.

At St. John's, Empire Leopard joined another 44 merchant ships and a small number of escorts preparing to sail for Liverpool as Convoy SC-107.