Having discharged her cargo, West Lashaway loaded a return cargo—which included 300 tons of Army ordnance materials—and sailed for New York City on 20 March.

From 1919 through the mid-1920s West Lashaway was active in transatlantic service, carrying cargo between New York and various European ports such as Lisbon, Portugal; La Pallice, France; Valencia, Spain and Genoa, Naples, Palermo, Trieste and Fiume, Italy.

[8] In 1935, U.S. customs agents uncovered and seized a stash of 1,000 bottles of contraband Scotch whisky on board the ship upon her return from the Cape Verde Islands.

[9] West Lashaway again made headlines in July 1937 when a crew member was handed to port authorities in chains after allegedly attempting to set fire to the vessel on the open sea and murder the captain.

[11] In 1939, the ship's crew was involved in a strike that won American merchant mariners a 25% wartime wage increase for "sailing in dangerous waters".

[14] After the United States entered World War II in December 1941, West Lashaway continued to operate in the Africa trade.

On the night of 30 August 1942, while returning to the United States from Matadi, Congo with nine civilian passengers and a cargo of 7,670 tons of tin, copper, cocoa beans and palm oil, West Lashaway was struck on the starboard side at around 2:30 pm by two torpedoes fired from U-66.

[15][16] Shortly after the sinking, U-66 surfaced and briefly opened fire with small arms, but soon departed, leaving a total of 42 survivors on four rafts from the ship's original complement of 56.

After nineteen days on the open sea, they were rescued by the destroyer HMS Vimy (D33), but not before the rescuers had fired 16 rounds at the raft in the mistaken impression it was a German submarine.

25 days after the sinking of West Lashaway, the raft which had been cut loose washed up on the island of St. Vincent, with the body of Gunner's Mate 3/C Dalton Munn, and the sole survivor of this group, boatswain Elliott Gurnee.