Detached from Naval Overseas Transportation Service on 12 September 1919, Nereus served with the Atlantic Fleet until decommissioned at Norfolk on 30 June 1922. She was laid up there until struck from the Navy List on 5 December 1940. Sold to the Aluminium Company of Canada on 27 February 1941, Nereus operated out of Montreal carrying bauxite from the Caribbean to aluminum plants in the United States and Canada. Her master (commanding officer) was John Thomas Bennett of the Canadian Merchant Navy.
Loss
Nereus was lost at sea sometime after 10 December 1941 while steaming from St. Thomas in the Virgin Islands (along the same route where her sister ship, USS Cyclops had disappeared) with ore destined to make aluminum for Allied aircraft. Nereus was presumed sunk after being torpedoed by a GermanU-boat. However, there are no German U-boat claims for this vessel.[1] It has been suggested that both Nereus and Cyclops could have been lost to U-boats which were later lost themselves to Allied action or storms at sea. However, the record shows that in 1918 only 4 U-boats were active off the US coast[2] and in 1941 only five U-boats were lost in the Mediterranean.[3]
The wreckage has never been located, nor the actual cause of her disappearance determined.[4] A memorial listing for her crew can be found on the CWGC Halifax memorial.[5]