Completed as Mehanno in December 1919 for US Shipping Board. On 14 Nov 1941, acquired by the US Navy and converted to the stores ship USS Yukon (AF 9). Served in the Pacific Fleet until decommissioned and laid up at Philadelphia in April 1922. In January 1940, the ship was recommissioned and served in the Atlantic Fleet.

On 23 Jan 1942, the USS Yukon (AF 9) experienced engine troubles while en route from Iceland to the US East coast and was disabled. The next day, she was taken in tow for Reykjavik by USS Alexander Hamilton (WPG 34), which was relieved on 29 January by the HMS Frisky (W 11). At 16.10 hours, U-132 (Vogelsang) fired a spread of four torpedoes at the small convoy off Reykjavik and sank the US Coast Guard cutter, while the stores ship was missed by a torpedo by about 250 yards and reached the harbour safely.

On 18 Mar 1946, the USS Yukon (AF 9) was decommissioned at Norfolk, transferred to the US Maritime Commission and sold for scrap to Boston Metals, Baltimore in July 1946.

At 18.54 hours on 22 Sep 1944, USS Yukon (AF 9) (Cmdr McMullan), escorted by USS Babbitt (DD 128), was hit on the starboard side in the bow by one of two torpedoes from U-979 about four miles from Skagi Lighthouse, Reykjavik. At 19.04 hours, the U-boat fired a Gnat as coup de grâce, but it missed. One crew member was lost, another died of wounds and 13 others were wounded. Assisted by two tugs, the ship arrived at Reykjavik after five hours and was unloaded to examine the damage. The explosion had opened a 60 foot hole from the stem aft, blew out the #1 double-bottom tanks and caused two cracks amidships.

On 14 November, USS Yukon (AF 9) left Reykjavik after temporary repairs for Norfolk, escorted by USS O´Toole (DE 527) and USS Abnaki (ATF 96). Due to a severe storm after nine days, she had to put into Argentia, Newfoundland and arrived in Norfolk on 5 December, was repaired at the Naval Yard and returned to service on 5 Feb 1945.