The Type XIV milch cow (U-tanker) U-489 departed Kiel on her maiden voyage on July 22, 1943, her destination was probably the North Atlantic (although the survivors reportedly told the British they were first ordered to Japan, but that order had been changed to Madagascar). Her roll was to supply other submarines with oil, ammunition and other stores. She was a new boat, commissioned on Mar. 8 of the same year. For Oberleutnant Adalbert Schmandt, U-489 was his one and only command. U-489 was in company with U-647, which was also on her maiden voyage, when on July 29 a radio signal was sent to the two boats alerting them to a downed aircraft. The three man crew of the Blohm & Voss aircraft, which had been shot down by a Beaufighter of 404 Squadron RAF, was located by Schmandt and picked up. Rather than turn around Schmandt proceeded out to sea, this was the only success Schmandt and U-489 ever had, for the remaining voyage was a disaster.

Shortly after recovering the air crew, U-647 went missing, probably mined, but U-489 continued to head to the open sea. On Aug. 3 the boat was located by a Hudson of 269 Squadron RAF which dropped two bombs, one of which damaged the boat causing a leak into the aft battery compartment. Two more aircraft, a Catalina of 190 Squadron RAF and an unidentified U.S. B-17 soon arrived, the B-17 failed to attack, but the Catalina made an attempt. The Catalina was taken under fire and damaged, and therefore did not attack the boat, the pilot turned away and made for base. U-489 went deep to avoid what they believed were concentrated attacks, but the leaks into the battery caused Schmandt to come back to the surface for repairs. When he surfaced he sent a signal to U-boat headquarters, which brought at least two Royal Navy destroyers into the area.

The leak was repaired, but she was soon under attack by the destroyers. Dropping depth charges, none of which seriously damaged the boat, the Royal Navy would not let go of their target. They were down for so long that the batteries were depleted, Schmandt had little choice but to surface and run for it. A little after 0900 on August 4, 1943 U-489 was sighted by the crew of Sunderland "G" of 423 Squadron RCAF some five miles distant. The pilot, Flying Officer Albert A. Bishop, RCAF commenced an immediate attack. As he approached the boat he came under heavy fire which badly damaged his aircraft, however he continued the attack and dropped six depth charges, which exploded close to the boat.

Bishop's aircraft was on fire and he soon had to put down into the sea, the landing was not smooth and the plane went end over before coming to a stop. Bishop got out and aided a fellow crewman who was badly injured, he kept the man afloat for an hour or more until they were picked up. Five of the airmen sadly were lost in the crash. F/O Bishop was awarded the D.F.C. for his actions in sinking the U-489 and saving a fellow crewman.

While this drama was playing out U-489 was in a serious situation, damage caused by the depth charges and the fast approaching destroyers was enough for Schmandt to know his boat was lost. He ordered the crew off and the boat to be scuttled. Fifty-six men, including the three Luftwaffe crew, got off the boat and into liferafts, but as the boat was going down an explosion, possibly from a scuttling charge, ripped through the boat seriously injuring the chief engineer, he later died in HMS Castleton of his injuries. All of the remaining men survived and were interned until after the war.