Between 15 July 1944 and 7 November, "Flaherty" completed two more hunter-killer patrols with the Guadalcanal group, then served as school ship for the Naval Training Center at Miami, Florida. Training in the Caribbean with carriers followed, until she sailed from Naval Station Mayport, 9 April for Argentia, Newfoundland. This was her base for duty on the barrier line established in the last months of the European phase of the war to prevent desperate U-boats from penetrating the western Atlantic. On 24 April, was torpedoed while investigating a submarine contact, and Flaherty dashed to rescue her survivors. After three men had been taken on board, "Flaherty" picked the submarine up by sonar, and moved in to attack. Seven other escorts joined her in the 10-hour hunt, which resulted in forcing to the surface, where she was sunk by gunfire. She recovered five of the U-boat's survivors, including the commanding officer.