On 27 Apr, 1945, U-1105 detected three British frigates about 25 miles west of Mayo, which were part of the 2nd Division of the 21st Escort Group. The U-boat fired two Gnats and dived to 100 meters to escape the counterattack but was unable to hold the depth and sank to the bottom at 174 meters, remaining motionless. The first torpedo hit HMS Redmill (K 554) (Lt J.R.A. Denne, RN) after 50 seconds, followed by the second just seconds later. The ship was badly damaged but remained afloat, assisted by HMS Rupert (K 561) (Lt P.C.S. Black, RN). The U-boat was unsuccessfully searched in the next 31 hours by several ships and planes. On 4 May, the Germans surrendered ironically to the 21st Escort Group, which had not been able to find her the week before.

HMS Redmill (K 554) lost about 60 feet from her stern, was towed to Lisahally and declared a total loss. On 20 Jan, 1947, the hulk was returned to the US Navy and on 4 February sold for scrap to Athens Piraeus Electricity Co Ltd, Athens.