At 22.20 hours on 2 Nov 1944 the unescorted Fort Thompson (Master Lester Saul) was hit on the starboard side in #1 hold by one torpedo from U-1223 while steaming on a zigzag course at 11 knots about 7.5 miles northwest of Matane, PQ. The ship was immediately swung to starboard to get in shallow water, while the lifeboats were readied to be lowered and manned. However, the port aft boat freed itself when lowered too far and drifted off with 17 occupants. They were ordered to steer south in charge of Cadet Crawford and eventually made landfall near Matane. The master, 36 crew members and the ten DEMS gunners (the ship was armed with two 12pdr, one 40mm and six 20mm guns) remained aboard, sent distress signals and anchored the ship in about 10 fathoms of water to investigate the damage at about 23.10 hours. The #1 hold and tank were flooded and the bilges in #2 hold were making water, but after the river water in the forepeak was pumped out the water level did not raise further. In view of the fine weather the next day, it was decided to return to port under own power with the help of the Canadian tug Lord Strathcona, arriving in Quebec around noon on 4 November.

After temporary repairs, the Fort Thompson sailed to St. John, New Brunswick from 11 to 18 Dec 1944. She was repaired and returned to service in March 1945.