At 21.13 hours on 9 Nov 1942 the unescorted Cerion was attacked by gunfire from U-177 south of Port Elizabeth. Due to a malfunction of the deck gun, the U-boat could only fire with the 37mm and 20mm AA guns and unsuccessfully tried to stop the ship until 23.52 hours. The ship had been missed with a spread of two torpedoes at 09.12 hours and three single torpedoes at 10.42, 20.04 and 21.00 hours, because the torpedo tracks were clearly visible and the tanker began zigzagging at full speed.

Two crewmen from Cerion were killed in the attack and the ship had to be repaired at Capetown. On 3 March, she had been bombed and damaged in the harbour of Tobruk (one crewman killed), received temporary repairs at Alexandria and was on her way to Galveston for permanent repairs when attacked by the U-boat.