At 01.00 hours on 27 Aug 1942 the unescorted Clan Macwhirter (Master Roderick Sutherland Masters), a straggler from station #11 in convoy SL-119 due to engine troubles since 20 August, was hit on the port side by two torpedoes from U-156 about 190 miles north-northwest of Madeira. The first struck in the after end of #2 hold and the second between #4 and #5 bulkhead, blowing off the hatch covers and causing the ship to settle fast with a heavy list to port. She sank by the stern after about 10 minutes while the crew was still abandoning ship, but three of the six lifeboats could be launched. The master, nine crew members and two gunners (the ship was armed with one 4in and five machine guns) were lost. The U-boat surfaced, questioned the survivors and gave them the course and distance to the nearest land before leaving the area.

The lifeboats remained at the sinking position until daylight, picking up the men swimming in the water and clinging to wreckage or rafts. Then they set sail to Madeira together until being separated in a gale on 28 August. When the boats closed the island on 30 August, the second mate sent a radio message with an emergency transmitter. This was heard by the Portuguese authorities who sent the sloop Pedro Nunes (A 528) to search for them. All three boats were located during the next days and all 67 crew members and seven gunners landed at Funchal until 2 September. The survivors were taken to Lisbon after five weeks from where they were repatriated via Gibraltar.