At 23.03 hours on 27 Oct 1942, U-436 (Seibicke) fired a torpedo at convoy HX-212 in 54°32N/31°02W (grid AK 6725), heard a detonation after 59 seconds and observed the hit on the Frontenac. Five minutes later a spread of three torpedoes was fired and detonations were heard after 1 minute, 1 minute 16 seconds and 2 minutes 24 seconds. The third torpedo sank the Sourabaya and the fourth damaged the Gurney E. Newlin, both hits were observed by Seibicke. At 23.11 hours, U-436 fired the stern torpedo and reported another ship damaged. This is not confirmed by Allied sources.

The Gurney E. Newlin (Master Herman Leon Dahlhof) was struck by one torpedo in the engine room on the port side and immediately began to settle by the stern. Within 20 minutes the crew of eight officers, 32 crewmen and 19 armed guards (the ship was armed with one 4in, one 3in, two 20mm, two .50cal and two .30cal guns) abandoned ship in three lifeboats and two rafts. One officer and two crewmen on watch below were lost.
The master, chief engineer, third mate, chief cook, an ordinary seaman, a messman and six armed guards were picked up by the HMCS Alberni (K 103). 31 crew members and 13 armed guards were picked up within 30 minutes by the Bic Island, which was torpedoed and sunk with all hands by U-224 (Kosbadt) on 29 October.

At 09.02 hours on 28 October, the abandoned wreck of the Gurney E. Newlin was sunk by U-606 with a coup de grâce.