After sinking two ships in convoy SC-48 from within the columns on 17 Oct 1941, U-432 spotted Barfonn (Master Erling Ellingsen Vorberg) in station #53, headed towards her and fired the last loaded torpedo at 04.00 hours. The tanker was hit on starboard side in the after part of the engine room, stopped and abandoned by the master and most of the crew in three lifeboats when settling quickly by the stern. The first mate, first engineer and four men remained aboard to save the ship, but in the meantime the U-boat reloaded one of its torpedo tubes while circling the disabled vessel and fired the coup de grâce at 04.48 hours. The torpedo hit on the port side amidships under the bridge and ignited the cargo, illuminating the whole area and causing the tanker to capsize and sink with only the forecastle remaining above water. About 30 minutes later, the master, 22 crew members and one gunner (the ship was armed with one 3in and two machine guns) in the lifeboats were picked up by HMCS Wetaskiwin (K 175) (LtCdr G.S. Windeyer, RCN). Only two of the men who remained behind survived by jumping overboard and swimming to a raft. At 06.20 hours, they were picked up by HMCS Baddeck (K 147) (T/Lt A.H. Easton, RCNR) which continued to search the area until daylight, but no more survivors were found. 13 crew members and one gunner were lost. All survivors were landed at Reykjavik on 24 October.

In the afternoon, the destroyers USS Livermore (DD 429) (LtCdr V. Huber, USN), USS Plunkett (DD 431) (LtCdr W.A. Graham, USN) and USS Decatur (DD 341) (LtCdr J.C. Sowell, USN) passed the area of the night action after they were detached from convoy and spotted an object that was identified by them as upturned U-boat wreck in 56°56N/24°05W. More likely this was the capsized bow of Barfonn, which was then scuttled by the destroyers with 66 rounds of gunfire.