Between 01.50 and 01.59 hours on 5 August 1941, U-372 fired four single torpedoes at ships in convoy SL-81 west of Ireland. First the stern torpedo struck the Belgravian, which burned out and sank the next day. Neumann reported that the second torpedo missed the intended target but exploded on a ship beyond, the third torpedo was a dud and the fourth hit an ammunition freighter, which exploded and sank by the bow in 50 seconds. The ship missed was the British steam merchant Volturno, but a hit on another ship is not confirmed. The ship sunk was the Swiftpool.

The master, 35 crew members and five gunners from the Swiftpool (Master Harry Raymond Clark) were lost. Three crew members were picked up by HMS Bluebell (K 80) (LtCdr R.E. Sherwood, RNR), but one of them died of exposure and was buried at sea the next day. The survivors were landed at Greenock.