At 13.15 hours on 20 June 1940, U-61 (Oesten) observed how the unescorted and zigzagging Empire Conveyor (Master Finlay Black MacIntyre) was hit on the port side forward by a torpedo about 50 miles south of Barra Head, Hebrides. The attacker must have been U-122, which was lost shortly afterwards but reported sinking a large freighter in a radio message at 00.30 hours on 21 June.

The Empire Conveyor did not sink immediately, but because the aerials had been damaged the radio operator was unable to call for help. Luckily a flying boat on patrol in the area arrived, dropped bombs to keep the U-boat down and alerted the Admiralty. The tug HMS Amsterdam was sent out, escorted by HMS Atherstone (L 05) (Cdr H.W.S. Browning, RN) and HMS Campbell (D 60) (LtCdr R.M. Aubrey, RN), but at 16.00 hours she suddenly sank before the ships arrived. The crew had abandoned ship in three lifeboats and several rafts, but one boat swamped during launch. The master, the second engineer and the cook were lost. 38 crew members were picked up by HMS Campbell (D 60) after six hours and landed at Liverpool the next day.