At 00.58 hours on 15 September 1942 the unescorted Breedijk (Master Bernardus Ludovicus Josephus Ruÿgrok) was hit on the starboard side in #5 hold by one G7e torpedo from U-68 while steaming on a non-evasive course at 11.5 knots in a dark night and calm sea about 370 miles east-northeast of Ascension Island. The U-boat had spotted the ship about 5 hours earlier but it was in Zone A, an area previously reserved for blockade runners and merchant raiders, so Merten queried the BdU if it could be a friendly vessel and waited with the attack until he got the answer: Angriff frei (attack allowed). The torpedo hit started a small fire in the superstructure aft which soon went out when Breedijk settled by the stern and sank after 15 minutes. The master and one crew member were lost. 45 crew members and five gunners (the ship was armed with one 4in and six machine guns) had abandoned ship in four lifeboats and Merten questioned the survivors, talking in German with them and got no answer when he asked for the master, chief engineer or radio officer to take them prisoner.

On 18 September, the 13 occupants in the boat in charge of the chief officer were picked up by the British ocean boarding vessel HMS Corinthian (F 104) (Cdr E.J.R. Pollitt, RNR) which then continued her search for survivors from Laconia and eventually landed them in Freetown nine days later. The 13 survivors in another lifeboat were rescued by the Portuguese steam merchant Cubango on 21 September and taken to Lisbon, arriving on 5 October. HMS Decoy (H 75) (LtCdr G.I.M. Balfour, RN) picked up the 13 survivors from the boat of the third officer and brought them to Freetown two days after their rescue on 23 September. The fourth lifeboat with twelve crew members and one gunner reached the Ivory Coast in early October and the Vichy French authorities interned the survivors in Abidjan, where they were treated harshly before being released and repatriated via Takoradi in December 1942.