At 16.48 hours on 20 January 1942, U-552 spotted the unescorted Maro about 525 miles west of St. John’s, Newfoundland. The vessel had been in convoy ON-53, which was scattered in gale on 12 January and was straggling thereafter. Uncertain of her nationality the U-boat surfaced at 17.30 hours and ordered the ship to stop by signal lamp. However, the answer was illegible and the ship did not stop until a round from the 20mm anti-aircraft gun was fired over the bridge. Her master approached the U-boat in a lifeboat to be questioned and the Germans told him that they will sink the ship after learning that it is Greek. At 18.50 hours, the U-boat opened fire with the deck gun after the crew had left the Maro and fired 126 rounds until the ship sank in flames at 19.45 hours. The lifeboats were never seen again: the master, 26 crew members and two gunners were lost.