 The boat's third sortie commenced with her departure from St. Nazaire on 10 December 1941.This was not only the shortest patrol of her career but the only time she returned to France, (this time to La Pallice where she would be based for the rest of her time), without success, on the 23rd.Her fourth patrol was carried out on the eastern seaboard of Canada and the United States, where she sank a number of ships, including the-then neutral Brazilian vessels "Buarque" and the "Olinda" on 15 and 18 February 1942 respectively.