Thanks to albums belonging to one of the sailors aboard U-30 and then U-110, the author has been able to reconstruct the path taken by Kapit¿eutnant Fritz Lemp and his crew, including the sailor Willi Brohm, and the fate of these submarines, with texts and also pictures. We begin the story with the sailor¿s enrolment in 1936 at Cuxhaven, then aboard U-30. Then we take a look at a little-known page of history : the engagement of U-Boots in the Spanish Civil War, after 1937, with photos taken at Cadiz, Seville, Ceuta, Tetuan and the Canary Islands. It was then the beginning of the war with a good report on the U-30 under Captain Lemp. Aboard this submarine, Lemp carried off a series of successes (17 kills) which earned him the Ritterkreuz which he received on 14 August 1940, one of the first awarded to the U-Boot arm. His first engagement and success however were marred by a tragic mistake when he sank the liner Athena causing the death of civilians, including 22 Americans. He was then transferred aboard U-110 whose second patrol ended in tragedy. The submarine was attacked on 9 May 1941 in the North Atlantic. The U-boot was damaged and surfaced; most of the crew evacuated it including the sailor Willi Brohm. Captain Lemp remained aboard, probably intending to scuttle U-110, but British sailors from HMS Bulldog had time to get hold of the Enigma machine the submarine used, which had a considerable effect on the outcome of the war. Fritz Lemp disappeared with his submarine in the waters of the Atlantic. As for Willi Brohm, we follow him into captivity to Canada, with very rare and exceptional photos. A fantastic, historic album gathering together more than 200 photos and documents of which 160 photos from our own archives ; various documents are unpublished. Text in French.