Herbert Wohlfarth began his naval career in April 1933. After the usual training that he spent more than a year on the
cruiser . In May 1937, he joined the U-boat force, and like many of the later successful commanders received a solid pre-war training under
Karl Dönitz. After some months as aide-de-camp in the
3rd U-boat Flotilla, in September 1938, he became watch officer on . On 19 October 1939
Oberleutnant zur See Wohlfarth took command of . On his first three patrols he sank nine mostly smaller ships in
Scottish and
Norwegian waters. The fourth patrol with
U-14 was for him, as for most other commanders during
Operation Hartmut, supporting the
invasion of Norway, without success. On 15 June 1940 Wohlfarth commissioned , also a
Type IID U-boat, referred to as
Einbaum (dugout canoe). But these small boats were also very successful and other well-known commanders including
Hardegen,
Kretschmer and
Lüth won their first successes in them. Wohlfarth led
U-137 on three patrols during the autumn of 1940. He sank six ships for a total of , mostly in the area south of the
Hebrides. Especially notable was his
torpedo hit on the 10,552-ton
armed merchant cruiser , damaging the ship so badly that she had to spend six months in the shipyard for repairs. On 15 May 1941 he received the
Knight's Cross while still on patrol. On 26 May, during the return voyage, and ten days before his 26th birthday, Wohlfahrt responded to a call for all
U-boats in the
Bay of Biscay to support the 's increasingly deteriorating position. The
aircraft carrier , battlecruiser and battleship had a lucky escape during the night, unaware they had come within firing range of Wohlfarth's
U-556, which had already fired off all its torpedoes. This was particularly galling for Wohlfahrt, as
U-556 and
Bismarck had exercised together in the Baltic, and as Wohlfarth had jokingly created a Certificate of Sponsorship, promising to protect the
Bismarck.
U-556 continued to shadow the British forces, reporting their position and guiding other U-boats to the area. Wohlfarth witnessed the night battles between
Bismarck and British destroyers. ==Prisoner of war==