From 15 September to 2 October 1941, Heydemann, as commander of U-575, was part of Wolfpack Brandenburg operating southeast of Greenland in the North Atlantic.

On 2 October, Heydemann sank Tuva of 4,652 gross register tons (GRT).

[1] On U-575's third war patrol which was part of the second wave of Operation Drumbeat, also referred to as the Second Happy Time, Heydemann was given a special task and did not sink any ships.

[2] On U-575's fourth war patrol which was part of the fifth wave of Operation Drumbeat, Heydemann sank Robin Hood of 6,887 GRT on 16 April 1942.

[3][4] As commander of U-575 Günther Heydmann is credited with the sinking of eight ships for a total of 48,920 gross register tons (GRT).