Career
The Knight"s Cross of the Iron Cross was awarded to recognise extreme battlefield bravery or successful military leadership. World World War II Mengersen commanded the U-18, U-143, U-101 and U-607, and sank twelve ships, including the Steamship Gairsoppa and HMS Broadwater, on eleven patrols, for a total of 68,071 gross register tons (GRT) of Allied shipping. The Gairsoppa carried 7,000,000 ounces of silver, which was worth £600,000 at the time of its sinking.
Egon-Reiner von Schlippenbach served as first watch officer on U-101"s fourth patrol under Mengerson, while Karl-Heinz Marbach was Mengerson"s second watch officer on U-101.
In June 1943 Mengersen became commander of the 20th U-boat Flotilla based in Pillau, remaining in this position until 24 February 1945. During the last three months of the war, Mengersen served firstly with the 25th U-boat Flotilla and then in April 1945, he was selected to command the new 15th U-boat Flotilla.
Reference in the Wehrmachtbericht Mengersen survived the war and died in Detmold, at the age of 83.