Erhard Maertens
Erhard Maertens or Eberhard Maertens (26 February 1891 – 5 May 1945) was a German Vizeadmiral of the Kriegsmarine during World War II. From 16 June 1941 to 5 May 1943, he was Chief of Office of Naval Intelligence, Naval War Command () in the Oberkommando der Marine. Maertens was known for underestimating British intelligence, and specifically, overrating the security of the Naval Enigma cipher machine. In 1941, he held a naval enquiry into the strength of Naval Enigma security after the capture of U-boat U-570, and attributed all the suspicious losses in U-boats at the time to the British Huff-Duff. In the second enquiry, ordered by the Commander-in-Chief of the Navy () Karl Dönitz, in May 1943, he investigated a number of areas, which exculpated Enigma security in the end, for the second time, incorrectly blaming British 9.7 centimetre centimetric radar for the massive losses in U-boats by mid 1943. Naval career On 1 April 1910, Maertens joined the Imperial German Navy as a Seekadett and had basic training on the heavy cruiser until 31 March 1911. He was promoted to an officer candidate rank () and sent to the German Imperial Naval Academy Naval Academy Mürwik for Naval training until 30 September 1912. In September 1913, he was promoted to Midshipman () after completing his training. From 1 October 1912 to 7 October 1915, Maertens was posted to the liner Hessen to learn the sailing characteristics of large ships and their movements. On 8 September, Maertens started submarine and radio training, and later posted as a watch officer on the U-boat U-3 on 17 October 1915. He completed his submarine training on 26 February 1916, promoted on 22 March 1916 to Oberleutnant zur See, and was posted to U-boat U-47 as the watch officer the day after. He was subsequently posted to U-48, to take up the same post, until 24 November 1917, when U-48 ran aground on Goodwin Sands, where the submarine was fired on by and was scuttled and abandoned. Maertens and 17 other submariners of U-48 were taken as prisoners, and held in captivity until 5 November 1919. After being released, Maertens was subordinated to the battleship for a month as a watch officer. In early 1920, he was posted to Baltiysk for two months as a Naval Signals Officer. On 1 January 1921, he was promoted to captain lieutenant, (), an officer grade of the captains military hierarchy group. On 1 March 1921, Maertens was ordered to be acting leader of the service office at Königsberg. On 7 April 1921, he was subordinated as Adjutant and Naval Signals Officer to the Commander of the naval base at Świnoujście. In October 1921, he was posted to the Coastal Defence Battalion I as company leader where he stayed until March 1925. On 1 January 1921, Maertens was promoted to captain lieutenant (). On 17 March 1925, he was subordinated to the commander of the Torpedo and Mining Academy in Kiel where he stayed until 14 August