August Wilhelm Otto Kretschmer (1 May 1912 – 5 August 1998) was a German naval officer and submariner in World War II and the Cold War.
From September 1939 until his capture in March 1941 he sank 47 ships, including one warship, for a record total of 274,333 tons. For this he received the Knight's Cross of the Iron Cross with Oak Leaves and Swords, among other awards. He earned the nickname "Silent Otto", both for his successful use of the "silent running" capability of U-boats and for his reluctance to transmit radio messages during patrols. After the war, he served in the German Federal Navy, from which he retired in 1970 with the flag rank of Rear Admiral.
Kretschmer was born in Heidau near Neisse, then in the German Empire on 1 May 1912 to Friedrich Wilhelm Otto and Alice (née Herbig) Kretschmer. His father was a teacher at the local Volkschule (primary school), which Otto attended from 1918 to 1921. He then moved to a Realgymnasium (secondary school). In the aftermath of World War I the Kretschmer family remained aloof from the political turbulence of the Weimar era. Kretschmer indulged in sporting pastimes and scientific interests. Kretschmer achieved good results in mathematics and chemistry and passed his Abitur (school-leaving certificate) at 17. The report contained the remark, "Kretschmer demonstrated his extraordinary courage in many instances. He wants to be a naval officer." Kretschmer was too young to enlist at 17 and his father sent him to England to broaden his horizons. He enrolled at Exeter University (then University College of the South West of England) and studied under Professor Jacob Wilhelm Schopp (b. 1871), a German–born naturalised Briton. He mastered the English language and came to respect British education: its practical focus complemented his scientific and theoretical–based German background. His time in England shaped his view of them during the war. He was quick to believe in rumours of new British inventions during the war at sea. He returned home when his mother died of tetanus because of medical malpractice. He did not return to England, but travelled through France, Switzerland and Italy.
Kretschmer entered the Reichsmarine (Weimar Navy) on 1 April 1930 as See Offizier Anwärter (naval officer cadet). Kretschmer formed part of "Crew 30" (the incoming class of 1930), 78–strong intake of officer candidates. He underwent basic military training in the 2nd department of the standing ship division of the Baltic Sea in Stralsund (1 April 1930 – 30 June 1930). Kretschmer was transferred to the training ship Niobe (1 July 1930 – 9 October 1930), attaining the rank of Seekadett (cadet) on 9 October 1930 before embarking on a 14-month stay on board the cruiser Emden (10 October 1930 – 4 January 1932), which took him to the Far East through the Mediterranean and Suez Canal. The Emden made stops in Ceylon, the Philippines, China and Japan; then Guam, South Africa, Angola and Spain on the return journey. A month after the Emden's return to Wilhelmshaven on 2 December 1931, Kretschmer and his crew mates were promoted to the rank of Fähnrich zur See (midshipman) on 1 January 1932.
Following his journey on Emden, Kretschmer attended a naval infantry course for cadets at Stralsund (5 January–31 March 1932), before starting with the main cadet course at the Naval Academy Mürwik on 1 April 1932. This course was interrupted by two brief assignments on the survey vessel Meteor (22–25 June 1932 and 10–15 October 1932) for navigation training. His training included a pathfinder course for cadets at Kiel (28 March −22 April 1933), an artillery course for cadets at Kiel-Wik (23 April – 28 June 1933), a torpedo course in Mürwik (29 June – 18 August 1933), an anti-aircraft artillery course at Wilhelmshaven (19–31 August 1933), a communication course for cadets at Mürwik again (1–3 September 1933), and his first U-boat course at Mürwik (25 September – 1 October 1933).
On 2 October 1933, Kretschmer was transferred to the pocket battleship Deutschland as a gunnery officer during a trip to Denmark. This stay was interrupted for an aerial defense training course at Warnemünde (5–10 March 1934). On 19 March 1934, his stay on Deutschland ended and he was transferred to the light cruiser Köln (20 March – 26 September 1934). Kretschmer was present for gunnery exercises in the North and Baltic Sea. At Eckernförde on the 25/26 July 1934 Hitler boarded the ship to observe the exercise. During this assignment, Kretschmer was promoted to Oberfähnrich zur See (Senior Ensign) on 1 April 1934. During another torpedo training course at Flensburg-Mürwik (27 September – 21 December 1934), Kretschmer received his commission as Leutnant zur See on 1 October 1934. On 22 December 1934, Kretschmer was again on Köln serving as the ship's second torpedo officer.
In 1933 Adolf Hitler and the Nazi Party came to power. The establishment of the Wehrmacht (Nazi German Armed Forces) in 1935 divided the major branches of the armed forces. The Reichsmarine was renamed the Kriegsmarine, a Nazi creation. The OKM was established as the supreme command of the navy responsible for all facets of naval warfare. The renaming of the navy was a symbolic gesture, to erase the unpleasant memories of the 1920s and symbolise a new era. According to one historian, Kretschmer was a patriot and loyal to the government, but later "eschewed Nazi efforts to glorify his success through propaganda."
During Kretschmer's stay on Köln, he attended an aircraft catapult course at Travemünde. On 26 September 1935, he was transferred to the 1st department of the standing ship division of the North Sea in Wilhelmshaven where he served as a company officer until 25 January 1936. Kretschmer joined the U-boat service in January 1936. After the completion of his submariner training he was promoted to Oberleutnant zur See (senior-sub lieutenant/Lieutenant Junior Grade) on 1 June 1936. Kretschmer's first operational experience on a submarine was as a lieutenant on the U-35 in 1937 as first watch officer under the command of Klaus Ewerth and then Hans-Rudolf Rösing. Rösing brought his own watch officer, and Kretschmer was demoted to second watch officer. While Kretschmer was discharging his responsibilities for the operational readiness of the deck gun, Rösing dived the ship, leaving Kretschmer stranded in the freezing water. He clung to the periscope in the hope of being seen through the optics. Kretschmer was soon missed and the U-boat surfaced to find him before he succumbed to the cold.
He was given interim command of U-35 in August 1937, and this appointment coincided with Germany's involvement in the Spanish Civil War. The boat was ordered to patrol the Bay of Biscay off the Spanish-French border. The crew were permitted ashore at the resort town of San Sebastián. Rösing's successor, Hermann Michahelles, was killed in a car accident and Kretschmer assumed command for two weeks. U-35 returned to Germany after an uneventful patrol during which no ships were sunk. On 1 October 1937, Kretschmer took command of U-23. Through the remaining Interwar period, Kretschmer developed his own approach to combat, which can be summarized by the phrase "one torpedo, one ship". He dispensed with the standard practice of firing salvoes of torpedoes from long distances. Kretschmer also favoured surfaced attacks as opposed to the recommended submerged engagement, listing 11 Points of Submarine Warfare:
Efficient lookouts are of prime importance
It is essential not simply to spot the target, but to spot it in good time
Lone ships should be attacked on the surface with gunfire in order to save expensive torpedoes
Survivors should be assisted when possible
Convoys should be attacked in daylight only if it is not feasible to wait for nightfall
Attack at night from the dark side of the convoy, so that the target is silhouetted and the submarine is in shadow
When there is little or no moonlight, attack from the windward side (to avoid a visible white bow-wave when motoring into the wind)