German Navy Intelligence Service

The German Naval Intelligence Service (German: Marinenachrichtendienst) (MND) was the naval intelligence department of the Germany Navy and had a long history, going back to naval aspirations of German Emperor, Wilhelm II in 1899.

The department had various names throughout its existence. Between 1901 and 1919, the service was called the Nachrichten-Abteilung also known as N (English:News Department) and was the naval intelligence service of the Imperial German Navy. It focused its efforts on France, the United States and above all the United Kingdom, whose Royal Navy was Germany's principal rival for naval supremacy. Its activities had little practical impact on the course of the First World War and it was dissolved in 1919 after Germany's defeat in the war. After the war, saw the establishment of the observation service (B-Dienst) in 1918-1919. In spring 1925, the Naval Intelligence Division was disbanded and didn't reform until October 1934 under Theodor Arps when it was named Marinenachrichtendienst (English: Naval Intelligence Service). During the Second World War, the service underwent various re-organizations, starting as part of 2/SKL, later 4/SKL of the Oberkommando der Marine (OKM) and finally dissolved in July 22, 1945, 2 months later than the end of hostilities.

Establishment
After the Admiralstab was established in 1899, its chief, Vice-Admiral Otto von Diederichs, sought to establish a naval intelligence department. He petitioned Kaiser Wilhelm II in January 1900 to approve the project. Although the Kaiser approved, Diederichs' plans were blocked by Admiral Alfred von Tirpitz of the German Imperial Naval Office, with whom he had previously clashed over plans to expand the authority of the Admiralstab. Tirpitz simply declined to answer Diederichs' request for funds, prompting the latter to approach the Kaiser again in January 1901.

Diederichs presented a memorandum arguing that without an intelligence staff, it would be impossible for the navy to develop contingency plans for war. It needed to focus on Germany's most likely naval enemies – France, the United Kingdom and the United States – but currently had only limited means for gathering intelligence, including reviewing newspaper reports and utilising naval attachés as a source of information. The navy neeeded to have its own dedicated intelligence staff, modelled on the German Army's Abteilung IIIb. Diederichs asked for four staff to man the new department; one staff officer to serve as its head, with one lieutenant commander as assistant; one more officer off active duty to carry out confidential work such as couriering correspondence and paying agents; and a cartographer who could double as a photographer. It would need an annual budget of 150,000 marks a year.

The Kaiser again approved the proposal and directed the Naval Office to implement it, but Tirpitz continued to obstruct Diederichs – this time by reducing his budget from the requested 150,000 marks to only 10,000. Nonetheless this was enough to establish the new department at the Admiralstab's headquarters at 70 Königgrätzer Straße (today's Stresemannstraße) in Berlin. Originally called the Nachrichtenbüro ("Intelligence Bureau"), it was soon renamed the Nachrichten-Abteilung or "Intelligence Department", known simply as N for short.

1901 to 1918
The Navy news service (German:Nachrichten-Abteilung) was an educational and news analysis service of the Imperial German Navy (German:Kaiserliche Marine) or Admiralstab between 1901–1919. From 1901 is was known as the news bureau (German:Chiffrierbüro (Ch)) and Intelligence Bureau (N) and was considered separate in function and form from the news service of the German Imperial Naval Office, whose function was considered a press or propaganda office of the Navy.

Organization
Before the First World War, the organization of the Naval Intelligence Service was as follows: In the Naval Staff, there was a single naval officer, who was responsible for all questions and problems of the intelligence service. The department soon grew in size to four members, despite Tirpitz's continued obstructions. It had three heads during its 18 years in existence. The head of the news department of the Naval Staff of the Navy were:
 * Captain Alfred Tapken --- 1901 to March 1914. Later Commander. Married to an Englishwomen.
 * Commander Walter Isendahl --- March 1914 to February 1918. Frigate Captain.
 * Captain Paul Ebert --- February 1918 – 1919

The director of N customarily signed documents with a capital 'N' and the first letter of his own name.

Within N, duties were divided between several subdivisions. The most important was the overseas intelligence gathering division, NI, which was managed from 1913 to 1919 by Commander (later Naval Captain) Fritz Prieger. Secretarial responsibilities were managed by Naval Lieutenant Georg Stammer, who handled correspondence for N and NI and also worked for naval counter-espionage. More branches were added during the First World War, when N grew hugely in size. Although its numbers are not recorded in the surviving German archives of the period, it certainly employed hundreds of staff at the very least; its army counterpart employed over 1,100 people at its peak in 1918. One of those employed by N in a minor position was Wilhelm Canaris, who rose to become head of the Abwehr, the Third Reich's military intelligence service. A naval counter-espionage agency called G (for Gegenespionage or counter-espionage) was spun off from N, under the authority of Paul Ebert, who was to become the News service director in 1918. A sabotage branch called NIV was established within N in the spring of 1916, operating under the cover of a commercial agency.

The news service operated in a significantly different fashion from its great rival, the British Secret Service Bureau (which later divided to become MI5 and MI6). It was directly integrated into the Admiralstab and recruited exclusively from the Imperial Navy, in contrast to its more independent and less military-oriented British counterpart. Rather than pursuing careers in the organisation, its staff would serve stints of a few years in N before rotating back out into mainstream naval careers. After Tapken left N in 1914, for instance, he continued working for the Admiralstab in various capacities and was promoted to rear-admiral during the war.

The service operated in a significantly different fashion from its great rival, the British Secret Service Bureau (which later divided to become MI5 and MI6). It was directly integrated into the Admiralstab and recruited exclusively from the Imperial Navy, in contrast to its more independent and less military-oriented British counterpart. Rather than pursuing careers in the organisation, its staff would serve stints of a few years in N before rotating back out into mainstream naval careers. After Tapken left N in 1914, for instance, he continued working for the Admiralstab in various capacities and was promoted to rear-admiral during the war.

Recruitment
The primary target of the News Service was the British Royal Navy, the largest and most powerful navy of the time. From its establishment in 1901 it sought to recruit a network of agents around the world to observe the movement of foreign warships, which in practice meant principally British ships. Political considerations led the service to also focus attention on the French Navy. The organization recruited two types of agents: fleet observers, rapporteur (German:Berichterstatter)or (BE's) and confidential men (German:Vertrauensmänner) or (VM's). BE's were originally intended to gather intelligence on foreign naval movements while VMs were to help supply German warships in wartime. The commanders of individual German battleships were responsible for recruiting agents in each of their ports of call. To protect agent networks, all communications with BE's were routed exclusively through "main correspondents" (German:'Hauptberichterstatter) or HBE's who were responsible for providing them with codes, wireless telegraphs and other secret communications equipment during periods of international tension or war.

Recruiting agents was not straightforward for N. It sought to recruit reserve German army officers working abroad, but this resulted in complaints from the army and only produced a few recruits (though this exercise did make it possible for N to recruit more agents during the war). Its army intelligence counterpart, Abteilung IIIb, was of little help; the two agencies viewed each other as rivals and were reluctant to share information or assets. The various German steamship companies, especially the Hamburg America Line (HAL), provided a valuable source of recruits. Shipping employees were regarded as ideal candidates for recruitment; they were widely traveled, often expert in naval matters and were stationed across the world. Their companies were happy to cooperate as they looked forward to receiving valuable naval contracts, while the employees themselves would enjoy exemption from conscription so that they could continue to work as naval intelligence agents. The German agent Carl Hans Lody, who spied in the UK in the early months of the First World War, was one such example of a shipping employee who had been recruited as an operative.

The German diplomatic service was also an important source of recruits, with the Admiralstab approaching German diplomats to recruit them directly or to enlist their help in recruiting others. The German foreign ministry had reservations about this activity, as it feared the consequences for its reputation if it became known that its diplomats were working for the navy, but by 1911 it had thrown its support behind the navy's efforts to recruit agents.

It was then alleged that during the early 20th century, the unit placed a troupe of fleet observers along the Russian Baltic coast built. The unit used its own agent networks, especially against the Russian Empire. To that end, the service had set up a number of bases in the Scandinavian countries. From 1912 it cooperated with the Swedish naval service to enable military reconnaissance. During 1914-1915 of the First World War, the service participated decisively in the use of the East Asia Squadron, later on the revolutionizing of Russia and Finland. [8] When the war ended, the news department of the Naval Staff, unfortunately destroyed large parts of their records inventory, a fact which today is very difficult verification of allegations contained in this paragraph.

Day to Day Operations
On the eve of the First World War, N had established a global "war intelligence system" (Kriegsnachrichtenwesen or KNW) which was intended to provide a flow of intelligence on foreign naval movements in the event of war or heightened tension. In practice, the system proved a failure. Britain cut Germany's overseas cables in August 1914, cutting off contact between N and many of its operatives abroad. In 1915 the Admiralstab instructed most of its overseas agents to discontinue their activities. In addition, the German navy's operational plans changed so frequently that it made it almost impossible to undertake long-term intelligence-gathering.

In 1914 there was no organized radio reconnaissance in the German Imperial Navy, but only a radio monitoring service - B service (B-Dienst), which was carried out from aboard the fleet ships When they begun around 1907/08, to listen to the radio communications of the British Navy, the service was seeking insight on how technical communication were achieved. The News service wasn't specifically looking to achieve tactical or operational superiority, but rather to get to know the state of radio engineering development in the Royal Navy and to track it. The monitoring was carried out by Radio Station Heligoland, the vessel SMS ZEITEN, a fishery protection ship and a trawler for communication tests. The fact that Britain used plain language in the text and call address was not evaluated.

Proud of their technical performance, the Imperial Navy were considered naive and careless with their own key processes, and associated radio traffic. No strategy was formed to determine or investigate the purpose for which the enemy was listening to radio messages, what experience they gained from it and what countermeasures the Imperial Navy could initiate against them. The wireless operation was conducted according to internationally developed procedures. To encrypt messages you used in optical signal service, as well as radio communications, the Secret Code of Signals (German Code Book), which was valid from 1 April 1914. Most three-digit groups that signal book were the war Signalbuch key, a replacement panel, via encrypted.

Two events were particularly significant, illustrating the lack of foresight on Germany's part, with the resulting success of the enemy:

The first incident, occurred soon after the outbreak of the world war 1, when a radio officer aboard one of the units of the German High Seas Fleet succeeded in breaking their own cipher. His report on the subject did not result in the changing of the cipher system, merely resulting ion a reprimand for himself, as he had searched into reports which were only for high level staff. The cipher system was continued in use.

The second such incident illuminates the outcomes from lack of focus on key processes. On 26 August 1914, the Imperial Navy light cruiser SMS Magdeburg was ordered to sweep for Russian reconnaissance forces in the entrance to the Gulf of Finland when dense fog closed in. It subsequently ran aground off the lighthouse at Odensholm on the Estonian coast. All attempts to re-float the ship failed. The Russian cruiser Bogatyr and Pallada appeared and shelled the stranded cruiser. The Germans destroyed the forward section of the ship, but could not complete her destruction before the Russians reached the Magdeburg. The on-board cipher agents and code books were weighted down with lead and thrown over board but were later rescued by Russian divers. The German code books were not destroyed; the Russians were able to recover three of the books, along with the current encryption key. They passed one copy to the British Royal Navy via a pair of Russian couriers on 13 October. The capture of the code books proved to provide a significant advantage for the Royal Navy. The cryptanalysts of Room 40, Britain's own recently created cryptanalysis department, was able to read all German naval radio traffic from them on. With the code books and cipher key, the British were able to track the movements of most German warships; this information could be passed on to the Admiral John Jellicoe, the commander of the Grand Fleet. Indeed, broken radio messages would be read by Jellicoe with a delay of between 30 minutes and 1 hour, which fully explained the tactical attitude taken by the Admiralty. In contrast it took the Germans up to two weeks to crack the radio signals of the British at the Battle of Jutland. [9] This allowed the British to ambush parts of or the entire German fleet on several occasions, most successfully at the Battles of Dogger Bank in January 1915 and Jutland in May 1916.

Only in the summer of 1917, did the Imperial Navy change the encryption key agent so that the radio communications of the Imperial Navy could no longer be deciphered. Until this reorganization, the British succeeded in deciphering every intercepted German message. It was said up to 2000 messages a day were read by the Room 40 cryptanalysts. Indeed, Germany still continued to believe that treachery and British secret agents were to blame.

The lack of focus on key processes, mistakes in daily operational activities and in addition, the German navy's operational plans changed so frequently that it made it almost impossible to undertake long-term intelligence-gathering, meant that the Nachrichten-Abteilun activities made little impact on the outcome of the war. However, it should be pointed out that within the German naval intelligence service, there was no close liaison between high-level staff and the main intercept station at Neumünster, which was so necessary, which was at a great distance from the naval war staff and operated almost independently.

Interwar Period (1919 to 1939)
The Nachrichten-Abteilung came to an end in 1919 after the Treaty of Versailles, which prohibited Germany from having any intelligence organization whatsoever. and the November revolution. As a result, the News Service was dissolved, with Fritz Prieger, its former head of foreign intelligence gathering, in charge of the winding-up of the agency. All monitoring, decoding and evaluation services had ceased. However, in April 1919, the organizer of the B-service, Lieutenant Brown, was tasked with restarting the service by Rear Admiral Adolf von Trotha, and by 28 April 1919, the central office was recreated at the same time as the new German Navy, the Reichsmarine was being created. The radio intelligence service needed comparatively little budget to operate and operated on very modest basis. The main intercept station had only three deciphering experts, with only two of them with sufficient depth of knowledge to make efficient decipherable possible. An officer to take command of the operation was not appointed until 1922, but was still handicapped because the thread of continuous decipherment knowledge was broken in 1918.

Organization
The MND led the organization, as they apparently had proved during the war. Under the command, naval intelligence officers at the coast radio and marine signal places ran the message service. The staff has been provided by the 2nd admirals. On the big ships, one of the radio rooms was established for the radio monitoring service. they had to be equipped with a radio direction finder, so that radio messages of other navies could be absorbed from there. The management of the MND was subject to its adoption


 * Lieutenant Martin Brown October 30, 1919 until April 28, 1920.

The development of radio intelligence service during the period 1920 to 1939 was characterised by lack of funds. A lack of focus by the command officer, the naval officer who was responsible for radio communications, was also responsible, in a kind of collateral duty for radio intelligence, meant little time for the service. From 1922 onward, the Chief of Naval Communications had a naval officer assisting him.

From 1921-1925, the service was temporarily moved to the Naval Academy in Flensburg-Mürwik, as the news department (MNA) of the Imperial Navy. While at the Naval Academy, the service did not undertake any radio reconnaissance, but radio metrology, direction finding and signal training. The MNA was led by:


 * Lieutenant Commander Ferdinand Boehmer --- March 29, 1921 until March 29, 1924
 * Lieutenant Commander Leo Riedel --- March 30, 1924 to March 27, 1925

By moving to Keil, German radio intelligence was deprived of the direct link with Navy High Command, as well as other military departments, e.g. Ministry of Armed Forces, and lost connection with sources of intelligence which were indefensible for its operation.

From the 1920 on-wards, British publications like Naval Operations  by British historian Sir Julian S. Corbett and from the memories of Baron Fisher, Admiral of the Fleet Jellicoe and Churchill were read by MND, and it was discovered how successful the British Admiralty had been in the use of radio decoding (German:Funkentzifferung), that characterized all of the operations of the German High Seas Fleet  had been seen through so early, that the British Grand Fleet could react in good time. This operation resulted in profound changes in the organization of the naval intelligence service in Germany.

In spring 1925, the Naval Intelligence Division was disbanded. For several years there was no official Navy Intelligence Service in Germany.

In the autumn of 1927, the scandal which would be later be called the Lohmann Affair (The Lohmann Affair) became public. This was the secret and illegal actions of the chief of the maritime transport department in the Marine line, Captain Walter Lohmann. Lohmann had promoted inter alia, the establishment of a non-official German intelligence service abroad, which was missed by the press and completely violated the Versailles Treaty. Lohmann oversaw millions of marks' worth of clandestine funding for secret Naval projects during the Weimar Republic.

In autumn 1929, for the first time, a naval officer was appointed as the head of the Main Intercept Station. The entire intercept staff of 10 removed from the Navy department and incorporated with the Torpedo and mining inspectorate at Keil.

In the 1930s, Naval Captain (German:Kapitän zur See) Gustav Kleikamp, while at the Kiel News Research Institute investigated the use of Naval Intelligence techniques during the proceeding years, and particularly in the first world war. Captain Gustav Kleikamp was the former radio officer aboard the battlecruiser SMS Derfflinger, and who in 1923-1926 was teacher at the marine torpedo and signalers school. In his capacity, Kleikamp authored a documentary, the 1934 secret service bulletin No.13, in which he described in detail the unwary radio use of the Imperial German Navy during World War I at length, and [which his stated outcome] in which he, for the planning and management of future naval warfare:


 * careful preliminary work in peace was required.

Thus, the program for the re-establishment of a Navy Intelligence Service was created.

Captain Gustav Kleikamp would later, as Captain of the battlecruiser, SMS Schleswig-Holstein, fire the first shots of world war 2.

In the fall of 1934, the official Navy News Service returned to the Naval Command (Department A III) as an independent department. Head of the Department was:


 * Captain Theodor Arps --- October 1, 1934 to December 31, 1939

In 1934, the top organization of the Main Intercept station, or B station numbered about 20 personnel. Two were naval officers, while two were leading decipherment analysts. The organization of Department AIII was as follows:


 * Department AIII
 * Section AIIIa: Communications
 * Section AIIIb: Radio Intelligence (plus means of development of decipherment)
 * Group FM: Foreign Navies

At Falshöft, the Department was now divided into the units of foreign navies, message transfer service and radio reconnaissance. The Group, foreign navies (FM), was divided into three sections, which were supplied with all incoming messages concerning foreign navies: the Abwehr, naval Attaché, the press and radio intelligence. Group FM started to compete with Section B, primary because the head of Department AIII (Arp), had once been head of Group FM, and had a tendency to overrate the information coming from sources other than section AIIIb. Further, the department head was senior in rank to head on section B, and who insisted that this was observed. Significant friction existed between departments, with section AIIIb fighting for Independence. In 1934/36, the branch which implemented own means of decipherment was changed from section AIIIb to section AIIIa.

Within the High Command of the Navy (Oberkommando der Marine), the Naval Intelligence department was incorporated into the Department of Naval Warfare and Operations (3/Skl) (German:Seekriegsleitung) on the 1 October 1937. At the same time, the Navy Intelligence message inspection emerged from the torpedo Inspectorate as an independent Department of the Baltic Sea naval station. You were the Navy message school, the Marinenachrichtenmittel laboratory, and the Marinenachrichtenmittel test command. The General Navy Office (B) founded the Department technical communications at the same time. She was affiliated to the Admiralty main weapon when the war started as the official group NWa.

At the same time went Naval Intelligence inspection as an independent department of the naval station Baltic apparent from the torpedo inspection. Your naval news school, the Naval Intelligence Central Research Institute and the Naval Intelligence agent test command were subordinated. In general, the Admiralty (B) at the same time the department was established in Technical Communication Services. It was when the war began as an official group NWa the Naval Weapons main office affiliated.

The 3rd Division / Naval Operations (3rd / SKL) was aware that in case of war the enemy would commit to create the greatest difficulties for the German radio reconnaissance:

do everything in the German radio reconnaissance to prepare the greatest difficulties:


 * He will change Mob. case the radio name and all key agents, It's gained a lot if it does not change the individual systems. This possibility, however, can be denied to a certain degree, because all experiences and the enemy a serious threat to its own messaging service created when he (...) wants to introduce completely new key systems in the event of mobilization.

So, they remained confident that the slump in the opposing key procedures in the event of an emergency would be maintained. Quite differently, however, the naval staff evaluated the security of their own key medium. In a presentation in March 1938 by Lieutenant Commander (German:Korvettenkapitän) Fritz Bassenge led off:


 * All key systems and combinations [are] devised by man and therefore also again to be solved by man

If however, the traffic is based on the codes of secret key machines, a backtracking on the plaintext message is


 * Possible only with so huge usage an outlay of staff and so many available transmission equipment, numerous available radiogram material, that there are limits to the practical implementation [of decipherment]

stated Bassenge so important that the good results with the remote control key "M" towards all foreign states remained secret, because by the introduction of mechanical keys at the opponent radio reconnaissance would be more difficult with unpredictable consequences.

Intercept Stations
In 1920, naval radio stations for the use by Radio Intelligence to monitor foreign naval radio traffic consisted of the following: On the North sea coast, Borkum,Wilhelmshaven, Nordholz, List and at Falshöft, Neumünster, Kiel, Arkona, Swinemuende, Pillau in the Baltic. The geographical location of the intercept stations were considered unfavorable for the most efficient operation, in particular when bearings were taken that proved less than accurate. Initial, operators were untrained, but continuous monitoring soon sharpened practices. During the early years, processes remained unchanged. The operational and organization use of the stations changed later, with Wilhelmshaven, Swinemuende and Kiel being reassigned with only one station, at times only 1 Bereich being available for B-Dienst. A Bereich was the name of a monitoring unit consisting of one operator, and 1 or two receivers, i.e. minute intercept station.

Operational tasks of the intercept stations was assigned based on the metrics: geographical location, their size and equipment, that quality of reception in the short, medium and long wave band. Interest was focused not only on normal tactical targets (traffic sent from maneuvers or training), but radio traffic dealing with orders, reports. Navy Radio South was created, placed under a commanding officer and consisted of 3 Bereich.

In 1925, a plan was executed to create an interception station (Codename:MNO:Sued) as far southwest as possible, to monitor the Mediterranean. A station was created in the village of Villingen-Schwenningen in the Black Forest, as the demilitarized zone (Rhineland) area was not found to be suitable, i.e. camouflage provisions. Conditions were found to be not suitable and in Autumn 1926, the MNO:Sued subsequently moved close to the town of Landsberg am Lech. When conditions changed, i.e. lack of the need for camouflage, MNO:Sued moved to a specifically constructed facility at Langenargen, close to Lake Constance, which was tested to ensure excellent bearing and reception conditions were excellent.

By 1936, the importance of linking the stations with the Main Intercept Station by the teletype was known. Initially the general Navy teletype net was used to link coastal stations and Berlin, but gradually a specialized Radio Intelligence teletype net was created to link all the stations. After Austrian Anschluss in 1938, an Intercept Station was established outside the town of Neusiedel am See, for tracking Russian naval radio traffic in the Gulf of Finland and the Black Sea.

The Unit radio reconnaissance operation in 1937-38 had a central control center in Berlin, three other control centers (North: Neumünster, middle: Soest, South: Langenargen), four main bearing radio sets(Wilhelmshaven, Flensburg, Swinoujscie, Pillau) and eight targeting stations along the North and Baltic Coast (Borkum, Cuxhaven, Arkona, Darss, Falshöft, Ustka, Memel, Windau). In March 1939, the B-Service observed a total of 36 radio traffic areas, including 14 British, 10 French and 10 Russian. When decoding, the B-Dienst had 20 radio key process desks, of which 7 were English, 5 were French and 4 Russian. In 1938, the B-Dienst managed to decipher about 80% of tactical signal immediately from a French naval exercise.

World War Two (1939 to 1945)
The Naval Intelligence Division was split in January 1940. The two units of foreign navies and radio reconnaissance now formed the Department of Navy message evaluation (3. / SKL). Their task consisted in the collection and analysis of information about foreign naval forces and fleet bases, positioning and composition of battle group (task forces), ship detection, technical data, etc. The head of this Department were:


 * Captain Paul Wever - January 1, 1940 to 21 June 1940
 * Gottfried Krüger - Captain June 22, 1940 to July 1942
 * Captain Norbert von Baumbach - July 1942 to 28 June 1944
 * Rear Admiral Otto Schulz - June 28, 1944 to 17 Jul 1945

The newly established Department of Naval Intelligence (2 SKL, later 4th / SKL) was in January 1940 in the Central Department and the mail submission service. But already in June 1940, the Department followed by radio intelligence. The Navy message inspection was dissolved in June 1941. The Navy intelligence took over its tasks, thus became the official group and was divided into three departments:


 * Central Division (MND I)
 * Mail submission service (MND II)
 * Radio education (MND III).

A further Department was with the radio measurement service in October 1943. This was in June 1944 in the Department of Navy location service (5/SKL) on. Instead the Department wire news service (MND IV) was annexed. Departments and from 1941 group heads of the Office of the MND were:


 * Captain Ludwig Stummel - 1 January 1940 – 15 June 1941
 * Vice Admiral Erhard Maertens - June 16, 1941 to May 1943
 * Rear Admiral Louis Stummel - May 1943 – 16 August 1944
 * Captain of the Lake/Rear Admiral Fritz Krauss - 16 August 1944 – 22 July 1945

Head of the Department of radio education, as B-Dienst was called, throughout the war was Captain Heinz Bonatz, frigate Captain Hans Meckel was head of the tracking service. This is mentioned here because the location service was always a part of the naval intelligence service after course understanding.

In contrast to the now world famous successes of the British radio intelligence at Bletchley Park, the successful Entzifferungen of the B service are little known. Actually, there were successes but also here. The slump in the British radio controlled key naval cipher No.3 (German code name "Frankfurt"), the allies were using for their Atlantic convoys was particularly important. The Commander of the submarines, Admiral Dönitz, this helped to focus on the, German U-boats operating in the Atlantic on the Allied convoys. But were the successes of the U-boats behind the expectations far back as Bletchley Park to capture German key documents in turn could decipher the U boat radio messages and evaluate. From then on, the convoys to the enemy U boat lineups were routed around or with strong escort safety "pushed through".

Literature

 * Friedrich L Bauer: Die Komödie der Irrungen im Wettstreit der Kryptologen. Vortrag vom 14. Dezember 2007. Bayerische Akademie der Wissenschaften: München 2008 (Abhandlungen, Neue Folge, Heft 176)
 * Heinz Bonatz: Die deutsche Marine-Funkaufklärung 1914–1945. Wehr und Wissen: Darmstadt 1970. (Reihe Beiträge zur Wehrforschung Band 20/21. ISSN 0067-5253)
 * Heinz Bonatz: Seekrieg im Äther. Die Leistungen der Marine-Funkaufklärung 1939-1945. E.S. Mittler: Herford 1981. ISBN 3-8132-0120-1
 * Ralph Erskine: Enigma’s Security: What the Germans Really Knew. In: Michael Smith and Ralph Erskine (eds.): Action this day. Bantam Press: London 2001, S.370-385. ISBN 0-593-04910-1
 * Helmuth Giessler: Der Marine-Nachrichten- und Ortungsdienst. Technische Entwicklung und Kriegserfahrungen. J. F.Lehmann: München 1971, (Reihe Wehrwissenschaftliche Berichte Band 10. ISSN 0083-7822)
 * Hans H. Hildebrand, Walther Lohmann: Die deutsche Kriegsmarine. 1939–1945. Gliederung, Einsatz, Stellenbesetzung. Podzun: Bad Nauheim 1956, Kapitel 32.
 * Hans H. Hildebrand: Die organisatorische Entwicklung der Marine nebst Stellenbesetzung 1848 bis 1945. 3 Teile. Biblio-Verlag: Osnabrück 2000 (Reihe Formationsgeschichte und Stellenbesetzung der deutschen Streitkräfte 1815-1990 Band 2). ISBN 3-7648-2541-3
 * Werner Rahn: Warnsignale und Selbstgewissheit. Der deutsche Marine-Nachrichtendienst und die vermeintliche Sicherheit des Schlüssels M („Enigma") 1943/44. In: Militärgeschichtliche Mitteilungen 61 (2002), S.141-154
 * Werner Rahn: Der Einfluss der Funkaufklärung auf die deutsche Seekriegführung im Ersten und Zweiten Weltkrieg. In: Winfried Heinemann (Hrsg.): Führung und Führungsmittel. Militärgeschichtliches Forschungsamt, Potsdam 2011 S.15–56
 * Rebecca Ratcliffe: Searching for Security. The German Investigations into Enigma’s Security. In: Intelligence and National Security 14 (1999) Heft 1 (Special Issue) S.146-167.
 * Rebecca Ratcliffe: How Statistics led the Germans to believe Enigma Secure and why they were wrong: neglecting the practical mathematics of ciper machines. In: Brian J. Winkel (Hrsg.)The German Enigma Cipher Machine. Artech House: Boston, London 2005.
 * Jürgen W. Schmidt (Hrsg.): Geheimdienste, Militär und Politik in Deutschland. Ludwigsfelder Verlags-Haus: Ludwigsfelde 2008. (Reihe Geheimdienstgeschichte Band 2). ISBN 978-3-933022-55-4
 * KKpt. Achim Teubner, März 1939, zitiert bei Werner Rahn: Die Funkaufklärung in der Reichs- und Kriegsmarine 1919-1939. In: Heinemann, 2011
 * Jürgen W. Schmidt (Hrsg.): Geheimdienste, Militär und Politik in Deutschland. Ludwigsfelder Verlags-Haus: Ludwigsfelde 2008. (Reihe Geheimdienstgeschichte Band 2). ISBN 978-3-933022-55-4
 * KKpt. Achim Teubner, März 1939, zitiert bei Werner Rahn: Die Funkaufklärung in der Reichs- und Kriegsmarine 1919-1939. In: Heinemann, 2011