World War II German U-Boat Captains' War Diaries U.S. Naval Intelligence Translations - Download

World War II German U-Boat Captains' War Diaries U.S. Naval Intelligence Translations

4,962 pages of translations of U-Boat logs and diaries kept by the captains (leaders) of German U-boats for Norway/Arctic Ocean and Italy/Mediterranean, translated by the United States Office of Naval Intelligence.

The content of these diaries/journals were kept classified for 33 years after the World War II ended.

U-boat is the anglicized version of the German word U-Boot, a shortening of Unterseeboot, which means "undersea boat." During World War II, U-boat warfare was the major component of the Battle of the Atlantic, the longest battle of World War II, which lasted the duration of the war. Germany had the largest submarine fleet in World War II, since the Treaty of Versailles had limited the surface navy of Germany to six battleships. During the Second World War over 250 Allied warships from a dozen navies were sent to the bottom by German U-boats. 

An important component of any serious research into German submarine warfare should be the use of these war logs or war diaries of the headquarters that controlled U-Boat operations. The logs and diaries in this collection were part of the German Navy Archives seized in April 1945 at Castle Tambach, Coburg, Germany. 

The reader will observe that the peaks and valleys of the various U-Boat campaigns during World War II are punctuated in the War Logs by the Commanding Officers. This is noted in the current operations and general situation sections of the logs as well as various orders, appendices, and correspondence included in the logs.

The war journal (Kriegstagebuch, or KTB) was a daily narrative summary of U-Boat operations, claimed successes, losses, intelligence reports, perceived lessons in tactics and equipment, organizational matters, and discussions of legal and strategic issues. The daily entries usual included (1) U-Boat locations; (2) aerial reconnaissance results; (3) reports of Allied movements and activities, including signal intelligence assessments; (4) current operations, including losses of individual submarines; (5) reported successes; and (6) general observations. 


Diary of the Leader of U-Boats, Italy/Mediterranean, 1941-1944

The position of Leader of U-Boats, Italy (Führer der Unterseeboote Italien, or F.d.U. Italien), was created in November 1941 from the operational areas of responsibility of the B.d.U. in the Western Mediterranean and of the Admiral, Aegean Sea (Admiral Ägäis), in the Eastern Mediterranean, and was redesignated Leader of U-Boats, Mediterranean, in August 1943. The position, which was operationally subordinate to the Commander of the German Naval Command, Italy (Befehlshaber des Deutschen Marinekommandos Italien), was held successively by Korvettenkapitän Victor Oehrn (entrusted with carrying out the duties of the position, November 1941 to February 1942), Konteradmiral Leo Kreisch (February 1942 to January 1944), and Kapitän zur See Werner Hartmann (January 1944 to September 1944). For purposes of personnel administration, the Leader of U-Boats, Italy/Mediterranean, was subordinate to the B.d.U.Org. Reflecting the course of the war in the Mediterranean, the position of Leader of U-Boats, Mediterranean, was disestablished in September 1944. 

Operations in the Mediterranean were centered on disrupting the British supply route through Gibraltar and the Suez Canal as well as disrupting supplies in support of the North African campaign. Heavy losses were experienced by U-Boats operating in the Mediterranean due to aircraft and shallower, clearer waters. 

Notable entries within these volumes include Operation VIGOROUS, a failed convoy from Alexandria to Malta (PG 30925), and U-Boat intelligence on the Allied landings in November 1942 during Operation TORCH, the invasion of North Africa (PG 30928). Also the amount of intelligence gathered by U-Boats in the Mediterranean is present in these volumes. One example of this is Admiral Kreisch’s notes on Allied preparations for Operation HUSKY, the invasion of Sicily (PG 30931, page 422). Also the logs note the size and movements of the Allied landing force during HUSKY (PG 30932, page 479). In his synopsis of the month of August 1943, Konteradmiral Kreisch noted advanced preparations in Sicily for an Allied landing on the mainland of Italy (PG 30933, page 635-642). There is a gap in the War Logs between 31 August 1943 and 16 October 1943, and there are no volumes covering the period after 15 January 1944. The volumes comprising this series are as follows:


1. U-Boats Italy 8 Dec 1941 – 30 Jun 1942. PG 30920-30925. 

2. U-Boats Italy 1 Jul 1942 – 31 Dec 1942. PG 30926-30929. 

3. U-Boats Italy 1 Jan 1943 – 30 Jun 1943. PG 30930-30931. 

4. U-Boats Italy 1 Jul 1943 – 31 Aug 1943. PG 30932-30933. 

5. U-Boats Italy 16 Oct 1943 – 15 Jan 1944. PG 30933-30934. 



Diary of the Leader of U-Boats, Norway/Arctic Ocean, 1943-1944

The position of Leader of U-Boats, Arctic Ocean (Führer der Unterseeboote Nordmeer, or F.d.U. Nordmeer) was created in January 1943 under the operational control of the Admiral, Arctic Ocean (Admiral Nordmeer), and was commanded successively by Kapitän zur See Rudolf Peters (formerly the Chief of the 7th U-Boat Flotilla) and Fregattenkapitän Reinhard Suhren. Prior to this the post of Admiral, Arctic Ocean (Admiral Nordmeer), was directly responsible for U-Boat operations. 

The existing war logs of the Leader of U-Boats, Arctic Ocean, cover the time period from January 1943 to October 1944. Although war journals post October 1944 have not been found, the position of Leader of U-Boats, Norway, operated through the end of World War II. In these logs are discussions surrounding successful U-Boat operations known as “Wunderland”, directed against the Allied Arctic supply route in the summers of 1942 and 1943 (PG 31835, page 354). Weather and ice patterns in the Arctic Ocean played a significant role in U-Boat operations against Allied shipping. Assessments of these conditions are prevalent through the War Logs of the Leader of U-Boats, Arctic Ocean.  In addition the war logs cover the German assault on the island of Spitzbergen, OPERATION SITRONELLA/SIZILIEN (PG 31843). There is an in-depth account of the sinking of the German battleship Scharnhorst by British ships on 26-27 December 1943 (PG 31849, pages 910-918). 

In May of 1944 Fregattenkapitän Rheinhard Suhren, a renowned U-Boat captain who commanded U-564 from April 1941 to October 1942 and later was a group leader with the 27th U-Boat Flotilla (a training command) from March 1943 to May 1944, took over from Kapitän zur See Peters as Leader of U-Boats, Arctic Ocean (PG 31859, page 915). Also of note is the reaction to the invasion of France and concern of an imminent invasion of Norway (PG 31860, pages 1010-1011). The volumes comprising this series, which was translated under the erroneous title of U-Boats Norway on account of the fact that the submarines operated out of Norwegian ports, are as follows:

1. U-Boats Norway 18 Jan 1943 – 30 Jun 1943. PG 31827-31837. 

2. U-Boats Norway 1 Sep 1943 – 15 Oct 1943. PG 31842-31844. 

3. U-Boats Norway 16 Oct 1943 – 31 Dec 1943. PG 31845-31849. 

4. U-Boats Norway 1 Jan 1944 – 31 Mar 1944. PG 31850-31855. 

5. U-Boats Norway 16 May 1944 – 1 Jul 1944. PG 31859-31862. 

6. U-Boats Norway 1 Aug 1944 – 14 Oct 1944. PG 31863-31866. 


The German Navy archives, seized by Allied forces at Castle Tambach near Coburg in April 1945, were transferred by agreement to the British Admiralty for exploitation.  In London the records received new file designations according to the British registry system:  each record item was assigned a number and prefaced with the designation "PG" (reportedly an abbreviation for "pinched from the Germans"). The U.S. Navy's Office of Naval Intelligence (ONI) microfilmed the great majority of these materials during the period Aug 1945-Jul 1947.  In 1955 the Admiralty began the restoration of the German naval records to the Bundesarchiv-Abt. Militärarchiv in Freiburg; the U-boat war journals, however, were not declassified and returned to German custody until 1977.  Between 1968 and 1978 the National Archives accessioned the Office of Naval Intelligence microfilm from the U.S. Navy as microfilm publication T1022; after declassification by the British the U-boat war journals became generally available for research in 1978.

The war journals described are not synonymous with ship's logbooks, but are narratives of combat operations.  Training activities and periods in port for layover or repair are generally only summarized; detailed entries are found only for the periods of service at sea.  War journal entries include data on sea and meteorological conditions, radio communications received and sent, times and duration of submergings, a daily record of distances traveled on the surface and submerged, and all pertinent information concerning combat actions.  

The amount of detail varies according to the style of the commanding officer, who was responsible for the journal's maintenance.  Following the war journal for each completed patrol is an analytical commentary by the Operations Department of the Commander in Chief of Submarines (Befehlshaber der Unterseeboote) or by one of the U-boat theatre commands, these are often accompanied by radio logs and torpedo-firing reports.  The submarines positions and movements are identified according to the grid-coordinates of the standard German chart, rather than latitude and longitude.  Mission orders are generally not included, and the accomplishment of such special missions as the landing of agents on enemy coasts is sometimes noted only as "executed" without the nature of the mission being specified. 

For most of the U-boats lost in action before March 1944, the Befehlshaber der Unterseeboote reconstructed a war journal of the last war cruise on the basis of the radio communications exchanged and subsequent intelligence information on the manner of the boat's loss and the fate of crew members.  No attempt was made to fix the exact location of U-boat sinkings.  The final date given for the span of a war journal often indicates the last date that communications were transmitted to the U-boat, rather than the actual date of loss.  For submarines sunk during the period after March 1944 such reconstructions are lacking, and the descriptions have drawn upon the war diaries of U-boat operational commands and other German Navy records to indicate known losses.

As these are German Navy records, they reflect the information available to German authorities at the time.  Postwar determinations of U-boat claims and losses have not been included, with the following exception:  where U-boat's correctly claimed the sinking of Allied warships but could not identify them, the names or numbers of the latter have been added in parentheses.  Except for ships of major significance (e.g., "Athenia," "Laconia") and ships from which prisoners were recovered, the names of merchant vessels sunk by U-boats are omitted from the descriptions.


Source: National Archives and Records Administration and the United States Navy Department Library Naval History & Heritage Command