Hunt and Kill

by Theodore P. Savas

  Lange peered through the periscope as U-505 approached Brest and discovered they were some miles off course; the boat’s direction finder was malfunctioning. He radioed the headquarters of Brest’s 1st U-boat Flotilla for instructions and the glaring beam of the lighthouse at Pointe de Penmarc’h was illuminated for his benefit. Escort ships shepherded the U-boat past Pointe St Mathieu and into Brest harbor on the morning of January 2, 1944. En route through the entrance channels a barge loaded with war correspondents pulled alongside U-505 and, much to the crew’s chagrin, climbed aboard with heavy camera equipment to film the confined interior. As they did water leaked into the electric motors’ accumulator panel and a massive flash and huge blue bolt of electricity arced across the starboard motor, sending thick white smoke billowing through the U-boat and starting a small fire. The terrified newsmen rushed headlong for the control room and the exit hatch, their panic infecting the T25 survivors as well. For U-505’s crew it was business as usual, for the problem had happened once before. With CO 2 fire extinguishers in hand the small conflagration was quickly smothered. The U-boat men shook their heads in weary resignation. “It just wouldn’t have been the U-505 if something like this hadn’t happened,” explained Hans Goebeler.39

  When the chaos subsided U-505 eased its way toward Brest’s huge U-boat bunker, similar to those they had left not so long ago in Lorient. The headquarters staffs of the 1st U-Flotilla and 5th T-Flotilla were present, as were many other blue uniforms and even a brass band, harking to the bygone age of earlier days. One final indignity awaited U-505 as it entered wet-pen C1. A group of torpedo boat sailors, overjoyed to be nearing their home base, rushed to disembark from the boat. In their haste to climb outside one of them slipped from the vertical ladder and landed squarely on the helmsman, causing U-505 to swerve to starboard and brush the concrete mooring bay. The crash bent the forward dive plane’s shaft, a serious injury that would require dry-docking and two weeks of repairs before it could put to sea again. Later, as Lange pondered the bizarre twist of his boat’s latest misfortune, insult was added to injury when he was informed the nearest replacement shaft was in Bordeaux. It would be considerably longer than a fortnight before U-505 sailed again.

  In fact, it was not until March 16 that U-505 was able to leave port on its twelfth war patrol. The boat sailed at 1835 from Brest alongside U-373 and U-471, a pair of Type VIICs skippered by Detlef von Lehsten and Friedrich Kloevekorn. Lange entered the Bay of Biscay before separating from his escorts at 1025 the following morning, the departure of the Vorpostenboote marking the official beginning of what was to be U-505’s last war patrol. His fellow U-boats submerged to begin crossing the Bay of Biscay, the “Valley of Death” where so many boats and men had been lost to enemy aircraft and naval forces. Unlike his companions, however, Lange elected to remain surfaced as much as possible, risking extended diesel sprints rather than creeping continually submerged beneath the heavily patrolled waters. His gamble paid off and U-505 cleared the “Valley” in good time. He emerged from the outer Bay of Biscay on March 25. According to Hans Decker, the boat came upon the incoming U-154 and “passed the new radio code on to her.” In the exchange of information “we heard, too, for the first time of the new Allied Hunter-killer groups, composed of small aircraft carriers and destroyers, that were raising havoc with our U-boats.”40

  And so U-505 headed for the hunting grounds off Freetown, the west coast of Africa—and a fateful rendezvous with a Task Group 22.3.

  The staff of the Supreme Naval Command repeatedly told Karl Dönitz—and he believed it—that the use of high frequency radio would make direction finding impossible. Kriegsmarine scientists were even more reluctant to consider the possibility that the Allies were installing HF/DF gear aboard ships. Not until June 15, 1944, when U-505 was already en route to Bermuda under tow, did BdU send a message to the fleet warning of the threat from shipborne HF/DF. By that late date, of course, much of the damage had already been done.

  Mark E. Wise and Jak P. Mallmann Showell

  Deciphering the U-boat War

  The Role of Intelligence in the Capture of U-505

  From its earliest days of construction through its final hours of life as a frontline Unterseeboot, U-505 had been the subject of Allied intelligence reports. It was regarded as just another enemy submarine, however, until Captain Daniel V. Gallery reported her capture on June 4, 1944.

  Photographic intelligence alerted the Allies to U-505’s early existence when aerial reconnaissance revealed in early 1941 another Type IXC U-boat under construction at the Deutsche Werft shipyard along the Elbe River in Hamburg. At that time, of course, the photo interpreters of the RAF Reconnaissance Unit had no way of knowing its hull number.1 The last time U-505 became the subject of Allied interest was during its final war cruise, when signals intelligence in the form of high-frequency direction finding (HF/DF) and decrypted Enigma messages revealed to the U.S. Navy U-505 was on patrol. This intelligence indicated its general operating area with enough precision to allow U.S. Navy analysts to predict the boat’s position more accurately than Karl Dönitz’s BdU staff. Earlier intelligence gleaned from prisoner interrogations had allowed the Office of Naval Intelligence to draw up deck plans, copies of which had been given to Gallery’s boarding parties to study should the opportunity to board a U-boat arise.

  Intelligence continued to figure into the U-505 story after its capture. The submarine and its contents, together with interviews with members of its crew, provided a colossal windfall for the Allies. In particular, the Enigma keys discovered aboard freed up U.S. naval cryptanalytical assets, which were thereafter devoted to decrypting Luftwaffe and Wehrmacht message traffic as the Allied invasion of Europe progressed.2

  It is impossible to understand how all this came about, however, without a full appreciation of the key organizations, people, and history leading up to U-505’s final war patrol.

  United States Naval Intelligence Organizations

  Relevant to the Capture of U-505

  The organization and reorganization of U.S. naval intelligence during World War II arose directly from Admiral (later Fleet Admiral) Ernest J. King’s dissatisfaction with the existing structure when America entered the war. King was appointed to the post of Commander in Chief, United States Fleet (COMINCH) on December 20, 1941. Within a month he established a Fleet Intelligence Officer billet in the Plans Division of his headquarters, effectively ignoring the Office of Naval Intelligence (ONI).3 Over the next eighteen months King, who had been pulling double-duty as Chief of Naval Operations (CNO) since March 12, 1942, reorganized his intelligence staff and established some unity of command between his COMINCH intelligence staff and ONI.4 On May 20, 1943, he established the Tenth Fleet under his direct control as an administrative organization to direct the U.S. antisubmarine effort. These disparate entities—COMINCH, ONI, and Tenth Fleet—cooperated with each other and with parallel British units to support the operating forces in their successful campaign against the U-boats.

  COMINCH

  Because King believed ONI was too large and too slow to respond to the demand for operational intelligence, he put together a lean fleet intelligence staff of approximately 30 people to handle the task.5 The original staff, dubbed F-11, stood a continuous U-boat plotting watch. The officer in charge presented a daily briefing to King, his chief of staff, and all COMINCH officers working in antisubmarine warfare (ASW).6 King also brought an operational intelligence section of ONI, known as OP-38W, under his control in mid-January 1942. King named it F-35, the Operational Information Section of the Operations Division of COMINCH Headquarters. A tracking system based on available intelligence was set up in F-35 to detour convoys around known or suspected U-boat positions. Since access to F-35 was less rigidly controlled than access to F-11, highly classified operational details were plotted in the latter staff organization.7

  On July 1, 1943, a major reorganization of naval intelligence occurred. F-11 was converted into F-2, the Combat Intellige
nce Division, under Rear Admiral Roscoe E. Schuirmann. The tracking system formerly known as F-35 was dismantled and divided into three sections: F-21 (Atlantic), F-22 (Pacific), and F-23 (Operational Summaries). These three sections reported to F-20, Captain Henri H. Smith-Hutton, the Assistant for Combat Intelligence.8 Admiral King intended F-2 to be a small organization optimized for the rapid handling of operational intelligence, in contrast to ONI, which King saw as an organization better suited to handle noncombat-related information.9

  F-21: The Atlantic Section, COMINCH Intelligence

  Commander Kenneth A. Knowles, a 1927 Naval Academy graduate whom King personally recalled from medical retirement, served as the head of F-21.10 Early in his career, Knowles had served as gunnery officer aboard the destroyer Paul Jones (DD-230) under the command of Francis S. “Frog” Low, who was greatly impressed by the young officer. When the need for an antisubmarine intelligence entity became apparent, Low, by now a captain on King’s staff, convinced King to recall Knowles to the Atlantic unit of F-11, which (as noted above) evolved into F-21. Knowles sailed to England as soon as possible after his return to active duty. There, he worked closely with Lieutenant Commander Rodger Winn, the commander of the Admiralty’s Submarine Tracking Room, learning the half-science and half-art of submarine tracking.11 Returning to the United States, Knowles assembled F-21 on the British model. To reduce security risks and bureaucratic inertia he deliberately kept his unit small, with four male officers, eight Wave (Women Accepted for Volunteer Emergency Service) officers, two or three yeomen, and a “handful” of enlisted Waves.12

  Knowles’s most important initial duty was to track U-boats in the Atlantic, issue daily position estimates, and advise the staff responsible for routing convoys.13 Knowles and his staff would later combine Ultra intelligence from F-211 (when it became available; see below) and information from the high frequency direction finder network (HF/DF, or Huff-Duff), prisoner interrogations, action reports from Allied merchant ships and warships, air reconnaissance, and any other available source.14 Knowles also maintained a liaison with operational intelligence centers in Britain and Canada, communicating daily by teleprinter with Commander Winn in London and Canadian naval reserve officer Lieutenant Commander John B. McDiarmid, who performed a similar function in Ottawa.15 When the Tenth Fleet began operations, F-21 served as its operations plot. Its U-boat position estimates would prove vital to the Allied effort against Dönitz’s submarines.16

  F-211: The “Secret Room”

  Commander Knowles’s F-21 began operating during the Enigma blackout of 1942, after the Kriegsmarine added a fourth rotor to its Enigma machine. Until the Allies could break into the more complex coding system, there were no decryptable messages to exploit for their intelligence value, and thus no requirement for F-21 to handle this traffic during the section’s early months of existence. By December 1942, however, the codebreakers at the deceptively-named Government Code and Cipher School (GCCS) at Bletchley Park were furnishing four-rotor Enigma solutions to their American counterparts, and COMINCH had to make arrangements for the security of Ultra intelligence. Although Knowles set up tight security measures for F-21 and kept his staff intentionally small, task group commanders and other non-COMINCH personnel frequented the room.17 Obviously, more stringent precautions would be necessary for the protection of Ultra.

  The solution was the “Secret Room,” later known as F-211. The Secret Room was established on December 27, 1942, “to provide for the processing, from the operational standpoint, of special U/B intelligence obtained from radio intercepts.”18 Lieutenant John E. Parsons, USNR, served as officer in charge, assisted by Lieutenant (j.g.) John V. Boland, USNR, and Yeoman First Class Samuel P. Livecchi.19 In addition to Parsons and his assistants, only Knowles, who used the room constantly, and Ensign R. B. Chevalier, who acted as relief yeoman, had routine access to F-211. King, Vice Admiral Richard S. Edwards (King’s chief of staff), Low, Schuirmann, and Smith-Hutton visited occasionally, and rare visitors were admitted “with the approval of the Chief of Staff.”20

  F-211 worked closely with the Enigma section of ONI known as OP-20-GI-2, keeping abreast of the availability and interpretation of intercepted Enigma traffic. A secure telephone connected the two sections, and its users spoke in a voice code to enhance communications security. F-211 also maintained a liaison with OP-16-Z, the Special Activities Branch, to obtain the most current possible intelligence derived from the interrogation of prisoners.21 Officer messengers delivered Enigma traffic in sealed double envelopes. The staff abstracted the special intelligence for a daily location list that was used to maintain a plot in F-211 as well as the main board in F-21.22

  In addition to the daily plot, F-211 maintained a monthly plot of U-boats sunk and a 10-day plot of DF fixes.23 Sinkings were noted with the date, time, position, type of attack, and attacking forces involved. If prisoners were taken, a summary of the final action was added as F-211 received interrogation reports from OP-16-Z.24

  F-211 routinely shared intelligence with the British. The Admiralty’s Operational Intelligence Centre sent an “Ultra serial” to F-211 “almost daily.”25 Winn would add comments and queries before sending the message, and F-211 would draft replies and comments, which were sent in turn by F-21 serials. This two-way message traffic allowed Winn and Knowles to share information and keep each other fully informed of what the other was thinking. This practice began in 1942, when Bletchley Park was breaking Enigma traffic faster than OP-20-G, and continued even after the U.S. Navy outstripped Bletchley Park’s capabilities.26

  Office of Naval Intelligence

  Several important departments and sub-departments were developed to meet the requirements necessary to battle the Axis forces. An understanding of these organizations is necessary in order to appreciate fully the intelligence offensive waged against the U-boat war, though the names and descriptions of these departments can become difficult to keep straight.

  OP-16-Z: The Special Activities Branch

  The Special Activities Branch, or OP-16-Z, came into existence on August 5, 1942, the successor to the Special Intelligence Section (OP-16-F-9). OP-16-Z was responsible for interrogating prisoners of war and for foreign materiel exploitation.27 In addition to disseminating intelligence to Knowles’s F-21 and operating forces, OP-16-Z compiled and published reports for its own internal use. Interrogating officers used these reports, which detailed active U-boats, officers, and bases, as starting points from which to obtain additional information from new prisoners.28

  OP-20-GI-2 (A): The Enigma Section

  The responsibility for decrypting and translating Enigma message traffic belonged to the Enigma Section of the Office of Naval Intelligence, or OP-20-GI-2 (A).29 In addition to its decryption work, the Enigma Section maintained a card file on matters pertaining to U-boats. This file primarily served the translators and watch officers answering questions from F-21 and F-211, but was also used to find suggestions for “cribs,” or clues that could be used to speed the decryption of intercepted Enigma traffic.30 OP-20-GI-2 (A) also disseminated a daily U-boat summary, produced by Lieutenant Willard Van Orman Quine, USNR.31

  OP-20-3-GI-A: The Atlantic Section

  Yet another department that played an integral role in subduing the U-boat menace was the Atlantic Section, also known as OP-20-3-GI-A. This organization, a unit within OP-20-G, dealt more broadly with the operational intelligence situation in the Atlantic. Enigma provided but one of its many sources. OP-20-3-GI-A began operations in January 1943, with responsibility for translating U-boat message traffic, performing traffic analysis, and correlating D/F reports.32 The section’s primary mission was to furnish Knowles’s F-21 with an accurate interpretation of each message—a task complicated by the Kriegsmarine’s system of double-encoding U-boat positions. The Atlantic Section met this difficult challenge, but the code would require substantial extra analytical effort until a key to the Kriegsmarine grid-square system, the so-called Addressbuch, was captured with U-5
05.33

  To support Knowles, the Atlantic Section supplied its intelligence output to F-211 (“The Secret Room”) as quickly as possible. Operational use of Ultra intelligence was entirely Knowles’s responsibility, and he had his own system for analyzing Ultra and fusing it with information from other sources. In addition, the Atlantic Section supported Knowles’s work by preparing any special studies or reports he requested.34

  While Knowles shared intelligence with the Admiralty’s Operational Intelligence Centre, the Atlantic Section shared intelligence with the codebreakers working at Bletchley Park. With its coverage of local Kriegsmarine circuits as well as its greater experience with U-boats, Bletchley Park provided information and expertise that the Atlantic Section was unable to obtain elsewhere. In turn, as American bombes (machines built to read encrypted German transmissions) began breaking the four-rotor Enigma, the Atlantic Section shared the resulting Ultra intelligence with their British counterparts.35

  The Tenth Fleet

  Against the background of the tradition-rich United States Navy, the Tenth Fleet was notable for its oddities. It was the only fleet in the American Navy without ships. Its numerical designation was much higher than any other numbered fleet, and not a single other approached that integer. The commander of Tenth Fleet was none other than Admiral King, a position adding yet a third responsibility to his roles as Commander in Chief, United States Fleet, and Chief of Naval Operations.36 The Tenth Fleet had a remarkably small staff and most of its enlisted personnel were Waves.37 Tenth Fleet was indeed a unique organization.