28. NARA, RG 38, OP-16-Z (Special Activities Branch), U-Boat List, November 1, 1943; U-Boat Officers, October 12, 1943; U-Boat Bases, July 15, 1943.
29. Jennifer E. Wilcox, Sharing the Burden: Women in Cryptology During World War II (Fort Meade, MD: Center for Cryptologic History, National Security Agency, March 1998), 7.
30. Kahn, Seizing the Enigma, 241.
31. Ibid., 241-242.
32. NARA, RG 457, Office of Naval Intelligence, OP-20-G, History of Communications Intelligence in the Battle of the Atlantic: Allied Communication Intelligence in the Battle of the Atlantic, n.d., 3; Document SRH 008; Studies on Cryptology, 1917-1977, hereafter NARA, RG 457, COMINT History.
33. NARA, RG 457, COMINT History, 5-6.
34. Ibid., 6-7.
35. Ibid., 6.
36. Farago, The Tenth Fleet, 164-165.
37. Ibid., 174.
38. Packard, A Century of Naval Intelligence, 206.
39. Farago, The Tenth Fleet, 166-167. In naval parlance, a numbered fleet may be referred to with or without an article prefacing the number; that is to say, one sees “Tenth Fleet” and “the Tenth Fleet” used interchangeably. The term “Tenth Fleet” may also be used to refer specifically to the fleet commander.
40. Ibid., 7-8.
41. Ibid., 174.
42. Ibid., 164-165.
43. Ibid., 169-170.
44. Ibid., 200.
45. Ibid., 213.
46. Ibid., 214.
47. Packard, A Century of Naval Intelligence, 206.
48. Kahn, Seizing the Enigma, 243-244.
49. Farago, The Tenth Fleet, 170-171.
50. Daniel V. Gallery, Reminiscences of Rear Admiral Daniel V. Gallery, U.S. Navy (Retired) (Annapolis, MD: U.S. Naval Institute, June, 1976), March 5, 1971 interview, 74-76. Cited hereafter as Gallery, Reminiscences.
51. NARA, RG 457, Commander J.N. Wenger, USN, and others, Memorandum for Director of Naval Communications, Subj: History of the Bombe Project, April 24, 1944, 2; “Bombe History” folder; Historic Cryptographic Collection, pre-World War I through World War II. Cited hereafter as Wenger Bombe Memorandum.
52. Knowles telephone interview.
53. NARA, RG 457, Office of Naval Intelligence, OP-20-G, History of Communications Intelligence in the Battle of the Atlantic: Technical Intelligence from Allied C.I., n.d., 79; Document SRH 025; Studies on Cryptology, 1917-1977; Records of the National Security Agency/Central Security Service.
54. NARA, RG 457, Captain Laurance F. Safford, USN (Ret.), A Brief History of Communications Intelligence in the United States, 1952, 3; Document SRH 149; Studies on Cryptology, 1917-1977.
55. Kathleen Broome Williams, Secret Weapon: U.S. High-Frequency Direction Finding in the Battle of the Atlantic (Annapolis, MD: Naval Institute Press, 1996), 11.
56. David Syrett, ed., The Battle of the Atlantic and Signals Intelligence: U-Boat Situations and Trends, 1941-1945 (Brookfield, VT: Ashgate Publishing Company, 1998), xiii-xiv.
57. NARA, RG 457, Office of Naval Intelligence, OP-20-G, U.S. Navy Communication Intelligence Organization, Liaison and Collaboration 1941-1945, October 8, 1945, 19-20; Document SRH 197; Studies on Cryptology, 1917-1977. Cited hereafter as NARA, RG 457, COMINT Organization.
58. Williams, U.S. High-Frequency Direction Finding in the Battle of the Atlantic, 43.
59. Walter J. Boyne, Clash of Titans: World War II at Sea (New York: Simon and Schuster, 1995), 93.
60. Peter Padfield, Dönitz: The Last Führer (London: Cassell, 2001), 64-88. Padfield concluded it was Dönitz’s fault the boat was lost; Williams, U.S. High-Frequency Direction Finding in the Battle of the Atlantic, 9-10.
61. Intercept ZTPGU 26480, June 15, 1944: in DEFE3, Public Records Office, Kew. Quoted in Ralph Erskine, “U-Boats, Homing Signals, and HFDF,” Intelligence and National Security 2, no. 2 (April 1987), 327, ellipsis Erskine’s.
62. Williams, U.S. High-Frequency Direction Finding in the Battle of the Atlantic, 288.
63. Kahn, Seizing the Enigma, 4.
64. Ibid., 145.
65. Williams, U.S. High-Frequency Direction Finding in the Battle of the Atlantic, 120.
66. Ibid., 89.
67. Ibid., 13.
68. Williams, U.S. High-Frequency Direction Finding in the Battle of the Atlantic, 13; Safford, 3.
69. Williams, U.S. High-Frequency Direction Finding in the Battle of the Atlantic, 11.
70. Ibid., 94.
71. Ibid., 90; U.S. Coast Guard, Mendota (late—HMS Culver, Y-87), http://www.uscg.mil/hq/g-cp/history/mendota-1929.xhtml;, accessed January 8, 2004.
72. Williams, U.S. High-Frequency Direction Finding in the Battle of the Atlantic, 94-95; Boyne, Clash of Titans, 107.
73. Williams, U.S. High-Frequency Direction Finding in the Battle of the Atlantic, 147.
74. Clay Blair, The Hunted, 1942-1945, vol. 2 of Hitler’s U-Boat War (New York: Random House, 1998), 791-792.
75. Farago, The Tenth Fleet, 193.
76. Blair, The Hunted, 1942-1945, 792.
77. Williams, U.S. High-Frequency Direction Finding in the Battle of the Atlantic, 228.
78. William T. Y’Blood, Hunter-Killer: U.S. Escort Carriers in the Battle of the Atlantic (Annapolis, MD: Naval Institute Press, 1983), 282-283.
79. NARA, RG 457, COMINT History, 29.
80. Williams, U.S. High-Frequency Direction Finding in the Battle of the Atlantic, 208.
81. Boyne, Clash of Titans, 96.
82. Jennifer E. Wilcox, Solving the Enigma: History of the Cryptanalytic Bombe (Fort Meade, MD: Center for Cryptologic History, National Security Agency, January 2001), 1.
83. Kahn, Seizing the Enigma, 68.
84. Wladyslaw Kozaczuk, Enigma: How the German Machine Cipher Was Broken, and How It Was Read by the Allies in World War Two, ed. and trans. Christopher Kasparek (Frederick, MD: University Publications of America, 1984), 196-197.
85. Kahn, Seizing the Enigma, 222, 224-227.
86. NARA, RG 457, COMINT History, 22. The fourth enigma wheel was introduced at the worst possible time for Germany. Many aspects of the war at sea were changing, and neither Dönitz nor his staff noticed the sudden Allied blackout.
87. NARA, RG 457, COMINT History, 23.
88. Kahn, Seizing the Enigma, 53-55, 62-67.
89. Kozaczuk, 53.
90. Kahn, Seizing the Enigma, 73.
91. Ibid., 230-231.
92. Ibid., 106-112.
93. Ibid., 132-137.
94. Ibid., 116-118.
95. Ibid., 149.
96. Ibid., 179-182.
97. Ibid., 149, 179-182.
98. Wilcox, Solving the Enigma, 14.
99. Kahn, Seizing the Enigma, 161, 168-169.
100. Syrett, The Defeat of the German U-Boats, 20-21.
101. Blair, The Hunted, 1942-1945, 86-87; Kahn, Seizing the Enigma, 222, 224-227.
102. Blair, The Hunted, 1942-1945, 86-87.
103. NARA, RG 457, Wenger Bombe Memorandum, 5.
104. Kahn, Seizing the Enigma, 222, 224-227.
105. NARA, RG 457, Wenger Bombe Memorandum, 4.
106. Ibid., 5.
107. Ibid., 6.
108. NARA, RG 457, COMINT Organization, 38.
109. NARA, RG 457, Wenger Bombe Memorandum, 5.
110. Ibid., 6.
111. Ibid., 8-9.
112. Wilcox, Sharing the Burden, 9; NARA, RG 457, Wenger Bombe Memorandum, 8.
113. Wilcox, Sharing the Burden, 9, 27.
114. Ibid., 33.
115. Ibid., 29.
116. NARA, RG 457, Commander H.T. Engstrom, USNR, Memorandum for OP-20-G-1, Subj: Bombes - History of., March 24, 1944, 2; “Bombe History” folder; Historic Cryptographic Collection, pre-World War I through World War II.
117. NARA, RG 457, Wenger Bombe Memorandum, 8.
118. Ibid., 9.
119. Wilcox, Solving the Enigma, 32-33; Kahn, Seizing the Enigma, 239-240.
120. Wilcox, Solving the Enigma, 33-34.
121. Kahn, S
eizing the Enigma, 239-240.
122. Wilcox, Solving the Enigma, 35-36.
123. Ibid., 34-35.
124. Kahn, Seizing the Enigma, 241.
125. NARA, RG 457, COMINT History, 33; Y’Blood, Hunter-Killer, 282-283.
126. Packard, A Century of Naval Intelligence, 47, 124.
127. Zenon Lukosius, member of USS Pillsbury boarding party, interview with the author, December 9, 2001.
128. Packard, A Century of Naval Intelligence, 46. When U-85 was fatally damaged the order to abandon ship was given. Many crewmen made it out of the boat, which then slipped beneath the surface. Determined to make sure the boat was fatally damaged, Roper dropped eleven more depth charges over the spot, killing those men who had been fortunate enough to exit the boat. In addition to the petty officer’s notebook, many personal diaries were also recovered from the bodies. For more information, see Michael Gannon, Operation Drumbeat: The Dramatic True Story of Germany’s First U-boat Attacks along the American Coast in World War II (New York, NY: Harper and Row, 1990), 380-381.
129. Packard, A Century of Naval Intelligence, 125.
130. Ibid.
131. NARA, RG 38, Translations of Intercepted Enemy Radio Traffic and Misc. WWII Documentation; Translations of German intercepts U-boats (Messages) by Hull; U-475-U-508 box, message 0436/25/42 from U-505, March 25, 1944. Cited hereafter as NARA, RG 38, Intercepts.
132. NARA, RG 38, Records of the Naval Security Group Central Depository, Crane, Indiana; CNSG Library; folder “3270/409–CNSG–HFDF Operations–HFDF Logs for Atlantic Area, 1 Jan-31 Mar 1944;” log page for March 25, 1944. It was standing practice for U-boats to send a signal from 10 degrees West (later from 15 degrees West) to confirm the safe passage of the Bay of Biscay. From these messages British direction finders were able to determine the approximate latitude of each boat, and thus the boat’s probable destination.
133. NARA, RG 38, Intercepts, message 0436/25/42; NARA, RG 38, Records of the Naval Security Group Central Depository, Crane, Indiana, folder U-505 (Code Name “NEMO”)–Captured Documents: Navigational Charts and Materials, documents “Key to German Naval Grid” and “Mittel-und Südatlantik.” Cited hereafter as NARA, RG 38, Navigational Charts.
134. NARA, RG 38, Intercepts, message 1719/28/169/22 to Lange (U-505) and Wintermeyer (U-190), March 28, 1944; message 1251/29/306/179, March 29, 1944.
135. NARA, RG 38. Second message, see Office of Naval Intelligence, OP-20-GI-A, War Diary, Command “U-505,” Commanding Officer: Oblt.z S. Harald Lange, 7th War Cruise from 25 December 1943 to (4) June 1944; U-505 (Code Name “NEMO”); War Diary (Translated Version) folder, 15. Cited hereafter as NARA, RG 38, KTB.
136. NARA, RG 38, KTB, 15.
137. NARA, RG 38, KTB, 16; NARA, RG 38, Records of the Naval Security Group Central Depository, Crane, Indiana; CNSG Library; folder “3270/409–CNSG–HFDF Operations–HFDF Logs for Atlantic Area, 1Apr-31 Aug 1944;” log page for April 1, 1944. Cited hereafter as NARA, RG 38, HFDF Logs.
138. NARA, RG 38, Intercepts, message 0027/4/301 to Lange (U-505) and Schroeter (U-123), April 4, 1944.
139. NARA, RG 38, Intercepts, message 0121/5/317 to Lange (U-505) and Schroeter (U-123), April 5, 1944.
140. NARA, RG 38, Intercepts, message 1206/5/326 to Lange (U-505) and Schroeter (U-123), April 5, 1944; NARA, RG 38, KTB, 20.
141. NARA, RG 38, Intercepts, message 0449/10/394 from U-505, April 10, 1944.
142. NARA, RG 38, KTB, 21; NARA, RG 38, Intercepts, message 0914/10/396 to Lange IV (U-505), April 10, 1944.
143. NARA, RG 38, Intercepts, message 1253/13/340 to Rudolf (U-155?), Wintermeyer (U-190), and Lange (U-505), April 13, 1944.
144. NARA, RG 38, Records of the Naval Security Group Central Depository, Crane, Indiana; CNSG Library; Inactive Stations; Folder “B. (1): Daily Locations of U-Boats and Groups–30/10/43–1/6/44,” March 26, 1944, April 1, 1944, April 6, 1944, April 7, 1944, April 8, 1944, April 10, 1944, April 14, 1944. Cited hereafter as NARA, RG 38, Daily Locations. U-boats were identified by bigram rather than by hull number on the location lists. The bigram “BY” correlates to U-505 through the commanding officer’s name, the serial numbers of message traffic attached to BY, and the HF/DF fixes.
145. NARA, RG 38, KTB, 10; Naval Historical Center, Washington, DC; U.S. Navy; Translation of B.d.U. War Logs for period beginning January 1, 1944, ending June 30, 1944, entries for March 17 through April 14, 1944. Cited hereafter as Naval Historical Center, BdU War Logs.
146. NARA, RG 38, Intercepts, message 2302/14/3—from Lange IV (U-505), May 14, 1944.
147. NARA, RG 38, HFDF Logs, log entry for May 14, 1944; NARA, RG 38, KTB, 45; NARA, RG 38, Intercepts, message 0349/15/372 from BdU, May 15, 1944.
148. Naval Historical Center, BdU War Logs, May 14, 1944.
149. NARA, RG 38, Records of the Naval Security Group Central Depository, Crane, Indiana; CNSG Library; Intelligence Records of Inactive Naval Stations 1941-1945; folder “17 March 1944-19 May 1945;” COMINCH U-Boat Intelligence Summaries #50-80; U-Boat Intelligence Summary 52, April 28, 1944. Cited hereafter as NARA, RG 38, U-Boat Intelligence Summaries.
150. NARA, RG 38, U-Boat Intelligence Summaries, U-Boat Intelligence Summary 53, May 13, 1944.
151. NARA, RG 38, Daily Locations, May 15, 1944. As became his Commander’s rank, Knowles probably did not type up the daily location list himself. However, with rare exceptions the list bore a stylized “K” that Kenneth A. Knowles, Jr. has identified as his father’s mark (Knowles telephone interview).
152. NARA, RG 38, Records of the Naval Security Group Central Depository, Crane, Indiana; CNSG Library; Intelligence Records of Inactive Naval Stations 1941-1945; folder “COMINCH U-Boat Summaries, 1 Apr-30 Jun 1944;” message 151555, F-21 (Knowles) to CTF 60, CTF 62, CTF 63, CTF 66, CTG 22.11, CTG 22.16, CTG 22.2, CTG 22.3, CTG 41.6, May 15, 1944. Cited hereafter as NARA, RG 38, COMINCH Daily Estimates.
153. NARA, RG 38, Daily Locations, May 16, 1944.
154. NARA, RG 38, Daily Locations, May 17-20, 1944.
155. NARA, RG 38, Daily Locations, May 21, 1944; Naval Historical Center, BdU War Logs, May 21, 1944.
156. Gallery, Reminiscences, March 5, 1971 interview, 75-76.
157. Captain Henri H. Smith-Hutton, USN (Ret.), Reminiscences of Captain Henri Smith-Hutton, U.S. Navy (Retired), vol. 2 (Annapolis, MD: U.S. Naval Institute, August, 1976), August 22, 1974 interview, 402.
158. NARA, RG 38, Records Relating to Naval Activity During World War II; WWII Action and Operational Reports; TF 22.2 to TF 22.3; TF 22.3; folder “Task Group 22.3, Serial: 0021, June 19, 1944;” USS Guadalcanal; Report to Commander in Chief, Atlantic Fleet, subject: Report of A/S Cruise of Task Group 22.3, June 19, 1944, entry for May 13, 1944. Cited hereafter as NARA, RG 38, TG 22.3 Report.
159. NARA, RG 38, TG 22.3 Report, entries for May 14-15, 1944.
160. NARA, RG 38, TG 22.3 Report, entries for May 18-20, 1944.
161. NARA RG 38, TG 22.3 Report, entries for May 20-28, 1944.
162. NARA, RG 38, TG 22.3 Report, entry for May 28, 1944. U-505 was approximately 400 miles northeast of the task group at this time; the identity of this contact is unknown.
163. NARA, RG 38, COMINCH Daily Estimates, messages 181450, May 18, 1944; 191550, May 19, 1944; 201537, May 20, 1944, 211451, May 21, 1944.
164. NARA, RG 38, COMINCH Daily Estimates, message 231517, May 23, 1944; NARA, RG 38, Daily Locations, May 23, 1944.
165. NARA, RG 38, KTB, 53.
166. NARA, RG 38, U-Boat Intelligence Summaries, U-Boat Intelligence Summary 54, May 24, 1944.
167. NARA, RG 38, COMINCH Daily Estimates, message 281601, May 28, 1944.
168. NARA, RG 38, Daily Locations, May 28, 1944; NARA, RG 38, KTB, 56.
169. NARA, RG 38, Daily Locations, May 29, 1944, May 30, 1944, May 31, 1944, June 1, 1944; NARA, RG 38, COMINCH Daily Estimates, messages 291515, May 29, 1944; 301605, May 30, 1944; 311552, May 31, 1944; 011500, June 1, 1944.
170. NARA, RG 38, Daily Locations, May
22 - June 1, 1944; Naval Historical Center, BdU War Logs, May 22-June 1, 1944.
171. NARA, RG 38, Commander Task Group 22.3, Report to Commander in Chief, U.S. Atlantic Fleet, subject: Capture of German Submarine U-505, 19 June 1944; folder “Task Group 22.3, Serial: 0021, June 19, 1944;” TF 22.3; WWII Action and Operational Reports; TF 22.2 to TF 22.3; Records Relating to Naval Activity During World War II, 2. Cited hereafter as NARA, RG 38, CTG 22.3 to CINCLANT.
172. NARA, RG 38, TG 22.3 Report, entry for June 1, 1944; NARA, RG 38, KTB, 59.
173. NARA, RG 38, TG 22.3 Report, entry for June 2, 1944; NARA, RG 38, KTB, 59.
174. NARA, RG 38, TG 22.3 Report, entry for June 4, 1944. While the 0520 fix was on the opposite side of the task group from U-505, the 0629 bearing could have come from U-505. However, Lange mentioned no incoming or outgoing messages in the KTB for this date. NARA, RG 38, KTB, 60.
175. Gallery, Twenty Million Tons, 289-290.
176. Gallery, Twenty Million Tons, 292. For specific information about the Allied success against U-505, see Lawrence Paterson, “Collision Course: Task Group 22.3 and the Hunt for U-505,” and Jordan Vause, “Desperate Decisions that Doomed U-505,” both of which are reproduced elsewhere in this collection.
177. NARA, RG 313, Messages, message 062359, CTG 22.3 to CINCLANT, June 6, 1944.
178. NARA, RG 38, U-505 Documents, Wenger Exploitation Memorandum, 1
179. Ibid.
180. NARA, RG 38, Records of the Naval Security Group Central Depository, Crane, Indiana; CNSG Library; folder “CNSG–Enigma Machine–Information Regarding Captured Machines and Code Lists, 22 Jun 1944-19 Jun 1945;” memorandum from OP-20-G to F-21, June 22, 1944.
181. NARA, RG 38, U-505 Documents, Wenger Exploitation Memorandum, 2.
182. Ibid., 2-3.
183. Ibid., 3.
184. NARA, RG 38, U-505 Documents, memorandum from OP-20-GI-A for FX-01, October 21, 1944.
185. NARA, RG 457, COMINT History, 225-226.
186. NARA, RG 38, Messages, Memorandum for Distribution List Attached, serial 001786, June 18, 1944.
187. NARA, RG 38, Messages, message 141817, NOB BERMUDA to COMINCH, August 14, 1944.
188. NARA, RG 38, Messages, message 301957, August 31, 1944.
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