Seizing the Enigma (55 page)

231
“main cipher method”: M.Dv.Nr.32/3 (1941), 2.

231
“Equipping with the Enigma”: PG 47006:Bericht über den Nachrichtendienst am 4.3.41.

231
Navy monitored, required reports: PG 34455F:i9.Januar 1939, 28.November 1939; MA:M797/47357:50–51, 8. Mai 1941; Kleikamp, 15; PG 47364:26. Mai 1941 and 29.April 1941.

232
Prien,
Graf Spee:
RM 7/103:36, 41.

239
5 October 1941: Erskine, “Naval Enigma: Breaking of Heimisch and Triton,” 180.

239
U-570: ADM 199/2058:38. BdU, KTB, 5 November 1941, on the surrender of the U-570, has nothing about ciphers.

240
Desk IVa: Kahn,
Codebreakers
, 456, 458.

241
“despite great stresses”: PG 32137:186.

244
rise in traffic volume: Rohwer, “Ultra and the Battle of the Atlantic,” 429, 432.

244
January 1, 1943: Rohwer and Jäckel, 125.

245
February 1, 1942: Hinsley, 2:179.

248
sixty times better, “unimaginable”: RM 7/121:60.

249
recover the wiring of the 4th rotor: Hinsley, 2:747.

249
cryptanalysts apprehensive: Wylie interview.

249
“the picture”: Hinsley, 2:230.

250
considerable knowledge: Beesly, 111–12.

250
14,000 per month: Hinsley, 2:29.

250
radio fingerprinting,
TINA
: Hinsley, 1:271.

250
“working fiction”: Beesly, 113.

250
direction-finding: Mitchell interview.

252
three
TRITON
keys: Hinsley, 2:228.

252
one of ten, one of three: Rohwer, “Ultra and the Battle of the Atlantic,” 432, 435.

252
600,000, 2,600,000: Roskill,
War at Sea
, 1:618, 2:486.

252
seventeen days: Hinsley, 2:228.

252
fears grew: Hinsley, 2:168–69, 548.

253
“a little more,” “the one campaign”: Hinsley, 2:548.

Details of the U-559, its cruises, and its captain are from PG 30594; Rohwer,
Axis Submarine Successes;
NA:RG i65:G-2 Captured Personnel and Material Branch: Enemy POW Interrogation File (NIS-Y): German Prisoners at Byron Hot Springs: Albert Müller, 23881. Details of the
Petard
, its captain and crew, and the attack on the U-559 are from ADM 199/2060:44–45; ADM 1/14526; Connell, passim, esp. 65–71; Thornton (unpublished), passim. In a letter of October 8, 1989, Connell wrote that he and several other members of the crew of the
Petard
to whom he has shown this file agreed that some statements in it, made several weeks or months after the sinking of the U-559, confuse this incident with the similar boarding of the Italian submarine
Uarsciek.
The
Petard
came alongside the
Uarsciek
but stayed perhaps a hundred yards away from the U-559.1 have therefore eliminated from my account all references to the U-559’s closing with the
Petard.

255
U-boats to Mediterranean: Dönitz, 158, 199; Germany, Oberkommando der Kriegsmarine,
Lagevorträge
, 409.

255
“decisive area”: Ibid., 302.

265
“It’s out”: Wylie interview.

265
“It’s come out”: Monroe interview.

265
four-letter indicators: Hinsley, 2:750.

265
Beesly thrilled: Beesly,
Very Special Intelligence
, 152.

265
position of fifteen U-boats: DEFE 3:705:ZTPGU 1; Erskine, “Naval Enigma: The Breaking of Heimisch and Triton,” 120.

266
sinkings halved: Roskill,
War at Sea
, 2:486.

Details about interception and direction-finding come from Mitchell interview. Information about the Bletchley bombes is from interviews with Herd, Milner-Barry, Monroe, and Stewart; Payne, 9–16; “Breaking Enigma”; Hinsley, 1:338, 2:748, 750; Welchman,
Hut Six Story
, 141, 144, 147. Details about Hut 8 and cribs are from interviews with Wylie, Amys, and Hinsley; Deavours and Krüh, “Turing Bombe.” Information about the Hut 4 watches are from interviews with Forster, Ettinghausen, and Eytan.

The background to the British-American exchange of cryptanalytic information may be found in Hall and Wrigley, 358–63, 375–81; Hinsley, 2:55; Ronald W. Clark,
Tizard
(Cambridge, Mass.: M.I.T. Press, 1965), 248–71. Cryptanalysis
is specifically mentioned in NA:RG 165: War Plans Division 4340: September 9, 1940. The story of the trip of the four American cryptanalysts comes from Rosen interview; Currier, untitled memoir; Weeks letter; SRH-145, 002–004; ADM 199/447:Operation Parcel; ADM 53/114501 January 24–February 6, 1941.

The operation of the American naval cryptanalysis and its cooperation with the British come from interviews with Joseph Eachus, W. V. Quine and Marjorie Quine, Prendergrass, McMahan, and Bartelmez; Hinsley, 2:56; Beesly,
Very Special Intelligence
, 108–10; “U.S. Navy Communication Intelligence Organization Liaison and Collaboration 1941–1945,” SRH 197 (October 8, 1945), reprinted in
NCVA
[Naval Cryptologie Veterans Association]
Cryptolog
5 (Winter 1984), 5–11.

275
U.S. Army contingent: Parrish, 106.

275
6812th, two to three times as many solutions, U-boat cipher: Stewart interview.

277
20 percent, 3 percent: Safford, 12.

277
exchanging direction-finding: Safford, 4.

278
former girls’ school: “Rochefort Affair: Admiral Stone Comments,”
NCVA Cryptolog
6 (Fall 1984), 6.

279
“The Star of Suez”: SRMN-032,001.

280
high-speed bombes; Atha, 332–36.

283
daily U-boat summary: W. V. Quine interview.

283
naval Enigma read to end of war: Hinsley, 2:751–52, 552. The date of May 24, 1943, at 2:667 should be May 24, 1945 (Hinsley).

284
solutions to Knowles: Knowles, 445.

284
Secret Room: SRMN-038.

285
“were not as smart”: Smith-Hutton,
396–97.

285
Convoy & Routing chart: Norgaard interview.

Information on the convoy’s composition, escorts, and routing is from U.S. Navy, Naval Historical Center, Operational Archives, Tenth Fleet Files, Convoy & Routing Section, Convoy Folder SC 127, and from ADM 199/580, supplemented by National Archives of Canada, Record Group 24, Vol. 11335, File C-8280, SC 127. All Allied estimates of submarine locations come from SRMN-033. All U.S. solutions of German naval messages come from SRGN. All information about German intelligence and activity comes from BdU, KTB, under the appropriate dates. Weather conditions are from the log of H.C.M.S.
Dundas.

Food and shipping problems are from Behrens, 201, 312, 328, 331, 334, 342, 345–46; Hammond, 1:261–68, 2:792; Great Britain, Ministry of Food,
How Britain Was Fed in War Time
, 58–59.

287
April 16 sailing details: National Archives of Canada, Record Group 24, vols. 12015, 12042.

287
92, 111, 29, 50, 95: Morison, 1:410.

290
three days behind: DEFE 3.

290
U.S. report for April 16: SRMN-033:2074.

290
Operational Research: Blackett; Waddington; Schofield, 161.

291
63 boats operating: BdU, KTB, April 16, 1943.

293
grid bigrams: comparison of SRGN 15945 and DEFE 3:716:131, in which the British message gives the enciphered coordinates and the American message the solved ones.

294
no messages solved for Monday: SRGN 16029 is a message of April 18, SRGN 16030 is a message of April 20.

294
“Since this position”: BdU, KTB, April 18, 1943.

295
Katyn, a German Dunkirk, white hair: [Germany], Reichssicherheitshauptamt, Amt III,
Meldungen aus dem Reich
, ed. Heinz Boberach (Neuwied: Luchterhand, 1965), Nr. 377.

295
In the United States:
New York Times
, April 21, 1943.

300
HX234: Hinsley, 2:568.

303
“We can no longer rely”: Hinsley, 2:563.

303
5 to 10 percent: Rohwer, “Einfluss,” 359.

303
“In the Atlantic”: BdU, KTB, May 24, 1943.

304
no convoys: Hessler, §301.

304
April 18: BdU, KTB, April 18, 1943.

304
Maertens exculpated Enigma: RM 7/107.

305
regional key nets; RM 7/108:44; BdU, KTB, February 3, 1943.

305
new type of radar: Reuter, 113–14.

305
“With the exception” BdU, KTB, March 5, 1943.

306
“the enemy has”: BdU, KTB, April 27, 1943.

306
“For some time”: BdU, KTB, April 27, 1943.

306
Maertens, Stummel: Walter Lohmann and Hans H. Hildebrand,
Die Deutsche Kriegsmarine 1939–1945: Gliederung, Einsatz, Stellenbesetzung
(Bad Neuheim: Podzun, 1956), 3:320, 386.

306
“had, on the basis”: MA: III M 1006/4:147.

306
telling the Japanese ambassador: NA:RG 457: Diplomatic “Magic” Summaries: 24 September 1943:2.

306
basic cryptosecurity principle: MA: III M 1006/4:147.

308
Naval Cypher No. 5: Hinsley, 2:636–38.

308
“The two main”: MA: III M 1006/6:169.

309
Adressbuch:
Hinsley, 2:552, 681–82.

309
less than half avoided: Hinsley, 2:555.

Information on the attacks on the U-66 and U-117 comes from U.S. Navy, Naval Historical Center, Operational Archives, World War II Action Report, Commander in Chief, U.S. Atlantic Fleet, Hunter-Killer Operations, Serial 001020, Report Nos. 1–43 and 2–43, Task Group 21.14. Other details come from SRGN; SRMN-033; PG 30063; BdU, KTB; the deck log of the U.S.S.
Card;
and Lundeberg.

311
“milch cows”: Werner Rahn, “Weiträumige deutsche U-Boot-Operationen 1942/43 und ihre logistische Unterstützung durch U-Tanker,” unpublished paper.

312
adamant refusal: Hinsley, 3:1:212–13.

312
“we should not risk”: Hinsley, 2:549.

313
“if our Z information”: Hinsley, 2:549.

313
U-118: Y’Blood, 55–59.

Calculations of the value of codebreaking are from SRH 368 and Rohwer, “Einfluss,” 359–61.

Allason, Rupert [Nigel West].
The Sigint Secrets: The Signals Intelligence War, 1900 to Today, Including the Persecution of Gordon Welchman.
New York: Morrow, 1988.

Andrew, Christopher. “F. H. Hinsley and the Cambridge Moles: Two Patterns of Intelligence Recruitment.” In
Diplomacy and Intelligence During the Second World War: Essays in Honour of F. H. Hinsley
, ed. Richard Langhorne, pp. 22–40. Cambridge: Cambridge University Press, 1985.

——.
Secret Service: The Making of the British Intelligence Community.
London: Heinemann, 1985.

Andrew, Christopher, and Jeremy Noakes, eds.
Intelligence and International Relations 1900–1945.
Exeter Studies in History, 15. Exeter: University of Exeter, 1987.

Arnold, Philip M. “A German Code Book.”
Cryptologia
3 (October 1979), 243–45.

Atha, Robert I. “Bombe! I Could Hardly Believe It!”
Cryptologia
9 (October 1985), 332–36.

Bauer, [Hermann].
Das Unterseeboot: Seine Bedeutung als Teil eine Flotte—Seine Stellung im Völkerrecht—Seine Kriegsverwendung—Seine Zukunft.
Berlin: Mittler & Sohn, 1931.

Beesly, Patrick. “Das Operational Intelligence Centre der britischen Admiralität und die Schlacht im Atlantik.” In Rohwer and Jäckel, pp. 133–47.

——.
Room 40: British Naval Intelligence 1914–18.
London: Hamish Hamilton, 1982.

——. “Special Intelligence and the Battle of the Atlantic: The British View.” In Love, ed., pp. 413–19.

——.
Very Special Admiral: The Life of Admiral J. H. Godfrey, CB.
London: Hamish Hamilton, 1980.

——.
Very Special Intelligence: The Story of the Admirality’s Operational Intelligence Centre, 1939–1945.
London: Hamish Hamilton, 1971.

——. “Who Was the Third Man at Pyry?”
Cryptologia
11 (April 1987), 78–80.

Behrens, Catherine] B. A.
Merchant Shipping and the Demands of War.
History of the Second World War: United Kingdom Civil Series. London: Her Majesty’s Stationery Office, 1955.