by John Keegan
By 1944, the U-boats were fighting a lost battle. Dönitz’s efforts to deploy boats capable of cruising undetected and at long range—the snorkel models, which could breathe submerged, and the Walther electro-boats, running on hydrogen peroxide, which did not need to breathe externally at all—were unsuccessful. The snorkel, hated by the crews for its tendency to burst their eardrums, so reduced the boat’s speed submerged as to negate its theoretical advantages, while the Walther boats were too shoddily built to achieve the results of which they should have been capable. After four years of war, and despite episodes of offensive success which had shaken governments on both sides of the Atlantic, the U-boats were a beaten force.
The pre-war elite, which had opened the campaign against Allied shipping, were dead or captured. Their successors, who had hit British shipping so hard in 1940–41, and had rampaged along the American coast in 1942, had suffered the same fate. There were few survivors of the great convoy battles of early 1943. The new commanders and new crews of 1944 paid a terrible price for their inexperience. Dönitz never relaxed his standards of training. Even so, U-boats remorselessly fell victim to the increasingly efficient British, Canadian and American escort groups and their associated air squadrons. Of the 591 U-boats which sailed between May 1943 and May 1945, 138 were sunk either in their first voyage or under a new captain, often within a few days of putting to sea. Of the seventeen U-boats which attempted to escape from Germany to Norway in May 1945, all but one newly commissioned, all were sunk.32
What had begun as an unequal struggle between an inadequate fleet of British escort ships, with primitive detection devices and crude underwater weapons, had swelled during the course of the war into a major anti-submarine campaign, prosecuted on the Allied side by an ever-larger armada of British, Canadian and American destroyers, sloops, frigates, corvettes and, critically, escort aircraft carriers, supported by an eventually very large complement of land-based aircraft. In the course of six years of bitter conflict, the Allies had introduced a succession of increasingly efficient detection devices and underwater weapons, including sonar able to register depth as well as bearing, centimetric radar and high-frequency direction-finding, a wide variety of depth charges, filled eventually with the very powerful Torpex explosive, and several models of forward-firing contact weapons, particularly Hedgehog and Squid. The Americans had also developed the deadly Mark 24 Mine (“Wandering Annie”), to be dropped from aircraft.
In response, the U-boat arm, though greatly expanded in number, from 57 in 1939 to a total of 1,153 built by May 1945, scarcely developed at all. The Types VII and IX, the former undersized, the latter unhandy, supplied most of its ocean-going strength throughout the war; their experimental successors were all unsatisfactory in one way or another. Their weapons, after early faults had been corrected, scarcely improved either; only the Zaunkönig acoustic torpedo was a real improvement, and by the time of its appearance the wolfpacks had been driven from the convoy routes. The U-boats’ passive detection devices—hydrophones, able to detect ship noises at long distance—were excellent, but no active detection device, such as centimetric radar, useful as it would have been despite its traceable emissions, was ever developed. The U-boats’ own radar-detection devices, such as Metox, were crude and came to be distrusted by their users. As a result, U-boat captains, like those of Nelson’s frigates, depended throughout the war on line of sight, enhanced only by forming patrol lines in exactly the same way as Nelson had done. Radio extended their range a little by providing a captain who got a sighting with means to summon others; but because of the danger of interception, and the relatively low superiority of speed of a surfaced U-boat over that of a convoy, patrol lines had to be kept quite short. As Dönitz was frequently to comment, even the best-placed patrol line, operating against convoys controlled by a headquarters that could steer them away from identified U-boat traps, was often intercepted by boats only at the extremity, leaving the rest to make up hundreds of miles of sea room before they could achieve an attacking position. Long-range aircraft, which might have found convoys at a greater distance than a U-boat captain could see from his conning tower, were in even shorter supply on the German than the Allied side; and the German Condors not only lacked the range of the B-24 Liberator, the dominant aircraft of the Atlantic battle, but were based exclusively in France, and thus limited in coverage, while their Allied equivalents flew from Northern Ireland, Cornwall, Iceland and North America and so were eventually able, with the introduction of Very Long Range models, to oversee the whole Atlantic.
THE INTELLIGENCE BALANCE
The Allies—the British and Canadians first, the Americans later—enjoyed superior tactical intelligence throughout the Atlantic battle. They had sonar (Asdic) from the start, HF/DF and centimetric radar from 1942, aerial surveillance—of expanding range—from 1939. There were serious lapses, associated with shortages of escorts in 1939–41 and with American refusal to form convoys in the first six months of 1942. Nevertheless, while tactical intelligence collected by the U-boats was limited by a patrol line’s line of vision, supplemented eventually and only close to France by that of the Condor aircraft, the convoy escorts and their associated patrol aircraft always had the edge, which increased throughout the war. Eventually the Allies’ tactical advantage became overwhelming.
The question of the importance of intelligence in the Atlantic battle therefore turns on the strategic issue: B-dienst versus Bletchley. The B-dienst was a remarkable organisation. Working largely with human resources, rather than the electromechanical devices later available in England and the United States, the German decoders—their target was the Naval Cypher No. 3, a book code mathematically super-enciphered—achieved impressive success for several long periods. Having broken the old (Royal) Naval Code, a system of five-digit groups, as early as 1935, it used the clues the Code provided to attack the newer Naval Cypher and by April 1940 were reading as much as 30 per cent of British transmissions. The Naval Cypher and Code were replaced, however, in August 1940 by new versions of each, against which the B-dienst had less success. It recovered its form when Naval Cypher No. 3 was introduced in June 1941 for transatlantic communication, and read it throughout 1942; in December it was reading 80 per cent of messages sent. Between 15 December, when the British added precautions, and February 1943, it was again in the dark but then found a way back, “sometimes reading directives to convoys ten and twenty hours before the movements they ordered took place.” Not until June, when an entirely new cipher was distributed, were British signals at last made secure.33
On their side, the British, and later the Americans of OP-20-G in Washington, experienced similar periods of light and dark. The British benefited from a series of captures during 1940 and 1941—of U-33 in February 1940, of the patrol boat VP2623 in April and, in March 1941, of the trawler Krebs during the commando raid on the Norwegian Lofoten islands. In May and June the weather ships München and Larenburg were seized in deliberate “cutting out” operations, while on 9 May, U-110 fell into British hands. Each yielded some material—either parts of the Enigma machine, or gridded charts, or enciphering material—which, when added to what Bletchley had been able to reconstruct from interceptions, furthered decryption. Traffic for February, May, June and July 1941 was read in part or whole, as a result, and some in real time. After August 1941 until February 1942, the Heimisch key, called Dolphin at Bletchley, was read at a delay of not more than thirty-six hours. The decryption was considerably assisted by the deployment of the first bombes, which greatly assisted in the identification of possible Enigma key settings. Much help was also provided by the carelessness of German operators in retransmitting Enigma messages previously enciphered in the dockyard (Werft) or weather ciphers, which were quite easily read.34
After February 1942, however, Bletchley lost its way into the U-boat traffic because of the German adoption of a new Enigma key, called Shark by the British, Triton by the Germans, on the first of the month. Regular reading in real
time did not resume again until December 1942. This period coincided with the reciprocal B-dienst success against British naval ciphers and with a peak of German advantage in the Battle of the Atlantic. In June (129), July (136) and August (117), monthly sinkings exceeded one hundred ships. Total sinkings exceeded four million tons.35
Paradoxically, however, during what historians of the U-boat war denote as “the great convoy battles” in the first five months of 1943, the British were frequently reading Enigma in real time and the Trade Division was redirecting some convoys away from U-boat patrol lines. Moreover, although there were massacres, U-boat losses were also rising, eventually to unbearable levels, forcing Dönitz, in May 1943, to take his boats out of the North Atlantic and so, effectively, admit defeat.
What, therefore, are we to make of F. H. Hinsley’s assertion that Bletchley achieved one of its undeniable successes in the Atlantic battle? Hinsley, a Bletchley veteran, is notably modest in the claims he makes for the British Government Code and Cipher School. He specifically rejects the view that “Bletchley won the war,” and rightly so. His estimate of Bletchley’s success in the war against the U-boats must be set, however, against Clay Blair’s sober and heavily documented assessment that over 99 per cent of all ships forming transatlantic convoys reached their destinations safely. Out of 43,526 ships sailed (many several times, of course), 272 were sunk by U-boats. Many others were sunk but usually when sailing independently or having left convoys, either to “straggle” (fall behind) or to “romp” (sail ahead).
Allied merchant seamen paid a terrible price. Over 30,000 out of 120,000 in the British Merchant Navy alone were killed in the struggle against the U-boats. The U-boat crews, however, suffered worse: 28,000, out of an enlisted force of 40,000, died in the destruction of their submarines—which amounted to 713. Aircraft sank 204, warships 240, aircraft flying from escort carriers 39; ships and aircraft operating together sank 84; mines, accidents and other incidents—such as U-boats ramming each other—made up the difference in numbers.36
The outcome of the Atlantic battle, seen in perspective, suggests that intelligence, as in so many other operational circumstances, was, though significant, secondary to the age-old business of fighting the issue out. In easy times, as during the U-boats’ Happy Time along the eastern American seaboard in the first six months of 1942, it was not strategic intelligence but day-to-day happenstance that yielded the victims. In the more difficult times, particularly during the “great convoy battles” of early 1943, Bletchley’s ability to steer convoys out of danger frustrated many of the traps Dönitz laid, but it was the stolid endurance of the merchant seamen, sticking to convoy commodores’ orders, and the dogged determination of the escort crews to fight back, that did the U-boats in. Modern interpretations of the Battle of the Atlantic represent it as a true battle, in which one side attacked, the other accepted the challenge to defend or counterattack, and counterattack prevailed. That seems correct. The Battle of the Atlantic could have been won without the assistance of the codebreakers, greatly though they helped to tip the balance in the favour of the defenders.
CHAPTER EIGHT
Human Intelligence and Secret Weapons
THE SECRET AGENT dominates popular conceptions of the intelligence world, how it works and what it yields. The image of the agent is strongly imprinted on the imagination of anyone who in childhood played the war game l’Attaque—a sinister civilian figure parting the grasses to spy on brightly uniformed soldiers honourably and conspicuously engaged in combat—and that image has been reinforced for over a century by the work of successful fiction writers. Joseph Conrad made the agent an enemy of society, Conan Doyle, in “The Bruce-Partington Plans,” a venal creature working for money; but most writers in English represented the agent as romantic and patriotic: Kipling’s Kim a servant of empire in the Great Game, John Buchan’s Richard Hannay bursting with Britishness in pursuit of his country’s enemies, Sapper’s Bulldog Drummond to whom all foreigners were objects of suspicion. Later writers, John le Carré foremost, refined the image, admitting the dubiety of the agent’s role and introducing the idea of the double agent, all too understandably in view of what the public then knew of treason among Britain’s university-educated class.
The idea nevertheless persisted that “intelligence” was principally the “product”—a term popularised by le Carré—of spying. The idea survived the disclosure of the Enigma secret, which revealed that the most valuable intelligence produced by the British intelligence services during the Second World War was derived from the interception and decryption of enciphered enemy signals. That was equally true of British intelligence successes during the First World War and of the American intelligence effort in 1942–45. British and American fiction readers were by then too enamoured of the idea of the “agent in place,” however, to alter their view of the essential nature of the craft. The spy, not the eavesdropper, was established in the popular imagination as the principal source of knowledge of the enemy and his evil intentions.
The popular imagination entirely overlooked the limitations within which real agents laboured. The danger of betrayal was recognised, and that of identification by enemy counter-espionage. What was discounted was the much more oppressive burden of practicality: how to discover anything worth knowing; how, even more critically, to communicate such knowledge to the home base. Memoirs by agents of the Special Operations Executive (SOE), Britain’s subversive organisation inside German-occupied Europe in 1940–45, and of OSS, the contemporary American Office of Strategic Services, reveal a picture quite at variance with that of the glamour and romance depicted by writers of fiction. SOE and OSS operatives dealt in tiny scraps of information, often of apparently trivial importance—gossip picked up in cafés, numbers of freight cars seen crossing a bridge, shoulder straps of soldiers glimpsed changing station. Such scraps, when collated, had to be recorded in comprehensible form and then sent by radio transmitter, whose operators always knew that they risked being overheard by enemy interceptors with location devices and so of being intercepted and arrested in mid-transmission.
There was little that was romantic about spying in Hitler’s Europe. The business was furtive, nail-biting and burdened by the suspicion of betrayal. Many agents were betrayed. The German counter-espionage service was extremely efficient at identifying networks, breaking their members and inducing those arrested to inform against their fellow conspirators. Women proved better than men at keeping out of German clutches, because of their superior ability to remain inconspicuous and to deflect difficult questions. Many women nevertheless fell victim to the Gestapo. Men in the networks were arrested in large numbers. Their fate, that of women and men alike, was despatch to Hitler’s camps.
GERMAN SECRET WEAPONS
There were gaps, nevertheless, in the Gestapo system, particularly in its ability to protect the German secret weapons programme. Because the testing of Germany’s pilotless weapons, later to be known to the British as the V-1 and V-2, necessitated test flights over areas populated by non-Germans in the Baltic and Poland, and because Germany’s acute shortage of labour forced the organisers of the secret weapons programme to employ non-German labour in work, particularly construction work, at the secret weapon sites, information leaked out. Over time, eyewitness reports, transmitted through networks run particularly by Poles, would yield considerable amounts of information about German secret weapon development. It was not, however, information for which the British were particularly looking at the outset. Under threat of invasion after June 1940 and heavy air attack after September, they were more concerned about the dangers of the here and now rather than those that might lie in the future.
As early as February 1939, however, seven months before the outbreak of war, the Committee for the Scientific Survey of Air Defence, chaired by the distinguished scientist Sir Henry Tizard, had decided to form an intelligence section and a young physicist, Dr. R. V. Jones, had been appointed to lead it. He was first directed to collect
information about bacterial and chemical weapons, then believed to be a serious menace. In October his attention was diverted elsewhere, if only briefly. A report was received of an experimental station, located on the Baltic coast between Danzig and Königsberg in East Prussia, where the Germans were testing a “rocket shell” carrying 320 pounds of Ekracite explosive over ranges up to 300 miles.1 The source lay in gossip and might therefore have been discounted, along with much other rumour about fantasy devices. On 4 November, however, another report arrived on Dr. Jones’ desk, sent by the British naval attaché in Oslo, the capital of Norway.
About 2,000 words in length, “the Oslo Report,” as it became known, was not rumour but a detailed communication, obviously written by a practising scientist, describing nine weapons or weapon systems under development in Germany. Some were conventional—a new bomber, an aircraft carrier—some were not; the report also identified sites at which the new weapons were being tested. Among the unconventional weapons mentioned were a remote-controlled anti-ship glider bomb, a pilotless aircraft, “remote-controlled shells” propelled by rocket, acoustic torpedoes and an anti-aircraft proximity fuse. One of the two test sites named was at Peenemünde on the Baltic coast.2
The origin of the Oslo Report was mysterious and remained so for many years. Recently, however, it has been suggested—the suggestion has not been universally accepted—that the author was a German scientist, Hans Friederich Meyer, director of research at the great German electrical company Siemens.3 Meyer, who opposed Hitler’s racial policies, had a British friend, Cobden Turner, of the British General Electric Company. Much troubled by the treatment of a half-Jewish child whose mother he knew, Meyer told Turner of the case and Turner, equally troubled, managed to obtain a visa for the girl to leave Germany for England from the head of the MI6 station at the British embassy in Berlin, Frank Foley, just before war broke out. Foley was then posted to Oslo but Turner induced Meyer, as a token of gratitude for the grant of the visa, to write what we now know as the Oslo Report. Meyer typed it up on a visit to Oslo on official business on 1–2 November 1939 and it reached R.V. Jones, without attribution, two days later.