In fact, the Germans had also developed radar, and earlier than Watson-Watt. They called it Dezimator Telegraphie, or DeTe for short. Dr Rudolf Kühnold, Chief of the Kriegsmarine Signals Research Department, had been working on bouncing underwater sound waves – which became sonar – when it occurred to him that the same principles could be applied to radio waves above ground. This he developed into a radar that could be used for ship detection and gun ranging, either from land or from a moving ship. A prototype was developed which could change its range and accuracy by altering the frequency it used. This became known as ‘Freya’, and its shorter-range version, which was fitted to surface ships, was called ‘Seetakt’.
‘Freya’ and ‘Seetakt’ had been made by the Gema company, but in the meantime Telefunken, a rival company, had developed a small, mobile radar capable of plotting aircraft up to twenty-five miles away. The ‘Würzburg’, as it was called, was highly sophisticated, mechanically rotated and elevated, and capable of guiding both anti-aircraft gunners and fighters on to targets. And since it was rotational, it could operate on a 360-degree setting and on land.
Thus when the Germans thought of other countries developing radar, they assumed they would be small, rotational, sophisticated pieces of kit like the ones they were developing, and not huge rows of iron lattice towers staring out from the cliffs for all the world to see. And spot them they did. German ‘tourists’ were packed off to Britain to go ‘sightseeing’ around Bawdsey, and then in May 1939 General Wolfgang Martini, head of the Luftwaffe signal organization, persuaded Milch to allow him to fly over one of the old Zeppelin airships to have a look. The airship, he believed, with its ability to drift slowly and presenting a large object, would be perfect to try and find out whether these masts were indeed some kind of primitive British radar, or something quite different altogether. The Zeppelin duly went over, approaching Bawdsey then turning north and heading along the east coast. Expecting to hear some kind of response from their radio receivers, the crew were surprised to hear nothing but a loud continuous crackling sound. What they were hearing was high-frequency static, but because they had already discounted high frequency for radar – they were using very-high-frequency (VHF) and ultra-high-frequency (UHF) ranges – it did not occur to them that they were in fact picking up beams from a radar network.
The Zeppelin had been picked up immediately by one CH station after another, its course plotted and tracked carefully. Going into cloud, it actually drifted over Hull, well into British airspace, but despite the temptation to send a radio signal telling them so, those charting its movement decided to keep shtum. Soon after, the Zeppelin turned for home, with General Martini none the wiser. Convinced there must have been some kind of technical defect with the airship’s own kit, Martini sent it over again. In August, in bad weather, the Zeppelin came over a second time. This time, however, it picked up nothing at all, not even static. By sheer fluke, the radar chain had been turned off that day to sort out some minor malfunction.
Less than a month later, war broke out and any further investigations into the strange high towers dotted along the British coast were put on hold. This did not unduly concern Martini, however, or any of the Luftwaffe High Command. Because of their size, shape and use of high frequency, the masts had been discounted as being radar. Unwittingly, the crude, rather ungainly appearance of these monster masts had worked very much in Britain’s favour.
Just to put the seal on it, they discovered a British mobile radar set that had been abandoned near Boulogne. Although rather like the German ‘Freya’, this was even more rudimentary. Instead of being impressed by their find, the Germans who examined it were delighted to discover the British had such crude pieces of kit and were operating a DeTe set so technologically behind their own.
Now, as they looked across the Channel to the high masts perched above the white cliffs of Dover, they still had no clear idea what these pylons were for. Soon enough, though, once they were over England, they would find out.
27
Trouble at Sea: Part 1
‘TOMORROW AT DAWN, we put into operation a plan called CATAPULT,’ jotted Jock Colville on 2 July, ‘which entails the seizure of all French ships in British ports, and, later in the day, an ultimatum to the big French capital ships at Oran.’ Concern about the French Fleet had been mounting in London. The Kriegsmarine on its own might not have been a match for the Royal Navy; the German and the Italian fleets together made a formidable enemy; but the German, Italian and French fleets could prove potentially disastrous. By the original terms of the armistice, the French Fleet was to assemble at French ports under German and Italian control, but Admiral Darlan, the French C-in-C, decided to send the bulk of the Fleet to its base at Mers-el-Kébir, near Oran, in French Algeria. The Germans did not object to this.
The British did, however. Both the British and Général de Gaulle made a plea for all French ships and forces to continue to fight and, in the case of the French navy, head for British ports. Some did, including two old battleships, several destroyers and a number of submarines. There were also several capital ships at Alexandria. These refused to join the British, so were immediately demobilized under British instructions.
Both Darlan and Marshal Pétain insisted that no warship would be allowed to fall into German or Italian hands, but however honourable may have been their intentions, Vichy France was now a German vassal state and their ability to enforce such a declaration was limited to say the least. From the British perspective, the risk of those ships being turned over to the enemy was simply too great. On 28 June, the Cabinet came to a difficult, but unanimous conclusion. The French Fleet at Oran and Algiers must surrender to the British or be attacked and destroyed. ‘This was a hateful decision,’ noted Churchill, ‘the most unnatural and painful in which I have ever been concerned.’
The man given the job of confronting the French Fleet was Admiral James Somerville, now commander of the powerful Force H, hastily sent to guard the Western Mediterranean in the absence of the French. Somerville, like many in the Royal Navy, knew a number of his French counterparts well; indeed, many were friends. ‘You are charged with one of the most disagreeable and difficult tasks that a British Admiral has ever been faced with,’ came the message from the Admiralty, ‘but we have complete confidence in you and rely on you to carry it out relentlessly.’ In the early hours of 2 July, Somerville sent his ultimatum, which despite repeated appeals and negotiations was rejected. Thus, at 5.54 p.m. on 3 July, Somerville’s ships opened fire. One French battleship blew up, another ran aground and a further battleship was beached. One cruiser escaped to Toulon, albeit damaged, as did those at Algiers. A few days later, the huge battleship Richelieu, at Dakar, was also put out of action. Over 1,200 French sailors, who just a couple of weeks before had been allies and comrades in arms, lost their lives.
When Churchill told Parliament what had been done, tears had streamed down his cheeks. On 5 July, Vichy France formally broke off relations with Britain. The sinking of the French Fleet at Mers-el-Kébir was a tragedy, but had, in a stroke, eliminated a serious threat. More than that, it showed the world that Britain had no intention of rolling over.
Group Captain Tommy Elmhirst and his colleagues on the Joint Intelligence Sub-Committee had been busy trying to collate and interpret intelligence regarding Germany’s intentions. On 4 July, they submitted their latest appreciation, concluding that Germany was indeed preparing an invasion. There were reports of large-scale landing exercises, troop-carrying aircraft had been moved from training schools to front-line duties, aerial photographs suggested large numbers of rafts were being built at Kiel; dive-bombing units were being concentrated in Holland and north-east France. So it went on – a long list of compelling evidence that suggested invasion was imminent, although ‘unlikely to take place before the middle of July’.
Meanwhile, General Ironside, C-in-C Home Forces, had been putting together his own plan for the defence of Britain, which included more anti-invasion
obstacles, anti-tank obstacles, and a ‘crust’ of troops protecting the coast with mobile reserves inland. ‘In general, I find myself in agreement with the Commander-in-Chief ’s plan,’ noted Churchill, then added, ‘Until the Air Force is worn down by prolonged air fighting and destruction of aircraft supply, the power of the Navy remains decisive against any serious invasion.’
In this he was correct, but already a major strategy dispute had broken out between the Admiralty and Admiral Forbes, the C-in-C of the Home Fleet. Admiral Pound, the First Sea Lord, was determined that not only should imminent invasion be taken extremely seriously, but enough ships should be available to mount a crippling attack on an invasion force before it even set sail. To achieve this, he ordered that a strike force of four destroyer flotillas – some thirty-six ships – with cruiser support should be kept along the east and south-east coasts, all within the Nore Command.
This was overly cautious. As Dunkirk had proved, ships could be moved from bases as far north as Scapa Flow to the Channel within twenty-four hours, whilst even those out in the Western Approaches would be able to get there within a couple of days. For Admiral Sir Charles Forbes, it was a ridiculous suggestion. The 59-year-old veteran of Gallipoli and Jutland was a hugely experienced sailor who had commanded destroyer flotillas and battle squadrons, held senior staff positions at the Admiralty and with the Mediterranean and Atlantic Fleets, before being made C-in-C Home Fleet in 1938. Modest and unassuming, with a dry sense of humour, he was enormously popular with those who served under him. He was utterly imperturbable, never known to be rattled, and his calm, pragmatic mind was able to work through a number of myriad difficulties, whilst always maintaining a very clear sense of proportion. Charming and possessed of sound judgement he may have been, yet Forbes was not a man afraid to speak his mind, nor to stand up to his superiors if he believed they were wrong.
And he certainly believed Pound was wrong over the disposition of the Fleet. While others in London were awed by the German successes on the Continent, Forbes, from his cabin aboard HMS Nelson at Scapa Flow, was able to stand back and view matters slightly more logically. To him, an imminent invasion seemed unlikely. Germany had not yet won air superiority, which he considered a prerequisite for invasion, nor did the Germans appear to have anything like the number of surface vessels for such an operation. British experience in Norway showed how hard it was to transport and maintain a force without control of the air. Of course, he argued, it was always possible the Germans might be foolish enough to mount an invasion anyway. ‘If so,’ he wrote to Pound, ‘we should welcome the attempt as being an excellent opportunity to inflict a defeat on the enemy, but we should not deflect our forces and energies into purely defensive measures to guard against it.’ This was the nub of the matter. The Home Fleet did not have enough ships to both keep vigil in the Channel and adequately protect convoys as they drew towards the Western Approaches. Forbes believed that it made far more sense for the Germans to try and sever the transatlantic lifelines than attempt an invasion. In any case, he was certain that until the RAF had been destroyed, no invasion attempt could possibly be made without Britain knowing about it at least twenty-four hours earlier, thanks to radio intercepts and aerial reconnaissance of Continental ports. Should such an attempt be spotted, ships could hurry to the Channel in time. In the meantime, he believed his forces were far better used protecting convoys from U-boats and sweeping for mines.
Pound, however, was having none of it. Despite the calm logic of Forbes’s arguments, the First Sea Lord declared them unconvincing. ‘The JIC have appreciated that the enemy has plenty of military forces available for invasion,’ he noted tersely, ‘in addition to his other commitments.’
Even Pound, however, must have been troubled by the staggering numbers of ships that were now being sunk. Every week the Chiefs of Staff and Cabinet were presented with a list of shipping that had been lost; it made for sobering digestion. In the last week of June, for example, so much shipping had been sent to the bottom of the sea, it could no longer fit on the graph summaries that were produced by the Naval Intelligence Department. From 288,461 tons of shipping lost in May, the figure had risen to 585,496 tons in June. Since the beginning of the war, nearly 1.5 million tons of new shipping had been built but nearly 2.1 million tons had been sunk. At current rates, that discrepancy would soon rise to critical proportions. Strangling British sea-lines had suddenly become a very real possibility – particularly if the German U-boat force continued to grow.
When the then Kapitän Karl Dönitz had been appointed commander of the Kriegsmarine’s submarine force in 1935, he had been disappointed by the post. A naval agreement had just been signed between Britain and Germany, in which Germany had suggested limiting her naval strength to 35 per cent of that of Britain. It was a clever move, because it tested whether Britain was prepared to move away from the Versailles Treaty, whilst suggesting that Germany had no hostile intentions towards her. At the same time, because of the large size of the Royal Navy, 35 per cent still enabled Germany to build two large battle cruisers, the Gneisau and Scharnhorst, and the giant battleships Bismarck and Tirpitz. On the matter of submarines, Germany agreed a 45 per cent parity with Britain and promised to abide by the 1930 London Treaty Submarine Protocol, which barred unrestricted submarine warfare against merchant shipping. The agreement was a coup for Hitler. From having had a navy of just 15,000 men, Germany was now allowed to build a considerable force with the blessing of the world’s largest naval power. It was British appeasement at its worst.
From Dönitz’s perspective, however, the agreement showed that the Kriegsmarine’s future lay in surface vessels, so for an ambitious 48-year-old, his new command seemed something of a dead-end. However, he had been a U-boat commander in the last war and, having thrown himself into his new job, became convinced that not only would Germany one day be at war with Britain, but that when such a time came to pass, submarines, not capital ships, would be the key to German naval success. In his view, U-boats had come very close to winning the war for them in 1914–18, and had they built more of them rather than battleships, the end result could have been very different. Submarines had come a long way since then. They were tougher and faster, could dive quicker – the Mk VII could dive in about thirty seconds – and had larger, more numerous torpedoes, warheads that were battery-powered and wakeless, thus making them harder to detect, and with ranges of up to three miles. Radio technology had also improved. The new U-boats were equipped with highly effective long- and short-wave transmitters and receivers. This meant that U-boats could not only communicate with their base but also with one another. Now, Dönitz realized, U-boats could operate together, and hunt for enemy shipping as a pack – a wolfpack as he called it. And while it was true that more advanced anti-shipping weapons, such as sonar, had been developed, Dönitz believed they were overrated – a threat, yes, but not a considerable one.
He made little headway in persuading Admiral Raeder, commander of the Kriegsmarine, the OKM, or the OKM staff, that U-boats were the way forward, however. Not only were they already committed to the existing building programme, they did not want to risk, at this stage, breaking the Anglo-German agreement. Furthermore, unlike Dönitz, they believed that modern technology and improvements in aircraft range and power put submarines at a severe disadvantage.
Following Munich and the instigation of the massive rearmament drive, the OKM produced the Z Plan, which although it called for 233 U-boats also proposed building six battleships, eight cruisers, four aircraft carriers and a number of surface vessels. The U-boats and battleships were to be completed by 1943, which was still five years away. The Z Plan was flawed for many reasons, but it missed an important truth. Germany’s geography, with only a stretch of coastline in the narrow Baltic, made it very difficult for surface vessels, particularly large capital ships, to break out into the Atlantic, where any war on Britain’s lifeline would have to be conducted. The English Channel was impassable in a time of war owing to
mines, aircraft and British shipping, but the route into the North Sea and around the north of Scotland was also easy for the British to block. The only vessels that could adequately reach the hunting grounds of the Atlantic were U-boats. The Royal Navy had large fleets of surface vessels but their role was primarily to protect those lifelines, for which fast, powerfully armed surface vessels were well-suited. Germany’s task would be to destroy as much merchant shipping as possible – and for that, Dönitz believed, U-boats were the best tool available. Furthermore, there was another massive advantage. Unlike battleships or aircraft carriers, U-boats were comparatively easy, quick and cheap to build. Lots of them could be produced in a comparatively short time. And they used less fuel.
By the summer of 1939, Dönitz was ever more convinced that the Germans would soon be at war with Britain. Germany had already publicly renounced the Anglo-German Naval Treaty and the hurried rearmament programme had been instigated because of the threat in the west, rather than the east. Britain had made its pledge to Poland. With war thus looking increasingly likely, Dönitz asked Admiral Raeder to convey to Hitler his continuing concerns about the size of his U-boat fleet, which had only twenty-seven ocean-going boats, of which just nineteen were ready for war. In contrast, Britain had fifty submarines and France, seventy. In July, Raeder conveyed Hitler’s reply. ‘He would ensure that in no circumstances would war with Britain come about,’ noted Dönitz. ‘For that would mean finis Germaniae. The officers of the U-boat arm had no cause to worry.’
Why Hitler was so anxious to keep his navy in the dark is not clear, but with the subsequent outbreak of war seven weeks later he soon began to recognize the important role U-boats could play, a role already outlined in some detail in a paper earlier submitted by Dönitz. Thus, in September, Hitler scrapped the Z Plan and ordered the beginning of a massive U-boat Command, with the emphasis on the Mk VIIs that Dönitz had been urging for several years. Indeed, such was the urgent importance of now building U-boats, they were to take priority over even key projects such as the Ju 88, while skilled shipwrights drafted into the Wehrmacht were to be sent back to the shipyards right away. Hitler wanted Britain out of the war and he now believed that the U-boats were the key to achieving this, more so than Göring’s much-vaunted Luftwaffe. The new plan called for the production of U-boats at a rate of thirty to forty a month. Dönitz, it seemed, had been right all along, and, as if to prove the point, six weeks after the outbreak of war one of his U-boats made an emphatic statement of intent, with the sinking of just one boat. Not any old boat, however, but one of Britain’s mighty 50,000-ton battleships: HMS Royal Oak.
The Battle of Britain Page 41