Case YELLOW
IN THE WAR at sea, the Royal Navy had scored some valuable points but had received a number of bloody noses too; it was nothing that Britain couldn’t take on the chin, but two attacks in particular had been more than just a little humiliating for the country that prided itself on and set great store by its naval supremacy. The first had occurred in September when the aircraft carrier Courageous had been sunk by a U-boat off Ireland. At the time, Courageous had been U-boat hunting with only a small screen of destroyers. The sinking of such a valuable asset showed that U-boat hunting was not the right role for such large and important capital ships – it was a lesson learned the hard way.
The second setback had been a carefully planned attack on the British Home Fleet at Scapa Flow, their base on the Orkney Islands north of Scotland. The Fleet had already been out on several aggressive sweeps across the North Sea, hunting German surface vessels, but it was German submarines that once again were to prove the thorn in their side. Scapa Flow, while providing a good anchorage, had been neglected in terms of defences, and Admiral Forbes, commander of the Home Fleet, had been ordered to move to a safer base at Loch Ewe on the west coast of Scotland. However, in early October, the German battle cruiser Gneisenau, and several other Kriegsmarine surface ships, had been reported as venturing into the North Sea, so Forbes’s main force was sent to intercept them north-east of the Shetlands. The German ships beat a hasty retreat, but on the night of 13–14 October, several capital ships from the Home Fleet were still back at Scapa, and with the Northern Lights flickering across the sky, a single U-boat, U-47, captained by the imperturbable Günther Prien, managed to slip into the narrow passage and successfully sink the battleship Royal Oak, with the loss of 833 men. It was a severe shock not just to the Navy, but to Britain as a whole.
It was also a PR coup Germany milked for all it was worth. Prien became an overnight pin-up in Germany; if there was one area in which Germans felt a palpable inferiority complex it was over their Navy. That Prien had shown such daring, cunning and skill by successfully slipping into the lion’s den and slaying one of the beasts showed what could be done. No one was more pleased than Admiral Dönitz, for while there was no immediate increase in U-boat production as a result, the sinking of the Royal Oak showed Hitler that a single, relatively inexpensive, vessel manned by fewer than fifty men could destroy a huge battleship crewed by 1,200. It demonstrated what might be achieved with a U-boat fleet of the kind of numbers Dönitz had been suggesting.
The British were, naturally enough, defiant and no one more so than the First Lord, Winston Churchill. On 8 November, he gave a speech to the House of Commons on the loss of the Royal Oak. Listening from the gallery was Jock Colville, who, since the outbreak of war, had left the Foreign Office after being asked if he would like to join No. 10 as one of the Prime Minister’s secretaries. He’d been assured of very long hours and plenty of tedium too, but the chance to be close to the centre of things was an opportunity he was unwilling to let slip. Now, at the House of Commons, he thought Churchill was acquitting himself well, particularly when it came to rubbishing German bragging. ‘When I recall the absurd claims which they are accustomed to shout around the world,’ Churchill told the House, ‘I cannot resist saying we should be quite content to engage the entire German Navy, using only the vessels which at one time or another they have declared they have destroyed.’ That, Colville thought, was his best point. ‘The latest German claim,’ Colville noted later, ‘is to have sunk HMS Kestrel, which turns out to be a naval sea-plane base some miles inland.’
Bragging aside, the Kriegsmarine had not had it all its own way in any case. Three U-boats from the tiny total force were sunk in October, and in December the pocket battleship Graf Spee had been chased to the River Plate in Argentina. Before this, the Graf Spee had been cruising British trade routes on the hunt for merchant shipping. It had sunk three merchantmen before being tracked down by a British hunting group of two heavy and two light cruisers. Having been blockaded in the mouth of the River Plate, the ship’s captain had been ordered by Berlin to scuttle her rather than let her fall into British hands. Just as the Germans had milked the sinking of the Courageous and the Royal Oak especially, so the British made much of the so-called Battle of the River Plate. A month later, in January, the Graf Spee’s supply ship, the Altmark, was caught near Trondheim in Norway on its return from the South Atlantic. The ship was boarded by sailors from the destroyer HMS Cossack, and found to be armed and holding 299 prisoners, who were released.
This was, in fact, an infringement of Norwegian waters and neutrality. ‘The wireless has just given the first news of the boarding of the Altmark,’ wrote Vere Wight-Boycott, whose ship had recently returned to Britain and was now part of the Home Fleet. ‘Cossack seems to have done some fine work.’ He did wonder, though, what the American reaction might be to this violation of neutrality. As it happened, not a lot; the US was already showing double standards on such matters. At any rate, already Admiral Carls’s emphasis on attacking Allied shipping with a fast cruiser force was beginning to look a little misjudged. It is impossible to know what would have happened had the U-boat force been some 200 or even 300 strong in the opening months of the war, but there is no question that with that number, with well-trained crews, and before the Royal Navy had really organized its measures for anti-submarine warfare (ASW), Germany’s chances of bringing Britain swiftly to heel would have been far higher. The sea lanes were Britain’s lifeline. Without them, it would have been paralysed. And since much of Britain’s overseas shipping passed through the Atlantic, whether it was coming from the Americas or the Far East, the Atlantic battleground should have been Germany’s top priority in the war against Britain. Hitler, and the Wehrmacht command, however, were continentalists. The entreaties of enlightened men like Admiral Dönitz were given scant regard.
As it was, nine of the small number of U-boats had been lost by the end of 1939. U-48, however, was not one of them. Rather, under Kapitänleutnant Schultze, the submarine had continued to sink Allied ships, so that by the New Year the crew had no fewer than twelve to their name, and the 1WO, Teddy Suhren, had been promoted to Oberleutnant zur See. But as January gave way to February, Suhren and his comrades noticed the war was becoming harder; the Allies had started arming merchant vessels, and shot at anything that looked like a sub. The convoy system, too, was harder to penetrate, and the escorts more numerous. The weather was a factor as well. That first winter of war was terrible, and Suhren wondered whether, somehow, war and catastrophe could influence weather patterns. The Kiel Canal froze over, while out at sea their oilskins would become caked in ice while they were on the bridge. Drops of water froze and remained hanging from eyelids and beards, while inside the U-48, everything remained continually damp, with condensation glistening on the bulkheads, breath hanging in the air like fog, and food moulding.
As if the weather weren’t enough, the U-boat crews had to contend with the enormous risks of their wartime profession. For merchant vessels, the word U-boat conjured up images of a dark, sleek and stealthy killer – and as a ship destroyer it was certainly highly effective. Yet for the crews, bottled up in a damp, stinking, foetid tin can, it was an unbelievably tough and threatening existence, in which hunter could become hunted at any moment. If hit, the crew faced drowning or suffocation, which was a long, lingering and awful death. They knew the chances were they would never be found, that wives, lovers and family would be left wondering what had happened to them. Such matters did not bear thinking about, and yet sometimes it was hard not to. Oberleutnant Suhren had lost a good friend when U-41 was sunk on 5 February by a British destroyer off the coast of Ireland. The two U-boats had been alongside one another at Heligoland before that patrol, and Suhren had seen his old friend Jürgen, an officer on U-41. Jürgen had seemed downcast – his brother, a pilot in the Luftwaffe, had been killed, and now he was convinced he was for the chop too. ‘He was absolutely right,’ noted Suhren. ‘There were no survivors . . .’
Suhren was lucky not to end up permanently at the bottom of the sea himself. For a submariner, there can have been few things more unsettling than being repeatedly depth-charged. These were explosive devices that were set to sink to a certain level and then explode. For those under attack, there was the constant fear of knowing that at any moment an explosion might come that could seal the fate of the sub and all within it.
On 14 February, they were positioned off the south-west coast of Ireland, over towards St George’s and the Bristol Channel. It was early morning, with a heavy fog, when suddenly out of the mist loomed the outlines of ships. A large convoy was heading straight for them.
‘Kapitän, on the bridge! Alarm! Crew to action stations,’ came the cry, and with Schultze hurrying back down the conning tower, they hastily dived with a roar and sank to periscope depth. Everyone on board now had a specific role to play. Zurn, the LI, or Chief Engineering Officer, set the trim of the U-boat, i.e. tried to keep it steady on an even keel and depth. Schultze himself was still in the conning tower at his station on the periscope, which he lowered, then lifted up again, put the right pedal down and swung it a full 360 degrees. Directly below, in the control room, Suhren waited, listening, ready to pass on Schultze’s orders. In an attack, it was the captain who made every decision about when to fire, when to dive, what depth, what speed. At the bow of the U-boat, the caps of the torpedo tubes were opened. At the TDC, the torpedo-attack computer, the No. 1 sat and waited, listening carefully to what Schultze told him. This device fed information into the torpedo tubes – it worked through adjustors that were air-drive gyros; as the torpedo was fired, the gyros started up and steered the missile in the right direction.
Quiet descended through the boat. All that could be heard was the low hum of the electric motors as the submarine travelled slow-ahead.
‘OK, Chief?’ asked Suhren, sticking his head up through the open hatch.
Schultze nodded. ‘We’re standing well off to port. In five minutes I’ll be ready to shoot.’
‘Much in the way of escorts?’
Schultze nodded again. ‘Enough.’
Five minutes passed, with everyone on board concentrating on their station. No one spoke. Then Schultze raised the periscope once more and looked around. Instructions were passed down, trim and course adjusted, then he called out, ‘Tubes one to four, stand by!’ followed by, ‘Tube one – fire! Tube two – fire! Three – fire! Four – fire!’
After that, what felt like a long wait. The target was 1,800 metres away, and the torpedoes travelled at thirty knots. That meant around 120 seconds – two whole minutes. The stopwatch ticked. The LI was struggling to keep the U-boat at periscope depth and asked for more speed.
‘Eighty seconds,’ called out the Obersteuermann. Then 90, 100, 110.
Schultze ordered the boat be turned to starboard, then a dull thud – a hit! They had just struck the SS Sultan Star, a large 11,300-ton British freighter filled with meat from the Argentine.
‘Quick, go deep!’ ordered the captain.
‘What’s up?’ asked Suhren.
‘An escort’s spotted us. She’s coming straight for us!’
Everything now happened at once. Two more explosions – their torpedoes had hit the ship twice more – but, even then, the submarine was rapidly diving, creaking and groaning as it did so as the pressure around it increased. At 120 metres down, a fusilade of eight depth charges erupted, and in frightening proximity. U-48 lurched and rolled. Above them, they could clearly hear the enemy ASDIC, the ship’s onboard sonar, ping-ping-ping, and the low whirr of the propellers. The submarine was now effectively pinned down, and there was damage already.
‘Exhaust valves making water!’ came a report from the engine room.
‘Zurn,’ said Schultze, ‘make sure the valves are closed down as far as they’ll go.’
Zurn did so, but they were still taking on a small amount of water.
Above, the convoy continued on its way – Suhren, who had taken the hydrophones from the radio operator, could hear the engines, but then the sound of the escorts’ propellers drowned it out – it sounded like a nail being scraped across a plate. It was 0700. More depth charges, bubbling down towards them. He handed back the headphones and braced himself. An explosion, the boat rocked, then five more in quick succession. But they were still in one piece. Calmly, Schultze ordered a change of course west.
That was not the end of the attacks, however. The U-boat dropped to 120 metres. The explosions seemed to be getting closer. They dived further, the hull creaking and grinding until, with a bump, they stopped at 135 metres – the charts put them at the Cockburn Bank. It was as deep as they could go. Above them, a destroyer was raking over them once more, the ping of the ASDIC still quite audible. The whirr of the propeller, followed by gurgling bubbles as the depth charges fell, then peng-wham! Peng-wham! Peng-wham! Once more U-48 rolled and shook and was tossed off the seabed and thumped back down again. ‘We can scarcely stay on our feet,’ noted Suhren. ‘We look for a handhold and hang on wherever we can.’
Inside, no one dared speak; they barely dared breathe. A bit of metal fell on the deckplate, prompting angry glares towards the man responsible. Another hour passed, then another, each marked by a further attack. By noon, they had been pummelled with depth charges no fewer than eleven times. Suhren had made some calculations – the hydrophones had picked up the smack of the depth charges as they hit the water; they sank at 4 metres per second and the explosions occurred after twenty-eight seconds – that meant they were detonating at between 110 and 120 metres; just 15 metres above them.
‘What do you think?’ Schultze asked Suhren. ‘Should we leak out a bit of oil? Then they’d be sure to think they’d hit us.’
‘No,’ replied Suhren, shaking his head. ‘No movement at all. Just play dead. Once it gets dark, they’ll knock it off.’
They all looked tense, strained and drawn. Only Schultze appeared to be as calm and imperturbable as ever; imperturbability was one of the key attributes for any submarine captain.
Down in the U-boat, it was neither daylight nor night, but up above, on the ocean’s surface, darkness had fallen. But every half-hour, more depth charges burst around them; there was no let-up. The hissing sound of the ventilator began to grate on the crew’s nerves, but there was nothing they could do about it. ‘We wonder,’ noted Suhren, ‘whether we would have had so much patience, or whether we’d already have reported “enemy destroyed”. Gradually my doubts return. How long can an execution take?’
Hours passed, slowly, painfully, the tension never lessening for those inside the U-boat. Then at 2200, a flurry of eight depth charges, not five. Was that significant? Maybe – yes.
‘Listening Room, what can you hear?’ asked Suhren.
‘Herr Oberleutnant, I can hear the two destroyers getting further away!’
But Schultze was not moving just yet. Another half-hour – just to be safe.
The half-hour passed – and still no sound from above, so Schultze ordered the pumps to start, which they did with high-pitched humming Suhren found hard to bear as they battled against 13.5 atmospheres of pressure. Slowly, slowly, the vessel lost weight and gradually, gingerly, lifted off the seabed. They were now going forward, climbing gently until finally, at long last, they broke the surface. Suhren followed Schultze up on to the bridge. As they opened the hatch and clambered out, Suhren could feel his eardrums throb with the equalizing of pressure. To their horror, they saw bright lights all around them – they were encircled by about twenty fishing boats at anchor on the Cockburn Bank. But it was night and nothing was stirring, so half submerging and relying on their electric motors, they quietly slipped away, undetected.
They were barely clear of the fishing boats when new shadows loomed up ahead as they closed in on more merchant shipping. Once more, Schultze ordered them to attack, aiming for a large freighter. Torpedoes were fired and after a hundred seconds came an explosion – another ship gone, added to U-48’s mounting tally.
‘There you are, Suhren,’ said Schultze. ‘Attacking again and getting a hit are the best medicine.’
That February, there were never more than ten operational U-boats at sea, but fifty-six Allied merchant ships were sunk, along with three U-boats. There could be no doubting that the war at sea was now well underway. In contrast, nothing much was stirring on the ground – nor in the air for that matter. The appalling weather put paid to that.
This did not mean there was a lack of activity, however. Rather, factories from England to German-occupied Poland and Czechoslovakia continued to build more tanks, aircraft, munitions and other instruments of war. At parade grounds and training camps, men drilled and learned the rudiments of soldiering, while along the Western Front the opposing sides readied themselves, prepared defences, drilled for the clash that suddenly seemed as though it might never happen at all.
At Zossen, the OKH continued to do their level best to prevent any imminent assault in the West while at the same time putting together a plan of attack that might have some chance of success, however slim. But in the ten weeks between von Brauchitsch’s dressing-down by Hitler at the beginning of November and the first couple of weeks of the New Year, General Halder was not making a huge amount of progress.
There were, however, a couple of senior commanders within the Army who thought they might have found a way. One was General Erich von Manstein, who was Chief of Staff of Armeegruppe A, one of three groups of armies already assembled, and who, during that time, had produced and sent to Halder no fewer than seven drafts of a daring plan in which the main thrust was a surprise attack through the Ardennes. The idea was that a sizeable thrust would be made in the north, through Holland and into Belgium. The Allies would assume this was the main attack and would then move their troops forward, through Belgium, to meet this thrust. At the same time, however, the real main attack would go through the thick forest and rolling hills of the Ardennes in south-west Belgium. The invading force would emerge and cross the River Meuse, the main French line of defence, and then drive straight towards the Channel coast. The vast bulk of the French, Belgian and British armies would then be caught in a massive encirclement. That was the plan: a two-pronged attack, one a feint in the north, where the Allies most expected it, and the other the main attack, or Schwerpunkt, where it was least expected.
The Ardennes was an area of thick forest, rolling hills and steep river valleys that ran across the south-west part of Belgium, which, as in 1914, was firmly neutral. In truth, each draft was much the same and was based on the premise that if the Germans could reach the mighty River Meuse and cross it in a surprise operation, a rapid thrust using what mechanized troops they did have could blaze through France before the slow, more methodical enemy army had a chance to react.
Halder, however, had dismissed von Manstein’s suggestions, for while his basic idea was certainly bold and daring, it was, to his mind, dependent on far too many variables for comfort: that the extremely complicated logistic operation through the Ardennes – an area widely considered impassable to large-scale mechanized troop movements – would go to plan; that Allied air forces would not detect it; that the French would be surprised; that the French would not be able to recover sufficiently; that untested panzer units could cut such a swathe across France. After all, by the spring – the most obvious time in which to launch an offensive – there would be just ten panzer divisions and six mechanized divisions in the entire Army. Could those few really be expected to sweep through France in the way that von Manstein was envisioning? Halder wasn’t convinced by any stretch of the imagination, but he was also keenly aware that it was precisely the kind of daring and outrageous plan that Hitler would immediately latch on to. Furthermore, Hitler had even suggested a thrust across the Meuse at Sedan on the edge of the Ardennes himself, not through any genius of military thinking, but rather because it was there that the Prussians had successfully crossed in 1870. With this in mind, Halder therefore put von Manstein’s memos to one side.
In the New Year, however, two events happened that made Halder think again and dramatically reconsider the possible merits of von Manstein’s plan. The first took place on 10 January, when a German aircraft made a forced landing near Mechelen in Belgium. On board was a Luftwaffe operations officer with copies of the latest German offensive plans, which still held that a thrust through the Low Countries was to be the main point of attack. Realizing how important the documents were, the German officers hastily tried to burn them. They were captured, however, before the plans had been destroyed. What had been a terrible security leak had suddenly become a stunning opportunity for deception, despite Hitler’s ire, because the incident prompted a rapid response from the Allies, who began extensive troop movements, going on to the alert all along the front and moving reserves forward, all of which was watched and noted by Luftwaffe reconnaissance planes. It showed that the Allies had been expecting a German attack exactly as outlined in Halder’s current plans.
The second event happened a few weeks later. At the end of January, von Manstein had been sidelined and given command of a corps that existed in name only. Frustrated by this, Generals Günther Blumentritt and Henning von Tresckow, two admirers of von Manstein, took it upon themselves to give von Manstein’s plans to General Schmundt, Hitler’s military aide. They were then shown to Hitler, who, of course, embraced them immediately.
The situation by mid-February, however, was very different to the one back in October. It was true the Allies were by then out-producing Germany in terms of aircraft and tanks, but the months of uneasy calm along the Western Front had been of considerable help to the Wehrmacht too. In that time, ammunition stocks, which had fallen so drastically low during the Polish campaign, had been replenished and increased, and, more importantly, valuable lessons had been learned and incorporated into training. Poland had been a crucial test-run. While France and Britain had been holding the line and building defences, the German Army had been preparing for offensive operations, now with experience to throw into the mix. Numbers of new aircraft were certainly well below what Göring and the Luftwaffe wanted, and only a few new U-boats were entering the war on shipping, but the Army was in immeasurably better shape than it had been just a few months earlier.
Another factor that helped change Halder’s stance had been the slow French response to recent German regrouping movements along the front: intelligence suggested they had taken as much as two weeks to realize there had been a change in German troop dispositions. Thus if it should prove possible to move enough forces through the Ardennes forest of Luxembourg and Belgium and reach the main French defences in less time than that, it would, theoretically, be possible to catch them out. ‘Surprise may now be regarded as assured,’ he noted with confidence in his diary after a February Führer conference. What’s more, any thrust through the Ardennes would have a far better chance of success if it was done in good weather and when the days were long, with plenty of sunlight. Fortunately for Halder, bad weather had meant continual postponements of Hitler’s proposed assault. This too was playing into Halder’s plans to ensure the Army was sufficiently ready for an operation of this magnitude before being committed.
Furthermore, Hitler was now beginning to think of striking at Denmark and Norway first, before an assault on France and the Low Countries. The winter’s armaments drive had shown just how much iron ore was needed by Germany. The trouble was, most of it came from Sweden via Norway, so securing its safe passage away from the British Navy was essential. Invasion and occupation were the only way to guarantee this. Moreover, Norway would provide important bases for future attacks on British shipping. All in all, such an attack offered a number of benefits, and especially before any strike in the West.
So now, in February 1940, Halder was faced with better conditions for an offensive, the chance to make the most of an unintentional deception plan, and the opportunity to secure a northern flank and crucial iron ore first. Finally, war games at the beginning of February had also shown this daring plan of attack might just – just – work after all. What Halder had gradually realized through the first two months of 1940 was that they faced a stark choice: a more cautious plan that would avoid any quick defeat, or a go-for-broke gamble that risked everything but which also offered the only realistic chance of decisive victory.
Thus by the end of February, when Halder submitted his latest plans, he had completed his dramatic volte-face: Armeegruppe B would noisily thrust into Holland and northern Belgium with the support of the majority of the Luftwaffe, while the panzers of Armeegruppe A would hurry through the Ardennes and attack the French across the Meuse. With luck, the Allies would be coaxed into a trap, rushing forward to meet the northern thrust, while the main German attack burst through the back door around Sedan, ensnaring the bulk of the Allies’ northern front in a huge encirclement before they had time to effectively respond. The operation was to be codenamed Fall Gelb – Case YELLOW: a codename, like Case WHITE, that was neutral and deliberately bland.
The trouble was, though, that while Halder and even von Brauchitsch were now convinced their plan was the right one, it was all too clear that most of the senior commanders in the Wehrmacht did not agree. And even for Halder there was no doubt that Case YELLOW was a massive, massive gamble. There was still much that could go wrong.