The Night the Dams Burst Read online

  Another recruit was Tony Burcher, a rear gunner. Guy Gibson rang up Mickey Martin and asked if he would like to return to squadron duties – there was a special do on. “I understand, by the way, that Tony Burcher is over there with you. Bring him back as a gunner.” When Burcher got to No. 617’s mess he found John “Hoppy” Hopgood there. “Hoppy” had been his flight commander too, at No. 106. Burcher wrote in a letter: “I had assumed that I might be going back to fly with Mickey, but his two air gunners from his previous tour were there so obviously they flew with him and I attached myself with John's aircrew.”

  Gibson told them only that they were to practise low-level flying in three formations, that it was left to them what height they considered to be safe, and then, with a chuckle, that they were to consider 150 feet to be their maximum altitude. That was no picnic. A Lancaster's altimeter was known to be “pretty dicey” in those days.

  He did not reveal to them for some weeks what they were going to be attacking – indeed, he himself did not even know yet. Late in April his men were told obliquely that that their target would be over water and they were to practice flying over lakes. His men assumed that the target would be Hitler's U-boat pens or battleships like Scharnhorst, Gneisenau, and even Tirpitz.

  “At that time,” recalled Shannon, “none of us, apart from Gibson, Leggo [Flight Lieutenant J F Leggo, RAAF], Hay [Flight Lieutenant R C Hay, RAAF], Trev [Flight Lieutenant R A D Trevor-Roper, RAFVR] and other section leaders were in the know. So we went and practised low flying over various lakes and reservoirs.”

  INTENSIVE TRAINING began, and soon complaints about low-level flying were cascading into the Bomber Group's headquarters. One angry local mayor said that he had seen motorists actually duck as formations of black-painted four-engined Lancasters thundered past only 150 feet up. Legend has it that Group HQ wrote back: “Our pilots have now been instructed to show due regard for other road-users… ”

  Late on April 6, 1943, the first special Lancaster was delivered to Farnborough; its mid-upper gun-turret had been removed, and unusual modifications had been made to the bomb bay. Now the first “Upkeep” bomb was clamped into position between the callipers, and the hydraulic motor coupled up to test the bomb's spin. That evening Wallis telephoned the RAF's new Controller of Research and Development, and told him that every-thing was “Okay.”

  All was ready for the Lancaster to begin the first dropping trials. “We'll try the first drop at about 270 m.p.h.,” Wallis told the pilot, Sam Brown, “giving the bomb a back spin of about three hundred revs. Let it go when you are level, at 150 feet.”

  In confident mood, Barnes Wallis waited behind the little ruined church on the shore at Reculver on the north Kent coast, watching for the Lancaster. Wing Commander Gibson drove up shortly and joined him, both of them shivering in the cold morning wind.

  Soon they heard the familiar full-throated roar of Lancaster engines in fine pitch. Brown, a civilian test pilot for A V Roe, the plane's manufacturer, was at the controls. Dead on time the big bomber appeared out of the low early-morning sun, followed by another Lancaster, slightly higher, carrying a cine-camera to record its progress. The first Lancaster had the bulky Dams Bomb suspended beneath it – the first that had ever been tested.

  As the Lancasters neared the white marker-buoys a hundred yards off shore, Wallis began to shout, hopelessly, into the roar of engines, “Sam, Sam, you're too high. You're too high!”

  Gibson trained a pair of binoculars onto the bomb itself, chequered black and white and already spinning backwards at great speed. He had never seen anything like it. He wondered what on earth could be the target for such a remarkable device. He saw the bomb slowly detach itself from the Lancaster. “It seemed to hang in the air for a long time before it hit the water with a terrific splash,” he wrote.

  A plume of water sprang up out of the sea, missing the Lancaster by inches. But instead of bouncing, the bomb lurched briefly out of the boiling cauldron of spray, then sank without trace.

  After lunch, a second bomb was dropped, with the bomber much lower than before; this time, the bomb suddenly disintegrated in a shower of wooden staves, steel bands and bolts, the heavy steel cylinder bursting out with such violence that one wooden segment smashed into the Lancaster's tail just above it, and nearly brought the aircraft down.

  Sunk deep in thought, Wallis trudged with Gibson back through the shingle to where their cars were parked.

  CHAPTER TWO: In which Mr Barnes Wallis gets the special bomb to work, and the raid begins

  BRITISH INVENTOR-EXTRAORDINARY Barnes Wallis shivered as the sea slowly rose to his neck. I'm getting beyond this sort of thing, he thought.

  He and a handful of middle-aged men dressed only in underpants were slowly edging their way out from the beach. Had anybody else been strolling down that deserted Reculver shore in Kent that chilly April evening, it would have been a strange sight that met his eyes.

  But there were no onlookers. It was wartime. This was April 17, 1943, and all access roads to this secluded spot had been cordoned off by sentries all day.

  Wallis was one of the foremost aeronautical engineers in Britain. The other bathers were leading scientists and civil servants.

  “It's no use,” sighed Wallis after a while. “We've been looking for hours. The fragments must all be buried far too deep. Let's go back to the Miramar for dinner – I'm getting cold.”

  They were looking for the remains of a ball that they had lost – a four-ton spherical bomb. A low-flying Lancaster bomber had dropped it in the sea, but instead of bouncing along on the surface of the sea, it had shattered and sunk before their eyes.

  The bouncing bomb was Wallis's invention – an invention with which he hoped to destroy the Germans’ heavily-guarded power and water supply dams, vital to the Ruhr where most of Germany's heavy industry was concentrated. “An Engineer's Way to Win the War” was how he had described it.

  “I just don't understand it,” he said to mathematician Professor Taylor, as he recovered his thick, horn-rimmed spectacles from his pile of clothes and replaced them on his nose. “We gave the bomb the right amount of back spin. We dropped it from the right height, and at the right speed. And yet – crunch – it falls to pieces.”

  He shivered in the cold spring air, as he dried himself on the only thing available, a large pocket handkerchief. He was in no doubt as to the bleak future. The whole operation – crews, aircraft and bombs – had to be perfect by May 10, 1943, which was less than four weeks from now. Only then would the moon be full – and the enemy reservoirs.

  For three years he had campaigned for the recognition of his project, and now at last people had listened to him. He had blown-up scale models of dams and shown that his shockwave theory of destroying them held, but only so long as the bombs could be exploded in contact with the dam wall. He had developed small-scale bombs that would bounce over the defences, and cling to the dam wall as they sunk. Colossal sums of money were being invested in the operation now – not just the £400 his tiny model-dam experiments at the Road Research Laboratory had cost.

  Against military and civil-service opposition, Mr Churchill had intervened and ordered the establishment of a special Lancaster bomber squadron, and that unit, No. 617 Squadron, was even now training for the one task of destroying the five major Ruhr dams. Twenty-one Lancaster bombers had been taken off the production line at Avro's and drastically modified to carry the special spherical bomb that he, Wallis, had promised would do the trick.

  So now there was only one snag: the full-scale bomb was a failure. The first time they had dropped it, a monster steel cylinder padded out to the shape of a sphere with wooden packing, it had burst as soon as it struck the sea. That was no good at all.

  ON THE DAY AFTER their fruitless bathing party, Wallis and the other experts watched three more full-scale bombs dropped in the English Channel off Reculver by the same Lancaster. Two had been given a special varnish coating, and the third was finished in plain wood. On
the first run, the sphere stayed intact but sank immediately, without bouncing. The second bomb shattered into fragments, just like the one they had dropped some days before.

  Wallis groaned, and steeled himself for the failure of the third.

  As the Lancaster roared past this time, something unexpected happened. The bomb hit the sea, and the wooden casing completely disintegrated just as before. But the bare steel cylinder was left, still madly spinning, and this burst out of the tower of spray and hopped quite clearly several times across the sea, covering finally a distance of seven hundred yards.

  “The sphere broke up,” exclaimed Walls, speaking more to himself than to the others. “But the cylinder ran just as it should have done! It ran!”

  He gave orders for full-size bombs to be manufactured keeping the steel cylinder shape, but bare of any kind of wooden casing. Early on April 22, the Lancaster test-dropped one of them off the same deserted beach from a height of 185 feet. This test too was a failure, but Wallis was sure he knew a way of licking the problem. His staff saw him reach for his slide-rule and a pad of paper.

  Two days later, he met with Wing Commander Guy Gibson, 617 Squadron's commander, and put it to him.

  “I know this is asking an awful lot,” Wallis said hesitantly. “You must tell me at once if it can't be done. Can you bring your planes down to a level sixty feet, instead of 150, and make exactly 232 miles an hour, before you release your bomb?”

  Gibson swallowed hard. He thought, If 150 feet is low, then sixty feet is very low. At that height you've only got to hiccup to land in the drink.

  But he loyally replied, “We'll have a crack tonight.”

  When the morning chosen for the final crucial trials dawned, it was pouring with rain and there was a freezing wind. Wallis and the Air Ministry experts again crowded the foreshore at Reculver beach.

  Just sixty feet up, the black Lancaster bomber roared past them. As the bare steel cylinder dropped from its bomb bay, spinning backwards, and slowly fell towards the sea, Wallis silently prayed.

  It struck the sea with a crash – and emerged from the plume of spray making a gigantic bounce. The bomb bounced, bounced, and bounced again – each time striding hundreds of yards forward and throwing up huge spouts of water as though an invisible giant was stamping across the sea. Then it settled, and sank from sight.

  Wallis had done it!

  In his mind's eye, at the moment that his “bouncing bomb” disappeared from view, Barnes Wallis could see a huge masonry wall looming across the horizon, towering up out of the waves – a wall suddenly rent by blast and collapsing under the weight of millions of tons of water: the Möhne Dam.

  Then the others were crowding round him, clapping him on the back and congratulating him. Wallis allowed himself a cautious smile, as he returned to his car.

  ONE TRIAL ALONE was not enough, of course. Other tests followed, to get the speed of the aircraft and the amount of back spin imparted to the bomb just right.

  A means had to be found for aircraft to fly at precisely sixty feet over smooth water by night – an apparently suicidal task. Then someone remembered that a similar problem had been solved by an inventor in the First World War, who had proposed mounting two Aldis lamps, spotlights, underneath a plane at its nose and belly, angled so that their beams would only intersect at a certain height. In a surprisingly short space of time the actual apparatus was found gathering dust in a store at Farnborough, and the contraption was adapted for Guy Gibson's squadron.

  After testing this strange device over empty airfields, the crews went out over the Wash, getting down as low as they could, and soon they were hitting targets only six feet across with practice bombs, an accuracy almost unheard-of in those days.

  One day early in May, a Lancaster dropped the first special bomb to be fully charged with its explosive: a huge pillar of water shot up, towering hundreds of feet into the sky. Barnes Wallis's work on the weapon was complete; everything was now up to Gibson and his crews.

  A number of his men flew down to Kent to drop a dummy version of the bomb over the sea off Reculver. They had to get the feel of how their Lancasters would react, particularly to the gyroscopic forces unleashed by nine thousand pounds of revolving steel before the bomb was released. The vibration was intense.

  “You had to try and hold the plane steady,” said Shannon. “Our only target was a couple of posts on the beach.” The posts marked the separation of the towers on the Möhne dam. “We had to fly towards them … get down to the height and line up with them, with a handheld ‘V’ bombsight, which would determine the distance we were away, before we dropped the weapon. When released [it] behaved like a flat stone that skimmed across the water from your childhood” – like Ducks & Drakes, in fact, but deadlier.

  Seventy-two hours ahead of the operation the special weapons were delivered to No. 617 Squadron's crews. Until the modified Lancaster aircraft were actually flown in, the men had trained on the conventional Lancasters. The bomb itself looked to them like the heavy front roller of a steamroller. To rear-gunner Tony Burcher it looked more like a giant jam tin.

  *

  At three o'clock on the afternoon of Saturday May 15, 1943 Wallis climbed into a white Wellington aircraft with his Chief Test Pilot “Mutt” Summers and Major Kilner, Vickers’ managing director. There was a big Red Cross on the aircraft's sides – it was the only plane available.

  In brooding silence, the little party flew from Vickers’ aerodrome at Weybridge up to the operational bomber station at Scampton. Eighteen of No. 617 squadron's nineteen specially modified black Lancaster bombers were already waiting at their dispersal areas.

  Guy Gibson met Wallis as he climbed down the Wellington's ladder. “The AOC's just told me we're doing the job tomorrow night, if the weather holds,” he said.

  Wallis nodded absently, unable to believe that after three years of an increasingly frustrating battle against bureaucracy, the day had come when 133 hand-picked RAF officers and men were to stake their lives on the accuracy of his calculations. How could he express his feelings to these men? He was nearly sixty – they were almost without exception under twenty-three; young, carefree, and eager.

  Young though they were, their faces wore the battle-hardened expressions of veterans. All had completed two tours of bomber operations, so there were no greenhorns among them: all had been decorated, and all were experts in their deadly crafts. They were the elite.

  The weather forecast was favourable. There would be moonlight over the targets. “Security was very tight,” recalled one pilot. “No telephoning out, all mail was censored or held over.” For weeks Guy Gibson had threatened to broadcast over the station's Tannoy system any letter that contained any classified information. “There were some pretty juicy letters being written in those days to girl friends,” said the pilot. Gibson threatened to do the same with telephone messages – that he'd read the whole conversation out. One of the officers was dismissed for breaching security – he was found to have telephoned his girl friend on the day before the operation. Gibson could be both brutal and coldly efficient. He called a full parade, and dismissed the man in front of the squadron. Their mission was already dangerous enough. Secrecy was essential. Nothing else mattered.

  There would be nineteen crews, flying in three formations. Now for the first time they learned of their real targets for the raid, the dams. There was general relief that it was not the Nazi battleships. Several of these airmen had seen action against them as they escaped up the English Channel in February 1942: “I actually saw the Halifaxes bombing them,” said Tony Burcher, who was an air gunner in the elderly Hampden bombers at the time. “They had a umbrella of Messerschmitt 109’s over them and the Halifaxes were being chopped to pieces. I had never seen so much flak in all my life.” Nobody had relished the idea of going in to attack these battleships at a height of sixty feet. The Ruhr dams sounded quite harmless. Surely they would not be nearly so well defended?

  The wraps were taken off
contour scale models of the Möhne Dam, the Eder Dam, and the Sorpe Dam and the airmen were instructed to study them. Officers briefed them on the targets’ strategic significance and the enemy's night-fighter and flak defences along the flight routes.

  At six o'clock, Barnes Wallis faced the nineteen captains of aircraft for the first time: chalk in hand, standing on a platform in the almost empty Briefing Hall, the inventor repeated the now-familiar explanation of the crucial importance of the Ruhr Dams to Hitler's war industry. Then he gave them the scientific theory.

  “Your airspeed at the time of release must be 220 mph and your altitude exactly 60 feet. The distance at right angles over the water, back from the dam wall, is exactly 410 yards. The bomb will bounce three times, arrive at the dam, roll down the face of the dam to a depth of thirty feet and explode.”

  As he spoke, Wallis recalled how many times he had appealed for this attack before. What if there were some unconsidered factor even now, which would prove his theories wrong? The effect of gravity in such an enormous structure as the Möhne Dam, for example. It did not bear thinking of.

  Wallis finished his lecture. He slowly surveyed the curious faces through his spectacles, and said: “You see, you gentlemen are really carrying out the third of three great experiments: we have tried this out on model dams, and we have tried it out on a dam one-fifth the size of the Möhne. I can't guarantee that it will come off. But I hope it will… ”

  Heavy eight-wheeled trucks were rolling across the airfield as he left the Briefing Hall. Each was laden with the big cylindrical bombs, covered with tarpaulins, and each was still warm from the four tons of special high-explosive cast inside it at Woolwich Arsenal.

  In Guy Gibson's crowded office, the final plans were hatched. Code-words had to be arranged, last-minute alterations to bomber routes worked out. He and Wallis stayed there until after midnight. This time tomorrow Gibson would already be over the Möhne Dam, and Wallis would know whether his calculations had been correct.