Security had never been so tight before any other operation in Kit’s career. The public phones were cordoned off. The guards at the gates stopped anyone trying to leave. An unfortunate corporal who tried to slip under the perimeter fence — as almost all the erks did from time to time — found himself demoted to aircraftsman. Meanwhile, at a feverish pace, the bomb-bay doors, mid-upper turrets, forward turrets and guns, along with two guns from the rear turret, were removed from most of the squadron’s aircraft. On these modified aircraft, even the wireless operator’s station and all his equipment were stripped out to lighten the aircraft and make room for a monstrous bomb. At 26 feet long, it was almost twice the size of the Tallboy, weighed 22,000 lb and was known as the “Grand Slam” or Earthquake bomb. It was the latest invention of Barnes Wallis.
The first prototype had been used less than two weeks earlier against the Bielefeld viaduct, which collapsed under the impact. Its second outing had been against the Arbergen railway bridge, a few miles south of Bremen, only six days ago. Both operations had been carried out by 617 squadron, but on the first occasion with only one aircraft, and on the second two, modified to deliver Grand Slams. Now it was to be fourteen.
Moran was glad that Zebra was not among those subjected to these — to his mind — disfiguring modifications. Although Peal had performed well on the last four ops, including the daylight op to Bielefeld, Moran did not want to lose the back-up offered by Tibble. Nor did he like the look of the Lancasters carrying the Grand Slam. When laden and in flight, the fuselage sagged between wings that visibly curved upwards, and the slightest turbulence caused the wings to flex dangerously. It took every ounce of power from the four Merlins to drag the laden aircraft off the runway, and when the Grand Slam dropped, the aircraft sprang up 500 feet or more. Squadron Leader Jock Calder’s bomb aimer, who had dropped the very first of these bombs, said that after the release he’d been pressed to the floor of the Lancaster only to then be flung up again so hard that he was winded when he smacked down again. Meanwhile, Moran flying behind in Z-Zebra with a Tallboy, had been hit by the pressure wave following the detonation of the Grand Slam; Z-Zebra had been flung across the sky. Moran happily left the glory of delivering Grand Slams to others.
Although the briefing took place in broad daylight, the blackout blinds and curtains remained closed, and a tangible sense of nervousness agitated the briefers. This edginess spread rapidly to the assembled crews. Cigarettes glowed across the room and swirling smoke accumulated under the low ceiling long before they came to attention at the arrival of the senior officers.
The intelligence officer opened with: “Gentleman, at great risk to their own lives, a number of intelligence operatives have smuggled information out of Germany about a new kind of U-boat, designated Type XXI. These U-boats, being primarily battery driven, can operate for days underwater. They make less noise when underwater than conventional U-boats, rendering them almost undetectable to sonar. Furthermore, they have a submerged speed of 17 knots.” A ripple of astonishment swept the room. Many merchantmen couldn’t travel at that speed even on the surface. “They dive faster than conventional U-boats, recharge at periscope depth, and have no fewer than six forward torpedo tubes. They put to sea with a total of 23 torpedoes.”
There was an uneasy stirring among the aircrews.
“Needless to say, U-boats of this type would wreak havoc with our merchantmen and with the sea lines of communication to our ground forces on the Continent. It would be too much to say that they can save Germany from defeat, but if they are deployed in the numbers planned, they could prolong the war by months — not to mention send hundreds of Allied ships with their cargoes and crews to the bottom.”
We get the drift, Moran thought to himself, lighting another cigarette. Get to the point.
“Tens of thousands of slave-labourers, working under appalling conditions, have built a factory capable of mass-producing these Type XXI U-boats. It is 90% complete and the machinery installed. Our intelligence suggests that within a week it will begin production and start turning out three of these superior U-boats every week.” He paused again and looked toward the Station Commander.
The latter stepped onto the stage and announced: “Gentlemen, His Majesty’s government expects you to ensure that does not happen.”
Moran raised his eyebrows and glanced over at Squadron Leader Martin, who was sitting beside him. They exchanged a look of mild irritation.
The Group Captain gestured for the curtains covering the target map to be opened. On the revealed map, a line of yarn led to a suburb of Bremen on the Weser River, and the whole room groaned. Bremen possessed some of the heaviest flak and best fighter protection in Germany. Tapping with his pointer, the Station Commander continued. “Here you see the large concentration camp housing the slave labourers. Here you see the flak fortresses.” His pointer tapped on the map at least a half-dozen times. “What you can’t see is that the factory,” as he spoke, he traced the outline of a large rectangular area with the tip of his pointer, “is protected by a concrete ceiling 14-feet thick at the western end and 23-feet thick at the eastern end.”
The crews shook their heads and the cigarette smoke fogged the air more and more.
“You’ll be going in at 18,000 feet, which will allow the Grand Slams to reach supersonic speed. This should enable the bombs to pierce the concrete and explode inside this massive structure, where the machinery for producing the submarines has already been installed. The fuses will be set to detonate with a ten-minute delay. When the bombs go off, the factory’s protection will be transformed into the cause of its destruction. The massive walls will contain the blast and wreak more destruction than if the building were blown open. This means, of course, that you may not see much damage, certainly not from 18,000 feet. However, we have operatives among the workforce and the local community who will report back on the effect of our assault.
“Meanwhile, those of you carrying Tallboys are to concentrate on the surrounding structures that house the guards, the staff, and the railway sidings used for the delivery of raw materials, component parts, and so on.” The Station Commander tapped targets with his pointer as he identified them.
“What about the slave labourers? Will they be inside at the time of our strike?” The question popped out, and only after he’d voiced it did Moran wonder if he’d spoken out-of-turn.
The Station Commander looked annoyed, but Fauquier stood and turned to face him. “The Nazis have slaves working around the clock to get this finished, Moran. There is no time when it is not full of labourers. This is one op, I’m afraid, when we cannot take any measures to minimise the civilian casualties. We must press ahead.”
Moran nodded. His question, however, had loosened tongues.
“Will we have an escort?”
“You will. One squadron of USAAF Mustangs and one of our own Spitfire squadrons.”
“How many German fighter squadrons are stationed in the area.”
“Will there be a diversionary attack?”
“Yes, ninety-five Lancasters from 5 Group Squadrons will carry out a simultaneous raid on a nearby oil storage depot.” Fauquier paused. “Any other questions?”
There were none, and the briefing continued with the details of fuel loads, routes, marking and timing.
Click Follow to receive emails when this author adds content on Bublish