The Dam Busters

^{CHAPTER XIII} THE MOSQUITO PLAN

COCHRANE was not yet convinced that low level marking was practicable, but he told Cheshire he would lay on more lightly defended targets so the experiment could go on. He wanted the system perfected by the time Wallis’s “tallboy” was ready; the first one was nearly ready for testing, and after that they would be some time building up stocks. Meantime the squadron needed some re-forming. With Martin and Suggitt gone there were no flight commanders.

It was Cochrane’s idea to split 617 into three flights for easier organisation and training; a happy idea, because it gave Cheshire a chance to promote Shannon, McCarthy and Munro, now the only three of the original squadron left, and all battle-tested, reliable and ideal in temperament and training for 617’s unique role.

The squadron had several new pilots now, including another American, Nicky Knilans, a droll youngster from Madison, Wisconsin, with precisely the quality of nervelessness that Cheshire wanted in 617. He had joined the Canadian Air Force before America came into the war and had just recently been transferred. Now a “lootenant” in the U.S. Air Force, he wanted to stay and finish his tour in the R.A.F.

In the next few weeks 617 was busy training new crews and settling down with the new flight commanders. Cheshire and “Talking Bomb” kept flying around at 5,000 feet trying medium-level marking, but could find no way of lining-up an indistinct target. Cochrane told them to keep trying.

The first couple of prototype “tallboys” were finished, and at Ashley Walk range, in the New Forest, the complicated process of testing them started. They were sinister objects, 21 feet long, shining blue-black steel, slim and perfectly streamlined, weighing 12,030 Ib. A Lancaster dropped one on test from 20,000 feet, and it sliced through the air like a bullet till it was falling faster than a bomb had ever fallen before. Long before it hit it passed the speed of sound, and as the compressed waves of the sonic barrier piled up round it the bomb vibrated in flight so that it almost toppled and was deflected slightly from its even course, just enough to interfere with the fanatical accuracy that Wallis wanted.

He overcame it with a brilliant idea, offsetting the tail fins so that, as the next bomb dropped and gathered speed, the offset fins began to revolve it. Faster and faster it whirled till by the time it reached the speed of sound it was spinning like a high-speed top, and the gyroscopic action held it perfectly steady as it plunged through the sonic barrier.

At Ashley Walk they dropped one with dummy filling from 20,000 feet and it sank 90 feet into the earth, almost enough for the maximum camouflet that Wallis had planned from 40,000 feet, and certainly enough to make a respectable earthquake.

Came the day of dropping the first “live” one, and they buried a movie camera in the earth to film it. There was some discussion as to where the camera should go, and perhaps it was logical (if a little cynical) that they decided to bury it right in the centre of the white circle that was the target, on the assumption that it was the safest spot.

The result was a lesson for anyone who doubted Wallis’s genius. Peering over the edge of the sandbagged dug-out half a mile away, they saw the slim shape streak down and hit the centre of the target, right on the camera! The dug-out trembled, and where the camera had been was a smoking, stinking; crater eighty feet deep and a hundred feet across.

Cochrane called Cheshire to Group H.Q. and told him the earthquake bomb had passed its tests with honours and they were now building up stocks for “a big operation” in the spring and summer.

Cheshire had been pondering some new marking ideas. It seemed to him that Lancasters were too big and clumsy for marking; too big a target for the flak and too clumsy for manoeuvring low over rough ground on pin-point targets. He went to Cochrane and suggested that he try marking in a Mosquito, and Cochrane liked the idea. The twin-engined Mosquito was much faster as well as smaller and “nippier”. Provided Mosquitoes could be used, Cochrane for the first time began to feel more comfortable about the idea of sending crews out to mark at low level.

A new idea was already growing in Cochrane’s mind: to have 617 mark for the whole of his Group, about twelve squadrons, instead of the Pathfinders. He had already sounded out Harris on his new idea and Harris had reacted favourably. Cochrane reasoned that if they could show that low marking in Mosquitoes was reasonably safe, Harris would probably give 5 Group its chance. He said to Cheshire:

“Well, I’ll see if I can get you a couple of Mosquitoes, and then I’d like you to try them first on easy targets. If it seems all right, you could have a go at a tough one.”

It was not easy for Cochrane to get hold of Mosquitoes for 617. They were in short supply and great demand. While he was working on this, 617 visited the explosives factory at Bergerac, on the banks of the Dordogne.

For once, in the light of flares, Cheshire’s bomb aimer, Astbury, got a good sight at 5,000 feet and put his markers on the factory. Munro did the same. Shannon and McCarthy branded the explosives dump near-by, and Bunny Clayton put a 12,000-pounder in the middle of the dump. For fifteen seconds it looked as though the sun was coming up underneath; five minutes later the factory as well as the dump was a sea of flame. No bomb fell outside the works.

A pleased Cochrane rang Cheshire next day. “Pack your over-night bag,” he said. “You’re coming down with me to see Air Chief Marshal Harris about a couple of Mosquitoes.”

That night they dined with Harris in his house near High Wycombe. Over the port Harris suddenly said, “Cheshire, what makes you think you can mark from nought feet in a Mosquito and get away with it?”

“There’s no question that we can mark accurately, sir. The only thing is having a reasonable chance in the face of heavy opposition. Air Vice-Marshal Cochrane thinks a Lancaster is too big and slow. Against heavy opposition I’m inclined to think now he is right, but I believe he agrees with me that the chances in a Mosquito are good. I believe in a Mosquito we can have a go at any target under the sun and mark with under twenty yards accuracy.”

“I’ve always wanted to bomb Munich properly, and I’ve never succeeded,” Harris said. “It’s got four hundred guns. D’you think you could mark that on the deck and get away with it?”

“Yes, sir. I do.”

Cochrane cut in, saying that they should practise first with the Mosquito on less lethal targets so they would know precisely what was possible.

“All right,” Harris said, “I’ll see if I can get you two Mosquitoes… just on loan for a month. If by that time you can mark Munich accurately for me, you can keep them.”

Just behind Calais the Germans had started work again on the bornb-proof rocket and long-range gun bases. Thousands of slaves were crawling over the massive blockhouses and it was obvious that the secret-weapon project was nearing completion again. Whitehall knew now that the weapon was to fall on London and the invasion ports, but kept it very secret. If the secret weapons started up before the invasion and the R.A.F. could not destroy the blockhouses, London would be destroyed and it was likely that the invasion would also be wrecked..

Churchill was insisting on twice-daily Intelligence reports. Some reports put the weight of the secret-weapon warhead as high as 10 tons of explosive and suggested they might fall at a rate of thousands a week. Churchill ordered the preparation of plans for the evacuation of London and told Sir Arthur Harris that the blockhouses were to be destroyed without fail before they were ready for action.

Wallis’s “tallboy” was the only weapon Harris knew of that might smash them, but the “tallboys” would not be ready for some time. They would have to be dropped from at least 18,000 feet to get enough speed for penetration, and only one squadron could drop them accurately enough. But the sites would be so well camouflaged in the bomb-pocked earth that a bomb aimer would have trouble getting them in his bomb sight from 18,000 feet even by day. Though the sites were fairly plastered with flak they would have to be marked clearly and with unprecedented accuracy because there would be no “tallboys “to waste. It was a pretty problem, and Harris called the Pathfinder chief, Bennett, and Cochrane and Cheshire to a conference at his headquarters.

Bennett said frankly that the Pathfinders were not equipped to mark with such accuracy, and Cochrane suggested that 617 might be able to do the marking as well as the bombing.

Cheshire said: “I doubt if it could be marked accurately at medium level. You’d have to run-up straight and level, and at that height the searchlights would blind you so you couldn’t see the target, and the flak would pretty surely get you anyway. I should think, sir, we could mark it at very low level in a diving attack.”

Cochrane said warningly, “Not in a Lancaster.”

“No, sir. In a Mosquito, as we discussed before. She’s so fast we could be in and out before the defences could nail us.”

A day later Cochrane phoned Cheshire: “I’ve got two Mosquitoes for you. They’re over at Colby Grange. Go and learn to fly them and be quick about it. Let me know as soon as you’re ready to use them.”

Cheshire was delighted with the Mosquitoes, and within two days felt at home in them. The only possible fault he could find was that, carrying a load of heavy markers, their range might be a little short for some of the more distant targets. Munich, for instance, would be barely within range, so he asked Group to get him some long-range drop tanks as soon as possible.

Signs of the squadron’s growing prestige were not lacking. March brought them nine more decorations; popular ones. Among them were a Bar for Martin’s D.S.O., a second Bar for Cheshire’s D.S.O., a Bar for Whittaker’s D.F.C., and the D.F.C. to add to Foxlee’s D.F.M.

Cheshire flew down to Weybridge to see Wallis about tactics for dropping the “tallboys”.

“I haven’t really designed this thing for concrete,” Wallis said, “so I think, my dear boy, it might not be a good thing to drop them right on the roofs of those wretched concrete affairs; they might bounce out again like corks. However, you needn’t worry; just drop them down at the side in the earth and they’ll bore down and blow them up from underneath.” He stuck pins in a diagram to show the vulnerable points and added disapprovingly, “The Germans are very silly not to put twenty feet of concrete under these things, not on top.”

Cheshire suggested as tactfully as he could that, though he had enormous faith in his squadron, it was one thing to stick pins in a diagram and another to drop a bomb in that spot from 20,000 feet.

“Oh well,” Wallis said huffily, “if I’d known you propose to scatter the bombs around the countryside like grass seed I’d never have bothered to design them.”