By the middle of 1942, Great Britain and the British Empire (now called Commonwealth) countries had been at war with Nazi Germany for three long years. It was not until the Japanese attacked Pearl Harbor that the Americans realised they could no longer be isolationists and they had to join the struggle against fascism.
The war was being fought on land, mostly in North Africa; at sea, mostly in the Atlantic and in the air. The Battle of Britain had been fought and won, the Germans continued to bomb British towns but the Royal Air Force was increasingly penetrating German airspace to bomb strategic targets in the German industrial heartland.
Barnes Wallis was more of an engineer than a scientist and had developed a good reputation. His biggest success up to that point was the design of a twin-engine bomber, the Vickers Wellington. The design of the structural framework made it extremely strong and it was able to withstand and still fly with heavy battle damage.
He came up with the idea of depriving the German steel industry with the water essential in steel making. He realised that blowing up the dams holding billions of tons of water in the vast reservoirs would do the trick. But there were no bombs large enough or, for that matter, any aircraft that could carry such bombs – even on the drawing boards.
He then thought that as a child he had, like other young boys, skimmed pebbles across a river and a lake. After a time he had became skilled enough to get the pebbles to bounce several times before sinking into the water. He reasoned that if a bomb was dropped from a very low height and that it was spinning when it hit the water then it too might bounce. What he was looking for was to get a bomb to come to the end of its bouncing against the walls of the huge dams. If it were still spinning it could crab down to the base of the structure. When it exploded, the surrounding water would create an earthquake effect. Bang and away goes the dam.
All very well in thinking but a devil’s problem to get it to work. His reputation went before him and after months of meetings he was given approval to try out his idea using a Wellington bomber. On most drops, the bomb casing broke up and the bomb was dead in the water. Eventually he was successful and, again because of his reputation, Air Marshall ‘Bomber’ Harris approved the formation of a new specialist squadron for the attempt.
A wing commander (equivalent to a Lt. Colonel) was chosen to set up the squadron. Although only 24, Wing Commander Guy Gibson had completed 173 missions into Germany. He was a tough cookie but a good leader. He selected the pick of bomber command and known low-level flying enthusiasts and had them sent to RAF Scampton. As they were training at low-level flying, they were not doing any conventional raids. Others were asking why this was so. The pilots on the new squadron were all resplendent with medals so tongues started to wag and Gibson had to be tough on security.
Britain had an enormous pool of men, and women for that matter, willing to leave their sheep farms in Australia or New Zealand, their families in South Africa and Canada to come to the Mother Country to fight the Nazi fascists. A very high proportion of those who would make up 617 Squadron were from these colonial countries. Before the United States joined the war, one American Coney Island beach guard broke the US laws and went north into Canada and joined the Royal Canadian Air Force. After training he was transferred to Bomber Command in Britain.
None of those who joined 617 Squadron were told what the target was to be. They trained at night flying, at extremely low level, over lakes and reservoirs so naturally but mistakenly thought the target was to be the German battleship Tirpitz, skulking in the Norwegian fiords.
When we think of low flying that is no exaggeration. One hundred and fifty feet maximum height in a Lancaster bomber with no hydraulic assistance on the controls was no mean feat. The bomber had a wing span of over 100 feet, larger than a Boeing 737, so twisting and banking to make approaches on to targets called for cool nerves.
They knew they were dead men anyway. The crews had to complete 30 missions before they were given any respite. With an average loss rate of over five per cent only the lucky ones completed their tour before being shot down by German night fighters or anti-aircraft guns; either killed outright or taken prisoner. The aircrew had to face action day after day with only their conscience to guide them.
But then in parallel with the training was the construction of the first bombs. A new design of bomb weighing 4 tons (over 8,000 pounds) that had to be spun whilst suspended underneath the aircraft was a tall order. The first actual drops ended up with the bomb’s casing breaking up on impact with the water. It had been determined that the drop had to be from 150 feet, 1,200 feet from the dam and at a speed of 220 miles per hour. The question was – if the bomb was dropped from just 60 feet would it work without breaking up? Gibson told Barnes Wallis they could fly to those limits – with luck. They installed two Aldis signalling lamps underneath the aircraft, one facing to the rear and the other forward. At 60 feet the two beams coincided and they were spot on height. They found getting the range exactly right was a nightmare until they used an old wooden coat hanger with a couple of nails. When the nails lined up with the towers on the dams they were at the right spot to press the button and yell, ‘Bomb away’! The next trials over the sea on the Kent coast worked. But could they do this over Germany with defensive guns firing at them?
The beginning of the end of the preparation
The time to train had now come to an end and the time to put everything into action dawned. Gibson with his two flight commanders determined the three groups of aircraft and which was to attack which dam. The first dam was the Moehne, the second was the Eder and the third the Sorpe. If the attackers could destroy one dam it would justify all of the effort that had been expended. If they could get two, it was a bonus.
The day was taken up by preparing the aircraft with flight tests to ensure all systems on each aircraft were perfect. The armourers loaded all guns and the special four ton bomb on to each aircraft. Due to the size of the bomb and the weird mechanism to make it spin whilst still attached to the aircraft at 500 revolutions a minute, it could not be fully located in the bomb bay. It hung down quite a lot, making the aircraft look very ungainly. (All pilots know that if an aircraft looks good it will fly well – if it looks ugly you have problems).
The crews were called for briefing at mid-afternoon and they knew it was not another training day. The array of senior men present told them that. Gibson started it off and introduced Barnes Wallis, who explained why they had to drop the bomb so low and at a specific speed. He explained that the bomb would bounce up to six times, skipping over the defensive torpedo nets the Germans had erected. He said that several bombs might be needed to collapse the huge dams but he was confident they would be successful.
Gibson and his flight commanders had divided the 19 aircraft into three waves. There was flexibility set in the plan such that if they were successful in breaching a dam with the first aircraft those that still had a bomb available could divert to secondary targets. On the other hand if they had lost aircraft the reserves could be brought into play.
Tactical matters then took quite a time with routes given to avoid concentrations of anti-aircraft guns and night fighter airfields. This is where the collective experience of the pilots came in as they were able to highlight places where there
were many anti-aircraft guns where they had almost come to grief in previous operations. It was reiterated that they should cross the North Sea and into Holland at 100 feet to avoid being spotted by German radar.
Flight to the target dams
At 9pm, with double saving daylight saving time, it was still light as the first wave started engines and checked all systems on the aircraft. At 9:30 pm the pilots opened the throttles and in a few moments they were airborne heading for the English coast, so familiar to them all. Each man must have wondered if he would see it again on a return journey.
The flight across the North Sea was intended to be so low that they would be undetected by the German radar defences who would alert the vast number, over 10,000, German anti-aircraft guns. In fact, Rice’s aircraft was so low it touched the sea. Sea water poured into the Lancaster’s bomb bay, the bomb having been ripped out. Rice managed to save the situation and returned sadly back to base. One down already and they hadn’t reached the enemy coast yet.
Munro was hit by a large shell that destroyed the intercom system. It sounds a simple matter but the bomb aimer had to be able to speak to the pilot to give directions on the final run to the dam. Munro had no choice but to return to base. The whole crew were bitterly disappointed.
Byers was hit by anti-aircraft guns over Texel and exploded. The same fate was experienced by Astell’s when his aircraft hit power lines and exploded. The remaining aircraft in the first wave arrived in the Moehne area and circled to determine the best approach. They also had the opportunity to see the anti-aircraft defences.
First wave attack on the Moehne
Gibson, as leader, made the first attempt but decided to go around again to get his height and speed correct before releasing his bomb. When he was satisfied his bomb aimer released the monstrous bomb. Gibson was disappointed that his bomb exploded on target but failed to breach the dam. Hopgood was next but was hit by cannon fire from the towers on the dam. His bomb went over the dam and hit a power station on the far side that was obliterated. His aircraft ploughs din the woods and also exploded.
Aircraft captained by Martin and Young also had unsuccessful attacks, their bombs were on target but the massive dams refused to collapse. Maltby’s bomb finally did the trick and the dam was breached.
Gibson said afterwards, “A tremendous sight, a sight probably no man will ever see again.” As a tidal wave from the released waters was unleashed Gibson sent the coded signal back to base with the message that they had succeeded.
The attack on the Eder dam
Gibson led the remaining aircraft still with bombs to the Eder dam. The approach to this dam was much more difficult because of the surrounding hills. Shannon aborted his attack several times before releasing his bomb. Maudsley misjudged his height and his aircraft was lost when the bomb exploded on the dam parapet, directly beneath his aircraft. Knight, with the last available bomb, successfully made the breach that was to add to the flood devastation in the Ruhr. Having completed their mission the surviving aircraft set course for home, a long flight away and night fighters and anti-aircraft to avoid. Young’s aircraft was hit by ground fire and was lost over enemy territory.
Now for the third target, the Sorpe dam
It was known that this would be a difficult dam to breach, even though it was huge it was constructed of earth rather that masonry.
The second wave aircraft were in trouble from the start. Munro had been hit and with Rice managed to return to Scampton. Byers was shot down and Barlow was another that hit high tension power lines. The fifth, captained by American, but in the Royal Canadian Air Force, McCarthy damaged the target but to his chagrin did not breach it. The third wave lost two more aircraft, Ottley’s and Burpee’s and although they dropped their bombs did not destroy it.
Of the 19 aircraft that set out that night, 11 returned. Eight were lost, a total of 56 very brave men killed. Eight out of 19 is a high percentage. Nevertheless, Bomber command chiefs were elated. Not only was it a good strike against Germany’s electricity and steel industries, but also a good propaganda story to counter the high losses experienced night after night.
Gibson was awarded the Victoria Cross, the highest award given by the British for bravery. Sadly, he was lost, like most of the survivors, in the two years of bombing that followed.
For the rest of the war, 617 Squadron was kept in action for especially difficult and often precision targets. Barnes Wallis was finally allowed to design 6 ton, Tallboy, and then 10 ton, Grand Slam, bombs for use by 617’s Lancasters at extremely high levels against specialist targets that required penetration of enormously thick (40 feet) concrete bunkers.
A personal note
One of the pilots, Mac Brown, had won a bet in the mess at an airfield in the West Country when he said he could fly his aircraft into a gorge under the Clifton bridge. But his aircraft number was spotted by a policeman and he was in trouble. He managed to get away with an admonishment. A week later he was told to go to Scampton and when there in a small office he was interviewed by Gibson. “I see you like breaking the rules on low flying,” said Gibson. “Surely that is over and done with, Sir. They have chewed my rear end off for that all ready.”
“If you are comfortable with low-flying, Brown, get your kit into the mess, you are joining my new squadron.”
Mac survived the raid and many others in the next two years although he was wounded in the leg. I became friends with him much later on. His party trick for Cub Scouts was to show the eight year olds how they could hold up their long woollen socks with drawing pins. The Scouts all neglected to volunteer to follow his example. Mac didn’t tell them the nerves in his leg had been cut by shrapnel in 1945 and he couldn’t feel the pins.
Graham Walker has always been interested in military history but it is pointed out that any thoughts and expressions are personal and not that of the association.