At 7.18 a.m. on 23 March 1918, an explosive shell landed on the Quai de la Seine area of Paris. France was of course four years into the bloodiest war in history so the presence of shelling shouldn’t have been a great surprise – except, the front line was over 96 km (60 miles) away at the time. At first, Parisians looked to the sky thinking they had been bombed by a German Zeppelin – but that was not the case.
The shell that fell on Paris hadn’t come from a Zeppelin, but rather a new piece of German artillery sat 120 km (75 miles) away from Paris in the small town of Crepy. Twenty-one further shells landed on the French capital that day, usually in 15-minute intervals, a process that continued sporadically for the next 5 months. The goliath that was hurling these shells, came to be known as the Paris Gun – or as the Germans called it Wilhelmgeschütze – William’s Gun, after the Kaiser.
This is a piece of weaponry that is still very mysterious. We believe that 7 or 8 barrels were adapted to be used as a Paris Gun, but it seems that only one was ever used at any single time. At the end of the war, these simply vanished and apart from some grainy black and white photos, it was as if these colossal guns had never existed.
The Paris Gun
The gun that the Germans had built was staggering in many ways, yet exceedingly poor in others. It was a piece of artillery of truly monstrous proportions, weighing 256 tons and measuring a massive 34 metres (111ft) in length. Nothing like it had ever been created and it immediately became the largest gun in history – a title it held for another 23 years until the Nazi introduced the dramatically large Schwerer Gustav – which we have already covered here on Megaprojects, so if you’re having a big gun day, maybe that should be your next stop.
Anyway, back to the Paris Gun. It initially started pumping out 211mm (8.3 inches) shells, but it was later rebored to accommodate the larger 238mm (9.3 inches) shells – I’ll explain why a little later in the video. The gun was raised to an elevation of 55 degrees after which it let roar, firing a shell an extraordinary 40 km (25 miles) up into the air – which at the time was the highest a man-made object had ever travelled – before coming on the unsuspecting Parisians digging into their pain au chocolates and coffees – well that was the plan at least.
The downside of this freakish cannon, for the Germans at least, was its poor accuracy and relatively small amount of explosive in the shells, but it nonetheless struck plenty of fear into Parisians who no doubt still felt a world away from the carnage of the front lines.
The first cannons appeared in China sometime in the 12th or 13th Centuries and while their calibre and destructive power improved dramatically over the coming centuries, their range never really got above a few kilometres.
But then as World War I got underway, the Germans wheeled out Big Bertha, a 420mm (16.4 inc) Type M mortar capable of smashing targets 9.3km (5.7 miles) away. Nothing like this had ever been seen and it set off a mad scramble to emulate it.
The company behind Big Bertha was Krupp of Essen – widely regarded as the preeminent gun manufacturers at the time. As the Germans began rolling back French forces in the early stages of the war, their commanders envisioned soon making it to the English Channel, where they hoped they could use the next generation of guns rolling out of Krupp’s factory to begin hitting the English port town of Dover directly from France.
Things didn’t quite work out like that and the advance stalled in the Somme region where hellish fighting would go on for the next 4 years – but Krupp had done their part. Testing had already got underway on a 350mm (13.7 inches) gun capable of reaching 49km (30 miles) – easily enough to clear the English channel.
But instead of using them against England, these guns saw real combat testing against the English and the French near Verdun and Nancy. It was here that a strange quirk revealed itself. Geometry had long suggested that the optimal angle for a gun to be fired was 45 degrees, but as those taking note saw, these guns were working even better at 55 degrees. They soon determined that because the earth’s atmosphere is thinner the higher you go, long-range shells were travelling further because of the thinner air. So, even though it didn’t seem at all logical to fire the guns further up into the sky, it, in fact, meant you could hit targets further away. This was a lesson that was soon put to great use in the development of the Paris Gun.
Krupp’s technical manager Dr Fritz Rausenberger proposed an ultra-long-range 100 km (62 miles) gun to the German High Command sometime in 1915, which was immediately accepted as long as it could be delivered in just 14 months. Rosenberger’s sights initially settled on a series of 350 mm (13.7 inches) naval guns, initially allocated for a battlecruiser which had since been scrapped.
His idea was to insert a 21 metres (68ft) long 210mm (8.2 inches) calibre rifled liner while modifying the chamber to accommodate 280mm (11 inches) cartridges. His calculations determined that the gun would need to have a muzzle velocity of 1500m/s (4,921 feet per second) to reach 100 km (62 miles). Things seemed to be progressing smoothly until the German High Command announced the gun would need an extra 20 km (12.4 miles) in range because there was to be a planned withdrawal. Rausenberger crunched the numbers and found that by increasing the muzzle velocity to 1610m/s (5,282 feet per second), the gun would be able to reach 120 km (74 miles).
That’s all well and good, but how do you simply increase muzzle velocity? By making the gun longer of course. They found that to achieve the desired speed, the gun needed to have an in-bore shot travel length of at least 24 metres (78 ft), but unfortunately, Krupp’s boring machines only went up to 18 metres (59 ft). The problem was solved by simply bolting on an additional smoothbore tube, which came in three sizes depending on the range needed; 3 metres (9.8 ft), 6 metres (19.6 ft) and 12 metres (39.3 ft).
The last major hurdle the team faced was barrel droop – which is exactly what it sounds like. Long-range guns at the time often suffered from a slight droop in their barrels because of the massive weight. Normally this wasn’t a huge issue, but with the Paris Gun’s size, the droop was as much as 9cm (3.5 inches) at the muzzle, enough to horribly skew a shot. The solution was again fairly simple. The gun came with a suspension-bridge-like truss with screw-jacks which straightened out the barrel and allowed it to retain its form.
I mentioned earlier in the video, one of the saving graces for the Parisians who would be on the receiving end of the Paris Gun, was it’s relatively small amount of explosive. The shell itself fired from the gun weighed 106 kg (234 lb), but came with only 7 kg (15 lb) of TNT – only around 6% of the shells total weight. Whatsmore, the shell casing needed to be much stronger than traditional projectiles to withstand the enormous pressure from the gun.
This meant that the damage caused by these shells was small, in comparison to the size of the shells at least. A crater left in Tuileries Garden in Paris was recorded as being 3 to 3.7 metres (10 to 12 ft ) across and 1.2 m (4 ft) deep. Now, that’s not tiny by any means but is significantly smaller than the 9.1 metres (30 ft) wide and 9.1 m (30 ft) deep crater left by the Schwerer Gustav in World War II. The strong shell casing also meant that it would normally break apart in large sections rather than tiny fragments like other shells – which again was good news for those on the receiving end.
The real oddity regarding the ammunition used for the Paris Gun came because of barrel wear. These kinds of guns – in their unmodified state – could hope to fire around 800 rounds before accuracy was compromised. The Paris Gun, on the other hand, could handle only 60 to 70 rounds before the barrel needed to be bored out again.
And it gets even more complex. Each time the gun was fired the barrel would extend by roughly 7 centimetres (2.7 inches), which then required an additional 10 kg (22lbs) of propellant, but also the force and speed in which it fired meant that the barrel was ever so slightly bored out further with each additional shot. Remember how I said earlier that the calibre changed, well this was why. The Paris Gun essentially caused itself so much damage that it had to be rebored to continuing operating.
The Germans used shells that steadily increased in size to accommodate the changes within the gun. These shells were carefully numbered then fired in order, and I can tell you that whoever was in charge of that had one of the most important jobs. A shell that was too small would have little chance of firing straight, while one that was too big would lodge within the barrel causing the whole thing to explode – as I said, an important job.
This was not a gun that you could just wheel out whenever you wished, their mountings needed to be carefully prepared to house this outrageously large gun and required a purpose-built circular turntable set in a concrete emplacement.
While details are a little unclear on this point, it’s believed that the Germans built a series of these emplacements along the front lines, but only one was ever captured. American troops moving through Bruyères-sur-Fère, near Château-Thierry northeast of Paris, came across an abandoned Paris Gun mounting near the end of the war, but unfortunately, that’s as close as allied forces ever came to the giant gun.
As I mentioned earlier, the Paris Gun was essentially a naval gun, so it came with its own group of 80 Imperial Navy sailors who manned it. When it was first set up it was surrounded by several traditional pieces of artillery that were designed to provide a ‘sound screen’ which would cover the deep boom coming from the Paris Gun, a move designed to hide its presence from English and French spotters. It was first positioned in a forest area near Crepy to the north-east of Paris and let fly for the first time early in the morning on 23rd March 1918, landing in Paris around 3 minutes, with a further 21 coming that day.
By the end of the day, military authorities were fairly sure that the explosions were coming from shells fired by artillery and not from bombs dropped from the sky as had first been thought. Their focus instead turned to the possibility that they were coming from German agents located within France – the idea that a shell could travel from the front lines must have sounded preposterous at first.
Within a matter of days, reconnaissance aircrafts had spotted three large scale gun emplacements. The closest was targeted by a French 340mm (13.3 inches) rail gun, while aircrafts attacked the other two – but the shells kept coming.
Roughly 360 rounds were fired in the direction of Paris over 5 months. 250 people died as a result, with 91 of those came in a single event when on 29th March 1918, a shell hit the roof of the St-Gervais-et-St-Protais Church, collapsing the entire structure upon the Sunday service in progress at the time. There were three notable pauses in the shelling, which on reflection were probably when the gun was taken back to Germany to be rebored, these were between the 25th – 29th March, 7th-11th April and 21th – 24th April. French authorities also noticed an increase in the diameter of the shells which seems to support this theory.
In August 1918, with the war looking increasingly bleak for the beleaguered Germans, the Paris Gun was withdrawn and returned to Germany. A little over three months later the Great War came to a close. A conflict that had decimated northwest France and Belgium, causing an estimated 20 million deaths along the way.
But the French didn’t forget the Paris Gun and part of the Versaille Agreement stipulated that Germany would hand over one of these mighty guns to their Gaelic neighbours – which of course never happened. And that was the last we ever heard of the Paris Gun.
A Psychological Gun
Dr Fritz Rausenberger knew full well that the Paris Gun was nowhere near accurate enough to hit designated targets. Instead, it was a weapon that carried a psychological impact that far outweighed its physical impact.
The Germans hoped that by shelling Paris they might be able to break the will of the French, which might, in turn, lead to a vital break in the lines. It never happened. While the Paris Gun caused much Parisian consternation, it did little to dent morale. For that reason, it’s difficult to look at the gun as much more than a glorious tour de force of a weapon that looked better than it actually was. A mighty, thunderous cannon that certainly paved the way for big guns in the future, but was itself a complicated pain in the arse to use.