How Tanks Shattered the Hindenburg Line

0:00You're listening to a podcast right now, driving, working out, walking the dog. If you're in a podcast, chances are you have something to say too. With RSS.com, starting your own podcast is free and easy. Upload an episode and we distribute it to Apple Podcasts, Spotify, Amazon Music and more. Track your listeners, see where they're from, and start earning from ads just like this. If you've been thinking about starting a podcast, this is your sign. Or your new podcast for free today at RSS.com. Welcome to The Deep Dive. Today we are exploring a moment, while really a specific battle that completely rewrote the rulebook of modern warfare. Yeah, we're heading back to the Western Front, specifically we're looking at the Battle of Kimbray in late 1917. Right. And you know, when you think of World War I, the images that usually come to mind for most people are these static, muddy trenches. Terrible attrition. Exactly. Terrible attrition, years of deadlock where the front lines just, they barely moved in itch. Right.

1:00But this operation we're diving into today, it shatters that entire perception. We are basically looking at a masterclass in rapid innovation, the birth of combined arms and really how an influx of new technology forces militaries to adapt at just breakneck speed or, frankly, face annihilation. It's a massive shift. And to set the scene for any, if you imagine the tactical map shifting to the area around Kimbray, France, the geography and the pre-existing defenses there are central to literally everything that happens next. Because Kimbray wasn't just a random town, right? No, not at all. In late 1917, it was a crucial railway and supply hub. It supported the Seeksreed Stelling, which is what the British referred to as the Hindenburg Line. Right, the Hindenburg Line, which was famous for being virtually impenetrable. Exactly. Because this particular sector of the front had been relatively quiet for a long time, the German military had the luxury of time and resources. So they built an incredibly formidable defense in-depth. We're talking multiple trench systems.

2:02Multiple systems, concrete pillboxes and these massive belts of barbed wire that work get this up to 50 yards deep in places. 50 yards of just solid barbed wire, which really sets the stage for the massive contrast we are going to explore today because you have these supposedly impregnable static defenses suddenly facing down experimental mechanical beasts. Thanks. Right, thanks. And you have church bells ringing in premature celebration back in London, followed a few days later by the terrifying debut of an entirely new kind of infantry assault that just completely paralyzed the defenders. But a rollercoaster of an operation. Okay, let's unpack this. Because the battle plan didn't just come from some single top-down directive from a general in a chateau, it was emerging of two very radical, very different ideas. Some officers who were just desperately trying to break the trench warfare stalemate, you had tacticians looking at the catastrophic losses of previous offensives and realizing, you know, the old methods simply didn't work anymore.

3:02So on one side, you have major general Henry Tudor. Right. He was commanding the artillery of the ninth division and Tudor wanted to launch an attack relying heavily on surprise. He wanted to use a relatively new concept called silent registration alongside something called sound ranging. And the mechanics of silent registration are just brilliant because prior to Cambrai, if an artillery battery wanted to hit a specific target, say a pillbox or a crossroads, they had to fire practice rounds. They called it registering the gun. Right. Spotters would watch where those shells landed and the gunners would manually adjust their aim until they hit the target. But doing that for days across an entire front line completely broadcasts your intentions. It essentially tells the enemy exactly where you're going to attack. Guarantees, they will bring up reserves and man their machine guns long before your imptentry even goes over the top. So Tudor's proposition was to use mathematics and meteorology to bypass that entirely. Which was incredibly ambitious for 1917. Insanely ambitious.

4:04They were calculating the exact muzzle velocity of the guns, the weight of the shells, wind speed, air temperature, even barometric pressure. All done on paper. Right. And you combine that with sound ranging. Which is what? Exactly. It's using an array of microphones to capture the sound waves of enemy artillery and then triangulating their position using the speed of sound. Tudor believed if he used both of these, he could instantly paralyze the German batteries at the exact moment the imptentry advanced. No warning whatsoever. So that's the artillery side. But simultaneously, you have officers in the tank corps, particularly JFC Fuller, who were desperate to prove what massed armor could do. Because prior to this, tanks had only been used in small numbers. They often just got bogged down in the mud of places like passion down. So Fuller is looking for a firm, chalky ground. He wants to unleash a concentrated fleet of tanks to basically raid the enemy lines, crush

5:04the wire, and cause absolute panic. And this is where General Julien Bing comes in. He's commanding the British Third Army and he sees the potential in both Tudor's artillery plan and Fuller's tank raid. So he decides to combine them into one massive, full-scale offensive. But the logistics of combining these elements, I mean, they're orchestrating a symphony of new, highly temperamental technologies here. Oh, absolutely. Yeah. For example, to help the tanks cross the battlefield, the artillery heavily utilized the Noble 106 fuse. The wire cutter fuse. Exactly. As earlier in the war, high explosive shells often just buried themselves deep in the mud before detonating. Which creates massive craters. Right. And those craters essentially became impassable tank traps. The tanks would just fall in and get stuck. But the Noble 106 was a highly sensitive percussion fuse designed to detonate the instant it touched anything, even a single strand of barbed wire. So it effectively acts as a giant wire cutter that sweeps the ground clear without destroying

6:04the actual terrain the tanks need to drive over. It was crucial. Yeah. But it wasn't just artillery and tanks being also brought in the Royal Flying Corps. The RFC. Right. In the weeks leading up to the battle, RFC squadrons began training specifically for close air support and ground attack tactics. Which again is so modern. Very. They were given detailed assignments to fly at incredibly low altitudes. Yeah. We're talking sometimes just 50 feet off the ground. Wow. Just flying right over the mud to attack trenches, shoot up supply convoys and bomb enemy airfields as the infantry advanced. Which introduces an entirely new layer of complexity. What's fascinating here is that this is the birth of industrial modern combined arms warfare. You're looking at predicted artillery fire, sound ranging, mass armor, infantry coordination and close air support all attempting to operate in unison. I mean, put yourself in the shows of a British stack officer in November 1917 trying to coordinate this. You are dealing with primitive biplanes trying to fly through the trajectory of your own

7:06artillery shells. Yeah. You have over 400 mechanical tanks that are notoriously prone to engine failures, carbon monoxide leaks and slipping their tracks. All of them moving at the speed of a walking mat. Right. You have over 1,000 artillery pieces being aimed blindly using paper mat and you have to move all of this men and material into position at night in total secrecy right under the nose of the German centuries. The sheer friction of war suggests a dozen ways this could have failed before it even began. But the meticulous preparation largely helped. It did. The German command had some vague intelligence from prisoners that an attack was being prepared and the new tanks were in the sector. But they completely misjudge the scale and the timing. Which brings us to dawn on November 20th. The first day. At exactly 620 AM, 1,000 and three British guns open fire simultaneously. There is no preliminary bombardment lasting for days. It is just instant devastating shock action. And the predicted fire and sound ranging work beautifully.

8:08They immediately suppress the German artillery and blanket the observation posts and tear gas and smoke. And behind that smoke, a creeping barrage begins to advance. Which requires absolute terrifying synchronization. For those who don't know, a creeping barrage is the literal wall of high explosive shells advancing across the battlefield at a precise mathematical rate, usually about 50 yards per minute. So the infantry has to walk right behind it. Six divisions of advancing British infantry had to walk directly behind this moving wall of fire. If they walked too fast, they were obliterated by their own artillery. And if they walked too slow. The barrage would move past the German dugouts, giving the defenders time to run of the stairs from their bunkers and man their machine guns before the British arrive. It's a razor-thin margin for error. But pressing forward right alongside the infantry are 437 Mark IV tanks. These are 30-ton, rhomboid monsters. Prushing the belts of barbed wire that were supposed to be completely impassable. The psychological impact on the German defenders in those opening hours was staggering.

9:10Absolutely paralyzing. By midday, the British had ruptured the Hindenburg line, penetrating up to 5 miles deep in certain sectors. And to understand the magnitude of a 5 mile advance in 1917, you'd just have to look at the previous offensive. At Passionale, the British spent three months fighting through a nightmare of mud, suffering hundreds of thousands of casualties to advance roughly the same distance. Three months versus six hours. Exactly. At Canberra, they did it in six hours, capturing over 4,000 prisoners with a fraction of the casually rate. It was a tactical triumph that sent shockwaves all the way back to London where they literally rang the church bells in celebration. But a breakthrough on a map doesn't mean the reality on the ground is flawless. The friction of using all this untested, heavy technology immediately started to show. The machine which just wasn't reliable enough yet. No. One of the most vivid examples involves the 20th Division's advance toward the Canal de Saint Quentin at Mezzanierre. They actually managed to secure a crucial bridge spanning the canal, which is a huge prize

10:13in an advance. Massive. But when a Mark IV tank, the specific one was named Flying Fox Stasic, when it attempted to cross, the Mezzanierre simply couldn't handle the 30 tons of unspronged weight. It wasn't built for tanks. Right. The bridge spectacularly collapsed, taking the tank down with it into the canal and completely severing the route for the cavalry and remaining armor to exploit the gap. So infrastructure failure was one major vulnerability. The other was the assumption that the tanks were invulnerable to standard field artillery. Which they learned the hard way at Fleskierre. Yeah, at the village of Fleskierre, the British armor ran into a wall of resistance that halted the entire center of the advance. And for decades, a myth circulated about a lone German gunner at Fleskierre. Oh, right. The lone gunner. Yeah. The story was about a single heroic artillery officer who stood by his field gun after his crew was killed and just single-handedly knocked out a wave of British tanks. It's a very romantic cinematic image, but the tactical reality is far more interesting

11:14than the myth. The tanks weren't stopped by a lucky lone wolf. They ran headlong into field artillery regiment 108, commanded by Major Krebs. Right. And this wasn't just a standard artillery battery. This was a unit that had specifically trained in anti-tank tactics. Because they had faced French armor earlier in the year, right, during the Nevele offensive. Exactly. They understood the vulnerabilities of the Mark IV tank. So they pulled their field guns out of the standard indirect fire pits and positioned them for direct line of sight fire. They were basically using them as giant sniper rifles against the tanks. Pretty much. By holding their nerve and waiting until the tanks crested the ridge of Fleskierre, they utilized their specialized training to devastating effect. They knocked out nearly 40 tanks in that sector alone. Wow. It just proves that even when confronted with a revolutionary new technology, a well-trained, adaptive unit can develop countermeasures very quickly. And the broader statistics from the end of that first day really highlight the fragility

12:14of the 1917 tank fleet. Out of the 437 tanks that rolled out at dawn, 179 were completely out of action by nightfall. That is a massive attrition rate. It is. But the breakdown of why they were out of action is the crucial part. Only 65 of those tanks were actually destroyed by German artillery fire. So what happened to the rest? Maybe one of them suffered catastrophic mechanical breakdowns, blown engines, snap drive chains, and 43 of them simply ditched. Ditching was a constant hazard with early tanks. If a tank slid sideways into a wide communication trench or high-centered itself on a massive tree stump, the tracks would just spin in the mud. They had no traction. Right. And without dedicated recovery vehicles, the bitch tank was essentially just a concrete pillbox, completely useless for an advancing offensive. So while the initial shock broke the line, the mechanized spearhead had effectively blunted itself through sheer mechanical attrition within 24 hours.

13:16Which fundamentally changes the geometry of the battlefield over the next week. The element of surprise is gone. The tanks are mostly broken down or destroyed. And the battle degrades into the exact kind of horrific attrition it was designed to avoid. From November 21st to November 28th, the focus of the fighting narrows onto Berlin Ridge and Berlin Wood. Which was this dense, heavily contested high ground that dominated the battlefield. The fighting in Berlin Wood was just a brutal, close quarter slog. The infantry was exhausted, having far outrun their supply lines during that initial five-mile sprint. Taking and holding that wood came at an appalling cost. Just to give a sense of scale, the 40th division sustained over 4,000 casualties in just three days of fighting among those trees. And the German command rapidly poured reinforcements into the sector. They didn't just plug the gap. They concentrated a terrifying amount of artillery on the new British positions. On November 28th alone, German batteries fired over 16,000 shells into Berlin Wood.

14:1616,000 in one day. The British troops were essentially sitting in a newly formed salient, a bulge protruding into enemy territory, which meant they were taking fire from three different directions. So by the 28th, the British offensive is officially halted. The troops were ordered to string wire and dig defensive trenches. But the Germans were not content to simply stabilize the line. They assembled 20 divisions in the area and prepared a massive counterstroke. On November 30th, they launched the largest counterattack against the British Expeditionary Force since the opening months of the war in 1914. Here's where it gets really interesting. As the Germans didn't revert to the old methods of human wave attacks either, just as the British had innovated with tanks and predicted fire, the Germans unveiled their own tactical revolution. Infiltration tactics. Right. Often referred to as hutier tactics, heavily supported by an artillery doctrine orchestrated by Colonel Jarg Bruckmiller. Bruckmiller's approach to artillery was entirely different from the week-long bombardments of the past. He designed short, incredibly intense hurricane bombardments.

15:20No more pounding the dirt for a week. Exactly. But more importantly, he mixed high explosives with gas shells, specifically targeting the British artillery batteries and command posts in the rear to blind and silence the defensive guns. In the moment, this brief bombardment lifted the infantry attacked, but not in long, slow-moving lines. They used specialized dorm troops. These were heavily armed, fast-moving squads leading the assault, and their orders ran completely counter to traditional military thinking. If a storm-tribbed squad encountered a heavily defended British pillbox or a stubborn machine-gun nest, they didn't stop to lay siege to it. They completely bypassed it. They flowed around the strong points like water around it rock, pushing as deep and as fast as they could into the British rear areas. Because the objective was to sever communication lines, overrun artillery batteries before they could deploy, and just cause widespread panic. And it worked. The speed of this infiltration on the southern flank of the salient was unprecedented.

16:22They covered miles of ground in a matter of hours, collapsing the British defense from the inside out. The chaos in the rear was absolute. British supply clerks, cooks, and engineers suddenly found German stormtroopers appearing behind their lines. There's this crazy detail about Brigadier General Berkeley Vincent. He literally had to fight his way out of his own headquarters. He was grabbing retreating stragglers on the road, just to try and string together a makeshift defensive line to protect the vital supply routes. Up on the northern flank, a Berlin ridge, the British defense was slightly more structured, but equally desperate. The units holding the high ground were subjected to relentless assaults. The volume of fire required to hold the line was staggering. Records detail one group of eight British vickers machine guns that fired and astonishing 70,000 rounds to repel the German infiltration units. 70,000 rounds from eight guns. Imagine the physical toll of that. Those water cooled machine guns would have been boiling off their water jackets constantly.

17:23Crews were desperately swapping barrels and feeding canvas belts of ammunition for hours on end. The sheer volume of lead in the air is difficult to even comprehend. But through a combination of this desperate defense, the arrival of a few reserve tanks and counterattacks by the guards division, the British managed to hold the northern ridge. But the southern flank had been completely caved in. Yeah, the ferocity of the German counterattack forced the British high command to recognize that holding the entire newly captured salient was tactically impossible. They were too exposed. So in the first week of December, the order was given for a partial withdrawal, which brings us to the final map on December 7th when the battle officially ends. And when you look at that map. If you overlay the front line of November 19th with the front line of December 7th, it is essentially a draw. The British retained a strip of captured territory in the north, including the villages of Heavencore, Rebrocore, and Flaskier. But to the south, the Germans had not only recaptured their lost ground. They had actually pushed past the original start line, taking territory around Gondelieu.

18:27So the territorial exchange was negligible. But the human cost was immense. Calculating exact numbers for World War I battles is notoriously difficult. Due to how different armies categorized the wounded, but the data is stark. Right. British casualties are estimated to be between 44,000 and 75,000, depending on whether lightly wounded soldiers treated at local casualty clearing stations are included. And the official German medical reports compiled later listed over 54,000 casualties for the Cambry operations. Over 100,000 men killed, wounded, or captured for a map that barely changed. So what does this all mean? If the front line ended up right back where it started, and the human toll was just as horrific as previous battles. Why is Cambry considered a masterclass in the blueprint of modern warfare? If we connect this to the bigger picture, Cambry completely shattered the strategic paradigms of the First World War. Also. Well, for three years, the assumption was that a heavily fortified trench system, defended

19:28by machine guns and deep wire, could only be breached through months of attritional bombardment and massive loss of life. Cambry proved definitively that surprise, combined with the synchronized application of armor, artillery, infantry, and air power, could crack the strongest fortress in the world in a matter of hours. It proved the concept was viable, even if the machinery of 1917 was still too fragile to sustain the momentum. And the psychological shock to the German high command was profound. Following the battle, Crown Prince Ruprecht observed the new reality of the battlefield. Be stated, wherever the ground offers suitable going for tanks, surprise attacks like this may be expected. That being the case, there could be no more mention, therefore, of quiet fronts. No more quiet fronts. Which completely changes the economic and logistical reality of the war. After Cambry, the German military had to constantly look over its shoulder. They were forced to adapt. Yes. They were forced to divert immense amounts of scarce steel, manufacturing capacity, and manpower

20:31into producing anti-tank rifles, armor-piercing ammunition, and constructing wider trenches, specifically designed to stop tanks. And every ounce of steel poured into an anti-tank obstacle was an ounce of steel that couldn't be used to build a U-bow or an artillery piece. Exactly. The mere existence of massed armor stretched the German war economy to the breaking point. And the legacy of that paradigm shift is still highly visible today. The Royal Tank Regiment of the British Army celebrates Cambry Day annually, marking the moment they proved massed armor could change the world. And the commemoration extends globally, too. Right. The Indian Army's second Lancers celebrate Cambry Day every December 1st, specifically honoring Lance Defadar Gobin Singh, who was awarded the Victoria Cross for extraordinary bravery during the battle. It's a powerful reminder of how vast and diverse the forces engaged in this conflict truly were. Cambry represents the painful, messy, but undeniable transition into modern warfare. The British demonstrated how to break a line using combined arms and technology.

21:32And the Germans demonstrated how to counter attack using speed, bypass tactics, and decentralized command. The lessons learned here directly lay the groundwork for the armored blitzkriegs and mobile warfare doctrines that would dominate the Second World War just two decades later. To wrap this up, the Battle of Cambry started as an experiment. It was a theoretical test to see if mathematical artillery and a fleet of clumsy, temperamental metal boxes could do what millions of artillery shells and millions of men had failed to do for three years. And despite the mechanical failures, the tactical blunders, and the brutal counterattack, the experiment fundamentally worked. It changed everything. It did. When you look closely at Cambry, you see millions of men being forced to completely unlearn everything they knew about fighting. They went from horses, sabers, and static trenches to coordinating close air support, mechanized armor, and highly fluid infiltration tactics in the span of 36 months. It's an incredible leap. It makes you wonder, when you look at the incredibly rapid technological leaps happening

22:34in our own lives right now, how long does it take for our old strategies in business, in society, or in our personal lives to become totally obsolete? And more importantly, when the equivalent of a new tang rolls onto your battlefield, are you going to stubbornly dig a deeper trench or are you going to fundamentally change the way you fight? That is exactly the kind of question we love to leave you with. Thank you for joining us on this deep dive into Cambry. Keep learning, keep looking at the forces shaping the world, and above all, keep questioning the old ways of doing things. We will catch you next time. You're listening to a podcast right now, driving, working out, walking the dog. If you're in a podcast, chances are you have something to say too. With RSS.com, starting your own podcast is free and easy. Upload an episode and we distribute it to Apple podcasts, Spotify, Amazon Music, and more. Track your listeners, see where they're from, and start earning from ads just like this. If you've been thinking about starting a podcast, this is your sign. Start your new podcast for free today at RSS.com.