Can You Make a Sherman Tank Float?

to rip apart any boat trying to land. Verdant green hills rise behind the beach, and hid amongst their folds are trenches, machine gun nests, and cannon emplacements. This is Hitler's Atlantic War, part of the three thousand mile chain of fortifications built from the Spanish frontier to the Arctic tip of Norway. The Nazis have sunk vast sums of money billions into the project, with just one aim to

stop any Allied invasion dead in the surf. The battle chips offshore are hammering these fortifications with their big guns. But while the Germans are many things, they're not stupid. Their pillboxes are angled to make them impervious to these shells, whilst still giving the defenders inside a perfect sideline to shoot left and right along Omaha Beach. Each hour is appro and when the first American troops storm ashore, they'll

be at the mercy of this withering barrage. Running across hundreds of yards of open sand under German fire will be a task as murderous as anything seen in World War One. The death toll could be enormous, and that's where an unlikely secret weapon comes in. We're aboard a landing craft with men of the seven hundred and forty

first Tank Battalion. These tank crews are scheduled to hit the beach ahead of the infantry, with orders to train their cannon on the German defenders, knocking them out before they can annihilate the poor foot soldiers following behind. The seven hundred and forty First tanks won't be arriving by landing craft, though, in a cunning twist, these tanks will swim into battle all by themselves. The Germans have never

seen anything like it in the water. Our tanks look just like small boats, says tank crewman Private Bill Murkert. Will be a big surprise for the Germans. When we come out of the surf. These special tanks are able to swim thanks to a set of propellers and a flimsy looking canvas screen allowing them to float. It's taken a huge effort to make these Sherman tanks seaworthy, but ally generals think it's the best way to reduce bloodshed on the invasion beaches. But can you ever really make

a thirty three ton tank seaworthy? Even by the standards of the English Channel. D Day June sixth, nineteen forty four is something of a washout. It's the word summer weather in memory and more akin to the storms of winter. The sea's pretty heavy. Notes Bill Murkert brought his d D tank. He never practiced in this kind of weather. But more than three miles from shore, a yellow signal flag still goes up. The landing craft drops its ramp

and builds. Sherman tank platters forward and into the waves. I'm Tim Harford and you're listening to another cautionary tale. The tank was a defining weapon of World War II. German panzas had defeated Poland in the first weeks of the conflict, then rolled across Western Europe. These clanking, clattering guns on tracks that bested the mighty French army and

thrown the British back into the sea. The blitzquig tactics of Hitler's tank commanders had taken them to the gates of Moscow and had very nearly swept the British out of North Africa. It was all very annoying for Prime Minister Winston Churchill. During the First World War, he had been in charge of the Royal Navy and had diverted a fraction of its immense budget to fund the building

of so called land ships. These weren't ships at all. Rather, they were primitive tanks, and thanks to forward thinkers such as church the British had enjoyed an early lead in the development of armored warfare, but this foundational work was regrettably squandered at war's end. The defeated Germans were keen to learn all about the tanks that had helped seal their fate, but the British officer class preferred to return to a more traditional way of waging war on involving

stirrups and swords and big beautiful horses. That neglect has robbed us of all the fruits of this invention, lamented Churchill. In the darkest days of World War II, these fruits have been reaped by the enemy with terrible consequences. Churchill adored adventures and adventurers. He loved bold schemes and unorthodox thinkers almost to a fault. Angered that his army had been left behind in the tank ray, the new Prime Minister decided to back his hunch and promote one Percy

Cleghorn Stanley Hobart. Hobart was a fifty six year old lance corporal in the Home Guard, a ragtag army of old men and teenage boys who guarded against the Nazi invasion in their spare time, occasionally armed only with carving knives tied to broomsticks. Of course, Hobart hadn't always been a lowly lance corporal. He had been a major general

in the regular Army and a fanatic about tanks. He wrote about them, he talked about them, and finally badgered his superiors into giving him command of a new tank brigade to test his theories. The German high command rather admired his work, copying his ideas so much so that after one panzer exercise. It was said to have raised a Champagne toast in his honor to Hobart. Hobart's fellow British officers, however, found his dedication to armored warfare rather tiresome.

Hobo was drummed out of the army, and his many enemies in the General Staff fought fiercely any campaign to bring him back. Winston Churchill was not, however, a man to accept defeat, so he wrote to the Chief of the Imperial General Staff, this is a time to try men of force and vision, and not to be exclusively confined to those who are judged thoroughly safe by conventional standards. Will you kindly make sure the appointment is made the

earliest moment. Further plots were hatched to have Hobart pensioned off, but he survived them all and eventually found himself in charge of a unit that was pretty experimental, even by his standards. The seventy ninth Armored Division was unique. Its role was to develop and deploy on the battlefield tanks capable of quite remarkable feats. Feats all intended to allow the Allies to crack Hitler's Atlantic Wall and invade Europe.

If there was a minefield in the way, Hobart had a tank which was fitted with a rotating drum of chains to flail the ground and clear the explosives. If the Nazis had dug a deep anti tank ditch and the seventy ninth could bring up a tank carrying its own section of bridge, Hobart had tanks for every job imaginable, able to blast and burn and generally overcome anything Hitler's Invasion Beaches had to offer. These vehicles became known as

Hobart's Funnies, and of course included a swimming tank. The idea of a swimming tank had been floating around for decades, but under a cloak of secrecy, the British now perfected the concept well almost To stay afloat, DD or duplex drive tanks had to displace a weight of water greater than their own weight. To achieve this buoyancy, a tall canvas screen was erected right around the vehicle, held in place by metal struts and inflatable rubber tubes. Even so,

the vehicles still rode worryingly low in the water. To our eyes, DD tanks seem precarious, even a little mad. The Shermans looked a bit like they were hiding at the bottom of a big canvas bucket, but they seemed to have impressed the British top brass. Since D Day was to be a combined Anglo American effort, Churchill and Hobart needed some American buy in. Hobart had overseen many thousands of practice launches of swimming tanks with just as single sinking, so he set up a demonstration for his

American counterparts. The US generals turned their noses up at Hobart's other funnies, his flameed ower tanks and bridge layers, but they rather liked the DD. They were fearful that if a German shell struck a landing craft on D Day, then four tanks would be sunk in one go. Swimming tanks,

being harder to hit, seemed to solve this problem. The American generals instructed Washington to approve the immediate construction of hundreds of the contraptions and gave them a triple A priority rating at the same rating as the atomic bomb, a sign of the high hopes many had for the DD tank and the importance they placed on it. Now that swimming tanks were rolling off the production lines. Training

could begin in earnest. Exercise Smash was scheduled for April nineteen forty four and would be a rehearsal as close to battle conditions as possible, complete with the firing of live ammunition. Under the gaze of Winston Churchill, General Eisenhower and King George. A force of DD tanks swam towards a deserted English beach. We knew we weren't going to

make it, said one of the tank commanders. Wins in the English Channel that day were reaching force four and the waves were a meter high, causing the commander to eye the canvas screen around his tank nervously. A great wave crashed over the top, he said, and we sank to the bottom. Six tanks were lost on Exercise Smash, and six men drowned. A seventh tank got stuck on a sandbar and was abandoned by its crew. It then

refloated and began drifting out to sea. Fearing it might float off and be discovered by the Germans, the Royal Navy blew it to pieces in the choppy waters of the Channel. It was no small thing to turn a tank into a boat, nor was it straightforward to turn soldiers into sailors. Cautionary tails will return shortly on D Day, the seas off Omaha Beach were running, if anything, even higher than they had during the ill fated exercise smash.

Following those sinkings in April, the US Navy thought it had been agreed that the DD tanks would only be launched weather permitting, and that the tank crews would heed the advice of its sailors before venturing out into the winds and the waves and the wicked tide. Sadly, it was never set out what happened if the soldiers and

sailors disagreed. Aboard the ships carrying the DD tanks of seven hundred and forty First Battalion, The most senior sailor thought it was obvious that the sea was too choppy, but the army officers looked at the same rolling waves and decided they'd take the risk. Everyone from Churchill down nearly thought the DD tank was a splendid idea, and after all the trouble and training, were the officers of the seven hundred and forty First really going to give up now because of a few waves. They had a

job to do. On other D Day beaches and even further along Omaha Beach, Naval commanders were successfully arguing that it was folly to launch the DD tanks, so their landing craft were taking the armor right up to the shore, but Private Bill Murkert and his comrades in the seven hundred and forty first were ordered to set their propellers spinning and swim the three miles or more to shore. The swell was really big. Bill remembered. One moment you'd ride a crest and get a view of the beach.

The next he'd be at the bottom of a trough and just see water all around you. The D Day plans were meticulous, calling for Bill's tank to land at a specific spot on Omaha Beach. In calm weather, this would have been most cinch, but against the seas that day, even an experienced sailor would have struggled. The DD tanks soon found themselves being swept off course, so the crews desperately steered their craft to fight the wind and currents.

But this was a mistake no seasoned mariner would have made, because by doing so, the tanks only exposed their vulnerable sides to the butting waves. The struts holding up the canvas screen started to buckled. Bill recalled he had been standing atop his Sherman. I was bracing a struck, but I was in no doubt we were in serious trouble. Was soon proved correct. We were the first tank to sink and went straight down with a big gulp, dragging a couple of guys down with it. Twenty six other

tanks soon followed Bills to the bottom. Some soldiers bobbed free in the chilly waters, but others sank with their vehicles. Bill Murkert dragged himself into a half inflated life raft to await rescue and reflected on the squandering of nearly half of the entire DD force. That lost firepower could have made a big difference to the soldiers fighting on Omaha,

he concluded. Nineteen year old Sergeant Ben Franklin was one of those soldiers wading through the surf and sorely missing the support of a Sherman tank and machine gun bullets were hitting everywhere. Were scared of death, and there was nothing I could do but duck under the water when they came close and hold my breath as long as I could. The young infantrymen reached dry land, but with so few tanks to blast the German pill boxes and machine gun nests, he faced a daunting sprint up the

exposed beach. In his bunker on the hill above, German private Franz Gockle was able to train his machine gun on gis like Ben Franklin, safe from attack by a Sherman. The Americans had a lot of beach to cross. As they swarmed towards me. I opened fire. The Americans fell, and many never stood up again. I don't know how

many I killed. The lack of armor on that section of beach is blamed for the invasion there grinding to a halt, with the generals out to sea, pondering the idea of abandoning Bloody Omaha altogether and sending reinforcements to beaches where their tanks had more successfully cut a swathe through Hitler's defenses. That didn't happen. The attacking troops on Omaha Beach slowly but surely knocked out one German strong

point after another. The Atlantic Wall had cost Nazi Germany a fortune to construct, but had held up the Allies for a few hours at most, so the sinking of the seven hundred and forty firsts DD tanks didn't lose the Allies the Battle of Omaha Beach. That fight was one but that are terrible and perhaps needless cost in lives.

One wonders why the concept of amphibious tanks was ever serious the entertain in the first place, let alone given top secret triple A priority, soaking up resources and manpower badly needed elsewhere. Here's the thing about DD tanks, historian John McManus told the We Have Ways podcast, they solved a problem that didn't really exist. We had already worked out how to bring tanks ashore. He's right. An official Army report said the DD tank was not satisfactory for

the purpose intended. It noted that up and down the D Day Beaches, the Navy had successfully delivered tanks where they needed to be without significant losses to German artillery. The fear that the fleet of landing craft would be decimated proved unfounded. It was ironically the swim in that wiped out many of the vital tanks. Zach Morris, author of When the Beaches Trembled, notes that in the war against Japan and the Pacific, where Incidentally, DD tanks had

been rejected. The US Navy had instead equipped small landing craft with tank cannon. Thus armed, they could sail close to shore and bring those guns to bear on the enemy. Morris says the D Day planners were thinking, how can we make a floating tank? They were asking the wrong question. It should have been what can we take that already floats and make it into a tank. This all rather

reminds me of milkshakes. Yes, you heard that correctly. Harvard Business School professor Clayton Christensen used the example of milkshakes to illustrate how people often set up off down the road to solve the wrong problem. Christensen told of a fast food chain wanting to boost its milkshake sales. A sophisticated research project was launched to find out what customers looked for in a shake, should it be cheaper, or chunkier or more chocolatey. The recipe was then tweaked accordingly,

yet still sales and profits stayed flat. Puzzled, the fast food firm brought in one of Christensen's fellow researchers, who stood in an outlet and asked himself a strange question. It wasn't what flavor do people like nor how much do they want to spend? Instead, he asked what are customers hiring their milkshakes to do. The researcher noticed that half of all milkshakes purchased in the mornings by loan

commuters who bought no other products. Quizzing these customers, he found that they had stopped in before their long drives to work. They were hiring the shakes to fill their stomachs for the next few hours, give them something to do as they drove, and all in a convenient package that would fit in their car's cup holder. Bagels, bananas or doughnuts weren't nearly as easy to consume at the wheel,

and besides, they were guzzled down too quickly. The company had wasted time and money on altering the taste or cost of its shakes, when what it needed to do was make the drinks more attractive to commuting motorists. They should have formulated and marketed a breakfast drink a morning milkshake. As Dawn Norma and the author of the Design of Everyday Things, says, a brilliant solution to the wrong problem

can be worse than no solution at all. DD tanks might have looked a bit rickety, but they were brilliant too. A tank able to ride the waves then rise up onto an enemy held beach to begin blasting away clearly impressed everyone who saw it trialed it solved the problem of how to make a tank float in calm seas, But was it solving the real problem at hand, how to invade Europe. Good designers never start by trying to

solve the problem given to them, says don Norman. They take the original problem as a suggestion, not as a final statement, and they don't try to search for a solution until they've determined the real problem of The DD tanks were ingenious and their crews were heroic, but in hindsight it's all too easy to see that DD tanks

were an unnecessary diversion. It's widely agreed that if only the seven hundred and forty first tanks had been landed on Omaha Beach in the conventional way, many soldiers' lives would have been saved. But that's not the end of the story. D Day was just the start of the invasion, and waiting in land was something more impenetrable and more deadly than Hitler's beach defenses. The soldiers leaving Bloody Omaha were about to enter a hellscape for which no ingenious

Sherman tank had been designed. Cautionary tales will be back. Adolf Hitler, ever, the lover of garish and gargantuan architectural projects, was convinced that the entire coastline of Europe could be made impregnable. If only enough concrete was poured, the lands he had conquered would become He decreed a festoon, a fortress. Field. Marshal Erwin Rommel, the man Hitler sent to oversee the

defenses in France, took her more realistic view. Hitler was living in vulcan cuckook sheim cloud Cuckoo Land if he thought the Atlantic Wall would prevent an Allied invasion. Touring the Normandy beaches before D Day, Rommeld quickly realized that the much publicized Atlantic was far less formidable than Nazi

propagandists would have the world believe. There were great stretches of coast where no fortifications existed at all, and many of the completed bunkers were equipped with a mishmash of weaponry and manned by substandard troops or foreigners from Russia or Eastern Europe fighting for the Nazis only under duress. Even had the fortresses of Hitler's ravings been real, many of his generals doubted the military logic of the whole

Atlantic Wall project. These bunkers would be pommeled from sea and air by the Allies, with the defenders trapped inside until the invading armies overran them and took them prisoner. It would be better to retreat inland, slowly, making the Allies spill blood for every foot they advanced. The Germans would be helped in this by a formidable defensive network stretching miles back from the coast, and for which they're not spent a penny. It was built not by German

engineers nor enslaved laborers. Instead, it had evolved over centuries thanks to Norman farmers and landowners. I'm speaking of the Bokage. The Bokhage was a patchwork of small fields divided by tall, thick hedgerows and deep sunken lanes. Such a landscape was easy to defend and a nightmare to attack. Coming to the first hedgerow, said one American soldier, we immediately saw

death and destruction in its most violent form. A couple of German machine guns cleverly positioned could cut anyone wandering into the fields to ribbons. Sherman tanks could have tipped the balance in the Alli's favor, but they simply couldn't move in the Bokhage. These hedgerows weren't made of concrete, but centuries of compacted dirt and a criss crossing tangle of roots. The next best thing. Even a thirty three

ton tank couldn't smash through them. The best a Sherman could do was drive up and over the embankments, but in the process they might fatally expose their vulnerable bellies to the enemy. One bitter two day battle saw the Americans advance just half a mile through the Bokhage, with more than four hundred tank crewmen killed or wounded in the process. According to one gi many American tankers fled the carnage. I saw dozens of them running like hell

for the rear. He recalled. Such panic is understandable. These American soldiers had trained for months for the invasion, learning how best to cross the beaches and neutralize the Atlantic Wall, but no lessons had been offered on how to fight and win in the Bokhage, and while much thought and effort had gone into the DD tanks and the other Hobart funnies, there was certainly no armored vehicles specially modified

to deal with these ancient Norman hedges. Although there had been some talk before D Day about hedgerows, said one American general, nobody anticipated how difficult they would be, so just a few miles inland from Omaha Beach, the advance ground to a halt. It had taken mere hours to break through the vastly expensive Atlantic Wall, but for week

after week, the Americans struggled to beat the Bokhage. America's mechanized army was at its best when performing great sweeping movements with speeding tanks and trucks and jeeps, but it had been slowed to a snail's pace and then stopped altogether. We're stuck, complained one tank crewman. Things are going very awry. The whole theory of mobility we've been taught of our racing across the battlefield has gone up in smoke. In

the dark maze of lanes and hedges. The death toll rose to an alarming level, and many of those untouched by bullet or shell left the battlefield with mental exhaustion so called battle fatigue, or simply lay down their weapons and deserted. It wasn't clear that anyone in command had the slightest idea what to do to break the stalemate. Why don't we get some saw teeth and put them on the front of the tank and cut through these hedges.

The assembled tank crews laughed at the suggestion. The men had been brought together to brainstorm a solution to the Brakhage problem, but few saw much merit in this suggestion by their comrade from Tennessee. Wait a minute, said staff Sergeant Curtis Cullin, defending the man. He's got an idea there. The twenty nine year old Cullin mouled over the problem. What kind of teeth could cut through a hedgerow that

had stood solidly for centuries? Steel teeth, presumably, But where was there a ready supply of sharp and hardened steel. Wasn't there plenty on Omaha Beach, suggested another member of the unit. The Germans, he pointed out, had littered the sands with so called check hedgehogs and Belgian gates, both

sharp steel obstacles intended to damage landing craft and vehicles alike. So, without seeking any higher authority, someone was sent back to collect these steel beams, and the process began to weld them to the hull of a sherman. Cullin and his comrades didn't know it, but they were engaged in something with today call workplace innovation. The concept encourages business owners to pay greater heed to the ideas of their workers, who, after all, see the problems their companies face day after

day and might come up with nifty solutions. Workplace innovation theorists promised that greater productivity and profitability can be achieved, but only of employees a given permission to experiment and a certain amount of space to manage themselves. That permission is often not forthcoming, which is why back in nineteen forty four, Sergeant Cullin kept his hedge cutting experiments a secret. He feared the ridicule of the higher ups, and maybe

those officers would be right to laugh. Now, armed with several sharp steel tusks, Cullin's tank slowly drove into a hedgerow, and as always happened, it began to rise and climb over the barrier, exposing its belly. It was lucky no German was nearby with the bazooka, so Cullin put his thinking cap on again. What if instead of driving slowly, the tank driver went full pelt. We've got something that

will knock your eyes out. Putting down the phone, the top us General in Normandy, Omar Bradley, hurried to Cullin's camp to see what all the fuss was about. He was greeted by a sherman that looked, for all the world like some metal rhinoceros. The tank backed off and ran head on towards a hedgerow, said Bradley. Its tusks bored into the wall and the tank broke through under a canopy of dirt. It had been a problem that had baffled Bradley's army for weeks, but here was the solution,

and it was, in the General's words, absurdly simple. There wasn't a second to lose us. Steel was gathered up from the beach and a team flown back to England to round up every available welder and their machines. Within days, five hundred rhino tanks were ready for action, and soon after sixty percent of all US tanks sported tusks with which to break through the bockage and spray the German defenders with bullet and shell. The stalemate was at last broken.

We could see that the Americans had learned how to break through, said one German soldier, now put to flight and retreating under heavy fire and constant air attacks. There would be much bloodshed to come, but the Americans were now trading lives for miles rather than meters gained, and some of that was down to the Rhino tanks, the brainchild of an ordinary soldier. The Rhino wasn't a product

of an arms company or a defense laboratory. It didn't have the long development time, the huge budget, and the triple A priority of the DD tanks. It was knocked up in the field from scrap metal by men who had an intimate knowledge of the problem they were facing. The Rhino was well and truly mcguivered. There was a little sergeant, said the Supreme Allied Commander Dwight Eisenhower. His name was Culin, and he had an idea. It seemed like a crazy idea, but this thing worked, and it

worked beautifully. The key sources for this episode were Norman D forty four by James Holland, Overlord by Max Hastings, Beyond the Beachhead by Joseph Balkowski, as well as Ryan Dilly's interviews with D Day veterans Bill Murkert and Ben Franklin. For a full list of sources, go to Timharford dot com. The Cautionary Tales as written by me Tim Harford with Andrew Wright, Alice Fines, and Ryan Dilly. It's produced by Georgia Mills and Marilyn Rust. The sound design and original

music are the work of Pascal Wise. Additional sound design is by Carlos San Juan at Brain Audio. Ben A. Dafhaffrey edited the scripts. The show also wouldn't have been possible without the work of Jacob Weisberg, Greta Cohne, Sarah Nix, Eric Sandler, Christina Sullivan, Kira Posey, and Owen Miller. Cautionary Tales is a production of Pushkin Industries. Do you want

to support the stories we tell on Cautionary Tales? If so, you can join my new Cautionary Club at patreon dot com Slash Cautionary Club for exclusive bonus episodes, newsletters, ad free listening, and other exciting perks. Alternatively, you can join Pushkin Plus on our Apple Show page for continued benefits from our show and others across the Pushkin network.