Dan Snow's History Hit - Fighting Hitler's U-Boats

Episode Date: December 18, 2023

The Second World War is remembered for its colossal battles in the air, on land and at sea. But perhaps the most terrifying were those waged UNDER the ocean, against an unseen enemy. By the end of 1941, cumbersome shipping convoys were Britain's only lifeline. Protecting them proved a difficult task, and German U-boats hunting in wolf packs sank merchant ships faster than they could be built. But into this loosing battle stepped the British naval officer and pioneer of anti-submarine warfare, Frederic 'Johnnie' Walker.Dan is joined by Angus Konstam, author of The Convoy, to take us through the remarkable story of Convoy HG-76, and explain how Captain Walker turned the hunted into the hunters.Produced by James Hickmann and edited by Ella Blaxill.Discover the past with exclusive history documentaries and ad-free podcasts presented by world-renowned historians from History Hit. Watch them on your smart TV or on the go with your mobile device. Get 50% off your first 3 months with code DANSNOW sign up now for your 14-day free trial.We'd love to hear from you! You can email the podcast at [e-mail] can take part in our listener survey here.

Hi everybody, welcome to Dan Snow's history hit, the Battle of the Atlantic. It ran from the first day of the Second World War pretty much to its last. It was the German attempt to starve, to blockade, to bring Britain to its knees by shutting off its ports to the trade of the world, by sinking ships, usually using submarines or U-boats. The first casualty of the Battle of the Atlantic was just a few hours after war was declared. The Athenia was sunk. They were sailing off to Canada. I once met a survivor, the last survivor of the Athenia. She was a young girl at the time.

She was placed in the life raft. Her parents stayed aboard very bravely as the ship went down. They were subsequently rescued by another ship and they were reunited months later. the ship went down. They were subsequently rescued by another ship and they were reunited months later. She showed me the little moccasin that the sailors on the rescue ship had made for her. She was just the first of so many people who experienced the horror of being sunk in the Atlantic. My grandpa, Robert Macmillan, was a doctor on a Canadian ship ploughing backwards and forwards across the Atlantic, to Halifax, to Belfast, Liverpool, down to Gibraltar. He told me about the extreme physical discomfort, the cold,

smashing through gigantic waves in a North Atlantic December storm. And that discomfort was mixed with boredom, plodding along at the speed of the slowest ship in the convoy, but also terror. The thought that at any moment, without warning, an explosion would rip a hole in the ship and it could sink, in the words of my grandpa's chief engineer, before he'd had time to put his foot on the first rung of the ladder. Many ships and many men were lost like that. And one of the worst points of the battle was 1941. Britain was in very real danger of losing the Battle of the Atlantic. The Germans were sinking British ships faster than they could be built. Enter one of the great heroes of Royal Navy history, of which there are many, let's be honest, but this one was quite unorthodox. He never commanded a big gun battleship. He never flew a plane at a daring raid on enemy targets. Instead, he was a man who transformed how Britain met the U-boat threat.

Frederick John Walker, aka Johnny Walker. If you go down to the banks of the Mersey in Liverpool at sunset, you'll see the bronze statue of a man in a naval uniform. It's one of my favourite statues in Britain. He's like a greyhound in the slip. He's lean, he's got his binoculars in hand, he's got his weight on his front foot. He's a hunter. He's a maverick. The sculptor has caught his essence beautifully. Johnny Walker was a troublemaker in peacetime.

He was argumentative. He was a headache. But in war, he was a game-changer. To tell me all about the innovations of Johnny Walker and how he won Britain's first convoy battle in the Atlantic, I'm joined on the podcast by Angus Constam. He's just written a book called The Convoy, HG76, taking the fight to Hitler's U-boats. And we're going to talk about just that. Enjoy.

T-minus 10. Atomic bombs dropped on Hiroshima. God save the king. No black-white unity till there is first in black unity. Enjoy. Angus, great to have you back on the podcast. Let's take the end of 1941. Up to that point of the war, what's the balance looking like? How is Germany's campaign to try and blockade Britain using its U-boats? The U-boats were remarkably successful by that stage of the war. Vice Admiral Dunitz, the supremo of the U-boat part of the Kriegsmarine, was fighting what he saw as a tonnage war.

And essentially, that boiled down to sinking more Allied merchant ships than we could build. He was doing remarkably well at it. And by the autumn of 1941, it was looking pretty grim for the British. And if this continued at that rate, the chances were that unless something drastic happened, such as America entering the war, we would actually run out of carriers. And these were the things that are taking the vital supplies that Britain needed to stay in the game, not just food, but also raw materials like iron ore. So it was a vital lifeline, and it was under grave threat. So the German submarines were able to sink more merchant ships, more freighters than

the British economy was able to produce. That's right. British and Canadian too, they were building ships too. But the trouble was, we also didn't have enough escorts. Early in the war, they were even poking fun at it, the merchant crews, because here comes the escort. It's like a barge and a rowing boat being sent to us. And Angus, we should say the escort is what the Royal Navy sends along to protect this convoy, a grey ship armed, hopefully with depth charges and a gun on the front. And you think, right, we're being escorted by the Navy here. And they weren't up to standard. Right. Early in the war, they were keeping ones back because of the threat of invasion.

So a lot of escorts, small warships, destroyers and below were being held back because of the threat of invasion. So a lot of escort, small warships, destroyers and below were being held back because they might be needed in the channel. So there were very few, but by the middle of 1941, a large number of things like corvettes, you've all seen the Cruel Sea, the film, and that's a corvette, these small things that look like a fishing boat, but armed with a gun at the front and depth charges. So they helped plug the gap. So by late 1941, we had just about enough escorts to do the job, but it was still touch and go. And the U-boats were still on a roll in terms of sinking. We were finding it very hard to sink U-boats while they were finding it very easy to sink merchant ships. Now, Angus, just explain to the layperson, why was that? These German submarines,

is it because they can creep in undetected and can get to within torpedo range and then make their escape? What is it about these submarines that was so potent? The U-boat wasn't a particularly great weapon in that it was slow once it was submerged. Its weak point was it could really go no faster than convoy when it was underwater, about seven to eight knots. But on the surface, it could do about 17 or 18. So it could overtake convoy and lie in wait for it. So the way they operated was to attack at night. Under cover of darkness, at the time, British radar wasn't really good enough to detect a U-boat on the surface with any guarantee of

accuracy or of success. So they were able to make an attack and then nip away on the surface at speed before the escorts, the pitifully few number of escort warships guarding increasingly large large convoys, was able to deal with it. What happened was that by the end of 1941, radar and ASDIC, what the Americans call sonar and we later call sonar, were improving. And we were starting to bridge that technological gap. So it became marginally easier to detect your boats. It becomes marginally easier to detect them, but it also was pretty easy to detect where the convoys were going, right? The convoy routes were reasonably predictable, they were quite slow moving, and these highly trained professional German crews could just pick off the odd limping gazelle from the convoy, could they? That's exactly it, Dan. The convoy,

for instance, the one I wrote about, takes the best part of two and a half weeks to get from Gibraltar to Liverpool. Once crossing the Atlantic, obviously taking even longer. And they're often doing very little more than seven or eight knots. So they're chugging along constantly under the risk of attack. But the Germans know where to go to some extent through a couple of things. some extent through a couple of things. One is radio direction finding, in that they're able to locate convoys through signals, radio signals being sent. So they have listening stations ranging from the south of France to the north of Norway that are listening for allied radio communications at sea, and they help triangulate where that convoy might be. There are other forms

of intelligence. For instance, the Abwehr in Gibraltar, when we're speaking about the Gibraltar convoys, were sitting in neighboring Algeciras with binoculars, basically able to phone the German embassy in Madrid saying, right, the convoy has just left, and so we can start massing for the attack. The other thing was, closer to home, you had land-based air reconnaissance. These four-engine Focke-Wulf Condors were immense bombers that could range about 1,500 miles out into the Atlantic and could stay in the air for extended periods, 12 hours or more. And once they found a convoy, they would shadow it, send back radio reports to headquarters. They would be passed on to Vice Admiral Dunitz in Lorient in Brittany, and U-boats would be vectored in to intercept the convoy. So they had a number of advantages

so that they could essentially marshal U-boats and wolf packs of U-boats on into the path of a convoy. And you've mentioned it a couple of times, but we should just clarify it. After the summer of 1940, we call these German U-boats and Kriegsmarine, the German Navy, but they're operating out of France and the Low Countries. They've got this wonderful, long stretch of coastline surrounding Britain, almost on two sides from Brittany all the way up to Norway. With lots of choice, the U-boats can pop into ports all over that and go into dry dock and get repaired and replenished. So it's a nightmare for the Royal Navy. That's exactly it. The spring and summer of 1940 were something of a disaster for Britain because not only the fall of France allowed the Germans to base their U-boats

instead of coming from Kiel and Willemshaven and those ports, which meant they had to go up through the North Sea to reach the Atlantic. Now they could be based in places like Lorient, Saint-Nazaire and Bordeaux, where they were right on the Atlantic coast, on the Bay of Biscay, a very short hop out into the hunting grounds of the Atlantic. And also if things went wrong, as you said, they had repair facilities there, but newly built U-boats still had to make the voyage there, but they could go as far as Norway and wait for the right opportune moment to break out into the Atlantic, start the patrol, and then return to, well, arrive in San Nazaire to reinforce the U-boats already there.

So they were being built up steadily throughout this phase of the war. And so the Navy are casting around for solutions. There is rapid advance of technology, radar, as you're saying, huge amounts of ships being built. Let's talk about the time, a career man would want to serve in concentrate and gunnery. That was the way forward. That was where promotion lay. But unusually, Frederick Walker, nicknamed Johnny by his friends after the whiskey, became a specialist in anti-submarine warfare. That was almost not really frowned upon, but it was seen as a backwater. But during the interwar years, he specialized in anti-submarine techniques. He became an expert in the use of and the potential of ASDIC, or sonar as we call it now. But also, he developed his own techniques, and he increasingly felt that the Navy were doing it wrong. Their aim was to make sure that a convoy

went from A to B without loss. And he said, that isn't really enough. We need to be more aggressive in our tactics. We need to send escorts out to hunt the U-boats. The best way to defend the convoy is to sink the U-boats that are shadowing it. So that was his whole thing. But he was essentially stifled during the war until the autumn of 1941, when he was given a small group of escorts to command, a couple of sloops and several corvettes. And they were sent out essentially as convoy escorts, but as the name suggests, they were a group and Walker trained them to operate together to actually hunt U-boats. So that was a kind of a breakthrough. He was emphasising teamwork, working together, using ASDIC as a way of hunting U-boats in a way which hadn't been done before.

And Angus, shouldn't we say he was lucky to be in a uniform at all during the war? He'd almost ended his naval career. Well, yes. Walker, during the last years of peace, kept on blotting his copybook by not kowtowing to the system, as it were. He was expected to be a social animal and smile nicely at cocktail parties. And he wasn't really prepared to do that. He was a thoroughgoing professional. And he wanted to prove his worth as an anti-submarine commander.

At one point, he was on the China station, where he was essentially driving a warship that was used as the Admiral's yacht. And that wasn't Walker at all. He wanted to be in the fight. So when the war started, he was still sidelined. He was helping Admiral Ramsey in Dover, and he was doing great work there. But it wasn't really where his skill set lay, which was helping fight and take on the German U-boats in the Atlantic. So in October of 1941, he's given this little motley collection of sort of eight very small ships, some of them hardly bigger than boats, really. And does he achieve success immediately? Is it clear from the get-go that we give this man the tools he needs and he can get the job done?

It wasn't really clear at the start. He didn't get a chance to shine. That came with his job of escorting convoy HT-76. However, the whole thing was that he spent his time with these ships and he didn't have them all together at one time. They were often taken away to do convoy escort duty on their own. So he rarely had a team of ships to work with. But when he did, he trained them and he emphasized teamwork. So when he was sent down to Gibraltar, they had the first success. One of the little ships he mentioned, a corvette called Marigold, sank a German U-boat, which was the first kill by the 34th escort group. And from then on, people started thinking, well, there might be something to this. So he was really the perfect

man for the job of escorting this convoy. And until then, he didn't really have a chance to shine. This HT-76 was the chance for him to prove that his system worked. Well, the war is not going particularly well. It's December 1941. Hitler is at the gates of Moscow. You've mentioned the Battle of the Atlantic is going badly. Tell me about HG-76. How many ships were in the convoy and what kind of things were they carrying? Well, during late 1941, Hitler overrode the wishes of Vice Admiral Dönitz and wanted to concentrate, instead of fighting in the mid-Atlantic, he wanted to attack the Gibraltar convoys. And this was really a political thing. He wanted to show support for his ally Mussolini. And Admiral Dönitz saw

this as a diversion from the main mission, which was his tonnage war. But he could still sink merchant ships. He was still in the game. These U-boats weren't wasted, but he didn't see it as part of his grand strategy. However, Hitler was adamant. So these U-boats were going to be concentrating on the Gibraltar convoys. They're the ones running from Gibraltar up to Britain. A lot of them arrived from North Africa and other ports, gathered in Gibraltar for the final run home. And convoy HG-76 was very typical, typical of hundreds of convoys in the war. But like I said before, she was carrying the goods Britain needed to stay in the war. And this ranged from things like iron ore to food. One ship, for instance, carried nothing but Spanish

onions collected in the Spanish port of Huelva. Spanish onions, I imagine, carried nothing but Spanish onions collected in the Spanish port of Huelva. Spanish onions, I imagine, are a luxury in wartime Britain. So that was a great morale booster. Others were carrying tomatoes from Tangier and this kind of thing. So this convoy was actually vital, not just in raw materials, but in foodstuffs and just to keep Britain going. It was made up of 32 merchant ships. They varied in size, quite small ones of about a thousand tons to ones of four or five thousand tons. And like any convoy, they were commanded by a convoy commodore, in this case, a retired vice admiral, Raymond Fitzmaurice, who didn't have a warship. He was put in one of the

merchant ships itself, the SS Spiro. And there was also a rear admiral, a retired rear admiral who had the job of vice commodore. But it was kind of run almost in naval lines, which didn't go down well at the start of the war with merchant naval captains. But by this stage, they'd all got on board and decided that they really had to tow the line if they wanted to survive. It was a matter of good convoy formation keeping and so on were part of the game by the stage of the war. So everyone had got more than enough practice at it to be good. So convoy HG-76 assembles in Gibraltar. It's due to leave on the 12th of December, but it's delayed a couple of days. But essentially, it fills Gibraltar Bay. Any of these convoys,

there was another convoy leaving the same day. Imagine Gibraltar Bay filled with shipping. For previous experience, how might they be feeling as they set out? I mean, if that convoy had attracted the gaze of a German wolf pack, I mean, how many ships could have faced the miserable end of sinking in the Bay of Biscay on a cold night? It wasn't a great prospect because a number of the other previous convoys had suffered very heavy losses, as many as 10 or 12 merchant ships, which when you've got 32 ships in the convoy, that's quite a high loss rate. But at this stage of the war, that was fairly common in these waters of the Atlantic between Britain and Gibraltar,

mainly because of Hitler's directive that these convoys would be specifically targeted by Dönitz and his U-boats. Now, what's Johnny Walker got? Is he in charge of the escorts? Is he in charge of this convoy's protection at this point? Yes, Johnny Walker has a number of escorts, small warships. The Corps is his own 34th escort group, made up of his own sloop, the Stork, another sloop and several small little corvettes. But they're reinforced for part of the voyage by a number of destroyers and escort destroyers and other small warships, basically cobbled together from various places just to reinforce this convoy. So a lot of these are only there for the first few days of the operation. They are pulled back and have first few days of the operation. They are

pulled back and have to return to Gibraltar. Some of them have been diverted from other convoys. So he has a command based around his own core ships, but it's increasingly reduced as the convoy continues on. When he leaves Gibraltar, he's got air cover. Their search aircraft are sent out. They're actually small hunting groups are sent out from Gibraltar looking for the wolf packs that they expect to be gathering. So the Navy is doing as much as it can to protect the convoy. But once it heads out to sea, it's entirely up to Walker and Vice Admiral Fitzmaurice, the convoy commodore, to keep them out of danger. Right. Well, that's the Allied convoy in's escorts. What's ranged against it? What's Dönitz and his U-boat command going to send out? Right, Dönitz, at this point,

knows the convoy is leaving, or is about to leave, thanks to spies observing it from Algeciras on the edge of Gibraltar Bay. He also has spies in places like Tangiers and Cadiz, ready to report ships sailing. He has a number of U-boats stationed off Gibraltar on its seaward approaches, on its Atlantic approaches. He also has these reconnaissance aircrafts. He's aware a convoy is about to sail, so he sends out a wolfpack, which he codenames Sea Rubber, or Sea Rouber, which means sea rubber or pirate. So Wolfpack Pirate is ordered to gather off Cape St. Vincent at the bottom left corner of Portugal and lie there and wait, ready for when the convoy sails. It will then intercept it and start attacking it. And as the convoy heads north, Dönitz intends to reinforce this group of ships.

Initially just six U-boats, but they're going to be reinforced as the Wolfpack and the convoy barrel their way north in this, what they hope is a running battle and nibbling away at this convoy. It's the Dan Snow's history. Don't go anywhere.

There's more to come. I'm Matt Lewis. And I'm Dr. Alan Orjanaga. And in Gone Medieval, we get into the greatest mysteries. The gobsmacking details and latest groundbreaking research. From the greatest millennium in human history. We're talking Vikings, Normans,

kings and popes, who were rarely the best of friends, murder, rebellions, and crusades. Find out who we really were by subscribing to Gone Medieval from History Hit, wherever you get your podcasts. and angus approximately how many torpedoes might each of these submarines these u-boats have on them a typical type 7 u-boat which is the main kind used by doing it to the stage of the war

had four tubes forward and stern tubes so So it could fire four torpedoes, then reload them. And that took, depending on the sea conditions and moving bags of stores and provisions blocking the torpedo room, because every centimeter is used up with whatever stores they can to keep the boat in the sea. It could take anything from 20 minutes to 40 minutes to reload the torpedoes and fire off another spread. So you're looking at six U-boats with initial torpedo capacity of probably about 50 torpedoes carried between them. So they've got plenty of firepower. Tell me, how does it go?

When they reach Cape St. Vincent, do the Germans spring their trap? Well, the convoy sails from Gibraltar just before four o'clock on the Sunday, the 14th of December, 1941. And they take time to form up in the Straits of Gibraltar. And like any convoy, they space themselves out into columns and rows, like a big rectangle of ships, four miles across. The ship's a thousand yards apart, about 400 yards in front of the one ahead of it and so on. So they have this big box. The escorts form two rings around it, and then it chugs off through the Straits of Gibraltar and into the Atlantic. Because Vice Admiral Fitzmaurice has warned that the U-boats are there off Cape St. Vincent, it's not just the Germans who have intelligence reports. The British have been using Enigma and other sources and radio direction finding to give them intelligence. So they knew the wolf packs

were there. Actually, the port admiral in Gibraltar had already sent up a group of destroyers to hunt for these U-boats. But when he got out into the Atlantic, Fitzmaurice and Walker decided to go left instead of going straight on. So essentially, they hug the Moroccan coast for the first day or two of the voyage and neatly sidestep the U-boats. So the Germans lose contact. They know they're going out, but for a crucial day, they lose contact with the convoy. And it has a day or so of sweet sailing without any trouble. The danger comes on the 17th of December, three days into the voyage, when one of those Condor reconnaissance aircraft spots them

and then Donitz knows where to send his U-boats to intercept it. And that's when the convoy battle really starts in earnest. What's Johnny Walker going to do differently in this convoy battle? How are his tactics, his practice and his teamwork really going to make themselves show? What's really different with Johnny Walker is that he has welded his own team together and they know what to do. But also he's got a number of other escorts which are just there for the voyage, but he's imbued in them the same spirit of this hunting desire. So he's basically told them what he expects of them. And it's first put to the test on the morning of the 17th of December. He has one crucial advantage, not just his own escorts and the training he's given them and his tactics,

but he also has audacity. She's a little escort carrier. The Navy called it an auxiliary carrier at the time. It later became an escort carrier, the same type of ship. Adasti was a converted cargo liner, a German cargo liner that was captured in the Caribbean, sent to Blythe, the northeast of England, and told to be converted. And as the squadron commander of the little fighters put on board her said, basically the Navy got this liner, stripped it down to a deck, stripped away her upper deck and stuck a flight deck on her. That's essentially what she was. She looked like a big raft.

No island like you'd expect with an aircraft carrier, a tiny little flight deck. And for this voyage, they only had four martlet fighters. The Americans called them wildcats and the British, of course, had to give them their own name of the martlet. So he had this one advantage, and the British, of course, had to give them their own name of the martlet. So he had this one advantage, which was very new. Audacity had sailed down to Gibraltar in a previous convoy. Her pilots meant to shoot down a condor, and that showed the way that she was useful. The other thing they had is they took off in a dawn sweep around the convoy. A couple of martlets went out and peeled off in either direction, circled around the convoy looking for U-boats. And that's exactly what happened that morning. So he gets the warning that a U-boat's on the surface 25 miles away from the convoy. The doctrine is the escort stick with the convoy and protect it.

What Walker did differently was he sent a group of escorts out hunting that U-boat, vectored in by the martlet, which was circling around. And throughout the morning and into the afternoon, they locate it and start pounding it with depth charges. And what Walker's tactic was, before you have one escort finds a U-boat, detects it using ASDIC, but it's a kind of cone ASDIC, it points downwards. So when the escort passes almost over the U-boat, which it has to do to drop its depth charges, there's a crucial window where the escort loses contact. And a wily U-boat commander can use that time to just speed off in a different direction and get

out of the danger zone. But what Walker did, he had one pinning it with ASDIC and then the other using radio. It would guide the others over the target and tell them when to drop the depth charges. So for Walker, it was all about teamwork and aggression. They would just keep pounding it until the thing was sunk. So he's using this new capability. He's got eyes in the sky and then he's actively hunting these U-boats and working as a pack. U-boats aren't the only people capable of working in a pack. His escort vessels are now doing that as well.

And so how does the battle progress? They managed to sink this U-boat away from the convoy. Are any of the other U-boats getting in close? Yeah, U-131 is sunk just in the early afternoon of the 17th of December. Another U-boat is actually sunk off Capes and Vinson, one that was lingering there, U-127, was part of the Wolfpack, but didn't actually make it to the convoy because she was jumped by destroyers running out of Gibraltar. But the convoy, thanks to these condors, they know

it's there. So Dönitz is clustering, he's sending reinforcements down to join it. But during the 17th and 18th of December, he has about four or five U-boats shadowing the convoy, waiting for the moment to attack it. What the U-boat commanders didn't really expect was audacity. The advantage given by those, as you put it, eyes in the sky, which is exactly what it is. It gave Walker the chance to locate U-boats over the horizon. And that's what they did. The convoy would chug along and the U-boats during daylight would lie off just over the horizon and shadow it. They would see the smoke of the convoy, of the ships, and they would just go on a parallel course and then move in at night. But thanks to Audacity and thanks to Walker's ability to actually take this leap of faith and take a group of his escorts and send them off, it's quite a break with tradition to send a group of warships 25, 30 miles away from the convoy to intercept a U-boat. But that's exactly what he did. The next day, the same thing happened on the

18th. Another one was spotted by one of Audacity's fighters. And again, Walker sent a group of warships in and pounded it. The U-434 sank just before 10 o'clock that morning of the 18th. So he's having quite a bit of success there with these attacks, all because of this combination of aggressive tactics and the use of air power. Well, you say aggressive tactics, Angus. Doesn't he actually smash his own ship into a U-boat at one point on the 18th? He does. That's taken aggression a bit too far in a way. But there was a major attack. As you

point out, things start to get a little hairy. And on the morning of the 19th of December, he's told by the Admiralty, they have intelligence reports that up to seven or eight U-boats are shadowing them and are planning to attack them. So he knows he's in trouble. He's developed tactics, though, to cope with this kind of thing. Normally, it's designed for if a merchant ship goes up. He has developed a thing called Operation Buttercup. It was a nickname for his wife, but he also used it as a nickname for his anti-U-boat tactic. So picture it, the early morning of December, HMS Stanley, which is one of those old ex-American

Lend-Lease destroyers, is behind the convoy. And on the morning of the 19th, it's torpedoed by U-574, a guy called Gengelbach in charge of it. And this takes everyone by surprise. At the time, on his open bridge, and remember, all the ships have open bridges. They're not nice and warm and secure like modern warships. But about a mile or so away, Walker is having his cocoa brought to him, or tea brought to him, or something. A mile to port, another escort just erupts in flame. So immediately, he figures out what's going on. The convoy is ahead of him. He's behind the convoy. He launches Operation Buttercup Astern. He has Buttercups, Port, Starboard, Forward and Astern. And what happens is, in his tactic,

a couple of the escorts at the side of the convoy double back, head south on either flank of the convoy, as it were, four or five miles apart, and fire off star shells. And they literally bathe the whole area in between in light. And the aim is U-boats attack at the surface. They want to get away on the surface. And he wants to drive that U-boat underwater. At the same time, Stork, his sloop, turns around and starts dropping depth charges, keeping about a mile away from the wreckage of Stanley, which is going down quickly because he doesn't want to hurt the men in the water. But again, he's trying to scare the U-boat into submerging, which is what Gengelbach does. I'm Matt Lewis.

And I'm Dr. Eleanor Janaga. And in Gone Medieval, we get into the greatest mysteries. The gobsmacking details and latest groundbreaking research from the greatest millennium in human history. We're talking Vikings. Normans. Kings and popes. Who were rarely the best of friends. Murder.

Rebellions. And crusades. Find out who we really were. By subscribing to Gone Medieval from History Hit. Wherever you get your podcasts. And then he can pin it on Azdic and he finds it and starts hunting it. Again, he drops big patterns of depth charges before he's just doing one or two just to help drive it under. Meanwhile, the whole area is bathed in light by Vetch and Samphire, these two corvettes running in off star shells. And the cat and mouse thing begins with Stanley and U-574.

And eventually, he depth charges it and brings it to the surface. Then, as he points out, this bizarre situation happens where the U-boat and the sloop, Walker's sloop, start circling around each other. The U-boat's got a better turning circle than the sloop. But they're going around each other, firing at each other until Walker eventually manages to ram it. Now, this has been done before in the war. It was done later, too, in the Operation Pedestal in the Mediterranean during the multi-convoys. But it's an expensive thing to do in a warship. In Walker's case, it actually wrecked his Aztec. So it put her out of commission in that

respect. But he ran the U-boat and for good measure, he depth charged it as he went over it. So that was the end of Genkelbach's U-boat. There were a number of survivors, but again, it was a third kill of the convoy. But Stanley was hit. The convoy didn't get off scot-free that night. While this was going on, another U-boat, U-108, sank the first merchant ship, the SS Rooking. It sneaked up to the convoy and torpedoed it while all this mayhem was going on further astern. But otherwise, the convoy got through the night in one piece. So one escort lost, one merchant ship lost, but three U-boats, four of the one-off Capes and Vincents.

So the tally is unbelievably good for the Allies at this point. And presumably, this is Walker and the Royal Navy sort of using a bit of Dönitz's logic, because the Germans have a finite amount of U-boats as well. So the kind of attritional rate can work the other way, can't it? Actually, by finding and destroying German U-boats, even if you occasionally have to withdraw the escorts away from the convoy, that has a particular value of itself.

It's good to, well, frankly, kill these experienced crew and officers, and it's good to sink these boats. That's exactly it. And that became the tactic later in the war. The war of attrition was turned around and it was kind of Walker who showed the way for that. The convoy continued on. The use of audacity was a breakthrough. And by this stage, even just a week into the voyage, audacity had really proved her worth. For instance, on the early morning of the

21st, he found two U-boats on the surface with a plank between them. So they were transferring men and stores from one to the other. The idea is they think one was damaged and they were patching it up. Things like that were new territory for the Allies using escort carriers. And the other advantage was the Condors, these pesky reconnaissance aircraft that could shadow a convoy for several hours until it was relieved by another aircraft right through daylight, and they could vector in U-boats to the spot. What happened was, for the first time in that convoy, one of Audacity's aircraft shot down a Condor. And that was done by Sub-Lieutenant Winkle Brown, Eric Winkle Brown, who became Britain's most famous test pilot and a real

star of the fleet air arm. These Condors are heavily armored, bristling with guns. He figured out that by playing chicken with it, flying straight towards and shooting at the cockpit, basically a head-on run at it, that was the weak point. And that's exactly what happened. The perspex of the Condor's cockpit just obliterated with 50 cal rounds and the Condor was shot down. One of the other pilots shot down another Condor that evening and other ones were driven off the following day. So the Condors were becoming wary of the potential of Audacity and Audacity was actually becoming targeted now. They were raging back to Dune, it's insane, do something about this damned escort carrier.

And they did do something about it. They did. The big climactic battle of the convoy comes on the 21st of December in the evening. Walker's come up with a plan. He'd send four escorts off in a little group to stage a mock battle, sending off star shells and dropping depth charges. That was to attract any U-boats around. And that was on the original course of the convoy.

At the same time, the convoy would do a sharp turn to port and would head off in a different direction in an attempt to fool the Germans. It didn't really work, mainly because as soon as this mock battle started, a lot of the merchant ships fired off their own flares so they could be seen for miles around. So it was kind of a big foobar by the convoy. And Walker and the convoy commander, Fritz Morris, were furious. The next day, there was very blue language being shared between the two lots. This has happened before in convoys, but there's particularly bad because this mock battle basically didn't manage anything. The new boats knew exactly where to go. At this time, Adasti had pulled herself out of the

convoy. They knew a big attack was coming. They had six or seven U-boats reported in the area. So Commander McKendrick, the skipper of Adasti, decided he was too big a target now for the safety of the convoy. He pulled off and operated on his own. He actually was senior to Walker, so Walker couldn't order him to stay put and be protected. So all he could do is recommend, and McKendrick decided that safety, for his part, would be sneaking along on his own. Unfortunately, when all this was going on, the mock battle was taking place, a U-boat, 751, U-751, spotted what it thought was a lone tanker, a straggler, and it fired off a couple of torpedoes

at it, a spread of torpedoes. It was actually a Dasty. The U-boat commander only realized this when he hit it. When the torpedo exploded, he saw it was a small carrier. Even later in the war, the Germans thought this was a full-size carrier, but a Dasty was sitting there crippled by this torpedo hit. And at the same time, the convoy itself was under attack. So all Walker could do at the time was to get the four escorts, including the sloop Deptford and three corvettes. And they were sent off like the cavalry to try to support Adasti while she was sitting there, basically a lame duck in mid-Atlantic. basically a lame duck in mid-Atlantic. But the convoy was under grave attack, U-567 commanded by the U-boat Endras, Engelbert Endras, who was the deputy of Gunther Prien when he attacked Royal Oak and Sanker just a few miles from my study window here in Scapa Flow in October 1939. But

Endras was a big figure at the time. When Durnett sent him to reinforce the convoy, he sent the signal, Endras is coming, as a morale booster for the other U-boats. But four U-boats attacked the convoy that night, including Endras' one. And Endras sank a merchant ship. He was the only one to do that that evening. The Norwegian ship, the DS Anivor, which sank in a minute. There were just four survivors of the crew of about 40. And this time, Walker made a mistake, a rare thing for him. He decided the attack came from starboard, so he ordered buttercup starboard. And his escorts went looking for the convoy there, sending off star shells in that direction. But actually, all he did was split up his escort. Fortunately, the rest of the remaining escorts managed to hold off the U-boats. And better still, that evening, one of them, Deptford, managed to sink a U-boat. It didn't know which one it was, but it turned out a few days later, it was actually Endras. He never returned home. So U-567 went down with all hands.

But meanwhile, over to one side on its own, about 10 miles away, Audacity was sitting there, crippled on the surface. And the crew report, including Winkle Brown, who was on deck, report they seen the U-boat on the surface coming back for a second attack. their torpedoes. And Big Al, the commander of the U-boat, launched a final spread, which sank Audacity. They could see the U-boat lying about half a mile away. The fluorescence from the water lapping over its bow was clearly visible. So boom, they get torpedoed and Audacity sinks with the loss of 76 of our crew. So a big blow for the convoy. That's Major Escort. So second big night battle where they lose a merchant ship, but they also lose a warship. In this case, Audacity, it was a grievous loss. But at the same time, they also sing their next U-boat. Endras goes down. So another battle, which is

mixed results. Both sides take losses. But the next day, this is the 21st of December, they start coming into range of land-based aircraft, and they know the odds are turning. Now, they get reinforcements coming in the next day or so from Western Approaches Command, extra destroyers. But this time, Walker's escorts, they're all exhausted. They're tired. They're almost out of depth charges. One of his escorts got back to Liverpool with one depth charge left out of 32. So they've been really whopping the U-boats as much as they could. The convoy really takes a bit of a pounding and the loss of a desk is a grievous thing. But over the next couple of days, aircraft start coming out, covering it from Britain, reinforcements come in, and the convoy is obviously not home and dry, but its safety is almost assured. And at that point, Vice Admiral Dunitz, in his mansion in Lorient, overlooking the sea, unbelievably decides to end the attack and recall his U-boats. They've taken far too many losses for a convoy, an unheard of number of losses.

And the loss of Endras was a real blow to Dunitz. It made a big thing of Endras in terms of publicity before. And so for the German people, that would be a huge loss for the war. So he sent some of the U-boats back to bases at Lorient, Saint-Nazaire and places like that. But others were sent out into the Atlantic against easier prey. So thanks to Walker, thanks to Adasti, HE-76, the 32 ships, made it into Liverpool on the 29th of December with only two losses. And given the losses in previous convoys, that was very impressive. But even more impressive was the tally of U-boats sunk by the escorts directly in one other. As you put it, it was turning that whole war of attrition and the tonnage war around against the U-boats. And that was the first time that had been done. So it was a real turning point in the Battle of the Atlantic.

It was a blueprint as well for victory. Johnny Walker would play his part in many more of those, but I just want to come back to your point about exhaustion. I mean, it killed him eventually, didn't it? He would have been on that open bridge for days on end. Yeah. When he got back, the Admiralty took him to a meeting in Whitehall in the Admiralty and basically took on board his tactics. And that became, as you say, the blueprint for the Royal Navy's anti-submarine warfare plan for future convoys. They were getting more escorts now. They could do this. They could actually form hunting groups accompanying convoys, whose whole job was to go out and do Walker's thing. And Walker was given command of one of these. And he spent the next few years doing exactly that, hunting U-boats. He became Britain's big U-boat hunter until, as you point out, essentially exhaustion got him in the end. He wasn't a young man. He was in his 40s, which is old for somebody sitting on a bridge of one of these escorts. And medical conditions got the

worst of him. But essentially, he wore himself out. But it was to the detriment of the U-boats. He kept proving the worth of his tactics right to the end. And audacity too. Although she was sacrificed, the Admiralty realized that the escort carrier was the way forward. America had already produced the USS Long Beach, which was their prototype, very similar ship, but a bit better. It actually had an island and could carry more aircraft. And then they start mass producing it in shipyards in Canada and the United States. So the escort carrier was going to be a thing now. It helped bridge that gap between land-based aircraft in mid-Atlantic and provide convoys and escorts with the tool they needed

to actually detect U-boats and sink them. Angus, thanks for coming back on the podcast. That was another tour de force. What's the new book called? The book is called The Convoy, HG-76, Taking the Fight to Hitler's U-boats. And it's published this October by Osprey and Bloomsbury. Thank you, Angus. Thanks for coming on the podcast.

My pleasure. you