Cold Open

It’s just after 3 AM, on August 19th, 1941, in the North Atlantic Ocean.

In the control room of German submarine U-201, Commander Adalbert Schnee winces as an officer knocks over an empty mug. Schnee shoots the man a withering glare, but says nothing. His rebuke can wait for later—because right now, even the smallest sound could give away his U-boat’s position.

For the last 36 hours, U-201 has been shadowing an Allied convoy headed for the port of Gibraltar. Schnee’s vessel is just one of a “wolf pack” of German submarines tasked with stalking these merchant ships—and, when the time is right, they will strike the fatal blow.

Commander Schnee holds his breath as U-201 glides closer to his chosen target. Moving just below the surface of the water, the submarine inches into firing position. And then, Schnee gives the order.

A torpedo leaves the tube. Schnee listens, senses' sharped… until the noise of an explosion echoes through the water. U-201 is so close that the submarine even rocks from the impact. But Commander Schnee doesn’t linger to see the damage he’s caused. He knows that the destroyers escorting the convoy will be hunting for them within seconds. So, he orders U-201 to dive.

Over the next few minutes, the silent submarine disappears into the depths of the black Atlantic. The only trace it leaves behind is a scattered convoy and a merchant ship in flames.

Soon after U-201 slips away, the stricken Allied merchant ship sinks. Among those on board who'll lose their lives are 22 members of the British Women’s Royal Naval Service, also known as Wrens. Across Britain, thousands of young women like them have volunteered to help the war effort. But one very special group of Wrens will soon get a chance to avenge their dead comrades and change the course of the war in the Atlantic when “Operation Raspberry” begins on January 1st, 1942.

Introduction

From Noiser and Airship, I’m Lindsay Graham, and this is History Daily.

History is made every day. On this podcast—every day—we tell the true stories of the people and events that shaped our world.

Today is January 1st, 1942: Operation Raspberry Takes on the U-Boats.

Act One: Cripples, Women, and Broken Ships

It’s January 1st, 1942, at the Admiralty Buildings in London, England, 16 months after U-201’s attack in the North Atlantic.

42-year-old Gilbert Roberts sits alone in a bustling mess hall, watching the uniformed officers and sailors of the Royal Navy hurry past. He can’t help but feel a pang of envy. Five years ago, Roberts was one of them—the commander of a destroyer. But then, he contracted tuberculosis and was discharged from the service for medical reasons.

And when World War II broke out in September 1939, Roberts was still on the sidelines, a retired officer deemed unfit to serve. He eventually found a role training sailors in counter-invasion tactics on the south coast and threw himself into his work. But a few days ago, he received an unexpected invitation asking him to report to the Admiralty.

So not knowing what to expect, Roberts is a little surprised when a man slides into the chair opposite him and sets down two steaming cups of tea. Admiral Cecil Usborne once held a senior role in British naval intelligence. Now, he’s an aide to Prime Minister Winston Churchill and a vital part of the British war effort.

He wastes no time on small talk. Over the next few minutes, Usborne explains why he’s asked Roberts here today. He’s heard great things about Roberts’ efforts on the south coast—in particular, the inventive way that he uses games to teach his men. Roberts asks his sailors to pretend to be German commanders and has them launch mock attacks in tabletop battles. Other sailors playing as the British must work out how to counter them. It’s an innovative training technique that forces the men to think more strategically.

But now, the threat of imminent invasion by the Germans has passed, and Admiral Usborne thinks that Roberts’ talents would be better used elsewhere.

Since the start of the war, German submarines, or U-boats, have prowled the Atlantic Ocean. They don’t just target the Royal Navy—they also attack merchant ships carrying precious food, oil, and other supplies from North America. So far, more than 1,500 British and Allied ships have now been sunk by the U-boats, but the Navy is no closer to finding an effective way of fighting back.

As their tea cools, Admiral Usborne leans forward and makes the stakes brutally clear. Without raw material brought in by sea, Britain cannot keep its factories working at full capacity. And without grain imports, the country is edging ever closer to starvation. If Britain is to remain in the war, it needs to find a way to blunt the U-boat threat.

Hearing this, Roberts wonders if he’s about to be restored to command of a destroyer. But Usborne has something else in mind. He wants Roberts to use his mastery of war-games to turn the tide in the Battle of the Atlantic. Roberts will be tasked with running simulations that analyze U-boat tactics and identify the best way to defeat them.

Realizing the opportunity, Roberts doesn’t need to be asked twice. Admiral Usborne offers his hand across the table, and Roberts quickly grasps it.

And just like that, Roberts is back in the Royal Navy.

That same night, the newly reappointed Captain Roberts boards an overnight train from London to the port of Liverpool. Thanks to speed restrictions on the line, blackouts, and the constant threat of German air raids, the 200-mile journey north is a slow one. And when Roberts arrives the next morning, he is given a tour of his new workplace: Western Approaches Command, the headquarters of all Royal Navy operations in the Atlantic.

In one vast room, sailors plot the positions of every Allied ship on a giant map of the Atlantic Ocean. Several markers are stamped with red crosses — ships that are already lost. Small tokens indicate where U-boats might be lurking.

But the bustling map room is not where Roberts will be based. Instead, he’s led to the derelict top floor of the building. Here, in a dusty, forgotten room, Roberts is told to establish his new unit. Roberts asks how many people he’ll have. But his guide just shrugs—as far as he knows, right now, Roberts is on his own.

But Roberts will need a team. And when he finds it, it will be just as unusual as the dusty room he calls home. In this unlikely-looking space with his unlikely team, Captain Gilbert Roberts will soon be waging epic fake battles. But the hope is that they will help the Allies win a very real war.

Act Two: Raspberry

It’s April 25th, 1942, in Liverpool, England, four months after Captain Gilbert Roberts was appointed to a new post.

20-year-old Janet Okell peers through a canvas sheet hanging from the ceiling, straining for a good view of the chalk and string on the floor before her. The crude markings form a map of the Atlantic Ocean, and the canvas is supposed to mimic the fog of war.

Janet is playing the role of the British in a naval war game. And it’s her job to get the counters representing Allied ships from one side of the floor to the other. But behind another canvas sheet on the opposite side of the room, someone else is playing the role of the Germans, and their job is to stop her.

Janet is part of a small team who’s working with Captain Roberts at Western Approaches Command. When he first arrived in Liverpool, Roberts struggled to get his new tactical unit taken seriously. Despite Roberts’ support among some of the top brass in London, many officers at Western Approaches looked down on his unusual approach—to them, Roberts was playing games, while they were dealing with real-life-or-death battles on the high seas.

So, when it came time for Roberts to be assigned a team, no one was willing to give up their men. Instead, the only staff made available were from the Women’s Royal Naval Service. But if Roberts was disappointed with his new recruits, he soon changed his mind. He saw that these young Wrens had sharp intellects, discipline, and a desire to learn.

So with the Wrens at his side, Roberts set out to understand the behavior of U-boat captains by recreating their decisions on a game board. His goal was to learn how the enemy attacked, so that he could identify the most effective countermeasures. And over the past few months, Roberts and the Wrens have worked around the clock. After completing hundreds of simulations, they have made a key tactical breakthrough—and today, it’s time to unveil their findings.

Janet scribbles her next move on a slip of paper and passes it to another Wren. She steps onto the chalked floor to move the Allied counters. And when she does, Janet peers through the canvas again, this time toward a man watching them all from a raised platform. Admiral Sir Percy Noble is the commander-in-chief of Western Approaches Command and the most senior British officer overseeing the Battle of the Atlantic. He’s come to see what Roberts and the Wrens have discovered.

And he watches as the Wren at the map announces that the German U-boats have launched their attack on Janet’s ships. But Janet doesn’t flinch. Over the past few weeks, she’s run this exact scenario dozens of times. Early in their work, she and the other Wrens assumed that the U-boats fired from long range to avoid detection. But when they replayed real-world engagements based on survivor testimony, they began to suspect something else. They came to believe the U-boats were actually firing at near point-blank range to ensure they hit their targets, before immediately diving to escape detection.

Once the Wrens realized this, they could come up with an effective countermeasure. They worked out that if Allied destroyers dropped depth charges around a merchant ship as soon as it was attacked, they had a far better chance of hitting the fleeing submarines. Of course, the Wrens playing as U-boat commanders then changed their tactics too. They began launching their torpedoes from a greater distance. They were far less effective from there and missed their targets more often than they hit.

So behind her curtain, Janet writes her next move, passes it forward—and the Wren at the map announces that she’s scored a direct hit on a German submarine. The normal quiet atmosphere of the simulation room is broken by Admiral Noble applauding. It might only be a mock battle, but Noble doesn’t get many chances to celebrate the sinking of a U-boat.

So when the demonstration is over, Noble congratulates Commander Roberts, Janet, and all the other Wrens. He then asks what they’ve named their new tactical maneuver. Janet steps forward, her cheeks reddening, and admits that they’ve called it Operation Raspberry, their way of blowing a raspberry at Adolf Hitler and his U-boats.

Admiral Noble laughs because he likes that. Impressed with what he’s seen, he immediately sends out new orders. It’s time for the tactic to be tested in the real world. And only then will Captain Gilbert Roberts and the Wrens discover whether their long hours hunched over a chalk-covered floor will really make a difference in the Battle of the Atlantic.  

Act Three: Wrens Vs Wolves

It’s the early hours of May 6th, 1943, in the North Atlantic off Newfoundland, a year after Operation Raspberry came up with a new way of fighting U-boats.

On board the frigate HMS Tay, 36-year-old Lieutenant Commander Robert Sherwood swings his binoculars around as a torpedo detonates close by. A plume of water shoots up into the air a few hundred yards away. The explosion was close to a merchant ship—but thankfully, it missed its target.

HMS Tay is escorting a convoy of over 40 merchant ships. A wolf pack of German U-boats has been tracking them for days, and just last night, they sank ten of the Allied ships in a devastating attack. Now that darkness has fallen again, the submarines are back for more.

But this time, Commander Sherwood knows exactly how to respond. Following the protocol of Operation Raspberry, he steers directly toward the merchant ship the torpedo was meant to hit. Then, Sherwood orders his men to fire star shells.

These special flares light up the night, and Commander Sherwood’s breath catches. In the sudden brightness, he can see the silhouette of not just one U-boat lurking below the surface—but seven. Sensing a rare opportunity to destroy an entire wolf pack, Sherwood calls out orders to drop depth charges.

As the explosions shake the water beneath them, the German subs scatter. But the battle is not over yet. All through the night, the U-boats come back again and again, trying to slip in close for a point-blank shot—exactly as Captain Gilbert Roberts and his Wrens predicted they would. But each time, the convoy’s escorts counter and push the German submarines back.

By dawn, the British sailors are tired but exhilarated. Not a single Allied ship has been hit, but the oil slicks floating on the water suggest it was the Germans that have taken damage instead.

Later that day, the merchant ships break off and head for their final destinations in North America. Their safe arrival is a triumph for Commander Sherwood. But the real geniuses behind this victory are hundreds of miles away on land, in a chalk-covered office in Liverpool. The work of Captain Roberts and Wrens like Janet Okell has saved hundreds of lives in this one convoy alone.

And by the end of 1943, more than 5,000 officers will be trained in new tactics that will help turn the tide in the Battle of the Atlantic. The once-formidable U-boat threat will collapse. And the all-important supplies of personnel, machinery, ammunition, and food will flow across the Atlantic almost unimpeded.

After the war, Gilbert Roberts will be presented with the Order of the British Empire. The Wrens who worked beside him will receive no official recognition—no wartime honors, no medals. But without their tactical breakthrough, Britain might have starved and been forced to surrender to Nazi Germany. Instead, victory in the Battle of the Atlantic began with Operation Raspberry on January 1st, 1942.

Outro

Next on History Daily. January 2nd, 1492. Spanish monarchs Ferdinand and Isabella capture Granada, the last Muslim stronghold on the Iberian Peninsula.

From Noiser and Airship, this is History Daily, hosted, edited, and executive produced by me, Lindsay Graham.

Audio editing by Muhammad Shahzaib.

Sound design by Mollie Baack.

Music by Thrumm.

This episode is written and researched by Owen Paul Nicholls.

Edited by Scott Reeves.

Managing producer Emily Burke.

Executive Producers are William Simpson for Airship and Pascal Hughes for Noiser.