Original subtitles

Bull's eye.

Action! Action!

Die! Die!

Why the hell have you died?

Britain may have dealt with Dönitz's aces.

No way back to Germany this time.

But his U -boats keep coming.

Fire!

New orders for Group Paukenschlag.

Attack at will in all coastal areas.

They think ships faster than Britain can build them.

If we keep losing ships at this rate, the country will be down to just a few

weeks of supplies.

People will be starving to death.

Happy hunting.

The Royal Navy turned to retired wargamer Commander Gilbert Roberts and

a group of young women.

Sir? Ladies, if we lose the Battle of the Atlantic, we lose the war.

Our job is to find a way to sink the U -boats.

That is what we will do here.

They're the bodies that... By recreating battles and playing through scenarios

in a war game.

Is that Donitz's master tactic?

We need to work out how to destroy them.

Gilbert Roberts reports to Western Approaches Command, the Royal Navy's

of operations for North Atlantic convoys in Liverpool, England.

Gilbert Roberts could be doing so much more at this point.

Here's a man who's had two years' training in war games.

War gaming allows you to understand how tactics work and it allows you to

explore new tactics.

Churchill couldn't be less pleased with how the battle of the Atlantic is

turning out. The fact that they're losing hundreds of thousands of tons of

merchant shipping to U -boats.

Enter. What Churchill has to do is not just stay in the war, but win it. You

only win it if you're going to win the battle of the Atlantic.

Sir, Commander Robert.

Thank you. That will be all.

Commander Roberts retired.

I thought London was sending me a captain.

A no -sir sector commander.

Portsmouth Naval Anti -Invasion Battalion.

The Home Guard.

Instructions from the Admiralty say that I'm to give you the top floor of the

Exchange Building.

For? A school, sir. A school.

A tactical school.

The Prime Minister has asked me personally to analyse U -boat attacks,

their tactics, and develop counter -tactics to think them.

These would then be taught to escort commanders at the school.

We already have a counter -tactic, Robert.

Buttercup.

Developed by our own Commander Walker, a man who has actually sunk U -boats.

Have you?

No, sir.

And I'd very much like to begin with Buttercup.

By analysing Commander Walker's actions, I can then play through other scenarios

in a war game and identify any tactical weakness that we all gain.

Tactical weakness?

I'm sorry, but what does affect a commander of the Home Guard know of

I spent two years at the Portsmouth Tactical School, sir.

War gaming.

Back before retirement.

School to play games.

And I'll need men to staff the unit, too. Men with good analytical minds.

Good with records.

But mostly good at playing the game.

Commander, I'm in the middle of fighting a war.

All my best men are at sea.

You might be able to scrape together a couple who are unfit for active service,

but if you need more to play your game, you should speak to London.

Thank you, sir.

Owen Roberts, this is school.

Perhaps you can run occasional courses for half a dozen reserve officers, but

don't bother me with it. I'm a busy man.

Dismissed. Percy Noble doesn't seem to be taking on board the importance of

finding new tactical ways forward.

Donuts is a tactical master.

This is a time where it's more crucial than ever that he listens to Roberts.

Sir.

Because he is paramount.

Yeah, quite right.

And for the Royal Navy, help arises from an American tragedy.

After the attack on Pearl Harbor, the USA declares war on Japan.

Four days later, Germany sides with their Japanese ally and declares war on

USA.

The Americans have already been unofficially supporting Britain through

Now they mobilize at full strength.

The idea was to get to Germany, to defeat it first, but of course doing

meant getting supplies and equipment and now manpower as well to the British

Isles in preparation for an eventual invasion of Nazi Germany.

But the American...

Involvement created new opportunities for the German U -boats to attack

shipping. Donitz saw this immediately.

The United States Navy should have been prepared for a submarine campaign. But

the problem they have in early 1942 is they don't have enough destroyers trying

to protect merchant shipping. Most of them have gone to the Pacific to fight

Japanese.

This lack of protection presents Dönitz with a golden opportunity.

He measures his U -boat captain's success by the number of ships they send

the bottom.

Admiral Stubbs, officer.

Orders for Group Parkenschlag.

Proceed to Naval Square CA -28.

New York.

Yes, Herr Admiral.

He knew that the shipping would concentrate off New York, off Cape

Cape Cod.

American involvement in the war gave the U -boats a lot of new targets off the

American coast.

Hey, Admiral.

Have the Americans learned nothing from the British?

Very heavy traffic.

Mainly north -south.

Very many tankers.

Occasional neutrals.

No surveillance.

They're not even trying to protect their ships.

The United States Navy don't have the escort vessels they need to establish a

system of convoy, so they decide not to do that.

There's a marvelous directive that comes from the Office of War Information.

Quite simply, the Germans can sink as many ships as they like. It really

matter, because American industry is just going to bury them in new shipping.

All the more prey for the wolves to feed on.

New orders for Group Paukenschlag.

Attack at will in all coastal areas.

January of 1942, they sank 41 ships, 250 ,000 tons in just two weeks.

And a lot of those sinkings were just off the coast of the United States,

literally within sight of American home territories.

German success is so profound that it becomes known as the second happy time

the U -boat fleet.

With the Americans being destroyed in such numbers, it's more and more

that the convoys that do survive are protected, that the Royal Navy gets

ships across.

The scale of the task is enormous.

Every available man is put to work, but there aren't enough.

Without women, we realise we can't win the war.

Now, that is a whole new ballgame for men to get their heads around and for

young women to engage with.

The Royal Navy are forced to rely more and more on Vera Lawton Matthews' wrens.

I do appreciate having your wrens here.

Certainly brighten the place up.

They can do more than that.

Much more.

To begin with, the Wren have just nine roles, and they are fairly humdrum. If

you're lucky, you're a typist, all right, or a driver. Those minimal

opportunities expand to over 125 roles.

One of those are as codebreakers of the highly secretive Bletchley Park,

deciphering radio messages between Durnitz and his U -boats, providing

intelligence on when to expect U -boat attacks.

But despite the best efforts of the men and women of the Royal Navy, they still

haven't deciphered the enemy's tactics.

Even though Roberts initially gets a very frothy reception, he is delighted

be back. He'd been cast out of the Navy due to having TB just four years

earlier.

This is a man who had spent quite a lot of time in the interwar period thinking

about these problems.

He can use his skills, he can contribute to naval success, and if possible, he

can contribute to victory.

As if to undermine Roberts's position even further, he isn't put in the main

headquarters. His offices are in a different building, which hasn't even

finished. It's still under construction and it's been bombed.

What's this?

A gift from Herman Goering. Damaged from an incendiary bomb.

He needs to go.

Arrange for it to be cleared.

Yes, sir.

I'll need battle reports.

Anything detailing a successful U -boat kill.

Including convoy HG -76.

Commander Walkers.

Buttercup, try up.

Yes, sir.

He needs as much information as he can get about what's really facing

when they're out in combat to figure out what the U -boats are doing and how to

defeat them.

I also need supplies to build the game board.

Canvas sheets, roll of linoleum. Chalk, string, paint.

And model ships, yes?

Yes, sir. Very good.

These requests raise eyebrows at Western approaches.

I mean, here is this newcomer who wants to play games while battle rages in the

Atlantic.

Anyway, sir, all this tactics and wargaming might be for naught.

We already captured that also Kretschmer, and they already started

him. Surely he'll spill the beans and give up all of Donnett's secret tactics.

Surely.

From 1939 to 1941, Kretschmer unleashed a reign of terror against

Allied shipping.

A hunter's moon.

Just as I like it.

Prepare for attack.

Yes, sir.

Fire bowed, torpedo.

Tringing 47 ships across the North Atlantic.

Over 273 ,000 tons.

More than any other U -boat ace.

That's as good as it gets.

The human toll is 830 lives.

For his service to the Third Reich, Hitler awarded him the Knight's Cross of

Iron Cross with oak leaves and swords.

Thank you, sir.

At the time, Nazi Germany's highest naval award.

Action! Action!

Die! Die!

Why the hell have we dived?

Are you sure we couldn't have gotten away on the surface?

But in March 1941, his luck ran out.

Sir, we've lost all thrust in the propellers.

Blow the ballast tanks. Everything we've got. We have to lose depth.

Prepare scuffling charges and destroy all documents and ciphers.

No way back to Germany this time.

Otto Kretschmer's this extraordinary U -boat ace.

He's caught alive. That is such a win for the Allies.

The MI9 have got hold of him.

MI9 is a unit established to interrogate prisoners of war. It's like, if you

like, a latter -day Guantanamo Bay.

Here's your chance, boys.

Drill into him, download his microchip of knowledge, and you are going to turn

the tide of this war.

No. It's English.

Would you rather we spoke German?

No. English is good.

I might as well get you into it now.

Quite an impressive tonnage, Charlie, Commander Krebschmer.

You're very popular back home.

The tonnage king, as an apple gravels call you.

It's just propaganda.

I'm a good copy for the Nazi papers.

My picture gets more women waving flags, more men signing up to the U -boat

corps.

What for?

To sink more ships?

For Hitler?

Sorry if I don't seem too enthusiastic.

I grew weary of this war long ago.

You won't miss sinking ships?

I have sunk enough ships.

The thrill of the hunt left me long ago, too.

And how do you hunt?

You've sunk more ships than anyone.

How do you do it?

What are your tactics?

A U -boat captain, I mean a real captain, has to be able to take

whatever the passing moment offers.

You never know when you'll stumble upon a convoy.

A real captain is born with the intuition to know when to attack and how

press home your advantage.

Smashing.

Do they get the key to Otto Kretschmer's knowledge? Do they find a way in? Do

they hellas like?

This guy ain't the top U -boat captain for no good reason.

Kretschmer reveals very little to his captors.

Cernet says U -boat tactics remain a mystery.

That Western approaches command, Roberts tries to decipher them.

Sir, it's the report you requested.

Ah.

Convoy HT -76.

Commander Walker's famous buttercup tactic.

Thank you, sir.

The report of proceedings was a standard report that was written by anybody in

the Navy who had encountered the enemy. It explains what the enemy has done, but

it also explains what the commander from the Allied side has done.

Buttercup has turned.

HG -76 is important because Walker had some success during it. He wants to

understand why Walker was successful.

Sir. What has he thought up? Why did he behave the way he did? But if you're

looking at a report, any kind of report, they're very, very dry. They don't

really tell you anything about the human side of decisions that are being made.

Enter.

Sir, Commander Roberts.

What is it, Robert?

Sir, I'd like permission to speak with Commander Walker about convoy HT76.

Don't you have his report of proceedings?

Yes, sir, I do.

And you've read it? Yes, sir.

But to truly understand how Buttercup works, I need to speak with the

What assumptions did he make?

Why deploy his escorts where he did?

Robert, Buttercup works. It's a sound tactic.

which is why I ordered for it to be put into group operational instructions.

I'm aware, sir.

And now our escorts are being fitted with a new piece of technology.

Ship -mounted radar.

We'll be able to spot U -boats on the surface miles away.

That would be a great help, sir, undoubtedly.

But to complete my work, I will still need to speak with Commander Walker.

Very well.

When Walker gets back from sea, if he can spare the time, you may.

Thank you, sir.

Now, if you don't mind...

And Noble has

another reason to be confident.

The work of the Wrens is turning Western Approaches Command into an intelligence

hub.

Up and down the country, Wrens working in radio listening sites, known as Y

stations, are tracking U -boat positions.

My first station was on the Yorkshire coast, not very far from Scarborough,

where there was a very big listening centre.

By comparing the bearing of the U -boat's radio signal with another Y

the U -boat's position can be triangulated.

U -boats, of course, very seldom spoke, but now and then one would come up and

would do a signal to its base or to other U -boats.

When they did, it was a very, very tense atmosphere because they were such a

menace to our convoys and ships.

I worked out when the U -boat came up, while they got the signal from the U

-boat down, and particularly the position of the U -boat, because they

then report this back to Admiralty and they might be able to take action.

Very good.

That intelligence arrived pretty pronto via radio to weapon approaches, telling

you the real -time position of U -boat flotillas. So you plot them, you mark

them on your giant map on the wall.

And Western approaches are also benefiting from long -range aerial photo

reconnaissance.

A lot of the analysis of these photographs was done by women. They

see, for example, the U -boat pens along the French coast.

By looking at these sorts of images, you had more of an idea of when they were

going to leave the pens, when did they get back, how long were they out at sea,

and what was their direction.

It means Western approaches are much more aware of when to expect attacks.

Excellent, thank you. That's good work.

But they still can't work out how the U -boats are attacking the convoys.

Sir, this is the room.

The candidate will be with you shortly.

Thank you.

Before he can begin his work, Roberts clearly... Needs a team.

He needs people who are, quote -unquote, whip -sharp.

He needs the finest brains, boys who are going to knock the tactics back at the

enemy.

Please, take a seat.

Lieutenant Commander Cousins, DSP, sir.

DSP.

Distinguished Service Cross awarded for gallantry against the enemy.

I see.

What experience do you have of tactics?

Tactics? We smash the U -boats with depth charges.

That's all we need. We hound them out of the Atlantic.

I see.

Thank you.

Lieutenant Commander Higham, sir.

Your experience of tactics?

Sir, I've served on both submarines and ships.

And tactics?

My ship sunk.

I had to be hauled out of the water on a rope.

Donuts is a genius. He needs men who are able to think mathematically,

tactically, very clear -headed, clear -minded.

These are clearly not the sort of men that he's going to need to decipher

Donuts' tactics.

Commander Roberts, Vera Lawton Matthews, Director of the Women's Royal Naval

Service. The Reds.

You're in need of staff.

I can meet all your requirements.

I've been recruiting the people you need for three years.

Wrens. I need naval officers.

And how's that working for you?

Hmm?

Wren Drake, please enter.

Please take a seat.

Elizabeth Drake.

The daughter of an insurance factory.

Yes?

Yes, ma 'am.

Measuring risk. Must run in your family. Yes?

Yes, ma 'am.

Thank you, Drake. That'll be all.

Yes, ma 'am.

Sounds essential for your tactical game, Commander.

Next! Ren Nancy Wales, sir.

Ren Wales, what experience do you have of tactics?

Well, sir...

I captained the Yorkshire hockey team for years.

An expert in team tactics.

Thank you, Wales.

Janet Oakle.

I hear you're a formidable bridge player.

Well, yes, ma 'am. And what makes for a formidable bridge player?

Well, reading your opponents is important, ma 'am.

Reading opponents and scenarios strategically.

Mum, what is this all about?

Thank you, uncle.

That'll be all.

And finally, a real gem.

Wren Laidlaw, please enter.

Good afternoon, ma 'am.

Sir?

Wren Jean Laidlaw.

Candidate.

Yes, sir.

I haven't met a woman accounted.

I'm one of the first to qualify in the United Kingdom, sir.

I see.

Keen mind for numbers, I suppose.

Yes, sir, very keen.

Just what your game needs to calculate those moves.

I suppose.

Indeed.

Thank you, Laidlaw. That'll be all.

Yes, ma 'am.

Sir.

Right. All of them, Commander.

And they all bring a special set of skills to the table.

Exactly what the game needs.

In the early war period, almost every nation does not consider women for these

sort of roles.

The Wrens were a risk.

The task these young women are set is one of the most important in the war, if

the Battle of the Atlantic is lost.

Britain has lost.

And if Britain has lost, the Western Allies will probably lose the war.

In Liverpool, Gilbert Roberts and the Wrens begin the next phase of their

mission.

What knot is that?

It's a bowline, sir.

Where did you learn it?

The Sea Rangers.

The simplest and most resilient.

Very good.

Men, rig the canvas sheets around the frames like these.

Yes, sir.

Sir, your linoleum, string, paint chalk and model wooden chips.

Excellent.

Any news on the great Otto Kretschmer's interrogation?

Did he spill their U -boat secrets?

Of course he didn't. That would be far too easy.

It's up to us to decode them.

And the first step for that is to build the board for the war game.

The board, sir?

The board.

The board!

Sir, are you all right?

This is the thing which is going to win the Battle of the Atlantic.

I mean, the idea is preposterous.

Oh, and, sir, Commander Walker's just returned from sea. He's waiting in your

office. Well, why didn't you say?

Not a cup.

Renée Law. Yes, sir.

Wait ten minutes and join me with Commander Walker.

Yes, sir.

Roberts wants to understand how Buttercup works.

Come on, Walker.

The chance to sit down with Walker and actually try and get inside his mind.

This is a crucial moment.

What's this about, Roberts?

You want a debriefing on Buttercup to help play a game. A war game.

To play through scenarios, decipher Janet's tactics and learn how to think

you bet.

Something I've actually...

Done using buttercup. Which is why I wanted to speak with you.

Convoy HG -76.

32 merchant ships sailing homeward from Gibraltar.

19th of December, HMS Stanley torpedoed a new order buttercup.

What happens then?

Buttercup astern!

I've drilled all my escort commanders to go to battle station on the order

Buttercup. They turn away from the... Ah, Laidlaw.

Please, take a seat.

Commander Walker, this is Ren Laidlaw, member of my staff.

Laidlaw is an accountant by trade.

I've never met a woman accountant.

Adler is one of the first in the country to qualify.

So now you have.

The Stanley was hit.

We can't be sure exactly where the e -boat fired from, but they fired from

outside the convoy in.

The ship is hit.

They escaped by motoring along the surface.

On the order Buttercup, all escort ships turn outward, away from the convoy,

full speed.

chased down the fleeing sun.

Sir, how can you see the U -boats?

The attack was at night, wasn't it?

We fire starshells.

Flares of light up the sea.

We search for 20 minutes. If we spot a U -boat, we destroy them.

Find that damned hut and sink it.

Buttercup! Stop it!

Come into our little trap.

With that, you're out.

But the cup has prevailed.

There is but a gun.

And it works?

My dear, we only lost two convoy ships.

I personally thank two U -boats, and three more were hit by other forces

my command.

Sir, HG -76 had 16 escort ships protecting

32 merchant vessels.

Is that a heavy escort?

Well, no.

More than most North Atlantic convoys, but sailing out of Gibraltar, if you

don't go in heavy, then you're asking for trouble.

And how many escort ships were lost?

Two escorts.

Including the aircraft carrier HMS Audacity.

But a cup works.

We thank...

Five euros.

Admiral Noble even asked me to write it up for the escort group operational

instructions.

Yes.

So I understand.

Thank you.

Everything they tried previously just failed. And so this was really the first

glimmer of success. I mean, it was a success.

Walker manages to sink two U -boats himself and three others were sunk in

whole operation.

But it was very, very costly.

Everything's in place. Roberts has got his gang. He's got his bits.

in order to make his game work. He's got detailed battle plans so he can work

out what the U -boats have been doing and to help him, he's got his team of

brilliant minds, these young, dependable women from all sorts of backgrounds.

Vera Lawton Matthews must be incredibly proud.

She's handpicked these young women herself, and these women are not being

to do rather menial tasks of answering phones or driving cars.

This was taking the fight to the enemy and spearheading a mission to save lives

at sea.

This was using grey matter, women's grey matter.

Lorenz, let's make a start.

Welcome to the Western Approaches Tactical Unit.

Watson, for short.

Thank you very much.

Janitor Kell.

Sir, I'm so sorry I'm late. I took a wrong turn and then another and another

I couldn't find my way back. It's all right.

I'm so sorry, sir.

And I don't have a uniform yet.

That's fine. I'm glad you could join us.

The uniforms are here.

Please, collect yours.

This is Chief Yeoman Rayner. He worked with me at Portsmouth.

He knows the game inside out.

Sir, this isn't a Ren's uniform.

Well, you'll be working a lot on the floor.

Sir?

Measuring on your hands and knees and so on.

Sir, for this work, the standard skirt isn't exactly appropriate.

We're wearing the trousers now.

Indeed.

Ladies, if we lose the Battle of the Atlantic, we lose the war.

Our job is to find a way to think the U -boat.

But before we can do this, we need to decipher Dönitz's tactics.

That is what we will do here.

By playing through scenarios and recreating battles in a war game.

This is our board.

A block for the convoy.

Model 6 for the escorts.

The players are divided into U -boat captains and escort commanders.

Now, the escort commanders stand behind these screens and view the board through

these lenses.

Ren Drake, would you... How

much of the board can you see?

No, I can't see anything.

Ah, yes.

Bit of a problem.

How about now? What can you see?

Not much. Just a few models.

Just like at sea?

Exactly. It mimics limited visibility.

Just like a convoy, stretched for miles across the ocean.

And the U -boat captain, Commander Roberts?

The U -boat captain sits at the high table.

There isn't a model for the U -boat.

No. Yes, but can't see the U -boat.

Just I could see.

So how do we plot their position, sir?

Brown chalk.

Drake, can you see the U -boat track?

Not a thing, sir.

Brown on brown.

Thank you, Drake.

An adjudicator hands action events to the players written on these chips.

You bet contacts.

Aircraft sightings. Azdic pings. Chips torpedoed.

The players are then given two minutes to make their move.

They write down their instructions on these movement chips.

Core. Speed.

Azdic sweep.

Depth charges dropped.

Then they hand them back in silence so the opposition doesn't know their

intention.

And the plotters move the models.

The aim of the game is to sink the U -bats.

And the battle report we'll start with is convoy HG -76.

Buttercup.

Despite the Royal Navy's confidence that ship -mounted radar and better

intelligence will turn the tide against the U -boats, they're still sinking

ships faster than Britain can build them.

More and more U -boats keep coming.

Donuts developed the idea that 100 U -boats on active patrol in the North

Atlantic could all but shut down transatlantic shipping.

In April 1941, Dönitz had only 28 U -boats hunting at any one time.

By the beginning of 1942, that number has exploded.

How many boats do we have at sea?

88, Herr Admiral.

88.

That's close to the hundred we need to shut down the Atlantic.

What is the monthly tally from group Parkenschlag?

Parkenschlag?

A five U -boat wolf pack.

23 merchant ships sunk for 150 ,000 tons in the last month.

And they ran out of torpedoes.

But they are just five U -boats.

This is a feeding frenzy.

They are gorging themselves off the coast of America.

Fire!

The German U -boat crews are having a field day off the American east coast.

There were so many available targets that U -boat skippers could pick out the

ones that they thought would be most useful.

It led to a kind of specialization on hunting tankers, the

most valuable prices, because fuel meant war.

Britain's war machine runs on oil and very little oil is making it across the

Atlantic. Without fuel, Britain dies.

The war effort stops.

This is a very productive hunting ground.

Let's go for the jugular.

With everything in place, Roberts and his team begin.

And the first thing that they're going to do is look at Buttercup and the HG

convoy engagement.

The first time that they actually set up for the war games, they don't play a

game itself.

This exercise is really for Roberts to get all of the ducks in a row, all the

pieces on the board, to figure out what actually happened.

every single thing they know, step by step.

Where did the convoy go?

Where were the escorts? Where were the U -boats sunk?

It provides Roberts and his team with a bird's -eye view, and that is going to

give them a real advantage in understanding what went right on the

Royal Navy, but also what the German U -boats themselves are most likely doing.

Excellent.

Let's begin.

Convoy HG76.

32 merchant ships with an escort screen of 16 ships.

The escorts form a protective perimeter.

Merchant ship is hit. What position?

The merchant ship, sir.

Not the escort HMS Stanley.

No, the merchant ships are on lifeblood.

I want to see how they're targeted.

The SS Anivore. Convoy position 53.

Fifth column, third ship.

Now what?

Commander Walker orders Buttercup.

The escort turn outwards at full speed and fire star cells to illuminate the

sky.

They speed away from the convoy to try to spot the U -boat.

Walker manages to sink a U -boat earlier at the rear of the convoy. A stern of

the convoy.

A stern.

Good.

At least one U -boat down.

Proof of the attack from outside the convoy, like Commander Walker said.

Is something wrong?

The merchant ship has hit in the centre.

Can they even hit?

What's the range of a torpedo?

Leave the board as is.

I need to make a phone call.

Operator. Flag office, submarines, London.

Connecting you now.

Robert has an old friend who's based at submarine command.

So he puts in a call to his surprise.

It's answered by the commander submarines for the Royal Navy.

That's Sir Max Horton.

Admiral Horton.

Apologies, sir. I was hoping to speak with your chief of staff.

Captain McIntyre isn't present.

He threw to the flag officer himself. Who is this?

Now, Max Horton...

is a big deal he is the head of the royal navy's submarine arm he was a

submariner in world war one he knows everything there is to know about

warfare sir it's commander roberts of the western approaches tactical unit

i wanted to speak with captain mcintyre on submarine tactics i served in subs

during the first war what do you need oh thank you sir

What is the range of a German torpedo?

The G7E.

Roughly 5 ,400 yards, but that's the limit.

Effective range.

Expect to halve that.

Now, remember the ship that was sunk in HG -76?

That ship was in the middle of a convoy. A convoy is 10 ,000 yards across. I

mean, how does that make sense?

Commander, are you still there?

Yes, sir.

One more thing, if I may.

During the first war, would you ever fire from inside the convoy?

Of course.

It's the only way of being accurate.

Inside.

That bloody one inside.

Robert, does this answer your question?

Yes, sir.

More than you can know.

Commander Walker, the Royal Navy, they all believe the U -boats fire from

outside the convoy, but what if they're wrong?

What if they're firing from inside?

The U -boats Walker sank.

It would mean Buttercup is based on a false assumption.

The Royal Navy are relying on luck to protect the convoys.

The Navy knew all along, but they forgot they knew.

Is that Donitz's master tactic?

It's getting late.

Well, Drake, you're dismissed for the evening. Get some sleep.

I want you to stay.

As long as you need, sir.

We need to work out how the Yibbets are getting inside the convoy.

And find a tactic to destroy them.

Mein Fuhrer, I can strike a decisive blow, but I need more U -boats.

U -boat destroyed.

Oh.

Run the game again.

We need to be sure.

Who devised this tactic?

Ren Jean Nadel, sir.

And do you have a name for it?

Raspberry. As in blowing a raspberry at Hitler, sir?

Well, let's hope it works at sea.

Because now Durnick has his 300 U -boats.

And he'll be hell -bent in using them to turn the Atlantic into a convoy

graveyard.

Imagine the carnage we will sow.