Original subtitles

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As World War II got underway,

both the Allies and the Germans

were looking for the knockout blow.

The new weapon that would decisively

defeat the enemy.

For Hitler's Germany the problem was

that Britain was an island.

His tanks couldn't blitzkrieg across the channel.

The only way to defeat her was to

strangle her seaborne supply routes.

That meant warships and above all, submarines.

For the Western Allies, the problem was attacking Germany

when there were no Allied troops in mainland Europe.

The solution they adopted was strategic bombing.

Aerial bombardment, aimed at destroying

Germany's infrastructure and pounding

its people into submission.

The two sides had adopted two very

different tactics but with one aim.

To save their troops and to bring the war

to an end as quickly as possible.

Ironically, it was the Germans

who first started strategic bombing.

In August 1940, Luftwaffe bombers accidentally hit London.

The RAF retaliated by bombing Berlin.

By the autumn, Germany was bombing

Britain's cities almost daily,

convinced the British would eventually crack.

But the Blitz, as it was called,

never showed any sign of forcing

the British to surrender.

And by the summer of 1941, it was dying away

as the Luftwaffe turned its attention to the war in Russia.

But for the British military command,

bombing remained the only way of

striking directly at Hitler's Germany.

Moreover, by early 1941 the RAF was starting

to receive a new generation of bigger,

more powerful, four-engined bombers.

These could carry loads of up to 18,000 pounds of bombs,

four times the capacity of earlier aircraft.

The first of these was the Short Stirling.

To begin with, the plan was not

to hit the German population,

but specific infrastructure targets,

cutting transport and oil supplies,

damaging Germany's ability to wage war.

But it suffered one central problem.

Britain's bombing was extremely inaccurate.

In August 1941, a secret British report showed that

over the crucial German Ruhr industrial area,

only 10% of British bombers were getting

their bombs within five miles of their target.

At the same time, the German air defences

were taking a terrible toll on British planes.

By late 1941, up to 10% of the bombers

on any raid were being shot down.

A loss rate which couldn't be sustained.

The Royal Air Force High Command

decided to change tactics.

It gave up any pretence of trying to hit specific targets.

Instead, Bomber Command was instructed to undertake

what it called "area bombing."

A euphemism for what is known today as carpet bombing.

The idea was to deliberately target an entire area

of a city, regardless of the civilian population.

In the chilling words of the British Air Ministry,

it would destroy "the morale of the civilian population"

and, in particular, of industrial workers."

Its leading exponent was Air Marshal

Sir Arthur "Bomber" Harris,

who was now appointed commander-in-chief

of RAF Bomber Command.

There are a lot of people who say

that bombing can never win a war.

Well, my answer to that is that it has

never been tried yet and we shall see.

They sowed the wind and now they are

going to reap the whirlwind.

In spring 1942, Harris launched what was, in effect,

a huge public relations stunt for

what he preferred to call, "strategic bombing."

He gathered every available aircraft in Bomber Command.

Over a thousand took off for the German city of Cologne.

The city's defences were overwhelmed.

Six hundred acres were destroyed.

But only 39 British aircraft were lost.

Harris had won his point.

He now had the full support of the

British prime minister, Winston Churchill.

He also now had an outstanding new weapon,

the Avro Lancaster, the finest

heavy night bomber of the war.

And he had a new partner.

By the summer of 1942, the United States

had joined the air war in Europe.

American planes began to appear in Britain.

The majority were the Boeing B-17 Flying Fortress.

It was heavily armed with 13 machine guns

and could, in theory, fight its way through

to a target in daylight without a fighter escort.

It was also equipped with a new bomb sight

that would supposedly allow it to drop its bombs

with almost unerring precision.

These features encouraged the Americans

to ignore the lessons of the early British campaign

and return to targeted raids on Germany's infrastructure.

In August 1942, the Americans put

the Flying Fortress to the test.

Twelve of them attacked marshalling yards

near Rouen in France.

Damage was slight, but the United States lost no aircraft.

For the Americans, it was the proof that daylight raids

on infrastructure targets could work.

For the British, it simply showed that the Americans

could hit a minor and relatively undefended target.

But that winter, the two Allies

agreed to combine their approaches.

They would launch a massive bombing campaign

against Germany's industrial heartland.

The Americans would attack by day against

carefully selected infrastructure targets.

The British would attack by night,

carpet bombing whole areas,

destroying war production and civilian morale.

They hoped it would be so devastating

it might even bring the war to an end.

In March 1943, British planes took off

for the German industrial city of Essen.

High-speed mosquito light bombers went in first,

dropping flares to highlight the targets.

Then a force of nearly 450 Lancaster bombers

swept over the city, dropping their loads.

The German defences were overpowered.

Only 14 British aircraft were shot down.

The Essen raid was followed by wave after wave

of similar attacks on industrial towns in the Ruhr.

But the German air defences now began to

get the measure of the Allied attacks.

Britain's losses climbed to one in ten.

Harris was forced reluctantly to call a halt to the attacks.

But then he was informed about a new Allied invention.

Code named "Window," it consisted of clouds

of aluminium foil strips dropped from an aircraft.

As the foil fell, it jammed any radar system.

It promised to cripple the German air defences.

Harris seized on it.

And four months after the Essen raid, in July 1943,

he went back on the offensive.

He called it Operation Gomorrah.

The target this time was the industrial port of Hamburg.

Bombers, equipped with Window, jammed the German radar.

Other aircraft dropped incendiary bombs.

A giant firestorm engulfed the city's centre.

Forty thousand people died and half a million

were made homeless.

More raids on the port followed.

It was an enormous shock to the German people.

Four months later, in the autumn of 1943,

Harris followed Hamburg with a series of attacks on Berlin.

But by now the Germans were learning to overcome

the effect of Window and by spring 1944,

British losses were back at nearly one plane in ten.

Worse, there was no sign

German civilian morale was cracking.

Harris's carpet bombing campaign was just not working.

But neither was the American alternative

of targeting infrastructure.

By the spring of 1943, US Army Air Force daylight raids

were steadily reaching deeper into Germany.

But American losses were climbing.

Around one in every 15 planes was being shot down.

Yet, undaunted, the American command now launched

an attack on factories in the German towns

of Regensburg and Schweinfurt.

It was hugely ambitious.

Both were deep in southern Germany,

far beyond the range of US escort fighters.

It was a disaster.

The 380 Flying Fortresses, which US bomber chiefs

had assured everybody wouldn't need a fighter escort,

were harried and shot down.

The loss rate was over 16%.

The US was forced to suspend its bombing campaign.

The war in the air had reached stalemate

and there was still no sign of it

helping to usher in a victory.

Then, in the early summer of 1944,

as the Allies prepared to invade mainland Europe,

the British and American air forces were tasked

with disrupting German communication

lines and oil supplies.

It represented a return to targeted infrastructure bombing.

But this time, the Allies had a new weapon.

The British had experimentally modified

a US fighter, the P-51 Mustang.

The US engine had been replaced by

a British made Rolls Royce Merlin.

It gave the plane a much longer range.

It was the ideal long-distance bomber escort.

The Allied bombers hit bridges and roads

leading to the German front in France

with almost surgical precision.

Oil supplies to the German military

were drastically reduced.

Once again, the German fighters attacked,

but they were now out manoeuvred by the Mustang.

Much of the German air force,

now running low on fuel, was grounded.

The campaign of targeted bombing

on Germany's infrastructure may not have been

the knockout blow the Allies hoped for,

but it was finally paying dividends.

But one man was not impressed.

Bomber Harris was still obsessed with the idea

that ever more devastating carpet bombing attacks

would stop Germany in her tracks once and for all.

So it was, that in late 1944,

Britain returned to carpet bombing.

German city after city was hit and devastated.

Then, in February 1945, Harris attacked Dresden,

a city with virtually no military significance.

The city's civilian population had been inflated

by refugees fleeing bombing raids elsewhere.

Yet Harris seems to have had no regard for civilian life.

The city was flattened.

Some 50,000 people died.

It was a raid too far.

Finally questions began to be asked about the morality,

let alone the efficacy, of carpet bombing.

Whatever it had achieved, it had been done at a horrendous

cost of civilian and military lives.

Critically, it had failed to break German morale,

yet 60% of RAF crews had died

before they had completed 30 missions.

For all the hopes put in it,

carpet bombing had not come up with the knockout blow.

The Germans, meanwhile, had put their faith

in an altogether different technology

to give them the knockout blow they needed to win the war.

For Germany, Britain was a problem.

It was an island and, for once,

Hitler's formidable land forces were useless.

Britain also had a much more powerful navy.

Yet Hitler calculated that if he used

what he had strategically, he could fatally

disrupt the sea convoys that were keeping

Britain supplied with everything from oil to food.

In the first 18 months of the war,

German raiders sank more than 130 British merchant vessels.

Some of the most effective raiders

were the so-called, "pocket battleships."

Small but powerful warships designed in the 1930s

to circumvent restrictions imposed on

German rearmament after World War I.

One, the Graf Spee, became particularly notorious.

In a matter of weeks she sank nine Allied merchant ships

in the South Atlantic before being cornered off

the River Plate in South America and scuttled.

But the raids were taking a serious toll.

If the losses continued to rise,

Britain would have real supply problems.

Then, in early spring 1941, Germany's first and only

two full-sized battleships completed their sea trials.

They sent a shiver through the British Navy.

Their potential for destruction was enormous.

First into action was the Bismarck.

In May, RAF reconnaissance aircraft

spotted her in the Norwegian port of Bergen,

trying to sneak out into the North Atlantic.

The British Navy set off in pursuit.

Two days later, the Bismarck was

sighted in the North Atlantic.

Britain's latest battleship, the Prince of Wales,

was sent to intercept her.

With her was the British battle cruiser, Hood.

Early on May 24, 1941, the two forces met.

It was the first time the two sides' battleships

had squared up to each other.

Almost immediately, a shell from the Bismarck

plunged through the weak deck armour of the Hood.

It penetrated one of the aft magazines.

There was a huge explosion.

Only three of the Hood's 1,200 crew survived.

The Prince of Wales, now outnumbered, retreated.

It was round one to the Bismarck.

Two days later, Bismarck was spotted again.

This time far to the south,

several hundred miles off the coast of France.

British Swordfish torpedo bombers swooped in.

One hit and jammed the Bismarck's rudder.

The following morning, two British battleships,

the Rodney and King George V,

caught up with the crippled Bismarck.

They started pouring heavy calibre shells

onto the hapless German ship.

She was soon reduced to a blazing wreck.

Bismarck was finally sunk by a torpedo.

All but 110 of her 2,300 crew perished.

The Bismarck had been sunk before

she'd had a chance to prove her worth.

Then in June 1941, Hitler invaded the Soviet Union.

War at sea entered a new phase.

Britain began sending supply convoys

to the Russian Arctic ports of

Murmansk and Archangel.

Immediately the German navy prepared to cut them off.

Convoy after convoy was attacked or threatened.

By summer 1943, it had become so dangerous,

further convoys to Russia were suspended until the autumn,

when it was hoped bad weather and

poor visibility would offer some protection.

While the convoys were suspended,

Britain turned its attention to one

of the biggest threats it faced,

the Bismarck's sister ship Tirpitz.

She'd spent months hiding in the Norwegian fjords

waiting for the moment to pounce.

All the while the British Navy had been

keeping her under close watch,

determined to eliminate Germany's last battleship.

In September 1943, five British midget submarines,

known as X-craft, were sent into

the Norwegian fjords to sink her.

The attack caused only minor damage

and by the following spring, the Tirpitz was,

once again, ready the menace the Arctic convoys.

The Royal Navy now sent in a massive force to attack her.

It included six aircraft carriers.

They took the Germans completely by surprise.

British dive bombers attacked Tirpitz.

But she was heavily armoured and the relatively

small bombs caused only superficial damage.

Three months later she was ready for action again.

She was soon spotted in another Norwegian fjord.

Lancaster bombers carrying massive five-ton Tallboy bombs

were sent in to sink her once and for all.

Tirpitz put up a smoke screen which partially obscured her.

Nevertheless several bombs struck her bow

causing severe damage.

Finally, two months later, a squadron of Lancaster bombers

caught her in perfect weather conditions.

Three Tallboys struck home.

Tirpitz slowly capsized

Almost a thousand crew members went down with her.

After more than two years of hiding and running

from the British navy, she had been sunk.

Germany's battleships had promised much,

but against the overwhelming might of the British navy,

they'd never had a chance to prove their worth.

Hitler had lost the battle at sea,

at least on the surface.

But below the waves, it was a different story.

Germany's military planners had long expected

that the country's U-boat fleet would play a key role

in cutting Britain's supply lines.

They could sneak up underwater on British merchant vessels,

attacking them at the last moment.

The submarines were also extremely agile on the surface.

To combat the threat, Britain's merchant fleet

was corralled into convoys for protection.

But there was a serious shortage

of anti-submarine ships to escort them.

Many ships sailed without protection.

Yet Britain's naval command remained remarkably complacent.

They believed they had the weapons

and the technology to contain the U-boat threat.

It was soon proved wrong.

In the early months of the war,

Britain's supply lines were harassed and disrupted.

Often the U-boats would attack on the surface,

picking off merchant ships with their deck guns.

In response, the Royal Navy sent aircraft carriers

equipped with submarine hunting aircraft

to patrol the sea lanes used by the convoys.

But they had only limited effect.

By the end of 1939, over a hundred Allied merchant ships

had been sunk by German submarines.

If losses continued at this rate,

Britain would face disaster.

Oil, food, and weapons would all begin to run short.

Then things got even more difficult.

Germany overran France.

Suddenly the German Navy, which until now

had been largely bottled up in the North Sea,

had access to France's Atlantic seaboard.

They now had a base to attack Britain's Atlantic convoys.

France's Atlantic ports filled with

newly built German U-boats,

particularly the Type VIIC ocean-going vessel.

Admiral Karl Doenitz, head of the German U-boat service,

now organised his submarines into what he called Wolfpacks.

A group would be lined up across a likely convoy route.

As soon as one U-boat spotted a convoy,

it called in the rest to attack.

Sometimes the U-boats were also guided

by long-range patrol aircraft.

By the end of October 1940, up to 40% of Allied

merchant shipping per convoy was being sunk.

Britain's supplies were under threat.

German U-boat crews called it the Happy Time

and top U-boat commanders became national heroes.

Britain was paying dearly for its lack of preparation.

But, finally, things began to change.

A crash building program of anti-submarine

escort vessels was producing results.

The first Corvettes, as they were known,

were coming off the slipways.

For the first time, Britain could set up

permanent groups of warships to escort the supply convoys.

But their effectiveness was limited by the fact

that their top speed was 15 knots,

two knots slower than the surface speed of a U-boat.

At the same time the patrol aircraft of Britain's

Coastal Command were equipped with depth charges.

They lacked the range to cover the mid-Atlantic,

but U-boats on the surface near their bases

could be harried and forced to submerge.

Then, as in the bombing campaigns,

it was a series of technological breakthroughs

that really came to Britain's help.

In early 1940, a new type of radar,

known as centimetric radar, was developed.

It was smaller than existing systems and,

for the first time, could be fitted

to escort ships and aircraft.

Now any German U-boat on the surface was vulnerable.

Some months later,

there was a second technological breakthrough.

Huff Duff was a radio detector.

Any time a German U-boat surfaced to communicate,

Huff Duff could pick up the radio signal

and pinpoint its exact position.

Steadily, during the spring of 1941,

Britain began to contain the U-boat threat.

Merchant shipping losses fell by more than half.

In early March, Guenther Prien,

one of Germany's top U-boat commanders,

failed to return from a patrol.

Shortly afterwards, two more top German U-boat

commanders lost their lives in quick succession.

Then Germany suffered a major disaster

that would reverberate through the rest of the war.

In May 1941, the British destroyer Bulldog forced

U-110 to the surface and captured the submarine.

On board was an Enigma machine,

used for encoding German signals.

More importantly, Bulldog also captured

the naval code books that went with the machine.

It would provide vital assistance

to Britain's code breakers.

Soon, unbeknown to the Germans,

Britain was getting a real insight

into German naval communications.

For the Royal Navy, it meant convoys could now be

routed away from the U-boat Wolfpacks.

Germany's submarines had to work harder

and search further to find and sink their prey.

Yet, despite the Allied gains, by the winter of 1941

the German war machine was producing

ever greater numbers of U-boats.

The long term outlook for Britain's supply routes

still looked ominous.

Then, in December 1941,

the war at sea changed decisively.

In December 1941,

Hitler declared war on the United States.

Almost immediately, Admiral Doenitz,

head of the German U-boat service,

sent submarines to attack US merchant shipping

along the American seaboard.

At first, only a few of his submarines,

the new Type IX, were capable of making

the long voyage from Europe.

They found easy pickings.

The US Navy's commander-in-chief,

Admiral Ernest King,

had resisted British advice to coral

his merchant ships into convoys.

Over a three month period, more than 400 US merchant

ships were sunk or destroyed.

America was learning the tough lesson

Britain had already learned.

Something had to be done.

King now changed his mind and by May, 1942

the United States had introduced

a limited system of convoys.

By July, the US losses were falling.

It forced the Germans to adopt a new tactic.

They would concentrate their U-boats

in one particular part of the North Atlantic,

the Black Gap, the area in mid-ocean, too far

from land for anti-submarine aircraft to reach.

Often a convoy would be hit by more than

fifteen submarines coming at it in waves.

During October 1942, fifty-six Allied ships

were sunk in the Black Gap.

By the following March, Allied losses had reached

a hundred and twenty ships in a single month.

During the same month, the Germans lost only 12 U-boats.

Hitler's tactic of disrupting Britain's supply lines

so severely the country would collapse,

seemed a real possibility.

It looked as though his U-boats might win him the war.

But now the Allies began to up their game.

Britain had brought in a new commander.

Admiral Max Horton was former head of the

Royal Navy's submarine fleet.

His first move was to set up permanent groups

of destroyers and frigates that would provide

additional support to convoys,

rushing in as soon as an enemy Wolfpack was spotted.

Equally importantly, a string of yet more

technological developments came on stream.

The Hedgehog was an anti-submarine mortar

that fired 24 bombs.

Allied aircraft were fitted with a new

high-powered searchlight, the Leigh Light.

As an aircraft swooped in, it could be

turned on at the last moment, catching

a submarine by surprise on the surface.

2-9-5.

Fire!

The steady technological

advance now began to pay off.

The German U-boat losses increased.

The German commander, Admiral Doenitz,

struggled to regain the initiative.

In April, he ordered an all out U-boat attack

on Convoy ONS5, a convoy of 43 merchant ships

travelling from Liverpool to Canada.

It was designed to be a demonstration

of German naval force.

Forty U-boats descended on the convoy.

The British sent in extra support groups.

Anti-submarine aircraft flew from Canada.

It would take four days for the the Allies

to beat off the German attack.

Eleven merchant ships were sunk,

but the Germans had lost seven U-boats.

Two weeks later, Doenitz tried again,

attacking a second convoy.

It was a disaster.

Five U-boats were sunk without

a single merchant ship being lost.

During May 1943, a quarter of all

Germany's operational U-boats were sunk.

The Germans were finally beginning to lose

the U-boat war in the Atlantic.

So the Allies now took the battle to the Germans.

A new long-range version of the US B-24

Liberator bomber was introduced.

It could now reach the German U-boats in the Black Gap.

Germany's submarine designers tried to respond

with innovations of their own.

U-boats were fitted with radar detectors

and anti-aircraft guns.

Some were also fitted with the Dutch designed Schnorkel,

an air inlet that meant that submarines

could spend longer underwater,

hidden from Allied radar.

But it was too little, too late.

The Allies still found them.

Hitler's U-boats were now pinned down in port.

It was too dangerous for them to roam the ocean freely.

German attempts to find an answer

became increasingly desperate.

They now produced a revolutionary new submarine.

It was known as the Type XXI.

It was electric powered and capable

of 17 knots while submerged,

over twice the speed of a traditional submarine

and fast enough to out-run most surface vessels.

But again, it was too late.

Only one ever became operational

and it never made contact with the enemy.

By the end of 1943, the Allies dominated the Atlantic.

It was a turning point in the war.

Hitler's U-boat campaign had taken

a terrible toll on both sides.

The Germans lost nearly 800 submarines.

Seventy-five percent of the U-boat crews perished.

On the Allied side, some 32,000 sailors died.

But now, at last, with the U-boats out of the way,

great waves of US troops and equipment

could flood across the ocean in preparation

for the invasion of Europe.

Victory in the Battle of the Atlantic would fundamentally

change the course of the war.