Hidden in a fold of Kent countryside, just thirty miles from London,
is the home of Britain's wartime leader - Winston Churchill.
Casting his mind back over five bloody and uncertain years,
he would write that during the war, only one thing ever frightened him.
The U-boat peril.
'Battles might be won or lost,' Churchill wrote,
'but our power to fight, to keep ourselves alive,
rested on the outcome of the struggle for control of the Atlantic.'
lt was one of the longest campaigns in Naval history.
Bitterly fought over three million square miles of hostile ocean.
When it began, the U-boat didn't seem to be a peril at all.
And yet within eighteen months it was able to take Britain to the brink of defeat.
ln 1942, this battle for survival was at its height.
Those lost fighting it have no grave. There are only names.
This series remembers their war.
At a little before midnight on October 13th, 1939,
a lone U-boat slipped through the line of sunken ships
that guarded the entrance to one of the Royal Navy's most important bases.
U-47 was about to attempt what the British believed impossible.
An attack on the Fleet in the safety of its anchorage at Scapa Flow.
lts Commander - Gunther Prien - kept a log of his mission.
'There are warships anchored inshore.
We close to a distance of some three thousand metres.
We will attack the big one.'
She was the thirty thousand ton Royal Oak.
The flagship of the Second Battle Squadron.
That night, the Oak was at anchor at the eastern end of the Flow.
Most of her crew, twelve hundred men and boys, were asleep below.
Suddenly, without any warning at all,
there was an enormous explosion right up forwards somewhere.
lt shook the ship from end to end and l hopped out of my hammock
and l told them all to get out and get dressed
and they just sort of leaned over their hammock and said,
'ah, don't worry about it.'
We were talking, saying, you know, 'What the Dickens was that?'
Somebody thought it sounded like an anti-aircraft gun,
but nobody really knew.
One of Prien's torpedoes had hit the Oak, close to the anchor chain.
Her Captain thought it was a small internal explosion
and that there was no need to rouse the crew.
Two out of every three men on that ship only had twelve minutes to live -
- and they didn't know it.
Prien fired three more torpedoes.
The ship seemed to jump out of the water, you know. lt was an enormous explosion.
The last one set off the cordite magazine and this blast,
hot orange blast came up through the deck -
and l wondered how long it took, you know, to die.
And um, excuse me a moment.
Brings back a lot of memories.
'There was a terrible roaring and cracking.
Columns of water and fire, fragments were flying through the air.
One battleship sunk. Every tube empty. l decided to leave.'
You have to admit,
it was an incredible achievement for Prien and his boat,
with all the great difficulties of navigation he faced.
He managed to get into Scapa Flow and then get out again.
On the Oak,
most of the crew were trapped between the decks as the ship began to capsize.
l must have slipped down many feet and hit the water.
Something touched me on the back of the neck,
l thought blimey, it's coming down on top of me,
and l did the fastest hundred yards l've ever done in my life.
The next thing l remember was um, funnily enough,
my Divisional Officer coming over with a great lump of wood
that he was hanging onto -
and he said, 'Who's that?'
and l said, 'Leading Seaman lnstance and l'm burnt to buggery.'
So he said, 'Oh, bad luck, old man.'
Eight hundred and thirty three men were lost on the Royal Oak.
lt was a national humiliation.
A British battleship sunk at anchor in a place symbolic of the country's sea power.
By the time U-47 returned to its base at Wilhelmshaven,
the name 'Prien' was known throughout Germany.
He had become the 'Bull of Scapa.'
Prien became a national hero,
and the public became very aware of the U-boats and their potential in this war.
Only a month before,
Hitler had been openly skeptical about the value of the U-boat.
Now it seemed to represent just the image of military ingenuity
and courage he wanted to foster in the Reich.
He told Prien he was responsible for a unique triumph.
lf forty four men and a lone U-boat could sink a battleship,
what could a fleet of submarines do?
Prien's mission had been meticulously planned by the staff
at U-boat Command in Wilhelmshaven.
The leader of the U-boat arm, Karl Donitz,
had forged his men into a fighting elite.
Their training was dominated by the prospect of war
with Germany's natural enemy at sea, Great Britain.
The task was to find out how to cut the -
supplies across the Atlantic within a reasonable time
so that may be Britain would get in serious trouble.
When war came, although he commanded just fifty-seven U-boat,
Donitz planned to launch a ruthless sea blockade,
which he believed in time would starve Britain into submission.
Sixty years ago,
this forgotten wasteland was full of ships and merchant seamen preparing
to make the three thousand mile voyage across the Atlantic.
Before the war, some sixty million tons of food
and raw materials passed through ports like Liverpool.
We realised that we were the lifeline.
Without the Merchant Fleet there'd have been no food,
there'd have been no fuel.
Where were all the other forces going to get their stuff from
if we didn't bring it from America?
None of the glamour of the Royal Navy,
but sailors of the finest type for all that.
One hundred and thirty thousand men sailed under the Red Ensign.
How old are you?
Twenty-nine.
They were officially non-combatant,
but these were the men who would bear the brunt of the U-boat attack.
You were directed by what was called the Pool and you had no - choice.
lf they says, take that, SS Maas, Endon Dock, you just went down -
- and signed on.
l joined the Beatus. She was a tramp, a tramp steamer.
She had the smell of sugar and oil on her,
you know, it was - dirty old tramp, they call them.
They never came back to me and said,
'well now, we've got these new ships but we can't can man them.'
There were always coming forward for this very risky and very ill paid and very -
- uncomfortable job.
This nation owes those people a great deal.
Well, it was ourjob.
We knew we were going out, you mightn't come back,
but you never - you never, you never dwelt on it.
From the first,
it was the U-boat rather than Germany's small fleet of warships
that threatened this life-line.
Faith in Britain's ability to protect it,
rested on the most powerful surface fleet in the world - the Royal Navy.
The Admiralty in London was quick to introduce a system of protected convoys.
Merchant ships would be escorted for part of theirjourney by warships.
The busiest convoy routes were those across the North Atlantic to Canada and America.
lt was along these that most of the country's vital imports would pass.
Ships were given their station in a box.
You have several in a row there and several behind them in rectangle.
and you steamed out in a succession which you already agreed from Liverpool,
slowly at first and then gradually getting under way.
Well, you could be looking six mile across the front of the convoy
and you could be looking six mile down the length of the convoy,
so you're covering a fair area with a sixty ship convoy.
We, in the escort, went round at speed looking at all the ships,
checking them by name,
checking they'd got their right positions in the convoy and so on.
Usual thing, eight knots a quarter of a mile apart.
Now let's count them. Three, four, five...
They'd come charging round and er,
at high speed and pull up alongside like, you know.
'You're too far behind' like, you know,
'are you all right? Do you require assistance'
or anything like that and they'd say,
'No, it's just the best - this is our best speed.'
Try to keep up, old man.
Some are slower than others.
The top speed of that Beatus l was in,
all she could do was six knots; you could walk faster.
The weather was dreadful and people were very sick and people went
and just slept in a corner soaking wet from watch
and they were soaking wet when they went on watch again.
lt is a main factor in the Battle of the Atlantic
after trying to kill each other, was the weather.
You'd be on look-out in the masts.
You were looking out for periscopes, which was a hell of a thing.
You know you're looking and - and er, you might see a few, a few porpoise come -
zooming at you. lt would scare the wits out of you,
cos it's just a torpedo coming through the water.
ln the first months of the war,
the U-boat fleet sailed out to the convoy routes from the north German ports.
lt meant a long and dangerous haul across the North Sea and round the British coast.
But the crews were full of confidence.
They were the U-boat Waffe,
the spearhead of the assault on the old enemy.
War patrols would last for as long as there was fuel and torpedoes.
For three weeks or more,
fifty men would be confined to what some called their 'iron coffin.'
The U-boat arm made its own rules.
Donitz believed this would play its part in building
the right sort of fighting spirit in the crews.
There is no uniform onboard and no indication of rank,
just overalls. lt was informal. lt wasn't really the usual military order.
The whole boat smells of diesel. Diesel is ingrained everywhere.
Because there are full tanks there was always something dripping somewhere.
There was no comfort aboard a submarine, no comfort.
Because you share your bunk with another one,
because he has the same - the same job aboard the ship as you have.
For instance, the wireless operator.
He is on watch four hours and you have time to rest-
and then he goes into this bunk.
And this is er - the bunk is still hot, still hot.
Of course it would smell of sweat because no one washed properly.
There was quite a stench sometimes.
lt was mostly boring, you've got to admit that.
Boredom, there was nothing.
A boat would run its course, little by little,
nothing happened from one hour to the next.
The hunt depended on the vigilance of the boat's watch.
Days were spent searching an empty, featureless horizon.
We rode some pretty massive North Atlantic storms
which were really very impressive.
Nobody could see, move, aim at or do anything.
And then there were those occasions
when you suddenly saw a single ship which you would normally have attacked,
but with which you just steer a parallel course.
You couldn't harm each other.
Everybody thought of their own survival during those heavy seas.
Nothing else mattered.
For the convoy,
survival depended on its ability to lose itself in the Atlantic.
Just a moment of carelessness could reveal its position to the hunter.
You got ships that were indisciplined, especially in the early stages of the war.
They were told not to throw over certain kinds of rubbish from the ship's side
because a trailing submarine would pick that up.
And the other thing was a real problem. Er, the coal fire chips.
Stoking up, you could see them from fifty miles away.
And of course the U-boats loved that.
ln the first months of the war, a cameraman accompanied U-99.
The most successful hunter in the North Atlantic.
lts Commander was Otto Kretschmer.
My Captain, Otto Kretschmer, was a - a very intelligent man.
Very cold blooded and er, knew exactly what kind of risk he could take.
At first there were easy kills.
Lone ships traveling beyond the Navy's protection.
But as more ships sailed under the Admiralty's umbrella,
commanders like Kretschmer were forced to run
the much greater risk of attacking the convoys.
This was done at first as it was done during the First World War.
By day we'd expect to enter a convoy underwater,
approach it and fire at it from underwater.
lt was a calm, smooth day, in summer and suddenly the Jersey City went back.
A lovely clear day and so calm one - one should have seen the periscope,
but one didn't.
You went out in an ever widening circle trying to find the submarine by ASDlC.
ASDlC, or sonar, was the new weapon in the Admiralty's armoury.
lts underwater searchlight.
Contact.
A pulse of sound was sent out from the ship.
lf the sound wave struck the U-boat they were reflected back.
This echo gave the range and bearing of the target.
lf convoy was the first pillar of the Navy's defence, ASDlC was the second.
At once there was contact from the ASDlC of this destroyer and er -
he was running right overhead,
you could hear the swish of the propellers
and then he turned and came back and he threw -
- his depth charges.
Depth charges were three hundred pound drums packed with high explosive.
With a fuse that could be set to detonate at different depths.
Within fifty feet of the U-boat's hull, the shock wave would cause damage.
Within twenty, it would kill.
Once ASDlC contact was made - the hunter became the hunted.
The escort destroyers started pursuing us in a very clear and determined manner.
And because we were so very slow underwater,
they had no difficulty in tracking our course.
All instruments were destroyed, you see.
Glasses broken, there is no light anymore only small flashlights.
We went down to this unbelievable depth.
The cook put on a life-jacket and turned up wide-eyed at my command post.
l kept telling him to go back but he didn't.
l said to him, 'Come on, Franz', that was his first name,
'Sit down, give daddy your hand, nothing will happen to you. Come on,'
l said. Then he sat down, gave daddy his hand,
held my hand tightly and calmed down.
Daddy was twenty-four years old.
The boat went deeper and deeper.
Of course, everyone had the feeling this is it.
One second more and there's one big crack and -
you are er, pressed together like an empty tin can.
The air supply became very scarce.
Everyone had to lie down and be still and breath through the oxygen cartridges.
They kept us underwater for seventeen hours.
On this occasion, depth charges were not well aimed enough to be fatal.
We went to depths of 150 metres or more. The depth charges were all above us.
The depth charge fuses were on too shallow a setting.
The U-boat was able to take refuge
at a much greater depth than the Royal Navy thought possible.
Yet at the Admiralty, figures compiled by Naval staff suggested
that merchant shipping losses would be manageable.
ln the first nine months of the war, 215 ships were sunk,
but only twenty-two within the umbrella of a convoy.
The First Lord of the Admiralty, Winston Churchill,
was more than satisfied with the navy's record.
We feel ourselves more confident, day by day,
of our ability to keep open and active the salt water highways
by which we live and along which we shall draw the means of victory.
Our faithful ASDlC detector smells them out in the depths of the sea
and l do not doubt that we shall break their strength and break their purpose.
But in June 1940,
the victories won by Hitler's armies on land were to transform the war at sea.
As Hitler celebrated the Fall of France in Berlin,
the commander of his U-boats was on his way to the Atlantic coast of France.
The ports were all in German hands.
Donitz and his men wasted on time in establishing bases along the west coast.
Here in Lorient,
work began on the huge bomb-proof sea bunkers which would house the U-boat fleet.
For the first time, the U-boats had an open door to the Atlantic.
The situation was now, l would say, the one we'd always wished for.
From his new headquarters in Lorient,
Donitz would direct an all out assault on Britain's lifeline.
The new French bases on the Atlantic coast
would shave almost a fortnight off a U-boat's journey.
Time that could now be spent hunting for convoys.
Above all, they offered the chance for Donitz to introduce his new tactic,
so carefully developed before the war. The pack attack.
This was the beginning of a new phase in the Battle of the Atlantic.
l was anxious that not a day should pass without the sinking of a ship somewhere.
Donitz began to arrange his U-boats into search lines across the convoy routes.
When one of the boats sighted a convoy
it was to report its position to U-boat Command.
lt was not the contact boat, with orders to shadow the target.
U-boat Command was able to direct the rest of the pack to home in on the contact boat.
Donitz was confident that the Royal Navy's defences
would crumble under the weight of a pack attack.
The attack would be carried out at night and in an entirely unexpected way.
One of the first U-boats to be involved in a pack attack in the autumn of 1940,
was Otto Kretschmer's U-99.
A warship comes into view, followed by smoke plumes and the convoy, at last.
We pass a surfacing U-boat, U-101 . l am positioned in front of the convoy.
The pack tactics pioneered by commanders like Kretschmer,
would change the course of the war at sea.
We stayed ahead of the convoy all day long.
And then, in the evening, when it was dark, we dived in front of it.
Then we surfaced inside it.
Through my binoculars l cold see there was a - a shadow of a ship.
But from time to time l could see that someone was er, lighting a cigarette.
Everyone was alert wherever you went and everything
and that night the moon was that wide.
You're thinking, someone's out there.
l went out on the wing of the bridge and there was the um, U-boat,
Well, a hundred yards away with all the officers in the conning tower.
l gave the order to go hard aport, that would put the put the U-boat stern on.
lt's like big game hunting, you have to attack from a forward position.
So the normal distance for torpedo attacks at night -
- is about six hundred metres.
Before l could answer the helm, we were hit.
Everything sort of disintegrated around us.
The concussion shot up your legs, up your backbone,
into your skull and everything, and lifted you at the same time.
l went round to the engine room and -
- looked down the engine room and then there was nothing left.
So everything had collapsed. The engine room was three parts full of water.
Those poor men down below what - let's hope it was very quick,
their death, cos if must be dreadful, must have been dreadful. Dreadful.
l saw the water coming into the wheelhouse, you know, that high,
you know, waist high to me and l'm eventually in it and then under it.
And l was reaching out to rails and pulling myself and trying to get myself clear.
l was panicking. And then suddenly l was making my way to the surface.
And l was coughing and spluttering and l looked around and -
could hear shouts and er, l turned and tried to locate them,
but l wasn't sure what direction they were coming from.
But apparently they were only shouts of lads that were drowning.
What follows now resembles the raging of a wolf in a flock of sheep.
l fire a torpedo at a large freighter.
lt explodes and there is a high column of flame which rips
open the ship from the bow to the bridge.
The propaganda newsreels caught only the ships torpedoed by day.
But by the autumn of 1940, most were being sunk at night.
The wolf packs were using the cover of darkness to attack on the surface.
This was the tactic Donitz would turn to time
and again in his pursuit of victory in the Atlantic.
We can hear torpedoes fired by the other boats.
The convoy breaks up completely. The ships run alone and in small groups.
The largest group includes a tanker. This we shall now attack.
We was carrying er, aviation spirit which is the worst of the lot.
l must have said my prayers more times than the local vicar,
because l was really frightened.
l was on the after poop deck of the ship when we heard -
- that there was a torpedo coming and you could see it when they - when they yelled.
You could see the wake.
There was a two hundred metre high tongue of orange flame and in these flames -
there were human bodies and parts of the ship whirling round
and then falling back into the Atlantic.
l didn't hesitate.
l'd seen the big flames and l jumped straight over the stern
and when l surfaced -
- well, the ship had disappeared in - into flames.
You could hear these - your buddies in the water hollering.
'Save me, save me.' But, you know, you were going by them,
the ship was still in a forward motion.
l asked to come up to the conning tower to have a look -
- at the burning tankers and er, because this was er -
for a navy man who was asked to sink ships, was a wonderful sight.
There was a lot of fuel on the water and gasoline burning.
lt sticks to you because it's - it's petroleum.
l heard a cry for help and l swam to him.
His face was all black, burnt. Oh, he was in a terrible state.
We heard shouts of 'Hitler, help. Hitler, help.'
And then something happened that l thought was terrible.
Standing next to me was the U-boat's second -
officer. He yelled into the night, 'Why do you pigs sail for England.'
l was horrified and l gave him a jab and said,
'What do you expect them to do?
These people are doing their duty, just as you are.'
Those left in the sea watched as the convoy passed on.
The other merchant ships were under strict orders not to stop for survivors.
As we ploughed through them you could hear them shouting,
'help.' 'Help.' We couldn't stop -
and l knew this and l could see over the - just down there,
the little lights on their lifejacket drifting past. Very sad.
The first pack attacks in the autumn of 1940,
caught the Navy's escorts completely off guard.
We realised they were on the surface.
We tried to light up the area so that we could see a submarine,
but we wouldn't know what area to light up.
l remember feeling so helpless when you see these ships being sunk.
We would scurry around and try to find out the submarine,
but the ASDlC was useless.
The underwater detector in which the Admiralty placed so much faith,
was unable to find the U-boat on the surface,
and the U-boat was almost invisible in the Atlantic night.
On the surface the U-boat could wring 1 7 knots from its diesel engines,
and that made it faster than some of the Navy's escorts.
The Royal Navy was prepared to fight a war against a submarine,
but the U-boat was really nothing of the sort.
All the boats we had during the war were actually surface craft
who had just the possibility to dive.
As these boats were depending on batteries,
they were very slow as soon as they were submerged.
Out of about twenty ships l sank,
l mean l sank - sank nineteen at night on the surface.
The Navy rescued those it could,
but survivors in the water made the job of protecting the convoy even tougher.
The main problem of survivors in the water is that
they are usually where the U-boat is and you want to -
depth charge the U-boat and you can't, cos you're gonna kill your survivors.
And that on one or two occasions happened during the war. Very unpleasant.
Er, we heard someone shouting on a loud hailer.
He said, 'l can't stop, l've got scrambling nets over the side -
l can't stop, U-boat in the area,
you'll have to jump for it and scramble aboard.' And we did.
They carried us down to different parts of the ship
and l remember going to this particular mess, l don't know,
and er, we laid on a - laid on a bunk and they brought hot coffee round.
Oh God, it was so beautiful.
ln just two nights in October 1940, a pack of five boats sank twenty ships.
Even well protected convoys appeared powerless
to prevent the wolf packs sinking at will.
By the end of the year, more than a thousand ships had been sunk.
Six thousand merchant seamen lost.
On the Atlantic coast of lreland, the human cost was all too obvious.
The first body that came in was over in them rocks over there.
The boat must have been sunk off away out in the Atlantic some place
and the body was washed in here.
There was a disc on him.
And his number was on it, l don't - couldn't tell you the number,
but l know the name, he was a Sergeant Derby of the Marines.
Then there was other bodies.
One body came in and it was badly decomposed.
We had a bit of a cliff to climb and he had to be tied on to a stretcher -
And soon as we put the legs over on the body,
the stomach collapsed, bursted and there was a terrible smell.
Oh, you would nearly throw up.
And then we took him to this hotel that - where the bodies was all usually was taken.
lt was very sorrowful. l mean we were - a lot of us there was,
well we were sad but we couldn't do,
we had a job to do and we done it and that was it.
This was what the U-boat men called their 'happy time.'
On the journey home to their French bases, the crews prepared their victory bunting.
Each flag marked with the tonnage of a ship sunk.
No more than six boats were operating against Britain's lifeline at any one time.
Just three hundred men.
Much was being asked of a handful of U-boat crews.
ln return, Donitz ensured that they were very well rewarded.
This was notjust a 'happy time' at sea.
The crews were to enjoy the best of life ashore.
A hundred thousand bottles of wine were requisitioned by Donitz for his men.
'Onkel Karl' cared.
There were special food parcels. U-boat hotels, and extended leave.
Usually we would seek out some dive and then of course
if there were girls present we would try to dance with them.
Sometimes we even succeeded.
l can still remember, what was the price of a bottle of champagne?
l think it was twenty Francs, which was no money at all to us.
Of course we did have a good life, yes and we would make the most of it, too.
lt was a very different sort of homecoming for the British seamen
who'd survived the wolf packs.
We got a roll call -
any survivors off one ship, this ship and that ship,
and it come down to Creekirk, and l don't why,
when l went up later on l said, 'did anyone come forward?'
He said, 'No, apparently they've all gone with the ship.'
So l knew, that was two of me friends and neighbours,
they were dead, l knew that.
l put me arms - put me arms around me mother
and l couldn't tell her about Eddie and Billy till the next day and l said to her,
'whatever - whatever you do, mum, don't tell their people,
leave it till they get a telegram.'
So my mother knew, she knew that they weren't coming back,
they didn't know where they were, their mothers.
ln Germany, the propaganda ministry made heroes of those
it called 'The Grey Wolves.'
That winter the Commander of U-100.
Joachim Schepke, took his men on a skiing holiday in the Bavarian Alps.
The U-boatmen were the guests of the grateful village of Ruppolding.
They lived with the villagers; the Commander with the Plenk family.
ln those days it was Prien, Kretschmer, Schepke.
They were for us boys so to speak the heroes.
The U-boat heroes.
And we were proud of having one of them staying in our house.
That goes without saying.
The reception was naturally magnificent.
l can remember that there were folk evenings at the Kurhaus,
as is the tradition here.
They were certainly unforgettable days for the crew.
l can remember we were all very proud.
As 1940 drew to a close, the British public felt under siege.
l get along without sugar. l never drink any tea. Eggs and bacon...
Before the war, the country imported twenty-two million tons of food.
By November, that figure was running at less than twelve million.
One thing l always crave, and that's why hear me sing,
oh when can l have a banana again? Oh tell me, tell me mother...
The ration book became the key to survival for nearly every household in the country.
You got two ounces of tea each and me mother loved tea
and you only got one egg a week and you got very little cheese.
Very little meat. You'd have to look for the meat.
lt was hard to - to manage, you know.
Sometimes the word would go around, oh there's er,
there's something in Postlethwaites and that was a fruit shop...
All the women would be scurrying up
and l say we'd stand in a queue and you wouldn't actually know
what you were standing in the queue for.
And l'd say - we'd say, 'What is it, what is it?'
And the man would come out all stern, you know.
'lt's one orange and don't anyone ask for two.'
And you'd be so thrilled to get an orange.
Vegetables weren't rationed so you eat more vegetables.
So if you eat potatoes you didn't need as much bread.
They'd tell you that merchant seamen had to risk
their lives to go to Canada to bring the wheat to make the bread.
So if you eat potatoes you were helping your country.
...all well known to the enemy.
And we must expect that Herr Hitler will do his utmost to prey upon our shipping,
his clutching fingers reach out on both sides of us into the Ocean.
l have never underrated this danger.
ln Winston Churchill's private office,
a small team of economists was responsible
for keeping him informed on matters of shipping and imports.
Churchill would pour over their weekly bulletin.
He later wrote of the 'measureless peril' expressed in its charts,
of figures showing 'potential strangulation.'
An index l compiled of stocks of imported food
and raw materials measured in tons er -
was falling rapidly towards a really, a dangerous level.
And l think a lot of people didn't realise how worrying it was.
lt was hardly an exaggeration to say we could have -
- lost the war on the home front at that time.
ln January, 1941 ,
Hitler spoke to the Reich of his confidence in his 'Grey Wolves.'
Just a handful of U-boats had helped bring Britain to the brink of defeat,
and now more boats were being built.
Donitz's packs would be able to range further into the Atlantic,
and in greater numbers.
The tonnage war,
the race to sink more ships than Britain could buy or build had begun.