Nazi Megastructures "Series 1" (3/6) : U Boat Base
For educational purposes
To create a safe haven in port for their lethal U-boat submarines, the Nazis built massive, impenetrable submarine pens that still survive today.
To create a safe haven in port for their lethal U-boat submarines, the Nazis built massive, impenetrable submarine pens that still survive today.
Category
📚
LearningTranscript
00:00They're among the largest surviving structures of World War II.
00:05It's one of the biggest construction projects ever attempted anywhere in the world.
00:10A series of indestructible bomb-proof fortresses.
00:13I mean, that's the thickness of three stories of solid concrete.
00:19Built to protect one of Nazi Germany's deadliest weapons.
00:23The U-Boat War was the only thing that frightened Churchill about the war.
00:28It was sabbing Britain of its strength.
00:31This is the story of Hitler's Nazi U-Boat pens.
00:34This system is unique.
00:36There's nothing like it anywhere along the Atlantic coastline.
00:40Order them to close immediately.
00:41The aces that called them home.
00:44They were running out of stores that would keep the crew fit and healthy and capable
00:47of actually fighting.
00:48Alarm!
00:49Aircraft are taking on the port bow!
00:51And an Allied campaign to smash them all.
00:54This is an absolutely incredible feat of defensive construction.
01:02The biggest construction projects of World War II.
01:06Ordered by Hitler to secure world domination.
01:10Now they survive as dark reminders of the Führer's fanatical military ambition.
01:15These are the secrets of the Nazi megastructures.
01:24Commands.
01:44The Atlantic Ocean.
01:46Torpedo 25 knots.
01:501940.
01:53Allied Captain Gunther Prien is on his 7th patrol, leading a wolf pack of Nazi submarines
01:58into battle.
01:59Range 500.
02:00Range 500.
02:01Their mission?
02:02To destroy Allied merchant ships carrying vital supplies to Britain.
02:12Keep it steady.
02:15The outcome of the war depends on whether these convoys get through.
02:22If the U-boats can stop them, then the Nazis could win.
02:26Fire!
02:27Fire!
02:28Los!
02:29Yeah!
02:30Sinking 730 Allied ships in the first two years of war, Prien and the wolf packs are
02:43a deadly unseen threat below the waves.
02:48And when they surface back at base, they turn from unseen to indestructible.
02:57Because home is one of the greatest fortresses ever built.
03:02The Nazi submarine base at Lorient was one of the most formidable defensive structures
03:07on the planet.
03:08Naval historian and author Dr. Glyn Prussell is exploring that base to uncover its incredible
03:14secrets.
03:16This whole site covers more than 50 acres, and at the time it was incredibly ambitious.
03:21It was one of the biggest construction projects ever attempted anywhere in the world, second
03:25only perhaps to the Hoover Dam in America.
03:27And I think it perfectly illustrates the ambitions of the Nazi regime to dominate both at land
03:33and at sea.
03:36The transformation of this peaceful French fishing port into a huge Nazi submarine base
03:42was the brainchild of one man.
03:49June the 22nd, 1940.
03:52Hitler's forces have rampaged through Europe, and now the surrender of France completes
04:00Nazi domination of the continent.
04:03But 480 kilometers away, one German commander is focused on his own mission.
04:13Admiral Karl Dönitz is the commander of the German Navy's U-boat force.
04:19Convinced that U-boats can win the war in the West, he's personally searching the newly
04:24conquered French coast for somewhere to base his submarines.
04:30At this stage of the war, Britain was standing alone against Germany.
04:34And of course, Britain's weakness, its Achilles heel, was the fact that it needed to import
04:39raw materials for industrial production, food to feed its population.
04:43So cutting off shipping, blockading the whole of Britain, would bring Britain to its knees.
04:49After the Germans defeated the French army and occupied France, they now controlled a
04:54coastline stretching all the way from Norway to the Bay of Biscay.
04:59Instead of having to sail all the way from bases in Germany, now Dönitz had bases in
05:07France.
05:10The bases in France gave the U-boats ready access, safer access to the Atlantic.
05:17With direct access to the ocean, Dönitz believes he has the chance to destroy Britain's naval
05:22supply lines.
05:24He quickly selects the best sites to locate his new bases.
05:29But the greatest of them all is Lorient, the Brittany fishing port which becomes his strategic
05:37command post.
05:42Dönitz wants to turn the port into an indestructible fortress, so that he can protect his precious
05:47U-boats and keep them operational.
05:49The challenge is that unlike modern submarines, U-boats constantly need to return to base.
06:03Modern nuclear submarine can go on patrol for months at a time because of the nature
06:06of its nuclear technology.
06:09U-boats are very different.
06:10Using the combination of diesel engines, electric motors and batteries, they can only really
06:14go to sea for a matter of weeks.
06:17Because as the fuel ran out, they would have to return to base.
06:21And these weren't very big crafts, so there was a limited amount of fresh water and food
06:25that they could store on board.
06:26So that was almost just as important, the fact that they were running out of the kind
06:30of stores that would keep the crew fit and healthy and capable of actually fighting.
06:35Once their stocks of food and torpedoes run out, U-boat captains like Gunther Prien must
06:40dock for fresh supplies.
06:44How did it go?
06:46Good.
06:47More torpedoes and I would have given you some more prices.
06:50You'll have your chance.
06:54By September 1940, Prien is already a hero in Germany, after sinking a British battleship
07:00at the start of the war.
07:03Now Prien and his fellow commanders receive a further boost.
07:07The new base at Lorient opens for U-boat repairs.
07:11There's not a drop of fuel left, we were running on fumes and we need a full complement of
07:16torpedoes including aft.
07:20As well as being resupplied, each U-boat must be carefully inspected every time it returns
07:25from patrol.
07:26But how do you get something that weighs over one million kilograms out of the water?
07:33The first answer for the Nazis is to use Lorient's existing facilities.
07:40To properly protect Dönitz's precious U-boats, the base needs to evolve.
07:45So the Nazis engineered a second solution.
07:49The U-boats will be brought along these rails and into this building here.
07:55Sixteen metres wide, with walls over one and a half metres thick, these two structures
08:02built in just four months, are the first covered repair bunkers at Lorient.
08:13This is actually the original trolley that U-boats laid on.
08:17It's been modified to take the weight of larger boats by building these extra struts along
08:21the side, but it's basically the same equipment.
08:25And you can see just how important it was to be able to get at the hull, to make it
08:29accessible for all those really crucial repairs.
08:35What makes these buildings vital in the early days is the protection offered by their arch-like
08:39construction.
08:40From up here, you can quite clearly see the distinctive shape of the bunker, with its
08:47curved roof and steep, sloped walls.
08:53Built this way with the intention that any bombs dropped from the air would simply bounce
08:57off the sides.
09:00Without another name for it, the Germans began to call it a Dombunker, literally Cathedral
09:05Bunker in German, and it's easy to see why.
09:11Despite the fact that they are still in use today, the Dombunkers are a temporary fix.
09:16They're only big enough to hold smaller U-boats, and not the large vessels that Dönitz plans
09:21to build.
09:30What Dönitz dreams of is a base made up of gigantic submarine pens, encased in indestructible
09:36concrete bunkers, to protect and supply his fleet.
09:43And to completely sever the link between Britain and America, he also needs hundreds more U-boats.
09:50How many?
09:51Enough?
09:52Enough batteries?
09:53Enough batteries?
09:54Five?
09:55Six?
09:56Admiral Dönitz needed many more U-boats.
10:01He believed that if he had 300 U-boats, with a third of the force at sea at any one time,
10:08he would actually be able to cut off Britain from its overseas supplies.
10:11But at the start of the war, Germany and specifically Admiral Dönitz only had 22 ocean-going U-boats
10:18to fight his campaign against Britain.
10:23But Dönitz's belief that U-boats hold the key to winning the war is not shared by Hitler.
10:29The way Hitler understood naval power was as the battleship, because these were prestige
10:38vessels, vessels that projected the image of Nazi power abroad.
10:44This was a man who used to sketch images of battleships in his spare time.
10:49He thought naval power were big surface ships with big guns, not tiny U-boats under the
10:56surface.
10:58To change Hitler's mind, Dönitz is relying on U-boat commanders like Gunther Prien to
11:04prove that his submarines are war-winning weapons.
11:08And on the 19th of October, 1940, Prien does just that.
11:3960.
11:40Angle on the bow 60.
11:44Keep it steady.
11:52Torpedo 25 knots.
11:54Torpedo 25 knots.
11:59Range 500.
12:01Range 500.
12:09Torpedo speed 25.
12:11Range 500.
12:13Tube 1 is ready.
12:15Stand by.
12:23Fire!
12:25Go!
12:29Torpedo running.
12:38Torpedo running.
12:56In just 48 hours, Prien and six other U-boats attack two convoys, sinking 34 Allied ships.
13:05These were exactly the sort of successes that Dönitz needed.
13:09So all that tonnage that went to the bottom was a ship lost and resources lost.
13:15In other words, they were sapping Britain of its strength.
13:18But would these successes be enough to get Dönitz what he wants?
13:24On the 25th of October, 1940, Dönitz goes to see Hitler, determined to change his mind about U-boats.
13:32But we have a weapon capable of dealing Britain a mortal blow at her most vulnerable spot.
13:38The U-boat war, however, can only be successfully waged if we have sufficient numbers available.
13:44The minimum requisite total is 300 U-boats.
13:48300.
13:54You need 300 new U-boats.
13:59Now tell me about these concrete pens.
14:03I am assured there will be completely bomb-proof, my Führer.
14:09You'll have your U-boats and the concrete pens.
14:14I'll see to it you need take no further steps.
14:21Hitler could no longer ignore the success of U-boats.
14:27Not long after the meeting, he orders an increase in U-boats.
14:31A 200,000-square-metre site is chosen on the Kerroman Peninsula, opposite Dönitz's HQ.
14:38The Kerroman base, the collection of bunkers, represents around a million cubic metres in simple terms.
14:46The Kerroman base is the largest bunker in the world.
14:50It is the largest bunker in the world.
14:54The Kerroman base, the collection of bunkers, represents around a million cubic metres in simple terms.
15:01The Kerroman base is the most important construction by the Nazis in all the occupied countries.
15:13Work begins on the base with the first of two bunkers, K1, in February 1941.
15:21Their construction will eventually consume a quarter of all the concrete used by the Nazis in France,
15:27at a cost of $2.6 billion in today's money.
15:33But the technical challenges are immense.
15:37So these buildings were built over 100 metres long and 100 metres wide and 18 metres high.
15:43It's just a huge amount of mass which your foundation needs to resist.
15:50To erect the pens as quickly as possible, the Nazis decide to build them on dry land.
15:55But there's a problem.
15:57Excavation of the foundations reveals that the soil is too unstable to take the weight of these massive structures.
16:04Engineers, I think, were quite worried about the building actually settling down and sinking into the ground.
16:09So they built the structure on pile foundations.
16:14Basically long steel beams or poles inserted vertically, pounded vertically into the ground,
16:20and that gives you the ability to resist sinking of the building.
16:28With the foundations in place, boats, trucks and railway wagons
16:33bring 152 million kilograms of raw material into Lorient every month to feed the construction.
16:42On top of that, thousands of workers from all over the Nazi empire are drafted into Lorient to build the pens.
16:53Alongside them, a handful of skilled French engineers occupy senior positions.
16:59One of them, the deputy director of naval construction, is called Jacques Stoscoff.
17:06I need the estimates from the steel chart for the tonnage.
17:12Stoscoff was one of a number of highly skilled French engineers who worked here at the base.
17:17His main role was at the arsenal, the storage facility for torpedoes,
17:21which was a little way away from the pens themselves.
17:24I want you to provide this before the end of the month.
17:30So is that all, sir?
17:32No, excuse me.
17:34What made Stoscoff different was that he was from Alsace, the border region between France and Germany.
17:40That meant that he spoke excellent German.
17:43That made him particularly useful to the German hierarchy.
17:46When you have the figures, let me have your reports.
17:55Gradually, his responsibilities increased, and he supervised French workers all across the base.
18:01He wasn't particularly well-liked by his compatriots, partly because he was a rather serious character,
18:06but also because of his close associations with the Germans.
18:10But men like Stoscoff were essential to the Germans in keeping the construction and the operation of this base on track.
18:19As construction progresses, U-boats continue to sail from Lorient.
18:25It rapidly becomes the most important base in France, known as the Base of Aces,
18:31as all the U-boat top guns dock here.
18:35Men like Gunther Prien.
18:39Having already sunk 27 Allied ships, at the end of February 1941, he sails out of Lorient on a new mission.
19:01Keep it steady!
19:03Hunting a convoy of 37 ships, Prien and three other U-boats attack.
19:09Fire! Fire!
19:21But they're spotted by Allied destroyers and forced to dive for safety.
19:26It's coming straight at us! Dive! 90 meters!
19:33Dive! Dive! Dive!
19:36Prien's crew rush to the front of the U-boat to speed the subs' dive.
19:50Remaining totally silent is vital, as the destroyer's sonar listens for any noise from the U-boats.
20:03Hush!
20:10Once detected, the Allied escorts unleash hundreds of depth charges.
20:34No survivors?
20:39Prien's death hits Dönitz hard.
20:44It confirms how vulnerable his subs are, and how vital it is to complete the new pens.
20:52As construction steps up, so does the influence of Frenchman Jacques Stoskopf.
20:58He was a rather serious character.
21:00And his close associations with the Germans meant that he developed a reputation as a collaborator.
21:09On one occasion, he was responsible for organising 250 Frenchmen to be sent to Germany to work.
21:17As the train left the station, some people in the crowd were heard to shout,
21:21Death to Stoskopf!
21:30Death to Stoskopf!
21:33Meanwhile, the submarine bunkers K1 and K2 continue rising at a phenomenal rate.
21:40By December 20th, 1941, after just ten months' work, the pens are completed.
21:46And not a moment too soon.
21:48Just nine days earlier, Hitler had declared war on the United States.
21:53Despite facing two of the most powerful navies on earth,
21:57Nazi U-boats continue causing havoc in the Atlantic,
22:01sinking 27 ships in December alone.
22:06The U-boats are using up their stocks of torpedoes almost as fast as they can replenish them.
22:13But Dönitz's new U-boat bunkers are ready,
22:16and the entrance towers over the harbour at Lorient.
22:19K1 and K2 were unique in that there was only one access point from the water.
22:26Once they'd entered the dock,
22:29the gates would have been closed and the water gradually pumped out.
22:34Beneath the water is a cradle sitting on a ten-degree ramp.
22:39The submarine settles in the cradle and is winched up the ramp towards the dock facilities.
22:46U-boats are then pulled out of the safety of K1
22:49and onto a transporter unit between the two pens.
22:57This is a post-war French submarine, but the unit itself is the original piece.
23:01It's absolutely enormous.
23:05It had 32 wheels.
23:07It was the largest in the world.
23:09It had 32 wheels running along various rails,
23:12left to right and parallel with the pens themselves.
23:16That meant that the U-boat could be shunted into position
23:19next to whichever dock was ready to receive it.
23:24This system is unique.
23:26There's nothing like it anywhere along the Atlantic coastline.
23:29But it's also quite vulnerable.
23:31The U-boats are exposed out in the open air,
23:34Just one bomb strike here would render the entire system completely useless.
23:38And any U-boats that were being repaired wouldn't be able to get back out to sea.
23:42And, of course, they wouldn't be able to receive any new U-boats coming in through K1.
23:46The whole process takes around 90 minutes
23:49before the U-boats are safely under cover again.
23:53It's hard to describe just how enormous a space it is.
23:57This is what it looks like.
23:59It's a bit like a submarine in the ocean.
24:01It's a submarine.
24:03It's got a lot of cargo.
24:05It's got a lot of equipment.
24:07It's got a lot of batteries.
24:09And, of course, it's a lot of space.
24:11It's a lot of space.
24:13And it's a lot of space.
24:15It's a lot of space.
24:17It's hard to describe just how enormous a space this is and there were 13 of these all
24:25around the base in K1 and K2.
24:32It's so tall that an overhead crane could come over the submarine and remove the periscope
24:37completely.
24:38Pulling the entire 5-metre long periscope out of the submarine is just one of a number
24:44of repairs and checks that must be done.
24:47In fact, almost half of all the repairs and refits that happened to U-boats on the French
24:52Atlantic coast were done here in Lorient.
24:55That's what made it so special and so critical to the German U-boat campaign.
25:01Lorient's transformation from fishing port to deadly U-boat base enables Admiral Dönitz
25:07to hit 500 Allied ships in 1941 and force Britain to the brink of defeat.
25:13The U-boat war was the only thing that frightened Churchill, as he later admitted in his memoirs,
25:18about the war, the possibility of Britain's resources being cut off at sea.
25:23And it prompted him to focus the attention of the British Armed Forces and the Allies
25:27in general on winning the battle of the Atlantic.
25:33He directed them to hunt the U-boats at sea and to strike them at their bases.
25:43Built to shelter the Nazi U-boat fleet from Allied bombs, Lorient is now British Prime
25:53Minister Winston Churchill's number one target.
26:01This leads the Nazi planners to fear that their concrete giants may not be tough enough
26:05to survive.
26:07So at Karimantou, the roof was roughly three and a half meters thick.
26:11I mean, that's even thicker than the walls of Fort Knox.
26:16Originally, I think they wanted something thicker than three and a half meters, but
26:21they were concerned at this location that the foundation wasn't strong enough to support
26:25it.
26:26And so the Lorient base has to evolve again.
26:30The Nazis begin building an even bigger pen, which they hope will be truly impregnable.
26:36The K3.
26:40The new pen requires stronger foundations.
26:44Built behind giant dams which hold back the sea, they are forged from the bedrock itself.
26:52So the building work was much more difficult.
26:55There was considerably more construction done on Karimantou than on Karimantou 1 and Karimantou
27:012.
27:02It wasn't a perfect structure, as in certain parts the walls holding up the upper levels
27:07were up to 20 feet thick at the base, and the Germans could reinforce the upper level
27:12without destabilizing the building.
27:17Construction of K3 moves at breathtaking speed, with concrete poured 24 hours a day to get
27:22the pens built before an Allied attack comes.
27:28Despite Churchill's decree, the skies remain empty.
27:34We are fortunate the British do not attack these pens from the air while they are under
27:39construction.
27:45Dönitz believes Lorient is safe.
27:53What he doesn't know is that the French resistance have a man on the inside.
28:00Jacques Stoskopf.
28:02Jacques Stoskopf was known as an active collaborator.
28:09But nothing could have been further from the truth.
28:12His increasing access to the U-boat pens meant that he could keep a daily watch over the
28:16comings and goings here.
28:18He had a formidable memory, almost photographic.
28:22And by identifying the emblems on the sides of the U-boats, he was able to build up a
28:26detailed picture of the daily operations here.
28:30He would meet in secret with the contact from the French resistance, and pass on his information.
28:38Commandant Lem deported at 0500 hours on the 20th of February.
28:44U-106, Captain Rush.
28:47We're sighting it twice to make sure you have the details correct.
28:51U-103, Captain Schultz, arrived 2300 hours on the 24th of February.
29:00Three boats sunk.
29:06Again.
29:09Commandant Lem.
29:10He provides information on Wolfpack numbers and U-boat successes.
29:21Stoskopf also passes on plans and technical information that might be used to defeat the
29:26U-boats.
29:28This information would then be sent back to the British.
29:31And in the Battle of the Atlantic, information could be a crucial weapon.
29:40And in his secret battle against Dönitz's fleet, Stoskopf is risking everything.
29:57Through 1942, construction on the K3 bunker is consuming vast amounts of German resources.
30:05Hundreds of concrete mixers working day and night exhaust the available supply of sand.
30:11So it's taken from the beaches.
30:14Notably sand for cement and reinforced concrete.
30:18This came from the seaside, the coast.
30:20So it contains salt and if you mix it with cement, it doesn't bond well.
30:25And as there was an extremely high iron content, this would accelerate the corrosion, making
30:30the building more fragile.
30:32So the Germans had all the sand washed in fresh water in these giant sieves.
30:43In a bid to build an indestructible submarine base, this attention to detail is crucial.
30:51Towards the end of 1942, the vast K3 bunker nears completion.
30:55It's a concrete fortress, with huge steel gates guarding the entrance to docks that
31:01can be drained of water in just a few hours.
31:10But the roof covering the complex is the Nazi engineers' greatest achievement.
31:15So at Karabin 3, they weren't even satisfied with a three and a half metre thick roof.
31:20They wanted something thicker.
31:23And so they revised the design and what they came up with was, on top of the roof, build
31:29two precast beams in a triangular form to create an air gap of roughly half a metre.
31:36So on top of the air gap, they built another three and a half metre roof.
31:40So in total, you would end up with a roof of seven to seven and a half metres thickness.
31:47That's the thickness of two double-decker buses or of three stories almost of solid
31:53concrete just above the structure beneath.
31:59Dönitz has asked for an unsmashable lair.
32:02And it seems that the German engineers have delivered.
32:06In January 1943, the dams built to keep the sea out during construction are blown up and
32:16the K3 pens finally open.
32:21But it's much more than just a military installation.
32:23For thousands of people, it becomes home.
32:28When you imagine that there were 15,000 people here, you realise that not only did the Germans
32:33need to bring in everything that the U-boats needed, but they also needed to bring in everything
32:38that the people needed too.
32:39So this base was full of power stations, water purification units, storage facilities, extra
32:47railway tracks had to be built to bring in all of these supplies.
32:51And as the base developed, as its importance developed, more and more needed to be built
32:55here to sustain the workforce.
32:59This isn't so much a workshop as a small town.
33:06In the abandoned offices, storerooms and accommodation, some of which haven't changed since the war,
33:13you can still see flashes of the people who lived and worked here.
33:21All over the place, there are relics from the previous life of this room.
33:27Look, you can still make out some German writing here.
33:37After the war, the French would have taken down any Nazi insignia, painting over any
33:42German writing.
33:44You can still make out some of the original details.
33:50You can still see up here some of the original paintwork.
33:55At the time, they would have tried to make it as homely and as comfortable as possible.
34:01It's quite eerie, it's quite spooky.
34:07This is obviously a bed frame.
34:10This would have been someone's bedroom as well as their workplace.
34:15And then just through this window that's been boarded up is the pen itself and all the work
34:19going on.
34:20So there's no escaping it.
34:22This would have been a 24-hour-a-day operation.
34:28And it needed to be because Lorient was absolutely vital to the U-boat campaign.
34:33They needed to get the work done quickly and efficiently and get the U-boats out back
34:37into the ocean.
34:38With servicing work going on round the clock, these chambers would have been hives of activity.
34:45But for the returning crews, Lorient offers more than just a base.
34:54It's a release.
34:58Since the start of the war, 155 U-boats have been lost, nearly half of them in the second
35:04part of 1942.
35:08But their sacrifices that year also result in a dramatic increase in Allied losses.
35:14Over 1,600 ships are sent to the bottom by these submariners.
35:21Amongst their number is U-954's new second watch officer, Peter Dernitz.
35:28Just 21 years old, the Admiral's son is part of a growing number of inexperienced U-boat
35:36crews brought in to replace those killed at sea.
35:42But Churchill is still determined to stop the U-boats putting to sea at all.
35:48British and American bombers launch raid after raid against the base.
36:00Contact the base. I want a detailed report of any damage as soon as possible.
36:07Yes, sir.
36:13Amidst the devastation, the U-boat pens still stand.
36:18Dernitz's determination to provide his fleet with the best possible protection has paid
36:22off.
36:24But the Allies are still determined to crack the pens, and so they construct the biggest
36:28bomb yet made.
36:32The Tallboy.
36:32The Tallboy is a special bomb, a bomb that weighed over five tons, carrying two tons
36:38of explosives.
36:39It was dropped at 6,000 meters, so by the time it reached the target, it would be traveling
36:44at the speed of sound in the hope that it would penetrate the reinforced roofing of
36:49the U-boat pens.
36:51Eleven of these gigantic bombs are dropped on the city.
36:57Only one makes a direct hit on the pens, but with the Tallboy, one might be enough.
37:05In early 1943, the indestructible U-boat pens face their toughest ever test.
37:16Two and a half billion kilograms of thick reinforced concrete suffer a direct hit from
37:22an earthquake bomb designed to smash it.
37:30Well, this is absolutely incredible.
37:35This is where the Tallboy actually hit the bunker, but you can still see clearly where
37:42the original line of the roof would have been, and remember, that's three and a half meters
37:47of concrete that the bomb has penetrated straight through, literally obliterated, but you can
37:54also see the gap between the roofs, and then through that, you can quite clearly see the
37:58second layer, and what's most impressive is that there's barely a scratch on that layer
38:03of roof.
38:05From underneath, for the people working in the bunker itself, it must have sounded quite
38:09horrendous, but crucially, they would have sustained no damage at all.
38:18Whichever way you look at it, this is an absolutely incredible feat of defensive construction.
38:25The base has proved indestructible, and Dönitz continues to personally direct the U-boat
38:30battles out at sea.
38:32Here are my orders. The Meuse Group are to proceed northwest at high speed.
38:41Understood? Good.
38:46The Allies realize that they will never defeat the U-boats in their indestructible base at
38:50Lorient, so they develop technology to go after them at sea instead, and it's Dönitz's
38:57own communications that give the Allies the chance they need.
39:03Allied intelligence were able to penetrate German high-level communications. Admiral
39:08Dönitz had to stay in constant communications with his U-boats to coordinate their attacks,
39:14and the U-boats had to communicate with each other. That gave the Allies a way of locating
39:18them and ultimately destroying them.
39:21The hunters are about to become the hunted. The Allies develop equipment to detect U-boat
39:28radio signals, and they break Dönitz's secret Enigma code, enabling them to read his messages
39:34to the U-boats.
39:38Oblivious to this, on May 17, 1943, Dönitz orders a wolf pack to attack a convoy of 37
39:45ships sailing from Canada.
39:48Which boats are closest to this sector?
39:51U-544 and U-954, Admiral.
39:58Order them to close immediately.
40:03U-boat 954 is carrying Dönitz's son, Peter. The 21-year-old officer is eager to experience
40:10his first major action.
40:12Order, sir. A nice fat convoy heading for us. At least 14 heavy ships and a light screen
40:20of destroyers.
40:25From cracked Enigma messages, the British convoy commander knows exactly where the U-boats
40:30will be. The escort destroyers and bombers from Iceland spring their own trap.
40:37My God! Alarm! Aircraft attacking on the port bow!
41:15U-954, carrying Dönitz's son, is lost with all hands.
41:28The Allies' technological advantage proves the decisive blow in the battle for the Atlantic.
41:35Forty-three U-boats are sunk in 1943.
41:39My U-boat men, you have fought like lions. We have been driven into a tight corner from
41:53which it is no longer possible to continue the war.
42:01Just five days after the loss of his son, Dönitz orders all his crews back to base
42:08and scales down operations.
42:11Dönitz's campaign had failed. The balance in the battle of the Atlantic had shifted
42:15dramatically in favour of the Allies. The Allies had defeated the U-boat threat at sea
42:22and in 1944-45, Hitler's armies were being pushed back on all fronts. Defeat was now
42:29inevitable.
42:31But at Lorient, one man won't live to see the end of the war.
42:36In 1944, Jacques Stoskopf vanished. He wasn't particularly missed here in Lorient. He still
42:43had a reputation as a collaborator. But in fact, his resistance cell had been broken
42:50and his name given up. He was arrested by the Gestapo and then taken to a concentration
42:58camp, where he was interrogated, tortured and finally executed with a single shot.
43:10In 1945, Hitler and his empire falls to the Allies.
43:18The war was over. Even as Berlin was falling, the indestructible U-boat pens proved to be
43:28just that, indestructible.
43:31They were one of the last bastions of Nazi resistance, only surrendering to the Allies
43:36two days after the end of the war. Today, the pens still stand. And in a few years,
43:44these overwhelming structures are now dedicated to a man who sought to destroy the U-boat
43:49fleet.
43:50In 1946, the naval base at Lorient was renamed after Jacques Stoskopf.