Nova (1974–…): Season 42, Episode 9 - Nazi Attack on America - full transcript

Following the attack on Pearl Harbor German seizes the opportunity to attack cargo ships along the United State East coast while the United States is unprepared. This program describes the scope of the German assault as a backdrop...

Are you wondering how healthy the food you are eating is? Check it -
January 1942

America is just weeks
into World War II

when the European fight
comes to our shores

Hitler's U-boats waste no time
going on the attack

They brought the war to us

in a way that caught us
by surprise

The attacks are devastating

Thousands of lives lost,

more ships sunk
than at Pearl Harbor,

and Nazi spies secretly
delivered to American soil

They kicked our asses,

and yet we were getting
no payback

A lot of Americans
have forgotten

how close the war came
to our shores

and how close it was
to our homes

Now renowned explorer
Robert Ballard and his team

are returning
to this forgotten battlefield

with the latest technology

Okay team, 100 meters

Here, we're able
to get a picture

that shows you
what it would like

if you could take the water away

Their work will help rewrite
this chapter of World War II

and bring closure to
a 73-year-old mystery:

who sank German U-boat U-166?

How close did the Nazis come
to victory in the Atlantic?

Right now, on this NOVA/
National Geographic special

The Gulf of Mexico, 120 miles
off the coast of New Orleans

These peaceful waters
were once the setting

for a violent, little-known
chapter of World War II

Deep below the surface
lie the remnants

of a devastating Nazi attack
on America: Operation Drumbeat

Just after the US entered
World War II,

Hitler's submarines,
the deadly U-boats,

struck hard and fast
up and down the East Coast

They hunted down and sank
the vulnerable cargo ships

that were critical
to the Allied war effort

And they took the war further,
extending their assault

all the way
into the Gulf of Mexico

Now, explorer Robert Ballard
and his crew

prepare to investigate
this battlefield

To reach the sea floor,

they'll use high-tech remotely
operated vehicles... ROVs

The beauty of the ROVs,

these vehicles can stay down
for days and days and days

Square up on the target
and drive over to it

The ROVs descend one mile
beneath the surface,

where the casualties
of the Nazi assault still rest

A World War II-era cargo ship,
the Alcoa Puritan

In 1942, she hauled aluminum ore

vital to America's
wartime factories

Her scars are still vivid

That's a hole,
that's a shell hole

So if you could stop laterally
and go in and frame that

These are bent inward

Yeah, you can tell it went in


Joining Ballard is wreck diver
Richie Kohler

He's spent decades studying
and diving on sunken U-boats

This wreck is a snapshot

of when the U-boats
first came to America

This is when the U-boats
were not afraid of us

We hadn't got our act together

Not far from the Alcoa,

an oil tanker, the SS Gulf Penn,

90,000 barrels of oil
still trapped inside

These are in some ways
ticking time bombs

in the sense that the
hull will rupture

and you'll have oil come out

Could you look at that wreckage?

Could you look at the wreckage
before you go too far?

But Ballard and Kohler's
ultimate goal

is a pair of shipwrecks
resting not far away,

one the hunter, the other hunted

This is the SS Robert E. Lee,
the victim

In 1942,
407 souls walked these decks

On board the Robert E. Lee
was not only passengers,

but there were actually

from previous
German U-Boat sinkings

that occurred out
in the Atlantic Ocean

Square on the gun
a little better

A three-inch deck gun
had been added for protection

against the U-boat threat

This gun never went into play

They never had a target

He's locked up,
he's in a stored position

The attack came
with almost no warning

You could almost imagine them
standing along the side

looking at what they thought
was a porpoise

and then it makes a turn
and comes into them

It's actually a torpedo

Today, the fatal wound
inflicted by the German torpedo

is hidden beneath layers of silt
on the ocean floor

It's amazing that most
of the damage is not visible

Now, we're looking
at a ghost ship

I mean, it's obvious
that it was abandoned

We can see where the four
lifeboat davits were swung out

Within five minutes,

these people were in the water
fighting for their lives

Just over one mile away,
the attacker:

German U-boat U-166

Missing for 59 years,

her rusting hull was spotted
in May 2001

during survey work for a new
underwater pipeline

But how did U-166 sink?

Who was responsible?

And why is she lying so close
to her victim?

The official record offers
little clue

For decades, the circumstances
of this U-boat's sinking

have been mired in controversy

In 1942,
a young destroyer captain,

commander Herbert Claudius,
claimed credit for the kill

But the official report said
Claudius botched the attack

It was one man's word
against the US Navy

in a case obscured
by the fog of war

Ballard and his team
believe their technology,

building on the earlier
survey work,

can finally put the question
to rest

It isn't until fairly recently

that this submarine's been found

I'm gonna use my technology,

and see if an injustice was done
that needs to be corrected

It's a story that began three
years before U-166 was sunk,

before America
had even entered the war,

when Great Britain found itself
facing off against Nazi Germany

in one of the most pivotal
conflicts of World War II:

the Battle of the Atlantic

Lasting from the first day
of the war to the very end,

the fighting
would ultimately claim

nearly 6,000 Allied
and German ships

and span 5,000 miles of ocean

What was at stake was simply
Allied survival in World War II

Now at this stage of the war,

England was standing alone
against the rest of Europe,

which had been conquered
and brought under Nazi tyranny

If the British were defeated,
the war would be all but lost

There was no way that the Allies

were going to be able
to invade Normandy

from Hoboken, New Jersey

It just wouldn't have worked

You needed a launch pad;
the launch pad was England

But as an island nation,
Britain was vulnerable

Its survival depended on
supplies imported from abroad:

raw materials, food, weapons

Roughly one million tons
of cargo a year,

crossing the Atlantic

By 1941, the Nazis were close
to cutting off that flow

The key to their success
was the Unterseeboot...

German for "underwater boat"...

Known to the rest of the world
as the U-boat

The Nazis built nearly 1,200
of these deadly machines

They were meant
for one purpose only:

to attack

At either end of the U-boat

were tubes
for launching torpedoes...

23-foot-long underwater missiles

At its center, the conning tower

Below it, a maze of controls

for steering, diving,
and surfacing

Submerged, a U-boat's survival
depended on its pressure hull

Invisible from outside,

these structural ribs
and steel plate

were all that stood
between the crew

and thousands of tons
of seawater

Like today's hybrid cars,

U-boats relied on a combination
of internal combustion engines

and battery-powered
electric motors for propulsion

On the surface,
air-breathing diesels

could drive up to 18 knots,
roughly 20 miles an hour

the electric motors took over,

but the batteries
were a critical vulnerability

They typically lasted
less than 24 hours,

and the diesel engines

could only recharge them
on the surface

A U-boat is ultimately

a submersible rather
than a true submarine

It's not intended to operate
perpetually beneath the water

They have to be on the surface
several hours every day

in order to recharge
their batteries

And a U-boat on the surface
was a target

Despite this weakness,

the U-boats
were stunningly effective

The U-boat was a terrifying
weapon of war,

and it was especially terrifying
when it took on unarmed ships

that were carrying cargo

Commanding the German assault

was Kriegesmarine admiral
Karl Dönitz

During World War I
he commanded a German U-boat

That's where he learns
a lot of his lessons

He could be harsh at times,

but the U-boat men
considered him

a just leader,

and that's why they followed him
all through the war

With the US still neutral,

Dönitz focused his fleet
on the British ships

Wolfpacks, groups of U-boats

ranging from three
to more than 20 subs,

swarmed and overwhelmed
the British convoys

Dönitz directed the Wolfpacks
himself via long range radio

Admiral Dönitz was a very
hands-on type of manager

He wanted to know where
his U-boats were at all times

He required them to call in
on a daily basis

The Allies could hear
the transmissions,

but they couldn't
understand them

The Germans had a secret weapon:

the code machine known as Enigma

The Enigma machine itself

looks like
a very elaborate typewriter

that encodes and decrypts
the messages

as they're sent and received

The secret of the Enigma machine

was its constantly changing code

With every keystroke,

the code rotors that scrambled
the message shifted slightly,

generating a new code

No word would ever be encoded
the same way twice

Every day,
the sender and receiver

set the rotors to a position

listed in codebooks
each operator carried

The Allies had secretly copied
one of the machines,

but without knowing
the settings,

they had no hope
of deciphering the messages

By 1941,
the Enigma-equipped U-boats

were winning the Battle
of the Atlantic

England was being starved
into submission

In fact, British Prime Minister
Winston Churchill

would later say that
there was only one thing

that he feared
during World War II,

and it was the U-Boat

Then, a breakthrough

In May of 1941,
U-110 stopped reporting in

German command believed her sunk

In reality,
she had been captured

off the coast of Iceland

Her Enigma machine
and the code books

specifying the settings
were shipped back to London

British mathematician
Alan Turing

and a secret team of
codebreakers went to work

The British were able to break
the German naval ciphers

by the end of May,
beginning of June, 1941

That was critical
for saving British convoys

for the rest of 1941

The Germans had no idea

Mathematics, not munitions, had
bought the British crucial time

Until December 7, 1941,

when the Japanese bombed Pearl
Harbor and everything changed

With America officially at war,

US ships could now be targeted

Admiral Dönitz
seized the opportunity

to tilt the battle back
in Germany's favor

He knows that
right after Pearl Harbor,

if he sends U-Boats across

to attack the US Atlantic coast,

he knows he'll get a big payoff

because the United States
won't be ready

Dönitz believed his U-boats

could cut England's lifeline
of vital cargo

by striking at the source

Operation Drumbeat was born

But with his U-boats
stretched thin,

Dönitz had only a handful
of long-range boats,

known as Type IXs,
available to send to America

He assigns six Type IX U-boats,
and then one of them falls out,

so it's only initially five
Type IX U-boats

to operate off the US East Coast

The trip to America
took three weeks

British codebreakers
warned the US,

but in the wake of Pearl Harbor,
the Navy had other priorities

Neither the US Navy nor the
Army air forces was prepared

Not only did they not have
the airplanes

and the ships available,

but the ones
they did have available

did not have the sensors
or weapons

that could destroy a U-boat

Even basic protective measures
were ignored

You gotta remember,

all of Europe
is blacked out now,

and all the lights were on

There seems to be
no alerts whatsoever

Officials worried a blackout
could disrupt commerce

But no blackouts
meant cargo ships

were perfectly silhouetted
against the bright lights

They found, in effect,
U-boat Disneyland

It was wonderful

Horst von Schroeter
was watch officer on U-123

We closed the shore

within, say, two or three
nautical miles

We smelled the forest ashore,

and we saw the autos, the cars,
running on the shoreway

Erich Topp was commander
of U-552

and the third-most successful
U-boat commander of the war

It was a shooting of hares

It was because the Americans
at that time

had not developed counter-
measures against submarines,

and so we had
a very easy game there

It took one week,
as I remember, only

One week all the time, and we
sank, I think, about ten ships

In fact,
they return to their ports

in the Bay of Biscay
coast of France

empty, having fired
all of their torpedoes

By February 6,
barely three weeks

after the first U-boats arrived
in US waters,

they'd sunk 25 ships

Spurred on by the success,

Dönitz sent every U-boat he
could spare across the Atlantic,

including the newly built U-166,

the wreck Ballard
is closing in on

Onboard the Nautilus,
Ballard's team preps the ROVs

The primary unit,
named Hercules,

is equipped with several
high-definition cameras

Its sophisticated sonar will
locate and map the wreck site

This technology will offer
a view of the U-boat

with stunning clarity and detail

Hercules can dive
as deep as 2 5 miles,

putting U-166
well within its reach

But just like human divers,
it doesn't go alone

Hercules is tethered
to a second ROV named Argus

Physically linked
to the ship above,

Argus acts as a stabilizer
and light source for Hercules

It also sends video
up to the Nautilus

so the crew can watch
for potential hazards

Hercules is kept
on a short leash

to prevent its tether
from getting tangled

Operating the ROVs like this
is tricky

The ship's computers
must maintain its position

directly above the wreck

so the ROVs can safely
navigate the site

So computers
are driving the ship

Humans aren't driving
the ship right now,

it's being driven by computers

As we move the ship,
we're moving Argus

And Hercules's job
is to stay out on point

It will take over an hour

for the ROVs to reach
the wreck of U-166

By March of 1942,
Dönitz was sending

nearly half of his combat-ready
U-boats to attack America

The Germans had also regained
a crucial advantage,

a new Enigma machine

The German navy
increasingly suspects

that their cipher machine
has been compromised,

as indeed it has been

Dönitz upgraded the Enigma
machines on board his U-boats

with an additional rotor

Overnight, the new machine,
nicknamed Shark by the Allies,

made their codebreaking useless

From then on,
the Germans were well ahead

in terms of information

because the Allies
no longer could read

what the Germans were planning

For Dönitz and the U-boats,
the hunting was almost too good

They kept running
out of torpedoes and fuel

and had to travel 3,500 miles
back home to resupply

Until German engineers came up
with an inventive shortcut:

the Type XIV U-boat,
dubbed the Milk Cow

The Milk Cows
were not designed to fight

Instead of carrying
offensive weapons,

they just carried
extra fuel and provisions

and even extra torpedoes
for the U-boats

With 430 tons of fuel
and supplies,

the Milk Cows
were floating gas stations

And the Germans had an ideal
location to deploy them:

the Atlantic Gap

Aircraft based in North America,

aircraft based in Iceland
or Greenland

or in the United Kingdom,

their umbrella of coverage
left a gap right in the middle

That mid-Atlantic gap
was an area where U-boats knew

that they could operate
with impunity

because no Allied aircraft
could reach that gap

The Germans seemed to hold
every advantage

The U-boats were virtually

By April of 1942, three months
into Operation Drumbeat,

nearly 250 Allied ships had been
lost in American waters

Not a single U-boat
had been sunk

Happy times, they called it

In Germany,
"Die Glückliche Zeit"

There were more targets

than they could cope with

And the U-boat missions
were only becoming bolder

In June 1942,
the Nazis carried out

one of their most daring attacks
on America

Known as Operation Pastorius,
the program used U-boats

to land teams of Nazi spies
on American soil

The overall plan was that
German saboteurs and spies

would attack
vital railroad bridges,

aluminum plants that were making
the skin of the aircraft

that would ultimately drop bombs
on German cities

And the U-boat contribution
to this mission was vital

It couldn't have been done
without them

Two teams of spies were landed,
one on Long Island, New York,

the other near
Jacksonville, Florida

The spies dispersed
into the civilian population

and began their preparations

Dönitz and the U-boats

kept probing American defenses

They soon identified
an enticing new weak spot:

the shipping lanes
in the Gulf of Mexico

We had lapsed into the thinking

that everything's fine
in the Gulf of Mexico

because the enemy is not there

And so Dönitz sends them
into the Gulf of Mexico,

realizing that he'll get
yet another big payoff

with the Gulf of Mexico,

and oh, God,
what a payoff he got

In the month of May 1942,
he sank 41 ships

That's more than one ship a day

going down in flames
in the Gulf of Mexico

It was to this hunting ground
that U-166 would be assigned

for her first patrol in America

Home movies recorded by U-166's
captain, Hans-Gunther Kuhlmann,

show the young crew training
just weeks before the mission

On June 17, 1942, they left port
and set course for America

They would never be seen again

There's bottom

There you go

Aboard the Nautilus,

Bob Ballard is trying to
understand their final moments

What's it say?

Target bearing?

Target bearing is two thirty

Yeah, so it should show up
on sonar

They're coming down close enough

After reaching American waters
in July of 1942,

U-166 quickly sank three ships

and was looking for more
off the coast of Louisiana

On the afternoon of July 30,

another target appeared
in her sights:

the Robert E. Lee,
making its way to New Orleans

U-166 launched a single torpedo

The passenger ship
never fired a shot in return

Within minutes, it was sunk

But what U-166 didn't realize

was that the Robert E. Lee
was not alone

She had a naval escort ship,

Its captain was
a young naval officer,

Herbert Gordon Claudius

He was a farm boy from Nebraska,

and he, I guess, wanted
to get out of Nebraska

And then of course,

his first ship in the Navy
was the PC-566

PC-566 had been commissioned
only the month before

Claudius and his crew

were about to see combat
for the very first time

As soon as a German torpedo
struck Robert E. Lee,

Claudius swings the PC-566
into action

One of the men on deck of PC-566

observes a periscope
in the water

Claudius then turns the vessel
toward that periscope sighting

He's doing that in an attempt
to approach from its blind side

A U-boat's periscope
has a narrow field of view

With the U-166's lens pointed
at the sinking Robert E. Lee,

the German captain couldn't see
the Navy ship coming

He's in the fray right now

He's trying to kill this guy

He wants to sneak
right up on top of that guy

so he can't get away

He's bearing down on it
as fast as he can,

and when he's 120 yards away,
he sees the periscope retract

He's following the wake,

and directly
over the estimated position,

he's setting off a sequential
series of five depth charges

The depth charge
is an underwater bomb

and the Allies' primary weapon
against U-boats

The attacking ship
estimates the location

and depth of the U-boat,

then sets the charges
to detonate

when they hit that depth

Fire two

Fire two

Water pressure
triggers the explosion,

sending a shockwave
ripping through the ocean

The explosion isn't powerful
enough to blow up a U-boat

The idea is to simply
crack its pressure hull

then let thousands of tons
of seawater finish the job

But depth charges aren't
necessarily a death sentence

The shock wave is only dangerous
up close

If the U-boat can dive
out of range, she can escape

U-boat crews had a series of
carefully rehearsed procedures

for trying to elude
depth charges,

as shown in this actual
wartime footage

The bow planes were set
to maximum angle,

driving the boat deeper

The electric motors were set
to full power

Men who were not on duty
ran forward

Their weight helped point
the boat down

The emergency dive

was the most critical test
a U-boat crew could face

Seconds meant the difference
between life and death

Horst von Schroeter
was watch officer

on one of the first U-boats
in Drumbeat, U-123

From the order alarm,

it took 30 seconds
to disappear from the surface

and another 30 seconds
to be on a depth of 60 meters

30 seconds can be
a long time in war

Werner Hirschmann
was chief engineer on U-190

I would call anybody

who was not scared for his life
under those circumstance a liar,

because it is a scary experience

to hear a depth charge
dropping into the water

and then expect,
in about five or ten seconds,

an explosion to go off

There's nothing you can do

You can just sit there and wait,

and this period of lack
of activity is really unnerving

The crew of U-166 left no record
of their final moments

They didn't send a radio report
that day,

or even a distress signal

All that is known comes from
the report filed by Claudius

He dropped a second round
of depth charges

An oil slick spread
on the surface

So now the periscope's
no longer visible,

the depth charges have gone off,
there's no wake

You know, did he kill it?

And he sees an oil slick

You know, that's a very good
indication that he hit it

In his report,
Claudius was clear

It is my opinion that
the sub was sunk

or so mortally wounded that she
would never return to her base

I mean, this is the fog of war

But he is pretty confident that
that oil slick

is associated
with that submarine

They attack the submarine

They come back
and rescue the survivors,

the 400 people that are in the
water from the Robert E. Lee.

Claudius radioed for help,

knowing that his ship was
too small to rescue everyone

It's not that big a ship

It was so top heavy

that he actually had to unload
some of them back into lifeboats

so that his ship became stable

But then two other ships
came out

and between the three boats,

they took them back
to New Orleans

Claudius returned to port
with the survivors

Then, a shock

Instead of getting
a hero's welcome,

he was actually reprimanded

His entire attack is criticized

As a matter of fact,

he's removed from command
and then sent back to school

They didn't believe,
not for one minute,

that he had actually sunk
the U-166

Senior commanders
concluded that Claudius

made a series of basic errors

They said he was
in the wrong position

while escorting
the Robert E. Lee;

he approached the U-boat
the wrong way;

and crucially, he deployed
his depth charges too slowly

and at the wrong depths

They're all saying, "No way

"No way did he sink this sub

"The attack
was poorly conducted,

"and there is insufficient

to give higher assessment
than an F"

An F!

Says "F" right there


That's pretty humiliating

Gordon Claudius, Herbert's son,

was only two years old
at the time

He believes the review
of his father was unfair

It was not favorable

He didn't talk much about
well, his wartime activities

My sister,
she was older than I was

and more in a position to think
about things and ask questions,

and she said,
well, she asked him one time

and all he said was,
well, he attacked a submarine

and he saw an oil slick
and he saw debris

That was it

I think it not only got
to my father,

but I think it got
to the whole crew

After the war,
captured German records

revealed that U-166 was the only
U-boat lost in the Gulf

But the Navy concluded
that U-166 had been sunk

in an entirely different attack
that took place two days later

and 140 miles from where
commander Claudius gave chase

A U-boat is spotted

south of Houma, Louisiana,
running on the surface

And a US Coast Guard
patrol plane

attacks it with depth charges,

and then in the aftermath
of the attack

observes an oil slick
on the surface of the water

The Coast Guard air crew
was given credit for the kill,

and so official history
was written

Yet despite decades
of searching,

a wrecked U-boat was never found
at the location

where the Coast Guard plane
made its attack

It's not for a lack of trying

People are going out
on dive expeditions

thinking that they have
the exact spot

where U-166 went down,
but nobody finds it

Until 2001,
when marine archaelogists

from C&C Technologies made
a surprising discovery

during preparations
for an undersea pipeline

When we were looking at

the extra data
and we saw the bow section

And at that point we looked at
each other and we were like

All the pieces came together

And it turns out
it was the U-166

We knew in that moment

that Lt Commander Claudius
and the crew of PC-566

had sank U-166

Yet 13 years later,

the Navy record still denies
Claudius credit

So now we need
to set the record straight,

because this guy died without
recognition for what he did

Unless Bob Ballard and Richie
Kohler can find a way

to prove to the Navy that
Claudius was responsible,

the official record
will stand as is

A mile below,

Ballard's ROVs are closing in
on the wrecked U-boat

All right, showtime

Let's drop down there

There it is

Thar she blows

She is in incredible condition,

right where the previous survey
said she would be

The aft part of the submarine
looks like we could

just blow off the dust,
start the engines and go


250 feet long,
weighing 1,100 tons,

in 1942, U-166 was

a state-of-the-art
killing machine

Now she is a tomb

Oh, my gosh

That's a gun

So far, no damage is apparent

Back up a little

Frame it a little

Right there, okay

Though Richie Kohler
sees evidence

that the crew of U-166
knew they were in danger

There is a couple
of telltale signs

that this sub was
in a crash dive

or trying to get down real quick

Number one, the aerial,

the antenna that you see
that's bent,

that's a transmitting antenna

So it wasn't making

It's supposed to be retracted
when they're diving

So he was too busy to do that?

Everything stopped

We've got the 20 millimeter gun

that should have been locked in
position for underwater travel

It's swung out to port

The periscope never came
back down all the way

You can almost, you know,
see these men

are running to the forward end
of the submarine

trying to get the bow heavier,
trying to get it down,

because they knew
trouble was coming

And they didn't make it

They didn't make it

It does appear the sub
was running for its life

But so far, they see no sign

of the tell-tale fractures
in the hull

that two rounds of depth charges
should have produced

The wreck seems
surprisingly intact

And then, something strange

Now, that's not normal

Could you stop right there,
Will, and zoom in on that?

Ballard zooms in,
looking for the bow,

the front of the sub

It appears to be buried
in the sand, but it's not

It's completely gone

There's no way a depth charge

could have sheared off the bow
of U-166 like this

So what happened?

The missing bow holds
vital clues

We gotta go find the other piece

The ROVs move out
across the sand

For many meters, there's nothing

Then suddenly

It's the missing bow

And it's been reduced
to scrap metal

This is definitely not
a depth charge

If that was a depth charge,

we would not see
this thin lattice work

This would've been
totally blown away

Normally, a depth charge
just cracks the pressure hull

But this is no fracture;
it's an amputation

Most of the time,

we see concave indents
from depth charges

We don't see twisted
and torn metal

With this level of destruction,

it makes it difficult
to ascertain what caused what

It's a conundrum

The location supports Claudius's
claim that he sank this boat,

but the damage doesn't match
a normal depth charge attack

like the one Claudius made

To understand what happened,

the team needs to put the two
pieces of U-166 back together

We know that we've got this
up in the bow, separated,

and then we don't know how much

Well, you know,
we take the two pieces

and we see how much of it we see

Put them together
and you see what you're missing

But the visibility is too murky

to image the entire wreck
in one shot

We can't see very far underwater

I mean, if you're lucky
you can see 30, 40 feet

Fortunately, Ballard's ROVs
are equipped

for just such conditions

What we'll do now is

we've now outlined, and so
we need to bring Clara up

Is Clara in the ready?

So we can digitize
this whole thing

Clara Smart is the team's high
resolution mapping specialist

As she watches, the ROV
does a sweep of the wreck,

taking thousands
of close-up photographs

with its ultra-high
resolution cameras

The vehicle takes one image
every three seconds,

and what we're going to do is

we're going to combine
all these images to create


One very big, beautiful image

You can see it's marching along

Yep, and it's just matching
one picture to the next

The whole idea overall is
when we are on a site,

we have a flashlight
in a hay field

and you can't see anything,

but once we make these maps,

all of a sudden,
like all the lights came on

so we truly see exactly
what's down there

Clara will spend
the next several months

the thousands of close-ups

into a single giant wide shot,

called a photo mosaic,
that shows the entire wreck

Every rivet and crack will be
visible with unmatched clarity

Here, we're able
to get a picture

you can't get any other way,

a map that shows you
what it would look like

if you could take the water away

And that'll help tell us
what happened to the submarine

Back at the University of Rhode
Island, Clara gets to work

To start,
computers assemble the images

But they can only do so much

As you can see,
we've got some issues

In problem areas,

Clara will have to match
individual frames by eye

It's a laborious process

Ballard calls Richie Kohler

and historian Marty Morgan
to his lab

The mosaic of U-166 is complete

Thousands of photographs have
been seamlessly meshed together

But will the mosaic give
the team what they need?

We took about 2,000 images

with the ROV,

and that's been boiled down
to these two mosaics

So this is really CSI

We're talking
about 2,000 pictures

to give us one continuous image

of what the U-166 looks like now

Right, and it would be
as if you were flying over it

with an airplane and you saw
an aerial view

The key evidence lies

somewhere in the break
between the two pieces

That's where it all took place

The fact that this has been
completely blown off

And 100 meters away

And 100 meters away

You know, the question is,

was the depth charge
enough power

to literally tear off
the front of a pressure hull?

It's not really been seen before

In almost every instance

So you're led to believe

that there was another culprit
in the mix

When the two pieces of U-166
are slid back together,

they see that the break occurred

right at the forward
torpedo room

Interesting enough,

right here, where my finger is,

is exactly where the torpedo
tubes would have been loaded

You can see them clearly
in the blueprints

We know they're there

But something destroyed
the torpedo tubes

And there's how many
torpedoes here?

There could have been four

Four on the deck,
four spare reloads

Spare torpedoes
were stored on the floor

of the two torpedo rooms,
bow and stern

If the forward torpedoes
somehow exploded

while stored inside U-166,

that could explain the
incredible damage to her bow

If that is what happened,
it points to an unlikely

and catastrophic chain of events

As U-166
frantically dove to escape,

Commander Herbert Claudius
dropped his depth charges

So they were pretty shallow

Well, they were seen on the
surface with their periscope up

This is what has led me
to believe the possibility

of one of the five depth charges
that were distributed by PC-566

landed on the deck there

And it carried it with 'em

Marty Morgan believes
a depth charge landed

directly on top of U-166

As the sub dove to escape,

she carried the bomb down
to its explosion depth,

setting off a chain reaction

that detonated her own torpedoes

That would make sense because
clearly it was so instant,

he's just putting
his periscope down

His dive angle isn't that great

He probably wasn't even
30 feet deep

Right, so it very conceivably
landed on him, clunk,

and he carried the bomb

Carries it down with him

Hustling forward
to weigh down the bow,

the crew might have run right
into the exploding torpedo room

If you understand how the German
submarines would dive,

one of the things they would use
the crew for is ballast

They would tell the crew to run

run to the front!"

And that's exactly
where it happened

The team is convinced

While a depth charge
couldn't produce the damage

seen on U-166, it could have
detonated her torpedoes

Combined with the U-boat's

it makes a persuasive argument

Instead of being reprimanded
for his attack,

Commander Herbert Claudius
should have gotten a medal

Nice shot

Perfect shot, actually

Couldn't have done it better

But the team still faces
a huge hurdle:

convincing the US Navy

Ballard, a former
Navy commander himself,

puts their findings in writing

and forwards them to
the Chief of Naval Operations,

the most senior officer
in the Navy

73 years after the battle,

the Navy agrees
to review the case

Though it wasn't apparent
in 1942,

even as U-166
sank to the bottom,

Operation Drumbeat
was already drawing to a close

The sinking of 166

This is the first time we

in the Gulf of Mexico,
drew blood

Didn't mean that we had
taken the teeth away

from the U-boats

No, they were going
to continue to sink ships,

but now it was going
to cost them,

it was going to cost them dearly

Allied science and engineering

were finally beginning
to turn the tide

Improved radar and
high-frequency direction-finding

meant the U-boats
could be detected

whenever they surfaced,
even at night,

while mass production of
aircraft like the B-24 Liberator

meant the Atlantic Gap

was no longer a safe haven
for the Milk Cows

But the decisive stroke came
with the capture of U-559

in October of 1942

What they get out of U-559
enables Allied codebreakers

to regain that insight
into the new Enigma machine

with its fourth rotor

And by the end of December 1942

and certainly
by the spring of 1943,

the British and Americans

can now read German U-boat
signals in almost real time

The Enigma code
was cracked once again

The U-boats had lost nearly
all their advantages

Even the Nazi spies
of Operation Pastorius,

landed via U-boat
to sabotage American industry,

proved to be utter failures

All eight operatives
were captured within days,

and the Germans
canceled the program

Never again would U-boats
rule the seas

They had failed
in their stated goal:

cutting off the flow of supplies
from America to England

Yet they had come
dangerously close,

and the damage caused
by their attacks was immense

Hitler's U-boats sank 609 ships
in American-protected waters

Over three million tons of cargo
never made it to Britain,

and over 5,000 lives were lost

On the German side,

out of the 743 U-boats
lost in World War II,

only ten were sunk
in American waters

Of those, only one was sunk
in the Gulf of Mexico: U-166

But will the Navy give credit

to Commander Herbert Gordon

At the Navy History
and Heritage Command,

historians have analyzed
Ballard's evidence,

as well as reports
from the marine archaelogists

that first IDed U-166

The two teams are nearly
lockstep in their conclusions

It was Commander Claudius and
his naval escort ship PC-566

The Underwater
Archaeology Branch

here at Naval History
and Heritage Command

looked at the information

and confirmed that absolutely,
we believe that

PC-566 did successfully
attack and sink U-166

Whether it was skill,
whether it was luck

or a combination of both,
they were successful in the end

In 2014, 72 years
after the battle,

Admiral Jonathan Greenert,
chief of naval operations,

and Secretary of the Navy
Ray Mabus

award Commander Herbert Claudius
the Legion of Merit

Good afternoon, everybody,

and we're here to recognize
and actually to honor

Lieutenant Commander
Herbert G Claudius

This is really for me a story,
I think, of history obviously,

but also a story of explorers,
of shipmates,

of friends, of historians,
and I think relentlessness

to set the record straight

Gordon Claudius,

the only surviving child
of Herbert Claudius,

is here to accept the award
on his father's behalf

Now, 70 years later,
because of technology,

we now know that your father's
after-action report

was absolutely accurate

And I think this is
a good example of,

"It's never too late
to set the record straight,

it's never too late
to do the right thing"

So it's an honor
to be here today

to present your father

with the Legion of Merit
for valiant actions

during a very tough and very
dangerous combat situation

On behalf of your father

Thank you

I present this to you
with the V for Valor,

which means it happened
in combat

It sure did

This really brings closure
on a story that began

a month before I was born
73 years ago

So this is a wrap, a nice wrap

So long after the conflict,
World War II is fading history

Few remember the battles
Herbert Claudius

and other heroes once fought
so close to our shores,

but the sunken remains
are still there,

often nearer than we know,

enduring reminders
of just how close the Nazis came

to setting history
on a very different path