All language subtitles for Engineering.Evolved.S01E06.1080p.AMZN.WEB-DL.DDP5.1.H.264-BurCyg_track3_[eng]

(exciting music)

- [Narrator] Since the
invention of the wheel,

humans have pushed the
boundaries and possibilities

to go faster, higher, and
deeper than ever before.

The engineering evolution of
cars, ships, planes, trains,

submersibles and rockets has
been a monumental journey

of inspiration, innovation,
sometimes failure and success.

So how did we get
to where we are now

and where are we going next?

(exciting music)

They've been dubbed steel
monsters, war machines,

and apex predators of the deep.

- They're very stealthy
craft that can sneak up

on other vessels or on
cities around the world.

It really has a huge
advantage in naval warfare.

- [Narrator] For a good
chunk of modern history,

submarines have been primarily
used for national defense,

but in recent times,
submersibles have been

indispensable tools
for exploration

and laying down vital
underwater cables.

- Pipelines, electrical
cables, communication cables.

Our internet infrastructure
is on these cables

that go through the ocean.

- Using submersibles provides
a really safe opportunity

to do some sort of repair
work and maintenance

on crucial infrastructure.

- [Narrator] Submersibles
are venturing into the depths

to unlock the secrets of the
unknown and connect the world

in unprecedented ways.

However, their design
has changed very little.

- We're really relying
on the cylindrical shape

to provide the strength
to resist that pressure.

- [Narrator] Innovation
and new engineering

and technology could
spawn radically different

submarines of the future.

The deeper we go, the
more danger there is.

- The conditions are so
harsh that if you could

do it unmanned, it's much
better than risking humans.

- Unmanned vehicles are really
important to understand this

vast portion of our globe
that we haven't had access to.

- There's an entire
world under the sea,

different creatures,
different plant life,

a lot to discover.

It's almost like out of
a science fiction novel.

- [Narrator] In 2019,
Triton submarines,

deep submergence vehicle
DSV named, Limiting Factor,

achieve the deepest dive made

by any human crewed
submersible in history,

reaching a depth of 10,928
meters at the Challenger Deep,

in the West Pacific Ocean.

- This is a incredible
feat of engineering

and it's basically like
exploring a piece of space,

something that has been
otherwise untouchable

and unimaginable to
reach in human history.

- The DSV Limiting Factor went
down to almost 11,000 meters

and that was a an
amazing accomplishment

because for the first
time, we managed to win

against all those crushing
forces of the water.

- [Narrator] Triton
Submarines was commissioned

to engineer and construct
the Limiting Factor.

The project began with the
forging of its pressure hull

from titanium, which
was then pressure tested

to ocean depths, plus 20%.

- The pressures we're
dealing with at 10,000 meters

are immense.

If you look at where the
human is actually sitting,

it's a sphere. Spheres
are incredibly strong.

They're built to support uniform
pressures acting on a body.

- When we pay attention
to the Limiting Factor,

we find that at
least on the outside,

there seems to be some sort
of composite or plastic,

which is easily moldable
to particular shapes,

avoiding sharp corners or edges.

- In aerodynamics,
sharp corners are bad.

Fluids, airs of fluid,
waters of fluid,

of course, when these
things are acting on a body,

you want rounded surfaces,
they're easier to control

and they balance out
the amount of stresses

that are gonna happen
on that surface.

- [Narrator] Stress
concentrators refer
to multiple points

or features in a material where
localized stress increases,

allowing for pressure
to be released.

- Think of a cloth.

You can try to pull a
cloth apart with some force

and you might not
be able to do it.

Now, add a stress
concentrator to that cloth.

So now add a little
notch and pull it apart.

It's going to rip
right at that notch.

The cloth without the notch,
without the stress concentrator

was actually a stronger material

than the cloth with the notch.

- [Narrator] Normally for a
submersible to descend and rise,

they're fitted with ballast
tanks that are either filled

or emptied of water or air.

To safely descend to
the deepest depths

of the earth's oceans,
not one, but three

different ballast
devices were engineered

for the DSV Limiting Factor.

- And we want a system that
can withstand the deep depths.

So we want to avoid using
traditional ballast tanks

that we fill in empty with water

because when we get that deep,

they're just gonna
want to crush.

With this vessel, what they've
done is they've decided to

use a foam material.

- [Narrator] Syntactic
foam is a resin

mixed with hollow glass spheres.

This incredibly strong,
incredibly buoyant material

can be machined
to a precise shape

and gives the Limiting
Factor its buoyancy.

- This vessel also has
weights it releases,

so like a scuba diver, scuba
dive divers also carry weights

down with them, and this
helps them get passed

that surface buoyancy,
it helps them get down,

but when you get to
deeper and deeper depths,

you don't need that
weight anymore.

So this vessel can relieve
itself with some of that weight.

- [Narrator] This
variable ballast system

carries a maximum
weight of 100 kilograms

to control the speed of the dive

and to equalize its buoyancy
just above the sea floor,

weights are jettisoned in
five kilogram increments.

If any of the crew members
on board should become unable

to operate the craft
while submerged,

a single 100 kilogram
weight held in place

by magnets, is released.

Ensuring the Limiting Factor
finds its way to the surface,

no matter the circumstance.

- These are the designs
that are incorporated

into this vehicle so that
it can maintain buoyancy

which make it innovative
from other submarines

because it doesn't use the
traditional ballast tanks.

- [Narrator] Innovators have
been working for centuries

to solve the basic challenges
of operating a vessel

in the supreme environment
of the deep sea.

- Life support on a submarine
is a lot like being in space.

You have to bring the
entire supply of everything

to support humans with you.

You need a source of oxygen,
you need a source of air,

you need to get rid of CO2.

There are a lot of
things you have to do

to support human life.

- Naively, when we
think of submersibles,

we do just think going
down, but we also eventually

need to think of coming back up.

And so how do you
design propulsion

and how do you design vehicles
that take both into account

and do it safely?

- One of the biggest engineering
challenge of submarines

is dealing with the pressure.

We have to design these
submersible vessel structures

to withstand that pressure.

- A far cry from the designs
and engineering vessels

that we have today, early
submarines were not much more

than airtight barrels that
were designed to explore

just below the
surface of the water.

- [Narrator] The world's
first submarine was drafted

by William Bourne in 1578,
an English mathematician

and former Royal Navy gunner.

He designed an enclosed
craft made of wood

and bound in waterproof leather,

which could be
submerged and rowed

beneath the water surface.

An integral part of his
design, ballast tanks.

- Conventionally and
traditionally submersibles

tend to have ballast tanks.

The reason for these ballast
tanks is to allow the sinking

and the eventual floating of
these submersible devices.

- [Narrator] Though,
William Bournes design

never got past the drawing
stage, it paved the way

for the submarines
of the future.

- Controlling the dive for
the submarine is crucial.

It's quite literally life or
death for the crew inside.

If you go too
quickly up or down,

there are really terrible
effects on the body.

So this is a very important
element to control.

- So for example, scuba
divers can safely go down

to about 30 meters
without a lot of issues.

Once you start getting
below 30 meters,

if you're breathing normal air,

your body becomes
saturated nitrogen.

And then when you come
back to the surface,

that nitrogen can be
released from your blood,

produce bubbles and give
you decompression sickness,

the bends.

This has the potential to
cause life-threatening injuries

to your spinal cord
and other things.

So when we design submersibles,

we want to keep the
pressure in that submersible

pretty close to one atmosphere.

So an atmosphere is the
pressure that we experience

every day on earth from the
weight of the atmosphere

pushing down on us.

For every 10 meters we go down,

the pressure increases
by one atmosphere,

but all of a sudden we're
going down a thousand meters

where we have a hundred
atmospheres worth of pressure.

So now we have to maintain
the inside of that submersible

at the same pressure
as the surface,

but now we have a hundred
times the surface pressure

pushing in at the same time.

That's a huge
engineering consideration

to overcome in the design.

- The rate at which these
submersibles rise and fall

don't concern just people.

They also concern the actual
submersible vehicle itself.

Rising too quickly, that
can have detrimental effects

on the integrity of the vehicle.

And likewise, also sinking
too deep too quickly

could also cause some sort
of catastrophic damage.

And so there's a
very delicate balance

that needs to be struck.

- [Narrator] Triton Submarines
continue to break barriers

with the Limiting Factor.

Aboard this vessel, operators
and scientists perform

the deepest dives in the Red Sea

during a mind blowing
ocean expedition, in 2020.

Capable of diving
11,000 meters deep

with carrying capacity
for two people.

The Limiting Factor is ideal
for exploring the unknowns

of the ocean teams venture
down to this unique seabed

entering an underwater volcano.

And this isn't the only place.

In the Indian Ocean,
in 2019, Triton crews

discovered never
before seen species

at the deepest point
of the Java trench,

including the sea squirts
and the hadal snailfish.

- I think it's really important
to continue exploring.

There's a lot of
knowledge to be found

by looking at a
part of our earth

that we've never
really been to before.

I'm sure there's a wide range
of plant life and sea life

that we can examine
and learn a lot from,

but there's also a lot
of materials and minerals

that may not have even
been discovered yet.

- [Narrator] Braving the
deepest crevices of the ocean

requires precision engineering.

Hull design and
construction for submarines

is vastly different
from surface vessels

because you have a
whole new set of forces

you're dealing with.

- These submarines are like
perfectly sealed capsules

and underwater any
small damage to them

could be very catastrophic
for the people on board.

- The primary concern is
really the static pressure

that the material is subjected
to over long periods of time.

And of course wherever
there are seals,

so you've got the
hatch propeller shaft,

all those seals have to also
maintain their integrity

under the very high
pressures that these vessels

are subjected to.

- At these kind of
depths, if we get a crack

in our pressure vessel, we're
gonna get a jet of water

coming in and that
water jet is so powerful

it can literally
cut through steel.

As engineers, we use
water jets all the time

to cut through steel to
make complicated shapes.

The same thing's gonna
happen with a crack

in the pressure vessel.

It's literally gonna cut
through the occupant.

In historic submarines,
especially those which

used batteries, flooding
the battery compartment

with sea water was devastating.

When we passed DC current
through sea water,

we can produce chlorine
gas and chlorine gas

has been used as a chemical
weapon for many, many years.

So a gas that's
burning people's lungs

and very quickly killing them.

So it's really, really important
that that pressure vessel

be well sealed.

The second thing that
happens is all of a sudden

we subject that occupant
to the deep sea pressures.

Almost instantaneously
their lungs would collapse.

It would literally
crush the occupant.

- [Narrator] To fight off
this oppressive force,

submarines require
a specialized hull.

- So you can think of a
submarine as a protective layer

between you and a massive
amount of pressure

applied to it from the ocean.

And you've got internal
air pressure with oxygen

that people are
used to breathing,

pushing back a little bit.

If we over pressurize
the inside of the vessel,

it could explode.

And if we don't prevent
the exterior loads

from destroying the vessel,
then it can actually implode

and crush everything within.

- [Narrator] The
pressure inside The hull

is kept at a level
that is slightly higher

than the surrounding
water pressure,

which helps to prevent water
from entering the vessel.

- With modern submarines,
we want to try and make them

more damaged tolerant.

To that end, we have an
outer hull and an inner hull.

The inner hull is our
pressure containment.

And pressure containment is
very difficult in submarines.

If we even have a tiny
dent in that hull,

because of the
nature of buckling,

it will actually cause the
submarine to collapse and fail.

So to that end, we
add an outer hull,

and the outer hull is
kind of this added layer

of protection.

It's almost sacrificial.

So if we bump into something,
we dent enter this outer hull,

it's not consequential
and it kind of protects

that inner hull.

And then we can go back
in the port and repair

that if need be.

So, the new modern submarine
designs are more resilient

because of that.

- Construction of pressure
vessels is a technology

that is immensely complicated.

First of all, the ceiling of it,

the joining of it,
the welding of it,

making it into an
actual pressure vessel

means you have no air
leaks, it's air tight,

and that's not easy to make
an entire submarine airtight.

And you can imagine the
engineering challenges

of making something airtight
in that large scale,

has to be precise, it
has to be super airtight

and it has to be sealed off.

- So with all machines, there
are safety factors involved.

We don't calculate the
loads that we're gonna feel

on the exterior
of this submarine

and design something to
withstand only that exact load.

We tend to calculate the loads
and then assume that things

will go wrong and we
over-designed to eliminate

some of those future risks.

- [Narrator] A few years
before the DSV Limiting Factor,

another breakthrough
submersible would set the stage

for diving machines to
explore the deepest caverns

of the ocean.

James Cameron used the
filming of his blockbuster hit

"Titanic," as an opportunity
to explore the famous shipwreck

through several dives
using a fleet of submarines

priced at $3 million.

The $650 million payday
from his smash hit

went towards the development
of other underwater research

vessels to explore
areas of the deep,

the specially designed
Deepsea Challenger

brought James
Cameron to the bottom

of the Pacific Ocean's
Challenger Deep.

This low point in the Mariana's
trench had been reached

by humans only once before,
and Cameron was the first ever

to make a solo
dive to this spot.

Cameron spent three hours
collecting research samples

and taking photographs in this
extreme remote environment

before returning to the
surface in his submarine.

But the breakthrough in
some of the most incredible

innovations in submarine designs

was the result of military
action and demand.

On January 21st, 1954,
the Navy's first nuclear

powered submarine, the
USS Nautilus was launched.

The USS Nautilus
represented a revolution

in not only submarines but
maritime technology as a whole.

Its served as the
experimental platform

for the current fleets
of nuclear powered

military surface
ships, submarines,

and commercial shipping vessels.

- In 1954, the US
Nautilus is introduced.

This is the first
nuclear powered submarine

and nuclear power's
really a game changer.

Here we have an energy source
that doesn't require us

to go to the surface every
hour or two hours to get air.

It can essentially run for
an incredibly long period

of time, years without
needing to be refueled.

On top of that, because we
can generate electricity

underwater almost indefinitely,

we can take water
and electrolyze it
and produce oxygen.

So all of a sudden we can
have an infinite amount

of air underwater, we
have sufficient power

that we don't have to
get to the surface,

and really the only thing
limiting our time underwater

is how much food we
can bring with us.

So all of a sudden we have
this stealth submarine

that we've always wanted.

We can go all the way across
the Atlantic or Pacific oceans

sneak up on our enemy and
they really won't even know

we're there.

- [Narrator] The Nautilus
embodied the next generation

of submarines transitioning
from slow underwater vessels

to warships capable of
sustaining 20 to 25 knots

submerged for weeks on end.

- It's a revolutionary
not only because of

the nuclear actor, but
we start having these

hydrodynamic designs that
are relatively efficient.

That means we can really achieve

some decent speeds underwater.

So it's actually going faster
than most surface ships

can move.

So it really has a huge
advantage in naval warfare.

- [Narrator] Today all the
submarines in the US Navy

are powered by onboard
nuclear reactors.

In 2020, the US Navy started
working on the first submarine

of its most advanced
nuclear powered

ballistic missile
submarine class to date,

the Columbia class.

This class of submarines will
be the largest ever built

by the US - 170 meters
long with a displacement

of over 1900 metric tons.

The USS District of
Columbia will be longer

than the Washington
Monument is tall,

which is also 28 times the
length of a male killer whale.

The total cost to build
and maintain this behemoth

is estimated to be $15
billion and it will be crewed

by approximately
157 submariners.

Each Columbia class submarine
will contain a nuclear core

to provide power for its
entire 42 year service life,

eliminating the need for
mid service refueling.

The Navy's newest submarines
must also be the stealthiest.

The USS District of Columbia
will use an electric motor

to turn its propellers instead
of the louder steam turbine

systems used on earlier
nuclear powered submarines.

- There's a number of ways
in which you could reduce

noise generation.

So one is by changing the nature
of the engines themselves.

So moving towards nuclear
powered electric engines,

which are intrinsically quieter.

- [Narrator] And
nuclear power does more

than provide stealth.

It's also a much
greener energy source

than traditional diesel
powered submarines.

- Nuclear power has
understandably had
a bit of a bad rap

for some things.

When things go wrong, things
go catastrophically wrong.

But when things go right, it's
actually a very energy dense

form of energy creation,
which is very useful

and it's actually much cleaner

than a lot of
other alternatives.

- It has a very low
environmental impact

in terms of CO2 emissions, so
it's good for greenhouse gases

and global warming and it has
the right kind of power levels

that we need for submarines.

- [Narrator] Although
it's not all good news,

as spent nuclear fuel
is highly radioactive

and requires careful handling
and long-term storage

due to its potential hazards
and may take thousands

or even millions of years for
them to decay significantly.

- One of the things that we
need to be concerned about

when we're talking about
nuclear is how we store

the nuclear waste.

In Canada, for
example, where we store

a lot of our nuclear waste
is in the Canadian shield

where we've dug very
extremely deep caverns

where we store
these things so that

they can naturally decay.

- Nuclear power has a really
big advantage for submarines

in that you don't have
to refuel very often.

Nuclear power cells
have a very long life.

So once you are up and running,

you're able to stay down
under the surface of the water

for a much longer time.

To simplify how a nuclear
reactor works on a submarine,

the nuclear reactions
create a lot of heat.

That heat is then
harnessed to create steam,

and then the steam is
used to make propulsion.

- You throw a neutron at an
atom, then when it splits,

it breaks down into
its component parts,

creating more neutrons, and
then that hits other atoms

and then creates more neutrons.

And so this is a cascade effect.

And so those neutrons
are usually in a uranium

or plutonium system.

And the reason why
we use those is

because they pack the
most amount of energy.

- [Narrator] Plutonium is
chosen for military uses

because it can release a
significant amount of energy

making it more powerful.

However, it has a
relatively short half-life,

meaning it decays
relatively quickly

losing its potency over time.

- While uranium is
more sustained, but
it packs less punch,

which is why we have
them for civilian use.

- [Narrator] The first test
reactor started up in the US

in 1953 paving the
way for the fleet

of nuclear submarines to come.

- We think of nuclear
reactors as being

these large
structures that we see

as we drive down the highway,

but there's no reason
why they have to be.

You can scale them down
to quite small sizes.

So there's a lot of
interest currently

in what are called
small nuclear reactors

that can be used by
local communities,

either to generate power
or by certain industries.

For example, a large steel
plant could be powered

by a small nuclear reactor.

If you reduce the size
of these even more,

then you can now think about
putting them onto vehicles,

of various kinds where
you can create power

and you have a power source
which is very compact

and lasts a long time and
can be built in a small way

that is self-contained
and quite safe.

- [Narrator] Another
key to submarine safety

is ensuring the crew has ample
oxygen to breathe on board.

In order to remove excess CO2

from a submarine's atmosphere,

crew members must use a
process called CO2 scrubbing.

This chemical process
uses sodium hydroxide

and calcium hydroxide or soda
lime inside onboard scrubbers.

When these chemicals react,
the soda lime traps the CO2,

removing it from the air.

- So it's a question of
maintaining the oxygen level

and removing the
toxic chemicals,

particularly carbon
dioxide from the atmosphere

to maintain quality of
life and life itself,

whether it's submarines
or spacecraft,

the same issues supply.

- [Narrator] Unraveling
the critical components

of a sub design so
it can safely operate

in the depths of the
ocean, took centuries

of trial and error and
testing in shallower waters.

The first practical submarine
was built by Dutch engineer

Cornelius Drebbel
while he was working

for the English Royal Navy.

Invented in 1620, this
submarine was a rowboat

covered with greased
leather, powered by rowers,

pulling on oars that protruded
through leather seals

in the hull.

- This first attempt
at underwater mobility

was only able to go down about
five meters in the Thames.

Like many forms of
transportation here,

we're seeing a
reliance on human power

that's been eventually
far surpassed

by more current and
advanced technologies.

- [Narrator] Drebbel initially
created this submarine

with the goal of
underwater exploration

while working under special
order for King James I,

the submarine was successfully
tested several times,

reportedly once with the
king himself on board.

However, despite
its functionality,

the sub never gained the
interest of the Royal Navy.

Today, the British
Royal Navy boasts

some of the world's
most advanced submarines
in their fleet.

The five astute class subs
are advanced, nuclear powered

attack submarines on the
cutting edge of technology,

the most advanced subs ever
operated by the Royal Navy.

They're armed with long-range
Tomahawk, land missiles

and Spearfish heavy
weighted torpedoes.

Throughout their 25
year service period,

the nuclear reactors
powering the astute class

will never need to be refueled.

Weighing in at 7,800
tons and 97 meters long

the astute class are a
force to be reckoned with.

Serving as the Royal Navy's
attack dogs for decades to come.

Submarines first emerged
in military operations

during World War I.

Several countries began using
submarines on a large scale

to attack civilian shipping and
occasionally enemy warships.

This created the need for
anti-submarine warfare

or ASW and began a
hide finder competition

between submarines
and ASW forces.

- There's huge downfalls
with these early submarines

for having to
surface all the time.

It basically means that
they can easily be spotted.

So if there's another
vessel in the area,

they're immediately gonna
be spotted, identified,

and then they can't dive again.

And because they're
not a large ship,

they don't have
surface armaments,

they're kind of a sitting
duck once they get spotted.

So we really want a vessel
that can stay down a long time

because they really
don't have capabilities

to defend themselves.

- [Narrator] Early ASW
mostly relied on the use

of static defenses
like underwater mines
or chain-link nets

to prevent the movement
of subs into secure areas.

Torpedo nets were
also hung from ships

as an anti-sub defense
to block torpedoes

from reaching their hulls.

Ships would also optimistically
try to damage submarines

by towing grappling hooks
connected to explosive charges

in the hopes of snagging a sub
or throwing charges overboard

in the direction of
a suspected vessel.

The war sparked heavy
research into higher tech

submarine detection.

One of the most common
ways to detect submarines

is using sonar technology.

- The first sonar like system
was invented by Louis Nixon,

in 1906.

- [Narrator] A naval architect
Nixon was using the system

to detect icebergs under the
water to help ships navigate.

- Thanks to the
development of sonar,

we were finally able to
actually see what was around us,

whether it be land
masses or any other kind

of object underwater and
especially enemy vessels.

- We don't necessarily
have to worry

that we're gonna be seen
in a submarine underwater,

visual cues are limited
when you're so far down

in the depths of the ocean.

But sound travels pretty far.

And so generally, if
people wanna detect us

while underwater, they're
going to be listening

for our position.

And so if we want to stay quiet,

we have to make sure that
we don't emit any noise

that can be picked
up by detectors

that are listening
for a position.

- [Narrator] Traditionally,
there are two types of sonar,

active and passive.

- Active sonar is based on
sending the mechanical wave

and waiting for its
reflection 'cause the speed

of this wave is known.

Therefore, we can
calculate a distance.

And passive sonar is a
technology which is based

on active listening, monitoring
the sounds under the water.

So when there is a
submarine, it has an engine

and that generates a
specific frequency,

which is very different
from the other sounds

that are naturally there.

- Your ability to pick up
a signal really depends

on the strength of that signal.

So you can have a very
powerful detector,

but then it'll also
pick up a lot of noise.

So you have to have the ability
to filter out all that noise

to ensure that the information
coming at the detector

is in fact a submarine
and not a power plant

operating on ground nearby.

- It's exactly the
same technology that
is used with mothers

to be able to take images
of an unborn infant.

So you can see what's
going on and detect

if there's any problems.

- [Narrator] In response
to the creation of sonar

came hydrodynamic
improvements to the hull

and the propeller.

- One of the things that
happens when you're moving

underwater at high
speeds is you can create

cavitation bubbles.

Basically, if you
go fast enough,

will create low pressure
pockets around discontinuities

in the hull, and when those
bubbles of water vapor form

and then collapse, it
makes a lot of sound.

The same thing happens
for propellers, as
a propeller turns,

if it's not well designed, it
produces cavitation bubbles

and those are easy to hear.

So we start designing submarines
that are designed so that

they're hydrodynamic.

They don't produce these
cavitation bubbles.

We have a huge amount of
technology going into designing

propellers so that they don't
produce cavitation bubbles.

- [Narrator] The
German design 212CD

and the British
Dreadnought class

ballistic missile
submarine have outer hulls

designed to deflect
incoming active sonar.

They also incorporate
traditional passive
sonar stealth,

including complex
anechoic coatings outside

the pressure hull designed
to absorb or reduce

the reflection of sound waves
and electromagnetic waves.

- With the development
of sonar had to of course

come the opposite of sonar.

Being able to hide from
sonar was very important,

tactically speaking.

So we achieve this by
developing a series of materials

that help you to
not reflect sound.

- Metals are typically
quite reflective.

So if you have something
which is more compliant

on the surface that will
absorb an incoming wave

and not just reflect it back,

then you can help
to deaden the sound.

- By covering a submarine
in something like let's say

a soft rubber tile,
the profile might not

be completely invisible, but
it might look to your enemy

like maybe it's a whale
or maybe it's something

else underwater.

- Now researchers are trying
to combine kind of bubble wraps

into tiles so the wave
wouldn't reflect at all.

- Any kind of gas
is much more squishy

than would be any kind of solid.

So if you can embed gas
bubbles into a polymer surface,

it will be more sound deadening.

It's not that different than
the kind of sound insulation

that you might have
in a concert hall.

You're using both
material and airspace

to be able to produce
sound deadening.

- [Narrator] Not only have
engineers use sound deadening

materials on submarines,
new submarine hull designs

include angles to deflect
sound in interesting ways.

- The hull shape is designed
in a bit of a different way

so that it doesn't reflect
sound back to the source

of the sonar emitter.

It actually deflects it away.

So this would help you hide
or change the sonar profile

that the enemy would
be seeing of your ship.

- The sound wave comes
off one of these angles,

but it doesn't
reflect completely.

You actually get
multiple waves emanating,

allowing this submersible to
be slightly less detectable.

- We start providing
sound insulating materials

to the hulls of our
vessels so that they become

even more stealthy.

So again, there's this arms
race between how good sonar is

and how silent we
can make our vessels.

- [Narrator] These novel
sound absorbing materials

also reduce the amount
of acoustic pollution

emitted by a submarine, which
not only maximizes stealth,

it's better for marine life.

- Acoustic pollution is
noise artificially created

where it disturbs the
natural environment.

If you have artificial
sources of sound

and they're terribly
prevalent in places

where whales are migrating,
then that can cause,

disorientation and
so it's important

to do what we can
to mitigate that.

- The North Atlantic,
the whale is dead or gone

because of the cargo ships
in the Labrador corridor,

going up and down from
West Indies to Canada.

So we might have to think about
new ways of moving things.

Maybe submarines would help
because if you're underwater

with the full sensor capability,
you can avoid whales,

you can avoid fishes,

you can avoid things
you want to avoid.

I feel it might be a
safer for marine lives

to have us travel in
submarines rather than ships.

- [Narrator] Without the
evolution of sonar technology,

the incredible unmanned
submarines of today
could not exist.

Innovative companies
are looking to disrupt

traditional methods of planning

for underwater infrastructure.

Ocean Infinity, a
pioneer of large scale

marine robotic operation
is assembling a fleet

of autonomous underwater
vehicles to perform

oceanic research, including
mapping the sea floor

and environmental monitoring.

This up and coming
company is at the vanguard

of unmanned underwater
vessel development.

UUVs deploying the
world's largest fleet

of marine robotics in 2017.

3 years on and their
engineers began constructing

the groundbreaking Armada
fleet featuring robotic ships

measuring up to 78 meters,
outfitted with high tech sensors

and cameras, their UUVs and
remotely operated vehicles,

ROVs collect data beneath
the waves and send it

to the technicians at the
remote control center on land,

allowing critical
decisions to be made

about undersea development
without putting any human lives

at risk.

- We have pipelines,
electrical cables,

communication cables, our
internet infrastructure

is literally based on these
cables that go through

the ocean, and every so often
they're in need of repairs.

So we need to figure
out a way to repair them

rather quickly, if you
wanna stay connected.

- So when we think about human
infrastructure underwater,

a lot of that is
around oil and gas.

These have fixed lifespans,
they have damage that can occur.

They need to be inspected.

And sending humans down to
those depths is difficult.

We actually use saturation
divers currently,

and saturation diving
is really unbelievable.

You take humans and you
put them in a chamber

and compress the air
in the chamber down

so that they match the
pressure of the sea floor

and then they can work.

But unfortunately,
because of the nature

of saturation diving, those
divers actually have to spend

days or even a week or
longer decompressing.

Saturation diving
is very dangerous,

and we really don't
want to put humans

into this environment.

So when we look at repairing
underwater pipelines,

we want autonomous technology.

We want vessels that
can go down there

and do the assessment
so engineers can
sit on the surface,

watch on screens, rather
than have physical people

in this hostile environment.

Autonomous inspections,
autonomous vehicles

to do welding and repair
to underwater pipelines

is really, really
important technology.

- [Narrator]
Development of the first

autonomous underwater
vehicles began in the 1960s

and accelerated rapidly
into the seventies,

eighties, and nineties
as humans became

more and more enthralled
with deep sea exploration.

- It's incredible that
life exists in these deep,

dark places.

And what sustains
it are the things

that we normally associate
with life like oxygen,

light don't exist down there.

- [Narrator] However, the
mysteries of the deep sea

are slowly being revealed.

Originally built in 1986,
the National Oceanic

and Atmospheric Administration's
Aquarius Reef Base

located off the coast
of Florida in the USA

is the only undersea
laboratory in the world.

Anchored at 18 meters
deep, the habitat itself

has just over 37 square meters
of living in laboratory space

and two-way stations
holding pockets of air.

It allows scientists and
researchers to live and work

underwater for extended
periods and undersea explorers

can top up their air
tanks during a dive.

The Aquarius system
has two other elements,

a life support buoy
at the surface,

and a base plate that
secures the habitat

to the ocean floor.

All elements must be
in good working order

to continue welcoming visitors.

- It allows for a
lot of new research,

a lot of new understanding
of deep sea biology,

and a lot better
understanding of our world,

which is mostly water.

We understand very
little about our oceans.

In fact, we now know
more about space

than we do about
our deep oceans.

- [Narrator] Not only
is Aquarius ideal

for underwater research,
it also trains astronauts.

NASA's extreme environment
mission operations program

sends astronauts into the
ocean where they can encounter

the same challenges
they would face in space

and must troubleshoot obstacles
in an extreme environment.

- Well, there's a lot
of parallels between
space exploration

and underwater exploration.

In both cases, you have to
carry all of the necessities

of life with you when you go.

It's a very constrained
environment that has all sorts

of human factor implications
in terms of how people adapt

to spending long periods of
time under those environments.

- [Narrator] Today's
underwater habitats

and high tech submarines
wouldn't be possible

without the post-World War
II submarine revolution.

A decade of
incredible innovation,

which began when German U-boats
were captured by the allies

at the end of World War II.

- In a 10 year period
from 1945 to 1955,

submarines were
really transformed.

They went from being
ships that could submerge

for brief periods of time
to true underwater vessels

that could remain underwater
for weeks at a time

and easily navigate.

- [Narrator] The U-boat was
by far the most sophisticated

submarine of its time,
decimating its enemies,

during World War I.

The Germans leveled up their
designs for World War II,

where commanders
operated their subs

with extreme discipline,
employing stealthy tactics

to avoid detection by sonar
used by the allied forces.

- When we look back at
the history of submarines,

when we're talking
about World War II,

the German engineering's
really amazing to see.

- [Narrator] Showcasing
streamlined hulls
that reduced drag

and made them more
efficient underwater

and snorkels for diesel engines,

a retractable mast that
allowed the diesel engines

to run while the submarine
remained underwater.

The highly advanced U-boats
inspired new thinking

in every major Navy.

- We sort of got a little bit
better at building engines,

but that came with its own
issues because an engine needs

air and it produces exhaust.

And so we needed to have
this constant supply of air

with oxygen, and then we needed
to then exhaust that exhaust

from that engine to make
sure that those toxic fumes

weren't gonna be kept inside.

So we at first started off
by simply having a snorkel.

- Snorkel, it has to be one way.

It has release air. You
don't need water coming in.

It has to have a one way valve,

and it has to have a storage
container that is pressurized.

So you need to make sure that
you have a one-way vacuum

suction pressure, and
then you need to exhaust

what you're breathing out
because that's adding volume

of air in your submarine
that you need to exhaust

at the same time.

So that's another
challenge as to how

you're gonna exhaust this.

- Basically, if you stay a
few meters below the surface,

the snorkel allows you to
run almost indefinitely

with a very small
visible footprint above
the water surface.

This makes it much harder
to detect the submarine,

and you can run long
distances, slightly submerged.

So this is kind of
that step between

having to come back to
the surface all the time

and between nuclear submarines,
which consensually stay down

for, you know, weeks
or months at a time.

- [Narrator] It wasn't until
nuclear power eliminated

the need for air supply that
submarines had the ability

to stay underwater indefinitely.

- So when we realized
that the power we needed

on a submarine was
electric in nature,

we decided to just generate
the electricity directly

and skip the whole diesel part.

The natural progression
was that we needed

to have a power plant
in the submarine.

And the only power plant I can
think of that doesn't require

oxygen and it doesn't
produce toxic fumes

is a nuclear power plant.

- [Narrator] But
staying submerged is
not without its risks.

In August of 2000, the
Russian submarine Kursk

sank to the bottom
of the barren sea,

located up the northern
coast of Norway and Russia,

it's considered one of the
worst submarine disasters

of all time.

The entire 118 man crew
perished during a naval exercise

after two undersea explosions
destroyed the vessel.

Rescue efforts were
greatly hindered

by frigid water conditions and
poor underwater visibility.

- Not only did this accident
have a serious human toll,

but it also raised
significant questions

about this in
response to submarine

and anti-submarine warfare.

- [Narrator] To ensure
that such a tragedy

never happens again, in 2013,

NATO developed an
international hub to combat

submarine emergencies.

A direct response to
the Kursk disaster.

Teams from 41 nations
bond together to train

for worst case scenarios
so that the rescues

can be performed
successfully in all types

of sea conditions.

These training exercises
are also an opportunity

to test out the latest
submarine technology

from every country
involved, including

many submarine rescue vehicles

and specially designed
rescue chambers.

As submarine rescue
methods continue to evolve,

so do submarines themselves.

Made in the United
Arab Emirates,

the Kronos armored submarine
could be a game changer

for the future of underwater
exploration and operations.

Inspired by manta
rays and spacecraft,

researchers and designers
fuse these ideas together

to create this eye-catching
diving machine.

Its folding wings allow
for ease of transportation

to the water and its
hydrodynamic design

delivers high performance
and impressive efficiency

above and below the ocean waves.

Up to 10 passengers can
climb aboard comfortably

and travel across the water at
up to 80 kilometers per hour

and 50 kilometers per
hour when fully submerged,

its innovative, Hull design
reduces fuel consumption,

increases maximum speed, and
provides exceptional stability.

With a working
depth of 100 meters

and a maximum critical
depth of 250 meters,

the agile Kronos can be
used for commercial, rescue

and combat operations.

Equipped with a
diesel generator,

electrical engine,
and a water jet

air compressor and torpedoes,

This submarine is
ready for anything.

And thanks to its
dual sources of power,

the Kronos can run for up
to 54 hours in hybrid mode.

Before sub-sea propulsion
systems had advanced for longer

and faster operations under
water, submarine hulls

were tailored mostly
for use at the surface.

- While the submarine
hull has remained

relatively static over time,

every now and then we see a
re-imagining of this design.

- [Narrator] The
teardrop hull shape,

which was designed to
favor submerged operations

was used in the early stages
of submarine development.

But in the early 19 hundreds,
outer hulls resembled a ship

making them most
effective at the surface.

During World War II, as
submarine technology advanced,

hull designs reverted back
to the teardrop shape again

to reduce drag and
noise underwater.

Since the early 19 hundreds,

underwater noise
interfering with hearing

has been a problem.

During World War II, scientists
studied background noise

and invented acoustic minds
devices that would explode

when triggered by
passing ship sounds.

However, they needed to
know how loud the noise was

to set these devices correctly,

so they only went off
when a ship was around.

This need led to better
systems for measuring

underwater noise.

For instance, the
passive acoustic
monitoring, PAM systems,

consist of strategically
placed hydrophones

that listen for specific
acoustic signatures

to monitor and identify various
underwater sound sources,

including ship traffic,
marine mammals,

and seismic activities.

Although the first
submarine used in combat

came centuries earlier,
and as they had no engines,

they were pretty
quiet but impractical.

- When you look back in
say 1775 at the Turtle,

it's really one of the first
examples of a submarine

being used for
military applications.

This was designed to allow
the operator to attach bombs

essentially to the
hulls of British ships

during the blockade of New
York during the US Revolution,

but has a lot of
design concerns.

It's really a one man vehicle.

This occupant has to
operate a propeller by hand,

try to control where
this vessel's going,

try to control the
buoyancy, try to get close

to another ship's
hull and attach a bomb

and do this all at the
same time without sinking

and without staying
at the surface.

So it's too much
that's going on.

There's too much for the
occupant really to be able

to control this vessel well,

but has all the real equipment
of a modern submarine.

It has a propeller, it can move,
it has directional control,

it has buoyancy control,
and it has an objective.

It's actually doing something
so you can start to see

the engineering evolve.

- [Narrator] But even for
the world's most advanced

submarines, navigating
the depths of the ocean

is a constant battle.

- You're basically blind.

Anybody who's tried to scuba
dive or swim in a muddy bay,

you can't see anything.

You can't see your fingertips.

Certainly you can't
see far enough

if you were driving a submarine
not to bump into something.

So with submarines, we really
need some type of system

that allows us to
see our environment

when we can't really
use visual sensors

or even visual
observation directly.

- [Narrator] When
on the surface,

GPS can accurately determine
latitude and longitude.

But this system doesn't
work when the submarine

is submerged.

Submarines are equipped with
an inertial navigation system

INS, which measures
the boat's motion

and constantly updates
their position.

These systems were initially
developed for rockets,

but by the 1960s,
inertial navigation became

a critical core technology for
all US military submarines,

strategic bombers, and
ballistic missiles.

Because it does not
rely on radio signals,

the INS allows
submarines to navigate

while remaining hidden
beneath the surface.

Measurements provided by
accelerometers and gyroscopes

track the position and
orientation of the submarine

relative to a known
starting point,

orientation and velocity.

As technology evolved,
mechanical gyroscopes

were replaced by fiber
optic gyroscopes,

which provided the advantage
of having no moving parts.

As we navigate under
the water surface,

we are seeing the potential
that the oceans could provide us

with the green energy
we desperately need

to stop climate change.

The Ocean Infinity
teams regularly deploy

their robotic fleet to
the bottom of the sea

to support underwater
green energy initiatives.

Marine energy generated
from ocean waves,

currents, tides, and
temperature changes

has the potential to
be the world's largest

renewable energy resource.

But one of its biggest
obstacles is the limited number

of suitable sub-sea locations.

An issue that Ocean
Infinity is aiming to solve.

As their autonomous
submarines continue exploring

and mapping the sea floor,
more potential locations

for marine energy
initiatives can be revealed.

Green power sources for the
submarines of the future

are also evolving.

- A lot of the countries
that tend to have

nuclear submarines, they
tend to have very large

military budgets, and
so nuclear reactors

or nuclear energy
sometimes require

billions of not just research,

but also in capital
money to produce.

And they should not go unnoticed
that many nuclear reactors,

at least for civilian use,
have always gone over budget.

- So while installing a
nuclear reactor in a submarine

did technically unlock
the ability to explore

the oceans indefinitely,
it's not always the most

financially feasible solution.

And we need to think
of more practical ways

to get the autonomous drones
floating around and exploring.

- So when we look at historic
battery powered submarines,

we were really limited
our choice of batteries

in the early part
of the 20th century,

really, lead acid was
the technology of choice

and lead acid batteries
are very heavy.

They don't hold a lot of charge.

They don't have a lot of
capacity to allow the submarine

to go great distances.

With the advent of modern
lithium ion batteries,

lithium iron
phosphate batteries,

these batteries
are much lighter.

Lithium's a very light element.

They have very high
charge to weight ratios,

so their density is low,
but they can still hold

a huge amount of
electrical charge.

And this provides a
great opportunity for
submarines, again.

We can now build batteries
that will allow us

to power submarines for
relatively long periods

of time underwater.

So when we're looking at short
range military operations

or research and
scientific vessels,

all of a sudden we now have
a technology that allows us

to do it at much lower cost
than using a nuclear reactor.

So we will see lithium batteries
become part of submarines

going forward.

- [Narrator] As we
look to the future,

the new designs and innovation
in deep submergence vehicles

should mean we will
be able to go deeper

and for longer than ever before.

- The DSV Limiting Factor
broke through this glass floor

and allowed us to realize that
we can go to those depths.

And once we learned that
something is possible,

we become pretty creative
and find ways to use

that possibility to
explore and to do things

we previously didn't
know were possible.

- If we think about
extraterrestrial life,

we think we have to find planets
that look like the earth.

Well, life exists in
these deep dark places

and I don't think
we really understand

what it is that sustains
life in the deep oceans.

And that would be fascinating
to know more about.

- I'm really excited
for future submarines

because we really need to
explore mankind's last frontier,

and that's the deep oceans.

We really don't know a
lot about the deep oceans

and the future vehicles are
gonna allow us to get there.

- Places we've never even
thought of exploring before

and do precision work at scales

we've never considered before,

and allow us to expand the
ability to both understand

the ocean and to utilize
the ocean in ways

we haven't even thought of.

(exciting music)