Original subtitles

Today on "Impossible Engineering"...

The littoral combat ships, the U.S. Navy's

fastest combat vessels.

If you're a pirate or you're a drug runner

and you see that ship coming towards ya,

it's time to shut down your engines

and put up your hands.

To create a vessel in a class all its own.

She's basically one of a kind as far as warships goes.

I am sailing a ship that's unprecedented.

Engineers had to turn to the pioneering

innovations of the past.

Here we go.

Yes!

If these engines were to cut out,

this boat would be in serious trouble.

Oh, ho, ho! This is really incredible.

What an amazing airplane.

That made the impossible possible.

... Captions by vitac... www.Vitac.Com

captions paid for by discovery communications

the U.S. Navy has the largest sea force on the planet.

Throughout its over 240-year history,

its ships have carried out operations

in the deep blue waters of the world's oceans.

But today the Navy's assignments are evolving.

Gone are the days of open-water blue Navy battles.

Many of the places where we need to be as a Navy

are in coastal regions.

To combat problems such as piracy,

people-trafficking, and aid distribution,

the fleet must operate in shallow coastal waters,

known as the littorals.

To navigate waters close to the shore,

shipbuilding program manager captain Tom Anderson

had to construct a particular type of ship.

To operate effectively in the littorals...

We need a high-speed ship, and it's gotta be adaptable.

It's gotta be capable of doing multiple missions.

That's our challenge.

It's a challenge that chief engineer

lieutenant Damon Gilbert also had to overcome.

The ideal ship for this environment

would be a ship that's light,

a ship that has a very shallow draft,

and a ship that can handle itself

and move very quickly.

The solution...

The littoral combat ship class.

Made up of both the mono-hull freedom variant

and the trimaran independence variant,

this revolutionary class of ship

is at the vanguard of marine engineering.

This is gonna change the face of how we operate inside

those waters for years to come.

Built for speed,

both the freedom variant semi-plaining hull

and the independence variant's trimaran design

create ultra hydrodynamic efficiency.

Using lightweight aluminum, powered by an innovative

propulsion system,

each ship can travel over 45 miles per hour

in only 14 feet of water.

It's capable of being reconfigured

for multiple missions,

and it's able to deploy smaller boats.

A vast helicopter pad also extends the crew's reach.

But to produce a high-performance,

fast-moving fleet for shallow waters,

the ship's designers had to create

the most effective propulsion system.

The problem was standard propeller systems

significantly push the ship below the water line

and require much deeper waters.

If you want to chase down a ship

or you want to elude another vessel

to get out of danger, you want to be able

to maneuver as quickly as possible.

So how do you propel a ship this fast

in near swimming-pool depths?

This would not have been possible

without a breakthrough innovation from the past.

Humans have always needed to navigate

the world's shallow waterways.

Initially, we used arm power to paddle.

It was effective, but tiring.

Arg!

Out of the way!

Oh!

The vikings added a sail to conquer the coastlines.

This worked well, but... Huh?

Only when there was wind.

Gah! for Odin's sake!

With its small draft, the paddle steamer seemed to be the answer.

Well, I do declare... vikings!

But they had significant problems.

Oh, my!

In the 1940s, the introduction of air boats

brought high-speed travel to the everglades.

Whee!

Oh, no!

Whoa!

But a better system was needed.

Show-off!

In the Grand Canyon, mechanical engineer Dan Dickrell

is riding upstream on the Colorado river

to reveal one of history's great engineering achievements.

The beautiful noise you hear

right now is two 550-horsepower

8.3-liter engines pushing this 20-ton boat

up these crazy, crazy rapids.

If these engines were to cut out,

this boat would be in serious, serious trouble.

But the key to driving against the current

isn't in the engines.

It's due to a pioneering propulsion system.

Getting to places where others can't,

in extremely shallow water,

was born out of the imagination

of someone whose childhood desire

was to challenge the rapids

and go where no one else could.

To do this, New Zealand-born

inventor William Hamilton

needed to overcome the limitations

of standard motorboats.

Now, Hamilton had a problem with this.

Because the waters he wanted to to go on were too shallow.

Huge rocks would effectively wreck this crude propeller.

So Hamilton got rid of the propeller altogether.

In 1954, he commissioned a plywood boat

and attached a centrifugal pump to its engine,

creating a unique water-driven jet propulsion system.

How the Hamilton jet motor functions

is around the middle of the boat,

there's an intake that brings water in

from whatever body of water the vessel is navigating.

Hamilton's uses an impeller that's spinning very fast

to greatly accelerate this stream of water.

That water is highly turbulent and twisty.

And so the Hamilton passes the water through a series

of stator vanes, creating a uniform,

but high-velocity jet.

And in 1960, Hamilton tested his bold

water jet design at the Grand Canyon.

Hamilton vowed to be the first to take a vessel up

a 160 kilometer section of this

notoriously unnavigable Colorado river.

Now, it may look calm right here, but upriver,

the rapids are crazy.

He traveled against the current,

including the notorious Vulcan rapids in just nine days.

With his son John at the helm, Hamilton made history

and conquered the mighty river.

- Whoo! - almost 60 years later,

Hamilton's water jet's sheer power...

This acceleration is intense.

...And its ability to navigate shallow waters

with the added benefit

of mind-blowing maneuverability... Here we go!

Yes!

...Continues to open up new waters.

Whoo!

Thanks to this spectacular demonstration

of man versus rapids, this unique propulsion system

was embraced across the planet.

All right, let's go!

The ships' engineers have super-sized

Hamilton's water jet innovation

to create a revolutionary propulsion system,

capable of going 45 miles per hour in shallow waters.

The way that this ship achieves that speed is through the use

of two gas turbines and two diesel engines

that drive a propulsion train

that is propelled by water jets.

At Austal U.S.A.'s shipyard in mobile, Alabama,

the latest independence variant, u.S.S. Tulsa,

is having her jets inspected

and getting ready for launch.

When this ship is going full power,

there's roughly 24,000 gallons

per second passing through these four water jets,

which equates to the ability

to fill two Olympic-sized swimming pools

in less than a minute.

Not only do these massive jets

generate colossal power, they also act as a rudder.

Each water jet is capable of independently being steered,

which allows for a lot of flexibility and maneuverability.

Like Hamilton's water jet system,

water goes through four mighty impellers

and discharges at high velocity.

To steer, each jet's water flow is deflected

by a rotating nozzle,

enabling fast, agile maneuvers.

And to reverse, buckets pivot over the exit nozzles,

forcing the jet flow backwards.

Built into the hull, these massive ships

can operate in just 14 feet of water.

300 yards, turn.

Next course... 309.

Off the California coast,

commander Mark Stefanik is harnessing

this incredible power aboard the u.S.S. Montgomery.

The water jet system allows me to turn and maneuver the ship

with much more fidelity

and a great deal more responsiveness

than a traditional ship.

So by creating opposite forces on either side of the ship,

I can actually turn the ship almost on its own axis.

I can twist the ship in a perfect circle

because of the amount of control I have through the water jets.

The 100,000-horsepower propulsion moves this massive

ship over 45 miles per hour.

This is actually our full capacity right now.

You can tell there's quite a bit of turbulence back there.

And this vessel can practically stop on a dime.

I've pulled the ship to stern and go from full speed to zero.

It's a very, very smooth transition.

The entire ship just basically will stop in the water

within less than a minute.

By using water jet propulsion,

at 29 horsepower per ton,

compared to an aircraft carrier's

three horsepower per ton,

these combat ships are the most efficient

in the U.S. Navy.

It's basically like driving a jet ski.

This ship could actually maneuver sideways.

It could pivot itself by standing still.

That's something totally different

from any other warship out there.

This propulsion system is unrivaled.

But to be truly trailblazing,

the designers of these incredible ships

must overcome more hurdles

and turn to the innovations from the past.

To make the impossible possible.

The littoral combat ships.

These are the fastest and most agile combat ships

in the U.S. Navy.

And program manager, captain Tom Anderson,

believes they are unstoppable.

If you're a pirate or you're a drug runner

and you see that ship coming towards ya,

it's time to shut down your engines

and put up your hands.

But to operate fully armed and at full speed

without getting beached in shallow waters,

the ships must also be exceptionally light.

Every pound that goes into this ship is assessed,

because every pound that goes into this ship

is an increase in its draft

and a decrease in its speed.

And u.S.S. Freedom's chief engineer,

lieutenant Damon Gilbert,

had to strike the right balance.

The difficulty we find with the older ship designs

is the steel hull with the steel superstructure

makes the ship incredibly heavy.

The less weight we have equals a smaller draft.

Smaller draft equals a longer sustainability

without worrying about running aground,

without worrying about getting into situations

that we can't come back out of.

So how do you build a lightweight combat ship

without compromising on strength or size?

To resolve this conundrum,

the engineers looked to the past.

Humanity has always strived to find the perfect material

to stay afloat.

The Tamil fisherman of south Asia

only need a log under each arm.

Come here!

But when partially submerged, there was a catch.

Yow!

In the 9th century B.C.,

Assyrian soldiers lied on inflatable goat skins

to sneak up on the enemy.

Uh-oh.

Although they were lightweight...

The skins were vulnerable.

Oof! uh, hello.

And push.

For some, Clay was a cheap alternative.

A row of pots could buoy a raft easily.

Steady.

Look out!

Oh!

But avoiding the rocks wasn't always possible.

Oh, no!

Shipbuilders needed a more durable material.

Engineer Dan Dickrell is in Tulsa, Oklahoma,

unveiling a game-changing marvel

that sparked both a naval and aviation revolution.

Oh, wow! What a beautiful airplane.

Such an engineering icon.

This is the DC-3 flagship Detroit.

She was constructed 80 years ago,

the oldest flying DC-3 in the world.

Prior to this stunning machine,

most planes were made of wood.

Although lightweight, wood broke easily.

And in 1931, a Fokker F.10

lost an entire wing, crashing into the Kansas prairie,

killing all eight people on board.

As America reeled, wood-frame construction ceased,

and engineers had to turn to metal.

But this transition was only possible

because of a chance discovery

by German metallurgist Alfred Wilm.

Different metals also had different weights between them.

Here we have aluminum, and here we have steel.

For the same size, steel weighs about three times as much.

Because of aluminum's relative light weight,

it seems like the ideal material

to construct aircraft from.

The problem was 100 years ago, it just wasn't strong enough.

To strengthen it, Alfred Wilm experimented

with aluminum's chemical makeup.

He introduced different metals...

manganese, magnesium, and copper...

in different ratios to create an alloy.

He heated it to high temperatures then quenched it.

He repeated this process over and over again.

Unfortunately...

The aluminum was still very bendable.

Wilm gave up.

But when he returned to the lab a few days later,

something extraordinary had happened,

something so transformative

it would go on to revolutionize

military hardware across the planet.

It was very strong and quite literally changed

the face of aviation.

Making this impossible warship possible.

The littoral combat ships are the fastest

in the U.S. Navy.

But building attack vessels that are light enough

to navigate shallow waters

without compromising on speed

or size relies on a revolutionary discovery.

After experimenting with an aluminum alloy and giving up,

metallurgist Alfred Wilm discovered

something completely unexpected a few days later.

The aluminum... Had age-hardened.

It was much, much stronger.

Wilm's introduction of new metals chemically altered

the aluminum's soft crystals, and, over time,

new minute crystals had grown within

each one of the aluminum crystals,

reinforcing the overall structure.

Wilm called this new material duraluminium.

It was very strong,

and quite literally changed the face of aviation.

The new alloy became known as the winged metal,

and 80 years after its construction,

this iconic all-aluminum DC-3

is taking to the skies once more.

First launched in 1935, the lightweight DC-3s

became the world's first

commercially successful passenger planes.

Taking inspiration from aerospace,

L.c.s. freedom variant engineers have used high-grade aluminum

to create some of the lightest combat ships

of this size ever built.

The actual hull itself is steel, where the superstructure

or what we like to call sometimes the house

where people live and where all the facilities

are is actually comprised of aluminum,

thus saving literally tons of weight,

which has a direct effect on the draft.

Despite the freedom variant being 387 feet long

and 57 feet wide

and with a steel hull and aluminum superstructure,

the ship weights a comparatively light 4,000 tons

with a draft of only 14 feet.

But engineers on the independence variant

have gone one big step further.

So the "L" in L.C.S. Doesn't stand for little.

This ship is the largest all-aluminum vessel

operating on the seas today.

While constructing these trimaran mega-ships

in Austal U.S.A.'s Alabama shipyard,

at 415 feet long and a colossal 100 feet wide,

every pound counts.

Aluminum has great strength-to-weight ratio.

It's a third of the density of steel.

And for the volume of ship we're building here,

aluminum structure was the only way

for us to meet speed, range,

and draft requirements.

Taking Alfred Wilm's approach to the next level,

engineers have adjusted the aluminum recipe,

preparing the ship for salty waters.

Aluminum alloys that we used in construction of this ship

have good corrosive properties,

which means, unlike other Navy ships

where exposed steel needs to be painted,

this ship is not painted above the water line.

That saves us money and it also reduces the weight of the ship.

This weight reduction helped decrease the independence

variant's draft to a mere 14 feet.

And that enables us to go into waters and visit ports

that traditionally our Navy ships

have not been able to get into.

The designers of these revolutionary ships

are pushing the limits of marine engineering,

but to effectively carry out multiple missions,

they had to draw on more innovations from the past...

Here I am, aboard the ray gun.

This can manage speeds of up to 28 miles an hour.

...To make the impossible possible.

The littoral combat ship,

built to patrol the shallow coastal waters

called the littorals.

Program manager Tom Anderson has helped take

the U.S. Navy's fastest combat ships to a whole new level.

Operating in the shallows require high-speed ships

with shallow drafts.

The answer to those challenges is the littoral combat ship.

Made up of the mono-hulled freedom variant

and the trimaran independence variant,

the L.C.S.'S power-to-weight ratio

is more than double that of a typical destroyer,

and there's a reason the ships need such flexibility.

We need to have a ship that's capable of doing

multiple missions,

whether it's searching for submarines,

finding minefields and detonating those mines...

all these things are required for the future Navy.

But to be truly adaptable,

not only must these ships carry equipment

for multiple assignments,

they must also provide an effective platform

for air-based missions.

We're conducting helicopter operations.

Their are limitations as far as how much pitch

and roll a ship can have based on the weather and environments

in order to conduct those helicopter operations.

So how do you marry the performance of a speed boat

with the volume and stability of of an aircraft carrier?

To solve this seemingly impossible problem,

the U.S. Navy's designers had to seek

more inspiration from the past.

Off the south coast of England,

science communicator Kate Mulcahy

is investigating the origins of one of the fastest,

but most stable sailing vessels ever built.

Here I am, aboard the ray gun.

This is a 24-foot boat that can still manage

speeds of up to 28 miles an hour.

It has not one, but three hulls that are designed to cut

through the water to provide minimum resistance.

In 1946, Ukrainian engineer Victor Tchetchet

unveiled this trailblazing shape

at Marblehead race week in Massachusetts,

calling it a trimaran.

Although revolutionary in the yacht-racing world,

his design was inspired by pacific islanders

looking to improve the humble canoe.

You can still see why this design has endured

for so many years.

It's thin and long, which means

it moves easily through the water.

Also, it doesn't have a keel,

so it sits quite high in the water.

That means it's perfect for exploring shallow,

narrow waterways.

Despite all of this, it can only go as fast as I

or anyone can paddle in it,

which means its speed is limited.

Secondly, as you can see, it's not very stable.

So imagine this out on the open water

contending against waves.

So if I was to try and get in this...

If I try and... oh!

I don't even think... It would be possible...

Oh! ...without it capsizing.

So not ideal.

To island-hop across the open ocean,

the pacific islanders needed a new design.

And what they came up with was this.

This is the same long fin, central hull,

but with two outriggers lashed parallel on either side.

Now, when we were making this, we used plastic tubing,

but they would have been using just logs.

The addition of outriggers

instantly transformed this simple canoe.

So you can see this boat is much more stable.

It's practically impossible to capsize it.

The addition of the outriggers has increased the stability

and also increased the buoyancy.

That means that it sits higher up in the water

and means it's easier to explore the shallows.

And, finally, allowed me to add a sail,

so no more paddling for me.

With these clever additions, islanders

could access countless islands

throughout the pacific ocean.

Improving on the ideas of the islanders,

Tchetchet used the wide stable base to create

a gracious spread of sail.

He also streamlined the light, buoyant hulls so they cut

through the water and created minimal drag.

All of this is what makes the trimaran

as one of the fastest class

of sailing boat in the world today.

Employing a trimaran on a yacht is one thing,

but integrating this design onto a 4,000-ton

combat ship is quite another.

Trimarans are really important

when you're doing surface warfare type events.

To super-size this technology,

the Navy's engineers

had to make the impossible possible.

The littoral combat ships

are the U.S. Navy's fastest warships.

To achieve maritime speeds of 45 miles per hour,

engineers super-sized the principles

behind Tchetchet's racing yacht

to create the Navy's first

high-performance trimaran combat ship.

And at Austal U.S.A.'s shipyard in Alabama,

the u.S.S. Tulsa is receiving its finishing touches.

You see it has a very fine-tuned bow, designed to Pierce waves.

As we go further back, you see the hull widen.

And just here to the right, you can see the outrigger.

And, again, just like those canoes with the outriggers,

which give us that added stability,

we get high speed.

The stabilized central hull

with two outriggers moves the ship

displacement point upwards.

This reduces drag, allowing the ship

to reach speeds of over 45 miles per hour.

Additionally, the ship's vast width allows

for an 11,000-square-foot flight deck,

and the vessel can accommodate smaller boats below,

extending its capabilities across the world's oceans.

Trimarans are stabile platforms, and those are really important

when you're doing things like operating helicopters,

launching vehicles,

and conducting high-speed maneuvers

when you're doing surface warfare type events.

At sea level, this unique engineering is clear.

You get a really good perspective of just

how wide the ship is

and how that trimaran design provides for stability.

Commander Douglas Meagher is traveling

between its outriggers, also known as amas.

We've got over 200 feet worth of ama tunnel here.

Were as the ship transits through the water at high speed,

you get the very slender main body hull,

and you have this ama that's cutting the water

and maintaining the ship's stability

at 40-plus knots.

Any other ship in the Navy,

you're not gonna be underneath the main

hull form of the ship like this.

This is a one-of-a-kind design.

In its home port of San Diego, California,

both the freedom and independence

variants of these combat ships

are changing the face of nautical design.

The littoral combat ships allow us

to operate at high speeds in shallow water

with stability unmatched by

any other naval ship of this size.

And now commander Mark Stefanik

is setting off in the u.S.S. Montgomery

to patrol the California coast.

Well, he is definitely cutting the channel.

Let's give him the five short.

Five short.

But in these busy waters,

unforeseen hazards lurk everywhere.

Got a jet ski off the port side, 350 headed forward aft.

All right, I think we have a good shot

at taking them down our starboard side.

- 60 yards, right? - All right, steady as she goes.

Steady as she goes, 178.

So there's a number of sailboats that we had to maneuver for,

as well as some other small craft.

So that did add to the complexity of the ship

trying to get underway.

Crowded coastal waters are just the start.

Out in the open ocean, it's pretty easy to determine

what kind of traffic you're gonna deal with,

'cause there's very little of it.

When you're in a littoral environment,

you're operating in the vicinity

of very dense commercial traffic.

But in more hostile shallow waters,

determining friend from foe

can be the difference between life and death.

Nothing is more critical to the captain,

the decision to either engage

or not engage a potential adversary.

So how do you identify an enemy in a split second

in some of the world's busiest seas?

To do this, engineers had to turn to one of history's

most vital innovations...

to stand any chance of successfully defending

the country, the R.A.F. Needed a way of knowing

if an attack was imminent.

This was a huge problem.

...To make the impossible possible.

The littoral combat ships.

As the U.S. Navy's fastest war vessels,

these pioneering ships can patrol

the shallowest coastlines across the planet

with incredible dexterity.

But to determine friend from foe,

engineers had to turn to a revolutionary

breakthrough from the past.

Oh, ho ho!

Engineer Luke Bisby is flying in the British royal

air force's iconic biplane, the tiger moth.

He's here to reveal an ingenious secret

behind wartime engineering.

One amazing airplane.

In the mid 1930s, around the time that this aircraft

was being used to train R.A.F. Pilots,

the skies around the south coast of Britain

were actually a fairly empty place.

But with another war looming on the horizon,

the air ministry was facing a serious problem.

German's long-range zeppelin bombers

had terrorized London during the first world war,

and Britain's air defenses

struggled to cope with the attack.

To stand any chance of successfully defending

the country, the R.A.F. Needed a way of knowing

if an attack was imminent

so they could get their own fighters into the air.

This was a huge problem.

Scottish physicist Robert Watson watt

needed to overcome this hurdle.

Working as a meteorologist during the first world war,

watt detected the signals emitted

from lightning by bouncing radio waves

off of storm formations.

And in 1935, with another war looking increasingly likely,

he theorized that rather than bouncing radio waves

off of thunderstorms,

he could use them to detect incoming aircraft.

He named his invention radio detection and ranging,

eventually shortened to radar,

and it dramatically changed the outcome

of the second world war.

This is how watt's system worked.

In front of me, I have a slinky, which is stretched out

between me and a potential incoming aircraft.

And to work out the position of that incoming aircraft,

a radio wave would be sent out into the sky,

and I can simulate that by shaking this slinky.

So you can see that when I send out a radio wave

and it hits the aircraft, it gets reflected back,

and I can detect the aircraft's presence.

Because we know that radio waves travel at the speed of light,

by working out the time difference

between the time that the signal is sent out

and the time that it comes back,

I can determine how far away an aircraft is.

And this was something that had never been done before.

In 1935, watt successfully demonstrated

his new system to the air ministry, and by 1938,

the first five radar stations

covering aerial approaches

into London became operational.

The system was code named chain home,

and it relied on huge masts like this one to send

radio waves out into the sky.

By the outbreak of world war ii,

a network of 21 steel transmitters

and wooden receivers

were constructed along the Southern

and eastern coasts of the U.K.

all right.

Ah.

Oh.

That is a pretty amazing view.

The chain home system was the first application

of a radar air defense system anywhere in the world,

and it gave the British a vital edge over the Germans.

It was so powerful, it could even detect

a German aerial formation over 150 miles away.

And in 1939, the chain home low system was added,

which allowed observers to detect not only distance,

but also height.

And this is a really incredible piece of engineering.

80 years later, these incredible combat ships

are patrolling the world's

challenging coastal environments.

- Captain's on the bridge. - Carry on.

And crews aboard the independence variant

have the next generation of watt's engineering

breakthrough at their disposal...

the sea giraffe radar.

We need a radar that kind of packs a big radar punch,

but in a small package.

And that's what we get with the sea giraffe radar.

You want to come over here, sir, we will...

First, it goes through the nav plan.

Okay.

In congested, potentially-hostile waters,

this state-of-the-art radar system

helps the u.S.S. Independence

determine friend from foe.

Once we get here, we've got our critical points

in for contacting harbor control.

Okay.

There could be potentially several different small craft

coming in, up to 40 or 50 knots at the ship.

You need to have that capability,

where there's a lot of ambiguity

between the good guys,

the bad guys, and the in betweens.

The sea giraffe radar can detect 200 airborne

and up to 400 seaborne targets simultaneously.

But to simplify this complex picture,

its advanced radar technology

analyzes characteristics

such as altitude and speed to determine

if there's a threat within seconds.

Its ability to provide a very clear picture

to the operator is what makes it special.

We can separate the weak from the chaff from a radar picture

much better than a traditional radar would.

Even more incredible, this advanced radar system

is both smaller and lighter than a typical destroyer's.

It all is in keeping with our desire

to maintain speed and agility,

and it's a perfect fit for L.C.S.

the littoral combat ship fleet

navigates parts of the planet the U.S. Navy

once considered impossible.

I feel like we're doing something

that we haven't done before.

I truly think that this is pushing the boundaries.

And this inspired engineering will continue

to open up new horizons.

The opportunity going forward is limitless

with what we can do with these ships.

I'm just so extremely excited for the crew

that's gonna get the opportunity to sail in this ship

and take her around the world.

By learning from the pioneers of the past... Yes!

...up-scaling and developing innovations of their own,

engineers have written a new chapter in nautical design,

making the impossible... Possible.

She's basically one of a kind as far as warships goes.

I am sailing a ship that's unprecedented.

You can't find another ship in naval history

that's able to achieve similar features

as a littoral combat ship.

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