The Assassin (Sha ren zhe Tang Zhan)

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 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.