Original subtitles

Today on "Impossible engineering",

the kings of the sea.

On top of the ocean, the largest cruise ship in the world.

Nothing comes even close in terms of size.

And underneath, one of the most advanced submarines ever built.

The Virginia class is the stealthiest submarine

that the U.S. Navy has ever produced.

It took revolutionary engineering...

to make the impossible possible.

Captions by vitac... www.Vitac.Com

captions paid for by discovery communications

Royal Caribbean's Oasis class cruise ships

are truly kings of the sea.

Since 2009, they've held the title

as the largest class of passenger ships on the planet.

And today, a third Oasis-class vessel is under construction,

the biggest one yet...

longer, wider, and heavier

than any other that's come before it.

Sitting next to her makes me feel like

standing next to the skyscraper.

When it's finished,

the Harmony of the seas will be almost 8 times longer

than the statue of Liberty is high

and 2 times heavier

than the world's largest aircraft carrier.

Built with steel,

this king of the sea would be impossible

without some guidance from the engineers of the past.

For centuries, steelmaking

was an incredibly difficult and lengthy process

until the 1800s,

when inventor Henry Bessemer came up with a solution.

Traditionally, the wrought iron

was layered with charcoal and heated over days.

And the charcoal would diffuse into the iron,

and that would produce the steel qualities.

Very complex and difficult to achieve

and, therefore, very expensive, historically.

So, Bessemer developed an ingenious way

to mass produce steel.

And this is it... The Bessemer converter.

The converter's capacity is impressive,

but its real ingenuity is in how fast it creates steel.

Bessemer discovered that pumping air into iron

accelerates combustion,

increasing carbon reduction and burning off impurities,

resulting in quality steel in a fraction of the time.

To show how oxygen injection

really increases the combustion process,

I've got a simple demonstration here.

I've got a tray of charcoal.

With my thermal camera,

I can see the temperature of these coals at the moment

is around about 450° c.

So, now what I'm gonna do is start to blow pure oxygen

onto these coals and see the effect.

Wow. Look at that.

The impact is amazingly impressive.

Ah!

So, if I now look at the temperature,

it's gone up to 1,000° c, a hugely dramatic increase

in the temperature of these coals.

So Bessemer had found a really amazing process

to reduce the carbon in steel.

Mass production of steel took off,

and its elasticity and strength made it a hot commodity

for both railroad- and shipbuilders.

The Harmony of the seas

needs a staggering amount of steel.

Massive steel sheets are delivered

to the assembly plant by train.

Automated systems cut the sheets

into thousands of individual components.

The steel panels, girders, and smaller components

are welded into modular sections called blocks.

Individual sections are joined together,

forming what are called grand blocks.

Made of steel, there are 90 grand blocks

on the Harmony of the seas.

A custom-built gantry crane

lifts each grand block into the dry dock.

The 90 blocks come together

to form the world's largest passenger ship.

Sitting as tall as tower bridge,

it's as long as five jumbo jets and as wide as a soccer field.

When I really look at her, I'm amazed, always,

always, every single time, by the size of the ship.

It's big, but it's beautiful. It's awesome.

You can definitely call this ship a small city.

It can house almost 9,000 passengers and crew onboard.

But how does such a gargantuan structure

move across the open ocean?

The engines are the heart of the ship

and provide the power forward to the ship.

Without the engine, a ship is not alive.

Powering this king of the sea would be impossible

without help from one of history's great innovators...

and that innovator was Rudolf Diesel.

This is the hc oersted power station in Copenhagen.

And, inside, you'll find a giant version

of Mr. Diesel's early engine concept,

which changed the face of the industry globally.

When it first powered up in 1933,

the Diesel-powered hc oersted

was the largest engine of its kind.

It's 40 feet tall and weighs 1,400 tons.

Back in the day, it could produce

a mind-blowing 15 megawatts of power.

It's absolutely huge.

The real power of this engineering colossus

comes from Rudolph Diesel's brilliant design,

patented in 1894.

This is a fire piston,

and this little piece of kit was what inspired Rudolph Diesel

in his development of the Diesel engine.

And it works like this.

You have a small cylinder where you add a bit of cotton wool.

The cotton wool will work as fuel.

You have a little piston.

When you push down the piston here,

the air will be compressed, the temperature will increase,

and it will finally ignite the cotton wool.

And it goes something like this.

Compressing the air created heat,

the heat forced the cotton wool to burn, turning it into energy,

which forced the piston back up again.

The perpetual motion

within the compression ignition engine

works almost exactly the same way.

Air is drawn into the piston

and rapidly compressed, creating heat.

High-energy Diesel fuel is then added, causing combustion.

This pushes the piston out,

to start the process all over again.

I would say, within mechanical engineering,

it's the most important leap.

No doubt of that.

The hc oersted may have been a monster in its day,

but the Harmony of the seas's engines

are 6 times more powerful.

This is one of the most exciting days of the project.

Yo, Eivel, let's start her up.

But for the ship to be seaworthy,

it has to deliver beneath the waves, too.

So there are a few factors that are very important

for the fuel efficiency on the ship.

And, clearly, the biggest one is the hull shape.

The hull shape needs to be extremely well-designed

so that you have a good hydrodynamic shape.

So how do you design the perfect hull shape

for the largest passenger ship in the world?

The Harmony of the seas

is the largest cruise ship in the world.

Designing the perfect hull shape for this king of the sea

would be impossible had it not been

for an innovative breakthrough made over 150 years ago.

For centuries, shipbuilders had a kind of

one-size-fits-all notion about ship hulls.

There was one generic shape

that was considered the most efficient.

But there was no real way of testing this,

of working out how much drag, how much resistance

a hull would encounter as it moved through the water.

But in 1870, engineer William Froude

built a groundbreaking hydrodynamic testing facility.

And he used it to test differently shaped hull models

and drag them through the water on a steam-driven pulley.

We've got three different-shaped hulls...

A flat-faced square box,

a slightly streamlined rubber duck,

and then this sleek speedboat.

Like Froude's experiments,

Andrew makes sure each object is equally weighted

and tows the objects with a rope attached to a scale,

measuring the amount of hydrodynamic drag.

You can see this isn't slicing through the water.

It's sort of making a lot of turbulence.

If you look at the scales, 3, maybe even 4 kilos.

That's a lot of drag, a lot of resistance.

Next up, a slightly more streamlined rubber duck.

Well, that feels much lighter, and the scales bear that out...

Maybe 1.5, 2 kilos of force there.

And you can see the pool... Much less disturbed.

There are far fewer of those Eddies.

The duck's just skimming across the top of the water.

But I still think we can do better.

Let's try the powerboat.

This is almost effortless, maybe 600 or 700 grams, tops.

You can see much, much less disturbance to the water.

The pool's almost still, and even from this scale model,

you can see why we make boats in this streamline shape.

The key to Froude's discovery

lies in a model's wake pattern.

Froude's real Eureka moment was when he realized

that he could use a lure to relate the drag

on a scale model of a boat to one that was full-size.

Froude developed a formula,

now known as the Froude number.

That Froude number can then be used

to compare a model ship to a full-size one.

By making sure they've got the same Froude number,

you can work out how much drag the larger ship will experience,

work out how big an engine you need to install,

and it was this discovery that revolutionized

hydrodynamics and the shipbuilding industry.

Engineers of the Harmony of the seas

are using huge 30-foot models

to simulate a variety of sea conditions.

The result?

A super-efficient bow design,

a design that will be enhanced even further

using a cutting-edge system known as air lubrication.

Micro bubbles create an air stream under the ship.

This cushioning effect significantly reduces friction

and the amount of power needed to propel the ship,

increasing its efficiency by 5%.

This colossal cruise ship may be streamlined underwater,

but above, its sheer stature poses a huge challenge.

It's almost like driving a skyscraper at the seas.

We have to be able to control her

to the direct position what we want her to be in.

Their solution can be found

in a discovery made nearly 180 years ago.

During the 19th century, one engineering workhorse

prevailed in shipping across the sea.

And this is it... The paddle wheel.

Paddle steamers dominated the seas for decades,

but engineers changed course

with inspiration from an ancient invention.

For most of those early innovators,

the focus of their attention was this...

The Archimedes screw.

Dating back to the 3rd century bc,

this crank-operated contraption was used

to transfer low-lying water into irrigation ditches.

So we can see, if we turn the drill...

We start to get water transferring up the pipe

and then overspilling at the end of the pipe.

So inventors realized that they could apply this to a ship.

If you put the screw surface on the ship,

it can push the ship through the water.

But how this device

came to power the future of maritime engineering

actually came about by accident.

The colossal Harmony of the seas

is the largest passenger vessel in the world.

But how modern vessels like it maneuver through open water

actually came about by accident.

In 1836, engineer Francis Smith patented a revolving screw

similar to the Archimedes screw

that could be used to power a 6-ton ship.

But during testing,

Smith accidentally snapped the 3-foot long screw,

leading him to a surprising discovery...

The shorter piece drastically increased the boat's speed.

It was the precursor to the modern-day propeller.

In order to drive the largest cruise ship in the world,

the propellers on the Harmony of the seas

need to be of epic proportions.

Its 3 bronze propellers are 20 feet wide

and weigh almost 45 tons.

But this king of the sea can't just go fast,

it also has to be able to maneuver in and out of port.

This independence came about in the 1950s

through the revolutionary work of German engineer Josef Becker.

He designed something called the rudderpropeller,

which could both move and steer the ship.

On the Harmony of the seas,

the three pods act like airplane propellers,

pulling the ship through the water rather than pushing.

Utilizing 5,500-kilowatt bow thrusters,

they allow the captain's unparalleled control.

The pods can be turned in an instant,

getting the vessel into locations

that were previously off-limits to megaships.

But even with these pods,

making sure the ride will be comfortable

for all 6,000 passengers

poses a significant challenge.

The clearest issue we have is that the ship is not stationary.

It moves. It rolls. It heaves.

There's all kinds of movements and acceleration on the ship,

which makes it a little more complicated.

How do you keep such an immense vessel steady

in even the roughest seas?

What we've got is an ordinary bike wheel,

but we've filled the inner tube with concrete

just to make sure it's nice and heavy.

So, currently, this thing isn't spinning,

and that means it hasn't got any angular momentum.

And that means it's pretty easy just to make it spin around.

It's not very stable.

However, if we get this electric drill

and get the bike wheel spinning

and as we add more speed to the drill,

we're increasing the angular momentum.

Now, it's moving very fast, and now, if I give it a whack...

You can see this thing is stabilized.

It's the stabilizing effect of a gyroscope

that maritime engineers are interested in.

And in 1917, American inventor Elmer Sperry

used gyroscopic forces for the first time

to steady a large vessel in the sea.

He equipped the USS Henderson with two enormous gyro wheels.

Each wheel weighed 60 tons.

Inside, 10-foot flywheels spun

at an incredible 1,100 revs per minute,

creating huge amounts of angular momentum

in order to minimize the ship's roll.

It was a huge engineering breakthrough.

The Harmony of the seas

takes the stabilizing effect of the maritime gyroscope

into the 21st century.

Instead of using giant spinning wheels

like those employed on the USS Henderson,

the Harmony of the seas uses a small gyroscope as a sensor,

which controls mechanical stabilizers via computer.

So, in rough seas, what we can use to minimize

the roll and the movement of the ship are stabilizer fins.

A stabilizer blade is recessed

into each side of the ship.

They're deployed when seas get rough.

Stabilizer mostly counteracts the roll,

so the sideways movement of the ship.

So if the gyroscope feels the ship starts moving this way,

it asks the fin to exert force

so that it counteracts the movement here,

so it tries to always right the ship.

Harnessing the engineering breakthroughs of the past,

the Harmony of the seas is making history.

Also pushing maritime engineering to the limit

is the Virginia class.

To see these submarines being built,

it is truly a magical thing.

This king of the sea is one of the world's

most advanced submarines.

What we're looking at

is the 15th Virginia class submarine,

the USS Colorado.

She's 377 feet long.

She can dive to depths greater than 800 feet.

She can operate at speeds greater than 25 knots.

The Virginia class is one of the most advanced

nuclear-powered fast-attack submarines

ever produced for the U.S. Navy.

At the electric boat shipyard in Groton, Connecticut,

a 15th Virginia class vessel is under construction.

Starting with the first ship of the class,

it took 15 million hours to build that ship.

And with the Colorado,

we brought that cost down to 10 million hours.

That's the kind of effort that's required

to put one of these remarkable ships to sea.

These technological titans are as long as 26 cars.

Each sub weighs 7,800 tons.

That's 40 blue whales.

They're equipped with an advanced nuclear reactor

and can dive to depths of almost 800 feet

or inch across shallow water with pinpoint accuracy,

thanks to a control room that's equipped

with an automated navigation system.

To create this king of the sea required monumental engineering,

which would have been impossible

had it not been for great innovators of the past.

The Virginia class

is one of the world's most advanced attack submarines,

but it owes its existence to the innovators of the past...

particularly to an invention

developed during the American revolutionary war

by David bushnell.

And this is it, the turtle...

The first submersible used in recorded underwater combat.

Bushnell's plan for the turtle

was to sneak up on the British enemy ships

moored in New York harbor.

The vessel had lots of weights in it

to help it sink into the water,

and underneath the base, there was a ballast tank,

which would be filled with water.

And the operator, a man called Ezra Lee,

would pump the water in and out of the tank

to help sink to the right depth.

The turtle's weapon, a keg of gunpowder,

was attached to the back of the wooden hull.

It would be attached by this drill,

which would be literally hand-drilled

into the base of the ship.

Unfortunately for the pilot Ezra Lee,

the British fleet had metal hulls.

By sheer bad luck,

Ezra Lee wasn't able to drill into the ship's hull,

so the turtle was a bit of a failure.

But having said that,

it did set the precedent for submersible combat,

and the principles of ballast tanks and propulsion

still to this day remain on all submarines.

Thanks to a super-sized system

of internal and external ballast tanks,

the Virginia class submarine can reach depths of about 800 feet.

We have five external ballast tanks

that are normally filled with air

when I'm riding on the surface.

When it is time for us to dive,

we'll open vents on those ballast tanks.

There's grates on the bottom of the ship

that allow water to come in, displace the air,

making the ship just slightly negatively buoyant.

We then proceed down to the depth that we want to go to,

and we use internal ballast tanks

to make the ship neutrally buoyant

that then we can progress on our way

whatever depth we choose.

The crew on board the Virginia class

have an abundance of cutting-edge controls

at their fingertips,

one of which is replacing the most iconic feature

in submarine history.

The periscope has been a key component on the submarine

for over 100 years,

but engineers on the Virginia class

are replacing the periscope

with a state-of-the-art photonic mast.

The photonic system is a mast

with a sophisticated camera system

that allows what would normally be displayed just in a periscope

to displayed on wide-screen monitors throughout the ship.

I used to have to have an optical periscope that came down,

which drove the construction of the submarine

and the orientation of all of the rooms on the submarine.

Bulky periscopes force most submarine control rooms

to be located on a cramped upper deck.

On the Virginia class, the compact imaging equipment

is housed in a part of the submarine known as the sail.

This allows the sub's control room

to be built on the wider second deck.

My control room that I'm standing in right now

houses all of the important decision makers.

It really brings the crew together

to operate as a team, as a unit.

It's not just the photonic system

that makes the Virginia class revolutionary.

A virtually silent propeller, known as a propulsor,

drives the nearly 400-foot submarine,

and a sophisticated system of sonar arrays

allows it to map its way across the ocean floor.

The ability to put literally tens of thousands

of horsepower into the main engines,

into the propeller, and yet be so quiet...

The level of technology required to do that is amazing.

Warship here. 0-5-4 rate...

The Virginia class is virtually undetectable

as it travels through the world's oceans.

But how do you construct the perfect hull,

one that's optimized for sub-surface speed

and maneuverability?

It's a task that would be impossible without help

from some of history's greatest naval engineers.

The Virginia class submarine is a king of the sea.

Helping it speed through the waters at 25 knots

is a cutting-edge hull.

But this design stands on the shoulders of history's giants.

During world war ii, submarines were essentially surface ships

that could submerge themselves for up to 48 hours.

But underwater, the vessels were cumbersome and inefficient.

Admiral Charles Momsen was determined to come up with

a more efficient design.

The U.S. naval officer

commissioned over 25 large-scaled models.

Those models ultimately resulted in the teardrop hull form

that became the standard for all modern submarines.

To appreciate this game-changing teardrop hull design,

Matt analyzes the hydrodynamic qualities

by injecting dye into the tank.

So, we've got the model in the water now.

We're towing it below the surface.

It's coming into the window now and right into the dye field.

And the bow goes through the dye.

Wow, look at it!

Look how smooth the flow is off the stern

as it passes through that dye field.

That's showing me we have very low resistance.

The hull's teardrop shape

dramatically reduces both frictional and form drag.

So after countless hours, tests, and calculations,

admiral Momsen and his team had done it,

and this is the result... The USS albacore.

The teardrop hull of the albacore

changed the face of submarine design.

By getting away from that ship-type hull form

and going to a true submerged-type hull form,

we have the baseline for all subs to come.

It's been 60 years

since the albacore first set sail,

and the U.S. Navy's latest and greatest submarine,

the Virginia class,

is using admiral Momsen's game-changing teardrop hull.

Each submarine is made up of four super-sized modules

that, when combined, measure almost 400 feet.

The vessel contains around one million components

and requires 10 million man-hours to build.

We have 3,600 dedicated men and women

who take raw steel plate, pipe, and cable

and create completed 2,000-ton modules.

Raw steel plate is brought in.

The cut machines automatically cut the plate

to the right dimensions.

In the case of pressure hull structure,

it's rolled to get that circular shape for the pressure hull.

It takes 5,000 tons of force to form the steel

into the iconic submarine shape.

Each submarine segment lies horizontally

so the decks can be slid in.

When you pair up the last hull section

and you actually have the ship look like

a whole ship together in a bay,

it's really exciting to see it all come together.

Transporting this monumental structure

to its natural habitat is an impressive sight to see.

But for the Virginia class to be successful

in its wide variety of surveillance

and reconnaissance missions,

it must be able to stay underwater for months at a time.

This crew of 135 sailors

have to be able to go anywhere in the world,

deploy from their home port,

and be operating in any ocean

and not be concerned about the amount of fuel consumption.

So how do you propel a submarine to the most remote parts

of the globe without refueling?

To be effective, the Virginia class submarine

must stay submerged for months at a time.

But this would be impossible

without the innovators of the past.

The world's first peacetime use of nuclear power

occurred when the U.S. government switched on

the experimental breeder reactor in Idaho in 1951.

It temporarily powered the town of Arco,

paving the way for domestic nuclear power.

But captain Hyman rickover of the United States Navy

had other ideas.

He saw the potential

for using this technology in a submarine.

Rickover was an incredible pioneer.

The problem with powering submarines is that most forms

of power for propulsion require air,

so the submarines had to resurface,

or the alternative would be battery,

but they just didn't last.

Rickover was convinced

that the fundamental process of a nuclear reaction

to boil water and create steam could power a submarine.

Nuclear reactors are just very large ways of boiling water.

And here I've got a steam cleaner

that's going to represent my nuclear reactor.

I've got some water, and when I pull the trigger,

it boils the water, turning it into steam.

As I direct the steam towards my turbine...

it starts to generate electricity,

and that turns on my light.

The difference between my little reactor here

and this enormous one here

is in the way that the water is heated.

And the answer lies at the very heart of the core itself.

Nuclear fuel rods contain thousands of uranium pellets,

and it's the uranium atoms that split,

causing a chain reaction

that generates vast amounts of energy in the form of heat.

The result is an almost limitless supply

of power that can keep on producing for years.

The problem rickover faced was scaling down something

as huge as a nuclear reactor

down to the size of something that could fit into a submarine

and still provide the power.

What rickover came up with

was the world's first pressurized water reactor.

The core inside his reactor vessel

heats a loop of pressurized water.

This in turn vaporized water in a secondary loop,

creating steam to drive the main turbine,

which also produces electricity.

The nautilus was launched in 1954.

This pioneering nuclear vessel traveled 1,300 miles

in less than 90 hours fully submerged.

This was a huge game changer in submarine engineering.

Previously, submarines could only stay underwater

for up to 48 hours.

Now there was absolutely no need to resurface.

Captain Rickover's nautilus reactor

needs to be refueled every two years.

The designers of the Virginia class submarine

are taking this technology to an unprecedented level.

The Virginia class submarine is powered by a nuclear reactor

that has been designed to last the life of the ship.

Converting seawater to steam,

this top-secret reactor plant

is capable of powering the vessel

for nearly one million miles without refueling.

The reactor on the Virginia class

is the most advanced reactor that the U.S. Navy has produced.

12 Virginia class subs are now in service,

each equipped with a state-of-the-art nuclear reactor

that allows the vessels to remain underwater

for months at a time.

But keeping the crew safe during long-term subsurface missions

is a huge challenge.

We have an enclosed environment,

and so, clearly, we have to monitor

the atmospheric controls on board

and the levels of the oxygen, the carbon dioxide,

and other trace gases to make sure

that it remains habitable for the sailors.

So, how does the sub replenish oxygen levels

without ever going to the surface?

The answer comes from the early 1800s through the work

of English chemist William Nicholson.

Inspired by the electric battery,

Nicholson experimented with placing battery leads in water.

The result was a chemical reaction

now known as electrolysis.

This is a simple demonstration of electrolysis.

I first have my water for the electrolyzer.

Okay.

Two water-filled test tubes

are placed over the submerged negative and positive electrodes

before the electrical current is switched on.

And you can start to see immediately the gas bubbles

forming on the electrodes here.

The negative electrode is generating hydrogen.

And the positive electrode is generating oxygen.

And so each of these jars

now has displaced the water with the gas.

This reaction is caused

by the positive and negative electrodes

attracting and separating the oxygen

and hydrogen molecules in the water.

The engineers of the Virginia class

are using Nicholson's groundbreaking work

to create life-sustaining conditions underwater

for months on end.

We distribute the oxygen throughout the ship

and then remove the hydrogen

so that we can maintain levels right at 20%,

just like normal air.

The U.S. Navy's advanced

integrated low-pressure electrolyzer

can create over 200 cubic feet of oxygen per hour.

Potentially toxic carbon dioxide

is removed by a sophisticated amine-based removal plant.

If you could imagine driving your car

for six months straight, 24 hours a day,

it's truly a testament to the engineers who designed it,

the people who built it,

and those 135 sailors who operate and maintain it

on a day-to-day basis.

By drawing on the innovators of the past,

adapting their ideas, honing them,

and making trailblazing innovations of their own,

the engineers of the Harmony of the seas

and the Virginia class

have made these vessels the kings of the sea.

They've succeeded in making the impossible possible.

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