in forgotten manuscripts
lie the naval inventions of our distant past. The "Ancient Discoveries"
team of model makers, underwater detectives,
and elite naval commandos are seeking to rediscover
these lost military designs. They are performing a series of
life-threatening experiments. Their results reveal that
today's naval devices are based on the ingenious blueprints
laid down by naval engineers thousands of years ago. This is the story of
ancient naval technology. [music playing] To explore ancient
naval warfare, we must first piece together
the story of the sea. 2/3 of the Earth's surface
is covered with water. It has been a battleground
for over 5,000 years. It doesn't matter where
you are on planet Earth, if you're by the sea,
you had to have a navy. Crossing landmasses was both
expensive and very inefficient. Taking a boat from
one area to the other was approximately
six times quicker. It was a no-brainer. NARRATOR: The drive to build
quicker, larger, more powerful battleships launched an
ancient naval arms race. We are finding
evidence of highly toxic biological warfare,
high-impact explosive grenades, underwater attack units that
operate like US Navy Seals, and visionary devices able
to turn sea into solid land. Every ancient civilization, from
the Egyptians, to the Greeks, to the Romans, lived and
died by their innovations in naval technology. And perhaps the most lethal
of all such inventions came not from the
West, but the East. South Korea is a glittering
jewel of Eastern Asia. Yet, for centuries, it has
been a target for invasion by its two monster
neighbors, China and Japan. Japan created some of the most
terrifying soldiers in history, the samurai warriors. And China had the largest
standing army in all antiquity. Korea stood at a
crossroads, surrounded by two aggressive superpowers. To defend their shores, the
small and vulnerable nation of Korea was forced to turn
to technology to survive. YEON-SEOK CHAE:
[speaking korean] INTERPRETER: In the
later Koryo Dynasty, the development of science
meant we had advanced military technology. NARRATOR: In 1591, the
Koreans developed a vessel that would become known
as the turtle ship. Within six months,
turtle ship crews were being trained for a
conflict that would become known as The Engine War. It pitted Korea against
the Japanese force over three times
greater in number. INTERPRETER: At the
time of The Engine War, six gun ports were installed
on each side of the ship, and a gun port at each
side of the dragon's head. NARRATOR: These cannons
could unleash barrages of ballistic missiles. YEON-SEOK CHAE:
[speaking korean] INTERPRETER: You might Imagine
that blasting powder balls were used in the cannons,
but in the early ages, wooden arrows with
iron wings were used. The wooden arrows
were 6 feet long and designed to make a huge
hole in the enemy's ships. And the secret behind
the weapon's potency was that iron wings were
attached to make the arrow more deadly. NARRATOR: These
ship-to-ship missiles struck at speeds of
over 200 miles per hour. The secret of their power lay in
the pioneering design developed by the Korean engineers. With its superior
firepower, the turtle ship was able to demolish Japanese
targets at long range, safe from counterattack. Just as US aircraft carriers
do in the 21st century. In spite of the lethal
firepower of the turtle ship, the Koreans were facing
a superior force. If the enemy broke
the first attack and managed to get in close,
the ships and the battle might be lost. The Korean military
engineers were forced to invent a
contingency strategy. Unbelievably, the solution
was to convert the turtle ship into a mobile floating tank. The War Museum in Seoul, Korea. Here, one of these
extraordinary battleships has been reconstructed. JANG HAK-KEON: [speaking korean] INTERPRETER: The
turtle ships deserves to be compared to a tank,
because it acted as a ramming ship. Its primary role was
breaking through enemy lines and destroying their
front line of ships, then, the rest of the Korean
fleet struck forward. NARRATOR: The ship was designed
to ram directly against enemy vessels. 400 tons of boat
powered by 80 oarsmen would crash into enemy ships. But in order to withstand
such collisions, its design was critical. The ship's crew and rowers were
shielded inside the vessel. Outside, the turtle ship
was clad in iron plating. And these spikes were
not just for decoration. [speaking korean] INTERPRETER: Japanese ships
would approach the Korean ships at high speed and
jump on the deck to kill the Korean soldiers. This was because their ships
were much higher in the water. In order to prevent
this happening, spikes were nailed to the roof. NARRATOR: Each plate
carried a 2-foot long spike that would impale
enemy invaders who risked an aggressive boarding. The turtle ship had become
a giant iron cactus. But the spikes were
not its only defense. Mounted on the front of the
destroyer where the gaping jaws of a majestic dragon. Yet, this was no
decorative figure head. Ancient stories claim that
contained within its mouth was a deadly secret weapon. INTERPRETER: The front part of
the turtle ship it was designed as a dragon head with a
mouth which served as a gun port and a small cannon
of mythical power was placed there. A projector was also
installed that could release dense toxic smoke generated
by burning a mixture of sulfur and salt peter. NARRATOR: The dragon head was
a prototype chemical weapon. It had the potential to
deliver poison gas at an enemy. This predated the use of
mustard gas in World War I by 500 years, and began the
technology of chemical warfare, a terrifying military
option to this day. But poison gas is only effective
if the soldier can direct it at the enemy, away
from his own troops. Richard Windley is an historian
and one of the world's leading model makers. He is fascinated by stories
that the Koreans had mastered the ability to deliver
chemical gas to their enemies. He has constructed a replica
of the dragon's head. He is about to test the
effectiveness of the delivery system. If we think about the use of
gassing in the First World War, obviously, it was a very,
very dangerous technique. It only needed
the wind to change and the gas could
actually affect the people who were
trying to deploy it rather than the enemy. So it is a risky stratagem. I've got one of the
little charges here. I'm gonna light this. Pop it in the pot, put
the lid back on fairly-- fairly quickly, and
then, hopefully, we should get some smoke. NARRATOR: At first, the smoke
lingers around the head. This would be lethal
for attacking troops. But then, the wind picks it up. RICHARD WINDLEY: The assumption
is with-- with something this, that it was projecting the
smoke a considerable distance. Well, if you try
blowing anything in air, you can't blow it more than
probably about 10 feet at most. So really, it was just a way of
getting this stuff into the air and dispersing it. But I think that with, given the
right kind of maneuverability of these turtle ships, it
probably was a viable option. And what we have to
remember is these guys were heavily outnumbered, and
anything that would give them an advantage or that
would save their culture and their civilization
and their country was something that they would
fight very hard to realize. NARRATOR: If the
turtle ship captains had been able to position
themselves upwind of the enemy, the poisonous gas could
have been delivered without the Korean commanders
killing their own troops. The use of toxic gas remained
at the mercy of the wind until the delivery of gas by
mortar in the trenches of World War I. From its lethal arsenal,
to the ramming potential of its spiked cladding,
the turtle ship was a weapon capable of
changing the tide of war. But Eastern Asia was home
to an even more lethal seafaring super weapon. One of the greatest underwater
discoveries of the modern age has shown how high explosives
rocked the high seas almost a millennium ago. [bomb exploding] Nearly 1,000 years ago,
a great Mongol warlord launched a naval fleet that
would dwarf any modern navy. It had over 10 times
more battleships than all the ships of the
entire American Navy today. Onboard was the most
lethal military hardware available at the time. Evidence lying 50
feet beneath the waves is suggesting that the Mongol
generals supplied their marines with high-explosive grenades. In the 13th century, Kublai
Khan was the ruthless warlord who commanded an aggressive
expansionist superpower. At the height of its
power, the Mongol Empire covered 12 million square
miles, over three times the size of the entire United States. But one nation held
out against the might of the largest continuous
superpower in history. That nation was Japan. [music playing] Kublai Khan wanted to stamp
out the Japanese pirates from the east whose raids were
crippling Mongol trade routes. In the summer of 1281, Japan's
fate hung in the balance. INTERPRETER: If Japan lost, it
wouldn't be the same country. This was the first invasion
attempt from abroad, and the fact that people
came together to repel it perhaps engendered a
sense of nationhood. NARRATOR: He prepared
an invasion fleet of epic proportions. The largest fleets ever put
together in the medieval world were those that Kublai Khan
produced for his invasions of Japan in 1274 and 1281. The second and largest of these
comprise more than 4,000 ships and 100,000 soldiers. This is probably the largest
naval flotilla ever assembled prior to D-Day. NARRATOR: Just as with the
Normandy landings in the Second World War, committing such
an enormous fleet to sea was a huge gamble. If it paid off, it
would destroy Japan. But just off the coast,
a fierce storm blew up. Severe gales whipped the seas
into a churning fury that destroyed the entire fleet. Thousands of lives were lost. RANDALL SASAKI: Japanese people
believe that their nation was protected by God, and
when the Mongols attacked, historical record indicate
that there was a great typhoon. And people believe that this
wind were brought by gods. NARRATOR: They called it divine
wind, which in Japanese, is pronounced kamikaze. This would be the rallying
cry of Japanese suicide bomber pilots who destroyed American
ships and morale in World War II 500 years later. [music playing, bombs exploding] Just off the Japanese coast at
a place called Takashima Bay, archaeologists have made
one of the world's most incredible discoveries. Khan's lost fleet has at last
been found beneath the waves. A Takashima Museum,
the exquisite remains are preserved. Takashima underwater
archaeology site is one of the first underwater
excavation that took place, and it's one of
the biggest center for the underwater archaeology. NARRATOR: There are iron
swords, stone catapult balls, and this huge anchor. These are wooden artifact
that were excavated. And it is mainly parts of ships,
and maybe ship board material. NARRATOR: But the most
intriguing of all the artifacts from the Takashima
Bay wrecks are these simple, hollow spheres. Closer inspection reveals
evidence of explosion damage. And intriguingly,
the damage appears to come from a force inside
the objects themselves. Were these devices the world's
first high-explosive grenades? [explosion] In the sacred confines of
a Hakozaki Shrine Museum in Fukuoka, Japan lies a clue
that could be the final piece in the puzzle, an
ancient scroll guarded by the high priests of one of
Japan's three great shrines. INTERPRETER: The scroll depicts
events from around 700 years ago from this area where the
Mongol invasion first started. The Mongols were an
equestrian people, but had a device that
utilized gunpowder. The Japanese had never before
encountered explosives and were very surprised. NARRATOR: Upon close inspection,
one sequence in the scroll contains exciting evidence
of the use of the balls at the Takashima Bay wreck. The scrolls tell of a
lethal explosive weapon like a modern grenade. The ancients called
it a tetsuho. CHRIS PEERS: Six
of these weapons have actually been discovered
by archaeologists, proving that the contemporary
evidence was correct, and that weapons of this
level of sophistication and deadliness were, in
fact, used as early as 1281. NARRATOR: X-rays of
unexploded tetsuho reveal that they were filled not
just with gunpowder, but also with deadly shards of iron. The tetsuho could have been
launched using catapults, or simply thrown by hand, like
a modern infantry grenade. The results would have left the
Japanese shocked and terrified. Japanese has never seen such
a weapon that makes loud noise and explode. And also, it's gonna slice
the enemy's armor and hand and everywhere, so it's gonna
lower the moral of the enemies. NARRATOR: But just how
devastating these ancient bombs really were has
never been tested. Until now. Ancient technology
expert Richard Windley is investigating the
killing potential of the ancient tetsuho. He has created a reconstruction
of the fabled Japanese grenade. These are made of kind of
heavy stoneware pottery, very crude, very roughly made, but
quite heavy and quite large. What we're looking at is
something which probably replicates what we would now
call a modern fragmentation grenade. So this is intended to cause
as much physical damage as is possible to cause. It was actually
quite a nasty weapon. NARRATOR: Now comes
the moment of truth for the ancient tetsuho. our weapons test will
involve highly dangerous live explosives, so we've
called in the pyrotechnics team behind "James Bond" and
other Hollywood blockbusters. We're gonna look
around hay bales, so we've got to be close enough. Protect that with hay bales
and sandbag wall between that and the explosive charge. NARRATOR: An ancient tetsuho
has not been exploded for nearly 1,000 years. The exact blast
radius is not known. So the team has
retreated 200 feet. The tetsuho is believed to
create an incredible blinding flash upon ignition. To capture this, we've brought
in specialist slow motion cinematography. TECHNICIAN: Firing in 3, 2, 1. [explosion] NARRATOR: Captured at
10,000 frames per second, this footage unveils
the terrifying inferno that would have engulfed
the Japanese warriors. The tetsuho ignites at
temperatures of up to 700 degrees Fahrenheit. The explosion would have
a 100% lethality rate at a blast radius of 20 feet. Our groundbreaking
experiment has proved that the Mongols could
have literally incinerated Japan's navy. But not all naval
innovations involved complicated explosive chemistry. The Romans developed a piece
of wooden military hardware that looks as dramatic
as it really is. It changed the course of an
entire war in only a few hours. 2,000 years ago, the dominant
superpower in the ancient world was the great empire
of Rome policed by the legions, the first
full-time professional army in history. The Roman Empire spanned across
2 and 1/2 million square miles of land. But in the third century
BC, a rival superpower grew up in the desert
of North Africa. Its name was Carthage. Carthage, initially an outpost
of Phoenicia and Palestine, becomes the trading superpower
of the Mediterranean. And the struggle between
Rome and Carthage is a struggle for power and
control over trade and land and critical supplies,
most important of which are things like grain. NARRATOR: On one hand
stood Rome's colossal army of over 350,000 well-drilled
and well-armed soldiers, on the other, Carthage's
domination of the sea. They fight first over Sicily,
which is an enormous granary either for Rome or for Carthage. And its life and death. No grain, no bread, no success. NARRATOR: At the
heart of Carthaginian naval power was its
magnificent circular harbor. Built to house over
200 super destroyers, the harbor was Carthage's
military headquarters. While a modern US aircraft
carrier takes five years to build, Carthaginian
engineers constructed warships in the blink of an eye. Ancient accounts tell of such
ships being built in 40 days from the moment the
tree was first felled. Between Carthage and Rome
lay the Mediterranean Sea, a battlefield of almost
one million square miles. The Mediterranean
became the focal point for a fearsome power struggle. Key ancient navies
could outperform others not by numbers, but by skill. The Athenians, the
Rhodians, the Carthaginians had major advantages
in seafaring skills. NARRATOR: But 2,500
years ago, the Roman navy was almost nonexistent,
save for a few river patrol boats, the remains of which now
lie in Mainz Museum, Germany. The Mainz's type A boats
were elegantly designed. They are very narrow and long. There's definitely no evidence
that these ships had been used for fighting, because they
are too small, too narrow. But they will evidently
used to control the river. NARRATOR: But Rome's riverboats
would be no match for the might of Carthage's navy. How could the Roman
generals bring their military superiority
onto the open ocean? They copy
Carthaginian vessels, they mass produce them, and
they develop new tactics to negate Carthaginian skill
and replace it with Roman power. They turn sea battle
into land battle. NARRATOR: The Roman
military engineers started building boats with
a super destroyer known as the Queen Kareem at
the head of the fleet. 100 feet long, it was the fast
attack heavy troop carrier of the ancient world. The Queen Kareem was
a huge naval vessel. There are probably
700 people rowing it. These are incredibly
expensive, incredibly complex bits of machinery. NARRATOR: But the troops carried
by the Queen Kareems were not Marines or Navy Seals. They were legionnaires, infantry
men used to fighting on land. The Romans needed to develop
a way of getting their legions onto the decks of
the Punic warships as quickly as possible. Roman naval engineers proposed
an ingenious solution, a 40-foot long 2-ton
called a corvus. It's basically a boarding
ramp with a large spike on the front. You drop the ramp, the spike
sticks in the enemy ship, and your Roman legion
rushes across and chops up the Carthaginians,
who are not expecting to fight this kind of battle. They're expecting to fight
a ship on ship battle, not a man to man in combat. NARRATOR: But would the
ambitious new weapon work in battle? Richard Windley
is investigating. He has created a half-sized
version of the corvus. The real corvus was something
like 36 to 40 feet in length. It was 4 feet wide. It was probably weighing 2 to
3 tons, possibly even more. And the mast with
the pulley on the top was something like
20 to 25 feet high. This was a enormous
piece of kit. NARRATOR: Lifting 2
tons of war machine on a single hemp rope with only
manpower requires coordination. OK, hold. NARRATOR: If the team
or the rope slip, Richard and his assistants
could be badly injured. RICHARD WINDLEY: Steve's off. Gently. Tie off. OK, I've got it. Clear, please. NARRATOR: When released,
there were no second chances. Aim had to be perfect. 3, 2, 1. [music playing] Right, well, it looks as though
we're pretty well impaled. It is effective at locking
the two ships together, and it would have been
reasonably effective in the right circumstances. NARRATOR: However, Richard's
experiment has revealed a weakness with the corvus. It would've needed probably
quite a lot of training to get the timing exactly right,
the release exactly right. Again, with the ships pitching
and waving, moving one against the other,
the timing would have been absolutely crucial. NARRATOR: Even this
scaled down example is a struggle for Richard
and his assistants to raise a second time. And Richard's model was
revealing further problems. The problem with this
is we're on dry land. We're on a stationary position. You know, one can imagine
that ships at sea amidst all the turmoil of battle,
ships waving, twisting, moving around, this thing would be
really very, very difficult to maneuver. NARRATOR: The 40-foot height
upset balance and turned a slick attack ship
into a clumsy vessel, difficult to maneuver. The immense weight
towering above the deck of a rolling cruiser
made the vessel unstable. If the seas picked up, the
top heavy device could easily flip the ship over. But Carthage needed
to be crushed at sea. Despite the risks, the
Romans installed the device. Would the calculated
gamble pay off? In 245 BC, the Romans
launched the largest fleet of attack ships they had
ever put to sea, all armed with a corvus. But only a few miles out of
harbor, they hit rough seas. The instability of the
vessel caused by the corvus was too much for the
captains, and they could not control their ships. It was too cumbersome. It was too bulky. It breaks all the rules,
and the Romans invariably find themselves in a storm. And not being very good seamen,
they don't see it coming, and they don't know
how to deal with it, so they lose their fleet. NARRATOR: 270 vessels went down
with a loss of 100,000 men, the greatest loss of any
maritime force in history. All because of these
simple planks of wood. This is a very ungainly,
cumbersome machine. And really, it was a quick fix. It was a very ad hoc
solution to a problem. The actual application of it
had huge detrimental effects to the maneuverability
of the ship, which was slow and ponderous already. NARRATOR: The Romans abandoned
the idea of the corvus, and it was never adopted by
any military force ever again. But not all naval battles
were fought above the waves. The quest for maritime
supremacy drove ancient military engineers
to look beneath the ocean's surface, pushing human
endurance and subaqua technology to the limit, transforming
ordinary seamen into the most high-tech elite
special forces in history. The strategic
importance of the oceans has been vital
throughout history. We're looking at a world
connected by oceanic transport. It's the only way of
moving anything that weighs more than a few hundred pounds. NARRATOR: The need to
control the sea produced a technological and
tactical arms race that has created most
of the breakthroughs in military technology. It is the world's
naval forces that have produced most
of the innovations in warfare throughout the ages. Most of the modern
sophisticated weapons in use today, including
airplanes, bombers, tanks, you name it, they
had to be the best, because otherwise, they were
going to lose the war at sea. NARRATOR: From the US battle
fleet of the 21st century, through the British domination
of the waves during her empire, to the massive
expansion of Greece across the Mediterranean
3,000 years ago, the nation that ruled the
waves ruled the world. But there was then,
and still is today, a need not just to
rule the oceans, but rule the water beneath. Submarine technology and special
forces groups in modern armies are the rapier by which generals
can turn battles, and even wars, because undersea
attacks can be secret, unseen by enemies centuries. Every modern navy has
its own elite squadron of highly trained specialist
underwater attack troops. Paul Haynes is a retired
commando from the Royal Marines. Transportation overland
generally requires vehicles. All these are less discreet
and less covert than deploying personnel subsurface. NARRATOR: But many special
forces men and women might be surprised to discover
that covert diving technology has been around much
longer than we imagine. And the most
important technology for underwater missions is to
supply something we all need. It's oxygen. So that's
the fundamental requirement of any diver, a means
of delivering oxygen to him to sustain life. NARRATOR: The simplest way to do
this is with a tube or snorkel. 2,500 years ago
in ancient Greece, there are accounts of a
spy named Silas mounting an audacious underwater mission
to release enemy Persian ships from their moorings
without being detected. The ancient accounts say that
the secret behind his success was a mysterious hollow device
like an ancient snorkel. Richard Windley has been
investigating diving technology in the ancient world. It's often thought that
the idea for using snorkels was derived from watching
elephants when they were swimming. These are actually bamboo. The original would have been the
giant reed, arundo donax, which grew all around
the Mediterranean. It grew to fairly large sizes. The device at the bottom is
something I've added myself, because obviously,
if you've simply got a tube in your mouth. You've got to look
upwards at all time, and it's a bit
difficult to, you know, achieve any kind of
underwater tasks. NARRATOR: The texts show the
diver at a depth of 15 feet, but due to increased
pressure on the lungs, snorkels are only effective
down to around two feet. So Paul believes the ancient
illustrations are wrong. All snorkels have limitations. It depends upon the length
of the snorkel primarily. If it's too long, you'll
have significant challenges in trying to breathe. So there is an optimum
length for any snorkel. NARRATOR: Richard's
replica ancient snorkel is three feet long, longer
than the optimum two feet. Paul takes the snorkel
to its maximum depth. [music playing] The results impress even this
experienced military diver. That was actually
quite comfortable. I felt-- felt like
a normal snorkel. As long as you stay shallow,
it really covered it. It became quite apparent as
you submerged and went deeper, you could begin to feel the
additional strain and pressures on your lungs. NARRATOR: The test reveals that
the ancient snorkel will supply oxygen to the diver
very effectively, but only to a maximum
operating depth of three feet. At this depth, the diver
might be visible to sentries. For an operation
to be truly covert, military technicians
have tried over centuries to create equipment
that leaves no trace. Even modern scuba
gear leaves a trail of bubbles that might be
spotted by a keen-eyed sentry. To solve this problem,
modern special forces use a device known
as a rebreather. Incredibly, this
device allows the diver to breathe back in the air
they have just breathed out, leaving no bubbles at all. What we have here today is
the stealth rebreather, which is the most modern
military in the world, life support system
there is at the moment. The divers breathe
in from his bags. [inaudible] as they're called,
breathe in through the hoses into the bags, and the gas
then goes through what's called a scrubber. And that absorbs carbon
dioxide that you produce. Then back around to the divers,
so he inhales fresh gas. NARRATOR: But amazingly, this
ultra high tech equipment might have its roots in a device
created for assault troops thousands of years ago. In 1000 BC, Assyria
was a major superpower of the ancient world,
controlling an empire of thousands of square miles. Within its dominion
and along its borders were plateaus and
fertile valleys crisscrossed with rivers. As the empire grew,
her armies needed to attack across
these waterways. There is evidence 300 miles
away in London, England that offers a clue as to
how they approached this. The British Museum in London
contains the world's largest collection of ancient artifacts. Here, Dr. John Bevan is
investigating evidence that suggests the ancient
Assyrians used a rebreathing device nearly 3,000 years ago. [music playing] The museum contains a
relief carving that depicts an Assyrian military assault.
Siege tactics, chariots, and heavy infantry
are all shown, but a portion of the relief
tells the story of a river assault. DR. JOHN BEVAN: This
depicts a river crossing of the Assyrian army,
possibly the Euphrates. And it's a massive operation,
a huge logistical problem. You've got to get all your
troops, and your horses, and your chariots
across the river. And it's a wonderful
illustration of the problems they're
facing in crossing a river. NARRATOR: There is
evidence in the carving of a mysterious piece
of military technology. DR. JOHN BEVAN: This has
puzzled people for a long time. It shows an Assyrian
soldier holding what appears to be a goat--
an inflated goat skin or a bladder underneath him. It's strapped to his body. He's got a tube into his mouth. Now, some people have
thought that this depicts a diver swimming
along under water in a clandestine or covert way. NARRATOR: The swimmer would
have breathed oxygen in and out of the bag. Many believe that this is
evidence of the world's first underwater rebreather. Others predict that the device
would never have worked. Entering the debate is the
"Ancient Discoveries" team. Richard Windley has created a
replica of the ancient Assyrian rebreather. Today, for the first
time, our intrepid trio of scholar, ancient model
maker, and military commando have returned to
Pinewood's diving stage to test Richard's creation. The trials will require Paul
to submerge beneath the water with no oxygen supply. He will only be able to breathe
the air he has already breathed out. There is evidence from
nearly 3,000 years ago of covert underwater
assault technology. These images suggest that the
ancient Assyrians developed a device that allowed them to
mount an attack while breathing air underwater without
leaving any trace of bubbles, the perfect weapon for a
covert subsurface attack. Agent model maker
Richard Windley has built a model of the device. RICHARD WINDLEY: We think
possibly the original versions of these may have been
an entire animal skin. And these had to be sealed. And the way they did that was to
stitch them and then use, like, a slurry of all sorts of
bizarre mixtures like honey and beeswax. This actually does a fairly
good job of-- of waterproofing. NARRATOR: Today, ex-Royal
Marines commander Paul Haynes is going to test the model. Is this the first
ever completely covert military equipment? [music playing] The experiment gives
a clear result. PAUL HAYNES: The challenge
is straight away. It's positive buoyancy. So it immediately wants to
lift you to the surface. NARRATOR: Air has 800 times
less density than water, causing the breathing bag to
shoot upwards to the surface. Underwater operations would
have been almost impossible, yet ancient reliefs clearly
show it being used in operation. Ancient historian John Bevan
has interpreted this evidence. DR. JOHN BEVAN: The
soldier, of course, would have been trying to
get across the river wearing heavy equipment, heavy
dress, and, of course, maybe carrying
some heavy weapons. So you certainly couldn't
swim with all that kit on. So the bag would have
been there to provide him with the buoyancy to
get across the river. The mouthpiece would therefore
have been simply there to maintain the bag in
an inflated condition. NARRATOR: The experiment
illustrates that the bags were used for surface swimming
rather than underwater swimming. This tactic is still
used by special forces to swim distances with
heavy weapons today. HARRY SIDEBOTTOM: Of course, it
is completely incredible to us that the ancient world could
have had any underwater devices to explore the marine world. NARRATOR: But Richard is
not giving up in his quest to discover ancient
covert diving equipment. He is examining textual evidence
that claims the special forces of Alexander the Great conducted
covert underwater attacks. Alexander was born in Macedonia
in northern Greece in 356 BC. HARRY SIDEBOTTOM:
Alexander was universally considered in the ancient world
the greatest general that ever lived. He was a man who
led from the front, but also a man who took
brilliant tactical decisions. NARRATOR: Ancient accounts
dating from the 4th century BC tell of Alexander's siege
at the Phoenician city of Tire. They have given
birth to a legend. Alexander was said to have
examined the city's defenses by mounting an underwater
operation with a diving bell. RICHARD WINDLEY: The model we
have here is meant to represent a diving bell. It would seem to me that this
is probably the most likely and the most effective and
easiest way of getting divers to undertake these kind
of covert operations. NARRATOR: The concept of the
bell is relatively simple. Air trapped under the
dome provides a diver with an underwater reservoir
from which to breathe. PAUL HAYNES: We lower it down
to the bottom of the tank, approximately six meters depth. We provide a
sufficient length here to allow me to
swim in underneath and place my head and
shoulders within the bell area. NARRATOR: The air
trapped in the bell will cause the device to float. To stop it from
shooting to the surface, weights are attached to
ropes around the container. PAUL HAYNES: It's going to
be difficult to level it. NARRATOR: These weights provide
a downward force under gravity exactly equal to the upward
buoyancy force exerted on the bell by the trapped air. While Paul prepares
to dive again, technicians maneuver
the bell into the water. [music playing] The operation is complicated,
but finally, the bell sinks to the bottom. [music playing] While Richard watches
from the surface, Dr. Bevan observes from a
reinforced viewing window beneath the tank. With the bell on the bottom,
Paul fills his lungs and dives. Once at the tank floor,
Paul will perform two tests. The first investigates
whether he can move around using the bell
as a permanent air source. As he works, Paul is only
breathing the compressed air from the bell into his lungs. A second test investigates
whether Paul can make journeys into the open water and then
return to the bell for more air. But with only the compressed
air from the bell in his lungs, if he changes his depth,
the increase in pressure will cause his chest to explode. This is an exceptionally
dangerous operation. Paul relies on all his
training to keep himself at the exact depth of
the bell and alive. For this reason, he
must exhale continuously as he returns to the surface. PAUL HAYNES: Once you get
down there and get settled, I mean, the breathing
is quite comfortable. You've got good visibility and
can quite readily move around. You can use it as a stationary
sort of resupply of gas to-- to work from to do salvage
work, simple tasks. NARRATOR: Our
investigation proves that before the advent
of modern scuba gear, military engineers were capable
of designing technologies that allowed their special forces to
work at depth for long periods. DR. JOHN BEVAN: It's
extremely successful. It's exactly what I would have
expected in the real world, so to speak. The bell has been placed
on the seabed ready. It's got a full
charge of fresh air. The diver has gone down. He's made himself comfortable. He's been able to go out,
do his dive, do some work, and then come back to the
bell when he's comfortable. And so he's been able to work
away for quite a long time down there. NARRATOR: The tests
at the deep tank have revealed that the ancients,
two, even 3,000 years ago did not just master the seas,
but conquered its depths. Devices like the snorkel would
have allowed covert operations. DR. JOHN BEVAN: It functioned
the way it ought to. That is, the diver is
out of sight completely, and you've just got a part
of snorkel out of the water. And that's not so easy to see. NARRATOR: The Assyrian bladder,
while not as sophisticated as the high tech rebreathers
used by today's special forces' divers, did allow commandos
to carry heavy weapons across the water quickly
and more effectively. DR. JOHN BEVAN: They're
equivalent of a life jacket, a buoyancy aid, modern
buoyancy aid today. So it would keep you
well out of the water. If you couldn't swim very
well, it would keep you safe. And of course, if you've
got any heavy equipment, it'll keep you kind high in
the water again with buoyancy. NARRATOR: And
Alexander's bell has shown that even two and a
half thousand years ago, military engineers were capable
of designing technologies that allowed their special forces to
work at depth for long periods. These technologies were being
used by commandos millennia ago. And the principles and
tactics they initiated are still used in the
modern theater of war nearly 3,000 years later. MAN: The message
that comes home to me is just how amazingly
impressive and ambitious and technologically competent
these people were that were building these ancient vessels. NARRATOR: From technological
innovation and experimentation beneath the waves to the
super destroyers that cruised upon them, the ancient military
engineers were continuously pushing back the
boundaries of invention. And as modern military engineers
follow in their footsteps, they rely every day on the debt
they owe the naval inventors of the ancient world.
