October 14, 2019 • 48 mins
How do submarines work? When were they invented? In this episode, we explore the truths (and myths) about the origin of submarines.
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Episode Transcript
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Speaker 1 (00:04):
Welcome to Tech Stuff, a production of I Heart Radios,
How Stuff Works. Hey there, and welcome to tech Stuff.
I'm your host, Jonathan Strickland. I'm an executive producer with
I Heart Radio and How Stuff Works and a lot
of all things tech and over on Twitter, a listener
(00:26):
named Steve sent me a message asking me to do
an episode about submarines, and I was sure I had
done a full episode about submarines before, But then after
I searched the archives, the best I could find was
an episode I did with Scott Benjamin about personal submarines
that was more about the expensive and frankly dangerous toys
(00:50):
of people who have way more money than they have
self preservation instincts. So in this episode, I'm really going
to cover the history of submarines and how they work. Actually,
this is the first of a couple of episodes because
the history is pretty long, and while I could have
summarized the early history of submarines, I find that that
(01:10):
development is really fascinating. I mean, you think about what
it would take to risk everything by building a contraption
that can travel under the water where and you may
not know this, people can't normally breathe so we're gonna
look at the early history of submarines, not even getting
(01:31):
into the twentieth century in this episode. Spoiler alert. So
part of what makes this a fun topic to research
is that you really get to see when humans first
began to suss out why stuff floats or sinks. Archimedes
or Archie as I like to call him, wrote down
the earliest account of why this is at least the
(01:52):
earliest that we know of. There may have been earlier accounts,
but this is the one that we know about. He
described a force of a body partially submerged in a
fluid that would then push that body upward. And the
story goes that he figured this out while taking a bath,
that he figured out that this force that would hold
(02:12):
a body up in water. Uh, was something that came
to him while he was he himself was actually in water.
And one of the principles that describes this force, it's
called bullyancy. Essentially, it's saying that the amount of force
that is exerted on the submerged object is equal to
(02:34):
the weight of the water that the object is displacing. Now,
as a kid, I remember being a bit confused about
this concept because you take a look at stuff around you,
and you see what floats or sinks, and it it's
not always you know, uh, intuitive to a child, or,
if I'm going to be honest, to a young adult.
(02:55):
It took me a while to grasp this thing because
you know, like rocks sing in the water, right, rock sinks.
But then you have giant ships, like enormous, huge ships
that are clearly much heavier than rocks are, and those float. Now,
in my kid brain, I couldn't reconcile this. I mean,
clearly it had to be the weight of stuff that
(03:17):
determined whether or not it sank. Right, obviously, now that's
not correct, But it took a while before my brain
could wrap itself around the reasons why. So, the reason
is all about displacement water displacement. If the object displaces
enough water so that the weight of the water it
displaces is greater than the weight of the object, then
(03:41):
the object will float. If the object displaces too little
water so that the displaced water weighs less than the
weight of the object, then it will sink. And really
it comes down to density, not so much weight, but
really density. So if the density of the object is
less than that of water, it will float. If it
is greater than water, it will sink. And density and
(04:02):
mass are pretty easy to confuse. For goofballs like me.
Mass is how much stuff an object has. You know
how much stuff is to that particular thing. A chair
has a certain mass, but that's just part of an
object's physical features. You also have to take into account
the density, which is what you can think of as
(04:23):
the distribution of mass within an object. So a dense
object is going to have its mass packed in more
tightly than a less dense object of the same size.
So you have to think about the size, shape, and
mass of a thing before you'll know whether it will
displace enough water to keep it afloat. Our comedees actually
(04:43):
used water displacement to determine density as well. So the
basic formula for density is you take an objects mass
and you divide it by the objects volume, And you
would use scales to determine an object's mass, right, you
would have weights that you knew equalled out to a
specific amount of mass, like a kilogram weight, for example,
(05:04):
and you would weigh an object against that. But unless
the object is of a standard sort of shape, like
you know, a box, you might not have a neat
and nifty formula you could use to describe its volume.
You know, if it's an irregular shape, it's tricky. How
do you figure out the volume of an irregularly shaped object. Well,
you could use water, and that's because we know that
(05:26):
water behaves with displacement in a very consistent way under
specific conditions. So one millilet of water will occupy one
cubic centimeter of space. And this is specifically when water
is at standard conditions, which a standard temperature is zero
degrees celsius and standard pressure would be at one atmosphere.
(05:49):
And that's because we want to make sure we're using
standard conditions because you know, obviously water molecules will move
apart as you heat them up, so you'll get some
expansion and more air pressure adds compressive elements. Although to
be fair, water is extremely difficult to compress and that
would change the measurements slightly. So under standard conditions we
(06:15):
have this idea that water occupies one million leader or
one million eader of water. Rather we'll occupy one cubic
centimeter space. So an object completely submerged in water displaces
or offsets a volume of water equal to the volume
of the object. So if you put an object in
water at standard conditions and you have a little you know,
(06:38):
measuring stick there that lets you read how much water
has been displaced, and you see that the water has
been displaced by a hundred millilaters, that would mean that
the object you put in the water has a volume
of one hundred cubic centimeters. One million leader equals one
cubic centimeter. So then you would take the objects mass,
you would divide it by that one dred cubic center meters,
(07:00):
and that would tell you what the object's density is. Now,
water's density at twenty degrees celsius is one gram per
cubic centimeter, So if the object's density is less than that,
it will float. If it's greater than that, it'll sink.
This is why giant warships made out of metal can
cruise along the waves, and while they weigh a lot,
(07:23):
the water they displace has much greater density, so the
boats will stay afloat. But what if you designed a
vessel that could travel under the water, or better yet,
you designed the vessel that could have some sort of
control mechanism to allow it to either float or dive
under the water. On top of that, there's another pesky
(07:44):
problem to work out besides figuring out how to get
a vessel to go above or below the waves. Assuming
this vessel is also meant to hold people, there has
to be some sort of method for getting air to
the people inside, as we don't tend to funk action
too well if we can't breathe, So that also was
a problem that had to be solved now. Since ancient times,
(08:06):
we knew we could bring air down with us under water,
but that air would only last a short while before
the oxygen levels were too low to be useful and
we would asphyxiate. We didn't have a grasp on oxygen
and carbon dioxide just yet, but we did know that
you couldn't just keep breathing the same air indefinitely. Eventually
you would have exhausted all the breathable air and you
(08:29):
would need to resurface. Aristotle wrote about diving bells, which
are containers that could be lowered with the open side
of the container facing the floor of the ocean or
the lake or river or whatever, and they could be
dense enough to sink even with the added buoyancy of
the captured air inside the container, and water pressure would
(08:52):
keep the air from escaping the container, and he wrote, quote,
they enable the divers to respire equally well by letting
down a cauldron, for this does not fill with water,
but retains the air in the quote, So essentially a
diving bell. And that was way back in the fourth
century b c. But that was also before we had
(09:12):
susced out a way to replenish the air in the
diving bell. So while you could use it to go underwater,
you couldn't hang out for very long before you had
consumed all the breathable air and you needed to resurface.
So another problem is that water pressure that I just
talked about. It would compress the air inside a diving bell,
so the air would take up less space inside the bell,
(09:33):
and the bottom of the bell, assuming you're looking at
it with the bottom being the open side, would fill
a little bit with water. The water would come up
a little bit along the inside of the container, which
means you have a reduced work area as well a
reduced amount of useful area where you, as a person
could inhabit and still breathe. One way to fix that
(09:54):
would be to have a supply of pressurized air continue
to come down into the bell. But it would take
centuries to get that point. If you just included, say
a breathing tube from the bell to the surface, well
that wouldn't do any good at all. The water would
just go right up the bell and up the tube
a great deal. It's like if you put a straw
(10:16):
inside a glass of liquid. You know, unless you cap
the end of the straw, the liquid goes up the straw.
You don't have any way of pressurizing it to keep
the water from coming in. So you would have to
have this pressurized system and it would take hundreds of
years to get to that point. So when it comes
(10:36):
to getting really great details about the origin of submarines,
we hit some pretty big snags. There are reports about them,
but they aren't necessarily the most reliable. A lot of
them are second or third hand reports, and they don't
tend to have a whole lot of information about what
exactly happened or how it happened. But the general can
(11:00):
census is that a design for what would be the
first submarine that we have on record came from a
guy named William Bourne born was an English mathematician way
back in the sixteenth century, and the record of his
design dates to fifteen seventy eight, so just to give
you a little bit of context, at that time, England
(11:22):
was ruled by Queen Elizabeth the First and Shakespeare was
just fourteen years old. Born's design called for a totally
enclosed wooden boat, and then covering this wooden boat would
be oiled or greased leather that would help keep the
vessel water tight in order to reduce buoyancy. Borne's proposal
(11:43):
was to have hand cranked vices that connected to the
interior of the boat's hull. Now, in some descriptions that
I've read, it said that Borne intended to use the
vices to pull the sides in a little bit like
you're you're squeezing the boat from the in side, pulling
the inner walls inward and reducing the overall volume of
(12:05):
the boat, thus increasing your density. An illustration seems to
indicate that the idea was actually to have an inner
chamber inside this vessel, and that uh the inner chamber,
the innermost chamber where a person would be, would be waterproofed,
and then you would have space between this inner chamber
(12:27):
and these the hull or the outer sides of the boat,
So you would have this secondary chamber on either side
of the place where the operator would sit, and so
the visas would actually pull the boat's sections of whole
inward and allow those parts of the boat to be
flooded with water. So you're essentially pulling open almost like
(12:51):
a trap door. You're pulling in sides of the hull
of the boat. Water rushes in into a watertight section
that it surrounds the inner chamber where the operator sits,
and that would increase the density of the overall vessel.
That's what would allow you to sink beneath the waves.
(13:15):
If that's the case, I'm not sure what the plan
was to return buoyancy to the boat, because you would
need to have some way to purge the water out
of the space between the whole and the inner chamber
while sealing the boat closed. Again, you have to have
some way to force the water back out, otherwise you're
not gonna You're not going to decrease the density and
(13:36):
thus increase the buoyancy and be able to rise back
up above the waves. And maybe that's why Bourne never
made the darn thing as far as we can tell. Instead,
his design would remain an intriguing thought experiment for the
time being. Skip ahead of Monarch to the time of
James the First of England, and we do get to
what most people consider to be the first submarine. A
(13:59):
Dutch inventor named Cornelius van Drebble reportedly built a submarine,
which he called a diving boat in the early sixteen twenties.
Like Bourns proposed craft, Drebble's submarine was made of wood
and coated with greased leather. Propulsion came from ores that
extended out the sides of the vessel. These oars, you know,
(14:21):
the parts where the ore extended out from inside the boat.
Those had to be coated with flaps of leather to
create a waterproof seal, because otherwise they're going to get
water coming into your submarine. That's bad business. According to accounts,
it could dip as far as twelve or even fifteen
feet beneath the surface of the water, and Drebble demonstrate
(14:44):
the craft along the Thames River in London. Supposedly, even
Jimmy the King took a ride at one point. Now,
if Drebble made any detailed records of how this boat
actually worked, they have long since been lost. To time,
we're not entire really certain what mechanism he relied upon
to get the boat to go underwater. Some people have
(15:05):
suggested that the boat had some form of ballast barrels
or bladders that could be opened which would allow water
to come inside of them, increasing the overall density of
the boat, and this causing it to sink beneath the waves,
though I've not seen any description of how the vessel
would then expel the water to regain buoyancy. Uh. In
(15:26):
my just jettison the ballast, in which case then it
would rise up it's buoyancy would be returned. The earliest
records I can find of any kind of ballast system
actually comes two hundred years after this particular example. Others
suggest that perhaps the sloped shape of the bow that's
the front part of the boat acted as a sort
(15:48):
of reverse airplane wing, that when the boat began to
move forward, the slope would cause the water to flow
over the top of the boat, and that would push
the boat downward into the wall watter uh, And that
maybe with a system of weights could have added a
bit more downward force. I find that particular idea, the
idea of forward motion creating the downward force to allow
(16:12):
the boat to dive to be a little unlikely, simply
because I don't think you'd be able to go very
fast with oars. I don't think you could row fast
enough to make that downward motion, uh strong enough to
keep the boat underwater. You might bob a bit in
the Thames, but I don't think you would be able
(16:33):
to go twelve to fifteen feet beneath the surface. That's
just my own gut feeling there, because I don't think
you could get up the speed necessary to maintain that.
But we just don't really know for sure what the
mechanism was. Drebble made sure that the vessel had a
study supply of air by attaching to air hoses to
the boat, and the other ends of the hoses were
(16:56):
attached to floats that would drift on the surface of
the Thames above the boat. Now, I'm assuming that there
must have been some method of pumping the air down
into the boat, because otherwise you would have a problem. See,
carbon dioxide is denser than air, which means you need
a way to force breathable air down the hose to
(17:17):
the interior of the submarine. Otherwise it would become saturated
with C O two and you would eventually suffocate. This
was something an inventor named de Lorena, an Italian inventor,
had figured out way back in fift thirty five. He
made a diving bell with an apparatus that would replenish pressurized,
breathable air into the bell. Though he took the secret
(17:41):
of that invention to the grave. One other person reportedly
understood how it worked, but had sworn an oath never
to reveal it. So we don't know the precise methodology
used in that case either. Now, I'm sure it got
stuffy and humid inside Drebble's boat, but at least you
could get some air down there, and the crew wouldn't
(18:02):
automatically just die of asphyxiation. So the submarine as a working,
though primitive concept, dates back about five years, and I'm
sure it will come as a shock to learn that
since then we've made a few advancements. When we come back,
I'll talk a bit more about some of the earliest
subs and technology that made them work. But first let's
(18:23):
take a quick break. Okay, So, by the seventeen hundreds,
several inventors had experimented with different designs for submersible vehicles,
and they weren't really practical craft just yet, though the
(18:44):
potential military applications were immediately apparent. So this was during
the age when countries were imposing their will on others,
primarily through naval supremacy. Countries like Spain and England in
particular were known for doing this, and a common tactic
was to create a naval blockade around a port city
(19:05):
to prevent ships from leaving or arriving at that port city.
Creating a submersible that could secretly approach a blockade and
disrupt it, typically through the use of explosives that some
poor submarner would have to try and attach to those
boats was an obvious application for a submarine. It would
be an incredibly useful war tool. In se we get
(19:30):
the earliest published account of a ballast bladder, which some
unknown inventor suggested using bags made out of goat skin
to take in water so that submarine could dive below
the waves, and the bags would have a twisting rod
attached to them that would extend into the interior of
the submarine itself, so the submarner could grab all of
(19:52):
the rod and give it a good twist, and that
in turn would twist the ballast bag and that would
force water out of the ballast bag. It would have
a valve on the end of the bag so that
the water couldn't just come right back in, and that
would decrease the vessel's density and allow it to surface.
This was a predecessor for ballast tanks essentially do the
(20:13):
same thing, though you don't typically have to hand operate
them these days. A few decades later, we have the
first use of a submarine in war. That was the
American Revolutionary War. There was actually a submarine in the
American Revolutionary War. The submarine was called the Turtle. And
this was a pretty modest submarine. It's not like the
(20:36):
Red October or anything like that. It could hold precisely
one person. It was the design of David Bushnell, a
an engineering student who was studying at Yale at the time.
He and his brother Ezra built the dang Durn thing.
The Encyclopedia Britannica describes the shape of the submarine as
a quote walnut standing on end end to quote. And
(21:00):
if you see illustrations or the recreations of this particular submarine,
you'll see exactly what they mean. It does kind of
look like a sort of oval shaped submarine, large enough
to hold a single person on the inside. Facing forward
from the submarine, at least from the perspective of the pilot,
would be the propulsion system, which was a screw propeller
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and it worked on as similar principle as the Archimedes
screw pump, which was used to lift water from areas
of low elevation to areas of high elevation. The submarine
operator would crank a handle in order to turn this
screw propeller, which would effectively pull the submarine through the water,
and then with the other hand, the operator would control
(21:45):
a rudder that is in the back of the vessel
to provide the steering mechanism. The vessel also had a
secondary screw propeller, one that was oriented vertically, which meant
it was meant to help the submariner navigate critically through
the water, So if you were to dive beneath the waves,
you would use the vertical screw propeller to push you
(22:08):
down further into the water or to pull you up
to actually drive. The turtle had a chamber that would
be flooded with opening a valve, and that would just
decrease the ship's buoyancy, so it would start to sink
uh to surface. The operator could work some pumps inside
the turtle that would push this water back out of
(22:28):
that chamber. It also had ballast, both inside and attached
to the outside of the vessel that was used to
make sure the craft would maintain the proper orientation in
the water and not just you know, start flipping over
tilting to the side, which would be disastrous to the operator.
So the weights were really meant to make sure that
it maintained that up down orientation. Air came in through
(22:51):
a pair of snorkels, and the snoricles had lids that
would close whenever the vessel were to go underwater. Windows
on the hatch above the the operator would allow some
light to come into the interior of the vessel, although
it was meant primarily to be operated at night, and
(23:12):
the design also meant that if you went underwater, you
would have a limited supply of air because the snorkels
now would be closed, and you would also have much
less light to work from. The intent was to operate
so that only the hatch would be above the surface
of the water for most of a mission, so that
the operator would still be able to get a look
(23:33):
around seeing where they were in relation to a target.
They would also be able to breathe because the snorkels
would be exposed to the air, and then the operator
would only dive with the submarine in order to avoid
being seen or when it came time to actually attach
an explosive device to the target. To do that, the
(23:55):
ship had a drill that was also pointed up from
the top of a turtle, and this was to drill
a hole in a blockade ship, and then in that
hole the operator could attach a line for a gunpowder charge.
And this gunpowder charge was in the form of a
mine with an ingenious clockwork fuse mechanism, which I'll describe
(24:17):
in just a second. Now, Bushnell had already conducted experiments
while at Yale to find ways to make gunpowder explode underwater, which,
as I understand it, caused a bit of a stir
on campus. His mind was most likely a keg that
was about two and a half feet long or about
point seven six ms and one and a half feet
(24:38):
in diameter or point for six meters, and it could
hold about a hundred fifty pounds or about sixty eight
ms of gunpowder to create a timing mechanism for the explosive.
He actually worked with a pair of clockmakers. They were
known as a Phineas Pratt and Isaac Doolittle, And I
just want to say that I'm really loving these names
(24:59):
so far. Anyway, together Pratt, Doolittle and Bushnell came up
with a clockwork device that would trigger a flintlock mechanism.
It's the kind that you would find on a flint
lock musket, and the flintlock would have a piece of
flint and steel that would come together when the when
the mechanism activated, it would uh spring shut and that
(25:23):
would cause a spark. And the idea was that the
spark would then ignite a priming charge of gunpowder. The
priming charge would in turn ignite the explosive charge. So
the idea was that the sub operator would set a
timer on this device and attached the mind to a
ship using the hole that had been drilled into the
ship's hull, and then they would try and get the
(25:47):
heck out a dodge. They would be turning that hand
crank frantically to move the propeller in order to get
a safe distance away from the explosive. The team's mind
design would in theory give the operator enough time to
get the hack away from the exploding ship, and it
was a novel idea, but it turned out in practice
(26:09):
to fall short of expectations. The Turtles target was a
big one for its main mission. It was the HMS Eagle,
which happened to be the flagship of the British Admiral
Richard how As, the brother to General William how of
the British troops. But the Turtles drill turned out to
be incapable of cutting through the eagles copper plated hull.
(26:33):
By that time, dawn was breaking and the Turtles pilot,
a soldier named Ezra Lee, was in danger of being discovered.
So he attempted to sneak away, but he was spotted
and the Eagle let out a pursuit boat. Lee decided that, well,
the best thing for me to do is to set
(26:53):
the timer on this mine, because if they're gonna get me,
maybe they'll get the mind too and we'll all go
up together. So then he detached the mind from the Turtle,
and the mind did explode. It did not blow up
the pursuing boat, but it did scare them off, and
it gave him the opportunity to actually make an escape.
The Turtle would go on two more unsuccessful missions, one
(27:17):
of them under the operation of Phineas Pratt himself, but
nothing ever quite came of it, and the British eventually
sunk a ship that happened to be carrying the Turtle,
and the submarine was lost in that particular engagement. But
while the Turtle failed in its mission, the potential was obvious.
(27:37):
They just had to refine the technology. Moving ahead a
couple of decades, we come to Robert Fulton, an American
engineer and inventor who perhaps is best known. Maybe he's
most famously associated with steamboats, but in the early eight
hundreds he also developed an early submarine and was also
perhaps the most American of all classifications a capitalist. In fact,
(28:01):
you could call him an arms dealer. I'll explain. So
in seventeen seven, Fulton was living in France and he
goes to Paris and he pitches this idea for a
submarine that he calls the Nautilus. Jules Verne would take
note of this decade later, France and Britain have been
involved in a series of military conflicts for more than
(28:23):
a century. Uh In fact, some modern historians refer to
this as the Second hundred Years War. But the French
looked at Fulton's proposal and they said manon, because they
thought it was a dirty, underhanded way to fight a war.
Because this was a time when people thought war was
somehow better if everyone could see what everyone was doing
(28:44):
all the time, and sneaky stuff was considered to be
generally unfair. The mental gymnastics humans go through in order
to determine what is and isn't a fair way to
kill each other never really fails to confuse me. And
for the record, I'm pretty much against the whole killing
thing entirely, but I realized that the world we live
in makes that an impractical philosophy to be applied at
(29:07):
large in every situation. Anyway, Fulton appealed the decision and said, well, hey,
what about um, how about I build this sucker pretty
much on my own dime, and in return, if we
use it to attack British ships, you can pay me,
and that that payment will be based upon how big
the ship was, how many guns it carried, and for
(29:27):
British shipping vessels. You can give me a portion of
whatever you end up taking from those shipping vessels. And
the French minister said that cord, which means okay, because heck,
I mean the France wouldn't have to spend a single
franc on this, and they would only have to pay
out a portion of any spoils if the thing actually worked.
(29:50):
So by eight Fulton had the Nautilus ready to go
and he wanted to demonstrate its capabilities on the Sin,
the river that runs through Paris. And unlike the Turtle,
the Nautilus had an iron ribbed hull coated with copper sheets.
It also had a conning tower or con. Now, a
(30:10):
ship's con is a designated area. It's typically raised above
other areas, from which the commander of the ship can
control or con the ship by issuing commands to the crew.
Future submarines would incorporate the con within a structure on
the top side of the submarine called the sail or
the fin, until technological advancements would render such an arrangement unnecessary.
(30:35):
The Nautilus also had a collapsible mast and a sales
system so that it could deploy a fan sail very
similar to what would be found on a Chinese junk
ship at the time. This would allow the Nautilus to
operate more like a classic ship when it's surfaced. The
Nautilus was a cigar or tear drop shape, taking the
(30:56):
basic form that we would see used in a lot
of submarines moving forward. It was nearly seven meters long
and two meters wide. They had horizontal wings or planes
that were meant to aid in directing the ship's incline
or decline as it was moving through the water. A
section of the keel was a hollow chamber that could
(31:18):
be flooded to increase the ship's density so it could
dive under the water. Hand powered pumps could push the
water back out of the hull and thus returned the
buoyancy to the ship and allow it to rise back
up and and surface. Propulsion once again came in the
form of a hand cranked screw propeller, and Fulton claimed
that the ship could operate safely at a depth of
(31:41):
thirty feet or nine meters, although a lot of people
were skeptical of that. Also, whenever he was doing demonstrations
on the seine, he always made a point to go
in the same direction as the current of the river itself,
which gave the sense that this boat was actually able
to move much faster than it really could in normal conditions.
(32:03):
The attack mechanism on this particular submarine was a spike
with an eye in it, so you can think of
it like a giant sewing needle, but attached to the
eye was a cable, and attached the cable was a
mine an explosive, and the mind was designed to explode
upon coming into contact with an enemy ship's hull. Eventually,
(32:24):
Fulton realized that he never build up the speed and
forced necessary to penetrate a ship's hull with this spike,
and so he decided instead to use a towed explosive
device called a carcass. Now it turned out to be moot,
because when Fulton tried to use the Nautilus in a
real world setting, it just couldn't keep up with the
(32:46):
ships it was targeting. Ships could spot it and then
maneuver out of the way, and this Nautilus was so
slow it can never catch up. The French eventually canceled
all contracts with Fulton, who then did the incredibly American
thing that I mentioned earlier. He switched sides. He had
been marketing the submarine to the French to use against
(33:08):
the British, so then he turned around to the British
to sell them essentially the very same technology to be
used against the French. Robert Fulton, pioneering arms dealer. His
attempts at using the submarine for the British were just
as fruitless as they had been for the French, and
the Breads were able to dominate the seas with their
(33:29):
more conventional navy, and ultimately Fulton submarine would never see
a successful wartime use and he would scrap it, focusing
on steamboats instead. The next advances in submarines would arrive
before and during the Civil War in the United States.
I'll explain more in just a second, but first let's
take another quick break. In eighteen fifty five, a Bavarian
(33:59):
engineer named Wilhelm Bower built a submarine for Russia. It
was called the C Devil and it would require a
crew of about a dozen sailors. Rather than a hand
crank propeller, this submarine used a treadmill to provide the
power needed to drive the propeller's motion, with four sailors
providing the foot power to do so. Bauer had built
(34:22):
an earlier submarine back in Bavaria, but it had sunk
on a test run, and Bower and two other men
aboard had to actually wait while the vessel slowly filled
with water until it reached a point where the pressure
on the inside of the submarine had equalized enough to
open the hatch and swim out. Because the water pressure
(34:42):
outside the submarine was so great, they could not physically
open the hatch the water weight was too great. Once
the pressure equalized, they were able to open it. Can
you imagine sitting in a sunken submarine for hours waiting
for there to be enough water in the summer so
you can open up that hatch. It must have been terrifying.
(35:04):
For that reason, Bower, in his Sea Devil design, included
a primitive airlock so that the crew could escape if
such an event were to occur. With the new submarine,
the Sea Devil had more than one thirty successful dives,
including one during the coronation ceremony, in which the submarine
(35:24):
carried a four piece band which played beneath the water. Ultimately,
the Sea Devil would end up getting stuck in the
mud at the bottom of a river, reportedly because Russian admirals,
who had grown envious of Bower's success and his favor
with the Tsar, gave Bauer incorrect information about the depth
(35:45):
of the water, so, according to the story, they sabotaged
the effort. They said, oh, no, the river isn't that
you know. The river is is something like forty ft deep,
when in fact the river was twenty feet deep. So
then Bower dives further than what he actually can and
get stuck in the mud. During the American Civil War,
(36:06):
both the Union and the Confederacy experimented with submersible military boats.
The Union, for example, constructed a ship called the USS Alligator,
and the U. S. Navy gave the job of building
the Alligator to a firm called Nify and Levi, which
in turn was following the designs of a French engineer
named Brutus de Ville Roy or a de Ville Ras,
(36:30):
if you prefer. The purpose of the Alligator was to
counteract ironclad Confederate ships like the Merrimack. Now, this contract
called for a ship that was quote at least fifty
six inches in width and sixty six inches in height
and forty five feet in length, that equals out to
one point four meters wide, about one point seven ms high,
(36:53):
and about thirteen point seven ms long. The actual ship
would end up being a little different from those dimensions,
but you get the rough idea. The original propulsion system
of the Alligator was a set of ores that would
need to be operated by twenty two sailors. That ended
up being too slow and too crowded, so the Navy
scrapped that in favor of a screw type propeller, and
(37:16):
not only did that propeller provide a faster means of propulsion,
it also reduced the crew needed to operate the propulsion
system to just eight sailors instead of twenty two. The
submarine also had a diver lockout chamber, so again a
very primitive airlock system, and it also was said to
have an air purification system, but I couldn't find really
(37:40):
any information on how that actually worked, so I don't
really know what that was. You know, whether or not
it was fully self contained within the vessel, or it
was a system of hoses and pumps, I don't know. Ultimately,
the Alligator would be more of a headache and also
a sunken cost literal as it turned out more than
(38:02):
a viable military asset. It was being towed to South
Carolina for its first true military mission, but during that
trip bad weather struck and the towing ship had to
cut loose the submarine, which was unmanned at the time,
and the submarine ultimately sank beneath the waves and was lost.
(38:24):
The Confederacy built a semi submerged to torpedo ship called
the c. S. S. David. This was not a true submarine.
It could not dive beneath the water, but most of
the ship's body was beneath the water. It was steam powered, though,
which meant that it had to have a smoke stack
to exhaust the smoke from the coal that they were
(38:46):
burning in order to heat the boiler. And if you
have a smoke stack, it's got to stick out over
the water, so that part was always exposed to the air.
The ship was designed to hold four bowl three sailors
and a commanding officer. At the front end was a
long spar that had a torpedo at the very tip,
(39:09):
so this was a boat that was meant to ram
a ship, and the tip of the spar would explode
upon contact. The David attacked a Union ship called the
USS New Iron Sides on October Free while the David
struck New Iron Sides and the torpedo exploded as planned.
(39:29):
The resulting splash of water slashed into the David and
extinguished the fire for the ship's boiler, so now there
was no power to the ship anymore. The commanding officer
and one of the crew abandoned the ship. Technically, actually
two of the crew abandoned the ship. The third crew
member could not swim, so one of the other crew
(39:50):
members swam back, and then those two guys were actually
able to re light the boiler fire and then eventually
navigate away from the New irons Sides. Sailors aboard the
New Iron Sides had been firing with small arms to
against the David, but didn't do any significant damage. So uh,
those two guys got away. The other two were actually captured.
(40:14):
The most famous Confederate submarine was called the h L. Huntley,
which was named after Horace Huntley, who designed it. The
submarine used a spar torpedo similar to what the David
had used, but unlike the David, the Hunley could actually
dive beneath the water. It carried a crew of eight,
including the commanding officer. Sometimes some reports say could hold
(40:36):
up as as many as nine, but eight was the
standard crew and seven people were needed to hand crank
the propeller. The eighth wooden man a rudder to steer
the vessel. The vessel was nearly forty ft or twelve
meters long, and inside the height of the vessel was
just over four ft three inches or one point three meters,
(40:57):
which meant it was pretty cramped and said that submarine
you could not stand, you know, tall in there. The
ship had ballast tanks that could take on water and
also expel it using hand powered pumps. The ship also
carried weights to help act as ballast, and the weights
could be quickly jettisoned if the ship needed to surface quickly,
and it had a pair of snorkels that could bring
(41:19):
fresh air into the vessel when it was close to
the surface, Otherwise the ship was cut off from fresh air.
And according to some accounts, a single candle provided light
inside the submarine, and it also provided a warning when
the oxygen level was getting low because the candle's flame
would begin to flicker. Part of the reason why the
Hunley is famous is because it was responsible for a
(41:43):
couple of dozen deaths, most of them Confederate soldiers, and
remember this was a Confederate ship. During the testing of
the vessel, the Honley sank twice, the first result in
the loss of five crewmen, and in the second accident,
all eight of the crew died, including Hunley himself, who
was at the time acting as the commanding officer. Even
(42:05):
with those two accidents during the testing phase, the Confederacy
salvaged the ship, repaired it for use, and put it
back into official military use. On February seventeen sixty four,
the Hunley attacked the Union ship the Housatonic, which was
a wooden ship of war, and the Huntley's attack was
(42:25):
technically successful. The Housatonic did sink and five crew of
the Hausatonic died as a result. However, the Huntley itself
failed to return to port, and for many years no
one was really sure what had happened. I mean, clearly,
somewhere along the line the Hunley sank, but no one
was sure where or why. The Huntley, which was only
(42:48):
in thirty feet or nine meters of water, remained lost
until nineteen five years later. Crews were able to retrieve
the Huntley. Upon opening the submarine, the retrieval crews were
surprised to find that the Hunley's crew were all at
their stations, which suggested there was no effort to abandon ship.
(43:09):
There was no struggle to try and open the hatches
or anything like that, which raises the question what actually
killed the crew before the ship had been unsealed. The
general theory was that the crew had either suffocated or
they had drowned, but the submarine had no signs of
any damage that would have caused them to drown, So
(43:30):
the leading hypothesis now is that the shock wave from
the exploding torpedo actually killed the crew. A ruptured blood
vessels in their lungs and led to them becoming incapacitated
and then ultimately dying. However, we do not know for
sure what did it now. I'm going to conclude this
episode with the description of one other early submarine built
(43:52):
while the Union and Confederacy were both attempting to make
practical use of submarines of their own. This ship's name
was Le Planeur, and this was designed by a man
named Bourgeois in the late eighteen fifties. Actual construction began
in eighteen sixty and it took a couple of years
for it to be finished, And as far as I
(44:14):
can tell, it was the first submarine to use a
mechanical means of propulsion rather than relying directly on manpower.
The submarine carried containers of compressed air, and the air
served many purposes. It provided the power needed to drive
the propellers of the submarine. So you know, we released
the compressed air and it moves the mechanical elements that
(44:36):
actually make the propeller turn. So this was an air
powered vehicle, and the subs engine was an eighty horsepower engine.
The compressed air would also keep pressure inside the submarine
greater than it was outside the submarine, which was said
to be good to keep water from seeping into the vessel,
(44:56):
which for submarines is considered to be a bad thing.
Tanks used to hold the compressed air were quite large.
They needed to be to hold enough air to operate
the submarine for longer than just a few moments. That
meant that the size of the overall vessel had to
be quite big as well. It measured one hundred forty
feet long or nearly forty three meters far larger than
(45:19):
any submarine before it. It required a crew of twelve
sailors to man the ship, and the innovations were pretty important,
but the sub also had its share of drawbacks. One
of those was that initially relied on a series of
pipes and pistons inside the submarine that could move water
around to act as ballast and to help provide stability
(45:39):
as the ship was diving or where when it was climbing. Uh.
And it was made more difficult because of the ship's size. Right,
You've got a ship that's very long, and you get
a sort of lever effect. Right, a small change at
a pivot point would end up being a huge change
toward either end of the submarine. And unfortunately, the system
(46:00):
wasn't able to react very quickly to changes in the
ship's orientation, so a typical trip under the waves would
be pretty harrowing. The ship would dive and the systems
needed to correct its attitude in the water to level
it out, would very slowly kick in, and then the
ship would start to level out, but it would overcorrect
(46:22):
and then it would start to climb and the whole
cycle would start up again. Now the system would be
trying to correct for the change in attitude where now
it's it's tilted up instead of down, and the process
would keep going, so you had this see saw effect
in the water as you're riding on the submarine. It
could not maintain a level heading with zero buoyancy, and
(46:45):
so ultimately the project was scrapped because it was just
too risky. There needed to be more innovation in the
field to stabilize the submarine so that it wouldn't be
so unmanageable underwater. Now. In our next episode, will continue
down the path of history to explore how marine technology
advanced over time and how modern submarines work today. But
there's a lot more to cover that will probably skip
(47:07):
around a little bit because in some cases we're talking
about evolutionary changes where it's you know, important changes, important
significant innovations in submarine technology. But to cover every single
one would be pretty exhausting, so I'll probably lump them
together in sections. But that's for the next episode. If
(47:28):
you guys have suggestions for future episodes of tech Stuff,
send me a message. The email addresses tech Stuff at
how stuff works dot com. Dropped by our website that's
tech Stuff podcast dot com. You'll find links to where
we are on social media. You also find an archive
of all of our past episodes up there, and there's
a link to our online store, where every purchase you
(47:49):
make goes to help the show, and we greatly appreciate it,
and I will talk to you again really soon. Tech
Stuff is a production of I Heart Radio's How Stuff Works.
For more podcasts from I heart Radio, visit the i
heart Radio app, Apple Podcasts, or wherever you listen to
your favorite shows.
Welcome to Tech Stuff, a production of I Heart Radios,
How Stuff Works. Hey there, and welcome to tech Stuff.
I'm your host, Jonathan Strickland. I'm an executive producer with
I Heart Radio and How Stuff Works and a lot
of all things tech and over on Twitter, a listener
(00:26):
named Steve sent me a message asking me to do
an episode about submarines, and I was sure I had
done a full episode about submarines before, But then after
I searched the archives, the best I could find was
an episode I did with Scott Benjamin about personal submarines
that was more about the expensive and frankly dangerous toys
(00:50):
of people who have way more money than they have
self preservation instincts. So in this episode, I'm really going
to cover the history of submarines and how they work. Actually,
this is the first of a couple of episodes because
the history is pretty long, and while I could have
summarized the early history of submarines, I find that that
(01:10):
development is really fascinating. I mean, you think about what
it would take to risk everything by building a contraption
that can travel under the water where and you may
not know this, people can't normally breathe so we're gonna
look at the early history of submarines, not even getting
(01:31):
into the twentieth century in this episode. Spoiler alert. So
part of what makes this a fun topic to research
is that you really get to see when humans first
began to suss out why stuff floats or sinks. Archimedes
or Archie as I like to call him, wrote down
the earliest account of why this is at least the
(01:52):
earliest that we know of. There may have been earlier accounts,
but this is the one that we know about. He
described a force of a body partially submerged in a
fluid that would then push that body upward. And the
story goes that he figured this out while taking a bath,
that he figured out that this force that would hold
(02:12):
a body up in water. Uh, was something that came
to him while he was he himself was actually in water.
And one of the principles that describes this force, it's
called bullyancy. Essentially, it's saying that the amount of force
that is exerted on the submerged object is equal to
(02:34):
the weight of the water that the object is displacing. Now,
as a kid, I remember being a bit confused about
this concept because you take a look at stuff around you,
and you see what floats or sinks, and it it's
not always you know, uh, intuitive to a child, or,
if I'm going to be honest, to a young adult.
(02:55):
It took me a while to grasp this thing because
you know, like rocks sing in the water, right, rock sinks.
But then you have giant ships, like enormous, huge ships
that are clearly much heavier than rocks are, and those float. Now,
in my kid brain, I couldn't reconcile this. I mean,
clearly it had to be the weight of stuff that
(03:17):
determined whether or not it sank. Right, obviously, now that's
not correct, But it took a while before my brain
could wrap itself around the reasons why. So, the reason
is all about displacement water displacement. If the object displaces
enough water so that the weight of the water it
displaces is greater than the weight of the object, then
(03:41):
the object will float. If the object displaces too little
water so that the displaced water weighs less than the
weight of the object, then it will sink. And really
it comes down to density, not so much weight, but
really density. So if the density of the object is
less than that of water, it will float. If it
is greater than water, it will sink. And density and
(04:02):
mass are pretty easy to confuse. For goofballs like me.
Mass is how much stuff an object has. You know
how much stuff is to that particular thing. A chair
has a certain mass, but that's just part of an
object's physical features. You also have to take into account
the density, which is what you can think of as
(04:23):
the distribution of mass within an object. So a dense
object is going to have its mass packed in more
tightly than a less dense object of the same size.
So you have to think about the size, shape, and
mass of a thing before you'll know whether it will
displace enough water to keep it afloat. Our comedees actually
(04:43):
used water displacement to determine density as well. So the
basic formula for density is you take an objects mass
and you divide it by the objects volume, And you
would use scales to determine an object's mass, right, you
would have weights that you knew equalled out to a
specific amount of mass, like a kilogram weight, for example,
(05:04):
and you would weigh an object against that. But unless
the object is of a standard sort of shape, like
you know, a box, you might not have a neat
and nifty formula you could use to describe its volume.
You know, if it's an irregular shape, it's tricky. How
do you figure out the volume of an irregularly shaped object. Well,
you could use water, and that's because we know that
(05:26):
water behaves with displacement in a very consistent way under
specific conditions. So one millilet of water will occupy one
cubic centimeter of space. And this is specifically when water
is at standard conditions, which a standard temperature is zero
degrees celsius and standard pressure would be at one atmosphere.
(05:49):
And that's because we want to make sure we're using
standard conditions because you know, obviously water molecules will move
apart as you heat them up, so you'll get some
expansion and more air pressure adds compressive elements. Although to
be fair, water is extremely difficult to compress and that
would change the measurements slightly. So under standard conditions we
(06:15):
have this idea that water occupies one million leader or
one million eader of water. Rather we'll occupy one cubic
centimeter space. So an object completely submerged in water displaces
or offsets a volume of water equal to the volume
of the object. So if you put an object in
water at standard conditions and you have a little you know,
(06:38):
measuring stick there that lets you read how much water
has been displaced, and you see that the water has
been displaced by a hundred millilaters, that would mean that
the object you put in the water has a volume
of one hundred cubic centimeters. One million leader equals one
cubic centimeter. So then you would take the objects mass,
you would divide it by that one dred cubic center meters,
(07:00):
and that would tell you what the object's density is. Now,
water's density at twenty degrees celsius is one gram per
cubic centimeter, So if the object's density is less than that,
it will float. If it's greater than that, it'll sink.
This is why giant warships made out of metal can
cruise along the waves, and while they weigh a lot,
(07:23):
the water they displace has much greater density, so the
boats will stay afloat. But what if you designed a
vessel that could travel under the water, or better yet,
you designed the vessel that could have some sort of
control mechanism to allow it to either float or dive
under the water. On top of that, there's another pesky
(07:44):
problem to work out besides figuring out how to get
a vessel to go above or below the waves. Assuming
this vessel is also meant to hold people, there has
to be some sort of method for getting air to
the people inside, as we don't tend to funk action
too well if we can't breathe, So that also was
a problem that had to be solved now. Since ancient times,
(08:06):
we knew we could bring air down with us under water,
but that air would only last a short while before
the oxygen levels were too low to be useful and
we would asphyxiate. We didn't have a grasp on oxygen
and carbon dioxide just yet, but we did know that
you couldn't just keep breathing the same air indefinitely. Eventually
you would have exhausted all the breathable air and you
(08:29):
would need to resurface. Aristotle wrote about diving bells, which
are containers that could be lowered with the open side
of the container facing the floor of the ocean or
the lake or river or whatever, and they could be
dense enough to sink even with the added buoyancy of
the captured air inside the container, and water pressure would
(08:52):
keep the air from escaping the container, and he wrote, quote,
they enable the divers to respire equally well by letting
down a cauldron, for this does not fill with water,
but retains the air in the quote, So essentially a
diving bell. And that was way back in the fourth
century b c. But that was also before we had
(09:12):
susced out a way to replenish the air in the
diving bell. So while you could use it to go underwater,
you couldn't hang out for very long before you had
consumed all the breathable air and you needed to resurface.
So another problem is that water pressure that I just
talked about. It would compress the air inside a diving bell,
so the air would take up less space inside the bell,
(09:33):
and the bottom of the bell, assuming you're looking at
it with the bottom being the open side, would fill
a little bit with water. The water would come up
a little bit along the inside of the container, which
means you have a reduced work area as well a
reduced amount of useful area where you, as a person
could inhabit and still breathe. One way to fix that
(09:54):
would be to have a supply of pressurized air continue
to come down into the bell. But it would take
centuries to get that point. If you just included, say
a breathing tube from the bell to the surface, well
that wouldn't do any good at all. The water would
just go right up the bell and up the tube
a great deal. It's like if you put a straw
(10:16):
inside a glass of liquid. You know, unless you cap
the end of the straw, the liquid goes up the straw.
You don't have any way of pressurizing it to keep
the water from coming in. So you would have to
have this pressurized system and it would take hundreds of
years to get to that point. So when it comes
(10:36):
to getting really great details about the origin of submarines,
we hit some pretty big snags. There are reports about them,
but they aren't necessarily the most reliable. A lot of
them are second or third hand reports, and they don't
tend to have a whole lot of information about what
exactly happened or how it happened. But the general can
(11:00):
census is that a design for what would be the
first submarine that we have on record came from a
guy named William Bourne born was an English mathematician way
back in the sixteenth century, and the record of his
design dates to fifteen seventy eight, so just to give
you a little bit of context, at that time, England
(11:22):
was ruled by Queen Elizabeth the First and Shakespeare was
just fourteen years old. Born's design called for a totally
enclosed wooden boat, and then covering this wooden boat would
be oiled or greased leather that would help keep the
vessel water tight in order to reduce buoyancy. Borne's proposal
(11:43):
was to have hand cranked vices that connected to the
interior of the boat's hull. Now, in some descriptions that
I've read, it said that Borne intended to use the
vices to pull the sides in a little bit like
you're you're squeezing the boat from the in side, pulling
the inner walls inward and reducing the overall volume of
(12:05):
the boat, thus increasing your density. An illustration seems to
indicate that the idea was actually to have an inner
chamber inside this vessel, and that uh the inner chamber,
the innermost chamber where a person would be, would be waterproofed,
and then you would have space between this inner chamber
(12:27):
and these the hull or the outer sides of the boat,
So you would have this secondary chamber on either side
of the place where the operator would sit, and so
the visas would actually pull the boat's sections of whole
inward and allow those parts of the boat to be
flooded with water. So you're essentially pulling open almost like
(12:51):
a trap door. You're pulling in sides of the hull
of the boat. Water rushes in into a watertight section
that it surrounds the inner chamber where the operator sits,
and that would increase the density of the overall vessel.
That's what would allow you to sink beneath the waves.
(13:15):
If that's the case, I'm not sure what the plan
was to return buoyancy to the boat, because you would
need to have some way to purge the water out
of the space between the whole and the inner chamber
while sealing the boat closed. Again, you have to have
some way to force the water back out, otherwise you're
not gonna You're not going to decrease the density and
(13:36):
thus increase the buoyancy and be able to rise back
up above the waves. And maybe that's why Bourne never
made the darn thing as far as we can tell. Instead,
his design would remain an intriguing thought experiment for the
time being. Skip ahead of Monarch to the time of
James the First of England, and we do get to
what most people consider to be the first submarine. A
(13:59):
Dutch inventor named Cornelius van Drebble reportedly built a submarine,
which he called a diving boat in the early sixteen twenties.
Like Bourns proposed craft, Drebble's submarine was made of wood
and coated with greased leather. Propulsion came from ores that
extended out the sides of the vessel. These oars, you know,
(14:21):
the parts where the ore extended out from inside the boat.
Those had to be coated with flaps of leather to
create a waterproof seal, because otherwise they're going to get
water coming into your submarine. That's bad business. According to accounts,
it could dip as far as twelve or even fifteen
feet beneath the surface of the water, and Drebble demonstrate
(14:44):
the craft along the Thames River in London. Supposedly, even
Jimmy the King took a ride at one point. Now,
if Drebble made any detailed records of how this boat
actually worked, they have long since been lost. To time,
we're not entire really certain what mechanism he relied upon
to get the boat to go underwater. Some people have
(15:05):
suggested that the boat had some form of ballast barrels
or bladders that could be opened which would allow water
to come inside of them, increasing the overall density of
the boat, and this causing it to sink beneath the waves,
though I've not seen any description of how the vessel
would then expel the water to regain buoyancy. Uh. In
(15:26):
my just jettison the ballast, in which case then it
would rise up it's buoyancy would be returned. The earliest
records I can find of any kind of ballast system
actually comes two hundred years after this particular example. Others
suggest that perhaps the sloped shape of the bow that's
the front part of the boat acted as a sort
(15:48):
of reverse airplane wing, that when the boat began to
move forward, the slope would cause the water to flow
over the top of the boat, and that would push
the boat downward into the wall watter uh, And that
maybe with a system of weights could have added a
bit more downward force. I find that particular idea, the
idea of forward motion creating the downward force to allow
(16:12):
the boat to dive to be a little unlikely, simply
because I don't think you'd be able to go very
fast with oars. I don't think you could row fast
enough to make that downward motion, uh strong enough to
keep the boat underwater. You might bob a bit in
the Thames, but I don't think you would be able
(16:33):
to go twelve to fifteen feet beneath the surface. That's
just my own gut feeling there, because I don't think
you could get up the speed necessary to maintain that.
But we just don't really know for sure what the
mechanism was. Drebble made sure that the vessel had a
study supply of air by attaching to air hoses to
the boat, and the other ends of the hoses were
(16:56):
attached to floats that would drift on the surface of
the Thames above the boat. Now, I'm assuming that there
must have been some method of pumping the air down
into the boat, because otherwise you would have a problem. See,
carbon dioxide is denser than air, which means you need
a way to force breathable air down the hose to
(17:17):
the interior of the submarine. Otherwise it would become saturated
with C O two and you would eventually suffocate. This
was something an inventor named de Lorena, an Italian inventor,
had figured out way back in fift thirty five. He
made a diving bell with an apparatus that would replenish pressurized,
breathable air into the bell. Though he took the secret
(17:41):
of that invention to the grave. One other person reportedly
understood how it worked, but had sworn an oath never
to reveal it. So we don't know the precise methodology
used in that case either. Now, I'm sure it got
stuffy and humid inside Drebble's boat, but at least you
could get some air down there, and the crew wouldn't
(18:02):
automatically just die of asphyxiation. So the submarine as a working,
though primitive concept, dates back about five years, and I'm
sure it will come as a shock to learn that
since then we've made a few advancements. When we come back,
I'll talk a bit more about some of the earliest
subs and technology that made them work. But first let's
(18:23):
take a quick break. Okay, So, by the seventeen hundreds,
several inventors had experimented with different designs for submersible vehicles,
and they weren't really practical craft just yet, though the
(18:44):
potential military applications were immediately apparent. So this was during
the age when countries were imposing their will on others,
primarily through naval supremacy. Countries like Spain and England in
particular were known for doing this, and a common tactic
was to create a naval blockade around a port city
(19:05):
to prevent ships from leaving or arriving at that port city.
Creating a submersible that could secretly approach a blockade and
disrupt it, typically through the use of explosives that some
poor submarner would have to try and attach to those
boats was an obvious application for a submarine. It would
be an incredibly useful war tool. In se we get
(19:30):
the earliest published account of a ballast bladder, which some
unknown inventor suggested using bags made out of goat skin
to take in water so that submarine could dive below
the waves, and the bags would have a twisting rod
attached to them that would extend into the interior of
the submarine itself, so the submarner could grab all of
(19:52):
the rod and give it a good twist, and that
in turn would twist the ballast bag and that would
force water out of the ballast bag. It would have
a valve on the end of the bag so that
the water couldn't just come right back in, and that
would decrease the vessel's density and allow it to surface.
This was a predecessor for ballast tanks essentially do the
(20:13):
same thing, though you don't typically have to hand operate
them these days. A few decades later, we have the
first use of a submarine in war. That was the
American Revolutionary War. There was actually a submarine in the
American Revolutionary War. The submarine was called the Turtle. And
this was a pretty modest submarine. It's not like the
(20:36):
Red October or anything like that. It could hold precisely
one person. It was the design of David Bushnell, a
an engineering student who was studying at Yale at the time.
He and his brother Ezra built the dang Durn thing.
The Encyclopedia Britannica describes the shape of the submarine as
a quote walnut standing on end end to quote. And
(21:00):
if you see illustrations or the recreations of this particular submarine,
you'll see exactly what they mean. It does kind of
look like a sort of oval shaped submarine, large enough
to hold a single person on the inside. Facing forward
from the submarine, at least from the perspective of the pilot,
would be the propulsion system, which was a screw propeller
(21:22):
and it worked on as similar principle as the Archimedes
screw pump, which was used to lift water from areas
of low elevation to areas of high elevation. The submarine
operator would crank a handle in order to turn this
screw propeller, which would effectively pull the submarine through the water,
and then with the other hand, the operator would control
(21:45):
a rudder that is in the back of the vessel
to provide the steering mechanism. The vessel also had a
secondary screw propeller, one that was oriented vertically, which meant
it was meant to help the submariner navigate critically through
the water, So if you were to dive beneath the waves,
you would use the vertical screw propeller to push you
(22:08):
down further into the water or to pull you up
to actually drive. The turtle had a chamber that would
be flooded with opening a valve, and that would just
decrease the ship's buoyancy, so it would start to sink
uh to surface. The operator could work some pumps inside
the turtle that would push this water back out of
(22:28):
that chamber. It also had ballast, both inside and attached
to the outside of the vessel that was used to
make sure the craft would maintain the proper orientation in
the water and not just you know, start flipping over
tilting to the side, which would be disastrous to the operator.
So the weights were really meant to make sure that
it maintained that up down orientation. Air came in through
(22:51):
a pair of snorkels, and the snoricles had lids that
would close whenever the vessel were to go underwater. Windows
on the hatch above the the operator would allow some
light to come into the interior of the vessel, although
it was meant primarily to be operated at night, and
(23:12):
the design also meant that if you went underwater, you
would have a limited supply of air because the snorkels
now would be closed, and you would also have much
less light to work from. The intent was to operate
so that only the hatch would be above the surface
of the water for most of a mission, so that
the operator would still be able to get a look
(23:33):
around seeing where they were in relation to a target.
They would also be able to breathe because the snorkels
would be exposed to the air, and then the operator
would only dive with the submarine in order to avoid
being seen or when it came time to actually attach
an explosive device to the target. To do that, the
(23:55):
ship had a drill that was also pointed up from
the top of a turtle, and this was to drill
a hole in a blockade ship, and then in that
hole the operator could attach a line for a gunpowder charge.
And this gunpowder charge was in the form of a
mine with an ingenious clockwork fuse mechanism, which I'll describe
(24:17):
in just a second. Now, Bushnell had already conducted experiments
while at Yale to find ways to make gunpowder explode underwater, which,
as I understand it, caused a bit of a stir
on campus. His mind was most likely a keg that
was about two and a half feet long or about
point seven six ms and one and a half feet
(24:38):
in diameter or point for six meters, and it could
hold about a hundred fifty pounds or about sixty eight
ms of gunpowder to create a timing mechanism for the explosive.
He actually worked with a pair of clockmakers. They were
known as a Phineas Pratt and Isaac Doolittle, And I
just want to say that I'm really loving these names
(24:59):
so far. Anyway, together Pratt, Doolittle and Bushnell came up
with a clockwork device that would trigger a flintlock mechanism.
It's the kind that you would find on a flint
lock musket, and the flintlock would have a piece of
flint and steel that would come together when the when
the mechanism activated, it would uh spring shut and that
(25:23):
would cause a spark. And the idea was that the
spark would then ignite a priming charge of gunpowder. The
priming charge would in turn ignite the explosive charge. So
the idea was that the sub operator would set a
timer on this device and attached the mind to a
ship using the hole that had been drilled into the
ship's hull, and then they would try and get the
(25:47):
heck out a dodge. They would be turning that hand
crank frantically to move the propeller in order to get
a safe distance away from the explosive. The team's mind
design would in theory give the operator enough time to
get the hack away from the exploding ship, and it
was a novel idea, but it turned out in practice
(26:09):
to fall short of expectations. The Turtles target was a
big one for its main mission. It was the HMS Eagle,
which happened to be the flagship of the British Admiral
Richard how As, the brother to General William how of
the British troops. But the Turtles drill turned out to
be incapable of cutting through the eagles copper plated hull.
(26:33):
By that time, dawn was breaking and the Turtles pilot,
a soldier named Ezra Lee, was in danger of being discovered.
So he attempted to sneak away, but he was spotted
and the Eagle let out a pursuit boat. Lee decided that, well,
the best thing for me to do is to set
(26:53):
the timer on this mine, because if they're gonna get me,
maybe they'll get the mind too and we'll all go
up together. So then he detached the mind from the Turtle,
and the mind did explode. It did not blow up
the pursuing boat, but it did scare them off, and
it gave him the opportunity to actually make an escape.
The Turtle would go on two more unsuccessful missions, one
(27:17):
of them under the operation of Phineas Pratt himself, but
nothing ever quite came of it, and the British eventually
sunk a ship that happened to be carrying the Turtle,
and the submarine was lost in that particular engagement. But
while the Turtle failed in its mission, the potential was obvious.
(27:37):
They just had to refine the technology. Moving ahead a
couple of decades, we come to Robert Fulton, an American
engineer and inventor who perhaps is best known. Maybe he's
most famously associated with steamboats, but in the early eight
hundreds he also developed an early submarine and was also
perhaps the most American of all classifications a capitalist. In fact,
(28:01):
you could call him an arms dealer. I'll explain. So
in seventeen seven, Fulton was living in France and he
goes to Paris and he pitches this idea for a
submarine that he calls the Nautilus. Jules Verne would take
note of this decade later, France and Britain have been
involved in a series of military conflicts for more than
(28:23):
a century. Uh In fact, some modern historians refer to
this as the Second hundred Years War. But the French
looked at Fulton's proposal and they said manon, because they
thought it was a dirty, underhanded way to fight a war.
Because this was a time when people thought war was
somehow better if everyone could see what everyone was doing
(28:44):
all the time, and sneaky stuff was considered to be
generally unfair. The mental gymnastics humans go through in order
to determine what is and isn't a fair way to
kill each other never really fails to confuse me. And
for the record, I'm pretty much against the whole killing
thing entirely, but I realized that the world we live
in makes that an impractical philosophy to be applied at
(29:07):
large in every situation. Anyway, Fulton appealed the decision and said, well, hey,
what about um, how about I build this sucker pretty
much on my own dime, and in return, if we
use it to attack British ships, you can pay me,
and that that payment will be based upon how big
the ship was, how many guns it carried, and for
(29:27):
British shipping vessels. You can give me a portion of
whatever you end up taking from those shipping vessels. And
the French minister said that cord, which means okay, because heck,
I mean the France wouldn't have to spend a single
franc on this, and they would only have to pay
out a portion of any spoils if the thing actually worked.
(29:50):
So by eight Fulton had the Nautilus ready to go
and he wanted to demonstrate its capabilities on the Sin,
the river that runs through Paris. And unlike the Turtle,
the Nautilus had an iron ribbed hull coated with copper sheets.
It also had a conning tower or con. Now, a
(30:10):
ship's con is a designated area. It's typically raised above
other areas, from which the commander of the ship can
control or con the ship by issuing commands to the crew.
Future submarines would incorporate the con within a structure on
the top side of the submarine called the sail or
the fin, until technological advancements would render such an arrangement unnecessary.
(30:35):
The Nautilus also had a collapsible mast and a sales
system so that it could deploy a fan sail very
similar to what would be found on a Chinese junk
ship at the time. This would allow the Nautilus to
operate more like a classic ship when it's surfaced. The
Nautilus was a cigar or tear drop shape, taking the
(30:56):
basic form that we would see used in a lot
of submarines moving forward. It was nearly seven meters long
and two meters wide. They had horizontal wings or planes
that were meant to aid in directing the ship's incline
or decline as it was moving through the water. A
section of the keel was a hollow chamber that could
(31:18):
be flooded to increase the ship's density so it could
dive under the water. Hand powered pumps could push the
water back out of the hull and thus returned the
buoyancy to the ship and allow it to rise back
up and and surface. Propulsion once again came in the
form of a hand cranked screw propeller, and Fulton claimed
that the ship could operate safely at a depth of
(31:41):
thirty feet or nine meters, although a lot of people
were skeptical of that. Also, whenever he was doing demonstrations
on the seine, he always made a point to go
in the same direction as the current of the river itself,
which gave the sense that this boat was actually able
to move much faster than it really could in normal conditions.
(32:03):
The attack mechanism on this particular submarine was a spike
with an eye in it, so you can think of
it like a giant sewing needle, but attached to the
eye was a cable, and attached the cable was a
mine an explosive, and the mind was designed to explode
upon coming into contact with an enemy ship's hull. Eventually,
(32:24):
Fulton realized that he never build up the speed and
forced necessary to penetrate a ship's hull with this spike,
and so he decided instead to use a towed explosive
device called a carcass. Now it turned out to be moot,
because when Fulton tried to use the Nautilus in a
real world setting, it just couldn't keep up with the
(32:46):
ships it was targeting. Ships could spot it and then
maneuver out of the way, and this Nautilus was so
slow it can never catch up. The French eventually canceled
all contracts with Fulton, who then did the incredibly American
thing that I mentioned earlier. He switched sides. He had
been marketing the submarine to the French to use against
(33:08):
the British, so then he turned around to the British
to sell them essentially the very same technology to be
used against the French. Robert Fulton, pioneering arms dealer. His
attempts at using the submarine for the British were just
as fruitless as they had been for the French, and
the Breads were able to dominate the seas with their
(33:29):
more conventional navy, and ultimately Fulton submarine would never see
a successful wartime use and he would scrap it, focusing
on steamboats instead. The next advances in submarines would arrive
before and during the Civil War in the United States.
I'll explain more in just a second, but first let's
take another quick break. In eighteen fifty five, a Bavarian
(33:59):
engineer named Wilhelm Bower built a submarine for Russia. It
was called the C Devil and it would require a
crew of about a dozen sailors. Rather than a hand
crank propeller, this submarine used a treadmill to provide the
power needed to drive the propeller's motion, with four sailors
providing the foot power to do so. Bauer had built
(34:22):
an earlier submarine back in Bavaria, but it had sunk
on a test run, and Bower and two other men
aboard had to actually wait while the vessel slowly filled
with water until it reached a point where the pressure
on the inside of the submarine had equalized enough to
open the hatch and swim out. Because the water pressure
(34:42):
outside the submarine was so great, they could not physically
open the hatch the water weight was too great. Once
the pressure equalized, they were able to open it. Can
you imagine sitting in a sunken submarine for hours waiting
for there to be enough water in the summer so
you can open up that hatch. It must have been terrifying.
(35:04):
For that reason, Bower, in his Sea Devil design, included
a primitive airlock so that the crew could escape if
such an event were to occur. With the new submarine,
the Sea Devil had more than one thirty successful dives,
including one during the coronation ceremony, in which the submarine
(35:24):
carried a four piece band which played beneath the water. Ultimately,
the Sea Devil would end up getting stuck in the
mud at the bottom of a river, reportedly because Russian admirals,
who had grown envious of Bower's success and his favor
with the Tsar, gave Bauer incorrect information about the depth
(35:45):
of the water, so, according to the story, they sabotaged
the effort. They said, oh, no, the river isn't that
you know. The river is is something like forty ft deep,
when in fact the river was twenty feet deep. So
then Bower dives further than what he actually can and
get stuck in the mud. During the American Civil War,
(36:06):
both the Union and the Confederacy experimented with submersible military boats.
The Union, for example, constructed a ship called the USS Alligator,
and the U. S. Navy gave the job of building
the Alligator to a firm called Nify and Levi, which
in turn was following the designs of a French engineer
named Brutus de Ville Roy or a de Ville Ras,
(36:30):
if you prefer. The purpose of the Alligator was to
counteract ironclad Confederate ships like the Merrimack. Now, this contract
called for a ship that was quote at least fifty
six inches in width and sixty six inches in height
and forty five feet in length, that equals out to
one point four meters wide, about one point seven ms high,
(36:53):
and about thirteen point seven ms long. The actual ship
would end up being a little different from those dimensions,
but you get the rough idea. The original propulsion system
of the Alligator was a set of ores that would
need to be operated by twenty two sailors. That ended
up being too slow and too crowded, so the Navy
scrapped that in favor of a screw type propeller, and
(37:16):
not only did that propeller provide a faster means of propulsion,
it also reduced the crew needed to operate the propulsion
system to just eight sailors instead of twenty two. The
submarine also had a diver lockout chamber, so again a
very primitive airlock system, and it also was said to
have an air purification system, but I couldn't find really
(37:40):
any information on how that actually worked, so I don't
really know what that was. You know, whether or not
it was fully self contained within the vessel, or it
was a system of hoses and pumps, I don't know. Ultimately,
the Alligator would be more of a headache and also
a sunken cost literal as it turned out more than
(38:02):
a viable military asset. It was being towed to South
Carolina for its first true military mission, but during that
trip bad weather struck and the towing ship had to
cut loose the submarine, which was unmanned at the time,
and the submarine ultimately sank beneath the waves and was lost.
(38:24):
The Confederacy built a semi submerged to torpedo ship called
the c. S. S. David. This was not a true submarine.
It could not dive beneath the water, but most of
the ship's body was beneath the water. It was steam powered, though,
which meant that it had to have a smoke stack
to exhaust the smoke from the coal that they were
(38:46):
burning in order to heat the boiler. And if you
have a smoke stack, it's got to stick out over
the water, so that part was always exposed to the air.
The ship was designed to hold four bowl three sailors
and a commanding officer. At the front end was a
long spar that had a torpedo at the very tip,
(39:09):
so this was a boat that was meant to ram
a ship, and the tip of the spar would explode
upon contact. The David attacked a Union ship called the
USS New Iron Sides on October Free while the David
struck New Iron Sides and the torpedo exploded as planned.
(39:29):
The resulting splash of water slashed into the David and
extinguished the fire for the ship's boiler, so now there
was no power to the ship anymore. The commanding officer
and one of the crew abandoned the ship. Technically, actually
two of the crew abandoned the ship. The third crew
member could not swim, so one of the other crew
(39:50):
members swam back, and then those two guys were actually
able to re light the boiler fire and then eventually
navigate away from the New irons Sides. Sailors aboard the
New Iron Sides had been firing with small arms to
against the David, but didn't do any significant damage. So uh,
those two guys got away. The other two were actually captured.
(40:14):
The most famous Confederate submarine was called the h L. Huntley,
which was named after Horace Huntley, who designed it. The
submarine used a spar torpedo similar to what the David
had used, but unlike the David, the Hunley could actually
dive beneath the water. It carried a crew of eight,
including the commanding officer. Sometimes some reports say could hold
(40:36):
up as as many as nine, but eight was the
standard crew and seven people were needed to hand crank
the propeller. The eighth wooden man a rudder to steer
the vessel. The vessel was nearly forty ft or twelve
meters long, and inside the height of the vessel was
just over four ft three inches or one point three meters,
(40:57):
which meant it was pretty cramped and said that submarine
you could not stand, you know, tall in there. The
ship had ballast tanks that could take on water and
also expel it using hand powered pumps. The ship also
carried weights to help act as ballast, and the weights
could be quickly jettisoned if the ship needed to surface quickly,
and it had a pair of snorkels that could bring
(41:19):
fresh air into the vessel when it was close to
the surface, Otherwise the ship was cut off from fresh air.
And according to some accounts, a single candle provided light
inside the submarine, and it also provided a warning when
the oxygen level was getting low because the candle's flame
would begin to flicker. Part of the reason why the
Hunley is famous is because it was responsible for a
(41:43):
couple of dozen deaths, most of them Confederate soldiers, and
remember this was a Confederate ship. During the testing of
the vessel, the Honley sank twice, the first result in
the loss of five crewmen, and in the second accident,
all eight of the crew died, including Hunley himself, who
was at the time acting as the commanding officer. Even
(42:05):
with those two accidents during the testing phase, the Confederacy
salvaged the ship, repaired it for use, and put it
back into official military use. On February seventeen sixty four,
the Hunley attacked the Union ship the Housatonic, which was
a wooden ship of war, and the Huntley's attack was
(42:25):
technically successful. The Housatonic did sink and five crew of
the Hausatonic died as a result. However, the Huntley itself
failed to return to port, and for many years no
one was really sure what had happened. I mean, clearly,
somewhere along the line the Hunley sank, but no one
was sure where or why. The Huntley, which was only
(42:48):
in thirty feet or nine meters of water, remained lost
until nineteen five years later. Crews were able to retrieve
the Huntley. Upon opening the submarine, the retrieval crews were
surprised to find that the Hunley's crew were all at
their stations, which suggested there was no effort to abandon ship.
(43:09):
There was no struggle to try and open the hatches
or anything like that, which raises the question what actually
killed the crew before the ship had been unsealed. The
general theory was that the crew had either suffocated or
they had drowned, but the submarine had no signs of
any damage that would have caused them to drown, So
(43:30):
the leading hypothesis now is that the shock wave from
the exploding torpedo actually killed the crew. A ruptured blood
vessels in their lungs and led to them becoming incapacitated
and then ultimately dying. However, we do not know for
sure what did it now. I'm going to conclude this
episode with the description of one other early submarine built
(43:52):
while the Union and Confederacy were both attempting to make
practical use of submarines of their own. This ship's name
was Le Planeur, and this was designed by a man
named Bourgeois in the late eighteen fifties. Actual construction began
in eighteen sixty and it took a couple of years
for it to be finished, And as far as I
(44:14):
can tell, it was the first submarine to use a
mechanical means of propulsion rather than relying directly on manpower.
The submarine carried containers of compressed air, and the air
served many purposes. It provided the power needed to drive
the propellers of the submarine. So you know, we released
the compressed air and it moves the mechanical elements that
(44:36):
actually make the propeller turn. So this was an air
powered vehicle, and the subs engine was an eighty horsepower engine.
The compressed air would also keep pressure inside the submarine
greater than it was outside the submarine, which was said
to be good to keep water from seeping into the vessel,
(44:56):
which for submarines is considered to be a bad thing.
Tanks used to hold the compressed air were quite large.
They needed to be to hold enough air to operate
the submarine for longer than just a few moments. That
meant that the size of the overall vessel had to
be quite big as well. It measured one hundred forty
feet long or nearly forty three meters far larger than
(45:19):
any submarine before it. It required a crew of twelve
sailors to man the ship, and the innovations were pretty important,
but the sub also had its share of drawbacks. One
of those was that initially relied on a series of
pipes and pistons inside the submarine that could move water
around to act as ballast and to help provide stability
(45:39):
as the ship was diving or where when it was climbing. Uh.
And it was made more difficult because of the ship's size. Right,
You've got a ship that's very long, and you get
a sort of lever effect. Right, a small change at
a pivot point would end up being a huge change
toward either end of the submarine. And unfortunately, the system
(46:00):
wasn't able to react very quickly to changes in the
ship's orientation, so a typical trip under the waves would
be pretty harrowing. The ship would dive and the systems
needed to correct its attitude in the water to level
it out, would very slowly kick in, and then the
ship would start to level out, but it would overcorrect
(46:22):
and then it would start to climb and the whole
cycle would start up again. Now the system would be
trying to correct for the change in attitude where now
it's it's tilted up instead of down, and the process
would keep going, so you had this see saw effect
in the water as you're riding on the submarine. It
could not maintain a level heading with zero buoyancy, and
(46:45):
so ultimately the project was scrapped because it was just
too risky. There needed to be more innovation in the
field to stabilize the submarine so that it wouldn't be
so unmanageable underwater. Now. In our next episode, will continue
down the path of history to explore how marine technology
advanced over time and how modern submarines work today. But
there's a lot more to cover that will probably skip
(47:07):
around a little bit because in some cases we're talking
about evolutionary changes where it's you know, important changes, important
significant innovations in submarine technology. But to cover every single
one would be pretty exhausting, so I'll probably lump them
together in sections. But that's for the next episode. If
(47:28):
you guys have suggestions for future episodes of tech Stuff,
send me a message. The email addresses tech Stuff at
how stuff works dot com. Dropped by our website that's
tech Stuff podcast dot com. You'll find links to where
we are on social media. You also find an archive
of all of our past episodes up there, and there's
a link to our online store, where every purchase you
(47:49):
make goes to help the show, and we greatly appreciate it,
and I will talk to you again really soon. Tech
Stuff is a production of I Heart Radio's How Stuff Works.
For more podcasts from I heart Radio, visit the i
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Karah Preiss
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