The Modern Submarine

How did the modern submarine develop? What kind of technology is on a submarine? How do they navigate? 

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Episode Transcript

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
How Stuff Works in iHeart Radio and I love all
things tech. And today we're going to continue our journey
to the button of the Ocean, or at least our

(00:26):
our journey to understanding submarines and how they work. So
in our previous episode, I talked about the early attempts
at building vehicles that can travel beneath the waves, and
we learned about brave or perhaps fool hardy inventors who
took great risks and sometimes perished in the process to
come up with a working submarine. And nearly all the

(00:49):
applications for the innovation were centered around warfare. There are
a couple of people who are thinking about it for
you know, like a pleasure cruise under the waters. But
for the most part, people are thinking, how can I
use this to sneak up on people I don't like
and then blow them up real good? Now. I left
off in the middle of the nineteenth century with a

(01:10):
discussion on the submarines that were used during the Civil
War as well as one that was built around that
same time over in France. So let's pick up from there.
And as I mentioned in that episode, I'll not be
covering every single submarine or every single advance in submarines
bit by bit, because that would take forever. We'd have

(01:31):
to do fifty episodes. So we're going to be jumping
around a little bit in this one. One innovation that
isn't about submarines specifically would still contribute to their evolution,
and that was the self propelled torpedo. In eighteen sixty eight,
a man named Robert Whitehead came up with a design

(01:51):
for an explosive device that could travel through the water
using compressed air as the power source. Now keep in
mind that up until all that point, submarines relied on
either approaching a ship close enough so that you could
physically attach an explosive mind to that ship, or having
a spar mounted to the front of the submarine and

(02:14):
then ramming a ship and the spar is tipped with
an explosive, which clearly would put both the ship and
the submarine at risk. That's how, in fact, the Hunley
sank after it hit its target, the Hausatanic. But in
that process, everyone on board the Huntley died. That's not
ideal either. There was also the attempt to tow an

(02:38):
explosive behind the submarine in an effort to set it
on a course that would collide with the target ship.
But that was also dangerous because if it collided with
a submarine blow up prematurely. So the development of a
projectile that could travel through the water would mean it
would be possible to design a submarine that could be
an effective military vehicle. You would have a torpedo tube

(03:00):
that you could load a torpedo into. You would flood
the tube and then you would activate the torpedo. If
such a vessel could carry torpedoes like the ones that
white Head was designing, then they could launch them at
a target at a distance without putting itself in direct danger.
Whitehead's torpedo design called for a pair of cylinders containing

(03:20):
compressed air at ninety atmospheres, and these were within the
body of the torpedo itself, took up most of the
space inside the torpedo. In fact, the compressed air would,
when released, force its way outward, turning mechanical components through
a system of gears that transferred that motion to propellers
at the base or the rear of the torpedo. There

(03:42):
was also a rudder in the back that allowed for
stability and some aiming capabilities. There's no real way to
steer a torpedo once it left, not yet anyway. Whitehead's
prototype could travel at a speed of six and a
half knots that's about seven and a half miles per
hour or twelve kilometers per hour, and it had a
range of around two hundred yards or about a hundred

(04:03):
eighty three ms. A ship, you know, the the over
the waves kind of ship, was meant to launch it
from a tube that was at or below the waterline,
using either a gunpowder charge or compressed air. Whitehead and
others would improve on that basic design, adding components like
gyroscopes to help with steering and stability, but all that

(04:23):
would happen over the course of the next few decades. Now,
the military submarines I covered in the last episode were
at best only partially successful, but there was a lot
of work that needed to be done to make them
a more reliable resource. Much of that work would be
done by an inventor named John Philip Holland, who many
call the Father of the modern submarine. Holland was born

(04:47):
not in Holland but in Ireland, which I think he
did as a joke to confuse me. He went to
school in Limerick, so I guess this is happening. Get
ready for some poetry. M M. John Philip was quite
the boy wonder who flinched, not at high waves or
at thunder. I don't care a pip. I built a

(05:09):
new ship. I don't float on the sea. I go under.
There's your Limerick. He studied engineering and worked on many hypotheses,
including a paper about the possibilities of mechanical flight, and
this would be years before the Right Brothers found success
at Kitty Hawk. He also read about the earlier submarine
designs in America during the Revolutionary and Civil Wars, and

(05:31):
Holland was interested in these in large part because Ireland
was under British control and conditions in Ireland were pretty
harsh and a lot of blame was being thrown towards
the British. Not only was there famine and disease in Ireland,
but also some ruthless business practices were turning Irish families
out on the streets. There was even a practice called

(05:51):
leveling in which a landlord would evict a family, then
strip the thatched roof off of that family's house in
an effort to prevent them from moving back into their
former homes. Holland was therefore interested in technologies that might
help turn the scales against a force that otherwise could
seem insurmountable. England's navy was the envy of the world,

(06:15):
so how could Ireland ever stand up to them? Holland
would immigrate to the United States in eighteen seventy three,
and not long after he arrived, he fell and broke
his leg, and he was laid up for a few months.
So to occupy his mind, he began to seriously consider
how one might overcome the challenges of building a practical submarine.
He continued working on his ideas for a new submarine,

(06:37):
and then he presented those ideas to the United States
Navy in eighteen seventy five. The Navy initially dismissed the
designs as quote a fantastic scheme of a civilian landsman
end quote. The Navy was famously skeptical of submarines. Holland, undeterred,

(06:58):
made a model nearly three ftlaw It's about thirty three
or four cimeters in length, and demonstrated it at Coney
Island in New York. The Fenian Brotherhood, which was an
organization made up of Irish and Irish American people who
believed Ireland had a natural right to independence from Britain,
would end up funding his efforts to build a larger

(07:19):
working model. This one, about twice the size of the original,
was called the Fenian Ram in an article in The
New York Sun. It was not named that by Holland himself.
The Fenian Ram would reduce its buoyancy by taking on water,
you know, otherwise known as ballast, but overall it would
maintain positive bulliancy, so it wouldn't just sink to the bottom.

(07:41):
It would actually bob up to the surface. But to
maintain its position under water, the Fenian Ram depended upon
a set of horizontal planes. They actually called them horizontal
rudders back then. They're kind of like airplane wings, but
you could angle them so that when there was forward
motion from the submarine in the water, the water itself

(08:01):
would push the submarine downward as it flowed over these
horizontal planes, so kind of like how an airplane's wings
create the lift in order to lift an airplane off
the ground. These were sort of doing lift but in reverse.
So if the sub we're moving, it could remain under water.
But if it stopped moving, let's say the engine failed,

(08:24):
then it would at least in theory, bob up to
the surface and then whoever was in the submarine could
get the heck out of it. The Fenian Ram also
had a pneumatic gun that it could fire steel projectiles from,
and those steel projectiles would be filled with dynamite, which
sounds super safe. So this was kind of like a

(08:46):
very primitive torpedo. And when not in use, then the
guns who would be sealed with a cap, so you
would have the cap in place until you're ready to fire,
and then you would have to move the cap out
of the way, fire the gun, and then hope for
the best. I guess some shenanigans among the members of

(09:07):
the Fenian Society would sour Holland on the whole experience.
In fact, one faction of this group it sort of
broke apart, and one faction ended up stealing the Fenian
Ram and almost immediately sunk it. Holland refused to work
with them. They ended up storing it in a shed,

(09:28):
and he famously said something along the lines of I
hope it rots on their hands. He did continue to
work on innovations with submarines, and in his mind the
goal would be not to escalate tensions between Ireland and Britain,
but rather to pave the way for world peace. He
was thinking, well, if you know your enemy has a

(09:49):
weapon that you cannot detect, you cannot see it, and
that weapon could sneak up on you and destroy your
most powerful ships, then you're not going to be aggressive
towards that country, right. You already know if you're aggressive
toward them, they can attack you without you seeing them,
and they can lay waste to your forces and your shipping,

(10:10):
and so it makes sense you'll back off. And then
if everybody has these, no one would dare attack anybody else. So,
in other words, it would be a weapon of deterrence.
And it's sort of the same concept that would underlay
the whole mutual destruction philosophy during the Cold War. And
as we know, due to hindsight, this idea rarely works out.

(10:32):
I mean, you could argue that the conditions in Europe
leading up to World War One were kind of similar
If everyone built up these big armies, no one would
ever be so foolhardy as to use them. But at
some point or another, someone tends to decide that it's
worth the risk. We were lucky than no one thought
that during the Cold War with nuclear proliferation, and we

(10:55):
can only hope that the same will prove true in
the future. Anyway, Holland would end working as a draftsman
for many years until the early eighteen nineties when the U. S.
Navy called for submissions for the design of a submarine.
So the U. S. Navy was starting to come around
to the idea. At this point, Holland decided to make
an effort to win a contract with the Navy, and

(11:16):
he sank a lot of his own money into this
project and then sought investments from some businessmen to complete
his submission. They formed what would become the Electric Boat Company,
which would own all of Holland's patents. The Navy would
insist on certain elements in the design, and Holland objected

(11:36):
to those elements. Primarily, he objected to the inclusion of
a steam engine because well, it would be really hot,
but it was also what all the Navy's ships were
relying upon for propulsion at the time, that this was
what was generating the the power needed to propel ships,
so they wanted their submarines to be working on the

(11:57):
same principle. Holland pointed out that a boiler set a
submarine would cause the interior of the submarine to heat
up to intolerable levels. Even argued that maybe if you
want to have a steamer, if you want to have
a boiler on the ship, at least let me use
some insulation to help shield the operator from the heat.
But the Navy said, no, we don't do that for

(12:18):
any of our ships. And the Electric Boat Company would
comply with the Navy's orders and began to build a
ship called the Plunger. But Holland's concerns proved to be
on point. It was and you just couldn't stand to
be inside this thing with the boiler going. It was
just way too hot. The Navy would decide not to

(12:38):
commission the Plunger, so the Plunger was never officially a
Navy ship. Holland convinced his business partners to let him
design an alternative to the Plunger. It was a submarine
that he would call the Holland six. He had built
five previous submarines. The Plunger was technically the Holland five.
He was able to launch a new prototype submarine on

(13:02):
May seventeen. This submarine was innovative for a couple of reasons.
One is that it used a gasoline powered engine to
operate when the submarine was surfaced. When it would go
below the waves, then it could switch to a system
of batteries and electric motors. The advances and electricity meant

(13:23):
that Holland could build a system that didn't require combustion.
Combustion works great when you have a way to vent
fumes and you also have access to oxygen, because it
needs oxygen in order for it to work, but if
you're in an underwater tube, the combustion is not the
most ideal method to power your propulsion system. The electric

(13:43):
motors made it possible to build a submarine that could
operate without the limitations of manpower or compressed air, though
you would have to surface and run the submarine on
its gasoline powered engine in order to recharge the batteries.
Holland changed the center of buoyancy for this ship, as
well earlier ships that he had built had put the

(14:05):
center of buoyancy very very close to the center of
the ship itself, so right smack dab along the middle
of the length of the ship. Holland decided to change
his design so that the center of buoyancy was moved
further forward in the submarines frame. This would become a
common feature in submarines after Holland's design. His ship had

(14:26):
compressed air tanks as well. These were there to supply
fresh air to the operator while the ship was going underwater.
Had a telescoping air vent that could access air above
water when the ship was not far from the surface,
and of course the operator could open up the hatch
of the submarine itself to access air once the submarine

(14:47):
had surfaced. It's highly recommended you do not open the
hatch when you're underwater. One other innovation that Holland made
was in the ballast tanks. Earlier submarines had problems with
stability when water in the ballast tanks would slash around.
I talked about that with l Planeur, the French submarine
from the last episode. So Holland's solution was to make

(15:10):
certain the ballast tanks would be completely full with no
free air space inside of them. That way, the water
couldn't slash at all. It was completely occupying the space
inside the ballast tanks. That allowed for controlled diving and
ascending using just those horizontal rudders, those horizontal planes I
mentioned earlier, and using the forward motion of the ship

(15:32):
to guide the submarine. He also moved the horizontal rudders
to the end of the ship towards the propellers, and
that meant that a small change in the orientation of
the rudder would result in a much greater change for
the rest of the ship. It's kind of like the
lever effect. Holland demonstrated the Holland six to the Navy,
which put it through numerous paces. The Navy was staffed

(15:55):
with admirals who were still incredibly skeptical about the capabilities
of an underwater ship. I mean, there was no deck
for you to strut upon and to be all grand
and stuff while you commanded your men too, you know,
needlessly sacrifice themselves over and over again. So how could
this be a proper use of a sailor's time? But

(16:17):
the Holland six completed all the tests very well, and
ultimately the Navy commissioned the ship as the USS Holland,
and The Holland would become the first real practical submarine
in the U. S. Navy's fleet, and it established the U. S.
Navy's submarine force. The Holland was armed as well. Originally
it had three armaments. One was a torpedo tube from

(16:39):
which the Holland could fire whitehead torpedoes like the ones
I mentioned earlier. A secondary port above that one would
allow for a pneumatic gun to fire what they called
air torpedoes, pretty much what the Fenian Ram could do.
There was a third gun, which was another pneumatic dynamite
gun that would face backward. It's on the stern of

(17:01):
the submarine and would face behind it. The stern gun
would end up being scrapped in favor of an improved
exhaust system, since the gasoline engine would generate some pretty
nasty fumes in operation and needed to have a clear
way to exhaust those fumes and get fresh oxygen into
the combustion chamber. The Holland served as a Navy ship,
largely being used in experimental missions to help refine the

(17:23):
design and construction of future submarines, but by the nineteen thirties,
the Navy had decommissioned the Holland and she was scrapped
in Boston, and only a plate bearing her name remains,
a metal plate that is not a dinner plate. As
for the Electric Boat Company, they would sell submarines to
the U. S. Navy, to Japan, to Russia, and even

(17:47):
to the Royal Navy of the United Kingdom, the dreaded
force that Holland had plotted against many years earlier. As
for Holland, he would work for the Electric Boat Company,
but over time he began to dis agree with the
board of directors, primarily over submarine designs that he considered
to be unsafe. After several accidents on submarines, many named

(18:09):
after Holland himself, he decided to resign from the company.
He retired by seven and he died about seven years later,
just before World War One, when the submarine would be
put to great use in war. I'll explain more in
just a moment, but first let's take a quick break.

(18:34):
One thing I want to talk about before I get
right back into the history of submarines is the use
of periscopes, and a periscope is a device mint to
conduct light from one area to another for the purposes
of seeing what the heck is going on in some
area that would otherwise be inaccessible. So it's done with
mirrors and prisms, and it captures the light from one

(18:55):
spot and then conducts that light to another spot. It's
kind of like looking through the viewfinder of a camera,
except that the lens is positioned somewhere, you know, maybe
several feet away from you, like above you, and uh.
It's an ingenious invention. And there are not a lot
of details about when periscopes were first added to submarines.

(19:17):
They had been known for a long time before submarines
started to use them, but it was fairly early on
with submarines to to have periscopes. Collapsible periscopes would have
to wait for a little bit longer, but even they
would become pretty common for submarines by the nineteen tens.
With a periscope, a submariner could get a look at

(19:39):
what was around a submarine without the sub having to
fully surface and you know, someone would have to open
up a hatch and stick their head out and go,
what's going on this side. With Holland's innovations, more companies
began building submarines, and because of the clear military applications,
the world powers all got into the game. Over in Germany,

(20:00):
shipbuilders were making onto our sea boats or U boats,
while Holland was demonstrating his gasoline electric hybrid. Germans were
working with steam powered subs, but engineers soon graduated to
other types of engines, and by the early nineteen tens,
Germany had successfully launched submarines using diesel engines when they

(20:23):
were on the surface and electric systems when they were underwater.
One class of these submarines, the Unite teen class, would
end up playing a pivotal role during World War One.
Submarines were still a new concept in naval warfare, and
they proved to be devastatingly effective in disrupting shipping lines.

(20:45):
A submarine could approach a target ship with almost no
warning before firing upon it, and it didn't take long
for the British to look into ways to counteract the
threat of submarines, leading to the development of explosives that
could be set off under water. These became known as
depth charges. They weren't effective as weapons unless they happened

(21:06):
to explode really close to a submarine, but they were
effective deterrence, probably because being aboard a submarine that's just
in decent working order is already pretty darn risky. If
you start hearing explosions going off, even if they're not
right next to you, you're probably having a lot of
second thoughts. In nineteen fifteen, a U nineteen class submarine

(21:28):
called s m U twenty and yes, I know it's confusing,
but that's because there were four submarines that were in
the U nineteen class, the first of which was U
nineteen and then the other's U twenty twenty one and
you twenty two. Anyway, it fired on a cruise liner
called the Lusitania. The ship was struck by a torpedo

(21:48):
and it sank in less than twenty minutes, with the
loss of nearly twelve hundred people. The Germans maintained that
the Lusitania was being used to move munitions in addition
to acting as a cruise liner, which the UK government
denied for decades until more recent years when they owned
up to it because salvage operations would have encountered potentially

(22:12):
dangerous conditions due to the explosives that were in fact
on board the Lusitania. The sinking of The Lusitania, which
had nearly a hundred thirty American citizens on board, would
also end up setting the stage for America to get
directly involved in the conflict a couple of years later. Now,
this involves having to talk about some political concepts that

(22:35):
are not directly related to submarines. Germany's use of submarines
prompted the UK to outfit some merchant ships with heavy
guns that could easily be concealed and then brought to
bear on a submarine once it's surfaced. These ships were bait. Essentially,
they were bait meant to lure German U boat commanders
to maneuver into a position where the U boats could

(22:57):
be attacked and you could are you that it was
this practice that set the conditions necessary for a tragedy
like the sinking of the Lusitania to happen. So let
me explain. For more than a century, the practice was
for all military ships to follow what we're called cruiser

(23:19):
rules or prize rules. These rules stated that a government's
ships would not fire upon civilian or merchant vessels without warning.
So you could stop a vessel, You could sail up
to a merchant ship or a civilian ship, and you
could demand that they do whatever. They could surrender the

(23:42):
boat or they could leave the area, and then if
they did not do that, then you would have the
authorization to fire upon that ship. But you couldn't just
fire upon them with no warning. And typically the way
this would work is that you would stop a ship.
You would then transport all the crew and passengers off

(24:02):
of the ship to some safe location, and then you
could search the vessel for any sort of contraband like munitions.
The Q fifteen boats those are the heavily armed merchant
vessels that the British were creating. They could fire upon
a submarine that had surfaced before the submarine could fire back.

(24:23):
Because the submarine would surface, the submarines captain would be
following the cruiser rules to demand to search a vessel.
In the meantime, the crew aboard one of these Q
fifteen boats could bring the guns to bear and fire
upon the submarine. This was considered unfair by the submarine operators,

(24:43):
after all, they were following the rules. They were saying, hey,
we're not just opening up fire on these ships. We're
you know, following the protocol. So then Germany decided to
adopt a different set of philosophies unrestricted marine warfare, which
means that if a ship is in an area that

(25:04):
was considered a war zone, it was fair game. Didn't
matter if it was a merchant ship, a civilian ship,
a military ship. It would mean that a submarine or
any ship captain could fire upon it because it was
in a war zone. And that gets us to the
sinking of the Lusitania. Because the Lusitania was in such
a zone and the Unit twenty submarine fired upon it,

(25:29):
the United States government demanded that Germany stop all kinds
of unrestricted submarine warfare operations, and Germany initially agreed. You know,
in the United States was not in World War One yet,
so Germany didn't want to to get the US involved
because that would turn the tide and make things much

(25:49):
more difficult, so they agreed, But then eventually they returned
to an unrestricted approach in nineteen seventeen, uh for lots
of reasons that I won't get into because it goes
beyond this podcast. But that meant that the United States
entered World War One, and I realized all of this
has more to do with the use of submarines rather
than in how they work. But I figure it was

(26:10):
also an important point to touch upon and it shows
how the response to the submarine threat really made Holland's
dream of ending warfare a naive wish, right. It didn't
turn out that the submarine was so terrifying that it
made war have to stop. It just made war different.
The U nineteen class submarine was much larger than the

(26:33):
Holland class subs that were being used by the Royal Navy.
These were also slightly different from the US version of
the Holland submarines were based on the same design, so
let's do some comparison. The Holland class sub measured sixty
three ft ten inches long that's about nineteen and a
half meters, and it was eleven ft nine inches across

(26:55):
or three point six meters, and it carried a crew
of eight sailors. It had a single torpedo tube. The
U nineteen was two hundred ten and a half feet
long or nearly sixty four point two meters, It was
twenty feet or six point one meters wide, and it
carried a complement of thirty five sailors. The U nineteen

(27:17):
had dual eight cylinder diesel engines, and two motors for propulsion.
She could reach a speed of fifteen and a half
knots that's about eighteen miles per hour on the surface,
or nine and a half knots or eleven miles per
hour when submerged. She could also travel eleven thousand, two
hundred miles or around eighteen thousand kilometers if she was

(27:38):
traveling when surfaced, she could dive to a depth of
a hundred sixty four feet. She couldn't travel underwater for
very long, however, because like the Holland, she would switch
to electrical power and that would quickly drain the batteries.
Battery technology in nineteen seventeen was not that great. The
diesel engines could power dynamos to recharge the battery is

(28:00):
once the ship's surfaced, so most of the time it
traveled above the water, and typically would only go under
the water when preparing to attack a target. The U
nineteen class had four five hundred millimeter torpedo tubes, two
in the bow and two in the stern, and it
would also carry six torpedo reloads. After nineteen sixteen, the

(28:21):
submarines would also have a deck gun, and there were
four submarines in that class. Like I said U nineteen
to U twenty two. Germany would go on to develop
other classes of submarines, like the UB class, which were
meant for coastal operations. They would not venture that far
from Germany, so they were more limited in their capabilities,

(28:41):
but that just meant that they were also faster and
more nimble than their bigger cousins. Then you had the
long range submarine cruiser that was the U A class.
These subs were real beasts. They were longer than the
U nineteen, They were able to travel further and faster,
and carried a complement of fifty six sailors with room
for twenty more people aboard the ship. Germany planned to

(29:05):
make forty seven of the U A submarines, but only
nine had been completed before the war ended. During the
course of World War One, the German submarines would be
responsible for sinking around four thousand ships, and Germany would
lose around one hundred seventy three submarines in the process.
By the time the United States entered World War One,

(29:26):
it was clear that the country was way behind when
it came to submarines. The country that had served as
the home for the first practical submarine was now left
in the wake, so to speak. An engineer named Simon
Lake had designed submarines for the U. S. Navy, but
these were mostly used for experimental purposes. One of them

(29:47):
set a depth record in nine of two hundred sixty
five feet or seventy eight meters. For example, the U. S.
Navy had classified their submarines by letter, so by the
time you get to the L class submarine, which launched
in nineteen fourteen, that one took nearly two and a
half minutes to dive beneath the surface of the ocean.

(30:08):
Compare that to the UB class submarine, the coastal submarine
in Germany, that could do the same thing in less
than thirty seconds. Meanwhile, scientists and engineers began developing a
technology that could detect submarines underwater, and it would ultimately
get called sonar, which would retroactively become an acronym for
sound navigation and ranging. The concept is pretty simple. In fact,

(30:32):
for passive sonar it's dead simple, because really it just
means listening for sounds made by vehicles like submarines. So
it involved developing hydrophones, essentially microphones that can work underwater.
But even if we go with active sonar, it's pretty
easy to understand. It's all based off echolocation. Basically, the

(30:54):
ideas that you send out a sound like a low
pitched ping noise. Low frequency sounds can travel pretty far.
The sound travels through the water until it hits the
surface and then it bounces back. And by measuring the
amount of time it took for a sound to leave
and then to return to you, and presuming you know
what the speed of sound is through the water you

(31:15):
are in, you can get an idea of how far
away an object is. And by doing it a lot
of times, you can also figure out if whatever the
thing is is traveling toward you or away from you,
what the size of it is. Lots of information like that. Now,
while this was initially developed as a means of just
detecting and thus targeting submarines in warfare, engineers would adapt

(31:35):
sonar so it could be used as a navigation system
aboard submarines. In general, sub mariners have to rely upon
a collection of gauges and meters when they are underwater.
Military submarines don't have windows, and besides, once you dive
down a bit, it's just it's so dark that you
can't navigate by sight anyway. So you need to know

(31:56):
where you are. You need to know how fast you
are traveling, how far you are going, which might not
be intuitive depending upon whether you're traveling with or against
the current, how deep you are, how deep the water
is so, how much more space do you have below
you before you hit ground, and whether or not there's

(32:18):
anything you need to worry about around you, like any
types of of wreckage or sandbars or things like that.
Sonar we become a huge help, as it would let
the navigation crew know if there were something they needed
to maneuver around, and over time submarine crews were creating
incredibly detailed maps of various areas of the ocean, which

(32:40):
was necessary if you wanted to pilot your submarine without
having to scrape up against something or get embedded in
mud or sand. When we come back, i'll talk about
the advancements in submarine technology during the Second World War
and beyond, But first let's take another quick break. After

(33:02):
World War One, many countries signed treaties that placed limits
on stuff like how big a navy a country would
be allowed to have. You know, we were starting to
figure out, hey, maybe if we don't constrain ourselves to
the size of our militaries, that just leads to these
massive conflicts. This would in turn have an effect on shipbuilders,

(33:23):
really anyone who was in the military industrial complex, people
who found themselves on uh shaky ground because they couldn't
land those sweet military contracts anymore because those limitations. One
thing that did happen in nineteen nineteen, after World War
One had already ended, was that a German U boat

(33:44):
was sunk in American waters. This was actually a matter
of propaganda. The U SEE ninety seven was turned over
to the U. S. Navy, which studied it, and then
it was sent to go on sort of a victory
tour or on the Great Lakes. People American citizens could
get a look at one of the dreaded U boats,

(34:07):
and an event was planned on Lake Michigan, during which
the submarine was purposefully sunk, presumably too great applause. The U. S.
Navy had been using an alpha numeric classification system for
its submarines, working up the alphabet with each new class
of sub Like I mentioned the L class earlier, which

(34:27):
was a pre World War One class of submarine, Once
the US hit the S class of submarines, things changed.
They changed the naming convention and the name of a
submarine would begin with the letters S S and then
a number, and the names for the classes would be

(34:47):
given names, often of of c creatures, and they were
typically named after the first submarine of that class. So
the very first of these was the Barracuda class submarines
designated S S one sixty three through S S one
sixty five, so there are three of them. Uh, the
individual submarines each had named, So you had Barracuda, after

(35:09):
which the class was named, and you also had the
Bonita and the Bass. Meanwhile, in Japan, the Japanese took
possession of seven German U boats and then invited nearly
one thousand German experts in the design, construction, and operation
of submarines to jump start Japan's efforts to have its
own submarine fleet, which would become very important for Japan

(35:31):
during World War Two. By treaty, Germany was technically forbidden
to have a submarine fleet, but the country secretly began
developing the next generation of submarine technology and even purchased
a Dutch ship building company that had been designing submarines
for the international market. In the United States, in nineteen five,

(35:51):
some accidents involving submarines and surface ships had resulted in
the death of many submariners, and that prompted new efforts
to create mean of escaping a sinking submarine. A submariner
named Charles Swede Momson came up with an idea a
special rescue chamber kind of a modified diving bell thing

(36:12):
that could be lowered from a surface ship to dock
with the submarines escape hatch and provide a safe way
for submariners to abandon ship. His basic design was later
refined by Alan Rockwell McCann, after whom the device would
get its name, the McCann Submarine Rescue Chamber. The chamber
would prove its worth in nineteen thirty nine when the
Navy used it to rescue thirty three surviving crew members

(36:35):
from a submarine called the Squalis. It had sunk after
an accident. There was an explosion, part of the submarine flooded.
All of the crew in that part of the submarine
were lost, and the other thirty three we were able
to be rescued using this particular rescue chamber. In the
mid nineteen thirties, Germany renounced the Treaty of Versailles and

(36:56):
the U one series of submarines went into action. Germany
again a new strategy called wolf pack, in which groups
of seven to eight submarines would form night attacks on targets.
Then they would submerge to escape, and once the submarines
reached a sufficient distance from their targets and presumably detection,

(37:17):
they would resurface, and then they would sail to the
next attack zone to prepare for the following night. The
submarines fell into categories like coastal submarines, long range boats,
and then Germany also had a Type seven submarine. This
was meant to fill in depending on what was needed
at the time, so kind of a jack of all

(37:39):
trades submarine. Germany would build more than seven hundred submarines
across these different classifications throughout the course of World War Two.
One German innovation in World War two got around a
huge problem that submariners had been having since the invention
of the submarine. It couldn't stay submerged indefinitely because of

(37:59):
a couple of big problems. One was that the electrical
systems would drain the batteries and then they'd be without power.
Plus they'd have to get access to atmospheric air occasionally
because they could only carry so much air aboard the ship.
A German scientist named Hellmuth Vaulter figured out that by
using a high concentration of hydrogen peroxide, he could solve

(38:22):
both of those issues at once. The H two O
two would release an enormous amount of heat as it
broke down, which could then be used to generate steam
to turn a turbine and power and electrical generator, and
a convenient byproduct of this process would be oxygen. The design,
while capable of generating enough energy to move a sub

(38:45):
at a very zippy speed compared to its diesel engine variants,
would also require a lot of hydrogen peroxide. It was
determined to be about twenty five times more fuel hungry
than a d Old powered submarine, so it was thought
to be expensive and not terribly practical. Plus at the time,

(39:07):
Hitler was pretty sure he had this whole war thing
sewn up. At that point, this would be around nineteen
forty and so Germany never pursued the concept any further.
While the US wasn't yet involved in World War two.
At that point, the country did escalate its submarine manufacturing efforts.
The Navy settled on two designs for submarines to serve

(39:29):
as the template sports World War two subs. The first,
established in nineteen forty, was the Gotto class, and the
second class, called Balao, was essentially the same as the Gotto,
but with some improvements added to the design. Now I'm
going to skip to the end of World War Two
here because otherwise this would become a very long laundry

(39:51):
list of battles and encounters, and that's not really this
show's focus. There also be some crossover to other topics
I've covered in the past, such as code breaking, because
that would become an important part of the various war efforts,
both on the Axis and the Allied sides, and it
very much was centered around submarine operations. But I've covered

(40:14):
that in other shows. And by the end of the war,
Germany had lost more than eight hundred submarines, so not
just the seven hundred had produced, but some that it
had still had on its own. The United States lost
fifty two submarines, Russia lost a hundred nine submarines. Russia
had also begun the war with the largest submarine fleet,

(40:35):
but during the course of the war, their manufacturing was
far outpaced by other countries. By ninety eight, the United
States began to experiment with sub launched missile systems, so
you could launch missiles from submarines. By nineteen fifty three,
United States submarines could carry nuclear missiles, which made them

(40:57):
particularly dangerous useful in the Cold War. If you can
create a nuclear missile launch facility, then you can park
it off the coast of whatever country you're looking at.
You didn't have to worry if the missile itself couldn't
travel the entire length of the globe. In nineteen fifty four,

(41:19):
the United States launched the Nautilus, a very popular name
for submarines. This version of the Nautilus would have a
nuclear powered engine in it, So this was the first
nuclear powered submarine. And I've talked a little bit in
other episodes about how nuclear power works. Essentially, you have
a controlled nuclear decay process and that generates a lot

(41:42):
of heat, use that heat to boil water into steam,
and you use the steam to turn turbines which are
part of an electrical generator system. The United States has
lost two such nuclear submarines, both in accidents. One happened
in nineteen sixty three. That submarine was called the thresh Sure,
and no one knows for sure what exactly happened leading

(42:04):
up to the accident. The submarine sank in water that
was about seven thousand feet deeper than what the submarines
whole could withstand, so there was very likely total whole
collapse before the submarine settled to the bottom, and it
demonstrated that there was a need to develop a rescue
system that could work at much greater depths than the

(42:27):
mccan rescue chamber, and that led to the development of
the Deep Submergence Rescue Vehicle or d s r V.
These are like submarine lifeboats. They can navigate down to
a maximum depth of five thousand feet and they are
designed to dock with the escape hatch of a submarine,
so you would transfer submariners over to this smaller submersible

(42:51):
vehicle and then navigate away from the sunken sub The
second accident happened in nineteen sixty eight with the USS Scorpion,
which may have sunk due to an accident with one
of the submarine's own torpedoes. There's other stuff that I
could also cover in this episode. I haven't really touched

(43:13):
on a lot of the life support system improvements over
the years, so let's talk about that for a second,
because obviously these are really important. All the older subs,
you know, they had things like snorkels, and they would
get up enough, you know, close enough to the surface
where the snorkels could open up and get a little
bit of fresh air into the submarine. Otherwise you had
to open up the hatch to air it out, but

(43:35):
that doesn't really work if you're doing prolonged operations under
the water. You have other issues you have to worry about.
For example, you've got to figure out how to get
all that carbon dioxide out of the ship, because at
higher concentrations of c O two you get to toxic
levels and people will die. So to take care of that, submarines,

(43:57):
particularly in the nuclear era where US some ring could
at least in theory, operate for weeks without surfacing, you
have to carry what are called scrubbers, and these rely
on chemical compounds that essentially absorb carbon dioxide. So the
carbon doxide gets absorbed by these chemicals and then you

(44:18):
can treat those scrubbers to remove the CEO two, typically
by heating it up, and then the CEO two gets released.
You can capture the released CEO two and a UH
in a pressurized tank and then you can essentially jettison
the CEO two into the ocean. So that's how we
make sure that CEO two levels don't build up. On

(44:39):
top of that, you also need things like D humidifiers
because as we you know, as we exhale, we're not
just excelling carbon dioxide, we're also excelling water vapor, and
so without D humidifiers to capture some of that water vapor,
you have a lot of condensation building up all over
a shop. Pretty soon everything would be moist. What a

(45:03):
great word, huh. To produce oxygen, the submarine can typically
take on sea water and run it through a desalination
process to create fresh water, so you're removing the salt
from the ocean water. Then with the freshwater, you apply
an electric current to that water. The electric current breaks
down the molecular bond between hydrogen and oxygen, so as

(45:26):
a result, it starts to bubble and you get oxygen
and hydrogen gas. This process is called electrolysis. And it's
how modern submarines replenish the supply of oxygen within a
sub even if it operates underwater for weeks at a time.
I also didn't go into detail over the various meters
and gauges that you'd find aboard a submarine to monitor

(45:46):
the sub's heading, its position, the amount of pressure on
the whole, and other factors. But then to do so
would require two or three more episodes. And I'm sure
I'll get around to it in the future and I'll
over how those different pieces of submarines work. I think
that this topic is fascinating. I personally have toured a

(46:08):
few submarines, including a World War Two era submarine. In fact,
I remember my wife and I toured the submarine and
we were part of a tour group that was just
four people. In fact, we thought it was just gonna
be my wife and I at first, but then these
two tourists joined us and a submarner took us on
a tour of a World War two era submarine. We

(46:29):
were amazed at how small everything was. The average submariner
was of a slightly uh shorter than average height you
had to be. The facilities were very small, the quarters.
The bunks and stuff were quite small, and uh, we
were taken through and we realized that the other two

(46:50):
people in our group, um we're German, probably still are
and that made things interesting because we were talking about
a World War two era submarine. But then the sub
mariner aboard cheerfully pointed out that that particular submarine had
been used in the Pacific theater so far away from
German ships, which seemed to make everything go much more

(47:13):
smoothly for the rest of the tour. It was really
neat to get a firsthand look at a submarine, and
I recommend that if you get a chance to tour
a military submarine to check it out because it will
give you a real appreciation for what sub mariners go through.
They typically get additional hazard pay and it's completely understandable.

(47:35):
The quarters are tight. You have no view of the
outside world, and chances are that if you're on a
nuclear powered submarine, you may not see the outside world
for weeks at a time. You're you know, breathing in
this air that's been processed through electrolysis. It's it's a
different kind of experience and um, yeah, it definitely opens

(47:58):
up your eyes to how strange that world must be.
And that wraps up this episode and the two episode
overview of how submarines work. Like I said, there's a
lot more that we could go into, and in the future,
I probably will revisit this topic and give more details.
But I hope that this gives you an appreciation for
the development and evolution of the submarine and uh, if

(48:21):
you guys have suggestions for future episodes, you can reach
out to me the email addresses tech stuff at how
stuff works dot com, or you can pop on over
to our website that's text stuff podcast dot com. You'll
find links to where we are on social media. You'll
find an archive of all of our past episodes there,
and it's completely searchable so you can check and see
if I've already covered a topic. And you'll also find

(48:44):
a link to our online store where every purchase you
make ghost help the show and greatly appreciate it, and
I'll talk to you again really soon. Text Stuff is
a production of I Heart Radio's How Stuff Works. For
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(49:05):
your favorite shows. H