Table of Contents

Introduction..1 Basics....2 Propulsion..3 Early Submarines4 The Turtle5 Civil War ....6 Mechanical Power.7 Diesel Electric8 Armament.....9 World at War.10 World War II: Atlantic..11 World War II: Pacific.12 Nuclear Power13 Nuclear Submarines..14 Life on a Submarine15 Polar Ice Expeditions.16 Civil Use....17 Dangers and Accident Prevention..18 Future.20 Glossary.21 Picture Sources....22 About the Authors..23

Introduction

Meaning the under the sea, the word submarine is the combination of

sub and marine. Submarines are vessels specifically design to dive and

operate freely under water. They should not be confused with

submersibles, which are unable to operate independent of a mother ship.

The earliest submarines were little more than small wooden vessels that

could accommodate only a few sailors and could operate over a very

limited range. Modern submarines, however, are massive ships which are

capable of remaining submerged for months at a time and are able to

cover thousands of miles. Submarines are incredibly useful as well; they

are valuable both commercially and militarily.

The picture above is a cross sectional view of a modern submarine.

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Basics

Ships float on water because of buoyancy. All fluids exert pressure,

water included. It is this pressure that assist in keeping objects afloat.

While buoyancy helps ships stay above the surface of the water, it also

makes it difficult to submerge a submarine. In order to dive, the

submarine must overcome buoyancy. This is done by filling the ballast

tanks with water, weighing down the vessel, and sinking it.

Submarines must also protect the crew serving on the vessel from the

harsh underwater environment. Not only must the crew be supplied

with oxygen, but they must be protected from the immense pressure

water exerts. As a result, submarines are built with a pressurized

interior cabin where the crew can work safely. Shown in the diagram

above, are both the ballast tanks, as well as the pressurized interior of

the submarine.

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Propulsion

The earliest submarines used either oars or a corkscrew to provide

propulsion. While they did work, these two propulsion devices were

inefficient; therefore, the propeller was adopted. A propeller works by

pushing water much like a fan blows air. Using angled blades, the

propeller moves the fluid backwards, which in turn propels the ship

forwards.

While the propeller is still standard, some ships deploy pump jets to

provide propulsion. A pump jet is an enclosed propeller system that

produces less noise than a conventional propeller, making any ship using

one stealthier. In addition, pump jets add maneuverability because the

direction of the resulting current of water can be changed. Pump jets are

more expensive, and they do negatively affect performance, such as the

case with fuel economy.

A pump jet.

A diagram of a pump jet

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Early Submarines

There is evidence that the ancient Greeks used a precursor to the

submarine, the diving bell. This was a vessel that could be lowered

underwater and held a small volume of air. It allowed the operator to

stay under the surface for a longer period of time. Diving bells are not

true submarines, which first appeared hundreds of years later.

Two early submarine designs, the design on the left dates from the fourteenth

century and the design on the right dates from the fifteenth century.

The first submarine to be built and successfully operated was

designed by a British Mathematician named William Bourne and

constructed by Cornelius Drebble. In the seventeen century, Drebble

tested the submarine in the Thames. It was received with much praise

and at one point King James I was a passenger on the vessels.

A painting of Drebbles submarine in action

Aajad

Designed by David Bushnell in 1776, the Turtle was to be used against

the British in the American War of Independence. The Turtle was an egg

shaped vessel equipped with a mine, specially designed to detonate in

water. Unfortunately for the Americans, the Turtles top speed was 3 mile

per hour in calm waters; this was largely due to the non-hydrodynamic

shape and insufficient propulsion system.

A sketch of Bushnells Turtle

According to an American account the Turtle was once used in

combat. On September 7, 1776, a volunteer attempted to sink the HMS

Eagle using the submarine. The attack ultimately failed when the Turtle

was unable to plant its charge on the ship and had to abandon the mission.

The mine was detached from the submarine and later detonated harmlessly

in New York harbor. The Royal Navy had no records of such an attack, and it

may be very likely that the attack never occurred. If the story is true

however, the Turtle would be the first submarine ever to be used in a

military action.

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The Turtle

The American Civil War is considered the first modern war and the

submarine was first effectively used in it. Both the Union and the

Confederacy built various types of submarines. Their philosophies differed

greatly; while the Union believed submarines could be used in a support

role, clearing underwater obstacle and mines, the Confederacy used them

in an attack role. Throughout the Civil War several advances to submarines

were made, including designs for steam and electrically powered vessels,

compressed air tanks, airlocks and even carbon dioxide scrubbers. In total,

over twenty submarines were constructed during the war. The most

famous submarines were the Union Alligator, an advanced craft that

influenced the future designs of many submarines, and the Confederate

Hunley, the first submarine to sink a ship.

The Alligator

The Hunley

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Civil War Submarines

The Sinking of the Housatonic By 1864, Charleston Harbor was under a Union blockade. On February 17, the

Hunley was deployed in an attempt to break the blockade; the target was the sloop,

U.S.S Housatonic. That night at 8:45, the Hunley and her crew of eight made their

approach while receiving small arms fire from the Union ship. After affixing an

explosive to Housatonic, the crew quickly retreated. The Housatonic sunk moments

later. The Hunley made the first successful attack in submarine history. Unfortunately

the submarine was lost in the process, going down with all hands.

Although mechanically powered submarines were proposed during

the Civil War, all of the submarines used were still human powered. As far

back as Drebbles ship, submarines have been moved via oars or propellers

driven by men. The first submarine to use an alternative to man power was

the Plongeur, a French ship driven by compressed air.

The Plongeur was constructed in 1863.

Mechanical power marked a revolution in submarine design and

finally made them a practical craft. All submarines prior had huge

limitations due to dependency on human power. These submarines had

incredibly limited range and speed, and could go only as far as the human

operator could row or crank. With the use of mechanical power,

submarines could move further and faster. In addition size was no longer

limited by the propulsion system and larger ships could be constructed.

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Mechanically Powered Submarines

Powering submarines has always been a problem because coal,

gasoline, and diesel engines all require oxygen to function. When

submerged all the oxygen in the ship is used by the crew, and it is not in

free supply. Motors were considered as an alternative because they require

no oxygen to function. Unfortunately, batteries are heavy and a ship

equipped solely with batteries and motor would have an unreasonable

weight.

The solution was to make a hybrid ship, one that would run on diesel

on the surface and use electric when submerged. Diesel offered great fuel

efficiency and the range that a submarine needs, while the electricity

allowed the ship to run underwater. Originally, these crafts had a propeller

attached to both a diesel engine and an electric motor. In 1928 however a

more efficient system was designed. Rather than using the engine to power

the boat, it would be used to recharge the submarines batteries.

The diesel engine turns a generator producing electricity and

submarine is driven by an electric motor.

Diesel Electric

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The earliest submarines had to physically plant explosives on ships;

needless to say this was not an efficient method. As they increased in size,

the submarines needed a better way to engage and sank enemy vessels.

Two solutions were developed: deck cannons, and the torpedo.

The deck gun would be used to attack ships while the

submarine was at the surface.

Torpedoes are self-propelled explosives that can be either fired from

above or below the surface of the water. In addition, torpedoes have

contact fuses, which detonate the explosive when it contacts a ship. The

first self-propelled torpedo was powered by compressed air. After

torpedoes became self-propelled, a method of maintaining depth was

needed. The solution was made in 1868; a special mechanism was added to

control the fins of the torpedo.

The image above is a sketch of an early

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Armament

Submarines first played major role in World War One. The British

Navy was by far the most powerful navy in the world at the time, and the

German fleet could not match it. The Germans adopted a new strategy to

combat the British fleet, submarine warfare. While all sides had

submarines, only the Germans saw their value and their u-boats were by far

the most advanced submarines of the war.

A German u-boat

Initially, the u-boats were used to attack a military vessel, but the

disadvantages of submarines hindered the effectiveness of the attacks.

Despite being capable of sneaking up to a ship, u-boats were slow,

immovable, and almost blind underwater. Ultimately the Germans could

not seriously hinder the British Navy. They changed tactics and began

attacking merchant vessels in an attempt to cut off resources coming into

Britain.

c

World at War

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The RMS Lusitania On May 7, 1915, the RMS Lusitania and 1,195 occupants became victims of the

German submarine campaigns. The sinking of the ship caused both controversy and

outrage. While the Germans claimed the Lusitania, a luxury liner, was carrying weapons

and ammunition, both the British and American government claimed otherwise. It

changed the American opinion of Germany, who began to view the Germans as savages. A

few years later, when Germany began to pursue unrestricted submarine warfare, America

joined the war effort against Germany.

Almost 20 years later, the German u-boat would once again roam the

seas, deadlier than ever. After their defeat in World War One, Germany

rebuilt under the leadership of Adolf Hitler, and once again relied on the u-

boat to cripple its enemies. The u-boats of World War Two were equipped

with more effective torpedoes, including torpedoes with proximity fuses.

The u-boats were largely used to attack transport vessels in attempt

to cut off the island nation of Britain from outside supplies. During the first

years of the war, the Germany had great success sinking commercial

shipping. Germany also developed the wolfpack, a large formation of

submarines that was very capable of sinking ships. Their success would not

last long however, as the war went on the Allies developed superior anti-

submarine techniques.

Advances to depth charges, the most common anti-submarine weapon, decreased the

amount of ships sunk by U-boats.

Sonar and radar allowed the Allied Navy to detect U-boats on the

surface as well as when submerged. Along with better detection methods,

the Allies developed anti-submarine weapons. In addition aircraft were

equipped with technologies to combat the u-boat threat.

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World War II: Atlantic

Submarines also played a major role in the Pacific theater. The

Japanese had a sizable submarine fleet, and even used midget submarines

to attack ships at Pearl Harbor. In addition, they developed some unique

submarines such as the aircraft carrier submarine.

The I-1400, a Japanese submarine that was capable of launching three aircraft.

After Pearl Harbor, the American surface fleet was decimated, but the

American submarines were untouched. The United States proceeded to

carry out its own unrestricted submarine warfare policy, attacking the

shipping that was vital to the Japanese war effort. Submarines destroyed

over half of the Japanese merchant fleet, crippling the economy of the

island nation. By the end of the war, Japan did not even have enough fuel

to power their naval vessels. Along with offensive roles, the American

submarines were used in support roles such as reconnaissance, and search

and rescue.

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World War II: Pacific

Throughout both World Wars, all submarines were diesel electric.

While these submarines could submerge longer than their predecessors,

they still had to surface to recharge their batteries. After the Second World

War a new power source was available: nuclear power. Unlike diesel

generators, nuclear generators not require oxygen, instead they relied on

uranium.

All matter can be converted into energy, and in fission most of the

matter is converted into usable energy. In nuclear bombs all of the stored

energy of the bombs core, usually uranium, is released all at once,

producing an explosion that can level cities. In nuclear generators the same

amount of energy is released, but over long periods of time. In nuclear

fission the energy stored in matter is released efficiently. A baseball sized

piece of uranium can produce as much power as one million gallons of

gasoline.

In nuclear generators the energy stored in the uranium is released through heat

energy. This heat converts the water, which is pumped in to cool the reactor, into

steam. This steam turns a turbine, which is connected to an electric generator. The

steam cools down, converting back into water, and is pumped through the reactor.

Nuclear Power

Reactor

Turbine

Throttle Valve

Electric Generator

Water Pump Generator

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Many modern submarines utilize nuclear energy to provide power.

Because they do not need to surface to recharge their batteries, submarines

are able to spend much of their time underwater. The only limitation of

how long a submarine can stay underwater is its food supply; the uranium

in the generators can last for 25 years.

The downside of nuclear submarines is a loss of stealth. Nuclear

generators create a great amount of heat. This heat comes directly from the

reactor, and is even produced when the generator is off. In order to keep

the generator from overheating, this heat must be dissipated into the water

surrounding the submarine. This process leaves a thermal scar, an area of

heated water that thermal imaging systems can detect. In addition, the

generator emits a large amount of noise, which comes from the steam and

water running through the reactor. This sound is loud enough to be

detected by other ships.

Nuclear submarines have more tubular shapes then submarines such as the u-boat.

Since nuclear submarines are underwater more often than on the surface, their shape

is designed to be hydrodynamic. This comes at a cost however; the ship is less stable

on the surface.

Nuclear Submarines

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At first, submarines were not suitable for extended habitation. Early

submarines lacked the life support systems that sustain the crews of

modern submarines. However, the invention of diesel-electric engines

allowed larger submarines to be built, which in turn allowed for more

livable ships.

The first aspect of life on a submarine is the tight quarters. Being a

closed metal tube deep underwater, submarines have inevitable space

restraints. In fact, the earliest submarines resembled caskets more than

boats. They were generally built to accommodate only a few occupants,

unlike modern submarines, which can hold upwards of a hundred crew

members. The early submarine had a seat for the pilot and not much else.

They were used more like cars; they were transportation devices used to

move from one place to another. The pilot was not able to leave his seat

except when he was leaving the submarine. The development of newer

submarines brought about the idea of actually living on a submarine.

Shown above is the forward torpedo room of a World War Two era submarine.

Due to the lack of space on the ship, there are actually bunks on top of torpedoes.

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Life on a Submarine

The first attempt to reach the North Pole in a submarine was made by

the US ship Nautilus in 1931, while under the command of Sir Hubert

Wilkins. The expedition was called off after the diving plane was damaged

during travel under the ice. This forced the captain to retreat; however, the

expedition did show that submarines were capable of operation under ice.

However, the ship was seriously damaged in its efforts.

It would take another twenty years for additional attempts to sail

under the North Pole. The honor of being the first ship to reach the North

Pole, and operate under ice for a significant portion of time goes to the USS

Nautilus. This submarine was the successor of the diesel powered Nautilus

of the 1930s, and was the first nuclear submarine. The Nautiluss success

would be followed up by the USS Skate, the first submarine to surface at

the North Pole. It traveled under the ice, and then broke through the

surface at the North Pole on March 19, 1959. Both of these ships conducted

research there for the navy, and proved that submarines could effectively

and safely operate under ice.

.

This picture is of the USS Skate at the North Pole, 1959.

Polar Ice Expedition

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Civil Use

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Although most submarines are used for military purposes, some are used outside the military. Submarines, as well as submersibles, can be used

for tourism, explorations, and investigations of undersea cables and

structures. Tourist submarines first appeared in 1985 and because of

increasing popularity the number these ships today is around forty-five.

The largest passenger submarine is the Atlantis XIV,

which can hold 64 passengers.

Submersibles Submersibles are very useful to scientists who wish to explore underwater.

They are used for oceanography, underwater archeology, ocean exploration, or even

underwater photography or video recording. Being smaller, submersibles are a more

economic choice than submarines. Submersibles can be dropped into deep ocean

trenches. The submersible is tethered to the mother ship, which the submersible is

dependent on for surfacing and refueling. Scientists onboard can control external

robotic appendages to collect samples and conduct experiments. Submersibles excel

in this aspect of underwater research because small size of submersibles makes them

maneuverable in tight areas.

The first submarines were made of wood and were very fragile. A

small hole would be enough to fill the submarine; hitting a large rock, boat,

or even another submarine could be enough to sink the vessel. Newer

submarines are not nearly as weak, but a breach of the hull can still be

disastrous. To prevent the complete filling of the submarine, newer designs

have a hull that is segmented with bulkheads. Each individual section can

be sealed off from the rest should a rupture occur and most of the ship will

remain dry. The submarine will then be able to sail to a port for repairs.

Nuclear submarines have the danger of radiation. If the generator is

not maintained properly, radiation leaks are possible. If one of the pipes

holding steam leaks, the released steam is capable of seriously burning

someone. Submarines contain steam suits, as seen below, to protect the

crew while making repairs. Surprisingly, fire is another danger. In the event

of a fire, the crew cannot just flood the submarine; they would drown if

they did that. Submarines have sprinklers, like those in buildings, to put the

fire out. The sprinklers spray an ultra-fine mist to reduce water usage.

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Dangers and Accident Prevention

Submarines are very complicated machines and reckless actions on

board can have huge consequences. Just one of numerous possible

mistakes can cause the submarine to crash. For example, traveling too deep

or too fast are easy ways to endanger the submarine. If the submarine

sinks while underwater, it is very difficult for crew members to escape.

First, the crew has to deal with the change of water pressure, which can

cause decompression sickness. At deep depths the water pressure is high

enough to kill. If a submarine does sink in deep water, a pressurize rescue

craft is required to evacuate the crew.

The McCann Rescue Chamber is a pressurized vessel that is used to rescue

sailors trapped in a sunken submarine.

The most effective safety precaution is attentiveness. If anything on

the ship seems like it is slightly off, then there is a potential safety hazard.

Standard procedures include checking for any problems, which must be

done thoroughly. Procedures also include directions to avoid incidents.

Safety can also come from smart design; systems that warn crew members

of missed inspection steps can be enough to save the ship. Internal

monitors that measure depth and speed can also warn the pilot when

procedures are not being followed properly.

Dangers and Accident Prevention

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Unmanned vehicles are a new technology that future submarines

could utilize. These miniature aquatic crafts would be used to search areas

by using onboard sensors, allowing them to gather information about

enemy locations and activities without being detected. Submarines might

even be able to launch unmanned aerial vehicles. These would be incredibly

efficient at collecting information about the location of enemy boats. Non-

combative submarines can also utilize unmanned vehicle technologies;

smaller submarines can be used to explore areas that were otherwise

unreachable. This would allow for the research of underwater caves and

crevices.

An unmanned vehicle being deployed from a submarine

The future developments of submarines are difficult to foresee, because technology is developing incredibly fast. A hundred years ago no

one thought nuclear power was possible, let alone capable of powering

submarines. The evolution of the submarine is remarkable. With advances

in current technologies, many exciting changes can be expected in the

future.

Future

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Mother ship: This is the vehicle that other smaller vehicles are dependent on for refueling or

transportation.

Buoyancy: Buoyancy is when the water pressure pushes back on a floating object. It keeps objects

above the surface of the water. Objects with low buoyancy do not float.

Ballast Tank: Ships have a compartment near the base called the ballast tank. These tanks contain

water, which lowers the center of gravity of the vessel and prevent tipping.

Hydrodynamic: An object that is hydrodynamic does not resist movement through a fluid, generally

water. Boats and submarines are designed to be hydrodynamic.

Sloop: A sloop is a ship, smaller than a frigate, used by the navy.

Unrestricted Submarine Warfare: The type of naval warfare where submarines sink shipping boats

without warning is considered unrestricted submarine warfare. In conventional warfare, the

submarines are supposed to allow the passengers leave the target ship before it the target is

sunk.

Wolfpack: This is the German U-boat strategy of massive attacks on single targets. It was used during

the Battle of the Atlantic in WWII.

Depth Charge: An anti-submarine explosive is known as a depth charge. They are dropped into the

ocean with a fuse that sets off the explosion at the correct depth. These are used to damage

submarines that are hidden underwater.

Uranium: The radioactive element that is used as fuel for nuclear reactors is uranium.

Fission: The nuclear reaction or decay of the radioactive substance is called fission. This process

releases energy that is harnessed by nuclear reactors.

Bulkhead: A bulkhead is a partition in the hull of a boat; typically ships have many bulkheads. They

separate the hull into multiple water tight compartments

Thermal Scar: As a nuclear submarine travels through the water, it leaves a trail of heat called a

thermal scar. It can be detected by thermal imaging systems.

Glossary

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Page 1: ashokachakra.blogspot.com Page 2: http://ffden-2.phys.uaf.edu/212_fall2009.web/Taylor_Duggar/Movement2.html Page 3: http://www.mercurymarine.com/propellers/about/how-propellers-work/ http://en.wikipedia.org/wiki/Pump-jet Page4: http://en.wikipedia.org/wiki/Submarine Page 5: http://en.wikipedia.org/wiki/Submarine Page 6: http://www.modelshipmaster.com/products/civil_war/index.htm Page 7: http://en.wikipedia.org/wiki/Submarine Page 8: http://www.onr.navy.mil/focus/blowballast/sub/work6.htm Page 9: http://www.u-35.com/prewar/ http://en.wikipedia.org/wiki/Torpedos

Picture Sources

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Page 10: http://ceweb2.uml.edu/FinalProjects/Jbarl50367/pics/ww1/uboats.html Page 11: http://en.wikipedia.org/wiki/Anti-submarine_warfare Page 12: http://www.istorya.net/forums/general-discussions/375584-i-400-submarine-aircraft-carrier.html Page 13 http://mitnse.files.wordpress.com/2011/03/nuclear_power_011.pdf Page 14: http://www.naval-technology.com/projects/barracuda/barracuda1.html Page 15: http://www.sqlskills.com/BLOGS/PAUL/post/Photos-of-the-USS-Silversides-WWII-submarine.aspx Page 16: http://en.wikipedia.org/wiki/USS_Skate_%28SSN-578%29 Page 17: http://en.wikipedia.org/wiki/Submarine Page 18: http://americanhistory.si.edu/subs/operating/aboard/damage/index.html

Page 19: http://en.wikipedia.org/wiki/McCann_Rescue_Chamber Page 20: http://inventors.about.com/od/militaryhistoryinventions/a/Military_Subs_

4.htm

Picture Sources

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Tony Trakadas is a student at the

Massachusetts Academy of Math and Sciences.

When he is not thoroughly enjoying school

work, he loves to bone up on history, or just lie

down and relax. He has a significant interest in

technology and unique inventions, and of

course, he really likes talking about ships.

Through writing this book, he hopes that

students can also be fascinated and awed by

something as simple as a submarine. And

above all he hopes everyone enjoys reading

Dive In!

Eric Williams also attends the Massachusetts

Academy of Math and Science. He wrote this

book to educate young minds. He hopes to

inspire children to not only learn more about

submarines, but to also become interested in

writing. Eric is greatly interested in the fields of

math and science. However, he still wants to be

a better writer, because writing is very

important for many other professions. Eric also

enjoys robotics and hope to make a career of it.

About the Authors

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