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Title: The Boys' Book of Submarines
Author: Collins, Virgil D., Collins, A. Frederick (Archie Frederick)
Language: English
As this book started as an ASCII text book there are no pictures available.
Copyright Status: Not copyrighted in the United States. If you live elsewhere check the laws of your country before downloading this ebook. See comments about copyright issues at end of book.

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[Illustration: _Courtesy of Leslie’s Weekly_









  _Copyright, 1917, by_
  _All rights reserved_



Submarine! It’s a word that’s in everybody’s mind—on every one’s tongue.

The very sound of it conjures up thoughts of great ships that were and
will be torpedoed and sent to the bottom of the old ocean to rust and
to rot there.

Of all the mighty monsters that ever sailed the seven seas this
piratical craft is by long odds the most daring as well as the most
dangerous to both life and property.

And yet while of course you know that a submarine can travel on or
under the water, dive like a porpoise and destroy an enemy ship by
shooting a torpedo at her, do you know exactly how an undersea boat
works and fights and just how she does all the seemingly impossible
feats for which she is notorious?

At the present time the greatest war in the world’s history is being
fought, and you are more than a mere looker-on for your country is in
it and you may be one of the boys who will be called to the colors to
defend her on, or against, these undersea craft.

If for no other reason than this you ought to follow not only the
battles as they are being fought on the east and west fronts of Europe,
but the warfare that is being waged by the submarines on the high
seas, for on these boats hinges to a very large extent the outcome of
the war.

Ever since the year of 1900 when five of the first really successful
submarines were built in the United States and sent to England the
value of this kind of war-craft has gone forward by leaps and bounds as
the devices for operating them were more and more improved.

Further too the submarine has played a far larger part in the war that
is now going on than the wildest fancies of her inventors of twenty
years ago could have pictured, much less believed, and what is of even
greater import she bids fair to become the champion fighter of the sea
in the future.

Indeed so wonderful is the submarine and so great are her possibilities
that you should by all means know exactly how she is made and works, as
well as her torpedoes. The easiest and certainly the most interesting
way to find out these things is to read this book and then build a
model submarine and torpedo according to the simple directions we have

To open the covers of this book and to read it is the next thing
to going through the hatch in the bridge of the conning tower and
examining the mechanism at first hand. So do it now.

    550 Riverside Drive,
      New York City.


  “A WORD TO YOU”                                       vii


   I. THE FIRST OF THE SUBMARINES                         1

    How the Submarine Came to Be.—The Development
    of the Submarine.—The First Submarine Boat.—A
    Submarine of the Revolution.—The First Torpedo Fired
    by a Submarine.—Robert Fulton’s Submarine.—The
    Earliest Steam Propelled Submarine.—The Coming of
    the Torpedo-Tube Submarine.—The Invention of the
    Electric Submarine.—What the Gas Engine Did for the
    Submarine.—The Two Types of Submarines.


    The Ballast Tank.—The Air Control Mechanism.—About
    the Power Plant.—The Pusher Control Device.—The
    Propeller-Shaft.—Installing the Motor.—Ballasting
    the Boat.—Making the Superstructure.—And Now the
    Conning Tower.—Setting the Propeller.—Putting on the
    Rudder.—Painting Your Craft.—How to Work Your Submarine.


    The Parts of a Submarine.—How the Hull Is Made.—What
    the Superstructure Is.—The Outside of the Conning
    Tower.—A Look Inside of the Hull.—A Peep into the
    Conning Tower.—Now the Navigating Compartment.—Next,
    the Diving Control Compartment.—The Four States of
    the Submarine.—How a Submarine Dives.—The Ballast
    Pumps and What They Do.—What the Buoyancy Tanks Are
    For.—Compressed Air and Air-Compressor Pumps.—Inside
    the Torpedo Compartment.—Why Trimming Tanks Are
    Used.—In the Mine Compartment.—And Last of All, the Sea
    Anchor.—Where the Crew of a Submarine Lives.

  IV. THE HEART OF THE SUBMARINE                       73

    What a Good Power Plant Is.—The Faults of the Steam
    Engine.—When the Gasoline Engine Came.—How the Gasoline
    Engine Works.—The Last Word in Submarine Engines.—Why
    an Electric Power Plant Is Needed.—The Dynamo-Motor and
    Storage Battery System.

  V. MAKING AND SHOOTING THE TORPEDO                   91

    The First Submarine Torpedoes.—How to Make a Model
    Submarine Torpedo.—The Body of the Torpedo.—Your
    Torpedo in Action.—How a Real Torpedo Is Made.—The
    Detonating, or Firing Mechanism.—The Engine that Drives
    the Torpedo.—How a Torpedo Is Shot at a Ship.—A Torpedo
    with a Cannon in It.

  VI. MAKING THE SUBMARINE DEADLIER                    115

    Arming the Submarine with Guns.—The Need of a
    Quick-Action Gun.—The Spring Action Gun.—The Compressed
    Air Action Gun.—How a Submarine Lays Mines.—Kinds of
    Submarine Mines.—How the Mines Are Made.


    How the Eye of the Submarine Got Its Name.—The First
    Submarine Eye, or Periscope.—How to Make a Simple
    Periscope.—The Modern Lenticular Periscope.—How the
    Telescope Is Made.—The Latest Type of Periscope.—The
    Limited Use of the Periscope.—The New Enemy of the


    The Tongue and Ears of a Submarine.—Kinds of Signaling
    Systems.—The Wigwag Way of Signaling.—The Flashlight
    System.—The Wireless Telegraph System.—Underwater
    Signaling Systems.—The Electric Current, or
    Conductivity System.

  IX. THE CREW OF THE SUBMARINE                       159

    Conditions on Early Submarine Craft.—When Crews Were
    Hard to Sign.—What the Base-Ship Is For.—How Men
    Are Trained for Submarine Duty.—The Complement of a
    Submarine.—Breaking in Raw Recruits.—The Conditions in
    War Time.

  X. HOW THE SUBMARINE ATTACKS                       171

    The Uses of the Submarine.—The Submarine as a
    Scout.—The Submarine as a Blockader.—How a Submarine
    Attacks a Merchantman.—When Submarines Attack in Pairs.

  XI. THE NEW SUBMARINE CHASERS                       185

    Schemes for Outwitting the Submarine.—Plans for
    Destroying the U-Boats.—Kinds of Submarine Chasers.—How
    the Chaser Chases a Submarine.—Shooting the Guns of the
    Chaser.—Submarine Air Chasers.—A Way to Lift the U-Boat

  XII. THE LAST WORD IN SUBMARINES                     199

    Uncle Sam’s Latest Submarines.—The Great Blockades
    of the Warring Nations.—The First of the Merchant
    Submarines.—Some Facts About the Deutschland.—How the
    United States Can Break the Blockade.—When Submarine


  A Modern American Submarine Cruising in the Afloat
      Condition with Foreward Diving-Rudders Folded
      Back against the Hull                            _Frontispiece_


  A “Baby Holland” Submarine, One of the First of the
      U. S. N.                                                    18

  Your Model Submarine in Action                                  46

  The Conning Tower and Navigating Compartment Controls
      of a Modern Submarine                                       58

  The Engine Room of a Modern Submarine Showing the
      Diesel Engines                                              82

  A Bliss Torpedo with Rotary Compressed Air Motor                98

  A 3½ inch Submarine Gun in Action Showing the Deck Well
      and Manner of Operation                                    118

  The Latest Type of Periscope. A much Magnified Image of
      the Object Is Shown in the Inner Circle, while in
      the Outer Circle Is Shown the Object Plus an “all
      round” View of the Horizon. A Submarine Fitted with
      This Periscope May well be Said to Have Eyes in the
      Back of its Head                                           136

  A Marine Wireless Installation                                 150

  The Crew of a Submarine (Note Sailor Going Below through
      Hatch in After-deck)                                       166

  A German U-Boat “Breaking Water” Preparatory to Examining
      the Cargo of an Enemy ship                                 178

  Three Eighty-Foot Gasolene Chasers on their Way to Patrol
      Duty                                                       188

  Navigating the “Deutschland” by Means of the Deck Control
      (Note Open Hatch Leading to Conning Tower)                 202




THE outcome of the great war that is now being waged in Europe hinges
largely on the ability of the Central Powers[1] to sink the ships of
the Allies[2] by means of _submarines_, and of the Allies to destroy
the enemy _U-boats_,[3] as the German submarines are commonly called.

Now, while a U-boat is a submarine, all submarines are not U-boats; for
the word _submarine_ means any and everything that lives, is done, or
works beneath the surface of the sea. Thus, a fish is a submarine, and
so is a boy while he is under water—though his clothes may be on the

=How the Submarine Came to Be.=—Yes, the fish of the _Paleozoic_[4]
era, see Fig. 1, was the earliest submarine, in that it moved in and
through the water under its own power, and that was millions of years
before the human race and the monkey tribe branched off from a common


Not only has the shape of the fish—or _ichthyoid form_, as it is
called—served as a model for inventors of the submarine boat to go by,
but the air-bladder in the fish, which aids it in keeping its place
below the surface of the water, finds its counterpart in the ballast
tanks of the modern submarine.

When the first real boy parted from his monkey cousin—that is, when the
boy came down from his tree-top house and left the monkey up there to
eat a banana all alone—Nature had fitted him with long legs and flat
feet so that he might swiftly run away from his enemies on land.

But in those days when the earth was young there were not only
gigantic, long-necked animals with cross-cut saw tails and cunning
little heads, but terrifying winged lizards[5] flew around everywhere
like airplanes do now, and monstrous and inconceivable things swam in
the sea. He could easily outwit and outdistance his animal foes on
land, but he could not fly away from those that sailed the air, nor
could he venture far into the water for fear of his aquatic enemies.
But he learned to swim in spite of them and when he could dive down
here and come up over there he became the second submarine. (See Fig.


From the time he learned to swim and grew to be a man he nursed the
idea of making some kind of device that he could get into and swim
about with, not only so that he might be protected from the monsters
that sought him as food but that he might destroy them as well.

And even after all the prehistoric beasts became extinct and so were
no more on the face of the earth to menace his safety, he still kept
thinking over the idea of the submarine, and it kept getting stronger
within him as the _convolutions_ of his brain grew deeper.

=The Development of the Submarine.=—By hard thinking and long
experimenting, and the other way about, and always working to the end
that he might invent some kind of boat by which he could travel under
and through the water (or, as the French have it, _sous marin_—_sous_
meaning _under_ and, of course _marin_ means _sea_) like the swiftest
of fish and quite as easily.

His reason for wanting a submarine boat now that the animals he had so
feared in the past had disappeared, was to find treasure ships that had
sunk to the bottom of the old ocean, or, more likely because it seemed
more practical, to attack, unseen and without warning, merchantmen that
carried precious cargoes—in a word, he would a submarine pirate be.

But like everything else that needs mechanical devices and electrical
apparatus the development of the submarine from the first crude
attempts to the powerful and perfectly controlled U-boat as we know it
to our sorrow to-day took many men working through many years to make
it sea-worthy and practical.

In each one of these inventors the thought that ruled him was to make a
boat which would sink or swim, as he wanted it to; and though none of
the earlier workers succeeded in building a really good submarine, it
was not their fault but their misfortune, for the vital mechanical and
electrical appliances they needed had yet to be invented.

But the efforts of each one of these pioneers served as a
stepping-stone to the building of the first practical boat, in 1901,
which could be used successfully as an undersea destroyer. This was the
_Holland_, which you will read more about presently; and the British
Admiralty purchased five of the first ones built.

=The First Submarine Boat.=—Away back there in the very year when the
Pilgrims landed from the _Mayflower_ on Plymouth Rock—that is to say,
in 1620—a Dutchman named Van Drebel, who happened to be living at that
time in England, worked out the idea that originated in the brain of
his prehistoric ancestor, and that was to build a submarine boat.

Of course in those days there were no such things as steel boats, nor
had engines to propel them been invented, but men were adept builders
of wooden boats and, as much or more to their credit, they were past
masters of the art of sailing them.

But the lack of steel, of engines, and of other recent inventions
didn’t daunt the dauntless Van Drebel in the least; for he went right
ahead and built his underwater craft of such materials as he could
get hold of. His submarine was nothing more nor less than a regular
wooden boat which was completely decked over, covered with leather, and
smeared with tallow to make it watertight.

The submarine was propelled through the water by means of a pair of
oars on each side as shown in Fig. 3, very much in the same fashion as
were the far-famed Grecian galleys of old; but in this boat the oars
passed through watertight flexible covers fastened over the portholes.

A hollow mast was _stepped_ into the deck to supply air to the crew
when the submarine was under water, and it was also used to spread a
little canvas on when the boat was running afloat and the wind was good.

[Illustration: FIG 3. VAN DREBEL’S SUBMARINE.]

Now, you may think this submarine of Van Drebel’s was a mighty crude
attempt, and no one will say you nay, but just bear in mind, please,
that it was the _granddaddy_ of the modern submarine and that it
traveled submerged down the Thames River, carrying in it no less a
personage than King James the First, and covering a distance of seven
miles from Westminster to Greenwich.

After this first and very successful attempt at submarine building
it was not long until others began to make improvements and to build
underwater boats which would outdo the spectacular performance of Van
Drebel’s submarine. It ought to send a thrill of pleasure through
you to know that most of these inventors were Americans, but in your
feeling of pride don’t forget that the oversea workers along submarine
lines followed closely on the heels of our own in ingenuity, building,
and operative ability.

=A Submarine of the Revolution.=—The first submarine designed to
destroy enemy ships was invented and built by an American named David
Bushnell, just about the time that Liberty Bell was ringing out the
Independence of the United States.

His submarine, had it not been for an accident, and of which I will
tell you later, would now be exploited in every school history of our
country. But even the accident showed that the submarine had great
inherent possibilities and dynamic power stored up in it which warring
nations of the future must reckon with.

Different from all past ideas and present conceptions of submarines,
and far removed from any design which is ordinarily thought of in
connection with boats, Bushnell’s submarine, instead of going through
the water with its _long axis_ horizontal to the top, moved through it

The way in which this strange craft was _submerged_—that is, sunk—is
_fundamental_, which means that it is the simple, natural way and the
one that is used in all submarines that have been built since then.

A number of empty tanks were so fixed in the vessel that when the pilot
wanted to submerge it he could let the water into them, and when he
wanted to rise to the surface again he could pump the water out with a
hand force-pump. This scheme is used in all of the submarine boats of
the present time, though of course the pumps are power-driven.

A heavy weight that could be detached was fixed to the bottom of the
craft, which helped it to maintain its upright position and also aided
in submerging it. In case an accident happened to the pumps the weight
could be released, when the craft would come to the surface.

Another good feature of this submarine was the valves which let fresh
air into the vessel when it floated on top of the water but which
closed _automatically_—that is, without the help of the pilot—when the
submarine sank below the water line.

The way the first submarine of Bushnells was driven was just as
primitive as the one built by Van Drebel; indeed, it was a shade worse,
for a solitary oar sticking through the rear end of the shell provided
the means for going ahead while another oar on one side helped to raise
and lower it.

He later designed, built, and successfully operated another submarine,
which was far superior to his first model. It had the same shape as
his first one but it was propelled by two screws which were turned by
_hand_; one of these moved the submarine forward and backward through
the water, and the other one moved it up and down—all of which is
clearly shown in Fig. 4. Hence the credit for the invention of the
screw-driven submarine belongs to Bushnell.

[Illustration: FIG. 4. BUSHNELL’S SUBMARINE.]

=The First Torpedo Fired by a Submarine.=—Bushnell, though, did more
than to invent a workable submarine, for he also devised and used a
_torpedo_; or it would be better to call it a _bomb_, since it was
_timed_ to explode by clock-work, instead of by _concussion_. He
intended to hang this submarine bomb on the bottom of an enemy ship—and
thereby hangs a tale.

The British man-of-war _Eagle_ had anchored in New York Harbor close
to Staten Island sometime in the famous year of 1776.

The inventor was a patriot and offered his services and the use of his
submarine to the new United States Government; the latter accepted them
and ordered him to blow up the warship. As the inventor became sick
he gave a sergeant, named Lee, the honor of using his submarine and
blowing up the ship. Lee worked the submarine without a hitch until he
reached the man-of-war, and then his troubles began.

Try as he would, he could not drive the screw into the tough English
oak of which the hull of the ship was made, and this he must needs do
in order to fasten the bomb to the bottom of it.

Finally, just as the clock-work of the torpedo was about to explode it,
he set it adrift, and the young officer made off just in time to save
himself. As it was, the bomb exploded close to the stern of the boat,
but it did not do any serious damage.

=Robert Fulton’s Submarine.=—About the year 1800, Robert Fulton, the
Famous American inventor, who built the first successful steamboat,
designed and built a submarine that was far ahead of either of those I
have just described.

It was cigar-shaped, to begin with, and this lessened the resistance
it offered to the water, and it was fitted with a keel, a rudder, a
propeller, and a _conning tower_, so that the pilot could see where he
was going. Fulton did not attempt, though, to use a steam engine to
drive the propeller, but turned it by hand. His submarine is shown in
Fig. 5.

Another big improvement that Fulton made was to cover the hull of
his submarine with copper plates. Taken altogether it came as near
being a real submarine as could have been made with the materials and
inventions which were available at that time.

[Illustration: FIG. 5 FULTON’S SUBMARINE.]

After offering his submarine to the French, British, and American
Governments in turn, and after it was _turned down_ by all of them
because they failed to see in it a useful weapon of war, Fulton turned
his thoughts toward home and craft of a more peaceful nature.

Had any one of these governments been able to see the wonderful
possibilities of the undersea craft that Fulton had so greatly improved
upon, the submarine would have been perfected long before it was.

Fulton’s remarkable experiment, with his _Nautilus_, as he called his
boat, on the Seine River, which flows through Paris, attracted much
attention, and a plan was set on foot to use his submarine to rescue
the exiled Napoleon from the Island of St. Helena. Again Fulton was
doomed to disappointment, for the Great Emperor died before the scheme
could be carried out.

It was then that Fulton returned to the United States and set about the
more peaceful task of building a steam propelled river boat, or _steam
boat_ as it is called, and which won for him much money and undying

=The Earliest Steam Propelled Submarine.=—It was eighty years after
Fulton made his classic underwater experiments that Garrett, an English
inventor, designed, built, and operated a submarine which used steam as
its source of power.

This later submarine had all the good features of Fulton’s craft,
besides the history-making improvement of using a steam engine to drive
her—not only when she was afloat but when she was submerged as well.

The way it was done was like this: a regular boiler was set in the
boat and this had a telescopic _funnel_, as a ship’s smoke-stack is
called. When running on the surface the water in the boiler was changed
into steam and the smoke poured out of the funnel. But when the craft
was submerged, the funnel was drawn under the deck, the fire doors,
which were made air tight, were closed, and the steam pressure already
generated in the boiler was high enough to run the boat for several

=The Coming of the Torpedo-Tube Submarine.=—Clear up to the time of the
_Centennial Exposition_ held at Philadelphia in 1876, the only idea
that inventors of submarines seem to have had was to use a bomb of some
sort which could be attached to the submerged hull of an enemy ship and
which would blow her up.

This crude scheme, as you have seen, was not only uncertain but it was
at once a difficult piece of work and very dangerous to the operator.
About this time, or perhaps a little later, a Swedish engineer, named
Nordenfelt, invented a torpedo which could be shot from a tube in the
head of the submarine.

His early submarine had a length of 100 feet and could make 12
_knots_[6] on top of the water; she could be submerged to a depth of
about 50 feet, when, of course, her speed was considerably reduced. She
was steam-driven and had two propellers.

But the great improvement of this submarine craft over all the others
that had been built before her was her torpedo tubes through which
torpedoes[7] could be shot from the inside of the boat and aimed at
the enemy. Besides the torpedoes, she carried two rapid-fire guns, and
these made her an engine of destruction greatly to be feared. She is
shown in Fig. 6.

=The Invention of the Electric Submarine.=—What with the amazing uses
to which electricity was being put, it is small wonder that as soon as
the storage battery was invented and electric motor was discovered,[8]
inventors became imbued with the idea of using the mighty invisible
power for running their submarine boats.


The first submarine to be propelled solely by electricity was designed
and built about 1886 by Campbell and Ash, of England. The outstanding
features of this undersea craft were the storage batteries, which were
formed of 104 cells, and the electric motors, of which there were two
and each one developed 45 horsepower.

The boat had a speed of 6 knots, and it had a cruising radius of 80
miles, without recharging the batteries. She is shown in Fig. 7. The
electric submarine never got out of the experimental class, because of
the imperfections of the storage battery at that early date and in
virtue of the fact that its range of travel was very limited.

But the experiments were not without value, though, for they led to the
use of electricity as the ideal power for undersea propulsion, as you
will presently learn.


=What the Gas Engine Did for the Submarine.=—Greater effort to use
electricity as a motive power for submarines would doubtless have been
made had not the gas-engine been invented in 1888.

This new kind of engine was the ideal motive power for propelling a
submarine on the surface of the sea, and at the same time it could
drive a dynamo which would generate an electric current to charge the
storage batteries with.

And when the boat was submerged the engine could be stopped and there
was no smoke or burnt gases to escape; the storage battery then gave
up its electric current, this energized the motors, and these in turn
drove the propellers. This combination system of gas and electric power
is used in all submarine boats at the present time.

The first engineer to combine a gas and an electric power plant in a
submarine as described above was Depuy de Lôme. This French engineer
turned out a wonderfully successful submarine; and this was still
further perfected by another Frenchman, named Gustave Zédé. Many of the
submarines used in the French Navy at the present time are of the Depuy
de Lôme-Zédé type.

=The Two Types of Submarines.=—Two American inventors, name Lake and
Holland, were working _independently_ of each other—that is, neither
knew the other was working on submarines—and each developed a different
type of undersea boat. This was about 1896.

_The Lake Submersible._—The first underwater boat built by Simon Lake
was shaped very much like a ship. The hull was mounted on wheels, so
that it could travel on the bottom of the sea if need be, for it was
originally intended to be used by pearl divers and oystermen.

In the early part of this chapter I told you that the word _submarine_
means anything that lives in, is done, or works beneath the water-line
of the sea. Now, in naval engineering, _submarine_ has come to mean
an undersea craft that can _dive_, while an undersea boat that simply
sinks on an even keel is called a _submersible_. So the Lake shown in
Fig. 8 is a submersible, for it is not intended to dive.

_The Holland Submarine._—The Holland undersea boat is a real submarine,
for it can dive. The hull of this boat looked more like a whale with
its tail twisted up than like a boat, as you will see in Fig. 9.




[Illustration: _Courtesy of Leslie’s Weekly_


_The Combined Holland and Lake Types._—The shape of the Holland
submarine makes it a good undersea boat; the Lake submersible has a
large deck and roomy quarters, and its shape makes it good for surface
going. The result is that naval architects have combined the two types
so that the new model submarines have the advantages of the older types
and are without their disadvantages.

Nearly all of the boats of the submarine flotilla of the United States
Navy are of the Holland and Lake types combined, as shown in Fig. 10.
You will find more about these craft in another chapter.



Complete Instructions and Working Drawings for Building a Two-Foot
Model Submarine



THE best way to know how a machine works is to work with it, and the
next best thing to working with an actual machine is to work with a
model which you have made with your own hands.

In this way you not only will become acquainted with the mechanism
which is used to obtain a certain result, but if you are of an
inventive turn of mind you are likely to get one or more ideas for
improving it which will be of more or less value.

Now, this is just what you should do with the submarine if you really
want to know the innermost secrets of how it is made and works—that is,
you should build a model of one and experiment with it.

To the end that you may do this, I have given in this chapter the
_plans_ and _specifications_, which mean the working drawings and a
full description, of a 2-foot model submarine boat which you can easily
make and run yourself.

This model submarine is not only instructive but it is “amoosin’,” as
Artemus Ward used to say, for while it starts out _awash_—that is, with
its deck just about level with the top of the water—it will soon take
a dive, run a ways _submerged_, and then bob up on the surface again,
just like a real submarine.

=The Parts of the Model Submarine.=—There are only four chief parts to
this model, and these are (1) the _hull_; (2) the _ballast tank_; (3)
the _power plant_; and (14) the _superstructure_. All of this is shown
in Fig 11.

The hull is of course the body of the boat. The ballast tank is a tin
can in the bottom of the hull; when it is filled with water the extra
weight makes the boat sink, and when the water is blown out of it by
compressed air it makes the boat rise to the surface again.

The power plant includes an electric motor, the batteries to run it,
the propeller-shaft and propeller, the pulleys which work the valve
that lets the compressed air flow into the ballast tank to blow out the
water, and finally the superstructure, which consists of the deck and
the conning tower, though in this case the latter is made to hold the
compressed air.

=The Hull of the Boat.=—The first thing to do is to make the hull; and
the easiest way to build one that is light, strong, and watertight is
to whittle out, or have sawed out, two tapering pieces of wood as shown
at _A_ and _B_ in Fig. 12. The faces are shown by the dotted lines at
_C_ and _D_ in Fig 11.

These are for the nose and tail blocks, as we will call them, and each
one is 14½ inches long. The other dimensions, as well as the shapes of
these blocks, are also shown in Fig. 12.


Bore four ⅛-inch holes, ¾ inch deep in the _faces_—that is, the flat
ends of each block—at the places shown by the little circles; these
are to take in the ends of the _brace rods_. Next bore a ¼-inch hole
lengthwise through the tail block as shown by the dotted lines at _B_.
Bore out this hole with a 1-inch bit to a depth of ¾ inch, to form a
_stuffing box_.

[Illustration: FIG. 12. THE NOSE AND TAIL BLOCKS.]

Now cut off a piece of brass tube which has an inside diameter of ⅛
inch and an outside diameter of ¼ inch and force it into the hole in
the tail block; this tube forms the bearing for the propeller-shaft.

Cut out a disk of brass 1¼ inches in diameter and 1/16 inch thick;
drill a ⅛-inch hole through the center of it for the propeller-shaft to
pass through, and three ⅛-inch holes at equal distances apart near the
edge, as shown at _C_, so that it can be screwed to the tail block. The
purpose of this disk is to keep the _packing_ in the stuffing box. See
Fig. 12.

The next thing to do is to cut off two brass rods each ⅛ inch in
diameter and 16½ inches long and fit the ends of these into the lower
holes in the blocks; and then cut off two more brass rods 17 inches
long and set these into the upper holes. Bend these latter rods out a
little until the faces of the blocks are parallel with each other, and
you will have a substantial framework on which to fasten the _skin_ of
the hull.

The skin, as the sheets or plates which form the hull are called,
is made of sheet tin, and to cut the tin you should have a pair of
tinner’s shears.

You will need seven strips of tin altogether: one for the bottom and
three for each side. The sizes and shapes of these strips are shown
in Fig. 13. The widest strip is used for the bottom of the hull; bend
up the edges along the dotted lines, then punch eight holes in the
ends—these are shown by the little crosses—and screw it to the nose and
tail blocks with flat-headed wood screws.

Next punch holes in and screw one of the lower strips to each side of
the nose and tail blocks, with the hollow curved edge down and lapped
over the turned-up edge of the bottom strip; punch and screw on each of
the middle strips, with its lower hollow curved edge over the top of
each of the lower strips; and then punch and screw on the top strips.

When you have the bottom and all of the side strips screwed on, each
one will lap over the next lower one ½ inch and fit snugly up to it,
and at the same time they will all curve gracefully.


After you have these strips screwed on, you must solder the lap seams
to make them watertight. You can easily do this by using a regular
tinner’s soldering copper—a soldering fluid made by dissolving zinc
clippings in some dilute _muriatic acid_—and what is called _wire

The cover of the boat, or _deck_, to give it its nautical name, is a
part of the superstructure, and you can cut this out later on.

=The Ballast Tank.=—The sole purpose of the ballast tank is to add
enough weight to the boat to sink it when you want it to sink.

Use heavy sheet tin for the tank. Cut out two strips, each of which is
2 inches wide and 15½ inches long. Make a ½-inch lap seam and solder
the ends of this strip together, making one strip 30 inches long. Bend
the strip so that each side is 11 inches long and the ends are 3½
inches long; this will bring the ends together, forming another ½-inch
lap seam, and this, of course, you must also solder.

[Illustration: FIG. 14. HOW THE BALLAST TANK IS MADE.]

Cut out a top and a bottom, each 4 inches wide and 11½ inches long.
Cut the corners; bend up the edges ¼ inch all round, and solder the
corners. And don’t be afraid to use plenty of solder, for this tank
must be strong, and not only watertight but airtight as well.

About 4 inches from one end of the bottom sheet cut a ½-inch hole for
the _water inlet and outlet_, that is the hole where the water flows
into and out of the tank. In this hole solder a piece of ½-inch brass
pipe ½ an inch long and flush with the surface of the tin, as shown at
_A_ in Fig 14; and also at _B_ in Fig. 11.

Now, with a pair of dividers 1¾ inches in diameter, _scribe_ a circle
which has its center 3¼ inches from the other end of the bottom and in
the middle of it. Cut out three strips of tin ¼ inch wide and 2 inches
long—or wire will do—and bend over one end of each one ¼ inch.

Solder these strips to the bottom at equal distances around the
circle as shown by the dotted line at _B_ in Fig. 14, and in the
cross-sectional drawing Fig. 15. The upright strips serve as guides to
keep the _cork float_ in place and yet let it move freely up and down
in the tank.

Cut a hole ½ inch in diameter, 2 inches from one end of the cover, or
top, of the tank as shown at _A_ in Fig. 14. This is for the pipe of
the valve mechanism.

Next cut out a hole exactly ¾ inch in diameter, and have its center
3¼ inches from the end. Take a piece of tin and make a _valve seat_
so that its small end is 9/16 inch in diameter and solder it to the
top over the hole. This valve seat must be made with particular care,
so that it will be perfectly smooth and the _valve plug_ will fit it

The valve plug is a piece of cork cut in the shape of a cone and must
fit the valve seat exactly; soak it in machine oil, then run a piece of
aluminum wire 1¾ inches long through it and bend it over on the bottom
as shown at _C_ in Fig. 14 and in Fig. 15.


Next solder the bottom to the sides of the tank. Drop the cork float
between the upright guides as shown at _B_ in Fig. 14. Set the cork
valve plug on the cork float. Put on the cover with the aluminum wire
sticking up through the hole in the valve seat; and finally solder on
the cover.

=The Air Control Mechanism.=—Since you cannot be in your model
submarine when it is stealing along submerged through the water,
you must fit an automatically controlled air-valve in the pipe that
connects the air chamber with the ballast tank, in order to blow out
the water when it is time for the craft to come to the surface to
breathe again.

There are two chief parts to the air control mechanism, and these are
(1) the _air-valve_, and (2) the _pusher control_. We will describe the
air-valve and its fittings now and tell you how the pusher control is
made and works under the next caption.

_The Power Plant._—The reason we have split up the air control
mechanism in this fashion is because it is easier to solder the air
supply pipe to the ballast tank at this stage of the work than it is to
do it after the ballast tank is fixed to the bottom of the hull; again
it is easier to do the latter job before the power plant is put in the
hull; and finally the pusher control is really a part of the power

If you will take a good look at the cross-section drawing, Fig. 15,
you will see that the air-valve and its fittings consist of (a) the
air-valve proper; (b) a small piston; and (c) the connecting pipes.

First get four lengths of pipes[9] all of which have an inside
diameter of 5/16 inch; have these pipes ½, 2, 2⅜ and 2¾ inches long
respectively. Thread or have these pipes threaded as follows: the
½-inch length threaded inside and all the way through; the 2-inch
length of pipe threaded on the inside to a depth of 1 inch from one
end and a hole drilled in it ⅝ inch from the other end, and have this
threaded; the 2⅜-inch pipe threaded on both ends and one end bent over
⅝ of an inch; and, finally, thread one end of the 2¾-inch length of

Now screw the ½-inch length of pipe on the end of the 2⅜-inch piece of
pipe which has the nut and washers on it. Screw a bicycle tire valve
into the 2-inch piece of pipe and far enough in so that the bent end of
the 2⅜-inch pipe can also be screwed in, as shown in Fig. 15. Last of
all, screw the end of the 2¾-inch pipe into the threaded hole in the
wall of the 2-inch pipe.

Next make a piston of a piece of brass rod ⅜ inch long and of such
diameter that it will fit snugly and yet slide easily in the end of
the 2-inch pipe. Drill a 1/16 inch hole through the piston and fix a
stem in it tight so that it projects ¼ inch through one end and ⅜ inch
through the other end. File a grooved ring around the piston to hold in
the oil and slip the piston in the open end of the pipe.

This done, clean the lower end of the long pipe well; set it into the
hole in the top of the ballast tank; use plenty of soldering fluid and
solder it in good and tight. At the time you are doing this job see to
it that the long pipe sets _plumb_—that is, perfectly straight up and

_Setting the Ballast Tank in the Hull._—You are now ready to set the
ballast tank in the hull. To do this you must cut a hole ½ inch in
diameter, 4 inches from the face of the nose, as shown at _B_ in Fig.
11. Set the tank in the hull so that the pipe on the bottom of it will
stick through the hole which you have just cut; and then solder the
pipe to the hull on the outside.

_Putting in the Bulkhead._—As you will see from the end views _C_ and
_D_ in Fig. 11, there is considerable space between the ballast tank
and the skin of the hull on both sides.

As melted lead is to be poured into this space to give the boat
the right weight to make it sink properly a _bulkhead_—that is, a
partition—must be cut out of tin and soldered to the hull, on the
inside of course, up against the rear end of the ballast tank. The face
of the wooden nose against which the ballast tank rests will keep the
lead from running out at the front end. As the lead is poured in after
the motor is set in place this operation will be described later.

=About the Power Plant.=—While in a real submarine the _power
plant_—the machine that converts the fuel into power to drive the
boat—is a _gas engine_ when it is cruising on the surface, and a
_storage battery_ and an _electric motor_ when it is running submerged,
in your model it is electricity first, last, and all the time.

That is to say, a battery of dry cells supplies the current to run an
electric motor and this in turn drives the propeller; besides, it also
furnishes the power needed to work the pusher which controls the air
supply through the bicycle valve which I have just explained to you.

The first thing to do toward getting the power plant is to beg, buy,
or borrow a small electric motor which will develop not less than 1/30
horsepower and at the same time run on a battery of not more than 3 dry

While the motor can be run to its full capacity on two dry cells it
will develop more power on a three-cell battery. Now, to get three dry
cells which will fit into the small space that is left in the hull of
your model you will have to use rectangular cells.[11]

You will also need a small switch to open and close the battery
circuit, and this is fixed to the top of the boat, or _deck_ as it is
more properly called; the way it is put on will be explained under the
caption of _The Superstructure_.

When you want to buy one of these switches ask for a _porcelain base,
single pole, single throw switch_. It will cost about a quarter. The
way the dry cell battery, the motor, and the switch are connected up is
shown in Fig. 16.


=The Pusher Control Device.=—Before the motor is installed in the hull
the pusher control device which opens the compressed air valve must be
made and mounted on top of it.

On top of the motor, as you will see by looking at Fig. 16, there is a
metal name plate, which is fastened to the top of the field magnets by
four screws; unscrew the latter and take off the plate.

Now make a _pillow block_, as the bearing for the threaded spindle is
called. Saw out with a _hack saw_[12] a base plate of sheet brass ⅛
inch thick, 1 inch wide, and 1½ inches long; drill four ⅛-inch holes in
the corners of the plate, so that it can be screwed down to the field
magnets of the motor.

Also drill two ⅛-inch holes lengthwise in the middle of the plate and
have the first one ⅛ inch from one end and the other ½ inch from the
same end and in a line with the first hole.

Take a brass bar ¼ inch thick, ½ inch wide, and 1⅝ inches high, and
drill two 3/32 inch holes in one end of it, to correspond to the two
holes in the middle of the base plate, and thread these to fit a couple
of 6-32 machine screws.

Next drill a ⅛-inch hole clear through the top of the bar, or
_standard_, as it is now called, 3/16 inch from the top. This must
be _very accurately done_, in fact, it ought to be done with a drill
press, for if it is not precisely at right angles to the base, the
spindle will not run true, and besides there will be a great loss of

Drill a hole through the top of the standard until it meets the hole
through which the spindle is to pass, and by means of this top hole
keep the spindle well oiled. The pillow block is shown complete in
Figs. 15 and 17.

To make the spindle, get a piece of soft steel rod ⅛ inch in diameter
and 4½ inches long. Thread it from one end to within 1⅜ inches of the
other end, and screw on a nut as far as it will go. Push the smooth end
through the hole in the pillow block; slip a collar over the end close
up to the standard, and screw it fast. To make the pusher mechanism
complete put a grooved pulley 1½ inches in diameter on the end of the
spindle up close to the collar and screw it fast.[13]

[Illustration: FIG. 17. THE PILLOW BLOCK.]

The last part of the pusher control is the pusher itself. It is simply
a round brass rod ¼ inch in diameter and ¾ inch long, with a hole
drilled through it lengthwise and threaded to fit the spindle. Solder a
bit of brass near one end, to make it heavier on one side than on the

Now, when the motor is set in place in the hull and its small pulley
is belted to the large pulley on the spindle and the current is turned
on, the spindle revolves, but the weight on the pusher will keep it
from turning with the spindle. Instead, the curious result is that it
screws itself toward the free end of the spindle, and when it reaches
the end, the hollow pusher goes over the stem of the piston. When it
strikes the piston it pushes on it until it presses the other end of
the stem against the pin of the bicycle valve and this opens it.

If you will keep the piston, the pusher, and the bearings well
lubricated with sewing-machine oil, there will be little power lost
through undue friction. But you must be careful not to get any oil
on the _commutator_ of the motor, for this will keep it from running

=The Propeller-Shaft.=—Before you install the motor you must put the
propeller-shaft through its bearing in the tail block.

To make the propeller-shaft, get a piece of soft steel rod ⅛ inch in
diameter and 5¼ inches long and thread it at both ends. Slip it through
the tube which forms the bearing. Soak some cotton-waste in machine
oil and pack it in the stuffing box in the tail block. Now screw the
circular plate to the face of the tail block to keep the packing in

=Installing the Motor.=—While we have given you the height to make
the pillow block, it will, of course, depend on (1) the height of the
motor, and (2) the height of the center of the piston when both are
measured from the floor of the hull; this is because the pusher spindle
and the piston stem must be exactly in a line with each other.

Another thing: The motor we have shown is 3 inches high from its base
to the center of its armature shaft; but the motor you get may not be
of this height. While it can’t be any higher than 3 inches unless you
change the design of the boat, it can be shorter if you mount it on a
block of the right thickness.

Before installing the motor in the boat, see that both pulleys are
in a line with each other, and put on a belt. Thread the end of the
motor-shaft and fit a _coupling_ to it so that the propeller-shaft can
be screwed into the other end. To make the coupling take a piece of
brass rod ¼ inch in diameter, 5/16 inch long; drill a 3/32-inch hole in
it, and thread it to fit the motor- and propeller-shafts.

Screw the coupling on the motor-shaft. Mount the motor on a board of
the right thickness, and set it in position in the hull. Screw the
propeller-shaft into the coupling, and be sure to have the motor set so
that the shafts are in perfect _alignment_—that is, in a line with each
other—as shown in Fig. 15.

Unless this is done the propeller-shaft will bind in its bearing and it
will take a large part of the power of your motor to overcome it. When
the motor, the pusher spindle, and the propeller-shaft all spin freely
on closing the battery circuit, you can then secure the motor to the
floor of the hull with a couple of machine screws as shown in Fig. 15.

=Ballasting the Boat.=—The next thing to do is to _ballast_ the boat by
pouring melted lead into her hull to make her sink deep enough in the
water to balance her and to make her submerge entirely when water is
let into her ballast tank.

The way to do this is to cork up the hole in the pipe in the bottom
that leads to the ballast tank and then set the boat in a tub full of
water. Now lay the battery cells in the positions they are to occupy
in the boat, as shown at _B_ and _C_ in Fig. 11, and see how far up
the water-line comes on the hull—or, in other words, how deep the hull
sinks into the water.

Next pour melted lead in between the sides of the ballast tank and the
hull while the boat is still in the tub of water and distribute it so
that the boat floats on a perfectly even keel. When you have poured
enough lead into the hull to make her sink to within an inch or so of
her _gunwales_ (the upper edge of the boat’s sides) and she is nicely
balanced, let the lead cool, take the boat out of the tub and put her
back on her stocks on your bench.

And now a couple of parting hints: (1) You can melt the lead in an iron
ladle over a kitchen fire, and (2) put a little water in the ballast
tank so that the hot lead will not open the soldered seams.

=Making the Superstructure.=—This consists of the top, or deck, and the
conning tower, which in this model serves for the compressed air tank.

To make the deck, cut out a sheet of heavy tin the exact shape of and
dimensions given in Fig. 18. Cut a ½-inch hole half way between the
ends, and in the middle, for the air-valve pipe to pass through and
which is screwed to the conning tower as shown in Fig. 15.

Cut out a 2½-inch hole in the aft end of the deck for a _hatch_, and
make a cover, or hatch, for it 3½ inches in diameter; this hatch will
allow you to get your hand through the deck and into the hull to reset
the pusher device when your submarine is to make another trip.

[Illustration: FIG. 18. HOW THE DECK IS MADE.]

Cut out a rectangular hole ½ inch wide and 2 inches long in the for’ard
end of the deck, for the screws and the wires of the switch to pass
through. Screw the porcelain block of the switch to a board of the same
size, with the tin deck in between them; this insulates the screws of
the switch from the tin, which would otherwise _short circuit_ the
battery and run it down. Run sealing-wax in and around the edges of
both the porcelain and wood blocks to make a watertight joint, for
water must not get into the boat.

This done, connect up the batteries and these with the motor, with
heavy rubber-covered copper wire, and connect the battery and the motor
with the switch with flexible electric-light cord. Set the deck on the
hull; and if you are sure everything is in first-class working order,
solder it on tight. If, though, you are not quite certain, you can do a
temporary job by putting it on with sealing-wax.

Supposing you are young enough to have imagination or old enough to
have dim vision, the switch mounted on the deck will look very much
like a gun that is just coming through the hatch and getting ready for

=And Now the Conning Tower.=—The conning tower is an airtight vessel—as
far as your model goes—having a conical shape.

To make it, scribe two circles, using the same center, on a sheet of
heavy tin, making one of them 4 inches in diameter and the other 5
inches in diameter, and cut it out around the larger circle.

Cut a ½-inch hole in the center of the disk. Put the ½-inch length of
threaded pipe we told you about under the caption of _The Air Control
Mechanism_ in the hole, and solder it fast. Cut the edge of the disk
_radially_ with your shears, from its edge to the smaller scribed
circle, and then you can bend up the edge all the way round.

Next cut out an _arc_ of tin of the size marked and the shape shown in
Fig. 19. Make a lap seam and solder it.

Scribe a 3-inch and a 4-inch circle on a piece of tin and cut it out.
Cut the edge radially as before, and bend it up all the way round. Cut
a ½-inch hole near the edge of the intake air-valve pipe. Solder the
two disks to the cone and be sure the ½-inch threaded pipe is _inside_.


To complete the conning tower, get a 5- or a 7-inch length of pipe;
bend over one end a little; thread it and screw in a bicycle valve.
Finally stick the other end of the pipe through the hole in the top of
the conning tower and solder it there, as shown in Fig. 20, which also
shows the conning tower complete. The purpose of this pipe is so that
you can pump air into the tank with a bicycle, or an auto pump.

Screw the conning tower on the end of the pipe of the air-valve
mechanism which projects through the top of the deck, and then you are
ready to do something else.


=Setting the Propeller.=—A 2½-inch brass propeller with three blades
can be bought for about 40 cents of Luther H. Wightman and Co., 132
Milk Street, Boston, Mass.

This little propeller has a hub diameter of 5/16-inch, as shown in Fig.
21. When you get it, drill a 3/32-inch hole through the hub and thread
it; screw it on to the end of the propeller-shaft, and then screw on a
nut to hold it on tight. (See Fig. 22.)

=Putting on the Rudder.=—And last of all comes the rudder. Cut off two
pieces of ⅛-inch brass rod 4 inches long; thread one end of each rod
down 1 inch, and sharpen the end a bit; thread the other end of each
one down ⅝ inch and screw a nut on it.

[Illustration: FIG. 21. THE BRASS PROPELLER.]

Drill two 3/32-inch holes in the tail block in a vertical line with
each other 4⅜ inches apart, and screw in the brass rods as shown in
Fig. 22. Cut the rudder out of heavy tin—or, better, 1/32-inch-thick
sheet brass—the size and shape shown also in Fig. 22.

[Illustration: FIG. 22. THE RUDDER AND PROPELLER.]


Bend the end of each tongue of the rudder to make a _knuckle_, and
slip the knuckles over the pins. Screw a nut on the end of each pin,
and by tightening them up you can make the rudder stay at any angle you
put it.

=Painting Your Craft.=—You can buy a good marine paint of almost any
color you want at paint stores generally.[14]

Gray is the most appropriate color to paint your model craft with; but
whatever color you choose, lay it on the long way of the boat so as not
to streak it but make a good smooth job of it. Put on three coats and
let each coat dry thoroughly before you apply the next one. And now
your submarine is done, and if you have made a good job of it, it will
look like the half-tone cut shown here.

=How to Work Your Submarine.=—Having everything in readiness, take your
terrible little U-boat under your arm to the nearest lake or river.

Pump the conning tower full of compressed air and then gently put her
in the water. Throw on the switch, and it will do the rest. By this, I
mean that the moment you turn on the current the motor will drive the
propeller at a goodly clip and the craft will travel over the surface
of the water awash—that is, with the water washing over her deck.

At the same time, the ballast tank begins to fill with water, and
the added weight makes the boat go deeper and deeper until only the
bridge[15] of her conning tower can be seen; and after a few moments
more her _periscope_ (or air supply tube) sinks out of sight.

While she is going down the weighted pusher is moving slowly but surely
over the threaded spindle; when it reaches the piston it pushes it
against the pin in the air-valve and so opens it and keeps it open.

The instant the air-valve opens, the compressed air from the air tank
(conning tower) rushes into the ballast tank, and because it is under
a high pressure it forces the water out of the tank through the hole
whence it came in.

When the water has been blown out of the ballast tank the boat is, of
course, lighter, and naturally she rises to the surface again. This is
your cue to be right there with a rowboat and get her and to pump more
air into the compressed air tank before she makes another trip.

If you don’t do this and she ever goes down with her ballast tank full
of water and there is no compressed air left to blow it out with, you
can send a censored report to the daily papers that another U-boat has
been sunk and that there was no time to save the crew.

But, anyway, you will have oceans of fun with your model, and your head
will brim over with submarine lore.



The Construction and Operation of a Real Submarine Simply Explained



AS we told you in the first chapter, there are two kinds of undersea
boats. These are (1) the Holland, or _submarine_ type, and (2) the
Lake, or _submersible_ type. Now, the Holland boat has a shape very
much like a cat-fish—that is, it has a blunt round head—and hence it
can dive easily; while the Lake is shaped more like an ordinary boat
and has a large _superstructure_, as that part above the _hull_[16] is
called, and this makes it easier for the Lake to _submerge_—that is,
sink on an even keel.

As the art of undersea boat building moved on apace, the two kinds of
craft began to lose their original distinctive features and were merged
into a single type. This was done to get a boat that was as strong and
as speedy as and could dive like the Holland, and to have at the same
time a boat that was as fast and as seaworthy on the surface as the

This is the reason that most of the undersea craft of to-day are a
cross between the two kinds. In the older boats, though, the difference
is still marked; but the machinery of both is just about the same,
and consequently what we shall tell you of one is just as true of the
other, and from now on we shall call both kinds simply _submarines_.

=The Parts of a Submarine.=—To begin with, a submarine is formed
of: (1) the _hull_; (2) the _superstructure_, which is built on the
hull; (3) the _steering apparatus_, which includes the submerging and
diving devices; (4) the _power plant_, which consists of the engines,
the dynamo-motors, and the storage batteries, all of which drive the
submarine when it is on the surface and under the water-line.

As the power plant is a most important part of the anatomy of a
submarine, it will need a whole chapter to describe it the right way,
and this will come next. Now I’ll start in and tell you about the other
parts of the submarine.

=How the Hull Is Made.=—The hull is made of thin but very strong sheets
of steel riveted together. As the pressure of the water on it amounts
to 187 pounds to the square inch, at a depth of 300 feet, it must be
well braced or else there would be the unpleasant possibility that it
might be crushed in. As a rule, though, a submarine never travels at a
depth much greater than 100 feet.

Now, there are really two classes of submarines: (a) those that are
built for coast patrol cruising, and (b) those that are built for
trans-oceanic going.

A submarine of the first kind seldom has rough weather to contend with,
and so she need not be built as strong as one that is designed for
ocean going. She also has a slightly different shape from the latter,
in that she has a round cross-section, as shown in Fig. 23.


By looking at Fig. 24 you will see that the ocean-going submarine
is more nearly half-round; this tends to prevent her from rolling
unduly. She also has a double hull which is divided into watertight
compartments to protect her from sinking should an enemy ship ram or
fire on her. The compartments are used as stowage tanks for fuel, etc.,
and so the space between the inner and outer _skins_, as the hulls are
called, is not wasted.

A large number of fittings are fixed to the hull, such as the _diving_
and _steering_ rudders (all of which will be described later), while
the superstructure is built on top of it.

=What the Superstructure Is.=—The _superstructure_ consists of (1) the
deck and (2) the conning tower. In the Holland submarine the deck is
only about one-third as long as the boat and this allows it to dive


The Lake boat is decked over nearly the whole length of the hull. In it
are fitted rapid-fire guns which disappear, and there are watertight
ventilators which let in fresh air when the boat is traveling on the
surface. Further there is a _hatch_—that is, an opening in the deck
with a watertight door—through which the torpedoes can be lowered into
the _hold_ of the submarine.

=The Outside of the Conning Tower.=—From out of the center of the deck
rises the _conning tower_. This is a heavily armored, shell-proof,
circular structure, from which the captain makes his observations
and sends his orders down into the engine-room and controlling
compartments. On the bridge or upper deck of the conning tower is a
hatch by which the crew can get into and out of the boat.

A steering wheel and compass are fixed to the outside of the conning
tower, and the submarine can be steered by these when it is running on
the surface. A stanchion for carrying the signal lights is also secured
to the conning tower; while the _periscope_, or eye of the submarine,
passes through the bridge and to one side of the hatch. Of this
wonderful instrument we shall have much to say a little further on.

Wires, or _stays_, as they are called, fore and aft are used to brace
and hold the periscope and signal stanchion firm against the force of
the water which presses on them when the craft is submerged and under
way. The tops of the signal stanchion and the periscope are also braced
by a _signal halyard_, which is simply a wire, or cable, stretched taut
between them.

On all modern submarines a _wireless aerial_ is attached to a mast
which can be folded down flat on the deck when the submarine is getting
ready to make a dive.

=A Look Inside of the Hull.=—Now let’s take a look inside of the
submarine. The whole hull is divided up into a number of watertight
compartments, any one of which can be shut off from the others and so
lessen the danger of sinking by ramming or by shell-fire, should the
boat be afloat. In these compartments are placed all the machinery and
the controls for operating the submarine.

These various compartments are: (1) the conning tower; (2) the
navigating compartment; (3) the engine and dynamo room; (4) the fore
and aft storage battery rooms; (5) the fuel tanks; (6) the diving
control compartment; (7) the fore and aft ballast tanks; (8) the water
pumps; (9) the fore and aft high pressure air flasks; (10) the high
pressure air compressor; (11) the torpedo compartment; (12) the mine
compartment; (13) the trimming tanks; (14) the quarters of the crew;
and (15) the quarters of the officers. All of these are clearly shown
in Fig. 25.

The watertight doors of these compartments are worked by _worm_ gears,
driven by electric motors, as shown in Fig. 25, and any of the doors
can be opened or shut by merely throwing a switch.

=A Peep into the Conning Tower.=—The free space inside of the conning
tower is not more than 8 feet in height and 10 feet in diameter.

Sticking down through the deck for about 2½ feet is the periscope, or
two of them, for all submarines now built are fitted with a pair of
them so that should one of them be hit and put out of business the
other will be available.


This instrument is formed of a long tube with a hood at the upper end,
which is outside of the conning tower, and an elbow at the lower end,
inside of the tower. An eye-piece is fixed to the lower end, so that
the captain can scan the horizon at all times. How a periscope is made
and used will be described in a later chapter.

Just below the eye-piece of the periscope is the underwater steering
wheel, and close to and to one side of the latter is the underwater
compass. In the more recent submarines a _gyroscopic compass_[17] is
used as well as the regular magnetic compass because the gyroscopic
compass is not affected by stray magnetic lines of force. Besides, a
_gyro_ compass, as it is called for short, points to the true north
instead of to the magnetic north pole, and a true compass is of the
greatest importance in guiding the submarine at night or when it is
submerged, for it is then as blind as the fish in Mammoth Cave.

Around the inside of the tower near the bridge are placed _ports_
through which the captain makes and takes his observation when the boat
is afloat. Within easy reach of his mouth are _speaking tubes_ which
lead to the engine, diving, and torpedo compartments. The captain also
has at his finger-ends an electric signal system of lights and bells,
which he operates by push buttons and switches.

So you see he can get into instant touch with all the vital parts of
his boat. He also has full control over the trimming tanks and the
storage batteries, both of which I shall tell you about in detail

[Illustration: _Courtesy of Scientific American_


Right in the line of sight of his eyes is a _depth meter_ by which he
can see at a glance at just what depth his craft is moving, and he can
also see at what _angle_[18] the diving rudder, or _elevator_, as it is
called, is set.

A compartment _tell-tale_ (a numbered chart showing each compartment
of the boat) also hangs in sight, and if a compartment should begin to
leak it is instantly indicated by the tell-tale, which in this case is
a miniature electric lamp that lights up back of the number.

By pressing a button he can ring an electric bell in the leaking
compartment and so warn the crew that he is about to close the
electrically operated _bulkhead_ door and so shut the compartment off
from the rest of the boat if the damage done is so serious that it
cannot be repaired.

=Now the Navigating Compartment.=—As you have read before, the conning
tower is not a part of the hull but of the superstructure. Now, when
the captain or any of his crew wants to get from the conning tower into
the hull of the boat he must do so through a hatch in the lower deck
which is exactly like the hatch in the top or bridge of the tower.

This arrangement makes it easy to shut off the conning tower into the
rest of the boat if it should be seriously damaged by shell-fire or
by collision. Should this happen, the boat is steered from another
compartment called the _navigating room_, in which are all of the
devices used in the conning tower. So you see there are two complete
navigating rooms and an outside deck control by which the submarine can
be steered and operated, no matter how badly damaged she may be.

=Next, the Diving Control Compartment.=—The compartment containing the
_diving control_, by means of which the submarine can be made to dive
and to come to the surface, is fitted with the following devices:

First, there is the _diving wheel_, which works the horizontal or
diving rudders.

Next, there is the _angle indicator_, which is simply a _quadrant_—that
is, a quarter of a circle—marked off into degrees and each degree into
quarters. It has a needle which moves over the quadrant as the pilot
turns the diving wheel and this indicates the number of degrees up or
down the horizontal rudders have moved.

Another instrument is the _depth indicator_.

Then there is also an indicator which is merely a modified form of a
carpenter’s _spirit_ level. This little device shows when the craft is
running on an even keel and when it is running with its keel inclined.
For instance, should the diving rudder fail to respond to the touch of
the man at the wheel, the level would indicate it, as would also the
depth indicator.

Other fittings are the levers and the valve controls, by means of which
water can be let into the ballast tanks.

Now, before I explain how the submarine is made to dive and how the
ballast tanks work, or, rather, the other way about, I want to tell
you a little about the why and the wherefore of these very interesting

=The Four States of the Submarine.=—A submarine has four states, or
conditions, in which it exists in the water. These are (1) the _light_,
or surface cruising condition; (2) the _awash_, or partly submerged
condition; (3) the _submerged_ condition; and (4) the _totally
submerged_ condition—all of which is clearly shown in the diagram Fig.


_The Light Condition._—The light, or cruising, condition is simply the
position a submarine takes when she floats on the water, due to her own
natural buoyancy, and it is exactly like that of any other ship.

While in this position the captain takes his observations from the
deck, if there is no danger of being hit by the enemy; but if there
is danger, he then makes his observations through the ports from the
inside of the conning tower.

_The Awash Condition._—This condition is not as natural as the one
just described, and it has to be done by means of the ballast tanks.
These are located fore and aft and they can be connected with, or
disconnected from, each other at will.

Now, when the captain wants to bring his submarine to the awash
condition an _inlet valve_, or _Kingston valve_ as it is called, is
opened and the sea-water then flows into these tanks, the amount and
velocity of the inrushing water being, of course, under control at all

This extra weight destroys part of the buoyancy of the boat, and as
she gets heavier she sinks until nothing but her conning tower remains
above the water-line, the deck being awash. While in this condition
observations are taken either from the ports in the conning tower or
with the periscope, the object-glass of which has been lowered enough
to become useful.

_The Submerged Condition._—In this condition the periscope alone
remains above the water. It is had by allowing more water to flow
into the ballast tanks, thus destroying a little more of the craft’s
buoyancy, which makes her sink down until the conning tower is
completely submerged. It is in this condition that the captain makes
his observations with the periscope.

_The Totally Submerged Condition._—This is an exaggeration of the
submerged condition, and it is had by letting still more water flow
into the ballast tanks, thus sinking the submarine completely. The only
way to steer the boat when it is in this condition is, of course, by
means of the compass, for both the conning tower and the periscope are
totally submerged.

But do not mistake the term _totally submerged_ to mean that the
buoyancy of the submarine is _totally destroyed_; for such is not the
case during any stage of its submergence. You can easily see that if
the buoyancy were completely destroyed the submarine would then become
a dead weight and sink to the bottom of the sea, never more to rise.

Instead, when the submarine is totally submerged she can, by what
is known as her _reserve_, or _extra_ buoyancy, and about which you
will read later on, come to the awash or the light condition in a few
minutes by simply pumping the water out of the ballast tanks.

=How a Submarine Dives.=—Now let’s get back to the way a submarine
dives. In the first place, let us suppose the boat is running in
the light, or cruising, condition. An enemy ship is sighted and the
captain of the undersea craft gives orders to clear the deck and close
the hatches. Then he brings the boat from the cruising to the awash
condition, which is done as we have just described.

Next, he gives the order to the man at the diving wheel to make the
dive. He does not need to do this by word of mouth but he can use an
electric indicator which points out the angle at which he wants the
horizontal rudders set (see Fig. 27). Contrary, now, to what you might
expect, a submarine cannot dive at any angle, but it must make a very
shallow dive.


[Illustration: FIG. 28. HOW THE SUBMARINE DIVES.]

So when the order is given, the diving rudders are set at only ½ a
degree from the horizontal, as shown in Fig. 28. The craft must move
through the water at about 5 knots, which is the proper diving speed.
When the conning tower is one-fourth submerged the angle of the rudders
is increased to 1¼ degrees.

This angle is held until the conning tower is half submerged; and then
the angle is changed to 2 degrees, and it is held there until the
conning tower is three-quarters submerged. As soon as this takes place,
the angle is decreased to 1¼ degrees again, and the rudders remain at
this angle until the dive is completed.

_Why a Shallow Dive Is Made._—The reason such a shallow dive must be
made is the result of having to let water into the ballast tanks to
bring the craft to the awash condition before diving.

If the angle of the dive were to be suddenly increased to 10 or 15
degrees the tilting of the boat would throw all the water forward in
the tanks and this would seriously upset her balance, and might even
make her settle nose downward to the bottom of the sea.

_How the Boat Is Kept Submerged._—When a dive is to be made the diving
rudders are set at the angles just mentioned, but water is not let into
the ballast tanks at the same time, for this would also tend to destroy
the balance of the boat.

But when the captain wants to keep his submarine at a certain depth
below the surface of the water after the dive is made he has water
admitted to the ballast tanks and this keeps her at that level. When he
wants to return to the surface, or “break water,” the water is pumped
out and then the diving rudders are set and the boat makes an upward

_The Time It Takes for a Dive._—The time needed for a submarine to
get ready to dive is about 2 minutes; but this is often long enough
for it to become a target if a submarine chaser is on the little
war-dog’s trail. Should she be hard pressed she might dive at a steeper
angle—say, 5 degrees, but never more, and under ordinary conditions she
will never dive at more than 2 degrees’ inclination.

The reason it takes time for a submarine to get ready to dive is
because the wireless masts have to be folded in, the machine guns
disappeared, and the hatches fastened down. Finally, it must not be
forgotten that a submarine can dive only when she is pushing ahead
under power. If she is at rest and the captain wants her to sink he
must either start her engines or else be content to simply submerge her
on an even keel.

=The Ballast Pumps and What They Do.=—The pumps which pump the water
from the ballast tanks are driven by electric motors. They must be
powerful pumps, for they not only have to pump the water out of the
tanks quickly, but they have to force it out against the pressure of
water in which the submarine is submerged; this pressure increases the
deeper the boat sinks, and it is often 80 pounds or more to the square
inch. The pumps are controlled from the conning tower, and also from
the navigating compartment.

=What the Buoyancy Tanks Are For.=—We said previously that a submarine
never loses its buoyancy completely. If she were built like an
ordinary ship and simply fitted with ballast tanks, she would sink when
these are filled with water and never come up again, for her natural
buoyancy would be destroyed. As it is, a submarine has tanks filled
with air which keeps her buoyant, and these will bring her to the
surface the moment the ballast tanks are empty.

Make this experiment and you will quickly understand how these buoyancy
air tanks work: Take an empty bottle and cork it up tight. It looks
empty, but as a matter of fact it is filled with _air_. Push the bottle
to the bottom of a bucket of water; let go of it and the instant you do
so it will rise to the surface.

A large number of steel air tanks, or buoyancy tanks, or high pressure
_air-flasks_, as they are called, are placed both fore and aft in a
submarine, and these are filled with compressed air at a pressure of
2,000 pounds to the square inch. These air-flasks have a tremendous
supporting power—which is only another way of saying that they are
extremely buoyant.

It must be clear now that even though the submarine is resting on the
floor of the ocean it can always rise to the surface by the _reserve
buoyancy_ provided by these air-flasks.

=Compressed Air and Air-Compressor Pumps.=—The air-flasks are filled
with compressed air by _air-compressor pumps_ which are driven by the
engines when the submarine is running light or awash.

The air compressor is formed of several air pumps coupled together;
each air pump is made very much like a water pump, but it sucks the
air in from the outside and then forces it into the air-flasks until
it is under a pressure of 2,000 pounds to the square inch. To overcome
this _back pressure_, as it is called, the pumps must be extra powerful.

These pumps also supply compressed air for the torpedo tubes, the
trimming tanks, and to help blow out the water from the ballast tanks.

=Inside the Torpedo Compartment.=—The torpedo compartment contains
the extra torpedoes in their cradles. Near the tubes from which the
torpedoes are shot is the compressed air which furnishes the propulsive
power needed to make the torpedoes leave their tubes.

=Why Trimming Tanks Are Used.=—As a torpedo weighs nearly 1,000 pounds,
it is plain that whenever one is shot from the craft it will very
greatly disturb the balance of the boat unless some means is used to
add weight to it which is exactly equal to the weight of the torpedo.

This is done by what is called the _trimming tanks_. These are usually
placed fore and aft and in or near the torpedo and mine compartments.
As soon as a torpedo is shot, or a mine is laid, the trimming tanks
are filled with water which makes up for the weight lost and keeps the
craft on an even keel.

If, on the other hand, any extra weight is taken aboard the submarine,
enough water to equal it is blown out by compressed air.

=In the Mine Compartment.=—The mine, as the stationary bombs that are
to be laid in a harbor or some other _strategic_ point are called, are
kept in the mine compartment.

This compartment has a trap door in it through which a _mine-layer_,
that is a man dressed in a diving-suit, can get out of and back into
the submarine again, or through which the mines can be lowered.

[Illustration: FIG. 29. MUSHROOM ANCHOR.]

=And Last of All, the Sea Anchor.=—A submarine must have an anchor as
well as a merchantman. The anchor is of the _mushroom_ type, so called
from its appearance; and as you will see from the accompanying picture
(Fig. 29), it is very different from the two armed and fluked kind that
so resembles an Irishman’s anchor i.e., a pickax.

=Where the Crew of a Submarine Lives.=—Proper quarters for the officers
and crew in the earlier submarines were sadly neglected; but conditions
have greatly changed since then—though of course they are not quite so
good as living in a luxurious hotel ashore.

Great improvements have been made in behalf of the undersea navigators
and sailors, until in the more recent submarines the crew have quarters
that compare favorably with those on board a battleship.

There are oxygen tanks that supply pure air, while electric fans set up
a forced draft and keep the air cool and make it circulate freely. Then
there are electric heaters which keep the temperature just right under
all conditions.

It goes without saying that the modern submarine has its _galley_—that
is, its cook room. But, very different from the galley on the old
windjammers that used to sail the seas, the sea-cook does not use a
cook-stove, which was also called a galley, but electricity.



How the Submarine is Driven on the Surface and Undersea. An Explanation
of the Operation of the Gasolene Engine, Storage Battery, Motor and



SINCE the time of the first propelled underwater boat great strides
have been made in the methods of driving the submarine, until at the
present day the _power plant_ seems to be well-nigh perfect.

As the steam engine was improved upon, its value for driving submarines
became better thought of by inventors, not because it was at all
suitable for the purpose, but in virtue of the fact that it was the
first and for a long time the only practical scheme to produce power
on a large scale. For this reason, all the early and even some of the
later submarines were powered with steam engines.

=What a Good Power Plant Is.=—There are certain things an engine must
be and do to make it useful for driving a submarine boat, and among the
chief ones are:

(1) It must be as small and as light as possible and still have great

(2) It must develop a lot of power for its size and weight.

(3) It must use a small amount of fuel for the power it develops.

(4) The fuel it uses must not be bulky for the power it gives.

(5) It must not give off odors.

(6) All working parts must be easily getatable, and

(7) It must not give off poisonous gases, or vapors that ignite easily,
for either of these are dangerous.

From this you will see that it is not an easy matter to make an
engine for a submarine that will have all of these good features, but
inventors have come pretty close to it, as you will presently learn.

=The Faults of the Steam Engine.=—Now while the steam engine was the
only motive power that could be used in the early submarine for driving
it when both afloat and under water, it lacked nearly every one of the
good features named above; for,

(1) While a steam engine can be made light and strong, a large heavy
boiler is needed, and this makes the boat a very hot and unhealthful
place for the crew; (2) it is very wasteful of fuel, for most of the
heat energy[19] that is stored up in the coal or oil is lost before it
ever reaches the engine; (3) if coal is used, it is too bulky, and if
oil is used it is too liable to give off vapors which will catch on
fire and explode.

These untoward features did not matter so much when the submarine was
afloat, but when she was cruising below the water they were all present
to make life miserable for the crew. But when the _storage battery_
was put into such shape that it could be used, all this was changed and
the conditions were so improved that undersea travel became bearable
and pretty safe as well. We will tell you all about the storage battery
and how it develops power a little further on.

=When the Gasoline Engine Came.=—The next improvement in submarine
power plants came when the gasoline engine was made practical.

This new kind of a _prime mover_[20] was so much better in every way
than the steam engine that nearly all submarines now built are powered
with them in one form or another.

The usual kind of gasoline engine is known as the _four cycle type_
and has from 12 to 16 _cylinders_, the _pistons_ of each of which are
connected to one _crankshaft_, and together they form a _power unit_,
as the complete engine is sometimes called.

A submarine engine of this kind can develop upwards of 5,000 horsepower
and the large units weigh close to 100 tons. Except that it is larger
and is built especially to meet the needs of the submarine it is
exactly like a motor car or an airplane engine which is shown in Fig.

=How the Gasoline Engine Works.=—A single cylinder gasoline engine is
easier to understand than one with four or more cylinders, so I’ll
describe it first.



It consists of (1) a _cylinder_ with _valves_ in it and in which a
piston moves to and fro; this is connected to (2) a crankshaft by means
of (3) a piston rod as shown in Fig. 31. To the cylinder is fixed (4)
a _carburetor_ which mixes the gasoline with the air and forms the
explosive gas, or _fuel mixture_ as it is called, and (5) a _high
tension magneto_ which generates an electric current to make the spark
that fires the fuel mixture, etc.

It is easy to understand how a gas-engine works if you will just
remember that for every _power stroke_ there are three other strokes,
making four strokes altogether, or _four cycles_ as it is called.

The power stroke of the piston is the stroke made by the explosion of
the fuel mixture and this forces the piston down. This is the stroke
that turns the crankshaft _one-half_ of a revolution and gives it force
enough to carry it around until the next power stroke takes place. Thus
the flywheel of a single cylinder four-cycle engine makes two complete
turns or revolutions to each power stroke of the piston.

Fig. 31 shows how the inlet and exhaust valves are worked, each one
by a little wheel with a lump on one side, or _cam_, as it is called,
which is fixed on a _cam-shaft_ and is turned by the crankshaft. The
cams, of which there are two for each cylinder, are set directly under
the ends of the _valve rods_, and as the cam-shaft revolves, the little
lumps on the cam strike the valve rods at the right moments and this
lets the fuel mixture into the cylinder and lets the used and burnt-up
gases out of it.

Each valve is provided with a stiff spring, which, as soon as the lump
on the cam has turned past the valve rod, lets the latter drop again
and so closes the valve.

Fig. 31 also shows the complete action of a four-cycle engine. The
_suction stroke_ is shown at _A_; as the piston moves down, the cam
forces the inlet valve up and the piston sucks the fuel mixture into
the cylinder. The exhaust valve is closed while this stroke is taking

The _compression stroke_ is shown at _B_; the _momentum_, that is the
stored up energy of the flywheel, carries the piston up and forces the
fuel mixture into a very small space, that is, it _compresses_ it. By
this time the cams have moved past the valve rods and both the inlet
and exhaust valves are closed.

The _power stroke_ is shown at _C_, and this is the only one of the
four strokes that actually counts. When the fuel mixture is compressed
it is exploded by an electric spark and the force of the explosion
drives the piston down and gives the flywheel great momentum.

It is the momentum produced by this stroke that not only furnishes
enough power to carry the flywheel round until another power stroke
takes place, but also furnishes the excess power to do useful work,
such as to drive a dynamo or a propeller. Of course both valves are
closed when this stroke is being made.

The _exhaust stroke_ is shown at _D_ and is one of the up strokes of
the piston. The cam opens the exhaust valve and the piston forces the
burnt gases of the fuel mixture out of the _exhaust port_, and that
clears the cylinder for the next stroke, which will be the _A_ stroke
over again, and so on through the same four cycles just described.

_The Carburetor and What It Does._—This apparatus is connected to the
_fuel tanks_, which usually contains gasoline, by a supply pipe. The
gasoline is forced out of the tank by compressed air being pumped into
the latter and thence it passes into the carburetor.

The carburetor changes the liquid fuel into a fine spray, or vapor, and
mixes it with air, and this is drawn into the cylinder when the inlet
valve opens and the piston is making its suction stroke.

_The Magneto Electric Machine._—This is an electrical device which is
simply a little dynamo. When it is driven by the engine it generates a
_high tension current_ of electricity which will jump between the ends
of two wires ⅛ inch apart, and this makes a spark.

The magneto is connected to a _spark-plug_ which is screwed into the
head of the cylinder. A _timer_ connected to the magneto and the
spark-plug closes the circuit each time the compression stroke is
completed; the instant the circuit is closed the current generated by
the magneto makes a spark at the business end of the spark-plug and
this fires the fuel mixture.

But as good as the gasoline engine is for motor cars, power boats,
and airplanes, it has been found sadly wanting as a power plant for
submarines; this is due not to any fault of the engine but to the
explosive nature of the gasoline which is used.

Gasoline is a very _volatile_ liquid, that is, at ordinary temperatures
and pressures it tends to change from its liquid state to a vapor which
is really a gaseous state. You may have noticed this if you have been
near a place where gasoline is stored, for the whole air is _saturated_
with the vapor given off by it and this is what you smell.

Further, it is quite impossible to store a fuel like gasoline, and to
use it for firing an engine in such a confined space as there is on a
submarine, without the air becoming charged with the vapor, which is
injurious to those who breathe it, and which, should it be accidentally
ignited, would explode with such force that it would wreck and sink the

=The Last Word in Submarine Engines.=—Having tried out both steam and
gasoline engines for submarine work and both having been found wanting,
further experiments were made in engine building.

Now, since it was known that the chief fault of the gasoline engine
lay in the fuel it used and not in the engine itself, inventors worked
hard to make an engine that would burn a fuel so much heavier and less
volatile than gasoline that all danger from vapor would be done away

Many engines were built along this line, but all failed until Diesel
(pronounced Dé-sel), a German inventor, found a way to make an engine
that would burn a heavy oil. The Diesel engine is now used in every
submarine that is built, nearly; and for this reason I want you to
understand exactly how it is made and how it works.

_How the Diesel Engine Works._—The Diesel engine works on the same
general principle as the gasoline engine—that is, by the explosion of
a fuel mixture in the cylinders—but it is different from the gasoline
engine in the way in which the fuel is admitted into the cylinder and

In the Diesel engine, a rough diagram of which is shown in Fig. 32,
there are two valves in the head of the cylinder, one of which lets in
the heavy fuel mixture and the other one admits compressed air to the
cylinder. The exhaust valve is at the bottom of the cylinder, and the
lower part of the cylinder is built to form an air compressor.

[Illustration: FIG. 32. A TWO-CYCLE DIESEL ENGINE.]

The way it works is like this:

(a) When the compressed air valve opens, the compressed air is forced
into the cylinder and this drives the piston down when the valve closes.

(b) The power that this stroke gives to the flywheel forces the piston
up again, and this compresses the air as shown in _A_, Fig. 32. Now
when you compress air, it heats it, and the amount of heat developed
depends on how much the air is compressed; you can even feel the heat
that is set up by compressing the air in a toy pop-gun; or you may have
noticed that when an automobile tire is pumped up fast it gets hot. Of
course, while the air is being compressed in the cylinder of the engine
the compressed air valve stays closed.

(c) When the fuel inlet valve opens, the heavy fuel is forced into the
cylinder by means of compressed air which presses on the fuel in the
supply tank. The instant the fuel strikes the hot air in the cylinder
it ignites and burns, and as it burns it expands just as the gases of
burning powder in a cartridge expand. This forces the piston down and
makes the power stroke as shown in _B_, Fig. 32.

Here, then, is another great advantage of the Diesel engine over the
ordinary gasoline engine: it does not need an electric spark or any
other kind of flame to fire it.

(d) As soon as the piston has reached the down end of its power stroke,
the exhaust ports are opened and more compressed air flows through the
compressed air valve; this blows what is left of the burnt gases out
of the cylinder through the ports, and as soon as this is done the
piston starts to go up, when it compresses whatever air there is in the
cylinder again.

While this stroke is being made the air compressor piston in the
bottom of the cylinder, which is a part of the regular piston, has
been compressing the air needed to perform the above operations. Since
there is only one waste stroke to every power stroke, the engine is
a _two-cycle_ one, and herein lies its third big advantage over the
gasoline engine.

[Illustration: _Courtesy of Scientific American_


The reason that the Diesel engine is better adapted to burn heavier
oils than the gasoline engine is because the latter uses an electric
spark to ignite the fuel mixture and this must be very light and
volatile, since the spark is not hot enough to fire the heavier oils.

Again, in a gasoline engine the fuel mixture _explodes_—that is, it
burns very rapidly, like the powder charge in a cartridge—whereas in a
Diesel engine the fuel mixture _expands_ when it is ignited, very much
as steam expands in the cylinder of a steam engine.

Using heavy oils very greatly reduces the cost of operating an engine,
for oils of this kind are usually the _by-products_ obtained in the
making of petroleum and gasoline. These heavy oils are of little value
for any other purpose than fuel; and, also, since the oil is heavy, it
is more easily handled than gasoline.

For these very good reasons the Diesel engine (Fig. 33), is used by
nearly every government at the present time for submarine power plants.
Moreover, like the steam engine, it will develop its greatest power,
nearly, on starting; it does not need any _reducing gears_ to lower its
speed—this is done with a _throttle_ as it is in a steam engine; and
it can be reversed without a reversing gear, which is better than the
steam engine.

The Diesel engines of present-day make range from 900 to 5,000
horsepower, and eight or more cylinders are used for each engine. The
weight of the engine is about 30 pounds per horsepower; or for a 5,000
horsepower engine the weight is in the neighborhood of 70 tons. As
great as this weight may seem, it is much lighter for the horsepower
produced than the old-fashioned gasoline engine.


=Why An Electric Power Plant Is Needed.=—As you know, a submarine has
two chief conditions, and these are (1) when it is _afloat_, and (2)
when it is _submerged_.

When she is afloat the air in the craft and which the crew must breathe
is being constantly sucked in from the outside, and there is always a
large enough supply to keep the compartments clear and to furnish the
air compressors which fill the tanks. But when the boat is submerged
there is no way of getting a fresh supply unless air is taken from the
tanks or the submarine goes to the surface every little while, like a
whale, and this would hardly do.

=The Dynamo-Motor and Storage Battery System.=—When the storage battery
came into use inventors of submarines were quick to see that the thing
to do was to use two separate and distinct power plants and these are
(1) the steam or gas engine, which is used when the boat is running
afloat; and (2) the electric storage battery system, which is used when
the craft is running submerged.

Three devices must be used for the undersea electric power plant,
namely, (1) the _dynamo_, which generates the electric current; (2) the
_storage battery_, which is charged by the current generated by the
dynamo, and (3) the _motor_, which develops power when a current from
the storage battery is made to flow through it. The diagram shown in
Fig. 34 will make the electric connections clear.

_About the Dynamo._—The _dynamo_[21] (see Fig. 34) is connected to the
crankshaft of the engine and is driven by it. It changes the mechanical
motion of the engine into an electric current. This electrical energy
must then be stored up so that it can be used later when the craft is
submerged and it is wanted.

[Illustration: FIG. 34. A SUBMARINE DYNAMO MOTOR.]

_And Now the Storage Battery._—To store up the electrical energy a
_storage battery_ (see Fig. 35) is used. When the current is made
to flow into this kind of a battery it charges the battery, and if
then the battery is connected to a motor it will deliver an electric
current, and this runs the motor.

The storage battery has been almost as big a bugbear to the submarine
builders as the oil engine. It must be as small and as light as
possible; it must not absorb the oxygen of the air which the crew
breathes, and it must not give off any poisonous gases.

Now, there are two kinds of storage batteries, and these are (1) the
_lead-plate_ storage battery, which is the oldest form, and (2) the
_nickel-steel_ storage battery, which was invented quite recently by
our own Edison. Both kinds are used in submarines.

[Illustration: FIG. 35. A SIMPLE STORAGE BATTERY.]

_Last of All, the Motor._—The motor is the last device by means of
which the electric energy is made to drive the craft when it is

Now, a dynamo and a motor are made exactly alike, in fact, a dynamo
is a motor and a motor is a dynamo. That is to say, if you turn the
_armature_ of a dynamo, it will generate a current of electricity, and
if you make a current flow through the coils of a dynamo, the armature
will spin round and it is then a motor.

This being true, however strange it may seem, only one electric machine
is needed to do the work of the dynamo and the motor; for when it is
connected to the shaft of the engine it will generate a current for
charging the storage battery, and this is done while the craft is
afloat; or it will develop power to drive the propellers when it is
connected to the storage battery, and this is done when the submarine
is cruising undersea.



Full Instructions and Working Drawings for Making a Model Torpedo. How
a Real Torpedo is Made, Directed, Shot and Explodes



THE submarine is first, last, and all the time an engine of death and
destruction. Even in the earliest underwater experiments, you will
remember, it was fitted with a bomb the sole purpose of which was to
blow the enemy ship to atoms.

The old bomb idea proved next to worthless, for it was a very hard job
to fix it to the ship to be sunk, and even if the submarine operator
did succeed in so doing it was at best a dangerous piece of business,
and so the odds for its failure were about as 100 is to 1.

As soon, therefore, as the submarine had been developed to a point
where it was clear that it was the coming weapon of modern naval
warfare, inventors began to rack their brains for some scheme which
would do away with the danger and uncertainty of the old-fashioned
bomb, and to make the submarine safer for its crew and deadlier for the

Many attempts were made, but its improvement was very slow, for the old
idea of the simple bomb was firmly fixed in the minds of the inventors
and it was hard for them to break away from it.

After a long time, though—that is to say in 1860—Captain Lupius, an
Austrian inventor, hit upon a new and novel plan for a torpedo which
would travel under water, by means of a little motor in it and a pair
of wires which connected it with the submarine so that it could be
directed at will.

=The First Submarine Torpedoes.=—Lupius took his idea to Whitehead,
an English engineer of genius and ability, and he built the first
controlled torpedo which traveled under its own power in 1864. Then
Whitehead did a little thinking on his own account and he built the
_automobile torpedo_ in 1868, the cleverest and most diabolical
destroyer that man has ever yet been guilty of.

The automobile torpedo is one that not only runs under its own power
but that steers itself as well after it has left the torpedo tube of
the submarine. To Whitehead, then, must be given the credit not only of
having invented the submarine torpedo that is used with such telling
effect in the present war, but of making a success of it. The Germans,
though, with their great dislike for everything of British name and
make call their torpedo of this type _blackheads_.

=How to Make a Model Submarine Torpedo.=—Before I explain how a real
automobile torpedo is made and works, I will tell you how to make a
model torpedo which, while it will not explode at the end of its trip
through the water, will show you how a real torpedo does its work.

=The Body of the Torpedo.=—Get a piece of nice soft pine 1½ inches in
diameter and 10 inches long, and whittle it out to the shape shown
in Fig. 36. Cut a groove down the middle of it ¾ inch deep and ¾ inch
wide, to within an inch of each end. This done, screw a small screw-eye
in the _warhead_ of the torpedo, as the blunt nosed end of it is
called, inside the groove.

[Illustration: FIG. 36. A MODEL TORPEDO.]

Bore a ⅛-inch hole through the propeller end, and slip a piece of brass
tube 2 inches long which has a bore of inch in it to form a bearing
for the propeller shaft. Get a brass rod 1/16 inch in diameter and 2¼
inches long; make an eye on one end and then push the rod through the
brass tube in the tail or propeller end of the torpedo, as shown in
Fig. 36, and this is all there is to the propeller shaft. Now cut a
propeller out of tin, as shown at _E_, in Fig. 37, and solder it to the
end of the propeller shaft.

_The Steering and Diving Rudders._—The torpedo, like the submarine
itself, has two rudders, one for diving and one for steering.


To make the _steering rudder_, which is the vertical one, cut out a
piece of heavy tin 1½ inches wide and 1¾ inches long, as shown at _A_
in Fig. 37; cut out one edge ⅜ inch deep as shown by the shaded part,
which will leave a tongue sticking out from each corner, and bend these
to form little tubes.

Cut off two pieces of wire ⅛ inch thick, have each one 2½ inches long,
and bend them as shown at _C_. Next drill two holes through the tail or
propeller end of the torpedo, force the sharp ends of the wires into
them and then put the other ends into the tubes of the rudder.

The _diving rudder_, which is the horizontal one, is made like the
steering rudder except that the tongues for the hinge tubes are dropped
down a little and a slot ½ inch wide and 1¾ inches long is cut out, as
shown by the shaded part at _B_.

This rudder is 1½ inches wide and 2⅛ inches long; it is fastened by a
pair of ⅛ inch wires to the tail end of the torpedo in the same way
as the steering rudder. This arrangement leaves enough room for the
propeller to turn inside of the wires, as shown at _C_.

_The Rubber Strand Motor._—The next thing to do is to fix one end of
the rubber strands to the screw-eye in the warhead and the other end to
the eye of the propeller-shaft. This gives you a cheap and simple motor
that is at once light, powerful, and easy to manage.

Cut out a cover of wood to fit over the groove containing the motor,
as shown in _D_, Fig. 37, and screw it to the body of the torpedo.
Melt some paraffin wax and run it around the cracks to make the motor
chamber watertight.

Bore half a dozen or more holes ½ inch in diameter and about an inch
deep along the exact middle of the bottom of the torpedo; fill each
hole with shot and seal them in with sealing-wax. There must be enough
shot in the bottom to weight the little torpedo so that it will just
sink on an even keel when you put it in the water. Finally, paint the
torpedo all over with black enamel (you can buy it in drug stores for
10 cents a can), and your model torpedo is ready for its deadly work.

=Your Torpedo in Action.=—To set your model torpedo scooting under the
water and, perchance, aimed at an enemy ship, fix the steering rudder
in a line with the long axis of the hull and tilt the diving rudder
at a very slight angle, say about 2 degrees, down from the top of the

Hold the hull with your left hand and wind up the rubber strand motor
good and tight by turning the propeller _clockwise_—that is, in the
direction the hands of a clock move—with your right hand. When you
have done this, push the torpedo down under the water, let go of the
propeller and she will shoot forward as though shot by compressed air
from a torpedo tube.

After it has made a run of from 25 to 100 feet—the distance depends on
the skill you have shown in building it—it will sink to the bottom.

Of course if you are playing a naval war game and you are shooting at
some enemy ship, it will give her a good hard bump, and this counts
ten points in your favor.

=How a Real Torpedo Is Made.=—A torpedo, as you can plainly see, is
nothing more nor less than a miniature submarine boat that moves under
its own power and that is self-controlled. And now that you have
built and experimented with a little model it will be easy for you to
understand how a real one is made and works.

_The Warhead of a Torpedo._—A real torpedo such as is shot by a
submarine to sink real ships is made of three chief parts, as far as
the outside of it is concerned. These are: (1) the _warhead_, (2) the
_body_, and (3) the _tail_.

The warhead is the blunt-nosed hollow part that forms the business end
of the torpedo; it contains two things: (a) the charge of _high powered
explosive_ which plays such terrific havoc when it is touched off; and
(b) the _detonating mechanism_ which fires it.

_The High Powered Explosive._—The explosive used is either
_guncotton_, or _nitrocellulose_, to call it by its chemical name, or
_tri-nitrotoluene_ (pronounced _ni-tro-tol´-u-en_) and which is called
_TNT_ for short.

Guncotton is simply ordinary cotton which has been treated with nitric
and sulphuric acids; when this is done it becomes highly explosive.

_TNT_ is _toluene_, a chemical formed of hydrogen and carbon, which
has been treated with nitric acid. It is used by the Germans in the
warheads of their submarine torpedoes because it is a more powerful
explosive than guncotton. Besides it can be melted as easily as lard
and poured into the warhead, which makes it an easy, quick, and safe
job to fill them. Further, it does not explode easily by shocks when it
is transported but it instantly explodes with a _detonator_.

The reason these explosives cannot be ignited by fire but explode when
struck a sharp tap is because they are very _unstable compounds_; that
is, they are very easily decomposed into their original chemical parts.

Curiously enough, but by the very discovery of this advanced scientific
principle men are now able to make the mightiest, which means the
deadliest, explosives that the world has ever known and this makes
war a thousand times as terrible now as it was in the olden days when
men fought their battles at close range with their ancient lances and

=The Detonating, or Firing Mechanism.=—A modern submarine torpedo has
a diameter of from 18 to 21 inches through the warhead, and this is
loaded with from 200 to 330 pounds of guncotton or TNT, as the case may

This _charge_ is exploded by a _firing pin_, or _pistol_, as it is
called. This firing pin goes clear through the charge and into a
_percussion cap_, which sets just back of the charge; the other and
front end of the firing pin goes clear through the warhead and has a
threaded end on which is screwed what is known as a _butterfly-nut_.

[Illustration: _Courtesy of E. W. Bliss Co._


The percussion cap is simply a little copper cup and in it is placed
a small charge of an explosive which is easily detonated by the
_percussion_ of the pin, that is by the pin striking it. The explosive
mostly used in percussion caps is _mercuric fulminate_, which is a
compound formed of mercury, carbon, nitrogen, and oxygen.

Since it is the violent explosion of the percussion charge which
strikes the main charge of the high explosive in the warhead, and the
fire made by the explosion of the percussion charge has nothing to do
with it, the main charge of guncotton, where this explosive is used,
is often wet down with water before it is packed in, for by so doing a
great deal more of it can be put in the same-sized space.

A _safety pin_ (see Fig. 38) is set into the firing pin, so that by
no possible chance can the latter pin work loose and explode the
charge until it strikes the ship it is intended to destroy. Also the
butterfly-nut, which I spoke of above, is used as a further safety

The safety pin is simply a pin which is threaded on one end and which
extends down through the steel casing of the warhead and screws into
the firing pin, or pistol, and holds it securely so that it cannot
strike back against the charge until it is unscrewed and taken out or
broken off, when it strikes the ship.

The butterfly-nut is simply a thumb nut with a couple of wings on it.
When the torpedo is shot out of the torpedo tube the butterfly-nut,
which is screwed up close to the warhead on the firing pin, begins
to unscrew itself by the action of the water on the wings, which now
form little propeller blades; by the time the nut reaches the end of
the firing pin and drops off, the torpedo is quite a distance from
the submarine which shot it. In this way, all danger of the torpedo’s
exploding when it is in, or leaving, the submarine, is done away
with. Fig. 38 shows a cross-section of the warhead and just how the
detonating mechanism is made and works.


The warheads of the latest torpedoes, especially those used by the
Germans, are fitted with steel cutters, so that they can cut their way
through nets which ships may spread out to protect themselves.

_The Body of the Torpedo._—The next part of the torpedo is the body,
and there are five separate and distinct parts to it. These we have
named in the order of their position, and they are,

(1) The _air pressure chamber_; (2) the _balance chamber_; (3) the
_power chamber_; (4) the _buoyancy chamber_, and (5) the _tail-piece_
which supports the propellers and the rudders.

_The Compressed Air Tanks._—The air pressure chamber is simply a large
steel tank and air is pumped into it until it is under a pressure of
about 2,000 pounds to the square inch; this means that for every square
inch of the surface of the tank there is a force pressing against it of
about one ton.

The air is let out of the tank through what is known as a _reducing
valve_, which is in turn connected to the engines, and more about it
will be said a little later. A reducing valve is simply a valve that
regulates the amount of air which flows from the tank into the engine
and keeps it at the same pressure all the time.

If the valve were not used, the air in the tank, which is at first
under 2,000 pounds pressure, would drive the torpedo forward at a
tremendous rate of speed at first, but as the air from the tank was
used up by the engine it would lose pressure and the torpedo would soon
stop altogether. But when a reducing valve is used the torpedo keeps up
its same high speed until it has run its course and has either hit the
ship or missed it.

_What Is in the Balance Chamber._—In the balance chamber is the
mechanism that controls the steering and the diving rudders, and it is
these that keep the torpedo on a straight course and at the right depth
under the water.

The controlling mechanism is formed of four chief devices, which are
(1) a _gyroscope_ (pronounced _ji´-ro-skop_); (2) a _compressed air
motor_, which drives the gyroscope; (3) a _water pressure control_; and
(4) a _pendulum control_.

_The Automatic Gyro Control._—The gyroscope, or just _gyro_, as it
is called for short, is a kind of spinning top and you can buy a toy
one for a quarter.[22] It is simply a heavy wheel fixed to a shaft, or
spindle, and this is pivoted in a ring, as shown at _A_ in Fig. 39.

[Illustration: FIG. 39. THE GYROSCOPE.]

Now hold the gyro as shown at _B_ and give the wheel a good spin.
This done, walk straight ahead, and as long as you do so you will
hardly know that you are carrying the gyro, but the moment you try to
change your direction you will feel the gyro twisting in your hand to
counteract the movement.

This is the purpose of the gyro in a torpedo, but in this case the
wheel is very heavy and it is revolved at a high speed by a compressed
air motor. The gyro is set with its shaft at _right angles_ with the
long axis of the torpedo, as shown at _C_.

Now, just as long as the torpedo moves straight ahead in its course,
the gyro has no effect on it, but the moment the torpedo tries to
swerve from one side to the other, or shift out of its course, the
gyro pulls it back by acting on the steering rudder; it does this
by regulating the air supply of a compressed air motor, called the
_servo-motor_, and this in turn works the rudder by means of a series
of levers. In this way the torpedo is automatically kept to its course.

_The Hydrostatic, or Water Pressure, Control._—The water pressure
control is one of the devices which keeps the torpedo at the right
depth in the water.

It consists of a steel cylinder with a piston working in it. A cylinder
which is open at both ends is set in the hull of the torpedo so that
one end opens into the water outside. A spring presses against the
piston on the inside of the hull and the water presses on the piston on
the outside.

The spring can be adjusted by a screw to just balance the pressure of
the water at any depth. A small valve rod is fixed to the piston, and
this opens a valve which lets compressed air into a motor when the
pressure of the water is greater or lesser than the pressure of the
spring and this in turn works the diving rudder as shown in Fig. 40.

Suppose, for example, that the captain wants the torpedo to travel
at a depth of exactly 15 feet during its whole course. The spring is
adjusted to offset the pressure of the water at this depth, and the
torpedo is launched. Should it for any reason try to go deeper than 15
feet or to rise above 15 feet, the spring or the water presses on the
piston and closes or opens the air valve of the motor, when it moves
the diving rudder up or down until the torpedo is brought back to its
right depth.


_The Automatic Pendulum Control._—The water pressure control, however,
is not enough to make the torpedo stick to an absolutely constant
depth, and so to help it a _pendulum control_ is also used.

This control consists of a pendulum which swings to and fro from
fore to aft as the torpedo dives and rises, and it also starts the
compressed air motor which operates the diving rudder, and this brings
the torpedo back to its proper depth. It is shown in Fig. 41.

=The Engine That Drives the Torpedo.=—Next comes the engine that drives
the torpedo, and it, too, is run by compressed air.

As I mentioned before, the air which runs it is regulated by a
reducing valve, but there is another important part of the power plant,
and this is the _heater_ for heating the compressed air before it is
admitted to the engine.

[Illustration: FIG. 41. THE PENDULUM CONTROL.]

Compressed air is as good to run an engine with as steam, for both
of them have tremendous powers of expansion. As soon as the air is
released from the supply tank—which keeps it compressed in a space that
is many times smaller than it would take up when it is free—and has
passed into the cylinders of the engine, it begins to _expand_, or to
spread out in every direction, exactly as steam does.

Now when air is pumped into the tank it gets very hot and this heat
is stored up in the air as _energy_; this makes the air when it is
released expand with much force and gives it the power to do useful

But as the air is let out of the tank through the reducing valve it
expands and loses its energy—or _latent heat_, as it is called—and
this makes it lose its power to keep on expanding to its greatest
extent and so it gets weaker and weaker.

To overcome this bad feature of compressed air, a heater is fixed on
the engine, and just as the compressed air reaches the cylinders of the
engine it is suddenly heated and this gives it all the expansive force
it needs. The heater consists of a small oil-burner which is so fixed
that the instant the torpedo is shot from the tube an electric spark
ignites the oil, and there is, in consequence, neither the loss of time
nor power.

The engine is often of the cylinder and piston type and is built quite
like an automobile engine, except that the _inlet valve_—which lets
the air into the cylinders—is disk-shaped so that it can operate all
the cylinders one after another. The exhaust ports open outside of the
torpedo, and it sets up a tell-tale white streak of bubbles on the
surface of the water.

Some torpedoes as, for instance, the Bliss-Leavitt, use a rotary
engine. But whichever kind is used, the power plant develops from 30
to 50 horsepower, and thus each torpedo weighs about as much and is as
costly as a high-priced motor car.

_The Propeller-Shaft and Propellers._—_The Propeller-Shaft._—The
engine drives the _propeller-shaft_, or, as it is called in England,
the _cardan-shaft_. To the end of this shaft outside of the torpedo is
fixed one of the propellers.

Another hollow shaft is slipped over the first shaft and one end is
connected to the engine and to the other and outside end of the shaft
another propeller is _keyed_ on. This shaft is driven in the opposite
direction to the solid shaft inside of it by _gears_ that is, a set of

_The Propellers._—The propellers have four blades; and the reason two
propellers are used is to counteract the force of each other. That is
to say, if only one propeller is used, the force of the blades striking
the water tends to tilt the craft to one side, and hence by using two
propellers this effect is very largely offset.

_The Steering and Diving Rudders._—The vertical or steering rudder
and the diving or horizontal rudders are hinged to a frame around the
propellers as shown in Fig. 42.

As it takes a lot of power to move these rudders against the varying
water currents, an air engine must be used to work them instead of
levers that are connected directly with the gyro, pendulum, or water
pressure controls.

=How a Torpedo Is Shot at a Ship.=—And now comes the most exciting
moment of all, and that is when a torpedo is shot from a submarine at
an enemy ship.

The latest type of submarine usually has eight torpedo tubes, four of
them fore, and four aft. These tubes are shaped as shown in Fig. 43,
and are built right into the hull of the craft.

Now, when we say that a torpedo is _shot_ from a submarine we do not
mean that it is _fired_ from it, for it does not explode until it hits
the ship it is aimed at, but we simply mean that it is _forced_ out of,
or _driven_ from, the tube of the boat.

[Illustration: FIG. 42. HOW A REAL TORPEDO IS MADE.]

The force that drives the torpedo from the tube is our old friend
_compressed air_, and this is taken from the _torpedo air tanks_ of
the submarine; they are placed just above the torpedo tube and are
connected with the rear part of it.

[Illustration: FIG. 43. THE TORPEDO TUBE.]

_Shooting the Torpedo._—Now let’s see just what happens from the
moment an enemy ship is sighted up to the time the torpedo hits it and

An up-to-date torpedo makes about 40 knots, and it will travel about
six miles before its compressed air is used up. But it cannot be aimed
and shot with certainty at a distance of over half a mile. So when an
enemy ship is sighted, the submarine creeps up upon her, with nothing
but her periscope out of the water, until she is within accurate
shooting range.

In the meantime the speed of the enemy ship has been calculated, the
depth at which the torpedo must travel to strike the ship below the
water-line has been determined, and the angle, or course, the torpedo
must take to hit the ship is figured out.

Due allowance must be made for the speed of the ship and the speed of
the torpedo to the end that the distance both will travel in a given
time may be known. Of course, if the ship is speeding along and the
torpedo is shot point-blank at her it will pass a good many yards
astern of her.

This operation is very much like that of rabbit hunting, in which you
do not fire directly at the running rabbit, but aim several feet ahead
of him, and he simply runs into the bullet or shot. So it’s all his
fault if he gets killed. Just so with the ship and the torpedo; for
instead of the torpedo running into the ship, the ship runs into the
torpedo, and so if the ship sinks it isn’t the fault of the torpedo—or
at least that is the way the German captain of a U-boat looks at it.

Before the torpedo is loaded into the torpedo tube the safety pin is
taken out of the firing pin and the butterfly-nut is loosened so that
it will unscrew easily. The torpedo is then slipped into the tube and
the _breach-block_ of the tube is closed. The compressed air is now
turned on at the torpedo air tank; when the air rushes into the torpedo
tube behind the torpedo, but the latter is kept from being forced out
by a lock.

_The Course of the Torpedo._—Next the captain sights his ship and finds
its speed and its distance from his own craft. To direct the torpedo
so that it will hit her target fairly, an instrument called a _torpedo
director_ is used. It is shown in Fig. 44, and this picture also shows
how the torpedo and the ship come together.


Now as the torpedo tube is fixed in the hull of the submarine the
_whole craft_ must be turned and aimed at the enemy ship. To do this
the _torpedo arm_ of the director is set parallel with the torpedo
tube; then the _torpedo speed scale_ is adjusted at the speed that the
torpedo makes and which is known.

The speed of the distant ship having been calculated, the _ship speed
scale_ is set at that speed and parallel to the ship’s course, and this
brings the sight arm in line with the observer’s eye and the line that
the ship is sailing.

When the ship crosses the line of sight the catch of the lock is
released, the compressed air blows the torpedo out of its tube, and
away she goes. The instant the torpedo has left the tube the engine and
other contrivances start to work and it then moves swiftly and surely
over a straight course.


Long before the torpedo reaches its goal the butterfly-nut drops off,
and so when it strikes the ship the firing pin which projects out of
the warhead is pushed back with a deal of force and explodes the charge
which either sinks the ship or cripples it.

=A Torpedo with a Cannon in It.=—Lieutenant Davis, of the U. S. N., has
invented a new kind of warhead for torpedoes, one that is even more
deadly than the style I have described.

It is made by placing a cannon in the warhead. When the torpedo
strikes the ship the cannon shoots a projectile clear through the hull
and into the inside of the ship, where it explodes. As the projectile
is fitted with a _time fuse_, it does not explode until it gets well
into the ship, and then it does far more damage than the old-style of
warhead, which explodes just as it strikes the hull. The projectile
is loaded with 250 pounds of guncotton or TNT but the warhead is not
loaded at all.

On the submarines that are now being built cradles which hold several
extra torpedoes are fitted to the decks, and in this way the number of
torpedoes which can be shot is increased.



Other Armament of the Submarine, Including a Complete Description of
How the Guns Are Made, Housed, and Used



IT would naturally be supposed that a submarine carrying eight or more
torpedoes is about as destructive an engine as human ingenuity could
devise; but not so, for there are other _munitions_ of warfare with
which it is equipped that make it even deadlier.

Now, the word _munitions_ means war materials of every kind—except, of
course, men and money; but on a submarine the munitions are limited
to (1) the _automobile torpedo_, which we have described in the last
chapter; (2) _rapid-fire machine guns_, and (3) _submarine mines_.

In the present war Germany has undertaken the gigantic task of sinking
all the merchantmen, not only of the Allies but of the neutral
countries as well, and it is this U-boat policy which has brought her
into a state of war with nearly every civilized country on the face of
the earth.

As the torpedo is such a costly weapon, it would not do to waste it on
sinking any but the largest ships, or those carrying valuable cargoes;
but the same policy of Germany, which is to starve out the Allies, also
calls for sinking the smaller craft, such as trawlers and unarmed
merchantmen, and this is done by means of _rapid-fire machine guns_.

These guns are mounted fore and aft on the deck of the submarine, and
they are used to bring down small ships and also to enable the undersea
craft to defend herself against _submarine chasers_, airplanes, or
occasionally when she is surprised by a destroyer or other armed ship
which may get within firing range and attack her before she has time to

The submarine mine is as old as, or older than, the submarine boat
itself; and it was probably the idea of fixing a bomb onto or planting
a mine under a ship that led to the actual building of the first
underwater craft.

The mine is not, however, an explosive destroyer which is used by
the submarine boat; for she could never get close enough to an enemy
ship in these days of electric eyes and ears to make use of one. What
the submarine does do is to play the peaceful rôle of planting the
mines—not with the idea of making two grow where only one grew before
but of making one ship less where there was one ship more, and this is
done by blowing up the enemy ships which may chance to pass over them.

=Arming the Submarine with Guns.=—From what has been said above, you
will see that by the use of rapid-fire guns poor prizes can be easily
and cheaply sunk; further, a small craft always makes a bad target for
a torpedo and thus the odds of making a miss and losing a torpedo are
very considerable. The use of rapid-fire guns is, then, a very good
stroke of business, everything considered.

Again, when a submarine is chased and has no time to dive, she is in a
bad way, for she is not fast enough to escape, nor can she stop long
enough to aim a torpedo at her foe. It is easy to see, then, why her
armament[23] should and does include a couple of rapid-fire guns.

=The Need of a Quick-Action Gun.=—With these conditions staring them in
the face, the designers of submarines have worked hard to equip their
craft with not only rapid-firing but, what is equally as important,
_quick-action_ guns.

To get a rapid-fire machine gun was easy, for this type had been built
by the Maxims these many years; but to get one that could be swung or
lowered under the deck so that it would not offer resistance to the
water when the submarine was running submerged, and then brought up and
into action quickly, was quite a different thing, and inventors are
still at work on it.

By this I do not want you to take it that submarines are not provided
with rapid-fire and quick-action disappearing guns at the present time;
and should you or I take a look at them we would say that they are 99
per cent. perfect and that there is no need for further improvement.
But that is because we are neither designers, nor builders, nor
officers of undersea craft; and do not forget, either, that better
things are always in order.

Now, there are two kinds of rapid-fire, quick-action guns used for
submarine armament and these can be told from each other by the way
they are brought into action. They are (1) the _spring_ action gun, and
(2) the _compressed-air_ action gun.

=The Spring Action Gun.=—This type of submarine gun is made by the
Krupps of Essen, Germany, who now are building the U-boats for the
Central Powers.

This gun is mounted on the deck, over an opening in it called a
_deck-well_, and this arrangement allows the gun to be stowed away in
it. This is done to get rid of the resistance the water would have on
the gun if it remained fixed on deck when the boat is running submerged.

Although the deck-well is closed with hatches it is not watertight, and
the fittings, such as the sights and range finders, are taken off to
keep them from rusting when the gun is in the well.

A diagrammatic sketch of the gun and its housing is shown in Fig. 46;
the gun is mounted on a swinging frame by _trunnions_, and the frame is
fixed to a pedestal. A strong spring in the bottom of the well supplies
the power needed to throw the gun up and bring it into position.

When housed in the well the gun lays on its back, as shown by the
dotted lines, and this presses down on the spring. The tension of the
spring is enough to force the gun up and into place the instant the
catch which holds it is released.

[Illustration: _Courtesy of Scientific American_


The sights and other attachments are fixed on the gun after it is
brought into position and the whole operation of raising the gun from
its well and putting on the fixtures takes just 20 seconds.


These guns have a bore of 75 _millimeters_[24]—equal to 3 inches—and 88
_millimeters_—equal to 3½ inches—respectively, and the shells they use
weigh in the neighborhood of 25 pounds.

=The Compressed Air Action Gun.=—This kind of submarine gun is used on
British undersea boats. It is mounted over a deck-well but inasmuch as
the gun is lowered into the well with all the fittings on it the well
has to be made watertight.

If you will look at Fig. 47, you will see how the gun is brought into
action. When compressed air is turned on in the cylinder, it forces the
plunger on which the gun is mounted up above the level of the deck.
The gun is fitted with fixed sights and a range finder, and is ready
for use the moment it has been brought into place above the deck, the
whole operation taking only 5 seconds.


The guns of the Allies’ submarines have bores of 3 and 4 inches, and
each one weighs nearly a ton. As a protection from enemy aircraft they
have a wide range and can, if needs be, fire a shot at 90 degrees, that
is, straight overhead.

=How a Submarine Lays Mines.=—The dangerous work of laying mines in an
enemy harbor by a submarine is not as spectacular as torpedoing ships
but it is an important part of the business of undersea craft.

A harbor which has been planted with mines to keep out enemy ships or
blow them up if they try to enter it is often remined overnight by
enemy submarines, and in this way a great deal of damage can be done to
friendly shipping.

But whether the submarine is used for mining its own or enemy harbors,
the outstanding feature of its work is that it does it all under water
and therefore the operations cannot be seen by spying eyes.

As we said in Chapter III, the mines are stored in a compartment in
the hull of the submarine and this can be shut off from the other
compartments by a bulkhead door. It also has a hatch opening through
the hull to the water outside, just as the door of a kitchen opens into
the back yard.

When the submarine has made its way under water to the place where the
mines are to be planted, the hatch is opened and the mine compartment
is allowed to fill with water. A mine layer in a diving suit can then
get in and out of the flooded compartment, take the mines one by one
through the open hatch, and place them in position.

Then there are mines which do not need to be set by a mine layer;
these are simply dropped through the hatch into the water and adjust
themselves as to depth. Other mines are made that are shot from the
torpedo tubes by compressed air and these are used for mining an enemy
harbor where the risks of having the submarine blown up is altogether
too great to take the chance.

=Kinds of Submarine Mines.=—Submarine mines—that is, mines that are
planted in harbors and other seaways, either as a protection from enemy
ships or as an offensive measure to blow them up—really have nothing to
do with submarine boats except that the latter are used to lay them.
But you ought to know about submarine mines, anyway, and so we’ll
digress a little and tell you something of them.

First of all, there are two distinct kinds of mines and these are, (1)
_contact mines_, and (2) _electrically controlled mines_.

As you can tell by its name a contact mine is one that is exploded
by the hull of a ship coming in contact with it—that is, by running
against it. This is the kind of mine that is most often laid by the

An electrically controlled mine is one that is exploded by electricity.
For this purpose a pair of wires are connected to it and these lead
along the bottom of the harbor to two _observation stations_ on the
shore; when the enemy ship gets directly over the mine the observers
close the electric circuit and the mine is exploded.

This is the way the _Maine_ was sunk in Havana harbor in 1898, but
the _Maine_ was not an enemy ship. The result of this rash bit of
foolishness led to the war between the United States and Spain, and the
loss of her island possessions.

=How the Mines Are Made.=—_The contact mine._—This kind of a mine
consists of a steel shell, or container, which holds the charge of high
explosive, the trigger mechanism which explodes it when a ship strikes
it, and the weights and cables needed to sink the mine to the right
depth. Air chambers are also placed inside the container, to give the
mine buoyancy; otherwise it would sink at once to the bottom of the

[Illustration: FIG. 48. A SIMPLE CONTACT MINE.]

In the contact mine the detonator is formed of an arm, or lever, called
a _striker_, and this projects through the shell to the outside. When
a ship strikes the arm it drives a _firing pin_ against a _percussion
cap_ and explodes it, and this in turn fires the explosive charge in
the mine. (See Fig. 48.)

_How the Contact Mine Works._—The way the mine works is like this:
Before it is taken out of the compartment of the submarine it is
adjusted to float at the proper depth.

When the mine is in the water a weight that it carries is released and
sinks to the bottom; the cable which connects the weight and the mine
together holds the mine in the right position, while the air tanks in
the mine make it rise as high as the cable will let it go, as shown in
Fig. 49.

After the mine is planted, the submarine steals silently and invisibly
away. When an enemy ship—or any other, for that matter, for the contact
mine is no respecter of ships—strikes the trigger of the mine, it
explodes the charge, and there is one less ship to sail the turquoise

_The Electric Controlled Mine._—To the end that a harbor can be planted
with mines which will blow up enemy ships and yet be harmless to
friendly ships, mines fired by electricity from the shore were invented.


Mines of this kind are made about like contact mines in that they
contain an explosive charge and a detonator, but they are much larger
and far more powerful, for they have to be laid on the bed of the
harbor, and instead of being fired by a pin striking a percussion cap
they are fired by an electric spark.

From each mine laid in the harbor a pair of insulated copper wires
run to the shore, and this electric circuit connects with two shore
stations at a distance apart and which with the mine form a triangle.
The electric circuit has a key in it at each shore station, and to
explode the mine both of these keys must be pressed down at the same


Each shore station has a telescope fixed in position so that its _line
of sight_ (shown by the dotted lines in Fig. 50) passes directly over
the mine. Now when an enemy ship approaches, each observer will see it
when it sails on or across his line of sight and he will press his key.
But it is necessary that _both_ observers see the ship at the _same_
time that it is at the point where their lines of sight cross, and
consequently directly over the mine, and when this happens they will
both press their keys, the circuit will be closed, the electric current
will fire the mine, and the ship will change her course to one straight
up and speed with all possible haste to the port whence no ship ever
clears again.



A Complete Description of How to Make a Model Periscope with Working
Drawings Together with a Simple Explanation of How a Real Periscope is
Made And Works



ONE of the gravest faults the pilots of the first submarines had to
contend with was that they were not able to see where their craft was

But like everything else that is needed for the welfare or warfare
of the human race, inventors got busy and began to scheme and to
experiment, with the big idea of making an instrument which would do
for the submarine what the eye does for the brain, and that is to _look
around_ with.

=How the Eye of the Submarine Got Its Name.=—Now, the eye of the
submarine is called a _periscope_ and before we go any further let us
find out how it came to get this peculiar name for then we shall know
more of what we are talking about.

The early Greeks used two words that were very common to them, and you,
too, will use them, before you get through with this chapter, just as
easily as they did. One of these words is _peri_ which means _around_,
and the other is _scopeō_ which means to _look_; so _peri_ plus
_scopeō_ means to _around look_, or, as we barbarians say it, _look
around_—which sounds better to us. And there you have the roots of the
word _periscope_.

=The First Submarine Eye, or Periscope.=—As in the beginning of all
things, good and evil, the first attempts to make an eye for the
submarine, or a periscope, were very crude, and as usual they were
nearly, if not quite worthless.

But the periscope was no exception to the first law of invention, and
that is that each attempt, however much of a failure it may have been
in itself, had the germ of a useful device in it; and from out of all
these efforts finally came that wonderful optical instrument, the

We say _wonderful_ because with it an observer in the conning tower of
a modern submarine, though it is all but submerged, can see everything
that is taking place on the surface of the water around the whole

The earliest trials at making a periscope were by using a simple
arrangement of mirrors of an “L” tube and each at an angle of 45
degrees. The best way to understand its construction is to make one for

=How to Make a Simple Periscope.=—You can get a lot of fun out of
this home-made periscope, and with it you can _out-sherlock_ Sherlock
Holmes, the great detective who was invented by Conan Doyle, for you
can see around corners, over fences, and even back of yourself just as
though you had a movable third eye, and without so much as ever being
seen yourself.

Make a tube of wood or cardboard 2 inches square and 12 inches long,
as shown in Fig. 51. Fit two square pieces of looking-glass into the
corners of the tube at 45 degrees—that is half way between the vertical
and the horizontal—and your periscope is finished and ready for use.


_How the Periscope Works._—When, now, you hold the long tube of your
periscope in a vertical position that is straight up and down, and
the light from an object, a person, or a scene at which the upper
horizontal tube, or _objective_, as it is called, is pointed, strikes
the first mirror, it bends the rays of light at an angle of 90 degrees,
when the light goes straight down the tube as shown by the arrows in
Fig. 51.

When it strikes the other and lower mirror, the rays of light are again
turned out of their path at an angle of 90 degrees, when they are
reflected out of the lower horizontal tube which forms the _eye-piece_.

If now you will place your eye to this end of the tube, you will be
able to look all around and see what you shall see. See?

=The Modern Lenticular[25] Periscope.=—The toy periscope which we have
just described, and which we hope you will make and use, does not
show what is going on at any great distance, and while this will not
interfere with your pleasure of using it, it mattered very greatly when
it was used as an eye for a submarine craft.

To be able to see farther led to the idea of using a telescope in
connection with the mirrors in the tube, and a periscope of this kind
was next made and tried out, and, let it be said, the results obtained
were a decided improvement as against those where mirrors alone were

=How the Telescope Is Made.=—You may or may not know it, but an
ordinary telescope, or _spy-glass_, as it is called, is made up of four
lenses, as shown in Fig. 52.

The purpose of the large lens in the front end of the tube—or _object
glass_, to call it by its right name—is to gather in the light of the
object and form an image of it. The small lens in the back end of the
tube is used to magnify the image formed by the object glass.

Now, when a telescope has only an object-glass and an eye-piece, the
magnified image of the object looked at is always upside down; this is
the kind of telescope that astronomers use in their star work and the
fact that the image is reversed doesn’t really matter anyway because
the man in the moon looks about as well when he is standing on his head
as he does when he is right side up.


But when you want to look at objects here on the earth’s surface you
want to see them as they are and not upside down. To _rectify the
image_, which means to make the eye see the object as it is, two more
lenses are placed in the tube, and so four lenses are used in all.[26]

_About the Reflecting Prisms._—The next big improvement in periscopes
came when a _total reflecting prism_ was used in the place of the
mirror at each end of the tube.

In _physics_ the terms _total reflecting_ means simply that _all_ of
the light that strikes a surface is reflected again without loss. While
a mirror will reflect only a part of the light that falls on it, a
_prism_ will reflect all of the light that enters it.

[Illustration: FIG. 53. THE REFLECTING PRISM.]

A prism is a three-sided piece of glass, if you forget to count the
ends, as shown at _A_ in Fig. 53. When a ray of light enters, say,
the vertical side of the prism it keeps on going until it strikes the
45-degree side of it; this side reflects and bends it and it passes out
of the horizontal side, as shown at _B_.

_The Construction of the Periscope._—Knowing now how a telescope is
made and what it does and also knowing what a prism is and how it
acts on light, all you have to do to understand the construction of a
submarine periscope is to take a good look at Fig. 54.

You will see that a prism is fixed in the upper end of the tube and
directly back of the object-glass; that another prism is fixed to
the lower end of the tube and back of the eye-piece; and that the
rectifying lenses of the telescope are set between these two prisms.
This picture also shows the path of the light through it.


These lenses and prisms are mounted in a tube about 4 inches in
diameter and 20 feet long. A horizontal revolving hood is secured to
the upper end of the tube and the horizontal eye-piece is fastened to
the lower end of it; a wheel is also fixed to the lower end of the
tube, so that the observer can turn the periscope completely around and
so scan the surface of the sea in any direction.

The periscope tube is placed in a slightly larger and very strong steel
tube, which passes through the deck of the conning tower and into the
latter, and it is made watertight by means of a _stuffing-box_.

The reason it is necessary to have a fixed outside tube is because the
force of the water, when the craft is submerged and is speeding along
under power, presses against the tube so hard that if only the inside
one were used it would bind; as it is, there is no pressure on the
inside tube and it can therefore turn freely at all times.

All recently built submarines have two periscopes, one of which leads
into the conning tower and the other one runs down into the navigating
room. Hence if one or the other is put out of commission by shell-fire,
or otherwise, the submarine can still see and find its way about.

_Gauging the Distance of an Enemy Ship._—An instrument called a
_telemeter_ (pronounced te-lem´-e-ter) is attached to the periscope
near the eye-piece, and the observer can by looking into it measure the
distance away of an enemy ship. This is done from the size of the image
it makes on the eye-piece.

Without this instrument the whole submarine, as large, as wonderful,
and as costly as it is, would be of small value, for by it the captain
is able to set his torpedo director very accurately and hence to aim
the torpedo so that it will make a sure hit.

[Illustration: _Courtesy of Scientific American_


=The Latest Type of Periscope.=—As the periscope just described, and
which is still in use on submarines, has a very limited _field of
vision_ at any given setting—that is to say, only about ⅙ th of the
horizon can be seen when the instrument is pointed one way—and as a
periscope which would show the whole horizon at the same time was
badly needed, a British firm of opticians set out to invent one.

The hardest part of the task was not to get a complete view of the
whole horizon at the same time but to prevent the rays of light
which form the images from getting mixed up with one another, or
_interfering_, and so producing a blurred and indistinct picture.

The new complete-view periscope differs from the older style only in
having a circular lens and prism; these gather in the light, bend the
rays and project them on down through the telescope lens until they
reach the lower prism when all of the images are reflected into the
eye-piece where the observer sees it as a circular picture.

This new improved form of periscope is of great value, for it gives a
safety-first view on all sides of the submarine at the same time and
the observer does not need to keep turning the eye-piece, and this is
of great value when a submarine is being closed in on by two or more
enemy ships.

It is a well-known fact that a large number of submarine accidents
have been caused by the limited range of view offered by the old-style
periscope, and in some cases the undersea craft has been rammed or sunk
by gun-fire from an enemy ship which she did not see.

The new periscope makes it impossible for a destroyer to creep up
on the submarine without being caught in the act. Nearly all of the
undersea craft now being turned out by all of the warring nations are
fitted with the new 360-degree[27] vision periscope.

=The Limited Use of the Periscope.=—Notwithstanding all these latest
improvements in the periscope, its use is quite limited, for it can be
used only when the submarine is running awash or partly submerged, and
since the tube of the instrument is only 20 feet high the distance to
which a ship can be seen is about five miles.

When running partly submerged the tube of the periscope sticks up and
out of the water about 10 feet, when the distance range of vision is
then cut down to about two miles, for the curvature of the earth’s
surface meets the line of sight and everything that is at a greater
distance than this from the submarine is below the horizon and hence

Should an enemy destroyer get within firing range of the submarine and
the captain of the latter craft wants to watch it, only the hood of the
periscope is poked up above the water; but of course the distance range
is again cut down.

The captain of a submarine has to contend with all these adverse
features of the periscope even on bright, clear days and when the sea
is calm; on dark and foggy days, when a heavy sea is running, the
periscope is next to useless, for the mist and spray gather on the
objective lenses and this makes it next to impossible to see anything.

Worst of all are the waves which break over the periscope, and this
prevents a ship from being seen even if it is only a little way off.
It is in rough weather that a submarine takes the longest chances; but
to put behind him any danger that may be lurking hard by, the captain
prefers to run undersea and come to the surface only when he has to.

A scheme to clear the moisture from the objective lenses is a device
called a _sprayer_. It is made and worked so that an observer at the
periscope can spray the lenses with alcohol. As water has a very great
liking—or _affinity_, as it is called—for alcohol, and as alcohol
evaporates almost instantly it carries the particles of water off with
it, and this helps to make the _seeing_ better.

=The New Enemy of the Submarine.=—A new enemy of the submarine has
recently made its appearance—an enemy that will make it use a periscope
of a new order.

This latest submarine destroyer is the airplane; and as the captain
cannot now see directly overhead except when his boat is running light
or awash, and the pilot of an airplane can see the submarine when it is
submerged to a very considerable depth, it is easy for him to follow
the undersea craft until she comes to the surface and then drop a bomb
on her.

A story of a running fight between an airplane and a submarine would
have put it in Col. Roosevelt’s _Ananias Club_ a few years ago, but
to-day it has all come to pass, and it looks now as if a good way
to break the backbone of Germany’s ruthless warfare on the sea is to
destroy the U-boats with a fleet of airplanes.



A Simple Explanation of All the Devices by Which the Submarine Sends
and Receives Signals, When on the Surface and Undersea



SINCE a submarine has an eye to see with, it is both proper and fitting
that it should have a tongue so that it may speak and ears so that it
may hear. In fact, an undersea boat is almost human.

The early submarine, though, was not only as blind as a cave fish, but
it was as deaf and as dumb as a snail; and since this was the case, it
had to do whatever talking was necessary by means of a deaf and dumb
alphabet, that is, by signaling with flags, or _wigwagging_, as it is

=The Tongue and Ears of a Submarine.=—The tongue of a submarine—or
rather tongues, for it has several—is the fanciful name I have given
to the means, methods, and schemes by which messages are sent from
one submarine to another submarine or to shore, and the ears are the
devices by which it receives messages from other submarines and from
shore stations.

There are two conditions under which messages must be sent from and
received by a submarine, and these are (1) when she is running light or
awash, and (2) when she is running submerged.

Now, most of the signaling systems can be used only when the submarine
is on the surface, and a couple of them can be used only when she is
under water.

Then, again, some systems are good only for daylight signaling, and
others for night signaling; others will cover very short distances, but
there are systems that will send and receive over long distances. But
whatever the system may be there will be found some weak point in it as
far as the submarine is concerned.

=Kinds of Signaling Systems.=—Since no one signaling system will meet
the rigid requirements of the submarine, several systems are used. When
the craft is on the surface, these are: (1) the _flag_, or _wigwag_,
system; (2) the _flashlight_ system; and (3) the _wireless telegraph_
system. When the submarine is under water the signaling systems used
are: (1) the _bell_, or _violin_, system; and (2) the _electric
current_ system—all of these will be described in order and as we go

=The Wigwag Way of Signaling.=—The oldest way of sending messages
at sea is by _wigwagging_, that is, using flags, and this system is
still in use in the navies of all nations for close range daylight

The way wigwagging is done is like this: Each craft has a signal book
which gives the positions of the flags and the meaning of them. These
flags are usually manipulated by a signalman (see Fig. 55) though
sometimes a mechanical apparatus called a _semaphore_, which has two
movable arms to hold the flags, is used.


Two flags are used, one in each hand or on each arm, and each position
of the flags means a letter of the alphabet, and so by showing the
flags in various positions to represent different letters words are
spelled out.

Another scheme that is used to signal with flags is by running, that
is displaying, a number of different colored flags on a _halyard_. The
combinations of flags—or to use the right word, _permutation_, which
means the number of different arrangements of a few flags that are
possible—are numerous and each permutation represents some word or a

Now, you might think that it would take a couple of hundred flags of
different colors to represent a message, and, further, that since there
are only eight colors which can be told from each other at a distance
of half a mile, signaling by colors could not be done.

But this is what you think, and not what you have figured out, for if
you have eight flags of different colors and display them, four at a
time, on the signal halyard you can make the surprising number of 1680
permutations; and this, you will allow, is enough to say anything that
you may have to say.

Although a _code book_ is found in every signalman’s outfit, he is a
chap who knows all the signals by heart and can send and receive flag
messages almost as fast as you can write down the words.

=The Flashlight System.=—There are two methods used for sending
signals at night over short distances, and both are done by means of
light; named, these are (1) the _colored light_ system, and (2) the
_searchlight_ system.

_The Colored Light System._—In this system incandescent electric lights
of high candle power are placed back of _bull’s-eyes_, or lenses, made
of colored glass, and these lights can be switched on and off and so
form combinations that spell out words just as the colored flags do.
This system is very much used for short range signaling at night.

_The Searchlight System._—A searchlight, that is an electric arc light
set in front of a silvered reflector, can be seen for long distances,
and so it, too, is largely used for night signaling.

The searchlight, which can be turned in any direction, has a movable
_shutter_, or metal disk in front of it, fixed to a handle, and when
this is worked up and down like a telegraph key, the shutter cuts the
light off and lets it shine forth accordingly.

By working the key, and hence the shutter, the light is broken up into
dots and dashes of the regular Morse telegraph alphabet, and these
short and long flashes are read by the operator on the other boat.

=The Wireless Telegraph System.=—The wireless telegraph has all the
other systems of signaling, when the submarine is afloat, beaten by

Among its advantages are (1) it can be used in the daytime as well as
at night; (2) the electric waves it sends out cannot be seen and this
makes it harder for an enemy ship to locate the boat it is on, and (3)
its signaling range is not cut off by the curvature of the earth.

_The Parts of a Wireless System._—There are three chief parts to every
wireless telegraph system, and these are (1) the sending apparatus,
or _transmitter_, as it is called; (2) the receiving apparatus, or
_receptor_, as some “high-brow” has named it; and (3) the _aerial
wire_, which is used for both sending and receiving.


The sending apparatus is made up of (a) a _source of current_, which on
a submarine is the storage battery; (b) an _induction coil_; (c) a
_telegraph key_; (d) a _tuning coil_; and (e) a _condenser_.

The receiving apparatus is formed of (a) a _tuning coil_; (b) a
_condenser_; (c) a _detector_; and (d) a pair of _head telephone
receivers_. A wireless telegraph set is shown in Fig. 56, _A_ and _B_.

Both the sending and the receiving apparatus can be connected with
the aerial wire by means of what is called a _throw-over_ switch, the
purpose of which is to connect the _aerial_ to the transmitter when
messages are to be sent out and to connect the aerial to the receiver
when messages are to be received. Thus only one aerial is needed.

_How Wireless Works_[28]—When a wireless message is sent the operator
makes and breaks up the current from the storage battery into dots and
dashes by means of the telegraph key.

_This interrupted low pressure current_ flows through the induction
coil and this changes it into a _high pressure current_ which makes a
_jump spark_. The spark in turn changes the high pressure current into
_high frequency currents_, or _electric oscillations_, as they are
called; and as these run forth and back over the aerial wire they set
up waves in the _ether_ which are called _electric waves_.

These electric waves are exactly like light waves, but they are so long
that the eye cannot see them. The tuning coil and the condenser are
used to give the waves whatever length the government says they must

When the electric waves that are sent out by the aerial of the
transmitting station strike the aerial which is connected with the
receiving apparatus of another ship and the operator is _listening in_,
the waves are changed back again into high frequency currents, and
these run to and fro on the aerial wire and up and down through the
tuning coil, the condenser and the detector.

The latter instrument changes the high frequency currents, which are
alternating, into an interrupted direct current; and these in turn
_energize_ the telephone receiver, with the result that the dots
and dashes sent out by the sending operator are reproduced by the
telephone receiver, when they are heard by the receiving operator who
is _listening in_.

The tuning coil and condenser enable the operator to _tune_ his
receiving apparatus to the length of wave which the transmitting
station is sending out, and this operation is called _tuning in_.

The wireless station of a submarine is usually located in the
navigation compartment. Although the aerial is neither high nor long,
messages can be sent to upwards of two hundred miles and received over
much greater distances.

Wireless allows the submarine not only to keep in touch with its _base_
but also to pick up and intercept messages from enemy ships, and though
the operator may not be able to decipher them it is possible for him
to determine in about what direction and at about what distance the
ship is.

[Illustration: _Courtesy of Hilbourne and Clark Mfg. Co._


Another use to which wireless is put is signaling between submarines
that are doing patrol duty at the same time but which are too far away
from each other to use either flags or lights.

Wireless telegraphy cannot, however, be used when the submarine is
under water, for water absorbs the electric waves in exactly the same
way that it absorbs light waves. But taken all in all, wireless is by
far the most important of all the signaling systems yet invented, and
it is the only one by which messages can be sent and received by either
day or night, over long distances and in any kind of weather.

=Underwater Signaling Systems.=—As I have said before, there are two
kinds of signaling systems used by a submarine when it is under water.

While both systems leave much to be desired—for neither can
begin to come up to wireless, either in ease of operation or in
signaling range—as they are the only known means by which underwater
communication is possible, there is nothing to do but to use them.

_The Bell or Violin System._—This is a signaling system that is widely
used on ocean going vessels of all kinds to send out warning signals in
thick weather.

It is a system in which a large bell or other vibrating apparatus sets
up sound waves which travel in every direction through the water; when
these waves reach another craft they are heard by means of a telephone
receiving apparatus.

Now, water will carry sound about ten times as far and four times as
fast as air; that is to say, if a bell is struck a blow in air and the
sound waves it sends forth can be heard a distance of half a mile, then
the same bell if it is struck when it is submerged in water will send
out waves to a distance of five miles.

[Illustration: FIG. 57. THE SUBMARINE BELL.]

The sending apparatus consists of either a bell (see Fig. 57), the
striking mechanism of which is worked by electricity, or of a large
saw-toothed wheel which revolves rapidly against a tight wire and
in consequence sets up a musical note. This latter kind is called a
_violin transmitter_.

Whichever is used is lowered through a hatch in the hull of the
submarine, and the bell is rung or the wheel is rotated by an
electro-mechanism, which sends out sound waves to distances of from 5
to 15 miles.

The receiving apparatus (shown in Fig. 57) is formed of an ordinary
_telephone transmitter_, and this is fixed in a small iron tank filled
with water and bolted to the inside of the skin of the hull. There is
one of these transmitters on each side of the ship, and each one is
connected with a battery and a pair of head telephone receivers placed
in the navigating compartment.


When the bell or violin of another submarine, or the base ship, sends
out its message in the Morse alphabet the sound waves, as you will see
by looking at Fig. 58, travel through the water and strike the hull
of the ship, go through its skin, set the water to vibrating in the
tank, and this, acting on the telephone transmitter, makes it vary the
electric current of the battery; the varying current flowing through
the telephone receivers reproduces the distant sound of the bell or the
violin wheel, and the operator on the submarine hears it.

The receiving apparatus also serves to detect the presence of an enemy
ship when it comes within torpedoing range by the sound waves set up by
and by which are sent out through the water by the rapid turning of the
ship’s _propellers_.

=The Electric Current, or Conductivity, System.=—In this submarine
telegraph system the water, which is a fairly good conductor of
electricity, is made to carry an ordinary battery current between the
sending and the receiving stations.

[Illustration: FIG. 59. THE UNDERWATER “WIRELESS.”]

Since the water conducts the current of electricity, it is easy to
see why it is called a _conductivity_ system. It is also called an
_underwater wireless_ system, but while it is _wireless_ in the sense
that there are no connecting wires between the two stations, you must
not confuse it with the _real_ wireless system, which uses electric
waves, for in the former the energy decreases as the _cube_ of the
distance and in the latter only as the _square_ of the distance.

_The Parts of the Conductivity System._—There are three principal
parts to this system, and these are (1) the _sending_ apparatus; (2)
the _receiving_ apparatus, and (3) the _submerged copper plates_ which
conduct the current from the sender into the water and from the water
into the receptor.

The sending apparatus consists of (a) a _source of direct current_, and
the storage battery supplies this; (b) a _reactance_, or _kick coil_,
as it is commonly called; (c) a _rotating interruptor_, and (d) an
ordinary _telegraph key_.

The receiving apparatus is made up of (a) a _telephone induction coil_,
and (b) a pair of _head telephone receivers_. All of this is shown in
Fig. 59.

One of the submerged copper plates is fixed to the bow of the
submarine’s hull, and the other is secured to the stern, in order to
get the plates as far apart as possible. These plates are connected to
a _throw-over switch_, so that either the sender or the receptor can be
connected to the plates as the operator wishes.

_How the System Works._—The instruments of the sending apparatus are
connected up as shown in Fig. 59. Now when a message is to be sent from
one submarine to another, the operator sets the rotary interruptor,
which is run by an electric motor, to spinning, and this makes and
breaks the current several hundred times a minute as long as he holds
the key down which closes the circuit.

The result is that each dot and dash he makes is formed of a large
number of separate currents, and as these flow through the reactance
coil, it gives each one a little kick and sends it out into the water
through the copper plates; the currents then spread out between and
from the plates in closed lines which extend to very considerable
distances, as shown in Fig. 59.

When these electric currents reach the plates of the receiving
apparatus on the submarine where the operator is _listening in_, they
flow up the wires and through the primary winding of the _telephone
induction_ coil; these broken up _direct currents_ flowing through
the _primary_ coil set up _alternating currents_ in the _secondary_
coil and also raise the _low pressure currents_ into _high pressure_
currents—that is, currents of a higher _voltage_, as it is called.

These alternating high pressure currents then flow through the
telephone receiver, and by varying the strength of the magnet of the
latter the dots and dashes of the sending station are reproduced and
the receiving operator hears them as a musical buzz.



How the Crew of a Submarine is Signed, Slept and Fed. The Mother or
Base Ship and Its Uses. The Complement of the Submarine; How New Men
Are Trained, and the Duties of the Crew



YOU will remember, back there in the first chapter, we told you about
Fulton’s submarine and how one man operated it, so naturally he was his
own superior officer and able-bodied seaman both rolled into one.

Since those early days of underwater navigation wonderful advances have
been made, not only in submarine construction, but in the crew that
mans her as well, for not only are there many men in the crew of a
submarine of to-day, but each man is highly trained for the work he has
to do.

At the present time the _personnel_, which means the force of men
employed as well as their fighting qualities taken as a whole, includes
a list of no less than 48 officers and seamen, and each and every one
of them is a picked man. The smaller submarines, of course, carry a
smaller _complement_ of men, for there is neither as much work to be
done nor is there room to bunk them.

=Conditions on Early Submarine Craft.=—What with the great array of
instruments, apparatus, and machines that must form the equipment of
the submarine to make her an efficient fighting unit, there is but
little space left in her for her crew, and this was especially so in
the early days.

Owing to the fact that space was, and still is, at a premium, the crew
of a submarine does not list a man who has not one or more important
parts to play in the actual operation of the boat; for every addition
to the crew means that much less comfort for each one, and interferes
moreover, with the carrying out of orders in a rapid and effective

=When Crews Were Hard to Sign.=—There were no conveniences provided on
the first submarines for their crews; indeed, as we look back now on
those pioneer attempts, it seems verily as if no thought at all was
given to the health and safety of the men who manned them.

It was enough, albeit, to get a boat that could be submerged and which
stood a fair chance of coming to the surface again; so of course there
was not enough air, and the little there was was bad; the quarters, if
there were any at all, were very small and close, and there was a deal
of danger attending the most ordinary maneuvers.

Now, the able-bodied seaman knew all these things only too well, and,
what was more, he had heard tall yarns spun around of the terrors of
the new and strange craft, and these did not tend to strengthen his
desires to hurry up and enlist in that arm of the naval service.

When the various governments began to take a real interest in the
submarine and to keep up an active flotilla, they began to realize
that unless the comfort and the safety of the men were looked after
better than they had been in the past the submarine service would soon
be shorthanded and badly crippled.

So as a sop for the bad conditions which the crew must stand, the men
were offered a large _bonus_—that is, extra money besides the regular
pay—and also extra privileges. In truth, the offers were so generous
and alluring that it was not long before seafaring men began to rush
to the call, and from that time to this there has never been the least
trouble in getting crews for undersea fighting craft.

As the construction of the submarine moved on apace and it grew in
size, and as new inventions and improvements were made to supply pure
air and enough of it, all the discomforts vanished, until a berth on an
undersea craft is as agreeable, nearly, as it is on a man-o’-war.

=What the Base-Ship Is For.=—While, of course, the chief object of a
submarine is, as you can tell by its very name, to travel undersea when
needs be, it is, as you have already learned, not fitted to run for
more than forty-eight hours at a stretch when totally submerged, and
as a matter of fact it spends most of its time afloat and in the awash

From this you will see that living on a submarine is for the greater
part of the time just about the same—though a little more confined—as
it is aboard any other craft. Her actual cruising _radius_—that is the
distance she can sail from her base of supplies—is seldom more than
2,500 miles; and she is limited to this mileage simply because of the
lack of storage for the food and fuel she needs.

For this reason every submarine must have a supply base, and this
usually is a ship which is supplied with the necessities of life and
power. The _base-ship_, as it is called, is also a _floating dock_,[29]
has a complete machine shop, and every other conceivable thing that she
needs to take care of her flotilla of submarine children. A _mother
ship_ is shown in Fig. 60.

The base-ship follows after her submarines, not directly on their
heels, but so that they will be within easy cruising distance of her.
It may seem that 2,500 miles—nearly the span of the Atlantic—is a long
distance, and it is for a submarine to make one continuous trip; but
ten short runs of 250 miles each will use up her supplies and then she
will have to return to her base for more.


In times of peace a submarine never strays far from her base-ship,
indeed, she spends most of her time laying alongside of her except
when at practice. At such times the submarine and the base-ships are
considered _integral_[30] parts of each other, and under these
conditions most of the crew stay aboard the ship.

Thus it is that a submarine sailor’s life is nearly all spent above
water, and it is not such an unhappy one at that.

=How Men Are Trained for Submarine Duty.=—The base-ship is also used
as a training ship for _rookies_—that is green hands—and on it they
are let into the secrets and mysteries of the working, sailing, and
fighting machinery of the submarine.

The rookies are taken in hand by the officers and the more highly
skilled sailors of the submarine and drilled in whatever they are to do
until it becomes second nature to them, for a _fluke_ of any kind might
spell disaster for the whole crew and craft.

=The Complement of a Submarine.=—The word _complement_ (notice that it
is spelled with an _e_ instead of an _i_) means not some pretty bit of
flattery but the full number of men that is needed to man the boat.

The complement of a submarine is not very different from that of a
torpedo boat or other small naval craft. There is, first of all, the
_commander_, or _commanding officer_, who is in charge of and is
responsible for the crew and his boat.

His word is law and he is as able a navigator and _tactician_—as an
expert in directing a submarine, with skill and shrewdness is called—as
it is possible to get. His brain is the master brain of the mighty
craft, for it is he who plans what his crew must do, and when they
must do it to the end that the enemy ship shall be sunk.

Then there are the officers under him—_lieutenants_ (pronounced
_lef-ten´-ants_, with the accent on the second syllable, by stage folks
in naval plays)—and these correspond to the first and second mates,
etc., of a sailing ship.

These officers are also thoroughly competent navigators, and should
anything happen to their superior officer, any one of them could take
command of the submarine and give a good account of himself.

The rest of the crew is made up of engineers and oilers, torpedo-men
and gunners, wireless and signalmen, cooks and able-bodied seamen. The
engineers not only must know how to run the engines to get the most
power with the least fuel, but they must be machinists of the highest
class in order to make repairs of every kind should the boat be damaged
by shell fire.

The torpedo-crew, as the men who have charge of the torpedoes are
called, take care of these mighty missiles from the time they are
lowered into the hull from the base-ship to the moment they are shot
from the tubes on their courses to sink the enemy ships.

This crew also takes care of the trimming tanks, which must, as we
have explained before, be filled with water to offset the effect of
lightening the submarine by the sudden discharge of the torpedoes. The
gunners, of course, look after the guns and are expert _gun pointers_.
All of the new submarines are equipped with _wireless_ and this is
worked by two or more experienced wireless men who are on constant duty
while the boat is afloat and who operate the conductivity telegraph
system when the craft is running submerged.

The submarine is kept in constant touch with the _mother ship_, as
the base-ship is sometimes called, and as the latter has a much more
powerful sending apparatus it can, in turn, communicate with the land
either directly or by relaying the message by another ship.

The wireless operators also keep busy listening for the first faint
signals sent out by enemy ships which may come within range of their
instruments, and though they will not be able to read the messages
if they are sent in _cipher code_[31] they can at least know of the
proximity of the ship.

=Breaking in Raw Recruits.=—When there is peace on earth and good will
toward men the submarine never gets very far away from its base-ship,
about its only excursions being for drill and practice, which is made
up of _maneuvering_ the submarine and torpedo practice.

[Illustration: _Courtesy of Leslie’s Weekly_


To _maneuver_ the craft means to make adroit moves and changes of
position, that is, the boat is put from the afloat into the awash,
submerged, and totally submerged conditions by and for the benefit
of both the new men and old hands.

The submarine’s _place at sea_—that is, her _longitude_ and
_latitude_—is found solely by _log distances_ and _compass courses_
while the boat is running submerged, and her course is corrected for
_drift_ and _leeway_; navigating the submarine by these means is called
_dead reckoning_.

Torpedo practice consists of firing torpedoes with _dummy heads_, that
is, heads which do not contain a charge of explosive, at floating
targets which the submarine or a lighter tows out to sea and anchors
fast. Whether the torpedoes hit or miss they come to the surface after
having been shot and are picked up again and returned to the submarine.

By constant practice the men of the torpedo-crew become highly skilled
in hitting the target with the cigar-shaped projectile, and they are
not allowed to get rusty for want of constant practice.

To add to the knowledge which actual practice gives the raw recruits,
as well as the more experienced men, the officers lecture to them
on every subject that has to do with the design, construction, and
operation of every working part of the submarine.

In this way the crew is trained to do their several individual duties
with clock-like precision and is fit and ready at a moment’s notice to
handle the craft for all she is worth when war comes.

=The Conditions in War Time.=—When the dove of peace has had its
tail-feathers plucked out by the god of war and the enemy nations are
arrayed in battle formation against each other, then the submarine and
her crew are welded into a destroying unit of the most treacherous and
dangerous kind that the sea has ever known.

The conditions on board a submarine are quite different in war time
from those when the nations are at peace. In the first place, when
submarine chasers and aircraft are scouting the seas in search of
underwater boats it is not only dangerous but often impossible for a
submarine to keep in touch with the base-ship by wireless.

We say _dangerous_ because wireless messages flashed forth and back
would betray its presence to an enemy ship, and we say _impossible_ in
virtue of the fact that the craft often has to run under water for as
long a time as she can stay down.

When cruising on the surface the sharpest lookout must be kept every
moment of the time for an enemy ship, which may be torpedoed if it is
a merchant vessel, or the submarine must dive and get away from it, if
it should be a chaser or other kind of armed and armored boat that is
looking to sink her.

Under these strenuous conditions the crew is keyed up to the highest
pitch and the severest discipline is maintained on board. Torpedoing,
diving, submerging, and all the other drills that have been learned
under the easy routine of make-believe war now become stern realities
upon which the very safety of the submarine depends and hence the lives
of the crew.



How the Submarine Works with the Fleet as a Means of Defense and
Offense and as a Scout. Its Use as a Blockader and A Weapon Against



WHEN the naval powers were waking up to the fact that the submarine was
worthy of some consideration, undersea tactics was a thing that was yet
to be invented.

These early craft had a very short range of travel and because of their
poor construction and lack of power they were not at all adapted for
ocean-going, hence they could not accompany the fleet of warships on
their maneuvers.

They were, however, thought very well of for coast patrols, and this
was the duty given them to perform; each submarine had a stretch of
coast which it was to watch and tactics and maneuvering were not needed
for this service. Even when it was expected an attack might be made,
the only thing that was required of them was to be on the lookout,
signal the forts on shore, dive and get out of harm’s way.

But as the size, range, and speed of the submarine was increased she
gradually took her place along with the _auxiliary[32] craft of the
fleet_, or _squadron_,[33] and began to take part in the maneuvers
with it. It was then that certain fixed duties were assigned to her,
and her relation to the other boats became more clearly defined and
definitely fixed.

As late as the Spanish-American War, and that was only a score of years
ago, the submarine played but a sorry part. A few years later, however,
when the Russo-Japanese War was fought, the underwater fighting craft
showed for the first time in the game of naval warfare the kind of
stuff it was made of.

In the years of peace and prosperity that passed between the end of
the Russo-Japanese War and the beginning of the great world war of the
nations that is now going on, the submarine was experimented with and
improved upon until it has thrown all the other types of naval craft,
from the _dreadnaughts_ on down into the shade where there isn’t any

The result of it all is, as you probably know, that the submarine
has developed a kind of warfare all its own and which it carries on
entirely without help. Imagine, if you can, that in the greatest war
that has ever been waged giant battleships are sewed up in the harbors
of the enemy while her submarine flotillas are everywhere at sea
and carrying on a most effective blockade! Such is the rise of the

=The Uses of the Submarine.=—There are two chief uses to which the
submarine is put, and these are (1) as a _reserve defense_ or _offense_
for the fleet, and (2) as an _offensive weapon_ for the purpose of
maintaining a blockade.

_How She Works with the Fleet._—In the first instance, that is, where
the submarine is used as a means of defense and of offense with a fleet
or squadron, her tactics are well defined and clear-cut.

Her activities under these conditions are rather limited, for she is
not built speedy enough to keep up with a swiftly steaming fleet. This,
then, in the very nature of things, keeps the submarine from playing an
otherwise all-important _rôle_ of scout-ship.

Further, this lack of speed on her part prevents her from engaging
in battle as an actual part of the fleet or squadron, for very often
it is the speed of the attacking men-of-war that makes for victory,
and a flotilla of submarines that lagged behind would prove more of a
hindrance than an aid.

But what the submarine can and does do to great advantage is to attack
an enemy fleet either as a defensive or an offensive measure, depending
on the relative strengths of the fleets which oppose each other.

_The Submarine Flotilla as a Means of Defense._—Now let us see first
what happens when a fleet with a flotilla of submarines attacks another
fleet which is without them.

If the attacking fleet is the weakest—that is, its guns are the
lightest—then the submarine flotilla will take a defensive stand,
though the opposing fleet is making the attack. The submarines will lay
off to the rear of the attacking fleet, and then if the gun-fire from
the enemy waxes so warm that the attacking fleet is forced to retire
the submarines are in a good position to aid the fleet in its retreat,
as shown in Fig. 61.


Now, as soon as the pursuing ships come within range, the submarines
let go their torpedoes at them and these either blow them up, cripple
them, or scare them off. In a maneuver of this kind the commander of
the fleet executes his retreat in such a way that the heavier-armed
pursuing fleet must pass near his submarines, which are usually
submerged and are therefore invisible.

_The Submarine Flotilla as a Means of Offense._—If, now, the attacking
fleet is stronger than the defensive fleet, then the submarines of the
attacking fleet will also take an offensive part. In this case the
submarines will take up a position to the rear of the defensive fleet.

The commander of the attacking fleet will then use such force on the
enemy fleet that it will retreat along the path where the submarines
lay, when they will, of course, torpedo them, as shown in Fig. 62.

Both these methods of attack have been used with signal success in the
war that is now going on.


=The Submarine as a Scout.=—Although the submarine is useless as a
scout for a swiftly moving fleet still it can render great service as a
scout on its own hook.

By way of illustration let us suppose that the enemy has a harbor that
is well protected by forts and guns, that her fleet is laying to in
it, that we want to know how many ships the fleet is made up of, and,
finally, what class of ships they belong to.

It is the duty then of a submarine to get into the harbor and take a
general survey of the situation. You may wonder how the craft is to do
this, since the harbor is mined; but by skilful handling, the captain
will usually get through safely, find out all that he wants to know and
run out again.

Besides thoroughly reconnoitering a harbor, the submarine can lay a
few contact mines, as we explained in a chapter that has gone before,
in positions of which the enemy fleet is in entire ignorance and which
will be more than likely to result in the destruction of at least a
part of the fleet.

Further, the submarine is used to destroy fields of mines which have
been laid by the enemy in a harbor. This is done by mines thrown from
the torpedo tubes among those that have been planted and which explode
by the concussion.

=The Submarine as a Blockader.=—The most important use to which the
submarine has ever been put and one that was never thought of seriously
until the present conflict is that of a _blockader_.

Ever since the beginning of this war Germany has realized the
tremendous need of keeping the _neutral_[34] countries from supplying
the Allies with munitions and food supplies, and she has prepared for
years a blockade of a new and very effective kind, and this is by
destroying merchantmen by submarines.

England and the other Allies have done the same thing with the Central
Powers—which is not a very hard thing to do because Germany’s fleet of
warships is cooped up in her various ports and dare not venture forth,
and so the task is left entirely to her submarine flotilla.

And what makes it still harder for the German submarines is that the
Allies keep on the constant watch for these enemy undersea craft, and
this they do with their _submarine destroyers_, and the United States
is after them with her _submarine chasers_, to say nothing of England’s
aircraft attacks.

Altogether it is very hard for the enemy submarines to keep in touch
with their respective bases or to receive orders as to their courses of
action. When on blockade duty, then, the captain of a submarine is in
very truth, the commander of his craft and it is strictly up to him to
determine what her tactics shall be.

As long as he does his work well, which means that he sinks a fair
number of all the ships that enter his zone, his superior officer,
wherever he is, will have no quarrel with him as to when or how he does
the work.

So you see the tactics used by the captain of a submarine while doing
this kind of work depend entirely on the conditions he encounters at
the moment, and on the quick decision and judgment of the captain
depends the success or failure of the attack.

=How a Submarine Attacks a Merchantman.=—As a general thing submarines
travel alone when merchantmen are to be torpedoed.

The sea is mapped out into _zones_, as certain areas or parts of the
sea are called, and each zone, or part, is usually assigned to a
single craft; the submarine patrols this zone constantly, and the
captain and his officers keep their weather eye open for passing
merchantmen or vessels which might in any way aid or carry supplies to
the enemy.

To do this the captain of the submarine stops every ship that comes
his way and has her papers and cargo examined, and in this way finds
out whether the ship is what she seems to be or if she carries
_contraband_—that is arms, ammunition, and war supplies of any kind—or

The way in which this interesting procedure is done is as follows:

The submarine, let us say, has sighted a ship, and seeing that it is to
all intents an unarmed merchantman she rises to the surface and trains
her rapid-fire guns on the craft. Next she signals the ship to stand by
and at the same time she runs toward her.

Now the captain of the ship has three courses open to him: (1) to put
on full speed and try to get away, trusting to luck to prevent his
craft from being shot full of holes or torpedoed; (2) to take a still
greater chance and try to ram the submarine with the sharp, steel-shod
bow of his ship and so either disable or sink her, and (3) to comply
gracefully to the request and heave to.

If the latter is done, the _collapsible boat_ of the submarine is
rigged up and a couple of the officers and crew row over to the ship,
when they are hauled aboard and go through her. Should they find
nothing of a suspicious or contraband nature, the boat returns to
the submarine and the ship is allowed to go her way.

[Illustration: _Courtesy of Leslie’s Weekly_


But, on the other hand, if contraband is found on board, the captain
of the submarine will do one of these two things: (1) he will warn the
crew of the enemy ship that he is either going to open fire on her with
his guns or torpedo her, and to take to the life-boats, or (2) he will
sink her without warning if the whim so seizes him. Often the captain
of the destroyed craft is taken aboard the submarine and held as a

=When Submarines Attack in Pairs.=—Another strategic scheme that is
used to torpedo enemy craft is to work submarines in pairs.

This is not done, as a rule, except where the ships may, in virtue of
their armament, prove dangerous to a single submarine and then they are
sunk without warning.

Tactics of two different kinds are used in the actual stopping of the
craft. The first is for the submarines to lay off from each other at
a distance of from three to five miles (as shown at _A_ in Fig. 63).
Then when the submarine, with her periscope above water, spots an enemy
ship, she signals to the other submarine, which is submerged, and gives
her the exact speed and course of the armed vessel.

The submarine with her periscope above water cannot be seen by the ship
because she is too far off, and the nearby submarine cannot be seen
because she is totally submerged; so the first submarine directs the
second submarine how to train her torpedo tubes on the enemy ship and
when to shoot the torpedoes at her. By these tactics a ship can be sunk
without either of the submarines being seen.

The other and second way by which an armed ship can be attacked is by
having a pair of submarines travel together, one directly over and
separated from the other by a distance of only twenty or thirty feet
(as shown in Fig. 63).


Now, when a ship is sighted by the craft nearest the surface she comes
up boldly and demands the hostile vessel to heave to. Should, instead,
the enemy ship open fire and cripple or destroy the submarine, the
submerged submarine takes up the fight and shoots a couple of torpedoes
at the aggressive ship and so puts an end to her, if possible.

The tactics we have told you about are only a couple of the many used
by present-day submarines; we should like to go on and write a book
about them but if we did we’re afraid the Imperial German Government
might not like it, so we’ll stop here.



A Description of the Allied Submarine Chasers Both on Sea and in the



IT is the boast of Germany that she will win the present war by sinking
not only all of the ships of the Allies, but those of any other country
which may trade with them.

Now, the United States demands the freedom of the seas for every
American citizen and for every ship that flies the stars and stripes
and to make good this demand is what brought us into the war.

If Germany could destroy all of the merchantmen of the Allies—and we
are now one of them—as she wants to do, she would doubtless be the
victor. She hopes to but will never be. The blockade by her submarines
is growing more and more serious and many plans and schemes have been
put forth to outwit, offset, or to break it down by destroying her

There are at the present time[35] only about thirty million tons of
_shipping_[36] in the world which can be used to supply the Allies of
Europe with munitions of war. The German U-boats are picking off ships,
both neutral and otherwise at the rate of half a million tons a month,
and at this rate of destruction shipping cannot last more than a few
years. Hence the great need of breaking the blockade and of doing it

=Schemes for Outwitting the Submarine.=—Many plans have been thought of
and tried out to get the best of the tough old submarine and so defeat
it; and among these are:

(1) To build ships that are so heavily armored that they can withstand
the attack of torpedoes.

(2) To build ships which have a light enough _draft_ and are speedy
enough to outdodge and to outrun the swift torpedo.

(3) To outrig the ships below the water-line with nets which prevent
the torpedoes from striking the hulls hard enough to explode them.

(4) To fit the ships with wireless ears which will detect the presence
and determine the position of the submarine before it gets within
torpedoing range and so give them a chance to escape.

(5) Any number of other impracticable schemes.

Now, you may ask why these schemes are useless. Among the reasons are
these, (a) steel armor has yet to be made that will withstand the
violent explosive power of the torpedo, (b) ships with a draft light
enough and a speed great enough to get out of the way of a torpedo
could not be used as freighters, (c) nets on ships make them slow and
unwieldy, and as soon as they were used the torpedoes were fitted with
steel cutters which enabled them to go through as easily as before,
(d) the art of wireless has not yet advanced to the point where it is
possible for a ship to detect the presence and position of a submerged
submarine, (e) every other scheme that has been put to the acid test
has had a glaring fault in it.

=Plans for Destroying the U-Boats.=—Now, the right way to break the
German blockade is to destroy the U-boats, and plans along this line
have been devised and carried out with better success.

The submarine can be destroyed in several ways. Among the most
important are (1) by laying mine-fields; (2) by arming merchantmen with
rapid-fire guns; (3) by destroying the base-ships which mother the
submarines; (4) by hunting them down with submarine chasers, and (5) by
dropping bombs or shelling them from aircraft.

_Laying Mine Fields in Harbors._—This plan is very good for protecting
harbors against submarine attacks; but as nearly all the merchantmen
are sunk from 200 to 300 miles off the coast, the use of mines for the
protection of shipping is very limited.

_Arming Merchantmen with Guns._—Arming merchantmen has met with some
success, but as a matter of fact it is a very uncertain means of
protection, and the large number of armed ships which are sunk weekly
shows that the plan is weak.

As a merchantman, or freighter, is usually a slow craft, and a
submarine can easily out-maneuver it even when the submarine is on the
surface, and when she is submerged she cannot be seen, it must be clear
that ordinary rapid-fire guns cannot easily hit her.

_Destroying the Mother Ships._—To destroy the base-ships is, though it
may sound like a _paradox_, one of the best and at the same time one of
the least practical plans of getting rid of the submarines that infest
a certain zone.

It must be clear if the base-ships are destroyed that the submarines
they mother would speedily come to an end. Knowing full well that the
Allies would try to find out her bases, both on land and sea, Germany
has hidden most of them well, and those that are not hidden are
protected by guns of such caliber[37] as to prove a source of danger to
even a fleet of first line dreadnaughts.

Since the bases are too hard to find and too hard to destroy when once
found, other easier and more practical plans have been devised, tried
and found fairly successful.

=Kinds of Submarine Chasers.=—And now we come to a class of naval craft
to which the name _submarine chaser_ has been given, and she has proved
to be the best and most practical plan yet worked out to kill off the

There are two very different kinds of submarine chasers, and these are
(1) boats which travel on the surface of the water, and (2) craft which
travel through the air. The first kind only, though, is called a
_submarine chaser_, while the second kind may be either a _dirigible
balloon_ or a _warplane_.

[Illustration: _Courtesy of Leslie’s Weekly_


_The 80-Foot Submarine Chaser._—The submarine chaser is simply a boat
whose success as a destroyer depends on four _factors_, and these are
(a) how fast she can go; (b) how light her draft is; (c) how well she
is armed, and (d) how fast she can be built.

Two kinds of these chasers have been built, and both have shown their
real worth. The first is known as the 80-foot submarine chaser. 550 of
these noble craft have already been built for England and sent over to
operate against the U-boat in British waters.

They are powered with gasoline engines and are built just about like
the high-speed pleasure boats that are now so common here on this side
of the Atlantic, that is, they have a three-quarter cruising cabin and
cockpit as shown in Fig. 64.

They are very seaworthy, and the powerful gasoline engines installed in
them give them speed enough to outrun the fastest submarines that have
yet been built. Each one carries a rapid-fire gun of the 3-inch type.

_The 110-Foot Submarine Chaser._—The only fault with the 80-footer is
that its small size makes it impossible to store away enough fuel to
give it a large cruising radius, and so a new type of submarine chaser
is being built which is 110 feet long. Its general appearance is shown
in Fig. 65.


[Illustration: FIG. 65. 110-FOOT STEAM SUBMARINE CHASER.]

This boat is powered with steam engines and oil-burning boilers which
drive the chaser at the very fast speed of 25 knots. The craft is
armed with a battery of two 3-inch guns mounted on the fore and aft
decks. The large size of this chaser makes it easy for it to cruise
for long distances, while its speed is 8 knots faster than that of the
fleetest submarine and this makes it a foe that is truly to be feared.

=How the Chaser Chases a Submarine.=—The way a submarine chaser chases
a submarine is like this: each chaser is given a certain area of seaway
to patrol. This she does, and if she is lucky she will soon see the
periscope of an enemy submarine poking its hood above the water to take
a peek around the horizon.

This is the signal for the chaser to bear down on that periscope at
full speed, the gunners doing their level best to hit the periscope or
any other part of the submarine which shows itself above water.

As it takes time for the submarine to dive or to get her own guns into
action, the chaser stands a pretty good chance of either crippling or
even sinking her. Further, the submarine cannot use her torpedoes on
the chaser, for the latter craft is so short and has such a shallow
draft that her hull does not offer much of a target for a torpedo, even
though she were standing still, and much less when she is bearing down
on the submarine at full speed.

Every once in a while a chaser is able to surprise a submarine when
she has come to the surface for a breather and to recharge her storage
batteries. When this happens it is simply another case of the cat
eating the canary.

If the submarine is within two miles of the chaser she cannot get ready
to dive and she must either get her own guns in action or else she
must try to outrun the chaser, getting ready to dive as she runs and
trusting to the Kaiser that she may not be hit in the meantime.

This last course proves disastrous to the submarine nine times out of
ten, and so she usually gets her guns into action and a regular little
sea battle is fought right then and there.

=Shooting the Guns of the Chaser.=—Having found, chased, and caught the
submarine, the next thing to do is to put her out of commission. On the
guns with which the chaser is armed, and on her gunners, depend to a
large extent the success or the failure of the attack.

A gun which had a long range and a _flat trajectory_[38] was quick
in action, and rapid-firing, was thought to be all that a gun should
be for submarine execution; and it was all right for shooting at
conning towers and similar targets which showed themselves above the
water-line, but it was useless for a gun of this kind to try to hit
anything that was even a few feet under water.

The reasons for this are somewhat deep and scientific but if you will
read carefully, look at the diagrams shown in Figs. 66 and 67, and do
a little thinking as you go along you will be able to _visualize_ the
whole thing—that is, to see it.


Now, the way this gun was made was to _rifle_ the barrel of it, and
this gave a turning motion to the projectile when it was fired, that
is, it spun around on its _long axis_, and the _trajectory was flat_,
which means that the path of the projectile in its flight from the gun
to its target was only slightly curved.


Both of these things made the projectile deviate from its course the
instant it struck the water, or _ricochet_ (pronounced rik-o-sháy)
as it is called; that is, it bounced from the water in exactly the
same way that a flat stone skips along when you throw it close to the
surface of a pond or lake.

The right kind of gun to use on submarine chasers is not rifled, and
the projectile should be given a trajectory, or path, that is much
the same as that of an arrow; the result is that a shot can be fired
at a submarine which is submerged to a depth of 20 feet or so and be
effective because the curve of the path is such that the projectile
drops straight, or nearly straight, down on the submarine and
penetrates the water as shown in Fig. 67.

=Submarine Air Chasers.=—Besides the submarine chasers just described,
there are two other kinds that have shown great possibilities as
destroyers of undersea craft. These are (1) the _airship_, or dirigible
balloon, and (2) the _airplane_, and it is more than likely that in the
near future, should the war keep on, the latter craft alone will be
used for submarine chasers.

Where a boat chaser cannot see a submarine at all when she is
submerged, an airplane can fly directly over her, follow her every
movement, and see her when she is at a considerable depth. (See Fig.

As the airplane is much more steady in the air than a submarine is
on the water and as the former is much quicker and speedier than the
latter, a battle between these two very different kinds of craft is an
unequal one with the odds greatly in favor of the warplane.

=A Way to Lift the U-Boat Blockade.=—Here, then, is a real, ready way
that the submarine can be destroyed and Germany’s blockade lifted. To
put an end quickly and for all time to the U-boat menace, the United
States ought to build several thousand airplanes at once and arm these
with bombs and rapid-fire guns like the Lewis[39] and send this fleet
to patrol the seas.


If this were done there wouldn’t be enough U-boats left in a month’s
time to flag a Norwegian fishing trawler. So the thing for your Uncle
Sammy to do is to build a great fleet of airplanes, and in the shortest
possible time.

There is still another way to break the blockade, and this will be
described in the next chapter.



The Adventures of the “Deutschland” and Some Schemes for a Merchant
Submarine Service



IT is less than twenty years agone that the first five baby Hollands
were built in this country for, and delivered to, England, and
from that time dates the beginning of the art of modern submarine

Since then the size, speed, and cruising radius of each succeeding type
of submarine has grown greater and ever greater, until from a craft
hardly larger than a power pleasure boat there has been evolved a truly
wonderful undersea vessel of magnificent proportions.

=Uncle Sam’s Latest Submarines.=—The result of this marvelous
development is that the latest of Uncle Sam’s submarines are of the
1200 and 1500 tons _displacement_ type and they have a speed of 21
knots on the surface.

These giant submarines have a cruising radius of about 4,000 miles and
are fitted with every instrument, device, apparatus and machine that
human ingenuity can think of, or at least that has been invented, which
goes to make for their operating and fighting qualities and for the
safety and comfort of their crews.

From this you will see that since the year of 1900 the size of these
craft has been increased about four times, their speed doubled, and
their efficiency raised to half again as much. Based on the rapid
strides that have been made since the war has been going on, it does
not take any great foresight to predict that in the near future, if the
U-boat blockade is not broken, submarines of upwards of 500 feet in
length and 10,000 tons’ displacement will form the merchant fleet of
the United States.

=The Great Blockades of the Warring Nations.=—The great blockades by
which the Allies have bottled up the German Empire by their superior
naval forces, and by which Germany is trying to shut off the trading of
other countries with the Allies by her U-boat warfare, have prevented
either side from scoring a victory.

But with Germany’s usual dogged determination for overcoming the
difficulties that beset her, she built a submarine which could travel
without a _convoy_, that is, without any base-ship to go along with her
to provision and supply her needs, for 5,000 miles at least.

This giant submarine carried a cargo worth a million dollars or more,
sunk out of sight as she left her home port, slipped underneath the
grim warships of the Allies which menaced German shipping, and in this
way ran the blockade.

Then one fine day there bobbed up in American waters near Chesapeake
Bay a monster merchant submarine—the largest underwater craft ever
built and the first of her kind ever seen. She was in very truth a nine
days’ wonder.

=The First of the Merchant Submarines.=—The _Deutschland_, as she was
named, was a marvel of engineering skill, and she was hailed as the
first of a great fleet of merchant submarines which was to break the
Allies’ blockade.

Starting from Bremen, Germany, and traveling underwater through the
English Channel for a distance of 90 miles without even once coming to
the surface, she made the entire voyage without mishap and docked at
Baltimore just 16 days later.

When you think of how carefully she had to be handled and how
cautiously she had to proceed so that she might escape destruction at
the hands of her surface enemies, you must admit that she made the run
in really remarkable time.

=Some Facts About the Deutschland.=—This great merchant submarine is
315 feet long, 30 feet through the beam, and _draws_[40] 17 feet of
water. She is, therefore, as large as many of our coastwise steamers,
so that she is something more than a mere underwater boat—indeed, she
is a veritable submarine _ship_.

Her hull is shaped more nearly like that of a real ship than any
submarine craft that was ever built before her, as Fig. 69 shows; but
she has a conning tower, periscopes and wireless masts like any of the
other of the tribe of submarines.


[Illustration: _Courtesy of Scientific American_


Her wireless aerial is held in place between two steel masts, each
of which is 50 feet high and both of which can be folded down on the
deck. The mast on her for’ard deck is fitted with a _crow’s nest_ for a
_lookout_, as though she were a real ship.

_Her Captain and His Crew._—The inside of her hull is very much like
an ordinary merchantman. For’ard are large and comfortable quarters
for the officers, of whom there are nine, including Captain Koenig—a
man you can’t help but admire. Abaft the ship are the quarters for the
crew, and both fore and aft in her hold are compartments for the cargo
she carries.

_Her Valuable Cargo._—In making her first trip over from Bremen her
cargo consisted of dyestuffs, medicines, _synthetic stones_[41] and
other merchandise which took up small storage room and yet which was
very valuable.

These she unloaded in Baltimore, and her return cargo was made up of
crude rubber, tin, and nickel—materials much needed by the German
Government for purposes of warfare.

She also served the very useful purpose of a _packet_, for by means of
her Captain Koenig was able to hand personally to Count von Bernstorff,
the German Ambassador to the United States at that time, important
instructions which would otherwise have been hard to get through.

Again, what was of even greater urgency was that the Count was able
to get rid of certain documents which would have made matters quite
uncomfortable for him if they had been found in his possession some
months later when the break came between the United States and Germany.

_Her Great Engines._—The _Deutschland_ is driven by two 600-horsepower
Diesel engines, each of which has four cylinders. She is able to make a
speed of 14 knots on the surface, but when submerged her speed is only
about half as much.

She is supplied with enough liquid fuel and solid foods to enable her
to cruise for 5,000 miles without making port.

Such is the _Deutschland_, and to her belongs the distinction of being
the first underwater merchantman. Under the skilful command of her
captain, she served her country nobly and well for the purpose for
which she was built.

=How the United States Can Break the Blockade.=—Right now the United
States and the Allies have to face the same gigantic problem that was
forced upon Germany at the beginning of the war, and that is to break
the enemy’s blockade.

The scheme of keeping the sea-roads clear for shipping by destroying
the U-boats has proved a slow and hard process, and so new plans have
been mapped out by our naval engineers and others with which to defeat
the blockade.

_The Wooden Ship Idea._—The first plan, and one which is being carried
out with great energy, is the building of hundreds of little wooden
ships, each of which is 25 feet shorter than the _Deutschland_ and has
a cargo carrying capacity of 3,500 tons, and a speed of 4 knots less
than the surface speed of the great German submarine.

The main idea seems to be to turn these little boats out fast enough so
that the number the U-boats sink will be so small that the loss will
not be felt. The glaring fault of this idea is that while the U-boats
are sinking 500,000 tons of shipping a month, American ship-builders
can build only 200,000 tons a month, and this is figuring it out with a
liberal margin.

While these small wooden craft of the vintage of 1850 would relieve the
stress that is now felt in shipping circles they would not by any means
remove it.

_The Submarine Plan._—Simon Lake, the inventor of the submersible, has
enlarged upon the German plan, and his plan is one which our Government
ought to carry out, because, in the humble opinion of the writer, it is
the only feasible one thus far advanced.

Mr. Lake has organized a company to build a fleet of undersea
merchantmen, each boat of which will be ten times as large as the
_Deutschland_ and can carry a cargo of 7,500 tons. Mr. Lake says that
with the co-operation of the Government he can build 100 of these giant
craft in the first year, and that at the end of three years he can have
a fleet of 500 of them built and in service. That is to say, in this
short time he can have 4,000,000 tons of cargo sailing the seas with
absolute safety.

This plan of the great submarine builder is the key which will unlock
the horns of our dilemma. The only drawback seems to be the ability
of a company to turn out so complex a mechanism as the submarine,
and of such an enormous size, fast enough to make up for the rapidly
disappearing tonnage of the Allies.

In the meantime the submarine chasers and the wooden and steel ships
that are now being built may help to some extent to take care of our
shipping until the great commercial submarines of Lake can be built and
put into the trans-Atlantic service.

=When Submarine Meets Submarine.=—When Greek meets Greek then comes the
tug of war, so the old saw goes, and it is just as true that the way to
break the blockade of the U-boats is to pit the cunning of submarines
against them.

With all our shipping going by the undersea route, the U-boats will
lose their sting, the blockade will be broken, the power of the Allies
will outweigh that of Germany, and the war will speedily come to an end.

And may that time come soon!



  Air chasers, submarine, 195

  Air, compressed, 67

  Air compressor pumps, 67

  Air control mechanism of a model submarine, 32, 42

  Aircraft attacks, 177

  Air flashes, 67

  Airplane, the, 195
    versus submarine, 139

  Air pressure required to drive torpedo, 101

  Airship, the, 195

  Air tanks of a torpedo, 108

  Action, the model torpedo in, 96

  Aerial, wireless, 55

  Allies’ blockade, 200

  Allies, the, 1, 176, 185, 200

  Ananias club, 139

  Anchor, mushroom, 69

  Angle, definition of, 59

  Angle indicator, 60

  Armament, definition of, 117

  Arming merchantmen with guns, 187

  Artemus Ward, 23

  Attacks, how a submarine, 171

  Automatic gyro control, 101
    pendulum control, 102

  Automobile torpedo, 92, 115

  Auxiliary, definition of, 171

  Awash condition, 62

  Awash, definition of, 23

  Baby Holland, 199

  Back pressure, 68

  Balance chamber, 101

  Ballast pumps, what they do, 66

  Ballast tank of a model submarine, 28

  Ballasting the model submarine, 40

  Balloon, dirigible, 189

  Base ship, what it is for, 161

  Bell for submarine signaling, 151

  Bell or violin signaling system, 151

  Blackheads, 92

  Blind fish of Mammoth Cave, 58

  Blockade, how the U. S. can break the U-boat, 204
    the Allies’, 200

  Blockade, the submarine plan to break the U-boat, 205
    the wooden ship idea, 204
    a way to lift the U-boat, 195
    by U-boats, 200

  Blockades of the warring nations, great, 200

  Body of a model torpedo, 92

  Bomb, clock-work of a submarine, 10
    submarine, 9

  Bomb idea, the, 116
    the old, 91

  Book of wireless, 149

  Bores of Allies’ submarine guns, 120

  Boy of the Prehistoric Age, 3

  Boy, the second submarine, 1
    when he learned to swim, 3

  Bushnell’s submarine, 7

  Bushnell, submarine boat inventor, 8

  Bulkhead door, electrically operated, 59

  Bulkhead in model submarine, putting in, 34

  Buoyancy, 63
    experiment in, 67
    natural, 67
    reserve, 63, 67

  Buoyancy tanks, what they are for, 66

  Caliber, definition of, 188

  Campbell and Ash, English submarine boat inventors, 14

  Carburetor, for gasoline engine, 76
    what it does, 78

  Centennial Exposition, 13

  Central Powers of Europe, 1

  Central Powers, the, 176

  Chaser, how it chases a submarine, 192
    shooting the guns of the, 193

  Chasers, submarines, 116

  Chasers for submarines, air, 195

  Cipher code, definition of, 166

  Clock-work of a submarine bomb, 10

  Collapsible boat, 178

  Colored light signaling system, 146

  Commanding officer, the, 164

  Commutator of model electric motor, 39

  Compass, 55

  Compass courses, 167

  Compass, gyroscopic, 58

  Compartment, diving control, 60
    mine, 68
    torpedo, 68

  Compartments, watertight, 53

  Compressed air, 67

  Compressed air action gun, 119

  Compressed air for driving engine, 105

  Compressed air tanks, 100

  Compression stroke of engine, 78

  Conditions of the submarine, four, 62

  Conductivity system, how it works, 155
    parts of, 155

  Conductivity system of signaling, 154

  Connecting up the power plant circuit of the model submarine, 42

  Conning tower of a model submarine, 42

  Conning tower, outside of the, 54
    peep into the, 56

  Contact mines, 122

  Contact mine, how it works, 123

  Contraband, definition of, 178

  Course of a torpedo, 110

  Crews, hard to sign, when, 160

  Crew of a submarine, 69

  Davis, torpedo inventor, 111

  Deck of a model submarine, 28, 35

  Defense, the submarine flotilla as a means of, 173

  Depth indicator, 60

  Depth meter, 59

  Depuy de Lôme, French submarine inventor, 16

  Destroyers, submarine, 177

  Destroying mother ships, 188

  Detonating or firing mechanism, 98

  _Deutschland_, cruising radius of the, 204
    her great engines, 204
    her valuable cargo, 203
    some facts about the, 201
    the captain and crew of the, 203
    the largest submarine, 201

  Diesel engine, 80
    how it works, 80

  Diesel, German gas engine inventor, 80

  Dirigible balloon, 189

  Dives, how a submarine, 64, 68

  Dive is made, why a shallow, 65

  Dive, time it takes for submarine to, 66

  Diving control compartment, 60

  Diving rudder, 53, 59
    of a model torpedo, 95

  Diving rudders, fore, 64

  Diving wheel, 60

  Doyle, inventor of Sherlock Holmes, 130

  Draw, definition of, 201

  Dry cells for model electric motor, 35

  Dry cells, where to buy, 35

  Dummy heads, 167

  Dynamo, definition of, 85, 86

  Dynamo motor and storage battery system, 85

  _Eagle_, first warship to be attacked by a submarine, 9

  Ears of a submarine, 143

  Electric controlled mine, 124

  Electric motor, 34, 85
    commutator of an, 39
    discovery of the, 14
    where to buy an, 35

  Electric motor current of a model submarine, 43

  Electric motor for model submarine, 35

  Electric motors, 14, 56

  Electric power plant, why it is needed, 85

  Electric submarine, invention of the, 14

  Electric switch of model submarine, 36

  Electrically controlled mines, 122

  Electricity for the submarine, 15

  Enemy ships, gauging the distance of, 136

  Enemy of the submarine, a new, 139

  Engines, 73

  _Engine Building for Boys_, 74

  Engine, carburetor for gasoline, 76

  Engines, compressed air for driving, 105

  Engine, Diesel, 80
    that drives the torpedo, the, 104
    faults of the steam, 74
    four cycle, 75
    gasoline, 75

  Engines, horse power of, 83
    last word in submarine, 80

  Engine works, how the Diesel, 80
    how a gasoline, 75

  Exhaust stroke, 78

  Experiment in buoyancy, 67

  Explosive, amount needed for a torpedo, 98
    high powered, 97

  Explosive compounds, 98

  Eye, the first submarine, 130

  Eye of submarine, 55
    wonderful, 129

  Firing mechanism, 98

  First Holland submarine, 5

  First submarine boat, 5

  Fish, air bladder of, 2
    the first submarine, 1

  Fish of Mammoth Cave, blind, 58

  Floating dock, 162

  Flashlight system of signaling, 146

  _Fly, How to_, 196

  Freedom of the seas, 185

  Fuel mixture, 76

  Fulton’s experiments on the Seine River, 10

  Fulton’s first steam boat, 12

  Fulton’s first submarine, 10

  Fulton’s _Nautilus_, 10

  Fulton plans to rescue Napoleon, 12

  Fulton, submarine boat inventor, Robert, 10

  Galley of a submarine, 70

  Game, naval war, 96

  Garrett, English submarine boat inventor, 12

  Garrett’s steam propelled submarine, 12

  Gas and electric power combined for the submarine, 15

  Gas engine, 34
    for the submarine, 15

  Gas engines, two cycle, 82

  Gasoline, 79

  Gasoline engine, 75
    how it works, 75

  Gauging the distance of enemy ships, 136

  Granddaddy of the modern submarine, 6

  German Empire, the, 200

  German policy, 115

  Grecian galleys of old, 5

  Greek meets Greek, when, 206

  Gun, compressed air action, 119
    the Lewis machine, 196
    need of a quick-action, 117
    spring action, 118

  Guncotton, 97

  Guns, arming merchantmen with, 187

  Guns, arming the submarine with, 116

  Guns, bores of Allies’ submarine, 120
    rapid-fire machine, 115

  Guns of the chaser, shooting the, 193

  Gyro control, automatic, 101

  Gyroscope, action of a, 102
    compass, 58
    toy, 102

  Heart of a submarine, 73

  High tension current, 79

  High tension magnets, 76

  Holland and Lake combined type of boats, 17

  Holland submarine, 51 the first, 5

  Holland, submarine inventor, 16
    baby, 199

  Horse power of submarine engines, 83

  Horsman Co., toy dealers, 102

  _How to Fly_, 196

  How the hull is made, 52

  How to make and work a model submarine, 23

  How a real submarine is made and works, 51

  How to work your model submarine, 47

  Hull, definition, 51
    how it is made, 52
    inside the, 55
    of a model submarine, 24

  Hydroplanes of a submarine, 64

  Hydrostatic control, 103

  Ichthyoid form, 2

  Inside the hull, 55

  Installing the motor in model submarine, 39

  Integral, definition of, 164

  _Inventing for Boys_, 58

  Inventors of the submarine, 4

  Inventors of submarine,
    American, 7

  Knot, definition of, 13

  Koenig, captain of the _Deutschland_, 203

  Krupp, German gun makers, 118

  Lake, his plan for undersea merchantmen, 205
    submarine inventor, 16
    submersible, 51
    submersible boat, 16

  Latent heat, 106

  Latitude, how found, 167

  Laying mine fields in harbors, 187

  Lee, operator of Bushnell’s submarine, 10

  Lenticular, definition of, 132

  Lewis machine gun, 196

  Lewis, machine gun inventor, 196

  Lieutenants, how to pronounce, 165

  Light condition, 61

  Listening in, 150

  Log distances, 167

  Longitude, how found, 167

  Lupius, Austrian torpedo inventor, 92

  _Magic of Science_, a book, 133

  Magneto electro machine, 79

  Magneto, high tension, 76

  Magnetic lines of force, stray, 58

  Main parts of a submarine, 57

  _Maine_ was sunk, way the, 122

  Making the superstructure of a model submarine, 41

  Mammoth Cave, blind fish of, 58

  Maneuver, definition of, 166

  _Mayflower_, landing of the, 5

  Merchant submarine, the first, 201

  Merchantman, how a submarine attacks a, 177

  Mercuric fulminate, 99

  Millimeter, definition of, 119

  Mine compartment, 68

  Mine, electric controlled, 124

  Mine fields in harbors, laying, 187

  Mine layer, 69, 120

  Mine works, how a contact, 123

  Mines, how they are made, 122
    how a submarine lays, 120
    kinds of submarine, 121
    submarine, 115

  Model submarine, air control mechanism of a, 32
    ballast tank for a, 28
    ballasting the, 40
    conning tower of a, 43
    how to make and work, 23
    how to work your, 47
    hull of a, 24
    installing motor in, 39
    painting your, 47
    parts of a, 24
    periscope of, 48
    power plant in, 34
    power plant of a, 24
    propeller for a, 45
    propeller-shaft for, 39
    pusher control for, 36
    rudder for the, 45
    superstructure of a, 41
    torpedo, how to make a, 92

  Model torpedo, in action, the, 96
    body of a, 92
    motor for a, 95
    rudders of a, 93

  Mother ships, destroying, 188

  Mother ship, what it is, 162

  Motor for a model torpedo, 95

  Motor, rubber strand, 95

  Munitions, definition of, 115

  Mushroom anchor, 69

  Napoleon, attempts to rescue with a submarine, 12

  Nautical mile, 13

  _Nautilus_, Fulton’s first submarine, 10

  Naval war game, 96

  Navigating room, 60

  Neutral, definition of, 176

  Nordenfelt, Swedish submarine boat inventor, 13

  Nose and tail blocks of a model submarine, 26

  Offense, the submarine flotilla as a means of, 174

  Painting your model submarine, 47

  Paleozoic era, submarine of, 2

  Parts of a model submarine, 24

  Parts of a submarine, 52

  Pendulum control, automatic, 104

  Percussion caps, 100

  Permutation in signaling, 145

  Periscope, 55, 129
    complete view, 137
    the first, 130
    how it got its name, 129
    how it is made, 134
    how to make a simple, 130
    how it works, 131

  Periscope, latest type of, 136
    limited use of the, 138
    of the model submarine, 48
    the modern, 132

  Personnel of a submarine crew, 159

  Pilgrims on Plymouth Rock, 5

  Pipes for model submarine, 32

  Pipes, where to buy them, 32

  Pirate, submarine, 4

  Plans for a model submarine, 23

  Plantéol, inventor of the storage battery, 14

  Power plant, 33

  Power plant circuit of model submarine, 44

  Power plant in model submarine, 34

  Power plant of a model submarine, 24, 32
    how it is hooked up, 36

  Power plant is needed, why an electric, 85

  Power stroke of engine, 77, 78

  Power unit, 75

  Prehistoric boy, 2

  Prime mover, 75

  Prisms, reflecting, 133

  Projectile, how a bow trajectory affects a, 194

  Projectile, how a flat trajectory affects a, 194

  Propeller for a model submarine, 45

  Propeller-shaft of a model submarine, 39

  Propeller-shaft of a torpedo, 106

  Propellers of a torpedo, the, 106

  Pterodactyl, largest flying creature, the, 3

  Pumps, air-compressor, 67

  Pusher control of a model submarine, 36

  Quadrant, 60

  Quick-action guns, 117

  Raw recruits, breaking in, 166

  Reducing valve, 101

  Reflecting prisms, 133

  Reserve buoyancy, 63, 67

  Rise of the submarine, 172

  Rookies, what they are, 164

  Roosevelt, inventor of the Ananias Club, 139

  Rubber strand motor, 95

  Rudder, diving, 59
    for the model submarine, 45

  Rudders, fore diving, 64
    diving, 53
    of a model torpedo, 93

  Rudders, of the torpedo, steering and diving, 107

  Scout, the submarine as a, 175

  Sea anchor, 69

  Searchlight signal system, 146

  Semaphore for signaling, 144

  Servo-motor, the, 103

  Setting ballast tank in the hull of model submarine, 34

  Shape of a submarine, 52

  Shipping, definition of, 185
    tonnage per month, 205

  Ships, gauging the distance of enemy, 136

  _Shooting for Boys_, 193

  Shooting, the guns of the chaser, 193
    the torpedo, 91
    a torpedo at a ship, 107

  Signaling with colored lights, 146
    with the flashlight system, 146
    permutation in, 145
    with the searchlight system, 146
    semaphore for, 144
    by underwater “wireless,” 154
    wigwag, 144

  Signaling, with the wireless telegraph system, 147

  Signaling systems, kinds of, 144
    underwater, 151

  Skins, inner and outer, 53

  Skin of a model submarine, 27

  Solder, how to, 28

  Soldering fluid, 28

  Spark plug, 79

  Specifications for a model submarine, 23

  Spirit level, 60

  Spring action gun, 118

  Squadron, definition of, 172

  Steamboat, Fulton’s first, 12

  Steam engine, faults of, 74

  Steam propelled submarine, first, 12

  Steering rudder of a model torpedo, 95

  Steering rudders, 53

  Steering wheel, 55

  Storage batteries, 14, 34, 74, 85, 86

  Storage battery and dynamo motor system, 85

  Storage battery, inventor of the, 74

  Submarine air chasers, 195

  Submarine, air control mechanism of a, 32
    ballast tank for a, 28

  Submarine, ballasting the, 40
    as a blockader, the, 176

  Submarine bases, destroying, 126

  Submarine bell, 151

  Submarine boat, the first, 5
    what it is, 16

  Submarine bomb, 9

  Submarine chaser, 80-foot, 189
    110-foot, 189

  Submarine chasers, 116, 177
    kinds of, 188

  Submarine in Chesapeake Bay, a giant, 200
    clock-work of a, 10
    complement of a, 164
    conning tower of a model, 42
    construction of Bushnell’s, 8

  Submarine craft, early conditions on, 159
    crew of a, 69
    crew, personnel of, 159
    cruising radius of a, 162

  Submarine destroyers, 177
    the _Deutschland_, 201
    development of the, 4

  Submarine duty, how men are trained for, 164
    electric power for the, 15

  Submarine engines, last word in, 80

  Submarine eye, the first, 130
    the first merchant, 201
    first steam propelled, 12
    the first torpedo fired by a, 9
    first torpedo tube, 13

  Submarine flotilla as a means of defense, the, 173

  Submarine flotilla as a means of offense, 174
    four states of the, 61
    Fulton’s _Nautilus_, 10
    Fulton’s turned down, 10

  Submarine galley, 70
    gas power for the, 15
    a giant, 200
    granddaddy of the modern, 6

  Submarine, with guns, arming the, 116
    Bushnell’s, 7
    Bushnell’s second, 8
    guns, bores of Allies’, 120
    heart of a, 73
    Holland, 51
    Holland type of, 16
    how it attacks, 171
    how it attacks a merchantman, 177
    how it came to be, 1
    how a chaser chases a, 192
    how it dives, 64, 68
    how to make and work a model, 23
    how it is submerged, 65
    how to work your model, 47
    hull of a model, 24
    hydroplanes of a, 64
    installing motor in model, 39
    invention of the electric, 14
    invention of the screw-driven, 9
    inventors of the, 4
    Lake type of, 16
    the largest, 201

  Submarine lays mines, how a, 120

  Submarine is made and works, how a real, 51
    main parts of a, 57
    marvelous tongue and ears of the, 143

  Submarine meets submarine, when, 206

  Submarine mines, 115

  Submarine mines, kinds of, 120
    a modern, 18
    new enemy of the, 139
    Nordenfelt, 13
    painting your model, 47

  Submarine of the Paleozoic era, parts of, 52
    parts of a model, 24
    periscope of the model, 48

  Submarine pirate, 4
    power plant of a model, 24
    power plant in model, 34
    propeller for a model, 45
    propeller-shaft for a model, 39
    pusher control for a model, 36
    to rescue Napoleon, attempts with a, 12
    rise of the, 172
    Robert Fulton’s first, 10
    rudder for the model, 45
    in the Russo-Japanese War, 172
    schemes for outwitting the, 186
    as a scout, the, 175
    shape of a, 52
    in the Spanish-American War, 172
    superstructure of a model, 41
    time it takes to dive, 66
    torpedo, how to make a model, 92
    uses of the, 170
    Van Drebel’s, 5
    what it is, 1
    wonderful eye of, 129

  Submarine works with the fleet, how the, 173

  Submarines, airplanes, a new enemy of, 139

  Submarines, American inventors of, 7
    cruising radius of Uncle Sam’s, 199
    the first, 1

  Submarines for the trans-Atlantic service, 206
    types of, 16
    your Uncle Sammy’s latest, 199
    when they attack in pairs, 179

  Submerged condition, 62

  Submerge, definition of, 51
    how the boat is kept, 65

  Submersible boat, Lake, 16
    what it is, 16

  Submersible, Lake, 51

  Suction stroke of engine, 77

  Superstructure of a model submarine, 41

  Superstructure, what it is, 53

  Synthetic stones, definition of, 203

  Tactician, definition of, 164

  Targets, floating, 167

  Telescope, how it is made, 132
    how it is made and works, 133

  Tell-tale, 59

  Timer for gasoline engines, 79

  Time fuse, 112

  TNT for torpedoes, 97

  Tongue of a submarine, 143

  Torpedo in action, the model, 96

  Torpedo, air pressure required to drive, 101

  Torpedo air tanks, 108
    automobile, 92, 115
    body of the, 100
    body of a model, 92

  Torpedo with a cannon in it, 111

  Torpedo compartment, 68
    course of a, 110

  Torpedo director, a, 100
    engine that drives the, 104

  Torpedo fired by a submarine, the first, 9
    first submarine, 92
    how it is aimed, 109
    how to make a model submarine, 92
    high powered explosive for the, 97
    how a real one is made, 108
    how it is shot at a ship, 107
    is made, how a real, 97
    making and shooting the, 91
    motor for a model, 95

  Torpedo practice, 167
    propellers of a, 106

  Torpedo, rudders of a model, 93
    steering and diving rudders for a, 107

  Torpedo, warhead of, 93, 97
    weight of, 68

  Torpedo tube, the, 108
    submarine, first, 13

  Torpedoes, TNT for, 97

  Totally submerged condition, 62

  Trajectory, bow, 194

  Trajectory, flat, 191

  Trans-Atlantic submarine service, 206

  Trimming tanks, 58

  Trimming tanks are used, why, 62

  Tuning in, 150

  Two-cycle gas engines, 82

  U-boat blockade, 200
    a way to lift the, 195

  U-boat, German captain of a, 109

  U-boat menace, 195

  U-boat, what it is, 1

  U-boats, German, 185
    plans for destroying the, 187

  Uncle Sammy’s latest submarines, 199

  Uncle Sammy, your, 196

  Underwater signaling system, 151

  Valve, reducing, 101

  Van Drebel, submarine boat inventor, 5

  Van Drebel’s experiments on the Thames River, 6

  Van Drebel’s submarine, 5

  Violin transmitter, 152

  Violin or bell signaling system, 51

  Von Bernstorff, Ex-German Ambassador to the United States, 203

  Warhead of a torpedo, 93, 97

  Warplane, 189

  Water pressure control, 103

  War time conditions, 167

  War between U. S. and Spain, 122

  Watertight compartments, 55

  Watertight doors, 56

  Whitehead, American torpedo inventor, 92

  Wigwag signaling, 144

  Windjammers of old, 70

  Wireless aerial, 55

  Wireless, how it works, 149

  Wireless telegraph system, 147

  Wireless system, parts of, 147

  Wireless in war time, 168

  Work your model submarine, how to, 47

  Worm gears, 56

  Zédé, Gustave, French submarine inventor, 16


[1] _Central Powers_: Germany, Austria, and Bulgaria.

[2] _Allies_: Governments united by a treaty or having common
interests. England, France, Belgium, Russia, Italy, the United States,
and Japan are called the _Allies_.

[3] _U-Boat_: So called because it is an undersea boat, or
_Unterseeboote_, as the Germans call their submarines.

[4] _Paleozoic._—The next to the lowest geological series of strata.

[5] The _Pterodactyl_ was one of these and it was the largest living
thing that ever flew. It is pronounced _Ter-o-dak´-til_.

[6] A _knot_ is the speed of a boat when she is making 1 _nautical_
mile in 1 hour. A nautical mile is 6,080 feet.

[7] The design, construction and operation of submarine torpedoes will
be found in Chapter V.

[8] The storage battery was invented by Gaston Planté in 1860. The
electric motor was discovered in 1876, by whom nobody knows.

[9] These pipes can be bought cut to length and threaded to suit of The
Chicago Model Works, 166 West Madison Street, Chicago, Ills., or of
Luther H. Wightman, 132 Milk Street, Boston, Mass.

[10] The L. E. Knott Apparatus Company, of Boston, Mass., sell a
_standard motor_, as they call it in their catalogue, for $3.75. It
weighs 1½ pounds and takes up a space of about 3½ inches square.
Powerful little motors can be bought at almost any electrical supply
house, and you can use one of these by building up the base.

[11] Cells of this kind that measure 2 x 2½ x 6 inches on the sides can
be bought of the Manhattan Electrical Supply Company, of 17 Park Place,
New York City.

[12] A machinist’s saw for sawing metal.

[13] The pulley can be bought of dealers in model makers supplies. See
footnote on page 32.

[14] You can certainly get it of the F. W. Devoe and C. T. Raynolds
Company, 101 Fulton Street, New York City.

[15] The top of the conning tower is called the bridge.

[16] The hull is the body or shell of a boat or ship.

[17] For a description of the gyroscopic compass, see _Inventing for
Boys_, by the present author and published by the Frederick A. Stokes
Company, New York.

[18] Any figure formed by two straight lines which meet is an angle,
also the space between them.

[19] For a simple theory of how the steam engine works, see _Engine
Building for Boys_, by the present author and published by Small,
Maynard & Co., Boston.

[20] Any kind of machine which develops its power at first hand is a
_prime mover_, as, for instance, the water wheel, steam engine, and
gas engine. An electric motor energized by a storage battery, or a
compressed air motor are only _subsidiary movers_.

[21] A _dynamo_ is an electric machine, which generates a _direct
current_ of electricity, like a battery.

[22] It can be bought of the E. I. Horsman Co., Toy Dealers, Union
Square, New York.

[23] The guns and other munitions on a boat are called her _armament_.

[24] The _millimeter_ is the 1-1000 part of a _meter_. The meter is the
fundamental unit of length used in the metric system of measurement. It
is 39.37 inches.

[25] Lenticular (pronounced len-tik´-u-lar) means having lenses.

[26] Telescopes and their construction are fully explained in _The
Magic of Science_, by the present author, and published by Fleming H.
Revell Co., New York.

[27] 360 degrees = a complete circle.

[28] For a complete description of how to make and use wireless
apparatus, and how it works, see _The Book of Wireless_, by the present
author, and published by D. Appleton & Co., New York.

[29] A _floating dock_ is built with a water compartment on each side
and a platform on the bottom, thus leaving a large open space in
between to hold a submarine or other vessel. By partly filling the
compartments with water the platform sinks into the water deep enough
so that the vessel can pass over and on top of it; then by pumping
the water out of the compartments the floating dock is raised and the
platform with the vessel on it is lifted out of the water where she can
be examined and repaired if necessary.

[30] _Integral_ means a part of a whole thing which is needed to make
it complete.

[31] A _cipher code_ is one in which the message is telegraphed in the
Morse alphabet of dots and dashes as usual, but the words which form
the message are given other meanings which have been previously agreed
upon, and this prevents the enemy from knowing what is sent.

[32] The word _auxiliary_ in this sense means other smaller and less
important craft which give aid to and supports the larger and more
powerful ships of the fleet.

[33] A squadron is one of the divisions of a fleet.

[34] A country that neither helps nor hinders the countries that are at
war is said to be _neutral_.

[35] July, 1917.

[36] A boat’s capacity for cargo.

[37] The _caliber_ of a gun is the _gage_, or diameter of the _bore_
of its barrel. Thus a gun of 3-inch caliber means that the bore is 3
inches in diameter; a gun that has a caliber of 45 _centimeters_ means
that its bore is 45 centimeters across. A centimeter is 1/100 of a
_meter_ and a meter is 39.37 inches.

[38] For a full description of the trajectory of bullets, see _Shooting
for Boys_, by the present authors, and published by Moffat, Yard & Co.,
New York

[39] A full description of the Lewis machine gun for airplane work will
be found in _How to Fly_ by the present author and published by D.
Appleton and Co., of New York.

[40] This means she sinks into the water 17 feet.

[41] These are real rubies, sapphires, and other gems made of chemicals
in an oxyhydrogen furnace.

       *       *       *       *       *

Transcriber’s Notes:

Obvious punctuation errors repaired.

Page 29, “to-together” changed to “together” (bring the ends together)


Page 115, “no” changed to “not” (not so, for there)

Page 122, “betwen” changed to “between” (war between the United)

Page 124, “torquoise” changed to “turquoise” (the turquoise seas)

Page 136, “Guaging” changed to “Gauging” (Gauging the Distance of)

Page 139, “runing” changed to “running” (boat is running light)

Page 155, the word of “telegraph” was split over two lines and the
first half was not italicized but the rest of the phrase for “telegraph
key” was. This was edited to italicize the whole phrase.

Page 218, “Tactitian” changed to “Tactician” (Tactician, definition)

Index, all items out of alphabetical sequence were rearranged.

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