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 THE SPERRY GYRO-COMPASS,
 BY
 THE SPERRY GYROSCOPE CO.


 [Illustration]


 _Copyright,_ 1920
 THE SPERRY GYROSCOPE COMPANY
 BROOKLYN, N. Y., U. S. A.

 DESIGNED, ENGRAVED
 AND PRINTED BY

 [Illustration: ROBERT L. STILLSON
 COMPANY NEW YORK]


 THE

 SPERRY

 GYRO-COMPASS


 [Illustration]


 THE SPERRY GYROSCOPE CO.

 MAIN OFFICE AND FACTORY

 MANHATTAN BRIDGE PLAZA.
 BROOKLYN, N.Y.

[Illustration: Man’s first venture in shipbuilding was the Raft.]

[Illustration]


THE SPERRY GYROSCOPE COMPANY

 _Boston, Mass._
 60 VIRGINIA STREET

 _Great Lakes District_
 828 GUARDIAN BUILDING
 Cleveland, Ohio

 _San Francisco, Cal._
 52 DAVIS STREET

_Main European Office_: THE SPERRY GYROSCOPE COMPANY, Ltd., 15 Victoria
Street, London, S. W. 1

—REPRESENTATIVES—

 _France_

 COMTE A. DeCHAMBURE
 37, Rue Bergere
 Paris

 GEORGES BREITTMAYER
 20, Rue Taitbout
 Paris

 F. J. DELVES
 20, Rue Taitbout
 Paris

 _Spain_

 F. WEYDMANN
 Victoria 2
 Madrid

 _Holland_

 TECHNISCH BUREAU VAN LEENT
 Nassaukade 17
 Ryswyk

 _Italy_

 F. P. CAMPERIO
 Via Bagutta 24
 Milan

 _Sweden_

 GRAHAM BROS.
 Stockholm

 _Denmark_

 C. KNUDSEN
 11 Kobmagagade
 Copenhagen

 _Norway_

 OTTO PLATOU
 Skovveien 39
 Christiania

 _Japan_

 MITSUI & CO., LTD.
 Tokyo

 MITSUBISHI ZOSEN KAISHA, LTD.
 Tokyo
 (For Ship Stabilizer)

 _Chili, Peru & Bolivia_

 WESSEL DUVAL & CO.
 25 Broad Street
 New York

[Illustration: An inflated ox-skin Balsa of earliest times.]


 THE
 SPERRY GYROSCOPE
 COMPANY

[Illustration]

 _Manufacturers of_

 GYRO-COMPASSES      GYRO SHIP STABILIZERS
 GUN-FIRE CONTROL APPARATUS      NAVIGATIONAL INSTRUMENTS
 NAVAL AND COMMERCIAL SEARCHLIGHTS

[Illustration: The ancient Egyptians built boats of rushes.]




_Putting the Earth to Work_


When the earth was thrown off from the sun and commenced rotating about
its own axis, there was developed a force generated by the earth’s
rotation. For countless centuries this force has been at work, but no
one has ever been able to harness it to serve the purposes of man. But
now, through the efforts of Foucault, Hopkins, Sperry, and other noted
scientists, this force has been put to work. It serves to direct a
thousand ships in their courses.

Of course, this is not the only force which has been used to guide
ships. Since 1297 A.D. mariners have used magnetic attraction as the
force by which to guide their vessels. For centuries seafaring men
sailed only in wooden ships, and were therefore satisfied with the
magnetic compass. Then came steam and steel. Navigation then instead of
being a hit or miss game of chance became the exact art of directing a
ship by the shortest possible course in the quickest possible time.

Now that ships cost millions of dollars to build and thousands of
dollars per day to operate, time has become the most essential element
in navigation. The development of ships from the sailing vessel to
the ocean greyhound has been one of the marvels of modern times.
But the development of the magnetic compass has not kept pace with
the development of the ships which rely upon it. Many of the great
trans-Atlantic liners are guided by practically the same type of
compass as that which Columbus used on the _Santa Maria_. The compass
on the wooden _Santa Maria_ pointed to magnetic north with a fair
degree of accuracy, but the compass on the steel greyhounds must
contend with many distractions.

For years magnetic compass designers spent their efforts to produce
compensating devices that would annul the effects of all external
influences, so that the magnetic compass would be free to indicate only
the direction of the earth’s magnetic lines. Very little has been done
to improve the compass itself—it still depends upon the attraction of
the Magnetic North Pole. The Sperry Gyro-Compass differs in principle
from any other compass. It is not magnetic. It derives its directive
force, not from magnetic attraction, but from the earth’s rotation.

[Illustration: Bearing Repeater on Upper Bridge.]

[Illustration: The Vikings crossed the Atlantic in open ships.]

There is certainly a crying need for this new type of compass. A ship
now-a-days costs millions of dollars and carries cargoes usually equal
in value to that of the ship. It has been estimated that inaccuracies
in navigation attending the use of the magnetic compass cause a yearly
loss of ships to the value of $70,000,000. No estimate can possibly be
made on the value of lives lost on these ships.

Millions of dollars are spent each year on charts, lighthouses, buoys,
geodetic and hydrographic surveys, and on compilation of notices to
mariners. Notwithstanding all of these, ships must ultimately depend
upon their compasses for their safety and efficiency of navigation.

Inaccuracies in navigation can be eliminated by the use of a reliable
compass. The Sperry Gyro-Compass puts the earth to work. It utilizes a
force which is as unvarying as the law of gravity, a force that cannot
be interfered with by any other influence.


How the Earth’s Rotation Is Utilized

Any wheel rotating at a high speed about its own axis, and free to
place itself in any plane, is called a _Gyroscope_. The _Gyroscope_ is
the instrument which utilizes the earth’s rotation as a force to direct
the course of ships.

Suppose you were to place such a small wheel supported by its axis upon
a larger wheel which also is revolving. The rotation of the larger
wheel would so influence the smaller wheel that its axis would point
in the same direction as the axis of the larger wheel. Why this is the
case does not concern us here. Let it suffice that the larger wheel
will cause the smaller wheel to behave in this manner. This is in
accordance with a natural law. This law operates as unfailingly as the
law which causes an unsupported body to fall to the ground.

[Illustration: Preparing Master Compass for Test.]

Suppose the larger wheel happens to be the earth, which in reality
is a revolving wheel. Suppose further, the small wheel is a Sperry
Gyro-Compass. In accordance with this natural law just outlined the
smaller wheel, or Gyro-Compass, will point its axis in the same
direction as the axis of the earth, or, in other words, to the true
or geographical North Pole. This explanation of the principle of
gyroscopic motion is necessarily crude. The principle itself has
been established beyond any reasonable doubt. It can be proved by
mathematics to the satisfaction of the most exacting scientist and has
been demonstrated, throughout the navies of the world, to practical
seamen.

The final result is that we have a principle which enables us to
construct an instrument which will place itself in the true geographic
north and south meridian, and that it responds to no influence or
impulse other than the earth’s unvarying rotation.

[Illustration: Galley-slaves drove the Triremes of ancient Rome.]

[Illustration: FIGURE 1.

THE EARTH SURROUNDED BY ROTATING WHEELS AS IT APPEARS TO AN IMAGINARY
OBSERVER LOOKING AT IT FROM THE SIDE.]

[Illustration: FIGURE 2.

THE EARTH SURROUNDED BY ROTATING WHEELS AS IT APPEARS TO AN IMAGINARY
OBSERVER LOOKING DIRECTLY AT THE SOUTH POLE]

[Illustration: A War-ship, “when knighthood was in flower”.]




_How a Compass is Used_


The purpose of a compass is to indicate direction. The relative
position of the North Pole to any point on the earth’s surface is
called North. We figure all direction from this conception. This
geographical North Pole is called the True North. About 800 miles from
this True North Pole is a spot which has a strange magnetic attraction.
The needle of the magnetic compass, if undisturbed by local influences,
points to this spot, and not to the True North Pole. This spot is
called the Magnetic North Pole. This mysterious attractive spot is not
stationary. It moves about from year to year within a wide circle.

Inasmuch as the navigator must refer to True North, he must determine
the angle or variation between True North and Magnetic North as
indicated by his magnetic compass. This determination is made
comparatively easy by using charts which express in degrees the
difference between Magnetic North and True North for any point on the
earth’s surface.

Such a chart is shown in Figure 3. Also on each chart used by a
navigator for a particular locality there is marked a compass rose in
which is recorded the variation for that exact spot as of a certain
date, and in addition the rate at which the variation changes annually,
Figure 4.

Navigation along a coast line where sights can be taken on buoys or
lighthouses is simple, and is termed “piloting.” This, of course, can
be done without the aid of a compass.

[Illustration: Master Compasses Awaiting Shipment.]

Upon getting to open sea the mariner checks his position in a similar
manner, by observing the position of his ship in relation to the
position of the sun, moon or stars. Between observations the position
of a ship is determined by “dead reckoning.” The distance it has
traveled from the last known position is measured by the ship’s log
and the direction is indicated by the compass. Very often for days
at a time, owing to weather conditions, it is impossible to get an
observation or sight on a celestial body. During this run the navigator
is dependent entirely upon the compass. The slightest error in the
compass, due to variation or deviation, in such circumstances will
cause the ship to be miles out of its course, and the actual position
will be far from the calculated position.

[Illustration: Crusaders sailed to Palestine in ships like this.]

[Illustration: Figure 3, Figure 4.]

[Illustration: The Santa Maria carried Columbus to the new world.]




_The Ideal Compass_


If you were to conceive of a compass which would be free from all the
troubles and errors found in most compasses, which would relieve you of
all the worry and care the present compass requires, a compass which
would be accurate and reliable, a compass which would be the Ideal
Compass under all conditions, you would undoubtedly conceive of a
compass that had the following characteristics:

1. It must point True North.

2. It must free you from the necessity of making calculations and
corrections.

3. It must free you from compensating the compass for errors.

4. It must free you from the burden of swinging the ship, or otherwise
taking the deviation of your compass.

5. It must not be influenced by inherent magnetism of the ship.

6. It must not be influenced by any change in the character or
disposition of the cargo.

7. It must not be influenced directly or indirectly by any temperature
changes.

8. It must not be influenced by the roll or pitch of the ship.

9. It must not be influenced by any weather conditions.

10. In the event of failure, or error, it should give instant warning.


Comparison of the Magnetic Compass with the Sperry Gyro-Compass

Let us compare the Magnetic Compass with the Sperry Gyro-Compass and
determine which more nearly approaches the Ideal Compass.

[Illustration]


True North


The Magnetic Compass

The Magnetic Compass does not point to True North, it points to
Magnetic North, which is about 800 miles from the True North Pole.


The Sperry Gyro-Compass

The Sperry Gyro-Compass, which is not a Magnetic Compass, and is not
affected by a magnetism of any sort, and derives its directive force
from the earth’s rotation, points True North. It does not point to the
Magnetic North Pole.

[Illustration: A Galleon, the treasure ship of the Spanish Main.]

[Illustration]


Freedom From Calculation

Every time a ship’s course is laid or changed, or its position noted,
the navigator must make and apply calculations to correct the errors
caused by variation of the earth’s magnetic fields, and deviation due
to local conditions about the ship. Mistakes are frequently made in
applying the correction factors by applying them to the wrong side. An
error is thus introduced, which in magnitude is twice the correction
factor. Instances are reported of ships being 200 miles out of their
courses as a result.

The Gyro-Compass requires no corrections since it is undisturbed by
variations or any local magnetic conditions. The reading indicated
by the Sperry Gyro-Compass is not approximate—it is absolutely and
immediately correct. It is not necessary to correct the course every
few hours for variation—the navigator is freed from the necessity of
making calculations.

[Illustration]


Freedom From Compensation

After the navigator has made calculations for the deviation errors of
the Magnetic Compass, they must be applied by means of manipulating
the soft iron globes and compensating magnets. This is an operation
requiring such a high degree of skill that only trained men called
Compass Adjusters are qualified for the work.

The occasional turning of a thumb nut is the only compensation
necessary in the use of a Sperry Gyro-Compass. No tables or curves are
required. The ship’s Navigating Officer makes this adjustment with
ease.

[Illustration: A Ship of the Line, the dreadnought of former days.]

[Illustration]


Freedom From Checking Deviation

Each time a compass is compensated it is necessary to check the
compensation by checking the deviation on various headings. This may be
done by the use of deflector magnets. A more exact method is to swing
the ship in a circle while bearings are taken of a known object on land
and the deviation noted on various headings. The sun is often taken as
a reference point for this purpose.

It is never necessary to swing ship or to correct the Gyro-Compass
for either variation or deviation of any kind. Where a Gyro-Compass
and a magnetic compass are both used on a ship, the ship may be swung
to correct the magnetic compass—the Gyro-Compass furnishing true
headings. The time required is thereby materially shortened.

[Illustration]


Influences Due to Magnetism of the Ship

When a steel ship is building a sub-permanent magnetism is induced in
its keel, hull, and plates. It causes a compass deviation classed as
“semi-circular.” This deviation must be compensated for.

As a ship moves through the earth’s magnetic fields in its varying
quantities and directions, a temporary and varying magnetism is induced
in the soft iron of the ship. The resultant deviation is classed as
“quadrantal,” and must be compensated for.

The Sperry is not a Magnetic Compass. Hammering, riveting, and moving
through magnetic fields may induce magnetism in the ship, but will have
no effect upon the Sperry Gyro-Compass.

There is no condition of the ship or cargo for which the Gyro-Compass
must be corrected.

[Illustration: An American Clipper, highest type of sailing ships.]

[Illustration]


Influences Due to Cargo

Change in the character or disposition of the cargo of the ship causes
a change in the magnetic fields surrounding the compass. These changes
must be compensated for.

The Sperry Gyro-Compass is not affected by any cargo. A cargo of iron
ore has no more effect upon it than a cargo of cotton. You could even
carry a load of strong magnets without causing the slightest deviation.

[Illustration]


Influences Due to Temperature Changes

Changes in the temperature of the stack, due to shifting of the wind
and force of draft, vary its magnetic characteristics. Consequently the
Magnetic Compass is affected.

Temperature changes do not influence the Sperry Gyro-Compass.

No matter what the conditions are that change the magnetic
characteristics of the stack, ship or cargo, they cannot affect the
Gyro-Compass, as it has nothing whatever to do with magnetism.

[Illustration: Fulton’s Clermont ushered in the age of steam.]

[Illustration]


Influences Due to Roll and Pitch of the Ship


The Magnetic Compass

Another error, called heeling error, is caused by the change in the
disposition of the material of the ship with reference to the compass.
It is brought about when the ship rolls. For example, a ship heading
on a northerly course would, if rolled to port, place all magnetic
material of the ship to the eastward of the compass. This pulls the
north end of the compass to the eastward. The action and effect would
be just opposite to this on a roll to the starboard. The result is that
the needle is caused to oscillate in either direction. The helmsman
in his attempt to keep “on” will cause the ship to traverse a sinuous
course.

The card and needle of the magnetic compass are placed in a bowl
filled with a liquid. The purpose in so doing is to make the action
of the card somewhat sluggish, so that it will not follow very slight
magnetic distractions or ship movements. Every time the course of the
ship is changed the sluggish action, due to adhesion between the bowl,
liquid and card, pulls the compass off the meridian. Official test has
shown that from three to four minutes are required for the compass to
overcome this “lag.” The “lag” is somewhat less in the dry card compass.


The Sperry Gyro-Compass

Not only is the Sperry Gyro-Compass unaffected by magnetic conditions,
resulting from the heeling error, but before being placed upon the ship
it is tested for days under conditions simulating the motion of the
ship in the most severe storm.

A ship steered by the Gyro-Compass traverses a straight line course;
the Gyro-Compass does not oscillate with the rolling of the ship. It is
not necessary for the helmsman to use as much helm to keep the ship on
her course. A great saving is made in the use of the steering engine.

There is no “lag” in the Sperry Gyro-Compass, because it does not leave
the meridian, no matter which way or how quickly the ship may turn or
zig-zag. Exhaustive tests have been conducted on compasses installed on
torpedo boat destroyers. Even when zig-zagging at top speed in heavy
seas the Gyro-Compass shows no “lag.”

Traveling the straight line course instead of the sinuous course, ships
equipped with the Sperry Gyro-Compass have saved from one to ten per
cent in time over the average schedule time required to cover their
courses when steering by the magnetic compass.

[Illustration: The Savannah, first steamship to cross the ocean.]

[Illustration]


Warning of Unreliability

Due to magnetic storms and any number of other causes the magnetic
compass may at any time be distracted so that it does not indicate
correctly. Disturbances are extraneous and their direction and
magnitude cannot be determined. The navigator is constantly subject to
the feeling that his compass may not be accurate—that he cannot depend
on it.

About the only thing that will cause an error in the Gyro-Compass is
the failure of the electrical power supply. Should this contingency
occur an electric bell warns the navigator. Any disturbances must
originate with the master compass and can be quickly and accurately
located.

       *       *       *       *       *

The Sperry Gyro-Compass unfailingly points True North under all
conditions of weather, ship or cargo. It relieves the navigator of
calculation of errors, and tiresome compass compensations. It makes a
great saving in time required to “swing ship.” The Sperry Gyro-Compass
is, therefore, the Ideal Compass.

[Illustration]

[Illustration: The Great Eastern laid the first Atlantic cable.]




_Advantages Attending the Use of the Sperry Gyro-Compass_

During the construction of a steel ship it is usual to build it on ways
the direction of which lie in the East-West line. Should the ways be
placed in a North-South line the riveting on the keel and plates tends
to help the molecules of metal to place themselves parallel to the
magnetic lines of force, and magnetize the metal. When placed in the
East-West line the molecules of metal in the plates are at right angles
to the magnetic lines of force, and are not as easily magnetized. The
use of the Gyro-Compass eliminates the necessity of placing the ways in
the East-West line.

After a large ship has been launched, and during the fitting out
period, it is often necessary to have it swung end for end in order to
neutralize or equalize the magnetism induced by the earth’s magnetic
field. To swing a large ship end for end costs anywhere from one
thousand ($1000) to three thousand ($3000) dollars. The Gyro-Compass
is unaffected by any magnetic phenomena, and is so dependable that it
makes the swinging of the ship unnecessary.

In constructing a ship it is customary to make all metal parts within
approximately ten (10) feet of the magnetic-compass stand of bronze,
brass or other non-magnetic material. The proximity of magnetic metals
seriously affects the accuracy of the compass. All electric leads are
run so as to clear the vicinity of the compass, as the magnetic fields
set up by such conductors seriously influence the compass needle.
Actual experience is on record that the total installation cost of the
Sperry Gyro-Compass has been saved many times over by the elimination
of special metals and special run of electric leads.

[Illustration: Gyro-Compass School for Training Ship’s Officers and
Men.]

Before starting on a long voyage, especially with a new ship using the
magnetic compass, it is customary to swing the ship through a complete
circle to check deviation. To swing ship it is first necessary to pick
out a suitable object on land having a known bearing to the ship.
This object is used as a reference point. If at sea observations are
taken on the sun. The ship is then swung through 360 degrees, stopping
usually on each 15-degree heading, and noting the deviation. A table
is made up showing the deviation on each of these headings. An attempt
is then made to so adjust or manipulate the compensating magnets to
eliminate the error found. The ship must then again be swung through
360 degrees, stopping at headings as before to check the applied
compensation.

[Illustration: A Stern-wheeler of early steam-boating days.]

On some ships it is the custom to check the deviation by the deflector
magnet method. The ship in this case is put on a certain heading and a
magnet placed to one side of the compass and the deviation noted. The
same magnet is then placed at an equal distance to the opposite side
and the deviation noted. The difference, if any, between the readings
is the deviation on that particular course.

With either method of checking for deviation, considerable time
is used. It is not necessary to check for deviation or apply any
compensation to the Gyro-Compass, as it is not magnetic. In fact the
Gyro-Compass has nothing whatever to do with magnetism.

When at sea the Gyro-Compass affords the means of keeping to the
straight-line, true course. The line A B, Figure 5, shows the
straight-line course from the port of New York to the port of
Liverpool. The line A C E B shows, with exaggeration, the actual course
steered due to compass and other errors. At the point E the ship’s
position was checked by observation of a celestial body. The line E B
represents the new course set to bring the ship to her destination.
This is an occurrence which sometimes happens not once but often during
a voyage.

[Illustration: Figure 5. Errors of Magnetic Compass Cause Departure
From Desired Course.]

It is evident that a loss of time is involved when the ship leaves her
straight line course. The inherent accuracy of the Sperry Gyro-Compass
enables the ship to keep to the straight line course, and also to steer
directly on true courses.

By keeping on a straight line course the ship is enabled to make a
good many more miles on the same number of revolutions or turns of
the propeller. Under exactly the same weather conditions a 16,000 ton
liner made 370 miles in 24 hours at an average of 86.95 revolutions per
minute per mile when steered by a magnetic compass, and the same liner
made 377 miles with 85.61 revolutions per minute per mile when steered
by the Gyro-Compass. This saving amounts to easily $50 per day for this
ship. During her eleven-day voyage she saved $550. At this rate of
saving the Gyro-Compass equipment is soon paid for.

[Illustration: Steering Repeater in Wheel House.]

[Illustration: The Turbinia was the first turbine steamer.]

The Sperry Gyro-Compass does not oscillate with the rolling of the
ship, or in other words, has no heeling error. The use of the helm
is greatly diminished. Records show that on one trans-Atlantic liner
a saving of 24 percent in the revolutions of the steering engine,
when steered by Gyro-Compass, was effected. One of the largest
trans-Atlantic liners reports that but one-third of the helm is used
when the ship is steered by Gyro-Compass.

This saving in the use of the steering engine gives actual proof that
the ship navigated by a Gyro-Compass steers a straight line course.
It further proves that the ship does not divert its slip-stream as
often—the power output of the main engines is thereby reduced.

Records taken on a well-known passenger liner show that in making her
regular trip between New York and Jacksonville, Florida, she saved more
than two hours due to steering by a Sperry Gyro-Compass. A saving of
3,410 turns of her propeller was also effected. These savings were made
even with much greater than the usual draft.

Records taken by means of the Sperry Recording Compass show that when
the helmsman is given a certain course he can keep the ship one and
one-half degrees nearer the course when steering by the Gyro-Compass
than when steering by magnetic compass.

The Gyro-Compass can make great savings in money both in construction
and operation of the ship. These factors are perhaps trivial when
compared with the safety factor introduced by the use of the Sperry
Gyro-Compass.

[Illustration: High Potential Test on Repeaters.]

Due to the elimination of the many uncertainties of the magnetic
compass, insurance companies are favorably disposed toward the use of
the Sperry Gyro-Compass, which ultimately will result in a reduction of
insurance rates.

The use of the Sperry Gyro-Compass eliminates inaccuracies due to
navigation, thereby saving time, insuring the ship, the cargo, and the
lives of passengers and crew.

Sperry Gyro-Compasses are operating on many of the world’s largest
and fastest passenger liners and cargo ships. These ships are making
savings every day of fuel used and time required to make their courses.
The navigators using these compasses find that they can come very much
nearer their calculated positions when steering by the Gyro-Compass.
The Gyro-Compass makes the art of navigation more exact.

The Sperry Gyro-Compass is the only one to pass the service tests in
the world’s navies.

[Illustration: Schooners are economical, needing but small crews.]




_The Sperry Gyro-Compass Equipment_


The equipment which applies the principle set forth in a practical way
consists of:

1. The Master, True North Compass.

2. Compass Control-Panel—for controlling the electric current.

3. Repeaters—operated from the Master Compass, and indicating its
exact reading at any instant.

4. Motor-generator—for converting the ship’s current into current of
proper characteristics for spinning the gyro wheels and operating the
repeaters.

5. Storage Battery—for emergency operation of the equipment in case of
failure of the ship’s supply.

The function of each piece of equipment and its relation to other parts
is shown on pages 22 and 23.


The Master Compass

The Master Gyro-Compass is contained within a binnacle stand, with
glass dome top.

As shown in the photographs and sectional view, the twin gyro-wheels
are supported from a frame-work which is in turn set in gimbal rings.
The outer gimbal ring is attached to the binnacle stand by means of a
number of supporting springs. The springs are provided for protecting
the compass against sudden jars and vibrations. Figure 18 shows a
photograph of the top view, while the wheels are shown from below in
Figure 16.

A diagrammatic representation of the Sperry Gyro-Compass is shown in
plan view in Figure 17. The elevation, or side view, is shown in Figure
15. These drawings show the working parts of the Gyro-Compass. Each of
the twin gyro-wheels is enclosed in a case, which is in turn suspended
from the main frame and spider.

The wheels are spun at a high speed in unison by means of electricity.
The force of the earth’s rotation combines with the force resulting
from the rotating wheels. The resultant action of these two forces is
that both wheels turn their axes directly into, or parallel with, the
earth’s north and south meridian. The compass card, of course, also
turns and indicates direction by comparing the stationary “lubber
line,” representing the ship’s head, with the compass card.

[Illustration: Using Bearing Repeater at Sea.]

[Illustration: The trade of China is carried in clumsy Junks.]

[Illustration: Figure 6. Control Panel.

Figure 7. Motor Generator.

Figure 8. Master Compass.

Figure 9. Storage Battery.]

[Illustration: Steel Square-riggers still compete with steamers.]

[Illustration: Figure 10. Repeater on Steering Stand.

Figure 11. Repeater, Bulkhead Type.

Figure 12. Bearing Repeater in Pelorus Stand.]

[Illustration: The Dhow is the trading ship of East Africa.]

[Illustration: Figure 14.]

A single gyro-wheel would constitute a satisfactory stationary, or
“land compass.” On shipboard the roll, yaw and pitch of the ship would
impose additional duty on a single wheel. It would have to point not
only True North, but also offset the effect of the sea. One of the two
wheels is arranged to always point True North, while its twin wheel
opposes and neutralizes all influences other than the force of the
earth’s rotation. The force of both wheels is utilized in seeking the
meridian.

The Master Gyro-Compass is a marvel of mechanical perfection and
ruggedness. Every rotating or revolving part moves upon special
bearings to reduce friction. It should be noted also that the
gyro-wheels do not directly operate the compass card. The compass card
is turned by a small electric motor (Azimuth Motor), Figure 17. The
slightest change in position between the wheels and card operates the
“trolley” or electrical contact, which controls the Azimuth Motor. The
card is made to “shadow” the wheels. The follow-up is so close that the
card frame has been called the “phantom.”

An electrical transmitter, Figure 17, is operated by the movement of
the card. This transmitter is the means by which the repeaters are
kept in unison with the movements of the Master Gyro-Compass, and made
to show the exact reading at any instant. Again the Azimuth Motor
furnishes the very slight amount of power required to operate this
device.

[Illustration: Figure 13.]

The Master Compass is placed near the center of the ship at the water
line. At this point the effect of rolling is at a minimum. It is,
however, not necessary to place it exactly at this position. Figure
13 shows the approximate location of the various pieces of equipment
aboard ship.


The Repeaters

[Illustration: An indispensable link between producer and consumer.]

A familiar application of the repeater principle is that used in
hotels and public buildings, where a number of repeater clocks are
operated from one master instrument. Likewise, the repeater used upon
the bridge, the bearing repeater, and the one at the after steering
station, are all operated by electricity in perfect unison with the
Master Gyro-Compass and show the exact reading of the Master at any
instant. Repeaters are operated by a small electric motor within each
case, controlled by the transmitter at the Master Gyro. In designing
the repeaters particular attention has been given to the electrical
circuits so as to make all connections water, spray and condensation
proof. Stuffing tubes of improved design are used at all outlets and
entrances.

A miniature electric lamp within the repeater supplies the necessary
illumination of the dial. The illumination can be brightened or dimmed
by turning the switch handle on the face of the terminal box.

The repeaters are supplied in three styles:

1. Repeater mounted on steering stand—for use on bridge.

2. Bearing repeater mounted within pelorus stand.

3. Repeater mounted on bulkhead in Master’s room, or at the after
steering station.

Special stands or fixtures can be supplied if necessary.

A metal “non-reflection” cover is supplied which can be fitted to
either the bridge or the after steering repeaters. The cover has
adjustable doors and a hood. Its object is to exclude all light from
the top glass of the repeater except at the lubber’s line. No light
will be reflected into the eyes of the helmsman. The doors can be
closed until a very small sector of the repeater dial appears at
the lubber’s line. Experience has proved that it is easier to watch
and concentrate when only a small portion of the dial is visible. A
magnifying glass can be used in conjunction with the cover so that the
repeater indication can be read at a distance.

[Illustration: Bearing Repeater with Sperry Azimuth Circle.]

The bridge and after steering repeaters are mounted on adjustable
brackets. The position of the repeater can be changed so as to allow a
full face view of the dial from almost any angle.

The bearing repeater is of great aid to the navigator. The repeater
is mounted within the stand and, of course, shows the exact reading
of the Master Compass. In taking a bearing on a distant object or
a sun azimuth it is not necessary to first set the “dumb” compass
to correspond with the main compass. A constant true indication is
afforded.

Installation of the bearing repeater can be made in such a position on
the upper bridge so that it may be used for steering from that position
as well as for taking bearings. A special pelorus stand cover can be
supplied with windows to allow steering with the cover on, so as to
protect the repeater from spray and the weather.

[Illustration: The light unsinkable Kayak of the Eskimo.]

[Illustration: Figure 15.]

[Illustration: Figure 16.]

[Illustration: An Ore-steamer of the American Great Lakes.]

[Illustration: Figure 17.]

[Illustration: Figure 18.]

[Illustration: The great painted War-Canoe of Alaskan Indians.]

An improved design of azimuth circle is furnished which fits directly
over the top of the repeater. Figures 24 and 26, on page 30, show
the azimuth circle and bearing repeater in use, taking a bearing on
a distant object, and on the sun respectively. This azimuth circle
is so constructed as to bring the object, the spirit level and dial
within the field of vision concurrently. The bearing can be taken with
great accuracy. There is no possibility of the Master Compass changing
its position while the pelorus is in use. Such an occurrence is not
uncommon when using the ordinary pelorus or “dummy” compass.

An additional graduated ring, Figure 25, is supplied for placing under
the azimuth circle so that in case the Gyro-Compass is not operating
such, for instance, as when the ship is at anchor, the pelorus can
still be used as a “dumb” compass. The main compass setting is made
upon the ring, and the azimuth circle used in the usual manner.

The bearing repeater can be furnished with any one of three kinds of
azimuth circles. The Ritchie circle is usually supplied. The purchaser
also has the option of choosing either the Sperry circle or the Kelvin
Azimuth Mirror.


Compass Control-Panel

The compass control-panel provides a means for controlling the
various electrical parts of the Gyro-Compass, the storage battery,
motor-generator and ship’s supply current. It is very compact, neat,
and of good appearance. It receives electrical power from the ship’s
mains and distributes it to the motor-generator set, Master Compass and
repeater.

The switch panel is made up of black ebony asbestos, mounted upon angle
iron. The panel is usually mounted with its back near the bulkheads,
but so hinged as to admit of access to its rear.


Motor-Generator

The Motor-Generator supplied is an efficient and exceptionally reliable
piece of equipment. Its purpose is to convert the ship’s supply
current into electricity of the characteristics used in spinning the
gyro-wheels and operating the repeaters.

[Illustration: Line of Precision Lathes.]


Storage Battery

The complete failure of the electrical plant aboard a modern ship is
an event of rare occurrence. If, however, such a contingency should
occur, provision has been made for it in the Gyro-Compass equipment
by supplying a storage battery of sufficient capacity to operate the
entire equipment for a period of two hours. The battery is so connected
electrically as to keep itself in a charged condition while the compass
is operating under normal conditions.

[Illustration: A Super-dreadnought, the bulwark of sea power.]

[Illustration: FIG. 19, FIG. 20, FIG. 21, FIG. 22, FIG. 23.

Sperry Gyro-Compass Repeaters.]

[Illustration: The Dahabeah is the passenger boat of the Nile.]

[Illustration: FIG. 24, FIG. 25, FIG. 26.

Sperry Gyro-Compass Bearing Repeater With Azimuth Circle.]

[Illustration: A fast-steaming hotel for ocean travelers.]

[Illustration: FIG. 27, FIG. 28, FIG. 29, FIG. 30.

Bearing Repeater Mounted in Pelorus Stand.]

[Illustration: Malay pirates use the swift-sailing Proa.]

[Illustration: Figure 31.]


Sperry Recording Compass

An outstanding feature of the Gyro-Compass is that it makes possible
the recording of the actual courses steered by a vessel. The recording
compass is connected to the electrical circuits like a repeater and
follows the movements of the Master Compass. It not only indicates the
heading at any instant, but also makes a graphic record on a chart.
Radial lines on the chart represent the various courses. Concentric
circles represent time—each small division five minutes—each large
division one hour.

The dial on which the chart is mounted turns with the movements of the
master compass bringing the correct course under the marking point.
As the time advances a line is marked on the chart showing the exact
course steered at a definite time. On starting, the marking arm is at
the inner edge, clockwork moves it toward the outer edge with uniform
motion.

[Illustration: Figure 32.]

The chart shown in Figure 32 forms a valuable record. It was taken on
a ship at a time a radio call was received from a burning oil tanker.
Being within the distance defined by law, the ship was legally, as well
as morally bound to proceed to the distressed ship. The chart shows
that the course was altered to go to the tanker’s aid. It also showed
the exact time, thereby establishing proof as to the fulfillment of
the obligation. A few minutes later another radio call advised that
the fire aboard the tanker was extinguished. The chart shows that the
course was again altered to bring the vessel back on her original given
course.

[Illustration: The Destroyer is the grey-hound of the sea.]

The chart further shows the actual courses steered in holding the ship
on its given course. It shows just how efficiently each helmsman
handles the ship. It provides an excellent method of training helmsmen
to use less helm, effecting a saving by less frequent use of the
steering engine.

The recording compass is a great aid to the Captain and Navigator in
improving the navigating efficiency of the ship.

The recording compass can be supplied as a part of the Gyro-Compass
equipment—its additional cost is small when compared to the saving and
benefits derived from its use.


Operation

The operation of the Sperry Gyro-Compass is made easy by making all
parts as simple as possible.

In starting the equipment it is necessary to turn but one switch. The
twin wheels immediately start spinning and will in a short time come up
to the normal speed.

After the speed has been attained, a short time is allowed for the
wheels to cause their axes to “settle,” or, in other words, to seek and
hold the meridian.

In case of failure of the ship’s supply, or other trouble, an audible
signal immediately gives indication that something is wrong. This is
a decided improvement over the ordinary compass, as no indication is
afforded of the presence of factors which cause errors in its reading.


Care

All of the greatest commercial aids require some care, such, for
instance, as the telephone, typewriter, adding machine, duplicating
machine and so on.

[Illustration: Bearing Repeater Equipped with Windows in Storm Cover.]

The magnetic compasses aboard ship receive especially watchful
attention, to see that they are not meddled or tampered with. As a rule
the entire ship’s crew, including the youngest apprentice, knows that
the compass must in no way be handled.

It should be remembered that the Sperry Gyro-Compass is a mechanical
compass. Although the very best materials, design and skill enter
into its construction, it is still liable to failure. Even with that
possibility, it is so superior to the magnetic compass that it more
than justifies its installation use. In the same way the electric
light, although liable to failure, is vastly superior to the old oil
lamp. The oil lamps are seldom used, yet they are carried aboard ships
for the contingency which might happen. Similarly a failure of the
electric or hydraulic steering gear may necessitate the temporary use
of the inefficient hand-steering gear.

[Illustration: In Venice, graceful Gondolas take the place of cabs.]

[Illustration: Fig. 33. Repeater at After Steering Station.

Fig. 35. Repeater on Wing of Upper Bridge.

Fig. 34. Bearing Repeater on top of Wheel-house.]

[Illustration: Steam-yachting is the most costly of all sports.]

[Illustration: Fig. 37. Bearing Repeater.

Fig. 36. Repeater at Steering Station.]

[Illustration: The Mediterranean Felucca, swift in all weathers.]

[Illustration: Fig. 38. Master Compasses on Long Run Floor Test.

Fig. 39. Master Compasses under Test on Special Machine constructed to
simulate the motion of a Ship in a Heavy Sea.]

[Illustration: The Submarine, the unseen terror of the seas.]




_Sperry Service_

When a Gyro-Compass is sold the interest of The Sperry Gyroscope
Company does not cease. Our interest in our customer is only beginning.
An experienced service engineer installs every Sperry Gyro-Compass.
This engineer is also available to make the first trip with the compass
in order to assure its proper operation. After installation the Sperry
Service Engineers are available in every large port in the world to
come aboard and inspect, clean, repair and overhaul the Gyro-Compass
equipment so as to keep it in first class operating condition. A
radiogram sent to any of the Sperry Service Stations will bring a
Service Engineer to meet your ship. During the first year there is no
charge. After this period a reasonable charge is made for the service.
Such a charge is similar to that at present made by compass-adjusters.

A list of the Sperry Representatives is given on the title page of this
book.


Workmanship

[Illustration: Ritchie Azimuth Circle in Use on Bearing Repeater.]

The Sperry Gyro-Compass is an instrument of precision. From the work
done by the Gyro-Compass and the objects accomplished it would be
natural to class it as a scientific instrument. It is, however, more
than that for the reason that it has been made strong and sturdy for
operation under the most severe conditions at sea. The most expert and
skilled workmanship is required to combine strength and precision, such
as found in the Gyro-Compass. The Sperry organization prides itself
upon having the best workmen that can be obtained for their respective
vocations.

The materials used are the very best obtainable. The rigid and
inflexible set of purchasing specifications insures receiving the best
materials.

A well organized inspection force passes upon all material upon its
receipt, and through the various manufacturing stages to the final
product.

[Illustration: The Sampan shoots the rapids of Japanese rivers.]

Testing

Each Sperry Gyro-Compass is on test for several days. During this time
it is put through every devisable test to simulate the conditions
under which it will have to operate. Figures 38 and 39 show a compass
mounted on a stand which is operated by means of motor driven gears,
cams, etc., so as to reproduce the roll, pitch and yaw of a ship at
sea. Absolute accuracy of the Master Compass and all repeaters while
operating under this condition is required.

The purchaser is thereby assured that the compass to be installed upon
his ship will have had all manufacturing inaccuracies or so-called
“kinks” worked out. A record of the test accompanies each compass.


Packing

Special care is taken in packing the Gyro-Compass for shipment.
Experience gained from the shipment of hundreds of compasses has
devised means whereby to insure the safe arrival of all parts so that
installation will not be delayed.

In order that no injury may result to any parts, the Gyro-Compass is
unpacked under the supervision of the Sperry Service Engineer.


The Sperry Service Organization

The Sperry Service Organization is one which serves in all parts of the
world. A corps of Service Engineers, having special training at the
factory in all departments relating to the Gyro-Compass, are available
in nearly every large port of the world. These engineers are ready to
come aboard your ship, to clean, adjust and overhaul the Gyro-Compass,
thus relieving the navigator of all care other than the actual use of
the Gyro-Compass.

[Illustration: Master Compasses on Testing Machine which simulates the
Roll, Pitch and Yaw of Ship at Sea.]

During the war we had Service Engineers in every port where the ships
of the Navy were likely to call. Our men have been in many of the
naval actions and have been able to render very considerable service
on many unusual occasions. For example, it was desired to place an
equipment on a British ship which was on her way to the Dardanelles.
The Admiralty instructed us by telegram to have an equipment and a
Service Engineer meet the ship at the British Naval Station at Malta in
the Mediterranean. By sending the equipment with our Service Engineer
via a passenger train to the south of Italy and via destroyer to Malta
we were able to meet the ship there on the day she arrived. The ship
was able to stay only twenty-four hours, and as it took about four days
to install the equipment, our engineer remained on board and finished
the work while the ship was enroute from Malta to the Dardanelles.

[Illustration: The Whale-back, steadiest of all in rough weather.]

This ship, the _Inflexible_, arrived at the Dardanelles just in time
to join in the first naval action directed against the land batteries.
During the first part of the engagement our engineer remained with the
Master Compass which was installed near the dynamo room. When he saw
that it was functioning properly he left it to go on deck and view the
action, the effects of which he had become aware of, as a number of
shells from the land batteries had hit the ship. Almost immediately
after he arrived on deck a torpedo struck the ship directly under the
compartment where the Gyro-Compass was located, killing every man in
that compartment. Although badly damaged the ship was able to get
out of range of the land batteries and reach the naval base near the
Dardanelles.

The Gyro-Compass was, of course, almost totally destroyed. Shortly
after the action ended our engineer was enabled to get ashore on a
Greek island via one of the British destroyers. This island had a
telegraph station which he used to cable us that “Equipment No. 286 is
under four feet of water,” and that we should have another equipment
ready to replace it. We took this telegram to the Admiralty who
authorized us to have another equipment prepared to meet this ship
at Gibraltar. This we did, again sending a Service Engineer who met
the ship at Gibraltar, on her way back to England to be repaired and
refitted.

The Sperry Service Organization stands ready to help all ships equipped
with a Gyro-Compass at all times, even in emergencies such as those
experienced by naval vessels.


Service Given to the World’s Navies by the Gyro-Compass

[Illustration: Steering from Bearing Repeater.]

[Illustration: The Coracle of ancient Britain, still used in Wales.]

At the time of the battle of Coronel on the west coast of South
America, H. M. S. _Invincible_ was being overhauled at the Portsmouth
Dockyard in England. She was immediately ordered with one other large
British ship to South American waters under the command of Admiral
Sturdee, to re-enforce the British fleet, and then to find and destroy
the German ships which had defeated the British at the battle of
Coronel. When the overhaul of the _Invincible_ was completed and she
was ready to leave the docks, it was at first planned to delay sailing
until the ship could be swung and the magnetic compasses compensated.
It was decided, however, that although the compasses were badly in
need of adjustment it was necessary to save every minute in order to
reach South American waters before the German ships could find and
destroy the British ships remaining in those waters. The _Invincible_
therefore sailed without adjusting her magnetic compasses and navigated
entirely by the Sperry Gyro-Compass from Portsmouth to the Falkland
Islands. When an azimuth was finally taken the magnetic compass was
found to be out about 22 degrees. The _Invincible_ arrived at the
Falkland Islands just in time to coal before the German fleet appeared.
If H. M. S. _Invincible_ had not had a Gyro-Compass the probabilities
are that she would not have reached the Falkland Islands in time to win
the battle which took place almost immediately upon her arrival.

Figure 49 shows a British submarine, a sister ship of the E-11, that
entered the Sea of Marmora through the Dardanelles for the purpose of
destroying Turkish and German shipping. The E-11 put a torpedo right
into Constantinople harbor. The Second Officer of the E-11 in relating
this exploit, stated that they steered by the “Sperry” all the way in
and out. His remark was that, “It never let me down.”

In this exploit, and many others of a similar nature, the Gyro-Compass
was used for all navigation. These extremely daring and hazardous
operations would not have been possible without this instrument.

A similar British submarine left Harwich on the east coast of England,
and during a period of three weeks made seven patrol trips, and without
once seeing the sun, finally returned to Harwich and picked up the buoy
at the mouth of the harbor without the least difficulty. The navigation
in this case was carried out entirely by the Gyro-Compass.

[Illustration: Repeaters on Test.]

Figure 54 is a photograph of H. M. S. _Lion_, the flagship of Admiral
Beatty in the battle of Jutland. This ship was provided with the Sperry
Gyro-Compass equipment early in the war. During the Jutland engagement
a fire broke out in a magazine of the _Lion_ immediately below the two
Master Compasses which were located in one compartment. It became so
hot that the lead sheathing was melted off the electric cables and one
of the Gyro-Compasses was heated until its parts fused. Notwithstanding
this same heat the other compass functioned throughout the entire
action. Of the ships engaged in the battle of Jutland practically all
except the destroyers were equipped with the Gyro-Compass. Every one of
them performed perfectly throughout the action except in the case of
the _Lion_ on which one was destroyed by fire.

Hundreds of Sperry Gyro-Compasses are veterans of many battles and
encounters under heavy gunfire and adverse conditions.

[Illustration: The Power Boat, small, able, reliable, comfortable.]

[Illustration: 40. R. M. S Bergensfjord. 41. R. M. S. Aquitania. 42. S.
S. Lenape. 43. S. S. Conneaut. 44. Yacht Lyndonia.

Ships Equipped with Sperry Gyro-Compass.]

[Illustration: Huge Dug-Outs are used on African rivers.]

[Illustration:

 45. U.S.S. Pennsylvania—
 © E. Muller, Jr.

 46. U.S.S. Bush.

 47. H.M.S. Invincible—
 © Underwood & Underwood.

 48. R. F. La Marsellaise—
 © Underwood & Underwood.

 49. H.M. Submarine E-11—
 © Underwood & Underwood.

Ships Equipped with Sperry Gyro-Compass.]

[Illustration: Great Colliers carry coal for the world’s navies.]

[Illustration:

 50. H. I. M. S. Kongo—
 © Underwood & Underwood.

 51. H. M. S. Conte di Cavour—
 © Underwood & Underwood.

 52. U. S. S. Delaware—
 First Ship to Carry Gyro-Compass.

 53. H. M. S. Queen Elizabeth—
 © Western Newspaper Union.

 54. H. M. S. Lion—
 © Underwood & Underwood.

Ships Equipped with Sperry Gyro-Compass.]

[Illustration: Speedy Ice-boats provide thrilling winter sport.]




 Telegrams Inland: SPERIGYCO, Vic, London.
           Foreign: SPERIGYCO, London.
 Telephone, 7398 VICTORIA.

 THE SPERRY GYROSCOPE COMPANY, LTD.

 NEW YORK—LONDON—MILAN—PARIS PETROGRAD—TOKIO—COPENHAGEN
 STOCKHOLM—LA HAGUE

 15, VICTORIA STREET,
 LONDON, S. W.

 August 1st. 1916.

 B-3909.

 The Sperry Gyroscope Company,
 NEW YORK.

Gentlemen,

It gives me very great pleasure to inform you that my Company has
received from Their Lords Commissioners of the Admiralty, under date
20th July, the following words of commendation:―

 “I am to add an expression of Their Lordships’ appreciation of the
 valuable assistance rendered to the Admiralty by your Company since
 the outbreak of War, in your very prompt and efficient execution of
 the important work entrusted to you”.

I might mention that this was the first recommendation given to a
private Firm by the British Admiralty for fifteen years, and had to be
concurred in by no less than thirty-seven Government Officials.

 Very truly yours,

 THE SPERRY GYROSCOPE COMPANY LTD.

 [Illustration: signature]

 Managing Director.




TRANSCRIBER'S NOTE

Original spelling and grammar are generally retained. Illustrations are
moved from inside paragraphs to between paragraphs. Original italics
_looks like this_. Original small caps is converted to uppercase.

Page 21. The second and third list items under the heading "_The Sperry
Gyro-Compass Equipment_" were incorrectly labeled "3." and "2.", in that
order. These labels were corrected.