Skip to main content

Full text of "The Sperry gyro-compass"

See other formats







Copyright, 1920 


Brooklyn, N. Y.. U. S. A. 






The Sperry Gyroscope Co. 










The S perry 


^rvnrrvv'^ ■^fflf? ■f*-wrT"f<v<^f<'fW'«V''rtCT-r«yvcg-r 

Man's first venture in shipbuilding was the Raft 




Boston, Mass. 

Great Lakes District 


Cleveland, Ohio 

San Francisco, Cat. 

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




37, Rue Bergcre 



20. Rue Taitbout 



20. Rue Taitbout 




Victoria 2 



Naasauliade 17 



Via BaKutU 24 







11 Kobmagagade 




Skovveien 39 





(For Ship Stabilizer) 

Chili, Peru ^ Bolivia 


25 Broad Street 

New York 

^i>s^ yu,\ 

The S perry 

nfCtVfyrtVlJ.yv^ymi t^-fvci. . ^'L-..-t\-^-i.-iYvvr-ryfyf< y 


w / 

An inflated oz-skin Balsa of earliest timea 





Manufacturers of 

gyro-compasses gyro ship stabilizers 

gun-fire control apparatus navigational instruments 

Naval and Commercial Searchlights 

'■•'***i Tf ■"'■—'^^r*' 


iwuMrm wo u BC B c u 

The S perry 




TLt aiuifiit |■;^;>l.tlaIJ^ Imilt Iniultsuf ruslu-.- 


Putting the Earth to Wpj'k ; ;: 

|HEN the earth was thrown off from the si'm. 'and,. "(j<fltiitHB,rt'ced 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, 
hut 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 develop- 
ment 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 compensa- 
ting 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-Com- 
pass 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. 

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 

liiiiiiiit.' Ki fji iilrr 
■ m 1 |'|MT Hrlclpi- 

''7'^^^''^'^"^^ ^ r T-~' ' '. 


The S perry 

.&R0-C0MPASS. f)^ 



e -'— ■ :i 

The Vikings crossed the Atlantic in open slups 

estimated that inaccuracies in, navigation attending the use of the magnetic compass 
cause a yearly':k)$s of-.ships; tp: the value of $70,000,000. No estimate can possibly be 
made on the.vfilue.iQf .U-ves lost oh these ships. 

Milliong-Bf^d^ilars are' spent ieach 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 unvary- 
ing 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. 

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 estab- 
lished 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 con- 
struct 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. 

V'ri[wrinf; \Iaslir 
( '.oiiipass for T<'sl 


niimfiTro cccnBi 

M''*^*^'i'r i 1 1 ■■■**WT 


The S perry 





Galle>'-&lavcs druve the Triremes of ancient Rome 

sou-ni Pole 
FiauRE 1 


FlQ'UR.E 2 

Wi-iEELS A5 IT Appears To An iMAQiNARt 
Observer, Loownq Diuectly At The 
50UTH Pole 


' l iBr i iHHft'ruYri > 'TMn ocB 

The S perry 


•^^TfTc c rTr.-^yyn^'^ 


-^- Y i ^^vT>^^■^;:i-^ ^ y^ . >ryI>: yT-^>^v\^ l.x^^-^\x^^L^^-^'^v^Yir^ :a:J■^^.^l^^ 

A War-diip, "when knighthood was in flower" 

How a Compass is Used 

I HE 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 com- 
pass. 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. 

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 com- 
pass. 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. 

AwjiiliiiK Shipmenl 


f.-.r.^y^ff^,r« ->T-fyv^-«T. ^ot HJrfewtOttXl 

The S perry 



( rusiuliTs sailed to Palestine in shipe like this 


Figure 4 


. ycco c rcc c n B n ocn o oMt 

The S perry 



l. V.>,-~^~^~.^ rr.-rr.,-,v^.-->»-or.T«vtvvVT< 




The Santa Maria carried Columbus to the new world 

The Ideal Compass 

F 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 com- 
pass 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: 

It must point True North. 

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

It must free you from compensating the compass for errors. 

It must free you from the burden of swinging the ship, or otherwise taking the 

deviation of your compass. 

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

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

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

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

It must not be influenced by any weather conditions. 

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 deter- 
mine which more nearly approaches the Ideal Compass. 

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. 

-"^n"* ■■*•'■■ 'I' 



The S perry ff 




A (lalleiin. the trriksur'- sliip of the Spiiiil^h M;iin 

Freedom From 

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 im- 
mediately correct. It is not necessary to 
correct the course every few hours for vari- 
ation — the navigator is freed from the neces- 
sity of making calculations. 

.; oa, 

Freedom From 

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 com- 
pensating magnets. This is an operation 
requiring such a high degree of skill that only 
trained men calle<l 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. 


rk-f;iL'Y^-c,« , «SrtfyyP 


Vl^^^^lT^ '■■■■■ ■■■-ntwt^t^twcvt^ 

Freedom From 

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. 

Checking Deviation 

It is never necessary to swing ship or to 
correct the Gyro-Compass for either varia- 
tion 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. 

Influences Due to 

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 mag- 
netism is induced in the soft iron of the ship. 
The resultant deviation is classed as "quad- 
rantal," and must be compensated for. 

Magnetism of the Ship 

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 cor- 


.*ijir,«jim'ifc»rctTnx i 


The S perry 




An American Clipper, liinliest lypc of sailing ships 

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 mag- 
nets without causing the slightest deviation. 

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 

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. 

■-'■'^'■^"'" ^-.^^^^'-^ 


The S perry 


■ . . , f .-«^^f ...... ^. . .>^v>^->^r^ 

Fulton's Clermont nslicred in tlic uge of Bteam 

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 

The Sperry Gyro-Compass 

Not only is the Sperry Gyro-Compass 
unaffected by magnetic conditions, resulting 
from the heeling eiTor, 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 helms- 
man 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. Ex- 
haustive tests have been conducted on com- 
passes installed on torpedo boat destroy- 
ers. Even when zig-zagging at top speed 
in heavy seas the Gyro-Compass shows no 

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 aver- 
age schedule time required to cover their 
courses when steering by the magnetic 



' '' .,,v 


The S perry 

^---^'^-"^^''r''-*'''*^^'''''*^'*^ <:i inorTr-c 


r't>-'''^''1 VTl-''""^^!'' 


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 ex- 
traneous 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. 

Warning of Unreliability 

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 orig- 
inate 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. 



The S perry 




The Great Eastern laid the first Atlantic cable 

Advantages Attending the Use of the Sperry Gyro-Compass 

fURiNG 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 mag- 
netized. 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 com- 
pass. 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 experi- 
ence 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. 
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 

H^ ^ ^^^H^^^^^^^^^^^^^K^ i ^^m ^^^ ^^^' ^^^ ^^^^ ^^ ^^^^ swung 

■ ""'^ ^^^^^^^^^^^^^^K^ ^^H through 360 degrees, stopping 

P ^s^^K/f^^^^^^^^K^Mm ^^H 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. 

Ciyro-Coiripass SIkriI for 
Training Ship's Ofliofrs and Men 


Ycri-ftYfTrffvmri i ^vmiftMi 

The S perry 


rrremoi-nnu i nuT j 

A Stern-wheeler of early steam-boating daya 

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-Une, 

true course. The Hne A B, Figure 5, shows the straight-Une 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. 

Errors of Magnetic Compass Cau^D^parture From Desired Course , . ^^ *f evident that a loSS of time 

is mvolved 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 Hner 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 sav- 
ing amounts to easily $50 per day 
for this ship. During her eleven- 
day voyage she saved $550. At 
this rate of saving the Gyro-Com- 
pass equipment is soon paid for. 

XciTiiiif Hc|)<>at«:r 
in W luM-l Hoiisi- 



The S perry 


Pt TTv^^^ M lT^^'^^'T^'l^''^''"^ 

The Turbinia was the first turbine steam er 

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 

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. 

Due to the elimination of the many uncer- 

P,^^^^^ tainties of the magnetic compass, insurance com- 
1 _9i|^H panics are favorably disposed toward the use of 
' ^^Hl the Sperry Gyro-Compass, which ultimately will 

I '* ^^M result in a reduction of insurance rates. 
I r^!^-s s- ^ The use of the Sperry Gyro-Compass elirai- 

I {'-.atmlttK^^ nates inaccuracies due to navigation, thereby 

PH I saving time, insuring the ship, the cargo, and the 

^ / lives of passengers and crew. 

~\ f 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. 

, I'oti-iiiNir Ti'si 

M lli'|»fnt<*rs 

ni r trirriirTrrrr-iTrrn — 



The S perry 


-^'rP''"^ ^-"fTTP'^''^^^ rtr^^actt ^ jJc^-^tc 

Sflhmnerfi arr <.vuik>iiiK'u!. neoiniK l>iit ^luull t.TeM 

The Sperry Gyro-Compass Equipment 

HE equipment which apphes the principle set forth in a practical way 
consists of: 




The Master, True North Compass. 

Compass Control-Panel — for controlling the electric current. 
Repeaters — operated from the Master Compass, and indicat- 
ing its exact reading at any instant. 

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

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 at- 
tached 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 elec- 
tricity. 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 com- 
paring the stationary "lubber line," 
representing the ship's head, with 
the compass card. 



Hep«iator on Slwrint; St^iiid 
»^ ^ ■7V'^■^^.^^^i■' ■ ^<^vr g TT^^ i tcttt oss 

■C-?CT-TOCtXir-rfC.»^<-c«^t'^«.i^~rf-f.-.>r.p ,- ^ yyt>.,.,<,< s ,^^ 


The S perry =. 


The Dhow ig the txading ship of East AMoa 

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. 

Fiffure 11 

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 

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 



The S perry 


An indispeiisable link between prudutM-r mid i-uiisiimt-r 

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. 

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 azinuith it is not necessary 
to first set the "dumb" compass to correspond 
with the main compass. A constant true indica- 
tion 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 w ith w indow s 
to allow steering with the cover on, so as to pro- 
tect the repeater from spray and the weather. 

Bt'iiciiijr I<c[>riitcr v 
S|H'rr\ V/.iiiiutli 




The S perry 




The U^t uoflinkable Kayak of the Eskimo 


Tneia Action In Seeking TtiE necioiAN 
But Neutcal^ze In Each Otmee Any 
Effect Which Tme Smip's D.olung 

And Pitching Mav CauSE 

Tme Beadings On 
WmcM The Wheels Dotate 

Figure 15 

Figure 16 

r-^'^""'" ■■ V ^ » ■. 1 Tincet- 


/^$\ The S perry 


Qtro-Compass (i 

An (_>re-8t*aii)er of the American Great Lakes 

Figure 17 

Figure 18 


The S perry 

inffgyfl c gfi c cg a: 


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 re- 
peater 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. 


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 spin- 
ning the gyro-wheels and 
operating the repeaters. 

Storage Battery 

The complete failure of 
the electrical plant aboard a 
modern ship is an event of 
rare occurrence. If, how- 
ever, such a contingency 
should occur, provision has 

Trrrf' MM ' i "' ^ 



etrtfu'iiii im. 



The S perry 


- -rcna 

A t^uptir-drt-aJiiuuKliI.. llif Ijuluark vi M-a |>uwff 


■-^•^y. -■-■^r-^.r»>->^>-^-Y^Yr— ^T^7— fV 

The S perry 

r^firg^-^^'^nf''-'''^'''" ■"•'■■--^-■^•^"-"-<^«^»-<''*t*-*'W'^ 

ii i.icn--. ^ijtii.i 

. :i^L- rry<-rvjtV^c-.-i-rt-r» 


The S perry 

''«^*-^ •^^''^^'^'^-T''X^ ^ ff l TfrT<^^TTrrv^^Tr^r^^^ 



Malay pirates use the swift-sailing l*r(i:i 


Figure 31 

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. 

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. Concen- 
tric 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. 

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 burn- 
ing oil tanker. Being within the distance 

defined by law, the ship was legally, as well 

as morally bound to proceed to the dis- 
tressed 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. 
The chart further shows the actual 

courses steered in holding the ship on its 

Figure 32 







"'- N-^->r^r^-yx-c-t-t-irr\r-tvyvv-:ffV\-r 


The S perry 

. tMi^ H aJAiJ S ^ 



The Deatroyer a the (njr-houiid of tiw an 

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. 


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 inunediately 
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. 


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

The magnetic compasses aboard ship re- 
ceive 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. Al- 
though 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 

I3eariii, , 
liquipi"'! witli \^ 



-.■r- ~ .-^^'i'r'<-<-fitirt^ri-^-^i'jtr'rx.^r^-€-<^-t^.-^-r^y^^ 

^gc n occooc oo coQgafloa fg Moooa K iaa n 

The S perry 



In Venice, graceful Gondolas take the place of cabs 

mywi.ocgt a ».Tinpr 

rr^^^t.^rr^^^,-^^,,,-.-..-cc^'r^^-ef^^^.-^r^^^ " ' ' " ''' ^^' ^ ^ 


J SaX t X^KSU 1X»3JMO Ct. tT >-^ -- J.^.:u. -^ 

The S perry 




mac-v ;^.f.^wy). %.Yii fvy r^rttr^ 

St«3uo-yaefaiiDg is the most coetly of all sports 



iiaccococctn::^-- ~ 

The Sperry n i 

aa c ca ogyiaaa x 


The Mediterranean Felucca, swift in all weathers 

on Long Run 
Floor Test 

t'i^'. a'.^ \lash-r 

rnpusw's un<lt>r 

^p<x:inl Ma<'hin<' 

1 <>ii.~lnict<.'<l to siiniJule thi- 

(ion of ;i Sliip in a Heavy Sfii 


The S perry 


The Sufamariiw, the unaen toror of the nu 

'**5«^^:^' ^tj; 

Sperry Service 

iiKN a Gyro-Compass is sold the interest of The Sperry Gyroscope 
(>onipany does not cease. Our interest in our customer is only begin- 
ning. An experienced service engineer installs every Sperry Gyro- 
(^.onipass. This engineer is also available to make the first trip with 
the compass in order to assure its proper operation. After instal- 
lation the Sperry Service Engineers are available in every large 
port in the world to come aboard and inspect, clean, repair and over- 
haul 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 reason- 
able 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. 


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 obtain- 
able. 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. 


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 



I .■ (.11 1- 



aBQoccaocc n acc Q O co acflCQO 

The S perry 


a'ny-^'^'i ^^c^--^ -tt^^^^''^^*^^-^'*^^ ■■ ■ 

Hie Sampan shoots the rapids of Japanese rivers 

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. 


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. 

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 Dar- 
danelles. 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 in- 
stall the equipment, our engineer 
remained on board and finished the 
work while the ship was enroute from 
Malta to the Dardanelles. ; .,,iu[);i,-Kic.> on li'stai^' 
MiifhiiKi which sinmlalcs the 
Holl, Pilch iinfiYawof ShipatS<'a 


=t\vrx-i^x-rr^^'^''y^''^'''^ i. 

■n-'tirf **'**'^''^ 


- CTHfJT l 'a jJM 

The WluUe-liadi, itMdkst of all ia rough wottlier 

Tliis 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 efTecls 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 w ho 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 Sperr\- 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 

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 saiUng until the 
ship could be swung and the 
magnetic compasses compensated. 
It was decided, however, that al- 
though 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 destrov the British 


in those waters. 


The S perry 

■■.^.t ^ 1 iTvm.i.i.-i.-.i.t-^7^-5-t^,y-. 

r*yTVsa>.^^^^^ ^"^^'*''^'*^«^*^''^''^'''*'^'*^^^"'^ 


yvKT^r-> 7l, •^^TIV^^^ll^^Ty^>| l T»^'^^ i V>y» ^ ^^» ■ ' - 

The Coracle of ancimt Britun, still aged in Walea 

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. 
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 compart- 
ment. 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-Com- 
pass. Every one of 
them performed per- 
fectly throughout the 
action except in the 
case of the Lion on 
which one was des- 
troyed by fire. 

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


The S perry 


iTcrmn i v\m • ittmn 1 1 1 nvfm aat 

The Power Boat, siiiull, able, reJial 

Stn.- I 


The S perry 

Mi.!l.,T. Jr. 

.,-,s£a^ttvvi _ 


^ JC'CHXVggvvv^r.ry>T^■lrt^vr^-r^<Of*^v^t^,w^^^ 

Huge Dug-Outs are used on African rivers 

Ships Rquipi" 

Xtir^-r^--t ^vx-x^f-*Y^r-f-<W,!-*'^^Ty'lf^^ y.-.-f 


The S perry 


^ji^lpfyMfv^-CTNTnivs^M^x t^WTTi?^' 


'"^'^^ ■* gy «^ "M f y ffwy^BfOtiet^ffe^fttnfeayrv^' <fr^^ 

Great ColUerB carry coal for the world's navies 


The S perry 


%»eedy loe-boats provic^ thrilling winter sport 


Telegrams /'"land. SP 
o \ Foreign: 9P 

ERIGYCO. Vic. London 
gn: aPERIQYCO. London. 

Telephone, 73S8 VICTORIA. 






LONDON, 8. W. 

August 1st. 1916. 


The Sperry Gyroscope Company, 

Gentlemen , 

It gives me very great pleasure to inform you that my 
Company has received from Their Lords Commissi oner a of the Admiralty, 
under date 20th July, the tollowlnK words of commendatlon:- 

"I am to add an expression of Their Lordships' appreciation 
of the valuable assistance renderi'd to the Admiralty by 
your Company since the outbri'ak of War, In your very prompt 
and efficient execution of the Important work entrusted to 
you" . 

I might mention that this was the first reoomrtendatlon gl^^■n 

to a private Firm by the British Admiralty for fifteen years, and had 

to be concurred In bj- no less than thirty-seven Government Officials. 

Very truly yours, 


Managing Director.