ELECTRICITY IN WAR
One of the most striking features of modern naval warfare is the
absolute revolution in methods of communication brought about
by wireless telegraphy. To-day every warship has its wireless
installation. Our cruiser squadrons and destroyer flotillas,
ceaselessly patrolling the waters of the North Sea, are always in touch
with the Admiral of the Fleet, and with the Admiralty at Whitehall. In
the Atlantic, and in the Pacific too, our cruisers, whether engaged in
hunting down the marauding cruisers of the enemy or in searching for
merchant ships laden with contraband, have their comings and goings
directed by wireless. Even before the actual declaration of war between
Great Britain and Germany wireless telegraphy began its work. At the
conclusion of the great naval review of July 1914, the Fleet left
Portland to disperse as customary for manœuvre leave, but a wireless
message was dispatched ordering the Fleet not to disperse. As no state
of war then existed, this was a precautionary measure, but subsequent
events quickly proved how urgently necessary it had been to keep the
Fleet in battle array. Immediately war was declared Great Britain was
able to put into the North Sea a fleet which hopelessly outnumbered and
outclassed the German battle fleet.
At the outset Germany had a number of cruisers in the Atlantic and the
Pacific Oceans. Owing to the vigilance of our warships these vessels
were unable to join the German Home Fleet, and they immediately adopted
the rôle of commerce destroyers. In this work they made extensive use
of wireless telegraphy to ascertain the whereabouts of British merchant
ships, and for a short time they played quite a merry game. Prominent
among these raiders was the _Emden_. It was really astonishing how this
cruiser obtained information regarding the sailings of British ships.
It is said that on one occasion she called up by wireless a merchant
ship, and inquired if the latter had seen anything of a German cruiser.
The unsuspecting merchantman replied that there was no such thing as
a German warship in the vicinity. “Oh yes, there is,” returned the
_Emden_; “I’m it!” and shortly afterwards she appeared on the horizon,
to the great discomfiture of the British skipper. An interesting
account of the escape of a British liner from another notorious raider,
the _Karlsruhe_, has been given in the _Nautical Magazine_. The writer
says:
“I have just returned home after a voyage to South America in one
of the Pacific Steam Navigation Company’s cargo boats. When we left
Montevideo we heard that France and Germany were at war, and that
there was every possibility of Great Britain sending an ultimatum to
Germany. We saw several steamers after leaving the port, but could get
no information, as few of them were fitted with wireless and passed
at some distance off. When about 200 miles east of Rio, our wireless
operator overheard some conversation between the German cruiser
_Karlsruhe_ and a German merchant ship at anchor in Rio. It was clearly
evident that the German merchant ship had no special code, as the
conversation was carried on in plain German language, and our operator,
who, by the way, was master of several languages, was able to interpret
these messages without the slightest difficulty. It was then that we
learned that Great Britain was at war. The German cruiser was inquiring
from the German merchant ship what British vessels were leaving Rio,
and asking for any information which might be of use. We also picked up
some news of German victories in Belgium, which were given out by the
German merchant ship. It was clearly evident that the _Karlsruhe_ had
information about our ship, and expected us to be in the position she
anticipated, for she sent out a signal to us in English, asking us for
our latitude and longitude. This our operator, under the instructions
of the captain, declined to give. The German operator evidently got
furious, as he called us an English ‘swine-hound,’ and said, ‘This is a
German warship, _Karlsruhe_; we will you find.’ Undoubtedly he thought
he was going to strike terror to our hearts, but he made a mistake.
“That night we steamed along without lights, and we knew from the sound
of the wireless signals that were being flashed out from the German
ship that we were getting nearer and nearer to her. Fortunately for
us, about midnight a thick misty rain set in and we passed the German
steamer, and so escaped. Our operator said that we could not have
been more than 8 or 10 miles away when we passed abeam. Undoubtedly
our wireless on this occasion saved us from the danger from which we
escaped.”
Apparently little is known of the end of the _Karlsruhe_, but the
_Emden_ met with the fate she richly deserved; and fittingly enough,
wireless telegraphy, which had enabled her to carry out her marauding
exploits, was the means of bringing her to her doom. On 9th November
1914 the _Emden_ anchored off the Cocos-Keeling Islands, a group of
coral islets in the Indian Ocean, and landed a party of three officers
and forty men to cut the cable and destroy the wireless station.
Before the Germans could get to the station, a wireless message was
sent out stating the presence of the enemy warship, and this call was
received by the Australian cruisers _Melbourne_ and _Sydney_. These
vessels, which were then only some 50 miles away, were engaged, along
with a Japanese cruiser, in escorting transports. The _Sydney_ at once
went off at full speed, caught the _Emden_, and sent her to the bottom
after a short but sharp engagement. As the _Emden_ fled at sight of the
Australian warship, the landing party had not time to get aboard, and
consequently were left behind. They seized an old schooner, provisioned
her, and set sail, but what became of them is not known.
In land warfare field telegraphs play a very important part; indeed
it is certain that without them the vast military operations of the
present war could not be carried on. The General Headquarters of
our army in France is in telegraphic communication not only with
neighbouring French towns, but also with Paris and London. From
Headquarters also run wires to every point of the firing-line, so that
the Headquarters Staff, and through them the War Office in London,
know exactly what is taking place along the whole front. The following
extract from a letter from an officer, published by _The Times_, gives
a remarkably good idea of the work of the signal companies of the Royal
Engineers.
“As the tide of battle turns this way and the other, and headquarters
are constantly moving, some means have to be provided to keep in
constant touch with General Headquarters during the movement. This
emergency is met by cable detachments. Each detachment consists of two
cable waggons, which usually work in conjunction with one another, one
section laying the line whilst the other remains behind to reel up when
the line is finished with. A division is ordered to move quickly to
a more tactical position. The end of the cable is connected with the
permanent line, which communicates to Army Headquarters, and the cable
detachment moves off at the trot; across country, along roads, through
villages, and past columns of troops, the white and blue badge of the
signal service clears the way. Behind the waggon rides a horseman,
who deftly lays the cable in the ditches and hedges out of danger
from heavy transport and the feet of tramping infantry, with the aid
of a crookstick. Other horsemen are in the rear tying back and making
the line safe. On the box of the waggon sits a telegraphist, who is
constantly in touch with headquarters as the cable runs swiftly out. An
orderly dashes up with an important message; the waggon is stopped, the
message dispatched, and on they go again.”
Wireless telegraphy too has its part to play in land war, and for
field purposes it has certain advantages over telegraphy with wires.
Ordinary telegraphic communication is liable to be interrupted by the
cutting of the wire by the enemy, or, in spite of every care in laying,
by the breaking of the wire by passing cavalry or artillery. No such
trouble can occur with wireless telegraphy, and if it becomes necessary
to move a wireless station with great rapidity, as for instance on an
unexpected advance of the enemy, it is an advantage to have no wire to
bother about. The Marconi portable wireless sets for military purposes
are marvels of compactness and lightness, combined with simplicity.
They are of two kinds, pack-saddle sets and cart sets. The former weigh
about 360 lb., this being divided amongst four horses. They can be
set up in ten minutes by five or six men, and require only two men to
work them. Their guaranteed range is 40 miles, but they are capable
of transmitting twice this distance or even more under favourable
conditions. The cart sets can be set up in twenty minutes by seven or
eight men, and they have a guaranteed range of from 150 to 200 miles.
It is obviously very important that wireless military messages should
not be intercepted and read by the enemy, and the method of avoiding
danger of this kind adopted with the Marconi field stations is
ingenious and effective. The transmitter and the receiver are arranged
to work on three different fixed wave-lengths, the change from one to
another being effected quickly by the movement of a three-position
switch. By this means the transmitting operator sends three or four
words on one wave-length, then changes to another, transmits a few
words on this, changes the wave-length again, and so on. Each change
is accompanied by the sending of a code letter which informs the
receiving operator to which wave-length the transmitter is passing. The
receiving operator adjusts his switch accordingly, and so he hears the
whole message without interruption, the change from one wave-length to
another taking only a small fraction of a second. An enemy operator
might manage to adjust his wave-length so as to hear two or three
words, but the sudden change of wave-length would throw him out of
tune, and by the time he had found the new wave-length this would have
changed again. Thus he would hear at most only a few disconnected words
at intervals, and he would not be able to make head or tail of the
message. To provide against the possibility of the three wave-lengths
being measured and prepared for, these fixed lengths themselves can be
changed, if necessary, many times a day, so that the enemy operators
would never know beforehand which three were to be used.
Wireless telegraphy was systematically employed in land warfare for the
first time in the Balkan War, during which it proved most useful both
to the Allies and to the Turks. One of the most interesting features
of the war was the way in which wireless communication was kept up
between the beleaguered city of Adrianople and the Turkish capital.
Some time before war broke out the Turkish Government sent a portable
Marconi wireless set to Adrianople, and this was set up at a little
distance from the city. When war was declared the apparatus was brought
inside the city walls and erected upon a small hill. Then came the
siege. For 153 days Shukri Pasha kept the Turkish flag flying, but the
stubborn defence was broken down in the end through hunger and disease.
All through these weary days the little wireless set did its duty
unfalteringly, and by its aid regular communication was maintained with
the Government station at Ok Meidan, just outside Constantinople, 130
miles away. Altogether about half a million words were transmitted from
Adrianople to the Turkish capital.
[Illustration: PLATE XVI.
(_a_) CAVALRY PORTABLE WIRELESS CART SET.]
[Illustration:
_By permission of_ _Marconi Co. Ltd._
(_b_) AEROPLANE FITTED WITH WIRELESS TELEGRAPHY.]
The rapid development of aviation during the past few years has drawn
attention to the necessity for some means of communication between
the land and airships and aeroplanes in flight. At first sight it
might appear that wireless telegraphy could be used for this purpose
without any trouble, but experience has shown that there are certain
difficulties in the way, especially with regard to aeroplanes. The
chief difficulty with aeroplanes lies in the aerial. This must take the
form either of a long trailing wire or of fixed wires running between
the planes and the tail. A trailing wire is open to the objection
that it is liable to get mixed up with the propeller, besides which
it appears likely to hamper to some slight extent the movements of
a small and light machine. A fixed aerial between planes and tail
avoids these difficulties, but on the other hand its wave-length is
bound to be inconveniently small. The heavy and powerful British
military aeroplanes apparently use a trailing wire of moderate length,
carried in a special manner so as to clear the propeller, but few
details are available at present. A further trouble with aeroplanes
lies in the tremendous noise made by the engine, which frequently
makes it quite impossible to hear incoming signals; and the only way
of getting over this difficulty appears to be for the operator to wear
some sort of sound-proof head-gear. Signals have been transmitted
from an aeroplane in flight up to distances of 40 or 50 miles quite
successfully, but the reception of signals by aeroplanes is not so
satisfactory, except for comparatively short distances. Although few
particulars have been published regarding the work of the British
aeroplanes in France, it seems evident that wireless telegraphy is
in regular use. In addition to their value as scouts, our aeroplanes
appear to be extremely useful for the direction of heavy artillery
fire, using wireless to tell the gunners where each shell falls, until
the exact range is obtained. In the case of airships the problem of
wireless communication is much simpler. A trailing wire presents no
difficulties, and on account of their great size much more powerful
sets of apparatus can be carried. The huge German Zeppelin airships
have a long freely-floating aerial consisting of a wire which can
be wound in or let out as required, its full length being about 750
feet. The total weight of the apparatus is nearly 300 lb., and the
transmitting range is said to be from about 120 to 200 miles.
Electricity is used in the navy for a great variety of purposes
besides telegraphy. Our battleships are lighted by electricity,
which is generated at a standard pressure of 220 volts. This
current is transformed down for the searchlights, and also for the
intricate systems of telephone, alarm, and firing circuits. The
magazines containing the deadly cordite are maintained at a constant
temperature of 70° F. by special refrigerating machinery driven by
electricity, and the numerous fans for ventilating the different
parts of the ship are also electrically driven. Electric power is
used for capstans, coaling winches, sounding machines, lifts, pumps,
whether for drainage, fire extinction, or raising fresh water from the
tanks, and for the mechanism for operating boats and torpedo nets.
The mechanism for manipulating the great guns and their ammunition
is hydraulic. Electricity was tried for this purpose on the battle
cruiser _Invincible_, but was abandoned in favour of hydraulic power.
But though electricity is apparently out of favour in this department,
it takes an extremely important share in the work of controlling and
firing the guns; its duties being such as could not be carried out by
hydraulic power.
The guns are controlled and fired from what is known as the
fire-control room, which is situated in the interior of the ship,
quite away from the guns themselves. The range-finder, from his perch
up in the gigantic mast, watches an enemy warship as she looms on the
horizon, and when she comes within range he estimates her distance by
means of instruments of wonderful precision. He then telephones to the
fire-control room, giving this distance, and also the enemy’s speed
and course. The officer in charge of the fire-control room calculates
the elevation of the gun required for this distance, and decides upon
the instant at which the gun must be fired. A telephoned order goes to
the gun-turret, and the guns are brought to bear upon the enemy, laid
at the required elevation, and sighted. At the correct instant the
fire-control officer switches on an electric current to the gun, which
fires a small quantity of highly explosive material, and this in turn
fires the main charge of cordite. The effect of the shell is watched
intently from the fire-control top, up above the range-finder, and
if, as is very likely, this first shell falls short of, or overshoots
the mark, an estimate of the amount of error is communicated to the
fire-control room. Due corrections are then made, the gun is laid at a
slightly different elevation, and this time the shell finds its mark
with unerring accuracy.
The range of movement, horizontal and vertical, of modern naval guns
is so great that it is possible for two guns to be in such relative
positions that the firing of one would damage the other. To guard
against a disaster of this kind fixed stops are used, supplemented by
ingenious automatic alarms. The alarm begins to sound as soon as any
gun passes into a position in which it could damage another gun, and it
goes on sounding until the latter gun is moved out of the danger line.
Since the outbreak of war the subject of submarine mines has been
brought to our notice in very forcible fashion. Contrary to the general
impression, the explosive submarine mine is not a recent introduction.
It is difficult to say exactly when mines were first brought into
use, but at any rate we know that they were employed by Russia during
the Crimean War, apparently with little success. The first really
successful use of mines occurred in the American Civil War, when the
Confederates sank a number of vessels by means of them. This practical
demonstration of their possibilities did not pass unnoticed by European
nations, and in the Franco-German War we find that mines were used
for harbour defence by both belligerents. It is doubtful whether
either nation derived much benefit from its mines, and indeed as the
war progressed Germany found that the principal result of her mining
operations was to render her harbours difficult and dangerous to her
own shipping. Much greater success attended the use of mines in the
Russo-Japanese War, but all previous records shrink into insignificance
when compared with the destruction wrought by mines in the present
great conflict.
Submarine mines may be divided into two classes; those for harbour
defence, and those for use in the open sea. Harbour defence mines are
almost invariably electrically controlled; that is, they are connected
with the shore by means of a cable, and fired by an electric impulse
sent along that cable. In one system of control the moment of firing
is determined entirely by observers on shore, who, aided by special
optical instruments, are able to tell exactly when a vessel is above
any particular mine. The actual firing is carried out by depressing a
key which completes an electric circuit, thus sending a current along
the cable to actuate the exploding mechanism inside the mine. A hostile
ship therefore would be blown up on arriving at the critical position,
while a friendly vessel would be allowed to pass on in safety. In
this system of control there is no contact between the vessel and the
mine, the latter being well submerged or resting on the sea floor,
so that the harbour is not obstructed in any way. This is a great
advantage, but against it must be set possible failure of the defence
at a critical moment owing to thick weather, which of course interferes
seriously with the careful observation of the mine field necessary for
accurate timing of the explosions. This difficulty may be surmounted
by a contact system of firing. In this case the mines are placed so
near the surface as to make contact with vessels passing over them. The
observers on shore are informed of the contact by means of an electric
impulse automatically transmitted along the cable, so that they are
independent of continuous visual observation of the mined area. As in
the previous system, the observers give the actual firing impulse.
The drawback to this method is the necessity for special pilotage
arrangements for friendly ships in order to avoid unnecessary striking
of the mines, which are liable to have their mechanism deranged by
constant blows. If the harbour or channel can be closed entirely to
friendly shipping, the observers may be dispensed with, their place
being taken by automatic electric apparatus which fires at once any
mine struck by a vessel.
Shore-controlled mines are excellent for harbour defence, and
a carefully distributed mine-field, backed by heavy fort guns,
presents to hostile vessels a barrier which may be regarded as almost
impenetrable. A strong fleet might conceivably force its way through,
but in so doing it would sustain tremendous losses; and as these losses
would be quite out of proportion to any probable gains, such an attempt
is not likely to be made except as a last resort.
For use in the open sea a different type of mine is required. This must
be quite self-contained and automatic in action, exploding when struck
by a passing vessel. The exploding mechanism may take different forms.
The blow given by a ship may be made to withdraw a pin, thus releasing
a sort of plunger, which, actuated by a powerful spring, detonates
the charge. A similar result is obtained by the use of a suspended
weight, in place of plunger and spring. Still another form of mine
is fired electrically by means of a battery, the circuit of which is
closed automatically by the percussion. Deep-sea mines may be anchored
or floating free. Free mines are particularly dangerous on account of
the impossibility of knowing where they may be at any given moment.
They are liable to drift for considerable distances, and to pass into
neutral seas; and to safeguard neutral shipping international rules
require them to have some sort of clockwork mechanism which renders
them harmless after a period of one hour. It is quite certain that
some, at least, of the German free mines have no such mechanism, so
that neutral shipping is greatly endangered.
Submarine mines are known as _ground_ mines, or _buoyant_ mines,
according to whether they rest on the sea bottom or float below the
surface. Ground mines are generally made in the form of a cylinder,
buoyant mines being usually spherical. The cases are made of steel,
and buoyancy is given when required by enclosing air spaces. Open-sea
mines are laid by special vessels, mostly old cruisers. The stern of
these ships is partly cut away, and the mines are run along rails
to the stern, and so overboard. The explosive employed is generally
gun-cotton, fired by a detonator, charges up to 500 lb. or more being
used, according to the depth of submersion and the horizontal distance
at which the mine is desired to be effective. Ground mines can be used
only in shallow water, and even then they require a heavier charge
than mines floating near the surface. Mines must not be laid too close
together, as the explosion of one might damage others. The distance
apart at which they are placed depends upon the amount of charge,
500-lb. mines requiring to be about 300 feet apart for safety.