THE SUN, SUNDAY, FEBRUARY 24, 1918.
Submarine, Hard to Make, Easy to Break
By A. M. JUNCMANN,
Associate Editor of the "Popular Science
Monthly."
EVEK since the first torpedo launched
by a submarine sent its victims to
a watery grave inventors have busied
themselves with means of combating this
Eca menace.
In order to understand the problems
which beset the inventors of anti-submarine
devices one must know something
if the construction of the submarine and
its method of attack.
Submarines arc built with two hulls.
The inner hull is intended to withstand
the water pressure when submerged and
is stronger than the outer. The two
hulls are connected by stout braces so
that the outer hull and the braces arc a
protection against the tremendous pres
sure the submarine lias to stand when
beneath the surface.
Oil Carried in Hull.
The space between the hulls is divided
into compartments which are used for
carrying oil for fuel and other compart
ments which arc used for the water bal
last the submarine must take on in order
to submerge. When the submarine is
ready to dive, water is admitted to these,
compartments; when the vessel rises to
the surface the water is forced out of the
compartments.
In attacking a submarine it is neces
sary to do more than damage the outer
hull. The patches of oil which are fre
quently seen floating on the water after
a submarine lias been attacked arc not
by any means a sure indication that the
Kaiser's sea monster has been sent to the
bottom. In order to destroy a submarine
by shell fire both hulls must be pierced.
Rut the German submarine has its
Achilles heel in the horizontal rudders
which it carries both forward and aft.
Once either of these two pairs of rudders
is damaged the submarine cannot main
tain its chosen depth. It must cither sink
to the bottom and if in water more than
200 feet deep such a sinking would be
fatal or it must rise to the surface and
subject itself to the enemy fire.
Storage Batteries a Danger.
A very great source of danger to a sub
marine which is attacked by bombs or
shells is the storage batteries necessary
foi supplying the electric power by which
it must travel when submerged. It is
quite possible that a shock caused by a
heavy explosion may destroy the storage
batteries and release aa acid which will
eat its way through the metal of the hull.
The moment this acid comes into con
tact with the sea water a deadly gas is
foiined and the crew must die the same
horrible death that Germany has been
inflicting on her enemies by using poison
gas on the battlefields. Other weak
iots on submarines are the periscopes,
conning towers and screws.
Curiouhly enough the U-boat can be
most successfully hunted from the skies.
Jf the weather is clear and the sea is calm
ar aviator will be able to detect a peri
scope from a height of several hundred
ft-et much more easily than it could be
seen from a position near the surface.
Periscopes are so small and nowadays so
well camouflaged that it is difficult to de
tect them from a boat. But to the eyes
of an aviator they stand out prominently
against the sea water.
What the "Blimps" Do.
The airman is assisted in his search for
concealed U-boats by special optical in
struments which not only increase his
range of vision, just as your vision would
be aided by looking through a pair of
binoculars, but are adapted to aid in see
ing beneath the water.
Where the water is unusually clear an
airman flying at an altitude of from 1,000
to 2,000 feet can detect a submarine which
is submerged to a depth of 100 feet. This,
it must be borne in mind, is only possible
under the most favorable conditions. If
the water is rough or not clear or if the
weather is unfavorable it is quite impos
sible to detect the submarine.
One of the reasons why it is possible for
a seaplane to bomb a submarine is that it
ran approach its prey without making its
presence known by the noise of its engine.
This is possible because the lapping of the
waves and the sound of the wind drown
the noise of the seaplane's engine.
The ''blimps" of the British have been
ciy successful in hunting submarines.
They are a cross between an airplane and
a dirigible. They have an airplane body
and power plant and arc b'ke the dirigible
inasmuch as they carry a gas bag.
This dirigible feature-WjftleVfliem'lb11
One Set of Men Devote Energies to Devel
oping Submersibles, Another to Destroy
ing Them The Dangers of the Deep
stop and investigate anything they sec
which is suspicious. An ordinary airplane
cannot do this; it miist always fly at a
high rate of speed. The blimps are
equipped with bombing devices and wire
less. They make excellent coast patrols.
There have been literally thousands and
thousands of plans for combating the
U-boat. Many of these inventions have
been misgaided efforts of well meaning
but ignorant persons. That is to say,
persons who are ignorant of ordinary
mechanical principles.
For example, take the innumerable de
vices which employ electro magnets and
magnetism as the basis of a plan for anni
hilating the submarine. Many men seem
to think that if ships equipped with mag
nets arc sent out they can draw a sub
marine fmm its course just as the small
tanee of from twenty to thirty feet away
from the side of the vessel.
If a ship is lying in a harbor it is an
easy matter to protect her with such a
net. Hut if she is steaming through a
heavy sea, the tremendous weight of the
water dashing against the nets would de
stroy them. Even under ideal conditions
dragging heavy nets would cut down the
speed of any vessel to about five or six
knots.
Another system somewhat similar to the
use of nets is that of towing steel plates
on each side of the vessel. It is said that
none of these suggestions has been ap
proval by the Navy D partmcnt.
One of the surest protections against
the deadly torpedo is to divide the hull
of a vessel into many compartments.
The hull is divided into a great many
Vs
r-
U.S. SUBMARINE STEAMING
SURFACE SPEED.
aV FULL.
boy picks up a needle with the pocket
magnet. Perhaps the reason this impres
sion is so general is that magnets have
been successfully used in manufacturing
plants for lifting masses of iron or steel.
They forget that the magnet must be
placed in contact with the mass of metal
before it can lift it
It is absurd to suppose that a magnet
can deflect a torpedo which weighs be
tween two and three thousand pounds and
is tearing through the water at a rate of
some forty miles an hour.
Many inventors seem to think that it
is possible to send forth a sort of electro
cuting current through the water. Others
have planned means of shooting forth
electric bombs, and innumerable inven
tors believe that it is possible to electrify
the water or the atmosphere in such a
way that submarines would be destroyed.
Such ideas arc utterly impracticable.
But electricity in combating the subma
rine is invaluable for sending signals and
messages. Clever inventors are con
stantly -working along these lines, and
each day conceive an improvement in the
use- of electricity for this purpose.
Ever so many devices have been sug
gested which are intended to protect cargo
carrying ships by means of nets or
screens. These generally arc very unsat
isfactory. In order to be of protection
?lo the'-Ship' tnef-'nnW-T'neld'at acHs-
compartmenls. If a torpdo manages to
puncture one of these compartments those
adjoining it are immediately filled with
compressed air, so that the water pressure
is equalized and no more can enter. An
advantage possessed by the Wotherspoon
system is that it necessitates very little
change in the design of the vessel. Bat
tleships have always been built with hulls
divided into many compartments in order
to protect them from taking in too much
water in case of a collision.
As compressed air is used on battleships
to run the refrigerating machines, to fire
and charge the torpedoes and to remove
the hot gases from the gun barrels after
firing, the installation of the Wotherspoon
method was a very simple thing. All that
had to be done was to connect the com
pressed air supply with the compart
ment pipes. It was not necessary to
change the design of tbe inner hull.
One interesting solution of the sub
marine problem consists of a scries of
buoys which are large enough to accom
modate four men and afford-ihem living
quarters for days at a time. The buoys
have a three inch rapid fire gun mounted
on the upper deck". Beneath the gun
deck are the living quarters for the crew
and below that is a tank which can be
filled with water ballast when the buoy is
to be sunk. At the bottom is a eylindri
'eal ebmptcaxi'tSt'taiii. -' K iwin-i i
The buoy is as large as an ordinary
room, being abrat sixteen feet in diam
eter. Each buoy has telephone connec
tions with the land station, a microphone
for detecting the approach of the sub
marine by the hum of its engine and a
complete wireless outfit. A gasolene en
gine is used to fill Uie compressed air tank.
The buoys are to be connected by nets.
If a submarine strikes the net during the
day a flag indicates the fact and at night
an incandescent lamp gives warning of
the enemy's presence.
Duties of tbe Crew.
The duties of the crew are divided.
One man would always be on deck as a
lookout; another would be detailed to
the wireless apparatus; a third would be
ready to perform any duty which might
be necessary in an emergency, and the
fourth man would be sleeping. In that
way three of the four men are always on
duty.
Many interesting sound recording de
vices have been designed with the inten
tion of locating submarines or moving
torpedoes. These electrical ears open up
a big field to the inventor who has sufli
cient scientific training to develop the
subject. Water is a wonderful conductor
of sound and for that reason sound re
cording devices are particularly advanta
geous in eluding the submarine and its
torpedo.
Devices which depend upon optical
means for detecting submarines arc not
likely to lie of ad great assistance as
the sound recording devices. The exhaust
air from its propelling engine causes a
stream of hubbies to appear on the sur
face of the water in tbe wake of a tor
pedo. If the sea is very rough it is
practically impossible to discover these
bubbles.
Before the bubbles are seen the tor
pedo may have travelled anywhere from
fifty to two li'.indr-l feet in the direction
of its target. Therefore, it is a lively
ship which can elude the turpi-do once
it has started on its path.
Fast Ships Immune.
It is a curious fact that ships which
can exceed fifteen knots have suffered
very little from submarine attack. Slow
vessels, on the other hand, have no ehancv
when attacked by a submarine. In order
to be able to evade the submarine, a ves
sel must have a greater speed than thaf
of the submarine when submerged.
The newest (Jcrman submarines are
said to have a submerged sjoel of about
ten knots and a surface sjeed of seven
teen knots per hour. Kccords show that
the slow vessels, once they are singled out
by the submarines for attack, are doomed.
The number of slow vessels which havo
e.scacd is mi small as to lie negligible.
Smoke screens have been found very
useful to vessels which have high speed
ami an' capable of quick manu-uvering.
When the vessel sights the periscope of a
submarine, smoke boxen are got out and
thrown overboard. The boxes are filled
with a substance which whra burning
gives forth a" very dense sniokr. The ves
sel, hidden behind the smoke. screen, can
change her position antl escape tbe tor-.
!edo.'
A Cheerful Sendoff!
DOWN" in south Jersey they are wide
awake. The hour hand of the
Jersey clocks had not gone twice around
the dial after 300 newly drafted men in
a certain city had been called for physi
cal examination when the postman
brought to each of them an invitation to
buy a cemetery lot. The invitation read
as follows:
"Which is the better time to consider
a matter of this character? Now, when
there is ample time for calm, deliberate
selection, or later, perhaps, when there is
a necessity 1 Experience lias proved the
former the better course; there is a
satisfaction in owning an unused plot
and in knowing you have relieved others
of a responsibility."
There arc possibilities for the humorist
in this, if any one feels like getting fun
out of it. Probably it does not seem
funny to the young men about to be
taken from their work and their wonted
ways of daily living to go into the
trenches.
The clerk of the county is going to
investigate the manner in which the
names got out, and it may not be funny
then for the people who sent out these
cheerful invitations.
Somebody ought to investigate, while
investigation is in order, the psychology
'of tbfeSenfr&ffiimf;' sssucL
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