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THE JOURNAL OF SUBMARINE COMMANDER VON FORSTNER
[Illustration: _Copyright by Underwood & Underwood, N.Y._
PASSENGERS AND CREW LEAVING A SINKING LINER TORPEDOED BY A
GERMAN SUBMARINE IN THE MEDITERRANEAN]
THE JOURNAL OF
SUBMARINE COMMANDER
VON FORSTNER
TRANSLATED BY
MRS. RUSSELL CODMAN
WITH AN INTRODUCTION BY
JOHN HAYS HAMMOND, JR.
[Illustration]
BOSTON AND NEW YORK
HOUGHTON MIFFLIN COMPANY
The Riverside Press Cambridge
1917
COPYRIGHT, 1917, BY JOHN HAYS HAMMOND, JR. AND ANNA CRAFTS CODMAN
ALL RIGHTS RESERVED
_Published November 1917_
CONTENTS
FOREWORD BY THE TRANSLATOR vii
INTRODUCTION BY JOHN HAYS HAMMOND, JR.: THE CHALLENGE TO
NAVAL SUPREMACY xi
I. ORDERED TO COMMAND A SUBMARINE 1
II. BREATHING AND LIVING CONDITIONS UNDER WATER 6
III. SUBMERSION AND TORPEDO FIRE 17
IV. MOBILIZATION AND THE BEGINNING OF THE COMMERCIAL WAR 39
V. OUR OWN PART IN THE COMMERCIAL WAR AND OUR FIRST
CAPTURED STEAMER 53
VI. THE CAPTURE OF TWO PRIZE STEAMERS 74
VII. OFF THE COAST OF ENGLAND 97
VIII. THE METHOD OF SINKING AND RAISING SHIPS 122
ILLUSTRATIONS
PASSENGERS AND CREW LEAVING A SINKING LINER
TORPEDOED BY A GERMAN SUBMARINE IN THE
MEDITERRANEAN _Frontispiece_
INTERIOR OF A SUBMARINE xliv
A TORPEDOED SCHOONER 36
GERMAN SUBMARINES U 13, U 5, U 11, U 3, AND U 16 IN KIEL
HARBOR 40
VON FORSTNER'S SUBMARINE (U 28) IN ACTION IN THE NORTH SEA:
A SERIES OF PHOTOGRAPHS TAKEN FROM THE DECK OF ONE OF HER
VICTIMS 78
From the London _Graphic_, March 27, 1915
LIFEBOAT LEAVING THE SINKING P. AND O. LINER ARABIA 98
BRITISH HOSPITAL SHIP GLOUCESTER CASTLE, SHOWING RED CROSS
ON BOW, SUNK IN THE ENGLISH CHANNEL BY A GERMAN SUBMARINE 126
FOREWORD
The following pages form an abridged translation of a book published
in 1916 by Freiherrn von Forstner, commander of the first German
U-boat. It was written with the somewhat careless haste of a man who
took advantage of disconnected moments of leisure, and these moments
were evidently subject to abrupt and prolonged interruptions. Many
repetitions and trivial incidents have been omitted in this
translation; but, in order to express the personality of the Author,
the rendering has been as literal as possible, and it shows the
strange mixture of sentimentality and ferocity peculiar to the
psychology of the Germans.
Part of the book gives a technical description,--not so much of the
construction of a submarine as of the nature of its activities,--which
presents us an unusual opportunity to glean a few valuable facts from
this personal and intimate account of a German U-boat. We are inclined
to a certain grim humor in borrowing the candid information given to
us Americans so unconsciously by Freiherrn von Forstner, for he could
hardly suppose it would fall into the hands of those who would join
the fighting ranks of the _hated enemy_, as, in his bitter animosity,
he invariably calls the English whenever he refers to them.
Several chapters in this book are simple narratives of the commander's
own adventures during the present naval warfare waged against
commerce. His attempts at a lighter vein often provoke a smile at the
quality of his wit, but he is not lacking in fine and manly virtues.
He is a loyal comrade; a good officer concerned for the welfare of his
crew. He is even kindly to his captives when he finds they are docile
victims. He is also willing to credit his adversary with pluck and
courage. He is never sparing of his own person, and shows admirable
endurance under pressure of intense work and great responsibility. He
is full of enthusiastic love for his profession, and in describing a
storm at sea his rather monotonous style of writing suddenly rises to
eloquence. But in his exalted devotion to the Almighty War Lord, and
to the Fatherland, he openly reveals his fanatical joy in the
nefarious work he has to perform.
It is difficult to realize that this ardent worship of detail, and
this marvelous efficiency in the conservation of every resource, are
applied to a weapon of destruction which directs its indiscriminate
attacks against women and children, hospital transports, and relief
ships. Nothing at the present day has aroused such fear as this
invisible enemy, nor has anything outraged the civilized world like
the tragedies caused by the German submarines.
This small volume may offer new suggestions to those familiar with the
science of submarine construction, and it may also shed a little
light, even for lay readers, on a subject which for the last three
years has taken a preëminent place in the history of the War.
INTRODUCTION
THE CHALLENGE TO NAVAL SUPREMACY
I
In a letter to William Pitt, of January 6, 1806, relating to his
invention of a submersible boat, Robert Fulton wrote prophetically,
"Now, in this business, I will not disguise that I have full
confidence in the power which I possess, which is no less than to be
the means, should I think proper, of giving to the world a system
which must of necessity sweep all military marines from the ocean, by
giving the weaker maritime powers advantages over the stronger, which
the stronger cannot prevent."
It is interesting to note that, about a hundred years later,
Vice-Admiral Fournier of the French Navy stated before a Parliamentary
committee of investigation that, if France had possessed a sufficient
number of submersibles, and had disposed them strategically about her
coasts and the coasts of her possessions, these vessels could have
controlled the trade routes of the world. He said also that the
fighting value of a sufficient number of submersibles would
reëstablish the balance of power between England and France.
The history of naval warfare during the last few months has confirmed
the opinions of these two authorities, although in a manner which they
in no way anticipated.
Direct comparison is the usual method by which the human mind
estimates values. We would measure the strength of two men by pitting
them against each other in physical encounter; in the same way, we are
prone to measure the combative effect of weapons by pitting them in
conflict against other weapons. But modern warfare is of so complex a
nature that direct comparisons fail, and only a careful analysis of
military experience determines the potentiality of a weapon and its
influence on warfare. Robert Fulton and Admiral Fournier both
indicated that they believed in the submersible's supremacy in actual
encounter with capital ships. The war, so far, has shown that, in
action between fleets, the submersible has played a negative part. In
the Jutland Bank battle, the submersible, handicapped in speed and
eyesight, took as active a part, as a Jack Tar humorously put it, "as
a turtle might in a cat fight." Not even under the extraordinary
conditions of the bombardment in the Dardanelles, when the
circumstances were such as lent themselves strikingly to submarine
attack, did these vessels score against the fleet in action.[1]
It is easy to understand why the submersible did not take a vital part
in any of the major naval actions. In the naval battle of to-day we
have a number of very high-speed armored craft fighting against one
another over ranges extending up to 17,000 yards. There is a constant
evolution in the position of the ships which it is impossible to
follow from the low point of vantage of a periscope, for the
different formations of ships mean nothing to the submersible
commander. He is so placed that his range of vision is extremely
limited, and, on account of the low speed of his boat while submerged,
he can operate over only a very limited area of water while the other
vessels are moving many miles. Then, too, he is extremely vulnerable
to the effect of enemy shells and to the ramming of enemy ships. Under
these conditions the submersible commander is more or less forced to a
policy of lying ambushed to surprise his enemy. It is said that the
"Lusitania" was decoyed into a nest of submersibles. There was but
little chance of torpedoing her in any other way. There is also the
statement that Admiral Beatty passed with his battle-cruisers through
a flotilla of enemy submersibles without being touched.
Submersibles cannot attack their target in definite formations as do
surface vessels, and therefore they cannot operate in numbers with the
same effectiveness as do the latter. They must maneuver more or less
singly, and at random. Being limited to the torpedo, which, when they
are submerged, is their sole weapon of attack, they have an uncertain
means of striking their armed enemy. The eccentricities of the
automobile torpedo are well known; but, even eliminating the fact that
this missile is unreliable, the important question of accuracy in the
estimate of range and speed which the submersible commander has to
make before firing the torpedo must be considered. There is usually a
large percentage of error in his calculations unless the submersible
is extremely close to its target. Realizing these limitations, the
German submersibles are equipped with small torpedoes, which are
generally fired at ranges not exceeding eight hundred to two thousand
yards. The necessity of approaching the target so closely is, of
course, a tremendous handicap in the general operation of these boats.
In view of these facts, it is not surprising that the submersible
should not have been able to sweep the capital ship from the seas, as
was predicted by certain experts before the war.
II
Admiral Sir Cyprian Bridge regards the functions of defense by a navy
as divisible into three main classifications. He says, "The
above-mentioned three divisions are called in common speech, coast
defense, colonial defense, and defense of commerce." From this
classification we are given a hint as to what a sailor means by "naval
supremacy," "freedom of the seas," and other terms so misused that
to-day they mean nothing. "Coast defense" means defense against
invasion; "colonial defense" means the safeguarding of distant
possessions against enemy forces; the "defense of commerce" means such
supremacy on the seas as will insure absolute safety of the mercantile
marine from enemy commerce-destroyers.
To-day every great nation is waging a trade war. The industrial
competition of peace is as keen as the competition of war. All the
great Powers realized years ago that, to gain and keep their "place in
the sun," it was necessary for them to construct navies that would
insure to them a certain control of the seas for the protection of
their commerce. In this way began the abnormal naval construction in
which the Powers have vied with one another for supremacy.
A simple way of looking at the question, what constitutes the power of
a fleet, is to consider the warship as merely a floating gun-platform.
Even though this floating platform is the most complex piece of
mechanism that was ever contrived by man, nevertheless its general
function is simple. The war has given us enough experience to convince
us that the backbone of a navy is, after all, the heavily armored
ship of moderately high speed, carrying a very heavy armament. This
floating gun-platform is the structure best fitted to carry large guns
into battle, and to withstand the terrific punishment of the enemy's
fire.
The battleship is to-day, notwithstanding the development of other
types, queen of the seas. It is therefore not difficult to estimate
the relative power of the fleets of different nations. In fact, a
purely engineering estimate of this kind can be made, and the
respective ranks of the world's naval powers ascertained. Germany has
shown all through the war that she thoroughly appreciated the British
naval supremacy. Her fleet has ventured little more than sporadic
operations from the well-fortified bases behind Heligoland. It was
probably the pressure of public opinion, and not the expectation
that she would achieve anything of military advantage, that forced her
to send her high-sea fleet into conflict with the British squadrons
off Jutland.
If one should examine the course of this battle, which has been
represented by lines graphically showing the paths of the British and
German fleets, one could easily see how the British imposed their will
upon the Germans in every turn that these lines make. It reminds one
very much of the herding of sheep, for the German fleet was literally
herded on May 31, 1916, from 5:36 in the afternoon until 9 o'clock
that night. Admiral von Scheer, however, fought the only action which
it was possible for him to fight. It was a losing action, and one
which he knew, from a purely mathematical consideration, could not be
successful.
Through the very definiteness of this understanding of what
constitutes naval strength, Great Britain's navy until recently has
remained a great potential force, becoming dynamic for only a few
hours at Jutland, after which it returned to that mysterious northern
base whence it seems to dominate the seas. Because of the potentiality
of these hidden warships, thousands of vessels have traversed the
ocean, freighted with countless tons of cargoes and millions of men
for the Allies. Even at that psychological moment when the first
hundred thousand were being transported to France, Germany refrained
from a naval attack which might have turned the whole land campaign in
her favor.
To-day, however, the world is awakening to a new idea of sea-power, to
a new conception that will have a far-reaching influence on the future
development of naval machinery.
Sir Cyprian Bridge has stated that one of the functions of a fleet is
the defense of commerce. There is no more important function for a
fleet than this. A nation may be subjugated by direct invasion, or it
may be isolated from the world by blockade. If the blockade be
sufficiently long, and effectively maintained, it will ruin the nation
as effectually as direct invasion.
Thus, in the maintenance of a nation's merchant marine on the high
seas, its navy exercises one of its most vital functions. There can,
therefore, be no naval supremacy for a nation unless its commerce is
assured of immunity from considerable losses through the attack of its
enemy. It is idle for us to speak of our naval supremacy over Germany,
when our navies are failing in one of their most important functions,
and when our commerce is suffering such serious losses. The persons
best qualified to judge are those who are most anxious regarding the
present losses in mercantile tonnage.
While it has been shown that the submersible of to-day, as a fighting
machine, is considerably limited, and in no sense endangers the
existence of the capital ship, nevertheless in the new huge
submersible it seems that the ideal commerce-destroyer has been found.
This vessel possesses the necessary cruising radius to operate over
sufficient distances to control important routes; it makes a surface
speed great enough to run down cargo steamers, and has a
superstructure to mount guns of considerable power (up to six-inch).
It embodies almost all the qualifications of the light surface
cruiser, with the additional tremendous advantage of being able to
hide by submergence. To be completely successful, it must operate in
flotillas of hundreds in waters that are opaque to aërial observation.
Germany has but a limited number of these submersibles, otherwise she
would be able to crush the Allied commerce.
The ideal submersible commerce-raider should be a vessel of such
displacement that she could carry a sufficient number of large guns in
her superstructure to enable her to fight off the attack of surface
destroyers and the smaller patrol craft.[2] She should be capable of
cruising over a large radius at high speed, both on the surface and
submerged. The supersubmersible flotillas should comprise fifty or
sixty of these units. The attack on the trade routes should be made by
a number of flotillas operating at different points at unexpected
times. To-day Germany has concentrated her submarine war particularly
in the constricted waters about England. It is here that the shipping
is most congested, and therefore the harvest is richest, but it is
also easier to protect the trade routes over these limited areas of
water by patrols, nets, etc., than it would be to protect the entire
trans-oceanic length of the steamship lanes. If the submersible were
capable of dealing directly with the destroyer in gun-fighting, a
tremendous revolution would take place in the tactics of "submarine
swatting." Then it would be difficult to see how the submersible could
be dealt with.
Improvement in motive machinery is the vital necessity in the
development of the submersible. The next few years may see unexpected
strides taken in this direction. A great deal will also be
accomplished in perfecting methods of receiving sounds under water,
particularly in relation to ascertaining the direction of these
sounds. When this is done, it will be possible for the submersible
commander to tell a great deal about the positions of the vessels
above him, and thus his artificial ears will compensate to a great
extent for his blindness. By the addition of a greater number of
torpedo-tubes, and the improvement of their centralized control in the
hand of the commander at the periscope, along lines which we are now
developing, it will be possible for the submersible to achieve a
greater effectiveness in its torpedo fire. Probably torpedoes will
then be used only against the more important enemy units, such as
battleships, cruisers, and the like. To be certain of striking these
valuable targets would be worth expending a number of torpedoes in
salvo fire.
Whether the German U-boat campaign succeeds or not will be largely a
question of the number of submersibles that the Central Powers can put
into service, and to what extent the submersible will be developed
during the present war.
III
German submarines have sunk over 7,250,000 tons of the Allied
shipping. In December, 1916, it was stated in the British Parliament
that the merchant marine of Great Britain had at that time over
20,000,000 tons. Within the first three months of the unrestricted
submarine warfare, 1,100,000 tons of British shipping went to the
bottom. At this rate, England would lose 25 per cent of her merchant
marine per annum. It is for this reason that the attention of the
entire world is concentrated upon the vital problem of the submarine
menace. On land, the Central Powers are still holding their ground,
but there is a continuous increase of the forces of the Allies which
should lead finally to such a preponderance of power as will overwhelm
the forces opposed to them. The Allied armies, however, depend for
their sustenance and supplies upon the freedom of the seas. The trade
routes of the world constitute the arteries which feed the muscles of
these armies. Germany is endeavoring to cut these arteries by the
submarine. Should she even appreciably limit the supplies that cross
the ocean to the Allies, she will bring about a condition that will
make it impossible to augment their armies. In this way there will
inevitably be a deadlock, which, from the German standpoint, would be
a highly desirable consummation.
Obviously, the first method of handling the submarine problem would
be to bottle the German undersea craft in their bases. There has been
a number of proposals as to how best to accomplish this. It has been
stated that the English Navy has planted mines in channels leading
from Zeebrugge and other submarine bases; but it is necessary only to
recall the exploits of the E-11 and the E-14 of the British Navy at
the Dardanelles, to see that it would not be impossible for the
Germans to pass in their U-boats through these mine-fields into the
open sea. It will be remembered that the E-11 and the E-14 passed
through five or more mine-fields, thence through the Dardanelles into
the Sea of Marmora, and even into the Bosphorus under seemingly
impossible conditions. Yet, in spite of the tremendous risks that they
ran, these boats continued their operations for some time, passing up
as far as Constantinople, actually shelling the city, sinking
transports, and accomplishing other feats which have been graphically
described in the stories of Rudyard Kipling. And again, if the
mine-fields were placed in close proximity to their bases, it would be
comparatively easy for German submersibles of the Lake type,
possessing appliances to enable divers to pass outboard when the
vessel is submerged, to go out and cut away the mines and thus render
them ineffective.
Nets are also used to hinder the outward passage of the submarine.
These nets can likewise be attacked and easily cut by devices with
which modern U-boats are equipped. The problem of placing these
obstacles is a difficult one, in view of the fact that the ships so
engaged are harassed by German destroyers and other enemy craft.
Outside of Zeebrugge, shallow water extends to a distance of about
five miles from the coast, and it has been suggested that a large
number of aircraft, carrying bombs and torpedoes, should be used to
patrol systematically the channel leading from that port to deep
water, with the intent of attacking the submersibles as they emerge
from this base. It is ridiculous to suppose that the Germans would not
be able to concentrate an equally large number of aircraft, to be
supported also by anti-aircraft guns on the decks of destroyers and by
the coast defenses. We have not yet won the supremacy of the air, and
it must inevitably be misleading to base any proposition on the
assumption that we are masters of that element.
The problem of bottling up the submersibles is enormously difficult,
because it necessitates operations in the enemy's territory, where he
would possess the superiority of power. I believe that the question of
operations against the submarine bases is not a naval but a military
one, and one which would be best solved by the advance of the Western
left flank of the Allied armies.
The second method is to attack the submarines with every appliance
that science can produce. In order to attack the submarine directly
with any weapon, it is necessary first to locate it. This is a problem
presenting the greatest difficulty, for it is by their elusiveness
that the submarines have gained such importance in their war on
trade. They attack the more or less helpless merchant ships, and
vanish before the armed patrols appear on the scene.
Almost every suitable appliance known to physics has been proposed for
the solution of the problem of submarine location and detection. As
the submarine is a huge vessel built of metal, it might be supposed
that such a contrivance as the Hughes induction balance might be
employed to locate it. The Hughes balance is a device which is
extremely sensitive to the presence of minute metallic masses in
relatively close proximity to certain parts of the apparatus.
Unfortunately, on account of the presence of the saline sea-water, the
submersible is practically shielded by a conducting medium in which
are set up eddy currents. Although the sea-water may lack somewhat in
conductivity, it compensates for this by its volume. For this reason,
the induction balance has proved a failure.
But another method of detecting the position of a metallic mass is by
the use of the magnetometer. This device operates on the principle of
magnetic attraction, and in laboratories on stable foundations it is
extremely sensitive. But the instability of the ship on which it would
be necessary to carry this instrument would render it impossible to
obtain a sufficient degree of sensitiveness in the apparatus to give
it any value. The fact that the submersible is propelled under water
by powerful electric motors begets the idea that the electrical
disturbances therein might be detected by highly sensitive detectors
of feeble electrical oscillations. The sea-water, in this case, will
be found to absorb to a tremendous extent the effects of the
electrical disturbance. Moreover, the metallic hull of the submersible
forms in itself an almost ideal shield to screen the outgoing effect
of these motors.
Considerable and important development has been made in the creation
of sensitive sound-receiving devices, to hear the propeller vibrations
and the mechanical vibrations that are present in a submersible, both
of which are transmitted through the water. There are three principal
obstacles to the successful use of such a device: when the submersible
is submerged, she employs rotary and not reciprocating prime-movers,
being in consequence relatively quiet when running under water, and
inaudible at any considerable distance; the noises of the vessel
carrying the listening devices are difficult to exclude, as are also
the noises of the sea, which are multitudinous; finally, the
sound-receiving instruments are not highly directive, hence are not of
great assistance in determining the position of the object from which
they are receiving sounds.[3]
To locate the submersible, aërial observation has been found useful.
It is particularly so when the waters are clear enough to observe the
vessel when submerged to some depth, but its value is less than might
be supposed in the waters about the British Isles and Northern
Europe, where there is a great deal of matter in suspension which
makes the sea unusually opaque. The submersible, however, when running
along the surface with only its periscope showing, is more easily
detected by aircraft than by a surface vessel. Behind the periscope,
there is a characteristic small wake, which is distinguishable from
above, but practically invisible from a low level of observation. Many
sea-planes are operating on the other side for the purpose of locating
enemy submersibles and reporting their presence to the surface patrol
craft. In order to overcome the disadvantages of creating the
periscope wake which I have mentioned, it is reported that the Germans
have developed special means to allow the U-boats, when raiding, to
submerge to a fixed depth without moving. To maintain any body in a
fluid medium in a static position is a difficult matter, as is shown
in the instability of aircraft. One of the great problems of the
submersible has been to master the difficulties of its control while
maintaining a desired depth. The modern submersible usually forces
itself under water, while still in a slightly buoyant condition, by
its propellers and by the action of two sets of rudders, or
hydroplanes, which are arranged along its superstructure and which
tend to force it below the surface when they are given a certain
inclination; but should the engines stop, the diving rudders, or
hydroplanes, would become ineffective, and, because of the reserve
buoyancy in the hull, the vessel would come to the surface.
In order to maintain the vessel in a state of suspension under water
without moving, it would be necessary to hold an extremely delicate
balance between the weight of the submarine and that of the water
which it displaces. Variations in weights are so important to the
submersible that, as fuel is used, water is allowed to enter certain
tanks to compensate exactly for the loss of the weight of the fuel. To
obtain such an equilibrium, an automatic device controlled by the
pressure of the water, which, of course, varies with the depth, is
used. This device controls the pumps which fill or empty the
ballast-tanks, so as to keep the relation of the submersible to the
water which it displaces constant, under which condition the vessel
maintains a fixed depth. The principle of this mechanism is, of
course, old, and was first embodied in the Whitehead torpedo, which
has a device that can be set so as to maintain the depth at which it
will run practically constant. With the addition of a telescopic
periscope, which can be shortened or extended at will, it will be
possible for the U-boat to lie motionless with only the minute surface
of the periscope revealing her position.
IV
To attack the submersible is a matter of opportunity. It is only when
one is caught operating on the surface, or is forced to the surface by
becoming entangled in nets, that the patrol has the chance to fire
upon it. Against this method of attack, modern submersibles have been
improving their defenses. To-day, they are shielded with armor of
some weight on the superstructure and over part of the hull. They are
also equipped with guns up to five inches in diameter, and, affording,
as they do, a fairly steady base, they can outmatch in gun-play any of
the lighter patrol boats which they may encounter.
One of the important improvements which have been made has resulted in
the increased speed with which they now submerge from the condition of
surface trim. A submersible of a thousand tons displacement will carry
about five hundred tons of water ballast. The problem of submerging is
mainly that of being able rapidly to fill the tanks. On account of the
necessity of dealing with large quantities of water in the ballast
system, the European submersibles are equipped with pumps which can
handle eight tons of water per minute.
Again, the speed which the electrical propulsion system gives the
vessel on the surface greatly increases the pressure which the diving
rudders can exert in forcing the submersible under water. This effect
may be so marked that it becomes excessive, and Sueter emphasizes the
point that vessels at high speed, when moving under water, may, on
account of the momentum attained, submerge to excessive depths. To
eliminate this tendency, there is a hydrostatic safety system which
automatically causes the discharge of water from the ballast-tank when
dangerous pressures are reached, thus bringing the submersible to a
higher level where the pressure on the hull will not be so severe.
From this it follows that the opportunity of ramming a submersible,
or of sinking it by gunfire, is greatly minimized, since the vessel
can disappear so rapidly.
[Illustration: _Photograph from Underwood & Underwood, N.Y._
INTERIOR OF A SUBMARINE]
A great deal has been attempted with nets. Fixed nets extend across
many of the bodies of water around the British Isles. Their positions,
doubtless, are now very well known to the Germans. The problem of
cutting through them is not a difficult one. Moreover, the hull of the
submersible has been modified so that the propellers are almost
entirely shielded and incased in such a way that they will not foul
the lines of a net. There has also been a steel hawser strung from the
bow across the highest point of the vessel to the stern, so that the
submersible can underrun a net without entangling the superstructure.
Some nets are towed by surface vessels. The process is necessarily
slow, and to be effective the surface vessel must know the exact
location of the submersible. Towing torpedoes or high explosive
charges behind moving vessels has been developed by the Italian Navy,
but the chances of hitting a submersible with such devices are not
very great.
Bomb-dropping from aëroplanes can be practiced successfully under
exceptional conditions only. In view of the fact that such
bomb-dropping is exceedingly inaccurate, and that the charges carried
are relatively small, this form of attack ordinarily would not be very
dangerous for the submersible. Surface craft have also employed large
charges of high explosives, which are caused to detonate by
hydrostatic pistons upon reaching a certain depth. Patrol boats carry
such charges in order to overrun the submersible, drop the charges in
its vicinity, and by the pressure of the underwater explosion crush
its hull. Since the pressure of an underwater explosion diminishes
rapidly as the distance increases from the point of detonation, it
would be necessary to place the explosive charge fairly close to the
hull of the submersible to be certain of its destruction. To
accomplish this, it would seem that the ideal combination would be the
control of an explosive carrier by radio energy directly from an
aëroplane. Thus we would have a large explosive charge under water
where it can most effectively injure the submersible, controlled by
the guidance of an observer in the position best suited to watch the
movements of the submerged target.
The third method by which to frustrate the attack of the submersible
is to give better protection to the merchant marine itself. While a
great deal of ingenuity is being concentrated on the problem of
thwarting the submersible, but little common sense has been used.
While endeavoring to devise intricate and ingenious mechanisms to sink
the submersible, we overlook the simplest safeguards for our merchant
vessels. To-day, the construction of the average ship is designed to
conform to the insurance requirements. This does not mean in any way
that the ship is so constructed as to be truly safe. Thousands of
vessels that are plying the seas to-day are equipped with bulkheads
that are absolutely useless because they do not extend high enough to
prevent the water from running from one part of the ship to another
when the ship is partially submerged. Then again, the pumping system
is so arranged as to reach the water in the lower part of the hull
when the ship is up by the head. Should the ship be injured in the
forward part and sink by the head, these pumps would be unable to
reach the incoming water before her condition had become desperate.
There is a vessel operating from New York to-day worth approximately a
million dollars, and if she were equipped with suitable pumps, which
would cost about a thousand dollars, her safety would be increased
about forty per cent. Her owners, however, prefer running the risk of
losing her to expending a thousand dollars! If the merchant vessels
were made more torpedo-proof, it would be an important discouragement
to the U-boat commander. During the past two years of the war,
nineteen battleships have been torpedoed, and out of this number only
three have been sunk, showing that it is possible by proper
construction to improve the hull of a ship to such an extent that it
is almost torpedo-proof. While it may not be practicable, on account
of the cost, to build merchant vessels along the lines of armed ships,
nevertheless much could be done to improve their structural strength
and safety; and since speed is an essential factor in circumventing
torpedo attack, new cargo-carriers should be constructed to be as fast
as is feasible.
So radically have conditions changed that to-day we have a
superabundance of useless dreadnaught power. The smaller guns of some
of these vessels, and their gun crews, would be far more useful on the
merchant vessels than awaiting the far-off day when the German fleet
shall venture forth again. The submersible must be driven below the
surface by a superiority of gunfire on the part of the merchant marine
and its patrols. In this way the submersible would be dependent upon
the torpedo alone, a weapon of distinct limitations. In order to use
it effectively, the submersible must be not more than from eight
hundred to two thousand yards from its target, and must run submerged
at reduced speed, thus greatly lessening its potentiality for
destruction. To-day, submersibles are actually running down and
destroying merchant vessels by gunfire. If merchant vessels carried
two high-speed patrol launches equipped with three-inch guns of the
Davis non-recoil type, and these vessels were lowered in the danger
zone as a convoy to the ship, such a scheme would greatly lessen the
enormous task of the present patrol. In the event of gunfire attack by
a submersible, three vessels would be on the alert to answer her fire
instead of one: an important factor in discouraging submersibles from
surface attack!
The future of the submarine campaign is of vital importance. The
prospect is not very cheerful. Laubeuf states that at the beginning of
the war Germany had not over thirty-eight submersibles. This statement
may be taken with a grain of salt; the Germans do not advertise what
they have. It is probable, however, that to-day they have not more
than two hundred submersibles in operation. Over four thousand patrol
boats are operating against this relatively small number, and yet
sinkings continue at an alarming rate. It is estimated that Germany
will be able to produce a thousand submersibles in the coming year and
man these vessels with crews from her blockaded ships. This will be a
tremendous addition to the number she has now in operation. The
greater the number of submersibles she has in action, the greater the
area the submarine campaign will cover. The number of patrol vessels
will have to be increased in direct proportion to the area of the
submarine zone. Since a large number of patrol boats has to operate
against each submersible, it will be seen that a tremendous fleet
will have to be placed in commission to offset a thousand
submersibles. Thus the problem becomes increasingly difficult, and the
protection of the trade route will be no more thoroughly effected than
it is to-day--unless we overwhelm the enemy by a tremendous fleet of
destroyers.
FOOTNOTES:
[1] The "Majestic" was torpedoed at the Dardanelles, while at anchor.
The "Triumph" was torpedoed while moving slowly; both warships had out
their torpedo nets.
[2] The Germans have in operation submersibles of 2000 tons
displacement.
[3] Big strides, however, have been made lately in overcoming these
shortcomings, and it would appear that the principle of sound-detection
is the most hopeful one for us to follow.
THE JOURNAL OF SUBMARINE COMMANDER VON FORSTNER
I
ORDERED TO COMMAND A SUBMARINE
Every year about the first of October, at the time of the great army
maneuvers, new appointments are also made in the navy; but, unlike our
army brothers, who from beginning to end remain permanently either in
the artillery, cavalry, or infantry, we officers of the navy are
shifted from cruiser to torpedo boat, from the ship of the line to the
hated office desk on land at the Admiralty, in order to fit us to
serve our Almighty War Lord in every capacity and to the best
advantage. The commander of a torpedo boat must be familiar with the
service on board a dreadnaught or on any other large ship, for only
those who are intimately acquainted with the kind of ship they are
going to attack possess sufficient skill to destroy it.
For the first time in the autumn of 190- some of us were surprised at
the announcement: "Ordered on board a submarine." This order naturally
met with an immediate response, but it brought a new outlook on the
possibilities of our career, for we had not yet been trained to this
branch of the service which our Almighty War Lord had only recently
added to the Imperial Navy. The question was, should we be able to
perform this new duty?
It is well known that the French were the first to complete a type of
submarine navigable underseas, and the English unwillingly, but with a
sly anticipation of coming events, copied this type of boat.
To all outward appearance we kept aloof from following the example of
our neighbors, and our chiefs of the Admiralty were beset with
expostulations on the subject, but they were silently biding their
time while our enemies of to-day were bragging about their successful
experiments with their newly constructed submarines. To the dismay and
astonishment of our opponents it was only when the right hour had
struck that our navy revealed that it had similar weapons at its
command; it therefore prepared for them some disagreeable surprises,
and set its special seal from the very beginning on the maritime
warfare.
I remember a talk I had with an old army officer a few years ago, when
I had just received my appointment to a submarine. We were speaking of
U-boats and aëroplanes, and he exclaimed: "Ach! my dear Forstner, give
it up! The bottom of the ocean is for fishes, and the sky is for
birds."
What would have happened to us in this war had we not so proudly
excelled above the earth and beneath the sea?
At first a mystery still veiled our knowledge concerning our
submarines; we were told that the dear, good, old U-boat No. 1 had
splendidly stood every test, and shortly after, in October, 190-, I
went on board, and had the honor later to command her for two years.
But during this period, for several years, the greatest secrecy
surrounded this new weapon of our navy; strictest orders were given
to admit no one on board, not even high officers; only admirals were
allowed to penetrate within, and on every matter concerning our
U-boats we had to maintain absolute silence. Now, however, that our
usefulness has been so fully justified, the veil of discretion can be
somewhat lifted, and I can describe within certain limits the life and
activities on board a submarine.
II
BREATHING AND LIVING CONDITIONS UNDER WATER
A submarine conceals within its small compass the most concentrated
technical disposition known in the art of mechanical construction,
especially so in the spaces reserved for the steering gear of the boat
and for the manipulation of its weapons.
The life on board becomes such a matter of habit that we can
peacefully sleep at great depths under the sea, while the noise is
distinctly heard of the propellers of the enemy's ships, hunting for
us overhead; for water is an excellent sound conductor, and conveys
from a long distance the approach of a steamer. We are often asked,
"How can you breathe under water?" The health of our crew is the best
proof that this is fully possible. We possessed as fellow passengers a
dozen guinea pigs, the gift of a kindly and anxious friend, who had
been told these little creatures were very sensitive to the ill
effects of a vitiated atmosphere. They flourished in our midst and
proved amusing companions.
It is essential before a U-boat submerges to drive out the exhausted
air through powerful ventilating machines, and to suck in the purest
air obtainable; but often in war time one is obliged to dive with the
emanations of cooking, machine oil, and the breath of the crew still
permeating the atmosphere, for it is of the utmost importance to the
success of a submarine attack that the enemy should not detect our
presence; therefore, it is impossible at such short notice to clear
the air within the boat. These conditions, however, are bearable,
although one must be constantly on the watch to supply in time fresh
ventilation.
Notwithstanding certain assertions in the press of alleged discoveries
to supply new sources of air, the actual amount remains unchanged from
the moment of submersion, and there is no possibility, either through
ventilators or any other device so far known in U-boat construction,
to draw in fresh air under water; this air, however, can be purified
from the carbonic acid gas exhalations by releasing the necessary
proportion of oxygen. If the carbonic acid gas increases in excess
proportion then it produces well-known symptoms, in a different
degree, in different individuals, such as extreme fatigue and violent
headaches. Under such conditions the crew would be unable to perform
the strenuous maneuver demanded of it, and the carbonic acid must be
withdrawn and oxygen admitted.
The ventilation system of the entire submarine is connected with
certain chemicals, through which the air circulates, whose property is
to absorb and retain the carbonic acid. Preparations of potassium are
usually employed for this purpose. Simultaneously, cylinders of
oxygen, under fairly high pressure, spray oxygen into the ventilation
system, which is released in a measure proportionate to the number of
the crew; there is a meter in the distributing section of the oxygen
tubes, which is set to act automatically at a certain ratio per man.
The ordinary atmosphere is bearable for a long time and this costly
method of cleansing the air is used only as a last resort; the moment
at which it must be employed is closely calculated to correspond, not
only with the atmospheric conditions at the time of submersion, but
also to the cubic quantity of air apportioned to each man according to
his activities and according to the size of the boat.
It is unnecessary to clear the air artificially during a short
submersion, but during prolonged ones it is advisable to begin doing
so at an early hour to prevent the carbonic acid gas from gaining a
disproportionate percentage, as it becomes then more difficult to
control, and it is obvious that it is impossible to dissipate the
fumes of cooking, the odors of the machine oil, and the breath of the
crew.
Taken altogether one can live comfortably underseas, although there is
a certain discomfort from the ever-increasing warmth produced by the
working of the electrical machinery, and from the condensation created
by the high temperature on the surface of the boat plunged in cold
water, which is more noticeable in winter and in colder regions.
It is interesting to observe that the occupations of the crew
determine the atmospheric conditions: the quantity of air required by
a human body depends entirely on its activity. A man working hard
absorbs in an hour eighty-five liters of air. Besides the commander,
who is vigorously engaged in the turret,--as will be hereafter
described,--the men, employed on the lateral and depth steering, and
those handling the torpedo tubes, are doing hard physical work. The
inactive men use up a far smaller quantity of air, and it is
ascertained that a man asleep requires hourly only fifteen liters of
air. A well-drilled crew, off duty, is therefore expected to sleep at
once, undisturbed by the noise around them, and their efficiency is
all the greater when the time comes to relieve their weary comrades.
We had a wireless operator on board whose duties ceased after
submersion, and he had so well perfected the art of sleeping that he
never cost us more than fifteen liters of air, hourly, underseas.
The length of time that a U-boat can remain under water depends, as we
stated above, on the atmospheric conditions at the moment of
plunging, and on the amount of oxygen and chemicals taken on board. We
can stay submerged for several days, and a longer period will probably
never be necessary.
The distance of vision varies somewhat under water, as we look out
from the side windows cut into the steel armor of the commander's
conning tower. We can naturally see farther in the clear water of the
deep ocean than in the turbid, dirty water at the mouth of a river,
and the surface of the water-bottom has a direct influence on the
sight, which is far more distinct over a light sand than over dark
seaweed or black rocks, and at an upper level the sunshine is
noticeable many meters under water. But in any case, the vision
underseas is of the shortest, and does not extend beyond a few
meters; light objects and even the stem and stern of our own boat are
invisible from the turret. We are unaware, therefore, of advancing
ships, derelicts, or projecting rocks, and no lookout can preserve us
from these dangers.