THWARTING THE U-BOAT.
NETS TO ENTANGLE THE SEA SHARKS OF WAR--"CHASERS" OR "SKIMMING-DISH"
BOATS--"BLIMPS" AND SEAPLANES--HUNTING THE SUBMARINE WITH "LANCE," BOMB
AND GUN--A SAILOR'S DESCRIPTION.
The advantage which Germany gained by the development of what has been
termed the super-submarine placed the other nations where it became
absolutely necessary for them to concentrate their energies in an effort
to counteract the devastation which the U-boats brought upon the seas.
England tried first to protect the English channel and many of its ports
with mines, floating bombs and submarine nets, and while the latter
served as barriers which prevented the submarines penetrating into some
of the important waters and harbors, they could act merely in a
protective sense.
The submarine net is a specially devised net with heavy iron or wire
meshes, similar to a fishing net. These nets--miles in length--were born
of the nets originally devised to sweep harbors clear of mines. They are
carried between two boats described as trawlers, which are a form of
sea-going tug with powerful engines, that can draw a heavy load. A heavy
cable runs from trawler to trawler, and from this the chain net is
suspended in the water. It is heavily weighted at the bottom so as to
hold it in a perpendicular position. The trawlers steaming along, side
by side, sweep up with the net anything which may be placed in the water
for the purpose of blowing up or injuring vessels.
The submarine nets in some places have been anchored to form a regular
barrier against the passage of submarine boats, and in this way were
effective, but their use could in no way restrict the underseas boats in
their work upon the open seas.
The most effective plan of overcoming the dire consequences of the
U-boat warfare was found, therefore, to lie in the use of submarine
chasers and airships, the two operating together in conjunction with the
battleships, cruisers and torpedo boat destroyers.
The submarine chaser is a light-draught, high-powered, skimming-dish
type of husky motorboat, mounting rapid-fire, 3 or 4-inch guns. In order
to prove effective against the submarine it is necessary to have many of
these boats, and it is a matter of particular interest that the
marvelous resources of the United States at the time of her entrance
into the war enabled her to immediately begin a campaign for the
construction of chasers, which would be able to guard the seas in the
channels of traffic and along the ports into which the submarine might
attempt to sneak.
NO EXPERT NAVAL KNOWLEDGE REQUIRED.
The operation of the chaser does not require the degree of technical
skill and knowledge of naval strategy required in the handling of ships
of the naval type. A fleet of chasers is manned largely by naval
reserves, who have a certain amount of training, but who are neither
navigators nor experts in naval affairs. The operations are, however,
directed by the naval authorities.
The submarine chaser is effective because it draws very little water,
has high speed, can be quickly turned and diverted from its course and
does not present any great depth of hull at which the submarine can fire
a torpedo. It would be possible for a torpedo to pass under a chaser
without hitting it--if the submarine cared to waste such an expensive
weapon on so small an adversary. When the submarine attempts to come to
the surface and use the rapid-fire gun with which she is armed she is at
a disadvantage, because it takes her several minutes to emerge.
Additional time is required to swing the gun up through its automatic
hatch while the men scramble to the deck to man it.
The chaser, with a speed of approximately 35 to 40 miles an hour, will
travel somewhere between a mile and a half to two miles in this period.
Its gun has been ready from the start, and the chaser has had half a
dozen shots or so with only a single hit needed to put the submarine out
of commission. Even if the submarine is at the surface and has her gun
mounted ready for action, she is at a disadvantage with the chaser. The
chaser, taking advantage of her speed and small size, goes skimming
across the water at the rate of 40 miles an hour, and it takes a mighty
fine gunner to be able to hit a small craft, going in a zigzag course
over the water at such speed.
The chaser may continue to circle the submarine awaiting her opportunity
which will of necessity come when the U-boat attempts to submerge. The
submarine must go through the regular form of running back her gun, and
battening down the water-tight hatches, before she can submerge, and the
latter process again takes several minutes. Therefore while the
submarine is preparing to dip, the chaser can run upon her and let loose
the fire from its rapid-fire gun.
A POOR SURFACE FIGHTER.
The submarine, by very virtue of the qualities which make it a good
submarine, is a poor boat for surface fighting. It can carry no very
heavy armament, and it is not heavily armored. The problem of stowing
away all the heavy machinery, supplies, torpedoes and devices necessary
for her operations and maneuvering has presented about all the
difficulties the constructors have been able to handle. The highest
speed of the submarine is not in excess of 20 miles an hour. The
submarine must be light and easy to handle. It gains in steadiness and
certainty of operation with increased size, but it loses in capacity for
quick and delicate maneuvering.
In addition the submarine has what is termed a strategic vulnerability.
A shot which might mean nothing more serious than a hole in the side to
a surface boat would end the submarine's usefulness for underseas work
and convert her into a helpless hulk of surface craft.
The submarine is an easy quarry for a chaser, for even when submerged
and moving along, the U-boat creates a distinct wave on the surface of
the water which can be followed by the chaser. The little boats are just
what their name implies--chasers--and besides having the qualities
already described they may conceal themselves behind large steamers, and
when the submarine in preparing to launch a torpedo makes its presence
known the chaser may speed from its hiding place and drive the underseas
craft away, even if it does not succeed in injuring it.
OPERATING IN CONNECTION WITH AN AEROPLANE.
The chasers also have a special facility of operation in connection with
the aeroplane or seaplane, principally because of their high speed; and
next to the chaser the aeroplane is one of the submarine's worst
enemies. Used in conjunction with the regular torpedo boat destroyers of
the navy, the chaser and the aeroplane promise in future wars to
minimize the effectiveness of the underseas craft. This is proven by the
fact that immediately after the United States naval forces joined those
of the Allies in European waters, the disasters resultant upon submarine
attacks were greatly reduced. The speedy destroyers, while not actually
sinking many submarines, by their vigilance prevented the submarine from
operating.
Large types of the chasers ordered in this country by the Russian
Government are 72 feet long by 11 feet 3 inches wide and draw 3 feet 3
inches of water. Each boat carries three of the 8-cylinder 6-3/4 x 7-3/4
Duesenberg, 350 to 400 horsepower motors. The boats carry an 18-inch
torpedo tube amidships and a 47-millimetre rapid-fire gun on the forward
deck. They are controlled from the bridge deck with a sheltered cabin
for the quartermaster, with controls from either the shelter or bridge
deck. They have a guaranteed speed of twenty-eight knots.
Deck arrangements consist of the following: A hatch to the fo'castle,
followed by; the emplacement for the rapid-fire gun. Following this is
the steering shelter containing duplicate controls, &c., for the engine
room and for the steering. Immediately aft of the steering shelter is
the bridge deck, located on top of the engine room trunk house. The
entire after half of the vessel is a clear sweep of deck with the
exception of a booby hatch to crews' quarters well aft.
The boats are arranged for wireless with foremast and jigger mast. Rail
stanchions in the way of the torpedo tube are hinged down, giving clear
sweep to the tube for firing purposes.
PROVISION FOR OFFICERS AND CREW.
Below decks ample space has been provided for the crew and officers. The
forepeak is arranged for chain lockers and bosun's gear lockers,
followed by ship's galley, which has two pipe berths. Next to the galley
is located the officers' cabin and wireless room, which is entered by a
hatch from the steering shelter. This cabin accommodates two officers
and includes lavatory, officers' desks, wireless desk and folding mess
table.
Next aft is the machinery space, in which are located the three eight
cylinder Duesenberg motors, a three k.w. universal lighting set, the
necessary oil tanks, batteries and a work bench. The next compartment
contains fuel tanks, with 1300 gallons capacity. Aft of this compartment
is located the crew's quarters, berthing eight men, with lavatory
attached. The hull is divided into six water-tight compartments by steel
bulkheads.
The hull is of wooden construction, as developed for this service by the
builders.
The 72-footers develop a speed of twenty-eight knots and have a cruising
radius exceeding 1200 miles. The design of the hull is the concave
bottom, square bilge type, developed for this particular service. It
furnishes a steady gun platform, which, with the necessary speed, is
the most vital feature of a submarine chaser.
The demand for speed and stability was borne out by the experience of
the Russian and Italian navies in their active work and no consideration
at all is given propositions from these two countries which do not range
well about twenty-five knots.
Exceptional success was attained by the Russian Black Sea and by the
Italian high speed fleets in actual use and their demand for exceptional
speed was based on experience.
It is a well known fact that the Russian government was successful in
patrolling its shores and in protecting its harbors and shipping. The
Italian government also was exceptionally successful in maintaining its
mercantile fleet in comparative safety and in protecting its harbors
against the offensive work of enemy submarines. The entire Italian fleet
of submarine chasers consists of high speed, high powered motor patrol
boats, most of which were equipped with American made motors.
CATALOGUED AS "PATROL BOATS."
In a general way the "chasers" are catalogued in naval circles as
"patrol boats." England has thousands of them, ranging from motorboats
to naval auxiliaries, raking the English Channel, the North Sea and the
waters all about the British Isles. As a rule the boats work in groups
of five or six, one boat serving as a flagship--and often there is a
"blimp" attached to the fleet. The armament of these small vessels is
distinctive. Each carries, besides a deck gun, a "depth charge," half a
dozen lance bombs and arms for each member of the crew. The deck gun
fires a shell that weighs about thirteen pounds.
The "depth charge" is a submarine bomb, so constructed that it is
discharged at any determined depth of water when thrown overboard. If
the water is 100 feet deep the bomb will explode at that depth. The
bombs are used to drop in places where the submarine has been located
or is expected of lurking in the bottom of the sea. While the exploding
bomb may not strike the underseas boat it will create havoc on board the
underwater craft if discharged in close proximity, the extra water
pressure exerted causing disarrangement of the delicate mechanism, if
not rendering the boat unfit for service.
Some of the patrol boats of the English have been armed with "lance
bombs." These are bombs of highly explosive character which are fastened
to the end of a long pole or staff. They are used just as a harpoon is
used when by chance a submarine may emerge from the water in too close
proximity to the chaser. It is not of record that any U-boats have been
sunk with these strange javelins, but official reports show that the
boats are armed with them for emergencies.
CHASER TROUBLES THE SUBMARINE.
What with dragging bombs through the water, and setting traps and nests
for the submarines, the chasers make great trouble for the underseas
craft, but the ingenious Germans are constantly on the alert, and it has
been proved that in one or two instances at least the submarines cut
their way through the heavy chain nets which were set to catch them near
Havre. It was said that the submarine was provided with steel knives or
wire cutters, and shears operated by electricity or pneumatic pressure,
which enabled the boat to cut its way through the barrier of chains and
wires.
As a means of visualizing the operations of the "chaser" and giving some
idea of the excitement which attends the attempt to run down the
underseas craft, the following description by an English sailor is
interesting. The chase occurred off the Isle of Wight:
"Offshore a short distance was a patrol boat lying very low and flying
distress signals. We had run over to her and learned that about an hour
before the periscope of a submarine had been stuck up not far from her,
then the craft had submerged, appeared again about a mile away, and
fired four shots, which let in enough water slowly to sink the patrol,
which before the war had been nothing but a dirty little trawler.
"Finding the crew of the patrol could take care of themselves in their
small boats and learning that the submarine had run over to the
westward, where we knew chain net traps to be laid, we circled in that
direction.
"Our powerful motors thrummed evenly. The water seemed to part ahead of
us, and the gunners squinted along the surface, looking for the glimpse
of a periscope or the first sign of the hull of the U-boat if she should
be proceeding awash.
CREW THRILLED WITH JOY.
"Suddenly, off to the west, we made out her periscope. Intense joy
thrilled our little crew. She was inshore from us. She was between our
circular course and the chain nets--in the trap. The periscope we had
seen might be a dummy, for a submarine frequently casts loose a phoney
periscope to draw fire, but, at any rate, she must have been between us
and the nets if she cut it loose.
"Presently, probably after a look around, the periscope suddenly
disappeared, and we knew it was a real one with a German U-boat on the
end of it. Like a flock of falcons we were swooping down on the prey.
"Abruptly the lead boat comes to a dead stop and lists heavily to
starboard. Evidently something is wrong. We see men crawl out over the
stern and fish around with boat hooks and poles. Cold as it is, one man
goes overboard and remains under water so long we could not believe he
would come up alive. The boat had fouled the chain nets.
"Circling round in an ever smaller radius, we search the water for a
periscope, a shadow, or the conventional 'streak of dirty grease' or
'line of bubbles.'
"All of us have towing torpedoes out. These are bombs on long cables
which are towed astern and sink to a certain specified depth. If the
cable fouls anything at all, as the boat goes ahead, the bomb pulls up
to it, and, when it bumps, it explodes.
"We are in line. Suddenly there is a crash and a roar just ahead of us.
I am thrown off my feet. Barrels of water splash down into our cockpit
and roll off the decks. The bow lifts itself clean for a second. I think
that the submarine has blown us up. Perhaps I am dead already.
"Then we settle down again, and except for a scared look on the faces of
a couple of men and rather nervous, forced jests on the lips of others,
we are plowing ahead just as before.
"Nothing has happened except the towing torpedo of the boat in front of
us in the line fouled a submerged spar, or a bit of wreckage, and
exploded right under our bow. 'If we had been a few yards closer we
would never have been there any more.'
FOULS A SUBMERGED SPAR.
"As we realized what had happened, our tongues were loosened, and, if
the crew of the boat ahead could have heard what we said about them, we
would have lost their friendship most assuredly.
"Way inshore, after a circling chase of perhaps twenty minutes, the
submarine came up. She was in such shallow water that she probably was
having trouble in operating submerged. She was gone then.
"What followed was very business-like. It illustrates the attitude the
British have come to take toward the submarines because of their
flagrant violations of every form of international law and decency. It
is the attitude which any country, obliged to fight against them, will
assume. To the British mind, submarines must be exterminated, just as
one would exterminate a nest of poisonous vipers, or a nest of hornets.
People ask me how many submarines are being captured now. Very few! Many
are destroyed, but few captured.
"No sooner did the hull of the submarine show itself than we began to
hammer her with our three-inch guns. She opened fire, but her shots went
wild, and, in a few seconds, she disappeared.
"As fast as we could, we ran over to where she had gone down. If the
principles which obtain on land, in the air or in the navy at large,
existed in submarine warfare, we would have gone over to see if we could
rescue any of the wounded, but it was a U-boat and we simply made sure
that there was nothing left of the craft.
"About where she went down, a quantity of gas and air bubbles were
rising, and the dirty patch of oil was once more in evidence. That was a
pretty certain sign the career of one U-boat was at an end, for the sea
must have been pouring into her, and even though all her crew did not
drown, once the salt water reached the storage batteries, the chloride
would do the work.
WERE TAKING NO CHANCES.
"But we are taking no chances. We circle round and round the spot and
drop depth bombs--deadly machines. These are powerful explosives which
are set so they will detonate at a certain depth. We first sounded the
bottom and then set our bombs for ten fathoms. Suddenly I hear a cry
from the boat behind us. One of the crew reaches out, grabs the collar
of a man who has just dropped a depth bomb over the stern and yanks him
unceremoniously into the cockpit. At a glance I see what has happened.
"The engineer has stalled his motor--just as the bomb was let go. It
sinks slowly, and there is a slight momentum left in the
submarine-chaser. We hold our breath and watch in suspense, expecting
any second to see our comrades hurled into the air among a mushroom of
water and splinters.
"There is no way to help them. Suddenly there is a muffled roar, a
column of water rises to what seems a hundred feet, and falls back,
drenching every one who is near it. But our comrades are unhurt. The
momentum of their boat has carried them just far enough to save them
from being blown to atoms. That is the second narrow escape for our
little squadron in this chase after a single submarine.
"But our work is done. There is no doubt now about the fate of the
U-boat. It is not necessary for one of the depth bombs actually to come
in contact with the submerged craft to destroy it. When under water, a
submarine's rigidity is multiplied. Its elasticity is next to nothing.
An explosion as powerful as that of a depth bomb near it, is almost
certain to cripple it if not destroy it. It is the same principle as
that which kills fish in a pond when dynamite is exploded beneath the
surface of the water. The shock is sufficient to kill the men in the
U-boat, and so we glide along homeward, secure in the knowledge that
even if our gunfire did not finish the enemy, the bombs have done the
work. On the surface, we notice swarms of dead fish."
THE HAWK-EYED AEROPLANE.
The last wrinkle developed for submarine hunting was the aeroplane. Like
a fish-hawk it can see its prey beneath the water by flying high in air.
Another step just a bit in advance of aeroplane scouting for submarines
is the use of a small dirigible for the same purpose. But the cleverest
development of the aeroplane-submarine idea involved the use of
seaplanes for the purpose of launching submarine torpedoes at enemy
ships.
Here's how this is practiced. As most folks know, the seaplane differs
from the land-flying craft in that it rides on floats instead of wheels.
These floats permit the seaplane to come to rest on the waves, and to
launch itself again. Between these floats, which resemble a pair of
broad home-made sleds, may be slung a torpedo. The same type of missile,
this, that is used by the submarine and the destroyer--a long,
cigar-shaped cylinder, operated by compressed air driving a propeller,
and equipped with a warhead filled with guncotton. The torpedo is held
by slings, delicately adjusted so that they can be released in an
instant.
The great seaplane, swinging the missile of death between its giant
floats, climbs the skies in search of an enemy ship. From a distance of
miles, perhaps, the seaplane looks like a gull. To the observer in the
plane, however, sweeping the horizon with his binoculars, a ship is
plainly and easily seen.
NOT TO BE OUT-DISTANCED.
Off in the distance is spied a ship suspected of being an enemy
transport. It isn't hard to determine--the ship cannot steam away from
them, no matter how swift its engines. A seaplane can go so fast that it
makes the fastest torpedo boat destroyer look as if it were standing
still. The attacked transport may try to bring its anti-aircraft guns to
bear, if luckily it is equipped with them. Failing this, the soldiers
will man the decks with their rifles ready. Then there is a duel of
skill and daring between the men on the cruiser and the lone fighters in
the seaplane.
The seaplane must swoop sufficiently close to the water to release the
torpedo and let it drop without damage. And this must be done from a
sufficient distance to safeguard the seaplane from the vessel's guns.
The superior speed and mobility of the seaplane gives it a great
advantage over the ship attacked.
Another of the weapons or instruments of warfare devised largely for use
in destroying the evil submarine is the "blimp." This is nothing more
nor less than a small dirigible balloon, hundreds of which the United
States government started to build when it entered the war.
The blimp is an aerial sea-scout. Its principal employment is for
observation. It is a watcher of enemy movements on the water. But it is
also serviceable for attack, and especially for assailing submarines.
The British used blimps for the latter purpose, and to great advantage.
The dirigible sausage-balloon, when a submarine is descried, can hover
over it (as an aeroplane cannot), remaining as nearly stationary as may
be desired, and waiting for an opportunity to drop a bomb with accurate
aim.
If the submarine be under water, and its presence betrayed by the
peculiar surface-ripple that marks its wake, a bomb with a delay-action
fuse can be dropped upon it, the projectile not exploding until it
reaches a depth of fifty feet or so. In case the first bomb does not
score a hit, there are others to follow, with better luck perhaps.
THE IMPORTANCE OF THE "BLIMP."
Thus, it will be seen that the blimp is an important auxiliary of the
flying-machine in the pursuit of the submarines. Both together, in this
exciting sport, supplement the swift power-boats called
"submarine-chasers."
For some time the Navy Department has trained enlisted men and officers
for this work, chiefly at a Gulf port, where a school--it is no war
secret--of aviation and ballooning has been maintained. Six officers and
40 men are required for each coast station.
The Navy Department adopted for the blimp a standardized pattern, with
definite published specifications, in accordance with which contractors
turned them out in numbers. It is a sausage-shaped balloon 160 feet
long, with a great diameter of 31-1/2 feet, and containing, when
inflated, 77,000 cubic feet of hydrogen gas.
The fabric of the "envelope"--that is to say, of the gas-bag--is coated
both outside and inside with rubber. It is required that the balloon
shall not lose more than 1 per cent of its gas-content in 24 hours. When
inflated it must be able to carry (including its own weight) a total of
5275 pounds.
If the "Zeppelin" be excepted, the blimp is the most highly-developed
and scientific heavier-than-air flying machine ever devised. It has a
cruising speed of 35 miles an hour, but at a pinch can travel ten miles
an hour faster. At the "cruising" rate, it carries enough gasoline to
keep going for sixteen hours; at 45 miles, its load of "petrol" will
suffice for ten hours.
Even the best war balloons of a few years ago were at the mercy of the
winds. It is not so with the blimp. Barring storms, it is able to
navigate the air as it wishes. It can rise safely to an altitude of a
mile and a half. To furnish fuel for its engine of 100 horsepower it
carries, in two tanks, 100 gallons of gasoline.
DESCRIPTION OF THE "BLIMP."
In effect, the blimp is a combination of balloon and aeroplane. Like the
latter, it is provided with "skids" (resembling sled runners and made of
ash wood), or sometimes with bicycle wheels, for safe landing on terra
firma. When designed for sea scouting, floats--cylinders of waterproof
fabric stuffed with vegetable fibre--are attached to the skids, or to
the wheels, so that the airship, in calm weather, may be able to rest,
like a sea bird, on the waves, if desired.
The blimp's balloon envelope must contain two smaller balloons, together
holding 19,250 feet of hydrogen gas. The idea, of course, is that if
anything happens to the major balloon--puncturing by gunfire or by other
mishap--the "balloonets" inside of it will keep the machine afloat.
The wingless aeroplane is suspended from the balloon by cables of
galvanized wire. There is a special arrangement by which the
"pilot"--the man who steers and operates the airship--can at any time
measure the pressure of hydrogen in the balloon, thus knowing what he
has to count on in the way of carrying power.
The front part of the blimp's car is occupied by the engine and
radiator, behind which is a bulkhead of sheet steel. In the rear of this
bulkhead sits the pilot, and behind him the "observer," who makes
sketches and takes notes of anything important that he sees. Behind the
observer are the tanks for fuel oil and 300 gallons of water ballast.
The body of the car is covered with aeroplane linen, save for the
engine, which is sheathed with sheet aluminum.
In order to hold whatever position in the air may be desired, the blimp
is equipped with two horizontal fins and three vertical fins. Not every
blimp, that is to say, but the pattern approved and required of
contractors by the Navy Department. These fins are made of wood and
light steel tubing, reinforced with wire, covered with aeroplane linen
rubber painted and finished with varnish.
THE "BLIMP" WELL EQUIPPED.
There are also two horizontal rudders and two vertical rudders, for
steering up and down or sidewise. They work on ball bearings. A blimp,
one should understand, is a fish in the ocean of air, a swimmer--just as
the aeroplane is a flyer, like the bird.
The blimp's "car" carries an electric storage battery to furnish lights.
The same battery energizes a searchlight for night scouting. A wireless
apparatus, for transmitting information to the shore station, is part of
the equipment.
The blimp, as already stated, is a sea scout. It is meant to be operated
from a base on shore--which base is in constant communication by
telegraph and wireless with the great radio stations that are strung all
along our coasts at intervals of 200 miles. These stations, in turn, are
in communication with the huge wireless outfit at Arlington (across the
Potomac from Washington), whose "antennae," uplifted on tall steel
towers, receive instantaneous war news from half the world.
Thus if (just for illustration) a blimp spies a hostile submarine, the
news is instantly transmitted to the Navy Department. The department
orders its "chasers" and warplanes nearest to the scene to go after the
undersea boat. Within a few minutes the pursuit has started, and the
U-boat finds itself in much the same situation as a fox hunted by
hounds. In this case, however, the hounds are in the air, as well as
"quartering" the aqueous terrain.
The United States' blimps are modeled on European patterns. But they are
to have special improvements of their own. To make sure of their
efficiency and structural correctness, each contractor, in offering bids
to furnish them, was required to exhibit a model, exactly like the
sausage balloons he proposed to make, but of toy size--one-thirtieth the
length of the full-sized, completely equipped aerial sea scout.