SURFACE BOATS
The war on the submarine was fought mainly from the surface of the
sea and from the air above the sea, and naturally it resulted in many
interesting naval developments.
As described in Chapter XIII, the first offensive measure against the
U-boat was the building of swarms of speedy motor-boats which drove the
invaders away from harbors and into the open sea. To follow the U-boats
out into rough water larger submarine-chasers were built, but even they
could not cope with the enemy far from the harbors.
MOTOR TORPEDO-BOATS
The Italians made excellent use of speedy motor-boats in the protected
waters of the Adriatic Sea. One type of motor-boat was equipped with
two torpedo-tubes in the bow. Small 14-inch torpedoes were used, but
as each torpedo carried two hundred pounds of high explosive, the
motor-boat was a formidable vessel if it crept in close enough to
discharge one of these missiles at its foe.
On one occasion, a patrol of these little boats sighted a couple of
Austrian dreadnoughts headed down the coast, surrounded by a screen
of ten destroyers. Favored by the mist, two of the motor-boats crept
through the screen of destroyers, and torpedoed the battle-ships. Then
they made good their escape. A destroyer that pursued one of the boats
decided that the game was not worth while when it was suddenly shaken
up by the explosion of a depth bomb dropped from the motor-boat.
THE SEA TANK
The Italians showed a great deal of naval initiative. They were forever
trying to trap the Austrian fleet or to invade its harbors. Like all
other naval powers, the Austrians protected their harbors with nets and
mines. It was impossible for submarines to make an entrance and the
ports were too well fortified to permit an open attack on the surface.
Nevertheless, the Italians did break through the harbor defenses on one
or two occasions and sank Austrian war-vessels. Again it was with a
small boat that they did the trick.
The nets which the Austrians stretched across their harbor entrance
were supported on wooden booms or logs which served as floats. These
booms offered an effective bar to small boats which might attempt to
enter the harbor under cover of darkness. But the Italians found a way
to overcome this obstruction. They built a flat-bottomed motor-boat
which drew very little water. Running under the boat were two endless
chains, like the treads of a tank. In fact, the boat came to be known
as a "sea tank." The chains were motor-driven and had spiked sprockets,
so that when a boom was encountered they would bite into the wood and
pull the boat up over the log, or maybe they would drag the log down
under the boat. At any rate, with this arrangement it was not very
difficult to pass the boom and enter the harbor. At the rear the chains
were carried back far enough to prevent the propeller from striking
when the boat had passed over the log.
[Illustration: Courtesy of "Scientific American"
An Italian "Sea-tank" climbing over a Harbor Boom]
[Illustration: (C) Underwood & Underwood
Deck of a British Aircraft Mothership or "Hush ship"]
THE AWKWARD "EAGLES"
A curious boat that we undertook to furnish during the war was a cross
between a destroyer and a submarine-chaser. After the submarine had
been driven out to sea its greatest foe was undoubtedly the destroyer,
and frantic efforts were made to turn out as many destroyers as
possible. But it takes time to build destroyers and so a new type of
boat was designed, to be turned out quickly in large numbers. A hundred
and ten "Eagles" (as these boats are called) were ordered, but the
armistice was signed before any of them were put into service; and
it is just as well that such was the case, for in their construction
everything was sacrificed to speed of production. As a consequence they
are very ugly boats, with none of the fine lines of a destroyer, and
they roll badly, even when the sea is comparatively peaceful. They are
five-hundred-ton boats designed to make eighteen knots, which would not
have been fast enough to cope with U-boats, because the latter could
make as high a speed as that themselves, when traveling on the surface,
and the two 4-inch guns of the Eagles would have been far outranged by
the 5.9-inch guns of the larger U-boats.
SEAPLANE TOWING-BARGES
When the war on the U-boat was carried up into the sky, many new naval
problems cropped up, particularly when German submarines chose to work
far out at sea. Big seaplanes were used, but they consumed a great deal
of fuel in flying out and back, cutting down by just so much their
flying-radius at the scene of activities. A special towing-barge was
used. These barges had trimming-tanks aft, which could be flooded so
that the stern of the barge would submerge. A cradle was mounted to run
on a pair of rails on the barge. The body of the seaplane was lashed
to this cradle and then drawn up on the barge by means of a windlass.
This done, the water was blown out of the trimming-tanks by means of
compressed air and the barge was brought up to an even keel. The barge
with its load was now ready to be towed by a destroyer or other fast
boat to the scene of operations. There water was again let into the
trimming-tanks and the seaplane was let back into the water. From the
water the seaplane arose into the air in the usual way.
Unfortunately, when the sea is at all rough it is exceedingly difficult
for a seaplane to take wing, particularly a large seaplane. A better
starting-platform than the sea had to be furnished. At first some
seaplanes were furnished with wheels, so that they could be launched
from platforms on large ships; and then, to increase the flying-radius,
seaplanes were discarded in favor of airplanes. Once these machines
were launched, there was no way for them to get back to the ship. They
had to get back to land before their fuel was exhausted.
On the large war-vessels a starting-platform was built on a pair of
long guns. Then the war-ship would head into the wind and the combined
travel of the ship and of the airplane along the platform gave speed
enough to raise the plane off the platform before it had run the full
length of the guns. But as long as aviators had no haven until they
got back to land, there were many casualties. Eager to continue their
patrol as long as possible, they would sometimes linger too long
before heading for home and then they would not have enough fuel
left to reach land. Many an aviator was lost in this way, and finally
mother-ships for airplanes had to be built.
[Illustration: Courtesy of "Scientific American"
Electrically Propelled Boat or Surface Torpedo, Attacking a Warship,
under Guidance of an Airplane Scout]
THE "HUSH SHIPS"
The British Navy had constructed a number of very fast cruisers to deal
with any raiders the Germans might send out. These cruisers were light
vessels capable of such high speeds that they could even overtake a
destroyer. They were 840 feet long and their turbines developed 90,000
horse-power. The construction of these vessels was for a long time kept
a profound secret and it was not until the German fleet surrendered
that photographs of them were allowed to be published. Because of
this secrecy the boats were popularly known as "hush ships." They
were not armored; it was not necessary to load them down with armor
plate, because their protection lay in speed and they were designed
to fight at very long range. In fact, they were to carry guns that
would outrange those of the most powerful dreadnoughts. Our largest
naval guns are of 16-inch caliber, but the "hush ships" were each to
carry two _18-inch guns_. The guns were monsters weighing 150 tons
each and they fired a shell 18 inches in diameter and 7 feet long to
a distance of 30 miles when elevated to an angle of 45 degrees. The
weight of the shell was 3600 pounds and it carried 500 pounds of high
explosive or more than is carried in the largest torpedoes.
At the 32-mile range the shell would pass through 12 inches of
face-hardened armor and at half that range it would pass through armor
18 inches thick, and there is no armor afloat any heavier than this.
[Illustration: Courtesy of "Scientific American"
Hauling a Seaplane up on a Barge so that it may be Towed at High Speed
by a Destroyer]
MOTHER-BOATS FOR AIRPLANES
Armed with such powerful guns as these, the "hush ships" would have
been very formidable indeed; but when the guns were mounted on one
of the cruisers, the _Furious_, they were found too powerful for the
vessel. It was evident that the monsters would very seriously rack
their own ship. So the guns were taken off the cruiser and it was
turned into a mother-ship for airplanes. A broad, unobstructed deck
was built on the ship which provided a runway from which airplanes
could be launched, and this runway was actually broad enough to permit
airplanes to land upon it. Under the runway were the hangars in which
the airplanes were housed. Other "hush ships" were also converted into
airplane mother-boats and there were special boats built for this very
purpose, although they were not able to make the speed of the "hush
ships." One of these special boats had funnels that turned horizontally
to carry off the furnace smoke over the stern and leave a perfectly
clear flying-deck, 330 feet long.
TORPEDO-PROOF MONSTERS
As for the 18-inch guns, they were put to another use. Early in the war
the British had need for powerful shallow-draft vessels which could
operate off the Flanders coast and attack the coast fortifications that
were being built by the Germans. The ships that were built to meet this
demand were known as monitors, because like the famous "monitor" of our
Civil War they carried a single turret. These monitors were very broad
for their length and were very slow. At best they could make only seven
knots and in heavy weather they could not make more than two or three
knots.
To be made proof against torpedoes these boats were formed with
"blisters" or hollow rounded swells in the hull at each side which
extended out to a distance of twelve to fifteen feet. The blisters were
subdivided into compartments, so that if a torpedo struck the ship it
would explode against a blister at a considerable distance from the
real hull of the ship and the force of the explosion would be expended
in the compartments. The blisters were the salvation of the monitors.
Often were the boats struck by torpedoes without being sunk.
Unfortunately, this form of protection could not be applied to ordinary
vessels, because it would have interfered seriously with navigation.
The blisters made the monitors very difficult to steer and hampered the
progress of a ship, particularly in a seaway.
With ships such as these the British bombarded Zeebrugge from a
distance of twenty to twenty-five miles. Of course, the range had to be
plotted out mathematically, as the target was far beyond the horizon of
the ship, and the firing had to be directed by spotters in airplanes.
At first guns from antiquated battle-ships were used in the monitors;
then larger guns were used, until finally two of the monitors
inherited the 18-inch guns of the _Furious_. A single gun was mounted
on the after deck of each vessel and the gun was arranged to fire only
on the starboard side. No heavily armored turret was provided, but
merely a light housing to shelter the gun.
AN ELECTRICALLY STEERED MOTOR-BOAT
The British war-vessels that operated in the shallow waters off the
coast of Flanders were a constant source of annoyance to the Germans.
Because of the shallow water it was seldom possible for a submarine
to creep up on them. A U-boat required at least thirty-five feet of
water for complete submergence and it did not dare to attack in the
open. This led the Germans to launch a motor-boat loaded with high
explosive, which was steered from shore. The motor-boat carried a reel
of wire which connected it with an operator on shore. There was no
pilot in the boat, but the helm was controlled electrically by the man
at the shore station. As it was difficult for the helmsman to see just
what his boat was doing, or just how to steer it when it was several
miles off, an airplane flew high above it and directed the helmsman,
by radiotelegraphy, how to steer his boat. Of course, radiotelegraphy
might have been used to operate the steering-mechanism of the boat, but
there was the danger that the radio operators of the British might send
out disturbing waves that would upset the control of the motor-boat,
and so direct wire transmission was used instead. Fortunately, when the
Germans tried this form of attack, an alert British lookout discovered
the tiny motor-boat. The alarm was given and a lucky shot blew up the
boat with its charge before it came near the British vessel.