A TRIP IN A MODERN SUBMARINE
Lieutenant Perry Scope, commanding the X-class flotilla, was sitting
in his comfortable little office on the mother-ship _Ozark_, when
I entered with a letter from the secretary of the navy, giving me
permission to go on board a United States submarine. Without such
authorization no civilian may set foot on the narrow decks of our
undersea destroyers, though he may visit a battleship with no more
formality than walking into a public park.
“We’re too small and full of machinery to hold a crowd,” explained the
lieutenant, “and the crowd wouldn’t enjoy it if they came. No nice
white decks for the girls to dance on or fourteen-inch guns for them
to sit on while they have their pictures taken. Besides, everything’s
oily--you’d better put on a suit of overalls instead of those white
flannels.”
There were plenty of spare overalls on the _Ozark_, for she was the
mother-ship of a family of six young submarines. Built as a coast
defense monitor shortly after the Spanish War, she had long since been
retired from the fighting-line, and was now the floating headquarters,
dormitory, hospital, machine-shop, bakery, and general store for the
six officers and the hundred and fifty men of the flotilla.
[Illustration:
Photo by Brown Bros.
U. S. Submarine _E-2_.
Note wireless, navigating-bridge, and openings for flooding
superstructure when submerging.]
Moored alongside the parent-ship, the submarine _X-4_ was filling her
fuel-tanks with oil through a pipe-line, in preparation for the day’s
cruise and target-practice I was to be lucky enough to witness. Two
hundred and fifty feet long, flat-decked and straight-stemmed, she
looked, except for the lack of funnels, much more like a surface-going
torpedo-boat than the landsman’s conventional idea of a submarine.
“I thought she would be cigar-shaped,” I said as we went on board.
“She is--underneath,” answered Lieutenant Scope. “What you see is only
a light-weight superstructure or false hull built over the real one.
See those holes in it, just above the water line? They are to flood the
superstructure with whenever we submerge, otherwise the water pressure
would crush in these thin steel plates like veneering. But it makes
us much more seaworthy for surface work, gives us a certain amount of
deckroom, and stowage-space for various useful articles, such as this.”
Part of the deck rose straight up into the air, like the top of a
freight-elevator coming up through the sidewalk. Beneath the canopy
thus formed was a short-barreled, three-inch gun.
“Fires a twelve-pound shell, like the field-pieces the landing-parties
take ashore from the battleships,” explained the naval officer, as
he trained the vicious-looking little cannon all around the compass.
“Small enough to be handy, big enough to sink any merchant ship afloat,
or smash anything that flies.”
Here he pointed the muzzle straight up as if gunning for hostile
aeroplanes.
“And please observe,” he concluded, as the gun sank down into its
lair again, “how that armored hatch-cover protects the gun-crew from
shrapnel or falling bombs.”
I followed him to the conning-tower, or, as he always spoke of it,
the turret. The little round bandbox of the _Holland_ has developed
into a tall, tapering structure, sharply pointed fore and aft to
lessen resistance when running submerged. Above the turret was a small
navigating-bridge, screened and roofed with canvas, where a red-haired
quartermaster stood by the steering-wheel, and saluted as we came
up the ladder. The lieutenant put the engine-room telegraph over to
“Start,” and a mighty motor throbbed underneath our feet. Then the
mooring was cast off, the telegraph put over to “Slow Ahead,” and the
_X-4_ put out to sea.
“How long a cruise could she make?” I asked.
“Four thousand miles is her radius,” answered her commander. “Back in
1915, ten American-designed submarines crossed from Canada to England
under their own power.”
“Yet it is only a few years since we were told that submarines could
only be used for coast defense, unless they were carried inside their
mother-ships and launched near the scene of battle,” I remarked. “Or
that each battleship should carry a dinky little submarine on deck and
lower it over the side like a steam-launch.”
“People said the same thing about torpedo-boats,” agreed the
lieutenant; “they began as launches--now look at the size of that
destroyer smoking along over there. Ericsson thought that any ironclad
bigger than a Civil War monitor would be an unwieldy monster. Even
John P. Holland fought tooth and nail against increasing the length of
his submarines. This boat of mine is five times the length of the old
_Holland_, but she’s only a primitive ancestor of the perfect submarine
of the future.”
“She isn’t a submarine at all,” I replied presently, as the _X-4_ swept
on down the coast at a good twenty-two knots, her foredeck buried in
foam and the sea-breeze singing through the antennæ of her wireless.
“She’s nothing but a big motor-boat.”
“And she’s got some big motors,” replied the lieutenant. “Better step
below and have a look at them.”
I went down through the open hatchway to the interior of the boat
and aft to the engine-room. There I found two long, many-cylindered
oil-engines of strange design, presided over by a big blond engineer
whose grease-spotted dungarees gave no hint as to his rating.
“What kind of machines are these?” I shouted above the roar they made.
“And why do you need two of them?”
“Diesel heavy-oil engines,” he answered. “One for each propeller.”
“What is the difference between one of these and the gasoline engine of
a motor-car? I know a little about that.”
“Do you know what the carburetor is?” asked the engineer.
[Illustration:
Courtesy of International Marine Engineering.
A Submarine Cruiser, or Fleet Submarine (Lake Type).
The parts indicated by numbers in this illustration are as follows:
1, main ballast tanks; 2, fuel tanks; 3, keel; 4, safety drop
keel; 5, habitable superstructure; 6, escape and safety chambers;
7, disappearing anti-air craft guns; 8, rapid fire gun; 9,
torpedo tubes; 10, torpedoes; 11, twin deck torpedo tubes; 12,
torpedo firing tank; 13, anchor; 14, periscopes; 15, wireless;
16, crew’s quarters; 17, officers’ quarters; 18, war-head
stowage; 19, torpedo hatch; 20, diving chamber; 21, electric
storage battery; 22, galley; 23, steering gear; 24, binnacle; 25,
searchlight; 26, conning-tower; 27, diving station; 28, control
tank; 29, compressed air flasks; 30, forward engine room and
engines; 31, after engine room and engines; 32, central control
compartment; 33, torpedo room; 34, electric motor room; 35,
switchboard; 36, ballast pump; 37, auxiliary machinery room; 38,
hydroplane; 39, vertical rudders; 40, signal masts.
]
“That’s where the gasoline is mixed with air, before it goes into the
cylinder.”
The engineer nodded.
“The mixture is sucked into the cylinder by the down-stroke of the
piston. The up-stroke compresses it, and then the mixture is exploded
by an electric spark from the spark-plug. The force of the explosion
drives the piston down, and the next stroke up drives out the refuse
gases. That’s how an ordinary, four-cycle gasoline motor works.
“But the Diesel engine,” he continued, “doesn’t need any carburetor
or spark-plug. When the piston makes its first upward or
compression-stroke, there is nothing in the cylinder but pure air. This
is compressed to a pressure of about 500 pounds a square inch--and when
you squeeze anything as hard as that, you make it mighty hot--”
“Like a blacksmith pounding a piece of cold iron to a red heat?” I
suggested. The engineer nodded again.
“That compressed air is so hot that the oil which has been spurted in
through an injection-valve is exploded, and drives the piston down on
the power-stroke. The waste gases are then blown out by compressed air.
There are an air-compressor and a storage tank just for scavenging, or
blowing the waste gases out of every three power-cylinders.”
“What are the advantages of the Diesel over the gasoline engine?”
[Illustration:
Courtesy of the Electric Boat Company.
Auxiliary Switchboard and Electric Cook-stove, in a U. S. Submarine.]
“In the first place, it gives more power. You see, three out of every
four strokes made by the piston of a gasoline engine--suction-stroke,
compression-stroke, and scavenging-stroke--waste power instead of
producing it. But the Diesel is what we call a two-cycle engine; its
piston makes only two trips for each power-stroke. In the second
place, it is cheaper, because instead of gasoline it uses heavy,
low-price oil. And this makes it much safer, for the heavy oil does
not vaporize so easily. The air in some of the old submarines that
used gasoline motors would get so that it was like trying to breathe
inside a carburetor, and there was always the chance of a spark from
the electric motors exploding the whole business, and your waking up to
find the trained nurse changing your bandages. The German navy refused
to build a submarine as long as there was nothing better than gasoline
to propel it on the surface. They didn’t launch their _U-1_ till
1906, after Dr. Diesel had got his motor into practicable shape. It
cost him twenty years of hard work, but without his motor we couldn’t
have the modern submarine. And they’re using it more and more in ocean
freighters. There’s a line of motor-ships running to-day between
Scandinavia and San Francisco, through the Panama Canal.
“Aft of the Diesel, here,” continued the engineer, “is our electric
motor, for propelling her when submerged. Reverse it and have it driven
by the Diesel engine, and the motor serves as a dynamo to generate
electricity for charging the batteries. As long as we can get oil and
come to the surface to use it, we can never run short of ‘juice.’[14]
“Besides turning the propeller, the electricity from the batteries
lights the boat, and turns the ventilating fans, works the
air-compressor for the torpedo-tubes, drives all the big and little
pumps, runs a lot of auxiliary motors that haul up the anchor, turn the
rudders, and do other odd jobs, it heats the boat in cold weather--”
“And cooks the grub all the year round, don’t forget that, Joe,” said
another member of the crew. “Luncheon is served in the palm room.”
We ate from a swinging table let down from the ceiling of the main- or
living-compartment of the submarine, that extended forward from the
engine-room to the tiny officers’ cabin and the torpedo room in the
bows. Tiers of canvas bunks folded up against the walls showed where
the crew slept when on a cruise. For lunch that day we had bread baked
on the mother-ship, butter out of a can, fried ham, fried potatoes,
and coffee hot from a little electric stove such as you can see
in the kitchenette of a light-housekeeping apartment on shore. The
lieutenant’s lunch was carried up to him on the bridge. When the meal
was over, most of the men went on deck, and my friend the engineer put
a large cigar in his mouth. I took out a box of matches and was about
to strike one for his benefit when he stopped me, saying,
“Don’t ever strike a light in a submarine or a dynamite factory. It’s
unhealthy.”
[Illustration:
Courtesy of the Electric Boat Company.
Forward deck of a U. S. Submarine, in cruising trim.]
I apologized profusely.
“The air is so much better than I had expected that I forgot where I
was.”
“Yes,” said the engineer, chewing his unlighted cigar, “there is plenty
of good air in a big modern boat like this, running on the surface in
calm weather and with the main hatch and all ventilators open. But
come with us when we’re bucking high seas or running submerged on a
breathing-diet of canned air flavored with oil, and you’ll understand
why so many good men have been invalided out of the flotilla with
lung-trouble. We’re the only warships without any dogs or parrots
or other mascots on board, for no animal could endure the air in a
submarine.”
[Illustration:
Courtesy of the Electric Boat Company.
Same, preparing to submerge. Railing stowed away and bow-rudders
extended.]
“I thought every submarine carried a cage of white mice, because they
began to squeak as soon as the air began to get bad and so warned the
crew.”
“That was a crude device of the early days,” replied the engineer. “We
don’t carry white mice any more, though I believe they still use them
in the British navy.”
I went up on deck, to find that the _X-4_ had reached the
practice-grounds and was being made ready for a dive. Her crew
were busy dismantling and stowing away the bridge and the light
deck-railing, hauling down the flag, and closing all ventilators and
other openings.
“How long has it taken you to get ready?” I asked Lieutenant Scope.
“Twenty minutes,” he answered. “But the real diving takes only two
minutes. We’ll go below now, sink her to condition, and run her under
with the diving rudders.”
“What are those things unfolding themselves on either side of the
bows?” I asked. “I thought the diving rudders were carried astern.”
“Modern submarines are so long that they need them both fore and aft,”
replied the lieutenant. “As you see, the diving rudders fold flat
against the side of the boat where they will be out of harm’s way when
we are running on the surface or lying alongside the mother-ship.
Better come below now, for we’re going to dive.”
We descended into the turret and the hatch was closed. The Diesel
engines had already been stopped and the electric motors were now
turning the propellers.
“Why are those big electric pumps working down there?” I asked.
“Pumping water into the ballast-tanks.”
“But doesn’t the water run into the tanks anyhow, as soon as you open
the valves?” I asked the lieutenant.
“Turn a tumbler upside down and force it down into a basin of water,”
he replied, “and you trap some air in the top of the tumbler, which
prevents the water from rising beyond a certain point. The same thing
takes place in our tanks, and to fill them we have to force in the
water with powerful pumps that compress the air in the tanks to a very
small part of its original bulk. This compressed air acts as a powerful
spring to drive the water out of the tanks again when we wish to rise.
By blowing out the tanks, a submarine can come to the surface in twenty
seconds or one sixth the time it takes to submerge.”
“When are we going under?” I asked him. The lieutenant looked at his
watch and answered,
“We have been submerged for the last four minutes.”
I experienced a feeling of the most profound disappointment. Ever since
I had been a very small boy I had been looking forward to the time when
I should go down in a submarine boat, and now that time had passed
without my realizing it.
“But why didn’t I feel the boat tilt when she dived?” I demanded.
“Because she went down a very gentle slope, between two and three
degrees at the steepest. The only way you could have noticed it would
have been to watch these gages.”
Large dials on the wall of the turret indicated that the _X-4_ was
running on what was practically an even keel at a depth of sixteen feet
and under a consequent water-pressure of 1024 pounds on every square
foot of her hull.
“How deep could she go?”
“One hundred and fifty feet--if she had to. The strong inner hull of a
modern submarine is built up of three quarter inch plates of the best
mild steel and well braced and strengthened from within. But as a rule
there is no need of our diving below sixty feet at the deepest, or far
enough to clear the keel of the largest ship. You will notice how the
depth-control man is holding her steady by manipulating the forward
horizontal rudders, just as an aviator steadies his aeroplane.”
[Illustration:
Courtesy of the Electric Boat Company.
Depth-control Station, U. S. Submarine.
Wheel governing horizontal rudders, gages showing depth, trim, etc.]
“He must be a strong man to handle those two big horizontal rudders.”
“He has an electric motor to do the hard work for him, as has the
quartermaster steering the course here with the vertical rudder.”
The same red-headed petty officer that I had noticed on the bridge now
grasped the spokes of a smaller steering-wheel inside the conning-tower.
“What is that queer-looking thing whirling round and round in front of
him?” I asked.
“A Sperry gyroscopic compass,” replied the lieutenant. “An ordinary
magnetic compass could not be relied on to point in any particular
direction if it was shut up in a steel box full of charged electric
wires, like the turret of a submarine. We tried to remedy this by
building conning-towers of copper, till Mr. Sperry perfected a compass
that has no magnetic needle, but operates on the principle of the
gyroscope. You know that a heavy, rapidly rotating wheel resists any
tendency to being shifted relative to space?”
“Yes.”
[Illustration: Cross-section of a Periscope.]
“The earth, revolving on its axis, is nothing but a big gyroscope--that
is why it stays put. The little gyroscope on this compass spins at
right angles to the revolution of the earth and so keeps in a due north
and south line. But the frame it is mounted on turns with the ship,
so the relative positions of the frame and the gyro-axis show in what
direction the submarine is heading.”
“And you can see what’s ahead of you through the periscope. Who
invented that?”
“The idea is a very old one. Certain French and Dutch inventors
designed submarines with periscopes as long ago as the eighteen-fifties.
In the Civil War, the light-draft river-monitor _Osage_ had attached to
her turret a crude periscope made by her chief engineer, Thomas Doughty,
out of a piece of three-inch steam-pipe with holes cut at each of its
ends at opposite sides, and pieces of looking-glass inserted as
reflectors. By means of this instrument her captain, now Rear-Admiral,
Thomas O. Selfridge, was able to look over the high banks of the Red
River when the _Osage_ had run aground in a bend and was being attacked
by three thousand dismounted Confederate cavalry, who were repulsed with
the loss of four hundred killed or wounded by the fire of the monitor’s
11-inch guns, directed through the periscope.[15]
“But as late as 1900 the periscope was so crude and unsatisfactory an
instrument that John P. Holland would have nothing to do with it. The
credit for bringing it to its present efficiency belongs chiefly to
the Germans, who kept many of their scientists working together on the
solution of the difficult problems of optics that were involved.
“By turning this little crank,” the lieutenant continued, “I can
revolve the reflector at the top of the tube. This reflector contains
a prism which reflects the image of the object in view down through a
system of lenses in the tube to another prism here at the bottom, where
the observer sees it through an eyepiece and telescope lenses.”
I looked into the eyepiece, which was so much like that of an
old-fashioned stereoscope that I felt that it, too, ought to work back
and forth after the manner of a slide trombone. I found myself looking
out over the broad blue waters of a sunlit bay. I noticed a squall
blackening the surface of the water, a catboat running before it, and
the gleam of the brass instruments of the band playing on the after
deck of a big white excursion steamer half a mile away.
“I can almost imagine I can hear the music of that band,” I exclaimed.
“The optical illusion is perfect.”
“It has to be,” rejoined the lieutenant. “If the image were in the
least distorted or out of perspective, we couldn’t aim straight.”
“What do you do when the periscope is wet with spray?” I asked him.
“Wash the glass with a jet of alcohol and dry it from the inside with
a current of warm air passing up and down the tube. A periscope-tube
is double: the outer one passing through a stuffing-box in the hull,
and the inner tube revolving inside it. The old-fashioned single tubes
were too hard to revolve and the resistance of the water used to bend
them aft and cause leakage. We can raise and lower the periscopes at
will, and all our larger boats have two of them, so that they can keep
a lookout in two directions at once, besides having a spare eye in case
the first is put out.”
“What are those two little things that big naval tug is towing over
there?” I inquired.
“The target for our torpedo practice,” replied Lieutenant Scope. “We
shall try to put four Whiteheads between those two buoys as the tug
tows them past at an unknown range and speed. If you step forward to
the torpedo room you can see them loading the tubes.”
As I walked forward it occurred to me that the twenty-odd men on board
the _X-4_ seemed to be moving about inside her with perfect freedom,
without disturbing her trim. I mentioned this to one of the crew.
[Illustration:
Courtesy of the Electric Boat Company.
Forward torpedo-compartment, U. S. Submarine, showing
breech-mechanism of four tubes. Round opening above is the
escape-hatch.
]
“It’s the trimming-tanks that keep her level,” he explained. “As we’re
walking forward, our weight in water is being automatically pumped from
the trimming-tank in the bow to the one astern. A submarine is just one
blamed tank after another. Stand clear of that chain-fall, sir; they’re
loading No. 1 tube.”
Stripped to the waist like an old-time gun-crew, four beautifully
muscled young gunner’s mates were hoisting, with an ingenious
arrangement of chains and pulleys, a torpedo from the magazine. The
breach of the tube was opened and the long Whitehead thrust in, two
flanges on its sides being fitted into deep grooves in the sides of
the tube, so that the torpedo would not spin like a rifle-bullet but be
launched on an even keel. The breach was closed, and the men stood by
expectantly.
“Skipper’s up in the conning-tower, taking aim through the periscope,”
explained the man who had told me about trimming-tanks. “The tubes
being fixed in the bow, he has to train the whole boat like a gun.
Likewise he’s got to figure out how far it is to the target and how
fast the tug is towing it, how many seconds it’s going to take the
torpedo to get there, and how much he’s got to allow for its being
carried off its course by tide and currents. When he gets good and
ready, the lieutenant’ll press a little electric button and you’ll
hear--”
“THUD!” went the compressed air in the tube, and the submarine
shuddered slightly with the shock of the recoil. But that was all.
“There she goes!” said my friend the tank-expert. “As soon as the
Whitehead was expelled, a compensation-tank just above the tube was
flooded with enough water to make good the loss in weight.”
“What keeps the sea-water from rushing into the tube after the torpedo
leaves it?” I asked.
“A conical-shaped cap on the bow of the boat keeps both tubes closed
except when you want to fire one of them. Then the cap, which is
pivoted on its upper edge, swings to port or starboard just long enough
for the torpedo to get clear and swings back before the water can get
in.”
Four of the ten torpedoes carried in the magazine were sped on their
way to the unseen target. I returned to the turret as the wireless
operator entered and handed a typewritten slip to Lieutenant Scope, who
smiled happily and said to me,
“The captain of the tug reports that all four shots were hits and all
four torpedoes have been safely recovered.”
I was too astonished to congratulate him on his marksmanship, as I
should have done.
“How in the name of miracles!” I gasped. “Can you receive a wireless
telegram under the sea?”
“By the Fessenden oscillator,” he replied, and added to the wireless
man,
“Take this gentleman below and show him how it works.”
“Did you ever have another chap knock two stone together under water
when you were taking a dive?” asked the operator. I nodded in vivid
recollection.
“Then you have some idea how sounds are magnified under water. It is an
old idea to put submarine bells down under lighthouses and fit ships
with some kind of receiver so that the bells can be heard and warning
given when it is too foggy to see the light. The advantage over the
old-style bell-buoy lies in the fact that sound travels about four
times as fast through water as through air,[16] and goes further and
straighter because it isn’t deflected by winds or what the aviators
call ‘air-pockets.’ The man who knows most about these things is
Professor Fessenden, of the Submarine Signal Company of Boston, who
first realized the possibility of telegraphing through water.[17]
[Illustration:
Courtesy of the American Magazine.
Fessenden oscillator outside the hull of a ship. The “ear” of a modern
vessel.]
“Fastened outside the hull of this boat is one of the Fessenden
oscillators: a steel disk eighteen inches in diameter, that can be
vibrated very rapidly by electricity. These vibrations travel through
the water, like wireless waves through the ether, till they strike the
oscillator on another vessel and set it to vibrating in sympathy. To
send a message, I start and stop the oscillator with this key so as
to form the dots and dashes of the Morse code. To receive, I sit here
with these receivers over my ears and ‘listen in,’ just like a wireless
operator, till I pick up our call ‘X-4,’ ‘X-4.’”
“How far can you send a message under water?”
“Ten miles is the furthest I’ve ever sent one. Professor Fessenden has
sent messages more than thirty miles. The invention only dates back to
1913 and what it will do in the future, there is no telling.”
[Illustration:
Courtesy of the American Magazine.
Professor Fessenden receiving a message sent through several miles of
sea-water by his “Oscillator.”]
“Even now, couldn’t a surface vessel act as eyes for a whole flotilla
of submarines and tell them where to go and when to strike by coaching
them through the Fessenden oscillator?”
The operator nodded.
“We’re doing it to-day, in practice. But don’t forget that an enemy’s
ship carrying a pair of oscillators can hear a submarine coming two
miles away. You can make out the beat of a propeller at that distance
every time.”
“But how can you tell how far away and in what direction it is?”
“I can’t, with a single oscillator like ours. But a ship carries two
of them, one on each side of the hull, like the ears on a man’s head.
And just as a man knows whether a shout he hears comes from the right
or left, because he hears it more with one ear than the other, so the
skipper of a surface craft can look at the indicator that registers the
relative intensity of the vibrations received by the port and starboard
oscillators and say,
“‘There’s somebody three points off the starboard bow, mile and three
quarters away, and heading for us. Nothing in sight, so it must be one
of those blamed submarines.’
“And away he steams, full speed ahead and cutting zigzags. Or maybe
he gets his rapid-fire guns ready and watches for Mr. Submarine to
rise--like the _X-4_’s doing now.”
Freed of the dead weight of many tons of sea water blown from her
ballast-tanks by compressed air, the submarine rose to the surface like
a balloon. Ventilators and hatch-covers were thrown open and we swarmed
up on deck to fill our grateful lungs with the good sea air. Three
motor-boats from the tug throbbed up alongside with the four torpedoes
we had discharged.
“Those boats wait, one this side of the target, one near it and the
third over on the far side, to mark the shots and catch the torpedoes
after they rise to the surface at the end of their run,” said
Lieutenant Scope. “We very seldom lose a torpedo nowadays. They tell a
story about one that dived to the bottom and was driven by the force of
its own engines into forty feet of soft mud, where it stayed till it
happened to be dug up by a dredger.”
The four torpedoes were hoisted aboard, drained of the sea water that
had flooded their air-chambers, cleaned and lowered through the torpedo
hatch forward down into the magazine. By this time the bridge and
railing were again in place and the flags fluttering over the taffrail
as the _X-4_, her day’s work done, sped swiftly up the coast to home
and mother-ship.