THE WHITEHEAD TORPEDO
How best to float a charge of explosives against the hull of an enemy’s
ship and there explode it is the great problem of torpedo warfare.
The spar-torpedo, that did such effective work in the Civil War, was
little more than a can of gunpowder on the end of a stick. This stick
or spar was mounted usually on the bow of a steam-launch, either
partially submerged, like the _David_, or boldly running on the surface
over log-booms and through a hail of bullets and grapeshot, as when
Lieutenant Cushing sank the Confederate ironclad _Albemarle_. Once
alongside, the spar-torpedo was run out to its full length, raised,
depressed, and finally fired by pulling different ropes. So small was
the chance of success and so great the danger to the launch’s crew that
naval officers and inventors all the world over sought constantly for
some surer and safer way.
Early in the sixties, an Austrian artillery officer attached to the
coast defenses conceived the idea of sending out the launch without a
crew. He made some drawings of a big toy boat, to be driven by steam or
hot air or even by clockwork, and steered from the shore by long ropes.
As it would have no crew, this boat could carry the explosives in its
hull, and the spars which were to project from it in all directions
would carry no torpedoes themselves but would serve to explode the
boat’s cargo of guncotton by firing a pistol into it, as soon as one of
the spars came into contact with the target. Before he could carry out
his ideas any further, this officer died and his plans were turned over
to Captain Lupuis of the Austrian navy. Lupuis experimented diligently
with surface torpedoes till 1864, but found that he would have to
discover some better steering-device than ropes from the shore and some
other motive-power than steam or clockwork. So he consulted with Mr.
Whitehead, the English manager of a firm of engine manufacturers at the
seaport of Fiume.
Whitehead gave the torpedo a fish-shaped hull, so that it could run
beneath instead of on the surface. For motive-power he used compressed
air, which proved much superior to either steam or clockwork. And by
improving its rudders, he enabled the little craft to keep its course
without the aid of guide-ropes from the shore. The chief defect of the
first Whitehead torpedoes, which were finished and tried in 1866, was
that they kept bobbing to the surface, or else they would dive too
deep and pass harmlessly under the target. To correct this defect,
Whitehead invented by 1868 what he called the “balance chamber.” Then,
as now, each torpedo was divided into a number of separate compartments
or chambers, and in one of these the inventor placed a most ingenious
device for keeping the torpedo at a uniform depth. The contents of the
balance-chamber was Whitehead’s great secret, and it was not revealed
to the public for twenty years.
The automobile or, as it was then called, the “submarine locomotive”
torpedo was now a practicable, though by no means perfected, weapon,
and the Austrian naval authorities gave it a thorough trial at Fiume
in 1868. Whitehead rigged up a crude ejecting tube on the bow of a
gunboat, and successfully discharged two of his torpedoes at a yacht.
The Austrian government promptly adopted the weapon, but could not
obtain a monopoly of it, for Whitehead was a patriotic Englishman.
The British admiralty invited him to England two years later, and
after careful trials of its own, induced the English government to buy
Whitehead’s secret and manufacturing rights for $45,000. Other nations
soon added “Whiteheads” to their navies, and in 1873 there was built in
Norway a large, fast steam launch for the express purpose of carrying
torpedoes and discharging them at an enemy. Every one began to build
larger and swifter launches, till they evolved the torpedo-boat and the
destroyer of to-day.
The torpedo itself has undergone a similar development in size and
efficiency. The difference between the Whiteheads of forty-five years
ago and those of to-day is strikingly shown in the following table:
BRITISH NAVAL TORPEDOES OF 1870
_Length, _Diameter, _Charge, _Range, _Speed,
Feet_ Inches_ Pounds_ Yards_ Knots_
Large 14 16 67 600 7.5
guncotton
Small 13 10.58 in. 14 18 200 8.5
dynamite
BRITISH NAVAL TORPEDOES OF 1915
Large 21 21 330 12,000 48
guncotton
Small 18 18 200 16,000 36
guncotton
The length of a large modern torpedo, it will be observed, is only
three inches less than that of Fulton’s famous submarine boat of 1801.
A Whitehead torpedo is really a small automatic submarine, steered and
controlled by the most ingenious and sensitive machinery, as surely as
if it were manned by a crew of Lilliputian seamen.
Projecting from the head is the “striker,” a rod which, when the
torpedo runs into anything hard, is driven back in against a detonator
or “percussion-cap” of fulminate of mercury. Just as the hammer of
a toy “cap-pistol” explodes a paper cap, so the sudden shock of the
in-driven striker explodes the fulminate, which is instantly expanded
to more than two thousand times its former size. This, in turn, gives a
severe blow to the surrounding “primer” of dry guncotton. The primer is
exploded, and by its own expansion sets off the main charge of several
hundred pounds of wet guncotton.
The reason for this is that though wet guncotton is safe to handle
because a very great shock is required to make it explode, dry
guncotton is much less so, while a shell or torpedo filled with
fulminate of mercury would be more dangerous to its owners than to
their enemies, because the slightest jar might set it off prematurely.
Every precaution is taken to prevent a torpedo’s exploding too soon and
damaging the vessel from which it is fired.
When the torpedo is shot out of the tube, by compressed air, like a pea
from a pea-shooter, the striker is held fast by the “jammer”: a small
propellor-shaped collar, whose blades begin to revolve as soon as they
strike the water, till the collar has unscrewed itself and dropped off
after the torpedo has traveled about forty feet. A copper pin that runs
through the striker-rod is not removed but must be broken short off by
a blow of considerable violence, such as would be given by running into
a ship’s hull. As a third safeguard, there is a strong safety-catch,
that must be released by hand, just before the torpedo is placed in the
tube.
The explosive charge of two or three hundred pounds of wet guncotton
is called the “war-head.” In peace and for target-practice it is
replaced by a dummy head of thick steel. The usual target is the space
between two buoys moored a ship’s length or less apart. At the end
of a practice run, the torpedo rises to the surface, where it can be
recovered and used again. This is distinctly worth while, for a modern
torpedo costs more than seven thousand dollars.
Back of the war-head is the air-chamber, that contains the motive-power
of this miniature submarine. The air is either packed into it by
powerful pumps, on shore or shipboard, or else drawn from one of the
storage flasks of compressed air, a number of which are carried on
every submarine. The air-chamber of a modern torpedo is charged at a
pressure of from 2000 to 2500 pounds per square inch. As the torpedo
leaves the tube, a lever on its back is struck and knocked over by
a little projecting piece of metal, and the starting-valve of the
air-chamber is opened. But if the compressed air were allowed to
reach and start the engines at once, they would begin to revolve the
propellors while they were still in the air inside the tube. This would
cause the screws to “race,” or spin round too rapidly and perhaps
break off. So there is a “delaying-valve,” which keeps the air away
from the engines till another valve-lever is swung over by the impact
of the water against a little metal flap.
As the compressed air rushes through the pipe from the chamber to the
engine-room, it passes through a “reducing-valve,” which keeps it from
spurting at the start and lagging at the finish. By supplying the air
to the engines at a reduced but uniform pressure, this device enables
the torpedo to maintain the same speed throughout the run. At the same
time the compressed air is heated by a small jet of burning oil, with a
consequent increase in pressure, power, and speed, estimated at 30 per
cent. All these devices are kept not in the air-chamber itself but in
the next compartment, the balance-chamber.
Here is the famous little machine, once a close-kept secret but now
known to all the world, that holds the torpedo at any desired depth.
Think of a push-button, working in a tube open to the sea, with the
water pressure pushing the button in and a spiral spring inside shoving
it out. This push-button--called a “hydrostatic valve”--is connected
by a system of levers with the two diving-planes or horizontal rudders
that steer the torpedo up or down. By turning a screw, the spring
can be adjusted to exert a force equal to the pressure of the water
at any given depth. If the torpedo dives too deep, the increased
water-pressure forces in the valve, moves the levers, raises the
diving-planes, and steers the torpedo towards the surface. As the water
pressure grows less, the spring forces out the valve, depresses the
diving-planes, and brings the miniature submarine down to its proper
depth again. When his torpedoes grew too big to be controlled by the
comparatively feeble force exerted by the hydrostatic valve, Whitehead
invented the “servo-motor”: an auxiliary, compressed-air engine, less
than five inches long, sensitive enough to respond to the slightest
movement of the valve levers but strong enough to steer the largest
torpedo, exactly as the steam steering-gear moves the huge rudder of an
ocean liner.
There is also a heavy pendulum, swinging fore and aft and attached to
the diving-planes, that checks any sudden up-or-down movement of the
torpedo by inclining the planes and restoring the horizontal position.
Next comes the engine-room, with its three-cylinder motor, capable of
developing from thirty-five to fifty-five horse-power. The exhaust air
from the engine passes out through the stern in a constant stream of
bubbles, leaving a broad white streak on the surface of the water as
the torpedo speeds to its mark.
The aftermost compartment is called the buoyancy chamber. Besides
adding to the floatability of the torpedo, this space also holds the
engine shaft and the gear attaching it to the twin propellors. The
first Whiteheads were single-screw boats. But the revolution of the
propellor in one direction set up a reaction that caused the torpedo
itself to partially revolve or heel over in the other, disturbing its
rudders and swerving it from its course. This reaction is neutralized
by using two propellers, one revolving to the right, the other to the
left. Instead of being placed side by side, as on a steamer, they are
mounted one behind the other, with the shaft of one revolving inside
the hollow shaft of the other, and in the opposite direction.
Long after they could be depended on to keep a proper depth, the
Whiteheads and other self-propelled torpedoes were liable to swing
suddenly to port or starboard, or even turn completely round. During
the war between Chile and Peru, in 1879, the Peruvian ironclad
_Huascar_ discharged an automobile torpedo that went halfway to the
target, changed its mind, and was coming back to blow up its owners
when an officer swam out to meet it and succeeded in turning it aside,
for the torpedoes of that time were slow and small as well as erratic.
Nowadays a torpedo is kept on a straight course by a gyroscope placed
in the buoyancy chamber. Nearly every boy knows the gyroscopic top,
like a little flywheel, that you can spin on the edge of a tumbler.
The upper part of this toy is a heavy little metal wheel, and if you
try to push it over while it is spinning, it resists and pushes back,
as if it were alive. A similar wheel, weighing about two pounds, is
placed in the buoyancy chamber of a Whitehead. When the torpedo starts,
it releases either a powerful spring or an auxiliary compressed air
engine that sets the gyroscope to spinning at more than two thousand
revolutions a minute. It revolves vertically, in the fore-and-aft line
of the torpedo, and is mounted on a pivoted stand. If the torpedo
deviates from its straight course, the gyroscope does not, and the
consequent change in their relative positions brings the flywheel into
contact with a lever running to the servo-motor that controls the two
vertical rudders, which soon set the torpedo right again.
[Illustration: Cross-section of a Whitehead Torpedo.
Redrawn from the Illustrated London News.
A, Striker which, when driven in, fires the charge; B, Safety
pin, which is removed just before the torpedo is discharged;
C, Detonating charge; D, Explosive-head, or war-head; filled
with guncotton; E, Primer charge of dry guncotton in cylinder;
F, Balance chamber; G, Starting pin; H, Buoyancy chamber;
I, Propellor shaft; J, Vertical rudder; K, Twin screws; L,
Horizontal rudder; M, Gyroscope controlling torpedo’s course;
N, Engines propelling machinery; O, Pendulum acting on the
horizontal rudder which controls the depth of submergence; P,
Hydrostatic valve; Q, Air-chamber, filled with compressed air;
provides motive-power for the engines; R, “Jammer” or release
propellor.
]
Thus guided and driven, a modern torpedo speeds swiftly and surely to
its target, there to blow itself into a thousand pieces, with a force
sufficient to sink a ship a thousand times its size.
The Whitehead is used by every navy in the world except the German,
which has its own torpedo: the “Schwartzkopf.” This, however, is
practically identical with the Whitehead, except that its hull is
made of bronze instead of steel and its war-head is charged with
trinitrotuluol, or T.N.T., a much more powerful explosive than
guncotton.
After the Russo-Japanese War, when several Russian battleships kept
afloat although they had been struck by Japanese torpedoes, many naval
experts declared that an exploding war-head spent most of its energy in
throwing a great column of water up into the air, instead of blowing
in the side of the ship. So Commander Davis of the United States navy
invented his “gun-torpedo.” This is like a Whitehead in every respect
except that instead of a charge of guncotton it carries in its head
a short eight-inch cannon loaded with an armor-piercing shell and a
small charge of powder. In this type of torpedo, the impact of the
striker against the target serves to fire the gun. The shell then
passes easily through the thin side of the ship below the armor-belt
and through any protecting coal-bunkers and bulkheads it may encounter,
till it reaches the ship’s vitals, where it is exploded by the delayed
action of an adjustable time-fuse. What would happen if it burst in
a magazine or boiler-room is best left to the imagination. Several
Davis gun-torpedoes have been built and used against targets with very
satisfactory results, but they have not yet been used in actual warfare.
[Illustration:
Courtesy of the Electric Boat Company.
Davis Gun-Torpedo after discharge, showing eight-inch gun forward of
air-flask.]
Mr. Edward F. Chandler, M.E., one of the foremost torpedo-experts in
America, is dissatisfied with the compressed-air driven gyroscope,
both because it does not begin to revolve till after the torpedo has
been launched and perhaps deflected from its true course, and because
it cannot be made to spin continuously throughout the long run of a
modern torpedo. He proposes to remove the compressed-air servo-motors,
both for this purpose and for controlling the horizontal rudders by
the hydrostatic valve, and replace them with an electrical-driven
gyroscope and depth-gear. The increased efficiency of the latter would
enable him to get rid of the heavy, uncertain pendulum, thus allowing
for the weight of the storage batteries. Mr. Chandler declares that
his electrically-controlled torpedo can be lowered over the side of a
small boat, headed in any desired direction, and started, without any
launching-tube.[9]
[Illustration:
Courtesy of the Electric Boat Company.
Effect of Davis Gun-Torpedo on a specially-constructed target.]
Though the automobile torpedo has been brought to so high a state
of perfection, the original idea of steering from the shore has not
been abandoned. The Brennan and Sims-Edison controllable torpedoes
were driven and steered by electricity, receiving the current through
wires trailed astern and carrying little masts and flags above the
surface to guide the operator on shore. But these also served as a
warning to the enemy and gave him too good a chance either to avoid the
torpedo or destroy it with machine-gun fire. Then, too, the trailing
wires reduced its speed and were always liable to get tangled in the
propellors. Controllable torpedoes of this type were abandoned before
the outbreak of the present war and will probably never be used in
action.
A new and more promising sort of controllable torpedo was immediately
suggested by the invention of wireless telegraphy. Many inventors have
been working to perfect such a weapon, and a young American engineer,
Mr. John Hays Hammond, Jr., seems to have succeeded. From his wireless
station on shore, Mr. Hammond can make a small, crewless electric
launch run hither and yon as he pleases about the harbor of Gloucester,
Massachusetts. The commander and many of the officers of the United
States coast artillery corps have carefully inspected and tested this
craft, which promises to be the forerunner of a new and most formidable
species of coast defense torpedo.