TORPEDOES.
The torpedoes used by and against the different navies of the world may
be classed under two general heads, viz., offensive and defensive.
Offensive torpedoes may be classified in accordance with the manner in
which they are used, as Locomotive, Towing, Spar, and Drifting.
LOCOMOTIVE TORPEDOES.
_The Whitehead Torpedo._
The Whitehead torpedo consists of a projectile, or more properly
speaking a boat, containing a heavy explosive charge, an engine driven
by compressed air, screw propellers, and mechanism for regulating the
speed, depth of flotation, distance of run, and security of firing
arrangements. The general exterior appearance of the torpedo is that of
a spindle of revolution, its greatest diameter being in the middle and
the lines being so curved as to present a surface of minimum resistance
to the water. The dimensions of the torpedo range from fourteen feet
in length by sixteen inches in diameter to nineteen feet by seventeen
inches. The speed ranges from seven knots for a distance of eight
hundred yards up to twenty-five and a quarter knots for two hundred
yards, the most powerful combination being fifteen and a half knots for
one thousand yards.
[Illustration: Whitehead Torpedo and Firing-Tube.]
This torpedo, if adjusted to run at any desired depth of water of
from five to fifteen feet, and if it be projected from either above
water, at the water-line, or below the surface, will rapidly attain the
desired depth and maintain it throughout the run. If fired in still
water, it will make a straight run in the line of projection, allowance
being made for the sweep of currents. It can be adjusted to stop after
having run any distance up to its extreme range, and after stopping, it
will sink, float, or explode as desired.
The gun-cotton charge is placed in what is termed a cartridge-case,
which is a wooden case similar in shape to the forward section of the
torpedo, somewhat smaller, and held in place in its compartment by
wooden wedges. This charge is ignited mechanically, the arrangement
being as follows: Extending from the nose of the torpedo to the
cartridge-case is a tube terminating in a copper case, in which is
placed the priming charge and the detonating composition; within the
tube is a steel rod, two feet long, fitted with a needle-point at its
inner end and having its outer end screwed into a frame; this frame is
capable of moving in and out, and is connected with a spiral spring
which tends to force it, and consequently the steel rod, inwards,
the action being similar to that of the firing-pin of breech-loading
small-arms. By compressing this spiral spring, the inner end of the
frame is brought forward to a catch and held retracted. If now this
catch is disengaged in any manner, the rod flies back, acting like an
ordinary firing-pin on the detonating composition. The extreme forward
point of the torpedo, called the nose-piece, is so fitted that it is
capable of being forced inwards, but in a position of rest its inner
edge is just clear of the catch. This nose-piece is provided with short
horizontal and vertical arms, so as to insure good contact with the
body struck. The collision of the nose-piece against any resisting
body forces it back and releases the firing-pin. In order to secure
against accident, the nose-piece is provided with a safety-wedge and
key. Before discharging the torpedo the key is removed, and after the
discharge the wedge is withdrawn by the action of mechanism, and is
so arranged that it may be replaced automatically and thus disarm the
torpedo after its run, in case it is desired to recover it.
The arrangement for adjusting the length of range and for drawing and
replacing the wedge is as follows: Two cog-wheels, a large one and a
small one, are fixed on the upper part of the after-end of the torpedo,
just in front of the propellers. The small wheel has thirty teeth,
gearing in an endless screw attached to the propeller-shaft, and of
such a pitch that one revolution of the propeller moves the wheel one
tooth. The big cog-wheel is so arranged as to move one tooth for each
revolution of the small wheel. In front of this gearing is a small
stud that works fore and aft in a slot, being provided with a spring
which tends to force it towards the after-end of the slot. This stud
is connected by a rod to the valve which admits the compressed air to
the cylinders of the engine. When the stud is in the forward part of
the slot the valve is open, in the after part it is closed. By means
of a lever the spring of the stud is compressed, and the stud is moved
to the fore part of its slot; the big wheel is then moved around until
a stud on its face is the desired number of teeth above the lever. Now
for every thirty revolutions of the propeller, or one tooth of the big
wheel, a certain known distance is travelled, varying according to the
pattern of the torpedo, slip, etc. When the propeller has made the
number of revolutions corresponding to the desired length of range,
the stud on the big wheel presses against the lever of the spring
and releases the latter, forcing the valve-rod back and closing the
valve. Attached to the axle of the big wheel is a small brass arm which
is connected by means of a brass rod to the safety-wedge, and is so
arranged that after any required number of revolutions of the propeller
the safety-wedge will be drawn out; or it may be drawn out at the
instant of discharge. By means of an additional lever at the fore port
of the torpedo, which is connected by means of a rod to the valve of
the engine, and by arranging the attachment of the safety-wedge to the
brass rod from the big wheel so that on the wedge being withdrawn it
is released from the brass rod, the action of the closing of the valve
after the run of the torpedo is completed, forces the wedge into its
securing position again.
Naturally the torpedo would float at the end of its run from its
difference of buoyancy, owing to the compressed air used in working the
engines.
To sink the torpedo at the end of its run, a spiral-spring valve is
placed in the after wall of the adjustment chamber, which can be
attached to the brass rod working the engine-valve in such a way that
when the latter valve is closed the spring-valve is opened, admitting
water to the chamber and thus sinking the torpedo. If it is desired to
explode the torpedo at the end of the run, the nose-piece is connected
to the engine-valve, which, on closing, draws it violently back and
releases the firing-pin. To adjust the depth of flotation, a small
wheel, the face of which is marked in feet, is placed in the adjustment
chamber, and is turned by means of a key until the number of feet
desired comes under a pointer.
The secret of the Whitehead is in the mechanism by which the torpedo
maintains a desired depth. The adjustment chamber, which is next abaft
the explosion chamber, is connected by screw to the forward and after
chambers in such a manner that by means of a number of small holes
bored around the circumference the faces of the chamber are exposed
to the pressure of the outside water, which varies with the depth to
which the torpedo descends. Within the adjustment chamber is an endless
strong spiral spring, attached to the after face of the chamber,
and so arranged that after being set to a certain tension, capable
of resisting an equivalent pressure on the outside of the face, any
increase or decrease in this pressure will cause this spring to work
a rod by which the horizontal rudders of the torpedo are regulated.
Within this adjustment chamber is also placed an automatic balance,
which assists in maintaining the torpedo at the desired depth by
swinging forward on the torpedo’s descending or aft on ascending, and
thus assisting the rudders.
The Whitehead may be discharged through a submerged tube in the stern
or in broadside, from a carriage above the water-line, or from the
surface.
For discharging under water a tube is fitted to an orifice in the stern
or broadside, closed by a water-tight valve; the inner end is closed by
a water-tight door. The torpedo, being prepared, is placed in the tube,
the door is shut, water is admitted to the interior, and the valve is
opened. The torpedo is then shot out and started by means of a piston
bearing against its rear end and worked by compressed air. To prevent
it from slipping out before the time, a stop is provided at the forward
end of the tube, which is removed automatically at the same time that
the compressed air is admitted to the piston. In the case of broadside
discharge, the tube works inside an iron casing, through a stuffing-box
at the inner end and in a shield at the outer end. The shield, placed
on the forward side of the orifice, is of such a length as to protect
the torpedo from the pressure of the water passing the vessel.
In projecting from above water, an iron carriage is used, which is
fitted with a frame in which the torpedo rests. The outer end of this
frame is provided with a lip a few feet long, by means of which the
rear end of the torpedo is slightly canted up on leaving the frame,
preventing undue strain on the extreme end. The frame is mounted in
the carriage in such a way that it can be elevated or depressed by
means of a screw, like a gun. The torpedo is ejected by means of a
piston as before, the carriage being provided with a small reservoir of
compressed air so that it may be moved to any point aboard ship.
To project from the surface, no tube is necessary; all that is required
is to set it for the depth, point it, and turn back the lever by hand,
when it starts off of its own accord.
For discharging from boats, the torpedo is either mounted on its
carriage forward or carried in iron slings suspended from davits. In
the latter case the davits are pivoted, so that normally the torpedo
rests in a cradle on deck; but the cradle being removed, the davits are
swung over, lowering it to about two feet below water, where it is held
securely until discharged.
The propeller is worked by means of a pair of Brotherhood engines,
working to 60 indicated horse-power and giving 1000 revolutions a
minute. Weight of charge, 33 lbs. gun-cotton; weight of torpedo, 500
lbs.
THE LAY TORPEDO.
The shape of the Lay torpedo is quite similar to that of the Whitehead,
although it is considerably larger. As in the Whitehead, the forward
section forms the explosion chamber. Next abaft this is a chamber for
holding the gas reservoirs, carbonic-acid gas being the motive power.
Next aft is the compartment for holding an electrical cable, which
forms a constant connection between the torpedo and the operator. In
rear of this is the compartment for the engines and steering apparatus.
These sections are separated from each other by water-tight bulkheads.
The torpedo is propelled by double screws, the propellers working in
opposite directions and being placed one abaft the other, the shaft of
the forward one being hollow and that of the after one passing through
it. The torpedo has four horizontal fins or wings, two forward and two
aft; these wings are mounted on shafts or spindles passing transversely
through the boat. A guide-rod or short staff is provided at each end
of the torpedo to enable the operator to regulate the course. At night
lanterns are hung on these rods. The electrical cable, made up of two
insulated wires, is wound on a reel, and pays out through a hole in
the bottom of the compartment as the boat advances. By means of one of
these wires the boat is started, stopped, and steered, and by the other
it is fired.
[Illustration: Lay Torpedo.]
A double steering-rudder is used, one half being above and the other
below the line of the propellers; these rudders are worked by means of
a small auxiliary, engine, which is started, stopped, and reversed by
means of the electrical current. The current passing in one direction
starts the engine ahead, putting the helm to starboard. If the current
is broken, the engine stops and the rudder swings amidships. The
current passing in the opposite direction reverses the engine and puts
the helm to port.
In the firing circuit there are two resistance-coils, one in the boat
and one by the operator; the charge may be fired through either one of
the coils, but not through both. When the nose of the torpedo strikes
a resisting object the coil in the boat is cut out of circuit and the
charge is exploded. If the operator desires to fire before striking,
he can at any moment cut the coil near him out of the circuit and thus
fire.
The propelling engines have a throttle-valve which controls the
admission of gas from the reservoirs to the cylinders, the valve being
in connection with a balanced lever. The current passing one way draws
down one end of the lever, opening the valve, and passing the other
draws the other end down, closing it.
In one modification of this torpedo the forward compartment or magazine
is made detachable, so that on striking an object it breaks adrift
and sinks a short distance before exploding, thus gaining the best
depth of water. In launching these torpedoes from a vessel, a tube
is provided opening below the water-line and being provided with a
forward water-gate and a rear loading-door. The torpedo being put in
place, the rear door is closed, the gate raised, admitting the water,
and the torpedo launches itself after the engine is started. In order
to sink or raise the boat, a water-chamber is supplied having a valve
for admitting outside water and another for the admission of gas. By
sending a current one way, the water-valve is opened and water is
admitted until the torpedo is sunk to the required depth. By sending
the current the other way, the gas-valve is opened and the pressure of
the gas forces the water out and the torpedo rises.
The Lay torpedo may be used for clearing river obstructions, by laying
out small charges in any position or by dragging a grapnel. In the
latter case, an exploding charge is attached to the upper end of the
grapnel-chain. When the grapnel holds fast to any obstruction the
operator is notified, and by means of an electrical current he detaches
the charge, which slides down the grapnel-chain and explodes at the
obstruction, blowing it away.
TOWING TORPEDOES.
_The Harvey Torpedo._
[Illustration: Harvey Torpedo.]
[Illustration: Towing-Reel.]
[Illustration: Levers.]
[Illustration: Firing-Bolt.]
The general form of the Harvey torpedo is that of a box of a
rectangular vertical and trapezoidal horizontal section, intended to
float on end and tow at an angle from the ship’s keel. The case is
generally made of copper or Muntz’s metal sheathed with wood; the upper
inner edges being provided with shackles for attaching a towing-span.
The body of the torpedo is also the magazine, large enough to hold from
33 to 58 lbs. of gun-cotton. The firing-bolt with its fuse attachment
enters the magazine from the middle of the top or deck of the torpedo.
This bolt is acted upon by a series of levers so arranged that if
the torpedo strikes in any position, one of the levers will drive
the bolt down and explode the fuse. In the later patterns of Harvey
torpedoes there is also a small rudder attached, by which the course
of the torpedo is regulated when the tow-rope is suddenly slacked.
The sling is made with four legs going to the corners of the torpedo
and of a length to bring the centre of effort in the right position
for towing the torpedo at a good angle of divergence. The firing-bolt
is so arranged that the torpedo may be fired in three different ways:
electrically on contact, mechanically on contact, or electrically at
will. The mechanical arrangement is an ordinary chemical fuse placed
in the firing-bolt in connection with a small vial of sulphuric acid.
When the firing-bolt is forced down by the contact of the levers with
any resisting substance, the vial is broken by coming in contact with a
stout needle and the acid ignites the fuse. For firing electrically at
will, a platinum-wire fuse is used; one terminal going to earth at the
torpedo, and the other passing through the firing-bolt and attaching to
the insulated wire core of the tow-rope leading aboard ship. To fire on
contact electrically, a resistance-coil is introduced in the circuit
at the fuse in such a manner that by forcing the firing-bolt down the
resistance-coil is cut out of the circuit and the fuse is fired by the
short circuit.
The firing-bolt is fitted to act with a pressure of from 30 to 40 lbs.
on its head, and under ordinary circumstances is secured by a key in
the ordinary manner of keying bolts. If these torpedoes are left to
sink of themselves, they will explode at a depth of about 60 fathoms
from the pressure of the water on the head of the bolt.
In order to hold the torpedo steady when towing, it is provided with
cork buoys which tow astern of it. The buoy-rope is rove through a ring
at the after-end of the torpedo, and has an eye spliced in its end to
which the tow-rope knots after reeving through the eye of the sling.
The firing-bolt key has a small line attached to it by which it is
withdrawn whenever desired after the torpedo has been launched. The
tow-rope coming from the torpedo reeves through a leading-block on a
spar lashed about 25 feet above the deck, and, coming inboard through
another leader, passes to a reel secured on deck and controlled by
friction-brakes.
To launch this torpedo, it is hoisted by its tow-rope clear of the
side, and the rope then being rapidly veered until the torpedo strikes
the water and then gradually checked, it diverges at once. Veering
then slowly, the torpedo takes its position at an angle of about 45°
from the ship’s side. In attacking a vessel, when the torpedo has been
towed to within a short distance of the desired point, the tow-rope
is rapidly veered and the torpedo dives; checking the rope, it rises
almost immediately, and at a very sharp angle bringing up against the
vessel’s bilge. In case it becomes necessary to get rid of the torpedo,
the tow-rope is cut at the reel and unreeves and the torpedo sinks.
There are two rings for reeving the buoy-rope through, a large one and
a small one. If the rope is rove through the large ring, the torpedo
is lost when the tow-rope is cut; if rove through the small ring, the
knot connecting the buoy-rope and the tow-rope brings up against it,
and the torpedo is held up and buoyed the length of the buoy-rope below
water. In securing the torpedo after the key has been withdrawn from
the firing-bolt, a pair of tongs is used to grasp the bolt and keep it
from being forced down.
_The Menzing Towing Torpedo._
This is a modification of the Harvey, used in the German service,
intended to overcome objections to the original in regard to facility
of use. The general shape is slightly different, the forward end being
wedge-shaped so that the torpedo may be towed on either side. This
torpedo has two tow-ropes, each rove in a similar manner. The ends
of the ropes are provided with two legs which are made fast to the
after-end of the torpedo, where is a small rudder, the ropes coming
to it and acting on it in such a manner that when a strain is brought
on one it turns the rudder in the opposite direction. Secured to the
bow of the torpedo is a crane, having at its end an eye through which
the main part of both tow-ropes reeves. If it is desired to tow on
the starboard side, the starboard tow-rope is slackened, bringing the
entire strain on the port one; the crane at the bow of the torpedo
swings around by the strain until it brings up against a knot at the
splice of the legs, thus forming with the legs a complete bridle; the
divergence of the torpedo is at the same time assisted by the action
of the rudder. Levers for firing mechanically are applied in much the
same manner as in the Harvey. A circuit-wire for electrical firing and
buoys for steadying the torpedo are also used. By these arrangements
the torpedo may be towed astern until required for use, and then by
slacking the necessary tow-rope it may be swung out on either quarter
desired.
[Illustration: Menzing Torpedo.]
_The French Towing Torpedo._
This torpedo is in the shape of a long box tapered at the forward end.
It is made of wood, with a cork bow, the powder-chamber being hung
between the cork and the main body in such a manner that it may be
detached automatically. This is secured by a bolt projecting from the
top of the powder-case, whose head is held by a movable plate. The
slot in the plate through which the bolt-head passes is larger than
the bolt-head, so that when the plate is knocked back the bolt slips
through and the magazine is detached. Two curved whiskers project
forward from the plate as contact-points. In order that the torpedo may
be exploded at the proper depth, two shafts are pivoted to the bottom
of the float and attached to the magazine. When the latter is detached
it drops down the full length of the shafts (9 feet below the surface),
and on reaching that position the electrical circuit is closed and
the charge is fired automatically. To fire the torpedo at will, a
miniature gun is mounted on the after-part of the plate, which is fired
by electricity; the recoil draws the plate back and thus releases the
chamber. The magazine of this torpedo holds 33 lbs. of dynamite.
[Illustration: French Torpedo.]
SPAR-TORPEDOES.
_The American Torpedo._
[Illustration: American Spar-Torpedo.]
American spar-torpedoes are of two general forms. The first,
for gunpowder charges, is in the shape of a long cylinder with
hemispherical ends. The second, for dynamite charges, is in the shape
of a large double convex lens. The powder torpedoes have a capacity for
a charge of from 75 to 100 lbs. of small-grain powder; the dynamite
ones have a capacity of from 15 to 30 lbs. In the gunpowder torpedo a
large hollow spindle passes through the axis, closed and secured at
one end by a large nut. This spindle is pierced with flame-holes at
short distances, so as to permit the flame from the fuse to penetrate
and ignite all parts of the powder-charge at once. Around this spindle
is a guard of wire gauze to prevent the powder from the charge sifting
into and choking the flame-passages. This spindle projects some little
distance beyond the inner end of the torpedo-case, forming a handle
or support by which the case is attached to a spar. At the inner end
on each side of the spindle is a loading-hole secured by nuts and
washers. There are also four handles, two on each side of the case,
for convenience in transporting. The 100-pdr. torpedo loaded and fused
weighs about 360 lbs. The torpedo-fuse, which is an electric one,
finds a place by itself inside the spindle, the terminal wires passing
through a simple water-tight gland.
[Illustration: Socket for American Spar-Torpedo.]
[Illustration: Wood and Lay’s Spar-Torpedo.]
[Illustration: Boat-Fittings for American Spar-Torpedo.]
On the end of the torpedo-spar is lashed a cast-iron sleeve into which
the end of the spindle is keyed. The torpedo-spar for use on the bows
or broadsides of vessels varies in length from 20 to 50 feet, and is
supported and pointed by guys and lifts in the same manner as is common
with swinging spars generally. The wires from the fuse are brought in
along the spar to the electrical machine and firing-keys arranged in
suitable positions.
The spars used in boats are generally arranged on a different principle
from those attached to the bows or beams of high-sided vessels.
Arranged to work in a swivelled sleeve with a martingale at the rear
end to regulate the depth to which they shall sink, the spar is either
launched or dropped over and is permitted to swing without guys, the
operator watching and exploding it as it is brought abeam and into the
desired position by the driving ahead of the boat.
[Illustration: Fitting for Heel of Spar Ship-Torpedo.]
[Illustration: Chafing-Plate for Heel of Spar-Torpedo.]
The spar used with the dynamite torpedo is an iron or steel bar of
diminished cross-section in order to offer a minimum resistance to the
water, with a hinged piece at its rear end bolting to the keelson of
the boat and acting as a martingale.
TORPEDO VESSELS.
In several of the navies of the world gun-boats have been designed for
the purpose of using torpedoes, either locomotive or spar, to the total
exclusion of battery—or, in some cases, with a limited artillery—fire.
_Pietro Micca_ (Italian).
This vessel, having a displacement of about 530 tons, is built very low
in the water, with a curved deck or cover, and is not armored except as
regards a deck under the curved cover and over the engines, intended
to resist the penetration of plunging projectiles, and which is of
laminated steel 2¼ inches thick. Her estimated speed is 18 knots, and
she is provided with tubes for discharging Whitehead torpedoes ahead,
abeam, and astern.
_Rau_ (Swedish).
_Ziethen_ (German).
_Vesuvius_ (English).
_Uzreef_ (Russian).
Whitehead torpedo gun-boats of from 400 to 700 tons displacement and an
estimated speed of from 13 to 16 knots. The peculiarity of the Vesuvius
is in having an elbowed smoke-stack carried along the deck. The Rau
carries a light rifled gun. All carry machine-guns.
_The Alarm_ (American).
The Alarm is an iron ram gun-boat, built on the transverse bracket
system, with a double bottom and water-tight bulkheads every 25
feet. Her dimensions are: length, 173 feet; beam, 28 feet; draft, 11
feet—which may be increased by sinking the vessel to the level of the
upper-deck beams, arrangements having been made for the admission and
ejection of water in the compartments formed by the double hull. The
torpedo system of this vessel consists of three hollow steel tubes,
one projected from the end of the ram a distance of 30 feet, and one
from each broadside, 17 feet. These tubes slide in and out on frames,
and are worked by small auxiliary engines and winches; the torpedo
is fitted to the end of the spar and is fired by electricity. The
port from which the spar is projected, being below the water-line, is
provided with a water-box and double doors and heavy rubber washers,
which grip the spar water-tight as it is run out.
In addition to the torpedo system, this vessel is arranged to carry
a 10-inch rifle forward. Her ram is strengthened, and her bow is
protected for some distance by a plating of 4½ inches. On her rail
she carries machine-guns to resist the attack of torpedo-boats.
Her propeller is of a novel pattern, serving as steering-gear and
propelling power. This vessel was originally fitted with a propelling
apparatus known as the Fowler steering-wheel, a novel propeller which
both gave the vessel headway and steered her. The blades of the
propeller were worked by means of a simple steam-valve arrangement
manipulated by the helmsman. The steering qualities with this apparatus
were little short of marvellous, as she could be driven and steered
with as great facility astern as ahead, and could even be worked
sideways. Her speed, however, was deficient, never reaching ten knots.
At present the vessel has been fitted with the Mallory steering
propeller, a form of screw with a jointed shaft so that it may be
revolved about a vertical axis. This screw promises to give a speed
more nearly warranted by the fine lines of the vessel.
_The Intrepid_ (American).
This vessel is a gun-boat of about the dimensions of the Alarm, having
a short, heavy ram bow and an armored belt at the water-line of five
inches thickness all around. Her load draft brings her upper deck to
within three feet of the water-line. This vessel carries no armament
except a few Gatling guns on the rail, and her torpedo system consists
of four ordinary swinging-spar torpedoes, two on each beam. Ordinarily
these spars lie in crutches alongside, and they are manipulated by
topping-lifts and guys in the ordinary way. The torpedoes are exploded
by electricity.
_The Destroyer_ (American).
[Illustration: Ericsson’s Torpedo Vessel (Destroyer).]
This vessel is 130 feet long by 12 feet beam and 10 feet draft, built
with a straight bow, bow and stern lines being the same and very sharp.
She has no upper-deck rail, this deck being very low, with a long
superstructure rising amidships. There are no openings in the sides of
this superstructure, so that if desirable the vessel may be run with
her upper deck completely under water. Thirty-two feet from the bow
a heavy armored bulkhead crosses the vessel, inclined at a vertical
angle of 45°, and intended as a thorough protection to the engines and
boilers, enabling the vessel to approach bows on with impunity. Her
armament consists of a bow-torpedo, which is projected from a tube in a
manner not unlike the firing of a projectile from a gun. This torpedo
consists of a solid block of light wood having inserted in its forward
end a heavy bursting-charge in a steel case. The transverse section of
this torpedo is square; longitudinally it is a rectangle with sharpened
ends. Ignition of the charge is obtained by means of a percussion fuse.
To project this torpedo, it is inserted in a tube provided with
water-gates, fixed in the bow of the boat just above the keel. A steam
piston-rod fits against the after-end and pushes the torpedo out with
a velocity sufficient to send it at least 100 feet. The weight of the
torpedo is about 1400 lbs. This vessel has been tried, but the system
is not yet perfected.
_The Uhlan_ (German).
This vessel is of a novel type, consisting of two separate hulls, one
within and abaft the other, the intervening space being filled with
cork. She carries affixed to a ram which projects ten feet forward
from the stem a dynamite contact torpedo. Arranged to travel at a high
speed, the idea is to carry her at full speed against the enemy, the
crew finding refuge on a small raft which she carries and which is
detached just before her striking. It is not expected that the main
hull, in which are the engines and steering-gear, will be injured by
the explosion. The raft, it is understood, is not completely detached
from the vessel, but a long tow-line is paid out rapidly, and after
the explosion of the torpedo the crew haul alongside and take the boat
clear ready for another attack.
TORPEDO-BOATS.
_The Thornycroft Torpedo-Launch._
This boat is built to combine great speed with a moderate seaworthiness
and resisting power. The dimensions range as follows: length, 57 to 85
feet; beam, 7½ to 10 feet; draft, 3 to 4 feet. They are built of steel
of an average thickness of ³/₁₆ an inch, being completely decked over.
Generally they are divided into six separate water-tight compartments.
The forward and after ones are store-rooms; the second one is arranged
for the accommodation of the crew; the third is the pilot-house;
fourth, engine and fire room; and fifth, for the accommodation of
officers. The single-screw shaft projects some distance beyond the
stern-post to allow the double rudder to work forward of it. The screw
itself is of a peculiar construction, so built as to project the water
straight aft instead of radially. These launches are fitted for either
spar or Whitehead torpedoes. In the former case the swivelled sleeve in
which the spar works pivots abreast the pilot-house. In the latter case
two methods are in use. By one, a Whitehead is carried on deck on each
side mounted on a carriage running on rails, by which they may be run
up to a firing-case on the forward part of the deck. This firing-case
is mounted on a pivot-carriage and has depressing-gear, so that the
torpedo may be pointed in any desired direction. A pointing apparatus
is provided in the pilot-house by means of which allowance of angle may
be made for the movements of the boat or of the attacked vessel. The
pivot-circle is graduated so that the torpedo may be correctly aimed
with but little difficulty. By the other arrangement, a Whitehead is
carried on each side on pivoted davits in a sling, so that it may be
lowered into the water; the machinery is then started by hand, and the
torpedo moves off without being projected. In this case the torpedo can
only be fired right ahead.
[Illustration: H. M. Steam Torpedo Launch "Lightning".
Thornycroft Torpedo-Launch.
Length (extreme) 84 6
Beam 10 10
Draught 5 0
Speed 18 Knots]
_The Yarrow Torpedo-Boat_
[Illustration: Yarrow Torpedo-Launch.]
This is a launch of the same general construction as the Thornycroft,
although a higher rate of speed is attained by this type, and there
are several important modifications. The fire-room, or stoke-hole, is
completely separated or bulkheaded off from the boiler, except the
front part, so that in case the boiler collapses or is pierced by a
shot there is no danger of scalding the crew. The pilot-house is placed
aft in the compartment occupied by the officers. There is no visible
smoke-stack. Two ports are cut in the sides of the launch, one on each
side, and the products of combustion may be carried through either or
both. The ports are provided with valves, which are held open by the
force of the blast, but which close immediately if struck by a wave.
The helmsman can direct the smoke through either port, so that in
approaching a vessel the one on the side next to her is closed and the
smoke through the other port is partially masked by the side of the
boat. When running in a seaway both these ports may be closed, and a
temporary smoke-pipe is shipped in the usual place.
These boats are provided with a rudder at each end, both rudders being
operated by the wheel at the same time. The forward rudder may be
drawn up into a well, if desired, or in case that it gets fouled it
can easily be dropped overboard. These boats have attained in smooth
water a speed of 22 knots an hour. The torpedo arrangements are similar
to those of the Thornycroft. Above 18 knots there is no noticeable
vibration of the frame.
_The Herreshoff Torpedo-Boat._
[Illustration: Herreshoff Torpedo-Launch.]
The general type of hull is the same as that of the Yarrow and
Thornycroft, except that it is of composite construction, having
a steel frame with wood planking below water and steel above. The
propeller is a single two-bladed screw, placed under the keel just
abaft the middle of the boat, the hollow steel screw-shaft being put
in on a curve. The rudder is of the balanced type, and is suspended
underneath the after-part of the keel. The pilot-house is abaft the
smoke-pipe. The boiler of this boat is of a novel character. It
consists of a cylindrical combustion chamber about 4 feet in diameter,
within which is a spiral coil of about 300 feet of two-inch pipe.
This coil is continued at the top so as to form a kind of dome under
the cover of the combustion chamber. By the side of the boiler is a
separator into which the steam passes before it goes to the engine. The
water from the feed-pump is admitted at the top of the coil, and during
its course to the bottom the greater part of it becomes converted into
steam. Having passed through the entire length of the coil, the steam
and water are discharged together into the separator, in such a manner
that the water is entirely separated from the steam and can be blown
off as required. The steam is taken from the top of the separator and
returns through a short coil placed inside the combustion chamber,
where it becomes superheated and is led thence to the engines. By means
of this boiler a good working pressure can be obtained in about five
minutes from the time of lighting the fires. This boat may be rigged to
carry either the Whitehead or the spar torpedoes. Its speed is about 18
knots, equal to that of the Thornycroft.
[Illustration: Herreshoff Boiler.]
SHIPS’ BOATS.
Steam-launches are at present, as a rule, fitted with spar or Whitehead
torpedo-gear of a general and simple type. It is not intended that
these boats should be classed as fighting torpedo-boats, as they
lack the requisite speed and protection, and, as a rule, are too
noisy to be of use except in a general or concentrated attack. Such
boats find their greatest sphere of usefulness in clearing channels
of obstructions and countermining. For the former work many are now
provided with electrical valve-gear and steering apparatus, by which
they may be controlled from a boat towed some distance astern, as in
the manipulation of the Lay torpedo.
SUBMARINE BOATS.
At different times during the development of torpedo warfare there
have been many attempts to construct and perfect submarine boats
of different types, but in no case has an attempt to use one been
successful. The United States corvette Housatonic was sunk off
Charleston Harbor in 1864 by a submarine torpedo-boat, but there are
excellent reasons for believing that she was at the time of the attack
used as an ordinary surface-boat with a bow-torpedo on a spar. In
most cases the boats used, or rather designed, have been propelled by
hand-power, their rate of speed being very low. Attempts are being made
in all countries to perfect some form of submarine boat, and, judging
from the experimental success attained heretofore, it is fair to
suppose that some type will finally prove successful, although in any
case its use would be extremely limited.
DRIFTING TORPEDOES.
Torpedoes of this description have been used in great numbers in time
of war, but only with indifferent success. The especial function of
the drifting torpedo is the destruction of vessels lying at anchor,
the torpedo being sent adrift at a convenient point and allowed to
float either at the surface or by means of a buoy at some distance
below, and by the action of the current to be carried into contact with
the vessel, being exploded by a contact-fuse. There is no especial
shape considered superior for this type, and generally the torpedoes
are extemporized from the most convenient materials at hand. Of the
many types that have been tried there are two which may be considered
especially dangerous.
The first of these is a torpedo intended to be dropped by a vessel
being chased, to be caught by the one in her wake. This type may be
described in general as two torpedoes of a size sufficient to contain
20 or 30 lbs. of dynamite, connected by a rope or light chain bridle,
and floated by flat water-colored buoys. Dropped from the stern of
a vessel, the bridle is caught by the bow of the chaser, and the
torpedoes being swept alongside explode against the bilges.
_Lewis’s Drifting Torpedo._
[Illustration: Lewis’s Beam Torpedo.]
This torpedo, intended to reach a vessel at anchor and surrounded by
a boom of logs, consists of a case of powder or dynamite resting
loosely on a small shelf attached to one extremity of a heavy pine
beam, ballasting it in such a manner that it will float on end with the
top just above water. The torpedo is attached to the beam by a loose
chain bridle, the ends of which are stapled respectively to the lower
end and just above the centre of gravity of the beam. The shelf itself
is hinged, and is held in position by a catch operated by a small
bell-crank lever on top of the beam. This beam on coming in contact
with a boom is canted slightly, and the lever being tripped the shelf
drops from under the torpedo, which, hanging by its bridle, cants the
beam almost horizontally, thus allowing it to slip under the boom and
float on against the ship’s side, where the torpedo explodes on coming
in contact.
DEFENCES AGAINST OFFENSIVE TORPEDOES.
Vessels at anchor in protecting themselves against torpedoes
establish three separate lines of defence. The outer line consists
of guard-boats; the boats of the ship, either carrying machine and
boat guns or having their crews armed with rifles, patrolling the
approaches to the ship at such a radius as may be well guarded by the
number of boats employed. The second line consists of a boom of logs or
spars arranged around the ship at a distance of from twenty to fifty
feet, having in addition, wherever practicable, heavy nets which hang
down below the level of the keel. The third and inner line consists
of the machine-guns and small-arms of the crew, the double hull and
compartment construction of the vessel itself, and powerful electric
lights which at intervals sweep the water in the vicinity of the
vessel, lighting up every approaching object.
DEFENSIVE TORPEDOES.
Torpedoes of this class may be described generally as being either
heavy cases of explosive material resting on the bottom of shallow
channels and fairways, and usually exploded at will by electrical
fuses, or smaller torpedoes anchored and either buoyed or supported
at from three to twelve feet below the surface. The first class of
torpedoes is of crude and varied construction, being simply heavy cases
of boiler-iron of a capacity for from 100 to 200 lbs. of dynamite or
1000 to 2000 lbs. of powder, caulked water-tight and sunk generally
within easy range of a heavy battery, in a position where a vessel
would probably stop or anchor to open fire, or else in a shallow
channel where a ship must pass directly over it.
The buoyant torpedoes are of different form; the most successful types
being
_The Frame-Torpedo._
This consists of a row of heavy beams planted across a channel similar
to a “chevaux de frise.” The inner ends of the beams are securely
anchored to the bottom, the latter giving them a support when they are
ran into. The outer ends carry each a single torpedo shaped like a
large rifled shell and holding from 60 to 100 lbs. of powder; bolted to
it so that the tops of the torpedoes are about eight or ten feet below
water. These ends are moored so as not to swing about too much in the
current. Just under the outer ends a frame is constructed to support
the beams in case they get waterlogged. Contact-fuses are used with
these torpedoes, and the whole arrangement serves the double purpose of
acting as a torpedo and as a construction defence. These beams are also
used singly in many cases.
[Illustration: Frame-Torpedoes.]
_Brooks’s Torpedo._
This form of torpedo is intended to baffle attempts at removal by
sweeping with drags and grapnels. The beam used in this case is of a
length sufficient to allow the top of the torpedo to be at the proper
distance below water when it is vertical. The heel of the spar is shod
with a pointed iron casing having a ring in the end connected to an
anchor-shackle, the anchor being completely buried. In this manner
the beam is free to oscillate. The torpedo, which is conical with a
dome cover, ships on the upper end of the beam, all sharp corners and
edges where a rope or grapnel might catch being avoided. In the top
of the torpedo are placed five contact-fuses. In order to make this
torpedo still more difficult of removal, it is placed in connection
with a heavy ground-torpedo called a turtle-back in such a manner that
any attempt to remove it from its berth causes the explosion of the
turtle-back.
_Singer’s Torpedo._
This torpedo contains an air-chamber in the upper part, whilst all the
lower portion is devoted to the charge, varying in weight from 50 to
100 lbs. of powder. On top of the case is a heavy conical iron cover
loosely secured, so that if the torpedo is struck a violent blow or is
canted well over it will fall off. This cover is secured by a wire to a
mechanical fuse (there are several different types) in such a way that
the jerk given to the wire when the cover falls off will explode it.
[Illustration: Brooks’s Torpedo.]
[Illustration: Singer’s Torpedo.]
[Illustration: Barrel Torpedo.]
_Barrel Torpedoes._
Barrels are frequently used as torpedoes, being thoroughly caulked and
pitched and strengthened as much as possible. They are slung with rope
or chain slings, moored in position, and exploded either by contact or
electrical fuses. In the majority of cases with defensive torpedoes at
present, they are so arranged as to be fired either by contact or at
will.
TORPEDO-FUSES.
Torpedo-fuses may be classified under four different heads; viz.,
Percussion, Friction, Chemical, and Electric.
A percussion fuse is one in which the flame is produced by a blow on
some fulminating compound. Of such a type is the fuse of the Whitehead
torpedo, which in principle is precisely that of the firing arrangement
of breech-loading small-arms. The shock on the nose of the torpedo
starts it back, releasing the firing-pin spring, which driving against
a cap or fuse of fulminate, explodes it. The fuse of Singer’s torpedo
cannot depend directly on the shock of collision to explode it, as the
shock might be very light. As an intermediary, therefore, the heavy
cover of the torpedo is used, which falls off when the torpedo is
tilted, and by its descending weight releases the lock mechanism. This
consists of a firing-pin and spring secured vertically underneath the
torpedo and held retracted by a small pin. This pin is withdrawn by the
falling cover, permitting the firing-pin to drive forward against the
bottom of the torpedo. Just over the spot where it strikes is a short
rod travelling in guides, the upper end being in contact with a small
capsule of fulminate, which is exploded by the shock of the outside pin.
_The Torpedo Time-Fuse_
is in principle a lock mechanism in which the firing-pin catch is in
connection with a train of clockwork. This clockwork being set to
run for a certain length of time, the torpedo is set adrift to float
against the vessel or obstruction, and the torpedo explodes at the end
of the time for which it is set. The original and most crude form of
this type of fuse is a candle cut to a certain length, the bottom being
connected to a quick-match. It is not in this case a percussion fuse,
as the quick-match communicates directly with the charge.
[Illustration: Clockwork Fuse.]
_McEvoy’s Fuse_
consists of a percussion system in connection with a small propeller.
As long as the torpedo drifts with the current the propeller does not
revolve, but if it is brought up in any way the force of the current
starts the propellers, which after a few turns release the firing-pin
spring.
The torpedo by means of which the Albemarle was sunk (see cut, page
335) was exploded by a percussion fuse of still a different nature.
The torpedo itself was attached to the end of a spar, but just before
explosion it was intended to detach and capsize. A hollow tube passed
through the axis of the torpedo, having at the nose-end an ordinary
percussion-cap arrangement. The rear half of the torpedo formed an
air-chamber, and at the rear end of the tube an iron ball, free to move
along the tube, was held in place by a small pin to which a laniard was
attached to be pulled by hand. The torpedo being thrust by the spar
under a vessel was detached, and the air-chamber caused it to tumble
bottom up immediately. The pin then being withdrawn by the laniard, the
ball dropped on the percussion-cap and fired it.
[Illustration: McEvoy’s Propeller-Fuse.]
[Illustration: English Dynamo-Electric Fuse.]
_Hill’s Fuse_
consists of a brass body having a percussion anvil screwed into its
lower end. A spiral spring surrounds this anvil, projecting slightly
above it and forming a seat for a light case holding the fulminate,
which is of a very sensitive composition. Covering the top of the
fuse-case, and just clear of the fulminate-case, is a light copper
dome. A slight blow on this dome presses it in and drives the fulminate
down on the anvil.
_McEvoy’s Improved Percussion Fuse_
consists of a fuse-case containing an ordinary spring gun-lock, nipple,
and percussion-cap. The hammer of the lock is held back by a vertical
rod free to travel in a guide. On top of the rod is a ball held in
place lightly by the upward pressure of a spring. In case that the
torpedo is struck and tilted over the ball falls from its seat on the
rod, the latter is forced up by the spring, releasing the hammer and
exploding the percussion-cap.
_Friction-Fuses._
Friction-fuses as a rule consist of some arrangement by which an
ordinary friction cannon-primer is exploded. This is done by attaching
a firing laniard to the friction-bar of the primer and either leaving
it free, so as to fire at the will of the operator, or attaching it
in such a way that the momentum of a vessel catching it will pull it.
McEvoy’s improvement on Singer’s percussion fuse consists in attaching
the laniard of a friction primer to the heavy cover.
[Illustration: Barrel Torpedoes with Friction-Fuses.]
_Chemical Fuses_
[Illustration: Chemical Fuse.]
are those in which substances separated until required for action are
then brought into contact and unite chemically with an explosive effect.
_Sulphuric-acid Fuse._
This fuse consists of a brass fuse-case containing the magazine and
crowned by a thin lead cylinder containing the chemicals, which consist
of a small closely sealed glass phial of sulphuric acid placed in the
tube and packed with a mixture of potassium chlorate and loaf-sugar. A
slight blow on the lead cylinder breaks the bottle, thus permitting a
contact between the explosive mixtures.
_Harvey’s Torpedo-Fuse._
The principle of this fuse is precisely similar. The bottom of the
firing-rod is in this case hollowed and partially packed with the
potassic chlorate and loaf-sugar mixture. Over it a small bulb
containing a few drops of sulphuric acid is placed and packed carefully
with raw cotton. The mouth of the hole is then sealed with a lead
capsule. The firing-rod is itself suspended over a firing-pin against
which it is driven by the levers on the top of the torpedo.
_Electrical Fuses_
depend upon the heating powers of an electrical current to ignite
certain explosive substances, preferably gun-cotton. Although there
are many modifications of the electrical fuse, they almost without
exception agree entirely in general make. Two current wires are
necessary, called terminals, and having their inner ends separated, in
order that some substance offering a high resistance to the passage
of the current may be inserted between them. The terminals are of
copper wire; the resistance material or bridge is generally of fine
platinum wire, although other substances are used in different types.
The terminals are as a rule separated by a small block of hard wood
which forms an insulator and a support. Around the bridge a wisp of
gun-cotton is generally wrapped, although here again other explosives
are used in modified forms. This combination is called an exploder,
and it is inserted in a fuse-case or magazine containing powder or
gun-cotton. The exploder and magazine together form the fuse. One of
the terminals is generally attached to the exterior of the torpedo,
which forms an earth; the other one is connected with an insulated wire
or cable leading to the electrical battery. These fuses are made to
explode either at will or on contact. If they are to explode at will,
the firing circuit as a rule is not completed until the moment desired
for explosion. If they are to explode by contact, the general manner
of use is to insert in the circuit at some part a resistance-coil
of sufficient force to weaken the current below the firing point.
At the moment of contact, the resistance coil is automatically cut
out and the torpedo is fired. Another way is to use what is called a
circuit-closer, which normally leaves the circuit broken, but on being
touched the circuit is closed and the torpedo is fired.
[Illustration: American Dynamo-Electric Fuse.]
[Illustration: English Dynamo-Electric Fuse.]
One advantage of the electrical fuse is the facility with which the
whole circuit may be examined at any time to test its condition. It is
simply necessary to send a very weak current through the circuit, and,
the resistance being known, the length of the circuit can be measured
electrically and the position of flaws may at any time be located. The
modifications of the different fuses depend in a great manner upon the
type of generator of the current, as voltaic batteries, dynamo- and
magneto-electric machines are used according to the position of the
torpedo.
CLEARING CHANNELS OF TORPEDOES.
The greatest skill and care is necessary in attempting to clear
a channel of mines and torpedoes. Light-draught boats, launches,
gun-boats, drag-nets, grapnels, and materials for handling torpedoes
at a distance of thirty or forty feet are indispensable. Torpedoes of
the Brooks class may be dragged over many times and escape notice. The
frame-torpedo requires the aid of counter-mines or large torpedoes
extemporized and sunk on them to blow them to pieces. The shallow water
both sides of the channel must be carefully and thoroughly dragged for
leading wires. Boats on search must proceed with frames rigged from
their bows to catch and explode torpedoes in advance. Deep-draught
frames of timber must be dragged up or floated down a channel. Muddy
bottoms must be thoroughly sounded, and after the search is complete
deep-draught vessels cannot pass through suspected channels without
torpedo-catchers rigged from their bows. Too close an examination of a
torpedo after it is picked up must be avoided. It may almost invariably
be easily and safely exploded, and no better disposition can be made of
it.
EXAMPLES OF THE USE OF TORPEDOES DURING THE PAST TWENTY YEARS.
_Whitehead._
Sent from the British frigate Shah against the Peruvian iron-clad
Huascar, May 29th, 1877. During the running fight between these
vessels, the Shah discharged a Whitehead from a bow tube under water,
which failed to reach the Huascar, the reason given being that at the
moment of firing the latter changed her course. It is to be presumed
that the torpedo in this case was carefully aimed, as there was no
cause for great hurry. The Huascar could not be aware of the moment of
firing, and the failure appears to demonstrate the great difficulty of
using this type of torpedo between rapidly moving vessels at distances
of eight hundred yards or over.
Sent from Russian steam-launches against Turkish iron-clads off Batoum,
December 28th, 1877. The Turkish vessels in this instance were lying
at anchor, surrounded by booms of logs and vertical timbers, and
having guard-boats out. The Russian launches succeeded in passing the
guard-boats and approaching to within less than a hundred yards of the
Turks before they were discovered. Two Whiteheads were then launched at
one iron-clad, missing their mark completely, both being found on the
beach, unexploded, next morning. The attributed causes of the failure
were non-familiarity with the complications of the torpedo itself,
darkness, and a slight swell.
Sent from Russian torpedo-launches against a Turkish revenue vessel,
January 26th, 1878. In this instance the torpedo-launches were entering
Batoum harbor with the intention of attacking the iron-clad fleet,
when they were met by a revenue steamer coming out. Whiteheads were
discharged at a distance of less than one hundred yards, and the
steamer was struck and sunk.
The Lay torpedo has never been used in war.
Towing-torpedoes were used on several occasions by the Russians against
the Turks, but never successfully.
_Spar-Torpedoes._
Attack by a steam-launch armed with a spar-torpedo on the Confederate
iron-clad Albemarle, October 27th, 1864. The Albemarle in this instance
was secured to a wharf and surrounded by a boom of logs at a distance
of about thirty feet. The Federal steam-launch approached within one
hundred yards of the boom without being discovered. Fire then being
opened on her, she started ahead full speed, _passed_ the ram, and made
a complete turn in order to get speed and direction for striking the
boom a fair blow. Hitting the boom, the launch breasted it in several
feet and mounted it, evidently coming to a stand-still. At this moment,
and whilst under a close fire, the torpedo-spar was pushed under the
ram and the torpedo was exploded fairly, thus sinking her. In this
case success was due entirely to a cool and deliberate execution of a
thoroughly developed plan.
Attack by Russian launches armed with spar-torpedoes on the Turkish
monitor Duba Saife, on the Danube, May 26th, 1877. In this attack the
launches passed the guard-boats without being seen. The monitor was
not protected by booms, and two launches, making a dash at her from
opposite sides, planted their torpedoes fairly, exploded them, sank the
monitor and escaped.
Attack by Russian spar-torpedo boats on the Turkish fleet at Sulina,
June 10th, 1877. There were six torpedo-boats arranged in two divisions
in this attack, the two fastest boats leading. These leaders reached to
within thirty yards of the Turks before being discovered.
Fire was then opened on them. The first boat, coming down on the bow of
one of the monitors, fouled her cable and swung alongside; her torpedo
was exploded, but not being put in proper position no damage was done.
The boat succeeded in getting clear, but was sunk by the Turks and the
crew captured. The other boat succeeded in exploding her torpedo, but
also failed to get it in position. The other division of boats did not
follow up the attack.
Attack on a Turkish monitor off Rustchuk by a Russian Thornycroft
boat. In this attack the Russians approached very closely before being
discovered. Fire was opened on the boat and the circuit-wires of the
torpedo were cut, rendering it harmless; the boat escaped.
Attack on Turkish monitors at Soukum Kaleh, August 24th, 1877. Four
torpedo-boats, taking advantage of an eclipse of the moon, dashed into
the Turkish fleet. They were discovered at a distance and a heavy fire
was opened on them, driving them off. One boat exploded her torpedo,
but it was not properly placed and did no harm.
Attack by a spar-torpedo boat on the United States frigate Minnesota,
April 9th, 1864. In this attack the Minnesota was unprotected; the
torpedo-boat was discovered about fifty yards away and fire was opened
on her. Her torpedo was properly planted and exploded, damaging the
frigate considerably, but the charge was not heavy enough to sink her.
Attack by a spar-torpedo boat on the United States corvette Housatonic,
February 17th, 1864. The boat used in this attack was in reality a
submarine boat, but there are good reasons for believing that on this
occasion she was used as a spar-torpedo boat. She was discovered about
fifty yards away, but there was no time to open fire on her. She
planted her torpedo fairly and exploded it, sinking the vessel and
herself at the same time.
Besides these attacks there were several during the American civil war,
in which the boats were discovered at a distance and driven off.