[Illustration: Plate 1.

‘Royal Sovereign’ ‘Camel’

TRIAL OF HARVEY’S SEA TORPEDO.

Kell Bros. Lith. London.]




                              INSTRUCTIONS
                                 FOR THE
                               MANAGEMENT
                                   OF
                          HARVEY’S SEA TORPEDO.

                                 LONDON:
                   E. & F. N. SPON, 48, CHARING CROSS.
         PORTSMOUTH: J. GRIFFIN & CO. DEVONPORT: J. R. H. SPRY.
                                  1871.

     LONDON: PRINTED BY WILLIAM CLOWES AND SONS, STAMFORD STREET AND
                             CHARING CROSS.




INSTRUCTIONS FOR THE MANAGEMENT OF HARVEY’S SEA TORPEDO.


To impart a thorough knowledge of the management of such an arm as the
sea torpedo is a matter of easy accomplishment by personal explanation;
especially so, when the arm is in the water, and practised with under
conditions that would obtain in its application to the disabling of, or
to the destruction of vessels against which it may be employed.

But in the absence of such mode of instruction, the following directions
are offered, with a hope that they will prove sufficiently explanatory of
an arm, which, like other arms, requires skill and aptitude in using it
effectively.

By the instructions here given, it must be understood, there are two
torpedoes; though both are of the same kind, they differ in construction,
by reason of the difference in the position of their respective planes,
so that one may diverge to port, and the other to starboard; the
direction of the divergence is known by the position of the slings and
rudder. There is a like difference in the exploding bolts; the bolts
which respectively belong to the port and starboard torpedoes are known
by the direction of their safety keys.

[Illustration: (A)

STARBOARD TORPEDO.]

[Illustration: (B)

PORT TORPEDO.]

The sea torpedo has the advantage of exploding only when in hugging
contact with the vessel attacked; the levers by which it is exploded are
so placed in relation to the tow-rope, that either the side or top lever
is found invariably to act effectively in forcing down the exploding
bolt at the instant of contact; this has been ascertained by the result
of many experimental trials.

The shape is an irregular figure, which can be best understood by
reference to the drawings (p. 4). The dimensions of exterior case are as
follows:—

                             ft.  in.

                  ⎧ Length    5   0
    Large Torpedo ⎨ Breadth   0   6⅛
                  ⎩ Depth     1   8¾

                  ⎧ Length    3   8
    Small Torpedo ⎨ Breadth   0   5
                  ⎩ Depth     1   6

[Illustration: (C)

SECTION (C).]

The exterior case is made of well-seasoned elm 1½ in. thick, iron bound,
and screwed together with water-tight packing between the joints, also
cemented with pitch. The interior case is made of stout sheet copper;
the case has two loading holes corresponding in size to two holes in the
deck, or top of the exterior case. These holes are made sufficiently
large to load with gun-cotton discs, if preferred. The loading holes
are fitted with corks, which are inserted before screwing on the brass
cap, to prevent any chance of accident through friction in screwing on
the cap; the bushing has the thread of the screw on the outside for
the same reason. If thought necessary, the cork can be cemented over
before screwing on the cap, which will render the joint doubly secure
from leakage. The centre of the copper case has a stout copper tube,
which is soldered to the top and bottom surfaces of the copper case, the
charge being all round it; into this centre tube is screwed the priming
case. It should be understood that both the exterior and inner cases are
thoroughly water-tight, so that in the event of the outer case being
damaged, still the charge in the interior case is preserved perfectly
dry, the cases being altogether independent of each other.

The capacity of the copper case of the large torpedo is such that it will
contain 77 lbs. of water; the capacity of the small one, 28 lbs.; from
these can be determined the quantity of any explosive agent with which it
may be desired to charge either torpedo.

The charges of various powders the torpedoes will contain are as follows:—

                                Large Torpedo.  Small Torpedo.
                                     lbs.            lbs.
    Glyoxilin                         47              16
    Schultze’s blasting powder        60              22
    Compressed gun-cotton             60              22
    Picric powders                    73              26
    Rifle grained powder              76              27
    Horsley’s original                80              28
    Horsley’s blasting powder         85              30
    Nobel’s dynamite                 100              35

The above must be considered an approximation, since much will depend
upon the labour expended in packing the torpedo.

Some of the powders named have not yet been manufactured on a large scale.

The priming case is made of stout sheet copper, and contains a large
bursting charge, which may be either rifle grained powder or a stronger
explosive, which is recommended.

[Illustration: (D)

SECTION.]

[Illustration: (E)]

In the centre of the priming case is a brass tube in which the exploding
bolt works, and at the bottom of this tube is a steel-pointed pin, which
pierces the capsule on the muzzle of the exploding bolt, when the bolt is
forced down. At the side of the brass tube, and near the base of the pin,
is a small hole, covered with thin brass foil, which will allow of an
escape of water into the priming case, should any have collected at the
bottom of the tube. The loading hole of the priming case is at the bottom
of the case, and arranged with cork and cap upon the same principle as
the loading holes for main charge. A powerful spanner is provided for
screwing in the priming case and caps of main loading holes, which are
fitted with leather washers to form a water-tight joint. The priming case
can be stored separate from the torpedo if preferred, but there is no
necessity for so doing unless it is charged with a dangerous compound.
When the torpedoes are being stored, a wooden plug is inserted into the
brass tube of the priming case; there is a cavity in the plug at the
lower end; the cavity is filled with a greasy composition, into which
runs the pin of the priming case when the ping is in its place; the pin
is thus protected from corrosion, and the tube of the case secured from
any foreign matter getting accidentally into it.

The exploding bolt is fitted to work with a pressure of about 50 lbs. on
the head of the bolt for the large torpedo, and 20 lbs. for the small.

[Illustration: (F)]

On account of the great proportional length of the stuffing box, it is
quite impossible for water to enter into the tube, and the pressure can
be regulated to the greatest nicety by the quantity of thread wound on.
The bolts are easily kept in order by turning them round occasionally in
their tubes, stored as they would be in the bolt magazine (see p. 20,
Fig. Y). The best lubrication for them is hog’s lard free from salt,
beeswax, neat’s-foot oil, in proportion 3, 1, 1. The bolt has several
grooves for the thread stuffing to be wound on, and in the event of its
working too easy, a few turns of whity-brown thread on the two lower
stuffings will suffice; should it work too stiff, revolve it in the
magazine tube until it works with the desired amount of pressure, which,
after a little practice, is well known by the hand. In the event of a few
drops of water entering the tube, which has never occurred, a provision
is made for its escape (see priming case), that it may not impede the
descent of the bolt. The cavity in the bolt for containing the exploding
composition is, in length and diameter, sufficient to contain a charge
that will of itself explode the torpedo (see Fig G), without depending
upon the priming case. The bolts are all the same size, and differ only
in the direction of the slot for safety key, being port or starboard
bolts accordingly.

[Illustration: (G)]

[Illustration: (H)]

The muzzle of the exploding bolt stands one inch off the pin when in
safety position, that is, when the safety key rests on the brasswork of
the priming case. This can always be ascertained before entering the bolt
(if thought necessary) by a wooden gauge forced down until it touches the
point of the pin, which measurement transferred to the bolt will show the
distance of the muzzle when forced down to the safety position.

The safety key is secured in the slot of the exploding bolt by eight or
nine parts of strong whity-brown thread secured to the key, as shown
in Fig. J (p. 10), passed round the bolt, and securely knotted in this
manner; the parts of the thread come away with the key when drawn,
in order that none of the parts may be worked down the tube by the
exploding bolt.

[Illustration: (I)]

[Illustration: (J)]

In the event of the large torpedo being cut away in deep water after
withdrawal of the safety key, it will explode by pressure on the head of
the bolt at about sixty fathoms depth. The small one at about thirty.

The brass guard for the exploding bolt is an extra precaution (suggested
by Capt. A. Hood, R.N., Director-General of Naval Ordnance) should any
person by mistake attempt to place the bolt into the torpedo without
the safety key in its place. It is placed over the head of the bolt and
pushed down until the thumb-screw on the side works into a small hole in
the shoulder of the bolt.[1] The manner in which this guard is fitted
ensures its removal before launching, since the after lever cannot be
placed until it is. It also makes a convenient handle for turning the
bolt in the magazine.

[1] As the certainty of explosion depends mainly upon the exploding
bolt being properly charged, the inventor takes entire charge of this
important detail.

[Illustration: (K)]

The explosive composition in the bolts is powerful and safe; so packed
that no amount of concussion can explode it; the bolt must be pierced
through the capsule at the muzzle for that purpose. The bolts are
hermetically sealed at the muzzle by a metallic capsule, and can be
stored for an indefinite length of time without chance of deterioration.
The exploding point of the composition in the bolt is 420° Fahrenheit.

[Illustration: (L)]

The side and top levers are so arranged, that when driven close into
the torpedo, the bolt is down to the shoulder; and, since there are
three explosions to take place, it is calculated the torpedo will be in
hugging contact when the main charge explodes, and exploded by a powerful
discharge in the centre, thereby disposing of the explosive force to the
greatest advantage.

The torpedo must be closing to the ship when the levers are acting and
the bolt descending; no experiment for the force of explosive agents,
with a cushion of water intervening, is required. The amount of explosive
agent, when in contact, is all that is required, and the torpedo can be
manufactured to contain a larger charge, if thought necessary, with a
very small increase of dimensions; but the present size is convenient for
handling and launching; and if loaded with any of the powerful blasting
powders, would, in all probability, prove sufficient to bilge or destroy
the largest iron-clad.

[Illustration: (M)]

[Illustration: (N)]

The lanyard or side-lever is permanently secured to the short arm of the
lever; the end is rove under the fair lead on the deck of the torpedo
up through the brass oval hole in the after top lever, then down under
the fair lead (abaft the first turn), and across the deck of the torpedo
to the handle, and secured with a round turn and two half-hitches. Care
should be taken that the short arm of the lever is brought close into
the fair lead, and the lanyard should be set up sufficiently taut to
give a slight spring in the after top lever by the strain brought on it.
This lever has a steel fish on the top, in order to prevent it taking
a permanent bend. If the side-lever lanyard is properly set up, the
bolt will spring down about one-eighth of an inch when the safety key
is withdrawn, owing to the spring in the lever and shrinking of the
lanyard; this brings the muzzle one-eighth of an inch nearer the pin
without disturbing the side lever. The lanyard should be made up like a
reef-point; it should be well-greased immediately before launching.

[Illustration: (O)]

[Illustration: (P)]

[Illustration: (Q)]

To secure the fore top lever to the after, in order that a back hit
may not separate them, the small lanyards, with an eye in one end, and
whipped at the other, are first placed over the eyes in the fore top
lever, then rove through the brass hole in the after top lever, in
opposite directions, passed up through the eyes in the fore top lever,
and knotted over it. The distance from the eyes in the fore top lever
to the hole in the after top lever is so arranged that it will not
interfere with the descent of them. The fore-locks for the various bolts
which fix the levers are made of fishing-line. After knotting them, the
ends should be secured together by a seizing of thread.

[Illustration: (R)]

[Illustration: (S)]

The handles, formed of iron straps passing under the torpedo, and
terminating in four eyes above the deck, are principally for handling it;
one of the foremost eyes is made use of as a fair lead for the safety-key
lanyard, and to stop it to; the other foremost is made use of to secure
the side lanyard to Fig. N (p. 12).

The ballast is composed of iron and sheet lead; the former, a fixture
to the wooden bottom of the torpedo; the latter, screwed on with long
screws into the iron. A thin sheet of lead is always kept on the
bottom, affording a soft material for moving them about on, removing
the objection that may be made to the friction caused by an iron bottom
in the moving of them in the torpedo-room. By taking out these screws,
several more thicknesses of sheet-lead can be screwed on, the same
screws binding all together. On leaving the manufacturers, there is
sufficient lead placed on the bottom for a speed between three and ten
knots. A very large increase of ballast would require another buoy to be
strung on over and above the usual complement.

[Illustration: (T)]

The proper adjustment of the slings is most important, as the divergence
depends upon it. The after legs of the slings, when stretched out
alongside the torpedo, should extend one foot beyond the stem iron of
the torpedo for the large torpedo, and eight inches for the small one;
the distance on the slings being reckoned from the seizing round the
thimble. This first adjustment is near enough if within two inches of the
regulation.

The thimble of the slings is made suitable for wire or hemp rope, the
fore surface of it being bell-mouthed, to prevent chafe of the tow-rope;
the thimble is so constructed that the parts of the slings cannot escape
from the groove should the seizing become slack; it will be observed that
by this arrangement the edge of the thimble is not brought in contact
when rounding the stem or stern of a vessel, the nip after leaving the
tow-rope coming direct on to the fore span, and thence to the projecting
curve of the side lever.

When all four legs are pulled out, in direction of the tow-rope, they
bear an equal strain; the junction of the four legs should be on a level
with the upper towing-irons, at the same time the upper fore span should
make an angle between 80° and 85° with the near side of the torpedo.
This arrangement gives the best divergence with the least strain on the
tow-rope, and is suitable when the torpedo is kept at short scope, as
well as when a long length of tow-line is out. The slings are made of
the best Italian hemp (not laid up too hard), the rope being of the same
strength as the tow-rope; for although in towing four legs divide the
strain, yet during collision the strain might be brought on one or two.[2]

[2] It may be here remarked, the small rudder on the stern of the torpedo
is not for the purpose of increasing the divergence, but to control the
direction of the torpedo when the tow-rope is suddenly slacked.

[Illustration: (U)]

[Illustration: (V)]

The tow-rope for large torpedo can be of 2½ in. or 3 in. hemp, or 1½ in.
flexible galvanized iron wire. For small torpedo, 1½ in. to 2 in. hemp,
or ⅞ in. wire.

The buoys are made of solid cork (such cork only being used as will
ensure great floating power after being immersed for a time), it is built
up on a galvanized iron tube, running longitudinally through; on the
ends of the tube are screwed wooden cones, which bind all together and
render the buoy indestructible. The iron tube gives great facility for
stringing on the number of buoys required.

[Illustration: DRAWING (W).

SECTION ON A B.]

Two buoys are generally used for the large torpedo, and one for the
small. The buoy-rope is of hemp, about five or six fathoms in length and
two inches circumference, an eye being spliced in the end nearest the
torpedo; to this eye is bent the tow-rope with a single or double sheet
bend, forming the knot by which the torpedo is towed; the other end of
the buoy-rope is passed through the large or small ring in the stern
(according to whether working in deep or shallow water), then through the
tube of the first buoy, an overhand knot made in the rear; then through
the next buoy, and a knot in the rear of that.

[Illustration: DRAWING (X).]

[Illustration: DRAWING 1.]

The brakes are used for the purpose of controlling the tow-ropes; they
can be fixed by screws into the deck at the most convenient place for
command, and, in a properly-constructed vessel, would be worked below the
water-line to prevent exposure of the men. They are so arranged as to
admit of the tow-rope being quickly veered, and at the same time powerful
in bringing the torpedo to the surface when required. Success greatly
depends on the skilful handling of these brakes, for in conjunction with
the cork buoys they give the operator command of the depth at which
the enemy is to be struck. The handles on the leather straps are for
the purpose of lifting the strap off the drum when veering suddenly,
that there may be no friction to interfere. The handles for winding
up would rarely be used in real action, and never should be on when
veering. Unless a very high rate of speed is required, one handspike
will control the tow-rope; the other strap can be thrown off the drum,
and the handspike allowed to lie on the deck ready to be thrown into
gear, if necessary. The surface of the drum in contact with the strap
should be powdered with rosin to increase the friction. The tow-rope
should be so reeled up, that in veering the reel may revolve towards the
men at the handspike (see Plate 2). The spindle will contain several
tow-ropes, that, in the event of one torpedo being cut away, another can
be immediately bent.

The brake for small torpedo requires only one drum and handspike. It can
be fitted to a steam-launch by placing an extra thwart across near one of
the others.

[Illustration: DRAWING 2.]

The drawing shows a small brake fitted for the electric torpedo, having
a hollow central spindle, through which the end of the tow-rope carrying
the insulated wire is rove, after passing out at the axle; a swivel
connection is made with the battery. The brakes, both large and small,
are so made as to ensure durability, they being considered a part of the
ship’s furniture.

Brake for safety-key line is a small reel on the same principle. When
going a slow speed, it may not be necessary, as the safety-key line can
be attended by hand; but when going ten or eleven knots, it will be found
of considerable advantage, both in keeping the light of the safety-key
line from dragging astern, thereby lessening the divergence of the
torpedo, and also in drawing the safety key when a strong stop is used.
The ordinary deep-sea lead line can be used for a safety-key line, or any
hemp-rope from three-quarters to an inch circumference. It should be new
and of good quality; for in the event of its carrying away before the
stop, it would necessitate the recovery of the torpedo.

[Illustration: DRAWING 3.]

[Illustration: (Y)]

The magazine for exploding bolts is fitted with exactly the same size
brass tubing as in the priming case; therefore, if the bolts are kept to
work with the proper pressure when in the magazine, they will do so in
the torpedo. This magazine should be kept apart from the torpedo-room,
and care should be taken that the tube is clear before forcing the loaded
bolt into it. The torpedoes are then no more dangerous than any other
powder case, and, being very strongly made and sealed, are probably less
so.

[Illustration: Plate 2.

Kell Bros. Lith. London.]


ARRANGEMENTS REQUIRED FOR LAUNCHING AND TOWING.

A yard across either the main or mizen mast of a torpedo vessel, from ten
to fifteen feet above the water-line, is a very convenient method for
launching and towing. The leading block on the yard, through which the
tow-rope is rove, may be fitted to a traveller on the yard with an inhaul
and outhaul, that the distance out from the ship’s side may be regulated
as convenient.

In a large vessel, the leading block for tow-rope can be fixed to the
end of the quarter-boat’s davits. The brakes for commanding the tow-rope
should be screwed firmly to the deck. In a vessel properly constructed
for the service, they would be on the lower deck, the tow-rope having
been led along the yard, and down each side of the mast.

A leading block for the tow-rope is placed on the deck by span or bolt
a few feet in front of the brake. The safety-key reel, if used, must be
fixed in a convenient position on deck, that the man attending it can see
how to control it; in a properly-constructed vessel he would be in the
pilot-house. The safety-key line leads through a small leading block on
the ensign-staff or some convenient point abaft the lead of the tow-rope,
that it may be kept well clear of it. The leading block on the yard may
be fitted with a lizard, if thought necessary. A sharp instrument should
be kept by the brakes ready to sever the tow-rope.


PREPARATIONS FOR LAUNCHING AND TOWING.

[Illustration: (Z)]

The torpedoes, port and starboard, loaded and ballasted, having been
hoisted out of the torpedo-room, are placed on the deck on their own
sides, with their heads forward under the leading block, and the number
of buoys required for each, placed abaft them, strung together as
directed (p. 17); the necessary number of exploding bolts having also
been taken from the bolt magazine, are now entered into the torpedoes,
and forced down until their safety keys rest on the brasswork, taking
care that each safety key points in the direction of the eye through
which its lanyard has to pass; the brass guard is now taken off, and
after top lever placed in the crutch of the exploding bolt; the fore top
lever is now placed on the shoulder of the after one, and the two levers
secured by their lanyards, as directed in pages 12 and 13. The eye at
the end of the buoy-rope is now rove through the large or small ring
in the stern end of the torpedo (see p. 17). The tow-rope having been
previously rove through the leading block on the deck and on the yard, is
rove through the thimble of the slings from forward aft, and bent, with a
single or double sheet bend, to the eye of the buoy-rope. The safety-key
line having been previously rove through the leading block on the
ensign-staff, and the lanyard on the safety key having been led through
the eye of the handle, making a fair lead with the slit in the bolt, are
bent together with a double-sheet bend, and stopped to the eye by a split
yarn of suitable strength, the yarn having been secured outside the bend.
It can also be stopped with another split yarn to the slings near the
thimble of the slings. The torpedo is now ready for launching.


LAUNCHING THE TORPEDO.

The crew having been stationed at their respective posts, the handles
having been shipped on the tow-reel, the tow-line is then reeled up until
the torpedo will launch clear, and swing out under the leading block on
the yard. Hold the torpedo by the handspikes, and take off the handles of
the brake. In swinging out, care should be taken that in starting from
the deck the fore slings do not foul the fore top lever. The stern of the
torpedo can be steadied by keeping a slight strain on the buoy-rope. The
safety-key line must be kept clear, and not checked, or it might break
the stop and draw the safety key before intended.

The buoys must be placed in a proper position, and hands stationed by
them to launch them overboard the instant the torpedo takes the water.
It would be better to stop the screw, if circumstances would allow of it,
when lowering the torpedo and buoys into the water, to prevent the chance
of the buoys fouling the screw. The torpedo, on reaching the water, will
_immediately_ diverge clear of the ship; the buoys being launched, as the
strain comes on the buoy-rope, they will be towed clear away from the
screw, and full speed may be put on at once. The men at the handspikes
must veer steadily, occasionally checking the torpedo, that it may be
kept near the surface, and not allowed to dive, which it will do if the
tow-rope is slacked up altogether, and then a sudden strain brought on it.

[Illustration: DRAWING 4.]

Eventually it will come to the surface, when the bow is pointed up by
the strain on the tow-rope; greater the speed the more quickly will it
be brought to the surface. In shallow water this should be particularly
attended to, as in diving it might strike the bottom and injure the
levers; and if the safety key has been withdrawn, explode; moreover it
brings an undue strain on the tow-rope. The torpedo can now be gradually
veered out to the distance required, the safety-key line so attended,
that a sufficient strain is kept on it as not to allow of a long bight
of line dragging astern of the torpedo; at the same time having due
regard to the strength of the yarn by which the line is stopped to the
handle of the torpedo. The distance veered must depend upon the nature
of attack. The tow-line should be marked with knots every ten fathoms;
under some circumstances the torpedo would be close to the ship until
passing the enemy (_see_ Tactics); at other times veered to 40 fathoms it
will be found most suitable. The full divergence of 45° is obtained up
to 50 fathoms, beyond that the bight of the tow-rope in the water drags
the torpedo astern unless the tow-rope is triced much higher up, which
has its disadvantage; 40 to 50 fathoms of tow-rope gives the best command
of the torpedo, veering 2 or 3 fathoms of tow-line suddenly will always
sink the torpedo some feet below the surface. Should it become necessary
to use the torpedoes with a stern-board they can be so used, but in
this case the port torpedo is used on the starboard bow and starboard
on the port; all other arrangements being exactly the same. In rough
weather, advantage should be taken of the roll, and the torpedo allowed
to swing out from the yard, and be let go by the run, checking the
tow-rope immediately the torpedo is in the water. It is not absolutely
necessary to ease the vessel when launching, the torpedo can be launched
at full speed. In the event of its being found necessary to cut adrift
the torpedo, in consequence of coming suddenly across a friendly vessel,
the tow-rope should be cut near the brake, and if the buoy-rope has been
rove through the large stern-ring, the torpedo will sink and be lost, the
buoy only remaining. If the buoy-rope has been rove through the small
stern-ring, the torpedo will be suspended by the buoy-rope; and should
the safety key not have been withdrawn, can be recovered with safety.
In the event of wishing to recover it when the buoy-rope has been rove
through the large ring, a toggle must be lashed on the tow-rope abaft the
leading block on the yard, when it can be recovered by the buoy-rope; as
a general rule, it will however be found best to expend the torpedo, and
not attempt its recovery. By slacking the tow-rope roundly and stopping
the vessel, a friendly ship can pass over the bight of the tow-rope
without striking the torpedo; but this is rather a delicate operation,
particularly if the safety key has been withdrawn.


RECOVERING THE TORPEDO.

Should the safety key have been withdrawn, great caution must be used.

[Illustration: DRAWING 5.]

Tongs, for going round the upper part of the bolt, to take the place of
the safety key, when once clasped and secured round the bolt, render the
torpedo safe to handle; this could only be done from a boat. With the
safety key in, there is no danger in hooking it inboard again by its own
tow-rope, and hoisting up the buoys at the same time with a grapnel.


TORPEDO ARRANGED TO EXPLODE BY ELECTRICITY.

To substitute the electrical method of firing the torpedo for the
mechanical one, all that will be necessary is to unscrew the priming
case from the centre hole of the mechanical torpedo, and screw in the
electrical arrangement which contains McEvoy’s patent circuit-closer,
especially adapted by him to suit this particular torpedo.

The electrical arrangement has its own exploding bolt, which differs
from the other only below the safety key, which key is fitted and worked
in the same manner as the mechanical one, in order that the electrical
arrangement might not be disturbed by an accidental blow when launching.
The insulated conducting wire is carried along the whole length of
the tow-rope in the centre, forming a core. The tow-rope, as in the
mechanical one, is bent on to the hemp buoy-rope by a sheet bend, the
strands at the end are then unlaid, sufficiently so to form a connection
between the insulated wire in the tow-rope and that projecting from
the centre hole of the torpedo; this connection can be best made with
McEvoy’s patent jointer. The other end of the tow-rope on the barrel of
the brake passes through the hollow spindle of the brake at one extremity
and is connected with the constant battery, which must be suitable for
heating platinum at the distance of 100 fathoms, the return circuit being
by the water. The levers act in the same manner as in the mechanical one,
forcing down the bolt and thereby closing the circuit through the fuze
and exploding the torpedo.

This system of exploding the torpedo may be preferred in rivers or
shallow water, where it would be considered dangerous to leave a
mechanical torpedo at the bottom; but it cannot be reckoned upon with
the same certainty as the mechanical one. It is necessarily more costly,
complicated, and delicate; the two latter conditions rendering it
unsuited for the rough work it will have to encounter.

The torpedo being provided with this centre tube in addition to the
usual priming case, admits of its being used upon an emergency, special
ones not being at hand, for various other purposes, _viz._ clearing
away obstructions; as land torpedoes; as stationary torpedoes, provided
they are not to remain a very long time in the water. In these cases
the ordinary insulated wire and jointers are all that is required. If
required to be fired at will, it will be only necessary to force down the
bolt sufficiently to close the circuit through the fuze and then secure
it. If to be self-acting, leave the bolt up in its position, as when
working at sea, to be acted upon by pressure.


DESCRIPTION OF CAPT. C. A. MCEVOY’S CIRCUIT-CLOSING ARRANGEMENT FOR
HARVEY’S SEA TORPEDO.

[Illustration: _Fig: 1._ _Fig: 2._

London: E. & F. N. Spon, 48, Charing Cross.

Kell Bros. Lithrs.

FIG. 1.—An exterior tube, _a a_; screw-head, [= _a_]; interior tube,
_b_; intermediate tube, _d_; firing bolt, _e_; spindle, _f_; long brass
spiral spring, _g_; short spiral spring, _h_; socket for spindle, _i i_;
insulated wire from battery, _k k_; insulated terminal, _l_; electric
fuze, _m_; priming space, _n n_; charging hole, _o_; insulated bridge,
_p_; metal bridge, _u_.]

The electric wire _k k_ passes through the screw-head [= _a_] of external
tube _a a_, and winding spirally around the intermediate tube _d_,
terminates in a connection with the insulated bridge _p_ at _s_. The
intermediate tube _d_ is attached to the head of the spindle _f_ at _t_.
When pressure is brought to bear on the firing bolt _e_, the spindle _f_
is forced down, and carries with it the insulated bridge _p_, until the
bridge touches the insulated terminal _l_. It will be seen that the
long spiral spring _g_ and short spiral spring _h_ serve to support
the spindle _f_, and keep the bridge _p_ off the terminal _l_ until
they are forced into contact. Whilst the insulated bridge _p_ remains
above the insulated terminal, the former is in constant contact with
the metal bridge _u_; but this contact is broken when the metal bridge
moves downward and before it makes contact with the insulated terminal
_l_. When the insulated bridge _p_ is in contact with the metal bridge
_u_, the electric fuze is out of circuit; and a current sent through
the torpedo will return by way of the earth without firing the torpedo;
but when contact with the metal bridge _u_ is broken, and contact with
the insulated terminal _l_ is made, the current is directed through the
electric fuze, and the torpedo fired.

The priming in the tube is sufficient to rupture the tubes and ignite the
charge in the torpedo.

Fig. 2 shows a section of the circuit-closer, with the spiral spring
slightly compressed, and the insulated bridge in contact with the
insulated terminal, and the circuit closed. By dispensing with the
electric fuze, and using in its place a piece of copper wire, any number
of experiments may be made with an uncharged torpedo without adjustment
or manipulation of any kind; it only being necessary to attach to the
return wire near the battery a galvanometer or electric fuze to indicate
the time of the impact.

    The torpedoes here described are manufactured by J. Vavasseur
    and Co., at the London Ordnance Works; at which establishment
    the inventor has every facility in the supervision of the
    various details in the construction of the torpedoes, buoys,
    and brakes. Such supervision of the torpedoes and their
    equipments is highly essential to secure safety and efficiency.




TACTICS.


Torpedo vessels should, as a rule, attack under the cover of darkness. By
the experience gained in blockade running in the late American conflict,
we are assured that a vessel in rapid motion can, when it is dark, pass
with impunity close under the fire of hostile vessels, armed with cannon.

In the more early stage of the torpedo, the tactics of vessels armed
with torpedoes embraced modes of attack that are not now entertained. So
general is becoming the use of torpedoes as a means both of defence and
offence, that vessels, which may be at anchor or moored in a harbour or
roadstead, would be protected by stationary torpedoes; the use of which
admits also of vessels, when at anchor or moored, protecting themselves
by placing a web of torpedoes in such manner as to render the attack
of a hostile vessel or boats extremely hazardous, and therefore not
likely to be attempted. But in the event of a vessel being at anchor in
a harbour or roadstead unprotected, she could be attacked, as shown in
the illustration of Tactics, under such conditions. As, however, vessels
armed with torpedoes are intended to work the arm against vessels at sea
or in motion, the management of the torpedo in so attacking vessels is
the more important part of the code of Tactics.

It should be here remarked, that with a view to simplicity, the
explanations will be confined to a single steamer, the attacking vessel
adapted to the service of the arm in question, and confined also to a
single vessel, the object of attack.




CASE 1.

ATTACKING A VESSEL MOORED HEAD AND STERN.


In this case the torpedo vessel steers in for the bow or quarter of
the vessel attacked, according to the direction of the current, and on
the side approached launches the torpedo between the moorings as at A;
leaving the tow-rope slack, the torpedo vessel proceeds ahead or astern
against the current, and when at a sufficient distance off, the tow-rope
is held fast, which will cause the torpedo to diverge into contact with
the vessel attacked, as shown by the drawing.

[Illustration: Plate 4.

Kell Bros. Lith. London.

CASE 1.—ATTACKING A VESSEL MOORED HEAD AND STERN.]




CASE 2.

ATTACKING A VESSEL AT ANCHOR BY CROSSING THE BOW.


In this case, the torpedo is sufficiently diverged when near to the
vessel with a good scope of tow-rope out. After having crossed her bow,
proceeding onwards, the tow-rope will be brought obliquely across her
cable, and the torpedo will swing into her, as shown in the drawing. It
may be here remarked that, in all cases, the depth of explosion can be
obtained by the sudden slacking of the tow-rope; and the tow-rope, once
under the keel, causes the torpedo to be hauled down near to it before
exploding.

[Illustration: Plate 5.

Kell Bros. Lith. London.

CASE 2.—ATTACKING A VESSEL AT ANCHOR BY CROSSING THE BOW.]




CASE 3.

ATTACKING A VESSEL AT ANCHOR BY PASSING ON EITHER SIDE DETERMINED UPON,
COMING UP FROM THE STERN.


In this case, the torpedo is launched when on the quarter of the vessel
attacked, as at A, the tow-rope left slack. After steaming ahead some
distance, hold fast the tow-rope, when, by continuing to steam on,
the torpedo will diverge into contact with the bottom of the vessel
attacked, as shown in the drawing. _When skilfully performed_, the total
destruction of the enemy is certain, since the torpedo is springing
from a depth to the surface, and will, in consequence, strike near the
keel. The torpedo vessel can pass at her greatest speed, and, if thought
necessary, near enough to clear away any of the ordinary obstructions,
such as booms, nets, &c.

[Illustration: Plate 6.

Kell Bros. Lith. London.

CASE 3.—ATTACKING A VESSEL AT ANCHOR BY PASSING ON EITHER SIDE.]




CASE 4.

ATTACKING A VESSEL AT ANCHOR BY COMING UP RIGHT ASTERN AND THEN PASSING
ON EITHER SIDE.


In this case, having determined upon the side it is desirable to pass,
a torpedo is launched accordingly. When near the vessel, the torpedo is
sufficiently diverged, and the torpedo vessel passing onwards ahead, the
torpedo is brought under the run or bottom of the vessel attacked, as
shown by the drawing.

[Illustration: Plate 7.

Kell Bros. Lith. London.

CASE 4.—ATTACKING A VESSEL AT ANCHOR COMING UP FROM ASTERN AND THEN
PASSING ON EITHER SIDE.]




CASE 5.

PASSING DOWN BETWEEN TWO LINES OF VESSELS AT ANCHOR, AND DESTROYING THEM
ON EITHER SIDE.


In this case, it would be impossible to fire at the torpedo vessel for
fear of injury to their friends. Two or more torpedo vessels following
each other with preconcerted signals would cause great destruction.

[Illustration: Plate 8.

Kell Bros. Lith. London.

CASE 5.—PASSING BETWEEN TWO VESSELS AT ANCHOR.]




CASE 6.

ATTACKING A VESSEL IN MOTION BY COMING DOWN FROM RIGHT AHEAD.


In this case, two torpedoes are launched, port and starboard, each
diverging to its full extent; when passing the vessel attacked, one
or the other of the tow-ropes is brought across the cut-water, and by
the simultaneous motion of the two vessels in opposite directions,
the torpedo is brought alongside of or under the bottom of the vessel
attacked, as shown by the drawing. The torpedo vessel should keep the
masts of her enemy in one until close to, when either torpedo will be
used, according to the movement of the enemy. At the time of the tow-rope
taking the cut-water, the brake is suddenly eased up; the tow-rope will
then pass under the bottom, when, by checking the tow-rope, the torpedo
will be hauled under the bottom.

[Illustration: Plate 9.

Kell Bros. Lith. London.

CASE 6.—ATTACKING A VESSEL IN MOTION COMING DOWN FROM AHEAD.]




CASE 7.

ATTACKING A VESSEL IN MOTION, COMING UP TO HER FROM RIGHT ASTERN.


In this case, two torpedoes are launched and diverged, as in Case 6;
and in this case it is assumed that the torpedo vessel can outspeed the
vessel attacked, which will enable her to bring a torpedo under the run
of the vessel attacked, as shown by the drawing.

[Illustration: Plate 10.

Kell Bros. Lith. London.

CASE 7.—ATTACKING A VESSEL IN MOTION COMING UP FROM ASTERN.]




CASE 8.

IF CHASED BY A HOSTILE VESSEL, AND IT IS DEEMED UNADVISABLE TO FACE HER
AND PROCEED AS IN CASE 6.


In this case, veer a torpedo astern, having first obtained a position
a little on the bow of the chasing vessel. When it is known, by the
length of the tow-rope out, that the torpedo is about abreast of her bow,
hold fast the tow-rope, which will cause the torpedo to diverge, and be
brought into contact, as shown in the drawing. As a last resort, drop
spanned torpedoes.

[Illustration: Plate 11

Kell Bros. Lith. London.

CASE 8.—CHASED BY A HOSTILE VESSEL.]




CASE 9.

ATTACKING A VESSEL IN MOTION BY CROSSING HER BOW.


In this case, the torpedo being diverged when near, will, after crossing
the bow, be dragged into contact, as shown by the drawing.

Torpedoes can be used with a stern-board, if necessary. The port torpedo,
in this case, will be launched on the starboard side, and the starboard
on the port side.

[Illustration: Plate 12

Kell Bros. Lith. London.

CASE 9.—ATTACKING A VESSEL IN MOTION BY CROSSING THE BOW.]




In conclusion, it should be stated that a dark night and tempestuous
weather are in favour of the attacking torpedo vessels; and these
conditions are especially advantageous when attacking large, long,
unwieldy vessels, and the greater the number of them together, the
more easily can they be disabled or destroyed, by reason of consequent
confusion. Though the sea torpedo can be used in the light of day, or
darkness of night, by vessels of the present navies, armed with cannon,
it is nevertheless earnestly advised that fast vessels be built of
comparatively small size and cost, adapted to the service of and armed
with torpedoes, by reason that such vessels can keep at sea for long
periods without replenishing supplies of coals and provisions; and
in conflict upon the ocean, can easily destroy or render unseaworthy
vessels, how large soever they may be, and armed with any cannon and
projectiles at present known. Hence the necessity of being prepared
with vessels suited to the change in naval warfare, and with officers
well practised in an arm which, sooner or later, will be adopted by
all Maritime States, by reason of its economy and efficiency. In the
tactics, here attempted to be rendered intelligible, it is presumed that
the various modes of attack are by small handy vessels adapted to the
service, and armed with torpedoes, against large unwieldy vessels, armed
with cannon. When it shall have been clearly demonstrated, in actual war,
that large vessels can be disabled or destroyed by small vessels, with
something like impunity, torpedo warfare will then take another form,
that of torpedo vessels against torpedo vessels, whose tactics will, in
due time, be a subject for another study.

                                                        FREDERICK HARVEY,
                                                        _Commander R.N._




THE SUBJOINED IS A REMARK UPON THE DESCRIPTION OF VESSEL ADAPTED TO THE
SERVICE OF THE SEA TORPEDO.


Vessels adapted to the service of the sea torpedo should be about 400
tons burthen; her extreme length, over all, from taffrail to figure-head,
about 150 feet. The form of body to be such as to attain the greatest
practicable speed.

Speed being the essential condition of a torpedo vessel, a perfectly
flush upper or weather deck, without any bulwarks, is advisable; instead
of bulwarks, life-lines, supported by stanchions, supply their place
to prevent accidents of falling overboard. Thus fitted, there would be
nothing to hold wind that could retard speed, as there is in vessels of
ordinary build. So covered in, the vessel would not, under any condition
of weather, ship water; she would not, from such cause, be in any danger
of foundering.

The height of the weather-deck above the water-line at midships, 9 feet;
the height of the main deck above the water-line, 18 inches; leaving
a clear height between decks of 6 feet 6 inches. There should be two
water-tight bulkheads, one about 50 feet from the stem, and the other
about 20 feet from the stern-post; the two water-tight bulkheads come
up to the under side of the main deck, with which the bulkhead form
perfectly water-tight compartments. In the fore compartment, empty
water-tight cases would occupy the lower part, over which would be stowed
the cork buoys and some light resisting material, rendered uninflammable,
so that in the event of the fore body being ripped open below the
water-line, there would be no space for the admission of water; the
trim of the vessel would therefore be preserved. The after compartment
would be similarly stowed. There would be a capacious engine-room to
allow of powerful engines to work twin screws; there would also be
capacious coal-bunkers and a coal-hold before the engine-room; and
before the coal-hold a small hold for the stowage of cables and various
articles. There would also be a pilot-house, in which would be protected
the officer in command, who would be so placed as to have his orders
immediately obeyed. The torpedo-room, to contain about one hundred
torpedoes of various destructive powers, the weight of which may be
about 10 tons, would be in the after body, and as low down as may be
convenient. Upon the orlop deck, which covers the magazine, would be the
towing gear, and machinery for working such gear. On the orlop deck would
also be a steering wheel, by which the vessel would be steered when in
action. The space between the decks of the entire length of the vessel
would afford ample accommodation for officers and crew, embracing, also,
stowage for provisions and means of cooking. Ventilation and light would
be obtained by hatchways, fitted with skylights; and there would also be
side scuttles, which, from their height above water, would admit of their
being generally open. The rig would be that of a three-masted schooner,
having fore, main, and mizen gaffsails, with a fore staysail and two
jibs, inner and outer. When going into action, the sails would be lowered
and stowed; the vessel would then be entirely under steam. To each mast
there would be a yard of suitable dimensions, for the double purpose of
towing the torpedoes and setting flying square sails. The rigging would
not be rattled; the ascent to the masthead would be by a Jacob’s ladder
before the mast; there would be a small top to each masthead, principally
for the use of the look-out men. The crew would be stationed upon the
orlop deck, each man being provided with a life-belt. With regard to
boats, there may be a small stern boat, and two larger boats, stowed on
deck; and upon going into action, gripes or lashings should be cast off
so that the boats would instantly be disengaged from the vessel.

Torpedo vessels for foreign service should, under the present
difficulties of keeping iron from oxidizing and fouling, be built
of timber. For home service, vessels constructed of iron would be
preferable, and with very reduced masts, to enable them to pass under the
yards of a vessel. One or two light guns, to bring-to an unarmed vessel,
and for signal purposes, on the weather-deck, and fired over all.

[Illustration: Plate 3.

Kell Bros. Lith. London.

AN IRON CLAD FLEET SURPRISED AT SEA BY A SQUADRON OF TORPEDO CRAFT ARMED
WITH HARVEY’S SEA TORPEDOES.]


LONDON: PRINTED BY WILLIAM CLOWES AND SONS, STAMFORD STREET AND CHARING
CROSS.