IMPROVEMENTS IN THE CONSTRUCTION OF ARMOUR FOR SHIPS OF WAR AND LAND BATTERIES
Year: 1863

page_text: LETTERS PATENT to Thomas Symes Prideaux, of 209, Piccadilly, in the
County of Middlesex, for the Invention of "IMPROVEMENTS IN THE
CONSTRUCTION OF ARMOUR FOR SHIPS OF WAR AND LAND BATTERIES."
Sealed the 6th May 1864, and dated the 14th November 1863.
PROVISIONAL SPECIFICATION left by the said Thomas Symes Prideaux
at the Office of the Commissioners of Patents, with his Petition, on the
14th November 1868.
I, THOMAS SYMES PRIDEAUX, of 209, Piccadilly, in the County of Middlesex,
do hereby declare the nature of the said Invention for "IкPROVEMENTS IN
THE CONSTRUCTION OF ARMOUR FOR SHIPS OF WAR AND LAND BATTERIES," to be
as follows:-
This Invention has for its objects to increase the power of armour to resist
projectiles, and also to increase its durability, by embodying in a practical
form the principle heretofore enunciated by me, that the armour should be so
fixed as to allow it to recede a certain distance upon the impact of a projectile,
so that when finally brought up it will have to withstand only the residuary
instead of the initial velocity of the shot, that is to say, a force less than the
original force by all the force expended in giving motion to the target; by
substituting for the practice of boring holes in the armour plate for its attach-
ment a system of fastening by studs or eyes formed on, welded to, or soldered
on to the inner side of the plate; by subjecting the plates after the last heating

page_text: to repeated hammering during the process of cooling, by which the extent to
which they assume a crystalline structure will be lessened, iron plates will
thus be toughened, and the greater tenacity of the material known as soft
steel may by this process be rendered available; by enclosing the plates in a
covering impervious to wet; in addition to which, when used at the sides of
ships, I prefer to construct the ships with a double skin throughout the extent
to be defended by the armour plating, which is to be fixed between the two.
These objects are to be attained as follows:-Each armour plate, with or
without wooden backing, is suspended. by rods, the upper ends of which are
attached by pin joints to ribs or beams fitted with eyes or studs on the face of
the battery to be protected, and the lower ends by pin joints to the lower
portion of the inner side of the armour plate, which is also to be furnished
with studs or eyes for the purpose. Thus freely suspended from a vertical
face, and checked from turning over, and kept rather within the perpendicular
by the means hereafter to be described, it is evident the plate would by its
own gravity tend to descend to the lowest attainable position, that is to say,
would hang resting against the face from which it is suspended. Each armour
plate is to be further secured to the face which supports it, and which it
protects by four or more flexible ties, which may either be iron chains, or
hempen or other cables affixed to eyes on the exterior of the protected face
on the one hand, and on the inner side of the armour plate on the other hand,
which ties are to be just of such a length as to allow of the armour plate
being drawn from the face of the battery the distance at which it is proposed
to keep them apart. It is to be kept at this desired distance by the insertion
between the two of vulcanized india-rubber, or other elastic material, such as
woollen rags or hair, or blocks of vulcanized india-rubber may be used, and
the spaces between fitted with cushions stuffed with woollen rags or hair, or
equivalent elastic material, which latter is the plan I prefer. The flexible ties
being kept tightly strained by the elastic blocks or cushions, the armour plate
will be strongly and steadily, though elastically fixed, so that when attached to
vessels it will be capable of being subjected to all the vicissitudes of a stormy
sea without being liable to the straining caused by jerking or shaking. When
space will permit, I prefer attaching to the front side of the armour plating a
layer of elastic substance to receive the first impact of the shot, that so the
plate may be deprived of its vis inertiæ, and put in motion before its actual
contact with the shot.
The toughening the armour plates by hammering I effect thus:-For the
anvil I employ the head of a piston fitted in a very large cylinder containing
water for the hammer I use a very heavy steam hammer, arranged tp

page_text: traverse on a railroad above the anvil. When the plates are required to be
curved, the required curvature may be conveniently given to them during this
process. For this purpose a floor of sand contained in a flat bottomed trough
is placed upon the head of the piston, and on the sand an iron moulding block
of the curvature required, which thus becomes the anvil on which the plate is
moulded. When armour is used for land batteries, I prefer to enclose each
plate with its attachments in sheet lead, or zinc, or copper, and exclude the
air by soldering together the edges of the plates. When used for the sides of
ships, in addition to covering each plate with a closely investing waterproof
wrapper, I prefer to construct the ships with an outer and inner skin
throughout the extent to be defended by the armour plating, which is to
be fixed between the two. An outer skin co-extensive with the armour
plating is not, however, absolutely indispensable, the edges of the armour
plates may be caulked, and the exterior covered with waterproof felt or
canvas; or each plate with its attachments may be soldered up in a thin
metallic covering, as for land batteries.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Symes Prideaux, in the Great Seal Patent Office on
the 14th May 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
SYMES PRIDEAUX, of 209, Piccadilly, London, Civil Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourteenth day of November, in the year of our
Lord One thousand eight hundred and sixty-three, in the twenty-seventh year
of Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said Thomas Symes Prideaux, Her special licence that I, the
said Thomas Symes Prideaux, my executors, administrators, and assigns, or
such others as I, the said Thomas Symes Prideanx, my executors. adminis-
trators, and assigns, should at any time agree with, and no others, from
time to time and at all times thereafter during the term therein expressed,
should and lawfully might make, use, exercise, and vend, within the United
Kingdom of Great Britain and Ireland, the Channel Islands, and Isle of
Man, an Invention for "IMPROVEMENTS IN THE CONSTRUCTION OF ARMOUR FOR
SHIPS OF WAR AND LAND BATTERIES," upon the condition (amongst others) that
I, the said Thomas Symes Prideaux, my executors or administrators, by an
instrument in writing under my, or their, or one of their hands and seals,

page_text: should particularly describe and ascertain the nature of the said Invention,
and in what manner the same was to be performed, and cause the same to be
filed in the Great Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Thomas Symes Prideaux, do hereby
declare the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement:-
This Invention has for its object to increase the invulnerability and durability
of armour, more particularly by embodying in a practical form the principle
heretofore enunciated by me, that armour should be so fixed as to allow it to
recede a certain distance upon the impact of a projectile. When a projectile
penetrates any resisting surface, it does so by virtue of its force or mechanical
effect overpowering the attraction of cohesion in the particles of the opposing
body. A projectile can only be arrested by its force or mechanical effect
being expended, i.e,, transferred to the resisting medium, whence it follows
that the power of any given target to resist any given projectile must be
inversely as the concentration of the transfer of the mechanical effect of such
projectile, or directly as the mass of matter receiving and the time occupied in
expending its force. Hence, in proportion as we oan succeed in prolonging
the time of transfer shall we succeed in lessening the necessary thickness of
the target to resist any given projectile, or in prolonging the durability of any
given target. This desideratum is only to be attained by constructing the
target so as to allow of its receding upon the impact of the projectile. The
more rigid the target, the more instantaneous the transfer, the more violent
the shock, and the greater the required thickness of target to resist a given
projectile. Whereas by the target receding a certain distance upon the
impact of the projectile, the force ultimately to be overcome will be only the
residuary instead of the initial striking force of the projectile, that is, the initial
striking force minus all the power expended in giving motion to the target.
The expedient of lessening the strain to which a structure is subjected in
encountering the vis viva of a moving body by prolonging the time occupied
in bringing it to rest, or in other words, the principle of lessening shocks by
the gradual arrest of momentum is one extensively employed by nature in the
structure of animals. In short, the truth of the principle appears to me self-
evident, and were it not instinctively acted upon by living beings, perpetually
recurring injuries to their bodies would be the result. The school-boy who
kept bis arms rigidly extended to catch a cricket ball would probably have his
metacarpal bones fractured, and the sportsman who in jumping off a hedge

page_text: kept his legs straight, and came to the ground on his heels, would run the risk
of being crippled for life.
According to my views, an armour protected structure should consist of two
essentially distinct parts, a yielding face and a supporting back. The first, a
series of detached targets, so fixed as to be capable of receding a certain
distance upon the impact of the projectile; the outer surface of this moveable
target should be tenacious, not brittle; but the structure as a whole must
possess sufficient stiffness and rigidity not to buckle under the blow of the
projectile. Caeteris paribus, the greater the distance through which it is
capable of receding, the less its necessary strength. The second and inner
self-supporting structure continues throughout strong enough to sustain the
weight and strain of the detached targets suspended from it, and also to resist
their pressure or support their impact when receding before the blow of a
projectile.
I carry out these principles as follows:-I enclose the armour plate in a
waterproof covering for its preservation, and when space will permit, I cover
its outer face with a layer of plaited hemp, (or hair, or wool, or other equivalent
material possessing the requisite elasticity and tenacity made up of a succession
of thin layers,) to receive the first impact of the projectile, so that the plato
may be deprived of its vis inertiæ, and put in motion before its actual contact
with the projectile. When space will not admit of this appliance being used,
I prefer the face of the armour plate to be made with a number of salient
points or ridges. By the use of wooden backing, and a moderately thin
armour plate, the requisite stiffness and strength to prevent buckling or
penetration may be obtained with a less weight than when iron alone is used,
but greater thickness of material, and consequently more space will be
necessary in the former case. When this cannot be afforded, the extra thick
armour plate required should have its outer portion of soft iron, and its inner
portion of steel. When I use backing I employ a cellular structure of iron
or steel, consisting of a series of hexagonal cells like a honeycomb, each cell
being filled with a hexagonal plug of compressed wood, or any fibrous material,
such as hemp, or cocoa-nut fibre, compressed to the size and shape of the cell
in a mould. The sides of the cells should be from 1 to 2 the thickness of
the armour plate, and the bottom twice or thrice the thickness of the sides.
Their depth should be about three or four times the thickness of the armour
plate, and their diameter about or of their depth. The honeycomb
structure may be made of malleable cast iron, or cast in soft steel, and
annealed, or constructed of wrought iron by bending stringers of this metal so
as to form a series of equidistant angles of 120°, and then rivetting them

page_text: together by connecting pieces, as shown in Fig. 3, and employing a separate
plate for the bottom or back, which in this case should be proportionately
thicker; but I prefer to construct a cellular network by casting when the
sides of the cells are thick enough to admit of doing so. As a substitute for
the difficulty of manufacturing plates of a certain size, two, or even three
plates may be united, so as to form one moveable target. Each armour plate
(whether with or without wooden backing) is suspended by rods or cables,
the upper ends of which are attached by pin joints to ribs or beams fitted with
eyes or studs on the face of the battery to be protected, and the lower ends by
pin joints to the lower portion of the inner side of the armour plate, which is
also to be furnished with studs or eyes for the purpose. Thus freely suspended
from a vertical face, and checked from turning over by the means hereafter
to be described, it is evident the plate would by its own gravity tend to descend
to the lowest attainable position, that is to say, would hang resting against the
face from which it is suspended. Each armour plate is to be further secured
to the face that supports it, and which it protects by four or more flexible ties
(which may either be iron chains, or hempen or other cables, I prefer cables
or bands of vulcanized indian-rubber,) affixed to eyes on the protected face on
the one hand, and on the inner side of the armour plate or of the cellular
backing on the other hand, which ties are to be of just such a length as to
allow of the armour plate or target being drawn from the face of the battery
the distance at which it is proposed to keep them apart. It is to be kept at
this desired distance by the insertion between the two of vulcanized indian-
rubber, or other elastic material, such as wool, or hair, or steel springs, or
blocks of vulcanized indian-rubber may be used, and the spaces between fitted
with cushions stuffed with elastic material. The flexible ties being kept
slightly strained by the elastic blocks or cushions, the armour plate or target
will be strongly and steadily, though elastically fixed, so that when attached to
vessels it will be capable of being subjected to all the vicissitudes of a stormy
sea without being liable to the straining caused by jerking or shaking.
The mode of construction will be readily understood by reference to the
accompanying Drawings and description.
DESCRIPTION OF DRAWINGS.
Fig. 1 is a vertical section of the target through the line A, B, in Fig. 2;

page_text: Fig. 1, a, layer of plaited hemp; b, the armour plate; c, investing water-
proof wrapper; d, cellular backing; e, layer of plaited hemp, which acts as a
cushion when the target is driven back the whole of its available distance by
the blow of a heavy projectile; f, vulcanized indian-rubber buffer. These
buffers are hollow, the end of a bolt passes into the centre of each, thus
keeping it in its place, and serving at the same time for the attachment of the
cord or rope, which, kept in a state of tension by the elasticity of the buffer,
gives consistency to the fabric, and firmly unites the two portions into one
strong yet elastic whole. The continuation of the buffers to the skin of the
vessel (or face of the battery) is shown by dotted lines; 9 shows the fastening
of the sustaining cord or rope on the further side; h represents a space of six
inches divided into compartments by ribs of iron, as shown by the dotted
lines r,, in Figure 2, which compartment are filled up with blocks of
wood ; 9, except the compartments 8, s, required for the suspending rods, and
the compartments t, t, required for the buffers. Cavities also require to be
made in the wood blocks at u, u, to receive the ends of the iron bolts. The
ear piece p and frame p¹ are to be one forging; v is a tie rod, which in the
case of a vessel passes from side to side, thus opposing the strain of one ear
piece by that of the other; i, skin of the ship (or face of the battery). The
side of the ship or battery behind i may be made of any requisite strength,
and requires no special description. j,j, are stout bolts, by which the armour
plate and cellular backing are firmly bound together; K, K, are the holes in
the tops of these bolts for the attachment of the ligatures or uniting cords;
7 shows the compressed wood with which the cells of the backing are filled;
m, the sides of the hexagonal cells; n, suspending rod or cord of steel wire
rope; o, ear piece for attaching suspending cord to armour plate. I prefer
that this ear piece should be forged or rolled in one with the armour plate,
but it may be attached by bolts. In Fig. 2 similar letters are used to
indicate similar parts of the structure. Fig. 3 shows the mode of constructing
the cellular backing when made of wrought iron.
When armour is used for land batteries I prefer to enclose each target with
its attachments in sheet lead, or zinc, or copper, and exclude the air by
soldering together the edges of the plates, thus preventing the risk of their
destruction by oxydation. When used for sides of ships, in addition to
covering each plate with a closely investing waterproof wrapper, I prefer to
construct the ships with an outer and inner skin throughout the extent to be
defended by the armour plating, which is to be fixed between the two; an
outer skin co-extensive with the armour plating is not, however, absolutely
indispensable; the edges of the armour plates may be caulked, and the

page_text: exterior covered with waterproof felt or canvas, or each target with its attach-
ments may be soldered up in a thin metallic covering, as for land batteries
and the edges of the cases united at the exterior by soldering strips of metal
between them, or shallow grooves being formed on the edges of the armour
plates, cords of vulcanized indian-rubber may be forced through the exterior
slit, which expanding into the grooves will be securely retained in position,
and by forming the cords of the following section
the flat portion
will close the space between the edges of the plates on the exterior.
Having thus explained the nature of my Invention, I wish to observe that
in carrying out its principles I do not limit myself to the precise details and
dimensions herein shown and described.
In witness whereof, I, the said Thomas Symes Prideaux, have hereunto
set my hand and seal, this Fourteenth day of May, in the year of our
Lord One thousand eight hundred and sixty-four.
THOMAS SYMES PRIDEAUX. (L.S.)