IMPROVEMENTS IN THE USE, APPLICATION, AND MANUFACTURE OF IRON OR STEEL AS ARMOUR FOR SHIPS OR BATTERIES
Year: 1861

page_text: LETTERS PATENT to George Clark, of -No. 30, Craven Street, Strand,
London, for the Invention of "IMPROVEMENTS IN THE USE, APPLICATION,
AND MANUFACTURE OF IRON OR STEEL AS ARMOUR FOR SHIPS OR BATTERIES."
Sealed the 30th May 1862, and dated the 7th December 1861..
PROVISIONAL SPECIFICATION left by the said George Clark at the Office
of the Commissioners of Patents, with his Petition, on the 7th December
1861.
I, GEORGE CLARK, of No. 30, Craven Street, Strand, London, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN THE USE,
APPLICATION, AND MANUFACTURE OF IRON OR STEEL. AS ARMOUR FOR SHIPS OR
BATTERIES," to be as follows:-
This Invention consists in improved modes of manufacturing, fastening, and
backing iron or steel armour. plates. To render the description of the
improvements comprised in the Invention more clear and intelligible, they are
classed under the following heads :-
1. The form of armour plates.
2. The nature of the backing to armour plates..
3. The mode of attaching and fastening armour plates and backing.
4. The structure forming the back support or foundation_to.armour-plates-
-and-their backing.
1st. In the form of iron armour plate I propose three improvements, of which
one is shown in Fig. 1, one in Fig. 2, and another in- Fig. 3 of the Diagrams

page_text: 1
hereunto annexed. The first consists in manufacturing armour plates with
ribs running longitudinally on the under side thereof, for the double purpose
of adding to the strength of the plate without too great an increase of weight,
and of rendering the ribs available for attaching the fastenings of the plates
thereto, without perforating or diminishing the thickness or substance of the
body of the plate. In manufacturing iron plates to be used as armour, one,
two, or more ribs are to be forged or rolled on one side as part of the plate.
The dimensions of the ribs, and their distance from each other may be varied
according to circumstances, and will depend upon the dimensions of the plates.
Fig. 1 sufficiently indicates the nature of this improvement.
The second improvement under this head consists of the addition of bosses
or projections to the plates in forging or rolling the same, as shown in Fig. 2.
These bosses or projections may be added to the under or upper side of the
plate, and are intended to compensate the diminuition of strength of the plates
at those parts where the iron is perforated in order to attach the fastenings
which hold the plates.
The third improvement, as shown in Fig. 3, consists in giving to the
armour plate a convex surface on the upper side and a'concave or flat surface
on the under side, the object of this improvement being to diminish the effect
of projectiles on a plate by causing the latter to receive the impact obliquely.
In the application of these three improvements the size of the plates will have to
be governed by circumstances; but the dimensions I prefer are 6 to 10 feet in
length by 8 to 12 inches in width, because plates of those dimensions may be
more easily and perfectly manufactured, and more readily and securely fastened
than larger plates with considerable economy of expense and time.
2nd. In the backing to armour plates, my improvements consist of three
modes illustrated in Diagrams, Fig. 4, 5, & 6. The first is a system of
wrought or cast iron or steel tubes placed end on between the armour plates
and the ship's skin or planking, and which, for distinction, I call the tubular
backing. The tubes, which may be circular, square, or pentagonal, are calcu
lated to resist the shock of projectiles on the plates to which they serve as
backing, on the principle of tubular columns in architecture, or the bones of
animals, as the most perfect form combining strength-with-economy_and
lightness of material. The tubes should be of the same length varying from
4 to 12 inches, but in that respect there is no arbitrary rule. Each case will
regulate the required length. As to the diameter of the tubes and the thick-
ness of iron, the former may be varied from 3 to 6 inches and the latter from
to 1 inch, but I recommend 5 inches external diameter and an inch
thickness of metal as most suitable. The mode which I propose for adapting

page_text: these tubes as a backing to armour plates, is, first, to attach to the outside of
the skin of an iron or the planking of a wood ship a backing or foundation
plate to inch thick, then to lay the tubes horizontally with one end
against this plate in courses supported by frames of hard wood or other
material, as shown in Fig. 4, or they may be supported by iron framing or
reeved on to bevelled tongues, or placed one on the other after the manner of
cells in a honey comb. When the tubes are thus placed, presenting an even
surface outside, I propose fixing over them another iron plate to an inch
in thickness, with or without ribs running between the courses of tubes.
This outer plate may be fastened by screw bolts or rivets to the skin or timbers
of an iron ship or by wood screws to the planks of a wood ship, and will,
when thus fastened, hold the tubes securely in their places. The combined
structure will form the backing to the armour plates, of which the fastenings,
whatever their nature may be, will pass through some of the tubes, and
through holes perforated in the two iron plates, and this fastening will draw
the backing as well as the armour plates tight to their bearing.
Fig. 5 represents the second improvement under this head, consisting of
angular plates of iron or T-iron placed between two iron plates, and fastened
outside the skin of an iron ship, or on the planking of a wood ship with
or without wood filling, as shown in Fig. 5.
Fig. 6 represents the third improvement under this head, consisting of two
iron plates manufactured after the manner of T- iron (with one, two, or more
projecting plates all of the same depth and with T-heads) attached at right
angles to the former, such projecting plates being at suitable distances from
each other, so that when the two plates so manufactured are placed one over
the other with the projecting plates between them, the T-heads of the latter
will rest upon the inner side of the opposite plate, respectively forming longi-
tudinal cells a few inches in width between the projecting plates. To insure
close contact of the parts, and prevent vibration, a packing of hard bituminated
felt or other suitable material will be placed under the T-heads of the pro-
jecting plates; the cells may be with or without wood or other filling. The
mode of fastening will be the same as described under Fig. 4. In the appli-
cation of either of these modes of backing, the armour plate will be fixed
upon the outer covering plate.
3. With reference to the mode of attaching and fastening armour, plates
and.backing, the following improvements form part of my Invention :-In my
Invention for "An Improved Method of Connecting & Fastening together
Blocks, Plates, or Slabs of Wood, Metal, or any other Material," for which I
obtained Her Majesty's Letters Patent, No. 482, dated the 25th day of

page_text: 4
February last, I described the mode of forming dovetailed slots on the inner
side of armour plates, and attaching fastenings to them by means of bevelled
tongues fitting into the slots. I now propose to carry out the same principle
of fastening by forming bolts with dovetailed heads, as shown in Fig. 7, and
attaching these bolts to the armour plate or backing by inserting the bevelled
or dovetailed head of the bolt into a dovetailed slot formed on the plate or
backing. The dovetailed head of the bolt will thus perform the office of a
bevelled tongue, and may be continuous, forming the head to two or more
bolts..
In the Diagrams, Fig. 7 (a) is the bolt; (6) the bolt head bevelled; (c) a
sectional line through the centre of the bolt; (d) section of the bolt and
dovetailed head at (c); (e) end view of the bevelled head.
4. The following is a description of the improvement in the structure of the
foundation or back support for armour plates adapted to an iron ship, but it
is applicable, with modifications, to a wood ship or a battery:-Between the
timbers of the ship I fasten two angular plates up and down of the same
depth as the timbers, as shown in Fig. 8, one side of the angle of each plate
abutting against the ship's skin plates, the two covering the space between the
angle irons of the timbers, and the other side of the angle of each plate
abutting one against the other at right angles to the ship's skin in the centre
between the timbers. In this arrangement the ordinary caulking plates are
omitted, and these angular plates are rivetted to the ship's skin plates at the
seams of the latter, whereby the seams are securely caulked, and the angular
plates are fastened to the ship. Or I effect the same object on the same plan
by means of a T-plate (Fig. 9) all in one, covering the ship's skin plates
between the angle irons of the timbers. In either case the inner ends of the
angular plates or of the T-plate are turned right & left to form a T-head
inside, over which a plate is fastened over all between and to the timbers ends
with rivets or screw bolts forming an inner skin to the ship; the space
between the two skins may be filled up solid with wood. This arrangement
will form part of the structure of the ship, add greatly to its strength, & be
an effective back support to resist the crushing-effect on the ship's structure of
projectiles striking the outer plates.
In cases where rivet heads on the ends of plates overlapping each other
cause inequality of any surface over which I wish to place any of the foun-
dation plates or angular plates before-mentioned, I propose to obtain an
éven & smooth surface for such plates by filling the spaces between the pro-
jecting parts with Roman or Portland cement, or other similar cement which
will harden like stone.

page_text: Under the 2nd head of my improvements, referring to the backing to armour
plates I have to add another method, of which here is a Diagram,
which is a transverse section of a long iron trough without ends;
these troughs I propose shall be placed side by side longitudinally,
U
and fastened together laterally by rivets, as thus represented, and I intend
to apply the same method of lateral rivet fastenings
to all the other modes of cellular iron backing,
herein-before described, in all cases when it is
practicable. And as a further improvement in the
mode of fastening armour plates on the plan of my Invention of "An
Improved Method of Connecting and Fastening together Blocks, Plates,
or Slabs of Wood, Metal, or any other Material," for which I obtained
Her Majesty's Letters Patent, No. 482, dated the 25th February, 1861
propose securing the bevelled tongues therein described to the structure
of the ship by rivetting the bolts which hold the tongues either to the
skin or timbers of the ship, or to a bearing plate inside the skin of the
ship.
I
The following is a descriptive reference to the Diagrams of the different
heads under which I have described my Invention, showing the parts of each
of the improvements indicated by the letters on the Drawings, Fig. 1, 2, 3, 4;.
5, 6, 8, and 9, those of Fig. 7 being already herein-before described. Fig. 1
(a) is the body of the plate; (b) represents the longitudinal ribs, of which two,
are shown on the upper and one on the under Drawing, the dotted line
showing the direction of the tongue. Fig. 2, (a) is the body of the plate;
(b) the boss or projection; (c) the bevelled slot. Fig. 3, (a). is one form;,
(b) another form of plate with convex surface. Fig 4, (a) is an iron-cylinder;
(b) the interior of the cylinder, which may be left hollow or filled in with
wood or any o
.other substance; (c) represents a wood frame to carry the
cylinders. Fig. 5 (a) is the foundation plate; (b) L-iron forming cells, and,
(c) the top or, bearing plate on which the armour plates will rest. Fig. 6
(a) is the foundation plate; and (6) the top bearing plate with projecting
plates (c, c,) at right angles to the plates (a, b,) attached to them; (d, d,)
are T-heads, and (e) represents the felt or other-packing on which the T-heads
rest. Fig. 8 and 9 (a, a,) are the sides of the angular plates which are to
be rivetted to the skin of a ship; (b) are the projecting parts of the plates at
right angles to the former, forming ribs; and (c, c,) show-the-T-heads at the
inner_extremity-of-the-former.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said George Clark in the Great Seal Patent Office on the 7th
June 1862.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
CLARK, of No. 30, Craven Street, Strand, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventh day of December, in the year of our
Lord One thousand eight hundred and sixty-one, in the twenty-fifth year
of Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said George Clark, Her special licence that I, the said George
Clark, my executors, administrators, and assigns, or such others as I, the
said George Clark, my executors, administrators, 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 USE, APPLICATION, AND MANUFACTURE OF IRON OR STEEL AS ARMOUR FOR
SHIPS OR BATTERIES," upon the condition (amongst others) that I, the said
George Clark, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, 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 George Clark, 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 follow-
ing statement:-
•
This Invention consists in improved modes of manufacturing, constructing,
and fitting iron or steel armour plates, and their backing, fastenings, and
-fittings. To render the description of the improvements comprised in the
Invention more clear and intelligible as they-consist_of_many_parts, they are
classed under the following heads :-
1. The form of armour plates.
2. The nature of the backing to armour plates.
3. The mode of attaching and fastening armour plates, and the backing
thereof.

page_text: 4. The structure forming the back support or foundation to armour plates,
and the backing thereof.
.
1st. In the form of armour plates I propose improvements, of which one
is shown in Fig. 1, one in Fig. 2, and another in Fig. 3 of the Diagrams
hereunto annexed. The first consists in manufacturing armour plates with
ribs running longitudinally on the back or inner side thereof, for the double
purpose of adding to the strength of the plate, without too great an increase of
weight, and of rendering the ribs available for attaching the fastenings of the
plates thereto.without perforating or diminishing the thickness or substance
of the body of the plate. In manufacturing these plates one, two, or more ribs
are to be forged on one side, and as part of the plate. These ribs may be
formed in the process of manufacturing the plates by hammering in the usual
way to a pattern, or by passing the plates through rollers with grooves cut to
the pattern.. The dimensions of the ribs and their distance from each other
may be varied according to circumstances, and will depend upon the dimensions
of the plates, but as a rule I propose that the ribs should be from 3 to 6 inches
wide, and 2 to 3 inches deep, and that the spaces between the ribs should be
the same as the width of the ribs; Fig. 1 sufficiently indicates the nature of
this improvement.
The second improvement under this head consists in the addition to the
plates of transverse bosses, projections, or ribs in forging or rolling the same
in the forms shown in Fig. 2, or other similar forms: These bosses, projec-
tions, or ribs may be added to the under or upper side of the plate, and are
intended to compensate the diminution of strength of the plates at those parts
where the iron is perforated or penetrated in any way for the purpose of attaching
the fastenings which.hold the plates.
The third improvement, as shown in Figure 3, consists in giving to armour
plates a convex surface on the upper or outer side; and a concave or flat sur-
face on the..under or inner side, the, object of this improvement being to
diminish the effect of projectiles on a plate by causing the latter to receive the
impact obliquely. In the application of these three improvements; the size of
the plates will have to be governed by circumstances, but the dimensions I
prefer are 6 to 10 feet in length, by 8 to 12 inches in width, or not exceeding
20 to:24 inches in width, because plates of those dimensions may be more easily
and perfectly manufactured, and more readily and securely fastened with
economy of expense and time than larger plates; but it may be desirable to
make use. of plates of larger dimensions and all the improvements under this
head are applicable whatever may be the size of the plates.
2nd. In the backing to armour plates, my-improvements consist of several

page_text: modes illustrated in Diagrams, Figs. 4, 5, 6. The nrst, Fig. 4, is a system of
wrought or cast iron or steel tubes placed end on between the armour plates, and
the ship's skin or planking, and which for distinction I call the tubular backing.
The tubes which may be circular, oval, square, or pentagonal are calculated to
resist the shock of projectiles on the plates to which they serve.as backing,.on
the principle of tubular columns in architecture or the bones of animals, as the
most perfect form combining strength with economy and lightness of material.
The tubes for any one series or compartment of backing should be of the same
length, varying from 4 to 12 inches, but in that respect there is no arbitrary
rule. Each case will regulate the required length. If to correspond with
any irregularity in the structure of the framework of a ship or battery the
tubes are required to be of different lengths, the lengths must be so re-
gulated that the outer surface presented by the ends of the tubes shall be a
true level all over, and form a level bed for the armour plates. As to the
diameter of the tubes, and the thickness of iron, the former may be varied
from 3 to 6 inches or more, and the latter from of an inch to one inch; but
I recommend 5 inches external diameter, and an inch thickness of metal
as the most suitable dimensions. The mode which I propose for adapting
these tubes as a backing to armour plates is first to attach to the outside of
the skin of an iron, or the planking of a wooden ship, a backing or foundation
iron plate to inch thick, secured to such skin or planking with rivets or
screws, then to lay the tubes horizontally with one end against this plate in
.courses supported by frames of hard wood, or other suitable material, as shown
in Fig. 4, or they may be supported by iron framing or reeved on to bevelled
tongues fixed to the foundation plate or placed one on the other after the
manner of cells in a honeycomb, or they may be revetted together by means
of rivets passed through the sides of the tubes. When the tubes are thus
-placed and secured presenting an even surface outside, I propose covering that
surface with packing of a thin sheet of asphalted felt, or cardboard, or other
material of the nature, and in the manner herein-after described 1 to 1 inch
thick, and then over this packing I propose fixing an iron plate to an inch
_in_thickness_with_or_without_ribs_to_the_plate_running_between_the_courses of
tubes. This outer plate, which I call the covering plate as well as the foun-
dation plate may be fastened by screw bolts, or rivets to the skin or frames
of an iron ship, or by wood screws or bolts to the planks or timbers of a
wood ship, and will when thus fastened hold the tubes securely in their places.
The combined structure will form the backing to the armour plates, of which
the fastenings, whatever their nature may.be, may pass through some of the
tubes, and through holes perforated in the foundation, and covering plates

page_text: and this fastening will draw the backing as well as the armour plates tight to
their bearing. Figures 5 represent the other improvements under this head,
which I term cellular backing, consisting of angular shaped plates of iron
or T, or angle iron bars of various forms fixed between a foundation. and
covering plate, so as to form narrow longitudinal cells, and fastened outside the
skin of an iron ship, or the planking of a wood ship in the manner described
for the tubular backing; Figure 6 represents particular forms of angle plates
which I propose to make use of for constructing longitudinal iron cells. These
plates will be manufactured after the manner of T-iron, with one, two or more
projecting plates (all of the same depth, and thickness) at right angles to the
former plates, such projecting plates being at suitable distances from each other
so that when the two plates so manufactured are placed one over the other
with the projecting plates between, them, the ends of the latter will rest upon
the inner side of the opposite plate respectively, forming longitudinal cells
a few inches in width between the projecting plates. To insure close contact
of the parts and prevent vibration, a packing of hard bituminated felt or card-
board, or other suitable material will be placed under the ends of the projecting
plates which will rest thereon.
• Another method by which I propose to construct iron cellular backing is
illustrated by Diagram .Fig. 5 (c), which represents a. transverse section of an
iron trough; these troughs I propose shall be placed side by side longitudinally
and fastened together by rivets laterally, as represented in the Diagrams, and
also by rivets to the foundation and skin plates, or either of them, and I intend.
to apply the same method of lateral rivet fastenings, and riveting to the skin
of the ship to all the other modes of cellular iron backing, as well as the;
tubular backing herein-before described in all cases where it is practicable..
The angle bars or plates of any of the forms herein-before described, or of any
other forms which may be devised, are intended by me to form narrow cells, which,
when arranged and fixed as herein described and illustrated by the Diagrams;
will be iron girders, which as well as the tubular cells being placed between
the skin or planking of a ship and the armour plates, will strengthen the ship.
and support the armour plates, and better enable them to resist projectiles.
To effect these objects in the most effectual way I consider and I
propose that
the dimensions of the cells should be 6 to 8 inches in depth, and 5 to 6 inches;
in width, and the thickness of iron forming the walls of the cells from a half.
inch_to_one.inch: The-rule-by-which-the-width-of-the-cells should be governed
is the diameter of the projectiles to be resisted; and as it is known from expe-
riments that the projectiles which have sufficient force to penetrate or crush,
through iron plates of the thickness used for naval armour is 8-to 10 inches,

page_text: it follows that the cells should be 5 to 6 inches in width, or about one-third
less than the diameter of the shot, the object to be held in view for the suc-
cessful application of my tubular or cellular system of backing being that the
width of the cells shall always be somewhat less than the diameter of the
projectiles to be resisted. The longitudinal cells or girders may be fixed on
the ship horizontally or vertically, but I prefer the former arrangement. It
will add greatly to the strength of the vessel by bracing her fore and aft with
horizontal frames, so that she will have a double skin, and a double framing
with all the parts securely fastened to each other with rivets and bolts, and
incorporated in the structure of the ship. The mode of fixing and fastening
for all these modes of constructing longitudinal cells will be the same as
described under Figs. 4 & 5. In the application of either of these modes of
backing the armour plates will be fixed upon the outer covering plate, or on
the top of the cells if there be no covering plate, which when the cells are
filled with wood or other material may be found unnecessary; and in all
cases I intend to place a thin sheet of bitumenated felt, cardboard, or gutta
percha, or any other hard and compressible material, but not elastic, or as
little so as possible between the surface of plates to prevent jar or vibration.
Although I have described various modes of constructing and arranging
the cellular backing, I do not confine myself to those modes; they all form
parts of my Invention, which under this head consists of the arrangement of
narrow cells formed of iron or steel placed edgeways in the manner herein
described for the purpose of forming a backing to armour plates, and contri-
buting to the strength and protection of the ship. In some cases I intend
that the cells shall be filled with wood, or some other dense and rigid substance,
of which the weight shall not be too great. I propose that the wood shall be
placed with the grain on end as it is calculated when. so placed to offer greater
resistance to the force of projectiles, but it may also be placed with the
fibre running horizontally. I also propose to fix the blocks or beams of wood
to be used as filling to the cells with bitumen, glue, or cement, in order to fill
up interstices, and thereby more effectively consolidate the mass, and pre-
-vent-vibration. I give the preference for that purpose to pitch or asphalt
applied hot as the wood is inserted in the cells, and in some cases I recommend
that the wood used as filling, should be compressed and prepared with sulphate
of copper, or some other process to preserve it from decay.
3rd. With reference to the mode of attaching and fastening armour plates
and backing, the following improvements form part of my Invention:-In
my Invention for "An Improved Method of Connecting and Fastening together
Blocks, Plates, or Slabs of Wood, Metal, or any other Material," for which I

page_text: obtained Her Majesty's Letters Patent, No. 482, dated the 25th day of February
1861, I described the mode of forming dovetail slots on the inner side of armour
plates, and attaching fastenings to them by means of bevelled or dovetailed
tongues fitting into the slots. I now propose to carry out the same principle
of fastening by forming bolts with dovetailed heads, as shown in Figs. 10, and
attaching these bolts to armour plates or their backing by inserting the bevelled
or dovetailed bead of the bolt into a dovetailed slot formed on the plate or
backing. The dovetailed head of the bolt will thus perform the office of a
bevelled tongue, and may be the head of one bolt only; or continuous, and
forming the head to two or more bolts. This form of a dovetailed-headed bolt
to be inserted into a dovetailed slot, may be considered in principle, and in fact.
as part of my said Invention patented the 25th February 1861, No. 482, for
the bevelled tongue therein described is a continuous bolt head, but in order to
leave no doubt on that point, I describe the dovetail-headed bolt as a part of
my present Invention. In the Diagrams hereunto annexed this arrangement
is illustrated by Figs. 10.
As a second improvement.in the mode of fastening armour plates on the
plan of my Invention of "An Improved Method of Connecting and Fastening
together Blocks, Plates, or Slabs of Wood, Metal, or any other Material," for
which I obtained Her Majesty's Letters Patent, No. 482, dated the 25th
day of February 1861, I propose securing the bevelled tongues therein described
to the structure of the ship by rivetting the bolts which hold the tongues either
to the skin or frame of an iron ship, or to an iron plate fixed inside the skin
of an iron ship, or upon or between the timbers of a wooden ship.
As a third improvement on my aforesaid patented Invention, dated
February 25th, 1861, No. 482, I propose in some cases to make use of an
iron plate of which the edges of two parallel sides being bevelled shall fit and
slide into recesses with bevelled edges.rolled or cut into the back of an iron
armour plate, and serve as a backing and as a fastening to such armour plate.
This improvement is illustrated by Diagram Fig. 7, and is herein-after more
particularly described in the note at the end of this Specification referring to
the Diagrams. This plan I consider to be more particularly applicable to the
planks of wooden ships, because the bevelled backing plates can be readily
fastened to the planks, and the armour plates would be securely held by this
method. But I believe it will be found advantageous for land batteries
which-are-proposed-to-be-covered-with-heavy iron plates. For that purpose I
recommend that the armour plates should be fixed vertically and of the
following dimensions, namely, in length 6 feet, in width 18 to 20 inches, and in
thickness 6 inches, for a width of 12 to 14 inches in the centre and 9 inches for a

page_text: width of 3 to 4 inches at each side, the outer thicknesses forming ribs bevelled
inside to receive the bevelled-edged backing and fastening tongue plate. This
method of applying my bevelled tongue-fastening will admit of large bolts 2
to 3 inches in diameter to be used to fasten the tongue plate inside the
structure of the battery, to which it would impart great strength and solidity.
The fixing of the armour plates can be effected with great simplicity and ease,
and they can be readily removed and replaced; and if found to be advan-
tageous or desirable the tongue plate may be of sufficient length to admit of
two or more armour plates being fixed upon it. Although I have described
this method of fastening with bevelled tongue plates fixed vertically, it is
evident they may be, if considered advantageous or useful, be fixed
horizontally.
A fourth improvement in connexion with my before-mentioned Patent of
the 25th February 1861, No. 482, is the mode of scarfing the bevilled tongues
which form part of that, Invention in the manner shown in Diagram, Fig. 14,
and referred to in the descriptive note of the Diagrams herein-after contained.
The object of this improvement is to facilitate the removal of á plate or series
of plates by drawing it or them out along with a portion of the tongue and
bolts attached without the necessity of removing the plates above, which aro
fastened on the same series of tongues.
4th. The following is a description of the improvement in the structure of
the foundation or back support for armour plates adapted to an iron ship, but it
is applicable, with modifications, to a wooden ship or a land battery or fort:-
Between the frames of an iron ship I fasten two angular plates up and down of
the same depth as the frames or nearly so, as shown in Fig. 8. One side of
the angle of each plate abuts against the ship's skin.plates; and these two sides
cover the space between the angle irons of the frames, and the other sides of
the angle of the angular plates abut one against the other at right angles to
the ship's skin between the frames. In this arrangement the ordinary caulking
plates may be omitted and these angular plates be rivetted to the ship's skin
plates at the seams of the latter, whereby the seams will be securely caulked
and the angular-plates_be_fastened to the ship; or the two angular plates
instead of abutting one against the other, back to back, may be an inch or two
apart, leaving a space between them for the passage of the bolt fastenings of
the armour plates or backing. I effect the same object on the same plan by
means of a T-plate, Fig. 8b, all in one, of the same form and dimensions as the
two angular plates covering the ship's skin plates between the angle irons of
the frames. In either case the inner ends of the angular plates or of the
T-plates may be turned right and left to form a T-head inside, over which a
:

page_text: plate may be fastened over all between and to the frame ends with rivets or
screw bolts forming an inner skin to the ship. The space between the two
skins may be filled up solid with wood. This arrangement will form part of
the structure of the ship, add greatly to its strength, and be an effective back
support to resist the crushing effect on the ship's structure of projectiles
striking the outer plates.
In some of the foregoing descriptions of some parts of iny Invention I have
mentioned the use and application of a packing composed of bitumenated felt,
cardboard, gutta perchà, or other hard and yielding material. I consider this
arrangement as part of my Invention, and I propose its application in all cases
when practicable between iron surfaces which require to be closely pressed and
held against each other, and I look upon this arrangement as a means of
preventing vibration as of great importance, vibration in naval armour from
impact of projectiles being in my opinion one of the chief causes of fracture of
armour plates and their fastenings, I wish to be clearly understood in the
distinction between the kind of packing I have described and an elastic bed or
medium between iron surfaces, for I believe that elasticity in the separate parts
of the structure, so that they can easily separate themselves from each other, is
calculated to cause fracture; but an elastic bed at the back of and extending
unbroken over the whole surface of a structure of sufficient strength to resist
the crushing effect of projectiles may be used with advantage for the purposé
of absorbing the force of the blow, and to effect that object I propose to
introduce a bed of india-rubber or other elastic material over the entire
surface of the skin of an iron ship or the planks of a wooden ship under the
foundation plates of my systein of tubular or cellular backing. I propose that
this elastic bed shall be from a quarter of an inch to an inch or more in
thickness, but the precise degree of thickness will depend upon and must vary
with circumstances which experience will determine. I wish it however to
be understood that this elastic medium will in my opinion be detrimental unless
the structure of armour plates and backing bedded upon it is of sufficient
strength and rigidity to resist the crushing' effect of projectiles, and unless the
elastic bed bé so arranged that it shall serve as a continuous buffer to the
entire back surface of the said structure. In cases where rivet heads or the
ends of plates overlapping each other cause irregularity of any surface over
which I wish to place any of the foundation covering or angular plates-before-
mentioned, I'propose to obtain an even and smooth surface and bed for such
plates to bear upon by filling in the space between any projecting parts with
Roman or. Portland cement or other similar cement which will harden
like stone.

page_text: The following is a descriptive reference to the Diagrams of the different
improvements which I have described as parts of my said Invention, or
relating thereto, showing the parts of each of the improvements so described
or referred to by the letters on the Drawings.
Figs. 1, transverse sections of iron plates with one, two, or three longitu-
dinal ribs rolled or hammered in manufacturing the plates. (a), the body of
the plate; (b), the ribs. Figs. 2, longitudinal transverse sections of an iron
plate with ribs across one side thereof, formed in manufacturing the plate or
welded thereon; (a), body of the plates; (b, b), ribs; (c), dovetailed or
bevelled slot cut in the rib; (d), boss or convex rib, or the under side of plate
with slot therein; (e), boss or convex rib on the upper side of plate above
slot (f) Figs. 3, sections of conv explates showing (a), a plate, convex on the
upper and concave on the under side; (b), another plate, convex on the upper
and level on the under side; (c), angulated plate, convex at the angle, being
intended to be used as the top armour plate, for the purpose of more
effectually resisting the effect of projectiles striking the top of an upper plate on
a ship's side or battery, by causing the projectile to glance off the plate. Figs. 4,
iron tubes to be used for backing, in the manner herein-before described; (a)
is the iron tube; (b), the interior of the tube, which may be plugged with
wood or filled with cement or any other material, as may by experience be
found serviceable; (c), a wooden frame supporting the tubes; (d, d), oval
tubes with rivets fastening them together. Figs. 5, single and double angle
irons forming longitudinal cells, as shown by the sections; (a), an ordinary
angle iron bar; (6) shows the formation of cells, by rivetting angle bars back
to back and to the plate (e), which may be the skin plate of a ship or a back-
ing plate; (c) is a double angle bar or box girder; (d, d), shows the formation
of longitudinal cells, by rivetting the iron boxes or troughs to each other and
to the skin or backing plate (e) with rivets (f). Fig. 6 represents the mode
of forming longitudinal cells herein-before described and referred to under
Fig. 6 (a), the foundation plate; (b), the top or covering plate; (c), the
angle plates; (d), felt or other yielding packing to receive the ends of the
angle plates (c); (e), rivet fastenings to secure the foundation plates to
the skin or backing plate; (f), bolt to fasten the top or covering plate and
draw it down to its bearings on the under plate. The plates thus arranged
form longitudinal cells, of which the number may be increased by adding to
the width of the foundation and covering plates and the number of angle
plates, or by rivetting series of these angulated plates side to side. The
dimensions I consider most appropriate for the construction of this system of
iron cells are an inch to one inch thickness of iron, width of the cells 5 to

page_text: 6 inches, and depth thereof 6 to 10 inches; the angle irons must be equi-
distant. Figs. 7 represent a bevelled or dovetailed backing plate, serving at
the same time as a tongue, on the system of my Invention patented the 25th
day of February 1861, No. 482, and applied to an armour plate. (a) is thé
armour plate; (b, 6), ribs at each end of armour plate bevelled to correspond
with the bevel of the tongue plate (c); (d) is a wedging plate; (e), a founda-
tion plate resting on the skin plate (f), or on the planking of a ship or
backing (g); (h,i,j), are rivet and bolt fastenings connecting and holding the
whole system together. The mode of proceeding to form this structure is, first,
to fasten the foundation. plate (e) to the skin plate (f), or the wood plank or
timber (g), then to fix in its place the tongue plate (c), which should be to
an inch less in depth than the slot in the armour plate between the ribs (b, b):
The tongue plate being fastened with rivets or bolts, the armour plate is
reeved over it and keyed up with wedge plates at (d and k).. Figs. 8 represent
back support plates to be fixed inside the skin of an iron ship, as herein-before
described. (a), the section of a single plate; (b, b), two plates rivetted
together and to the skin plate with a space of 1 or 2 inches between them to
allow for the passage of the bolt fastening to the armour plate. Figs. 9 repré-
sent another kind of back support to the skin and frames of a ship placed
between the frames, as shown in this Diagram. (a), the skin plate; (b; b);
ship's frames; (c, c,) rib plates, each being half of an arch and two when fixed
in their places, as here shown, forming an arch of which the key is formed by
the angular pieces (d, d.) being rivetted or screw-bolted together, and the abut-
ments are formed by the ends of the ribs (e) being fastened together and to
the ship's frame by rivets (f), or screw bolts. passing through the whole. By
this arrangement, one arch abuts upon the other from frame to frame, and
adds to the strength of the ship and the power of resistance of the structure to
the shock of projectiles on the armour plates. I propose that the dimensions
of these should be 2 inches in width and 3 inches in depth, and that they
be fixed between the frames at distances of from 9 to 12 inches from each
other. Fig. 10 is my system of bolts with bevelled bar heads; (a)-represents
a longitudinal view of a single bolt with its bar head (b); (c), a transverse
section through the dotted line at (a); (d), an end view of the bevelled bar
head (b); (e and f) represent three bolts attached to one bevelled bar head,
of which the transverse section and end view will be the same as (c and d):
Fig. 11 represents a mode of fastening bevelled or dovetailed tongues to the
side of an iron or wooden ship, with rivets, bolts, or screws; (a), the bevelled
_tongue, on-to-which-the-armour-plate-is-intended to be reeved; (b), a neck to
the tongue; (c, c), flanges connecting the neck to the tongue, the whole-form."

page_text: ing a T-shaped bar with a dovetailed tongue at its extremity. The flange
plates (c, c,) are fastened to the skin (d) or the planks (e) with rivets, bolts,
or screws (f, g, h). Fig. 12 represents my improvement of yielding or elastic
wedge plates for keying or wedging up armour plates to their bearings and
backings; (a) is a plate of iron rolled or planed very true, of the uniform
thickness of to an inch or more; (b, b,) are coatings of asphalted felt,
cardboard, gutta percha, or vulcanized india-rubber, fixed to each side of the
plate by being laid on hot and afterwards rolled smooth and true; (c, c); thin
plates of iron or steel, or other metal, to of an inch in thickness, of which
the external surfaces are planed very smooth and true, and fixed together by
the adhesion of bitumenized felt or other yielding or compressible material, of
which a thickness of to of an inch is to be inserted between the metal
plates; so that the combined plate will present smooth metalic surfaces out-
side, and having a yielding material between the plates, will be compressible
in wedging up. Figs. 13 represent an iron. tube intended to be used as a
sheath, fixed in wood, through which it is proposed to pass a red-hot rivet or
bolt; so as to protect the wood from being ignited or burnt by such red hot
rivet or bolt in its passage through the wood. The sheath is to be of a dia-
meter to allow of the easy passage of the rivet or bolt, and of any length
required for the protection of the wood, and it may be in two pieces. (a), the
shaft of the tube; (b, b), conical ends when required; (c), the inside of the
tube. Figs. 14 represent a bevelled tongue scarfed. (a), a portion of
the tongue, of the same length as the width of a plate or séries of plates pro-
posed to be removable by unscrewing the bolts (c) and thereby separating the
part (a) of the tongue from the parts (b, b): Figs. 15 represent an improved
kind of nut, which may be wedged after the bolt is screwed up; (a), the nut;
(6), projecting ends to nut to carry wedge plate; (c), the bolt; (d), the skin
plate to which the nut is heaved up; (e), the wedge plate or key to be driven
in behind the nut across the bolt. Figs. 16 represent a rivetting collar for bolt
ends; (a), the collar with a conical opening at the outer end; (b); bolt shaft;
(c), bolt end protruding from collar; (d) bolt end rivetted into the conical
opening of the collar: This is a plan for converting the point of a screw bolt
into a rivet end:-
In applying this method of rivetting, the series of bolts to a plate would be
first heaved up tight by means of nuts 4 or 5 inches in length, tapped only
2 inches at the outer end, and the thread at the point of the bolt cut only to
the same extent. :

page_text: either cold or.red hot, and shrunk; and then the end of the bolt is to be made
red hot and rivetted into the conical opening, of the collar.
Fig. 17 is a horizontal section of armour, plating applied to an iron ship;
showing horizontal cellular backing outside, and arched supporting ribs inside
the skin plate of a ship on the plan of my Invention, herein-before' described...
(a), armour plate; (b); tongue plate; (c, c), bolt fastenings, of which one is
rivetted, and the other screwed up with a nut; (d), wall of a longitudinal cell
of my cellular. backing, placed horizontally outside the skin plate of a ship;
(6), rivets, fastening the walls of the longitudinal cells together; (f), rivets
fastening the bottoms of the cells. to the skin plate; (g), arched rib sup-
ports inside the skin. plate. Fig. 18 horizontal section of armour plating.
applied to an iron ship, showing longitudinal cellular backing, formed of.angle
irons placed. vertically outside the skin of a ship, with back supporting plates
between frames of ship. (a, a), armour plates; (b, 6), bolt fastenings ; (c; c);
5: walls of longitudinal cellular backing;. (d, d), longitudinal cells, which may
be filled with wood, or other material; (e, e), back supporting plates.inside
skin; (f), inner skin or transverse bars, fastened over the .ends. of ships'
frames. Fig. 19, horizontal section, showing back support of.angulated plates
inside the ship's skin between the: frames, and showing also transverse; bars for
wedging up the back support. (a, a), armour plate; (b, b), transverse ribs of
armour plate, into which the dovetail slots are cut; (c; c), cellular backing.
outside: skin. plate, placed horizontally; (d, d), rivets fastening cell plates
together; (e, e), ship's skin; (ff), angulated' iron support inside the ship's
skin, to which, and to the bottom of the longitudinal cells it is fastened with
5: rivets; (9); inner iron. skin plate, bearing on the ends of the angulated iron
supporting plates, and fastened to the ship's frames; "(h), wood filling between.
ship's skin plate. (e) and the inner skin plate. (g); (i),.transverse bar, with
flanges rivetted or: bolted to the ship's frames... The purpose of bars of this
description is to act as bearings, against. which: to wedge up the wood 'filling
and the inner:skin plate by driving in wedges between the bars and the inner
skin. plate. Fig. 20, vertical section of armour plating, showing horizontal
cellular backing. formed of box.girders, and showing also a convex angulated
top armour plate.. (a,,a), armour: plates; (b), convex angle of armour.plate;
(cc),ribs, in which the dovetailed slots are cut; (d; d), box girders; forming
the longitudinal, cells; (e, e), inverted box girder, inside a longitudinal cell:
for the better support of the joint of two armour plates.
I intend that all. the improvements.described in this Specification as appli-
cable to iron ships shall, in all cases when practicable, be made.applicable-to-the
armour plating of wooden ships, batteries; forts; or other structures used as

page_text: defences against projectiles. In all cases where iron plates or bars are men-
tioned or referred to I mean to make use of steel plates or bars when
practicable and it may be desired to do so.
Having described the nature of my said Invention, and manner of
carrying the same into effect, I wish it to be understood I do not bind
myself to the precise details herein-before contained, as the same may be
varied without differing from the principles of the Invention; but what I claim
and desire to have secured to me by Her Majesty's Letters Patent isş, the
following improvements, namely:-
1. The form of armour plates, under which head I claim the improvements
or modifications in the forms of armour plates intended to be applied with
dovetailed slots cut or otherwise formed in or upon them on the plan of my
Invention, for which a Patent was granted to me dated the 25th February
1861, No. 482, according as such improvements or modifications are herein
described and shown in the Diagrams..
2. The nature of the backing to armour plates, under which head I claim
the application and formation of tubular or longitudinal cells constructed and
fastened outside the iron skin, or the wooden planking of a ship or battery, or
outside any other structure to be used as a defence against projectiles, such
'cells being formed and arranged and fastened to the ship, battery, or other
structure in any of the manners herein described and shown in the Diagrams
or otherwise, and placed between the outer surface of any such, ship, battery,
or structure and the armour.plates.
3. The mode of attaching and fastening armour plates and the backing
thereof, under which head I claim the improvements or modifications in the
mode of fastening described in my before-mentioned Invention, for which L
obtained a Patent, dated the 25th February 1861, No. 482, especially in the
manufacture and use of bolts with bevelled heads fitting into bevelled slots;
the addition of a neck and flanged bar to my system of bevelled tongues, and
the mode of scarfing the bevelled tongues, all in the manner herein described
and shown in the Diagrams, in so far as the right to any of such last-mentioned.
improvements is not secured to me by my above-mentioned Patent.
+
4. The structure to which armour plates are attached, under which head; I
claim the improvements applicable to the strengthening and supporting of the
spaces inside the skin and between the frames of an iron-ship-or-other-
structure on the same plan as herein described and shown in the Diagrams,
and in so far as any of such improvements or the parts thereof have not been
previously known or used.
...I also. claim the manufacture, use, and application. of yielding or elastic:

page_text: wedge plates, of iron tubular rivetting sheaths, of wedging nuts for bolts, and
of rivetting collars, and the mode of rivetting the ends of bolts therein, all as
herein described and shown respectively in the Diagrams under the Figures 12,
13, 15, 16; and I also claim the use and application of hard bitumenized
felt, cardboard, gutta percha, or other hard and yielding material as a packing
between iron surfaces for the prevention of vibration, in the manner herein
described.
In witness whereof, I, the said George Clark, have hereunto set my
hand and seal, this Seventh day of June, in the year of our Lord One
thousand eight hundred and sixty-two.
GEO. CLARK. (L.S.)