IMPROVEMENTS IN THE USE, COMBINATION, AND APPLICATION OF IRON AND TIMBER AS ARMOUR FOR VESSELS OF WAR AND FORTIFICATIONS
Year: 1862

page_text: LETTERS PATENT to James Chalmers, of 8, Knight's Place, Vauxhall,
London, for the Invention of "IMPROVEMENTS IN THE USE, COMBINATION,
AND APPLICATION OF IRON AND TIMBER AS ARMOUR FOR VESSELS OF WAR AND
FORTIFICATIONS."
Sealed the 15th May 1863, and dated the 19th November 1862.
PROVISIONAL SPECIFICATION left by the said James Chalmers at the
Office of the Commissioners of Patents, with his Petition, on the 19th
November 1862.
I, JAMES CHALMERS, of 8, Knight's Place, Vauxhall, London, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN THE USE, COM-
BINATION, AND APPLICATION OF IRON AND TIMBER AS ARMOUR FOR VESSELS OF
WAR AND FORTIFICATIONS," to be as follows:-
This Invention has for its object the obtaining of great resistance to the
penetrating and destructive power of projectiles, and consists of the following
improvements: First, the adoption of an inner or second armour plate,
having a cushion of timber planking or other elastic or yielding substance
between it and the side of vessel or fortification; second, an improved method
of backing or supporting the outer or principal armour plate. This improve-
ment consists of alternate layers of planks of timber and ribs of iron, which
shall be built up and placed between the outer and inner armour plates, and
have their edges towards and touching the said armour plates, so that bearing

page_text: on the inner plate this compound backing of iron and timber may fill the space
between the two armour plates, and present the outer edges of the planks and
ribs as a support for the outer or principal armour plate. I propose that the
said layers be bolted together laterally with bolts at short distances apart, so
that the bolts may offer resistance to the passage through the backing of any
projectile that may penetrate the outer armour plate. In order to facilitate
the construction of this compound backing, and to secure a compact and
united body, I propose in binding the said layers together to use bolts with
coupling nuts, which nuts shall be of sufficient depth not only to screw up the
bolts which unite two or more of the aforesaid layers together, but also to
receive the ends of other bolts or lengths of bolts, which in turn after passing
through two or more layers, shall in a similar manner be screwed up, and so
on, until the desired surface be covered. The ribs of iron may be plain plates
of the size required, but I propose to adopt a form similar to the annexed section
or such other section as will tend to bind or unite with the timber, the
planks in either case being made to fit to the ribs. The said planks and
ribs may be put together either with or without an adhesive substance
between them, but I prefer an adhesive 'substance such as would tend to
unite them into a compact mass, and also serve to neutralize or prevent
such deterioration as might otherwise result from the contact of timber
and iron.
The third improvement refers to methods of fastening the principal armour
plate, of which one method is by through bolts to be secured by nuts inside
of the vessel or fort; but as the tendency of bolts subjected to the vibration
caused by the impact of projectiles is to break at the thread, I propose using
what is generally termed a square thread, the depth of thread being about one
half of its breadth. The head of the said through bolt may have a stepped
conical neck, such as I have described in the Provisional Specification of my
Invention for " Improvements in Armour-plating Ships of War and Fortifi-
cations," bearing date the 28th day of October 1862, and numbered 2897, or
it may have a square or bevelled shoulder, or the bolt may have an ordinary
countersunk head. I propose that the bolt shall pass through a socket which
shall bear on the outer or principal armour 'plate under the neck or shoulder
of the bolt, and in order to give the said socket a firm bearing; I proposé.to
use a step block of such a breadth as will fit in between two of the iron ribs,
said block to be about six inches in length and two inches thick. Through a
hole in this block the bolt shall be passed, and the socket surrounding the bolt.
shall bear upon the said block, which shall in turn bear upon the inner armour
plate.

page_text: The backing described under the second head may also be used without
through bolts in connection with fastening bars, such as I have described in
the last clause or paragraph of the Provisional Specification afore mentioned,
bearing date the 28th day of October 1862; namely, a bar with a longitudinal
head placed between the edges of the outer armour plate, which longitudinal
head shall fit into chamfers taken off the outer corners of the edges of the
outer armour plates. A T-head bolt may be let into a corresponding notch in
the inner edge of the said bar, for attaching the bar and armour plate to the
vessel or fort; or the backing aforesaid may be used in connection with other
methods of fastening.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Chalmers in the Great Seal Patent Office on the
18th May 1863..
TO. ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
CHALMERS, of 8; Knight's Place, Vauxhall, London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Nineteenth day of November, in the year of our
Lord One thousand eight hundred and sixty-two, in the twenty-sixth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said James Chalmers, Her special licence that I, the said James Chalmers,.
my executors, administrators, and assigns; or such others as I, the said James
Chalmers, 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,
COMBINATION, AND APPLICATION OF IRON. AND TIMBER AS ARMOUR FOR VESSELS OF
WAR AND FORTIFICATIONS," upon the condition (amongst others): that I, the
said James Chalmers, 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 James Chalmers, do hereby declare
the nature of my said: Invention, and in what manner the same is to be per-

page_text: statement:-
This Invention has for its object, improvements in the construction and
fastenings of armour for ships of war and fortifications in order to obtain a
more effectual resistance to the penetrating and destructive power of projectiles,
and is described as follows:-Commencing at the skin or side of the ship, or
wall or outer surface of a fort or work to be protected by armour, I first apply
what in my Provisional Specification of this Invention I term "A cushion of
timber planking or other elastic or yielding substance," in order to lessen the
rigidity of the structure and to prevent the injurious effects of vibration caused
by the impart of projectiles on the armour plates, from destroying the frame
and fastenings of the ship or fort or the fastenings of the armour plates.
Outside of and covering the said cushion I attach an outer plate or skin,
which may be more properly termed an intermediate or second armour plate,
which, when secured to the side of the ship or fort, will form a surface on
which the compound backing herein-after described shall bear. This com-
pound backing shall consist of alternate layers of timber planking.and iron or
steel ribs or plates, which shall be built up outside of the said second armour
plate, one of the edges of the said layers bearing against the plate, whilst the
other edge is presented as a support. or backing for the outer or principal
armour plate. I propose that the said layers be bolted together laterally, and
in order to secure a united body and to facilitate the construction of this
compound backing, especially when following the curved lines of a ship, I
propose, in binding the said layers together; to use bolts in short lengths with
coupling nuts, which nuts shall be of sufficient depth, not only to screw up
the bolts which unite two or more layers together, but also to receive the ends
of other bolts or lengths of bolts, which, in turn, after passing through two or
more layers, shall in like manner be screwed up, and so on, until the desired
surface be covered. The ribs of iron may be plain plates of the size required,
though I would prefer and. recommend a rib or plate similar to. the section,
Figure 12 on the Drawing, or such other section as would tend' to bind the
layers together, so that when force was applied to their edges they would act
as a united body in resisting it. The planks in either case would be made to
fit the ribs: I further propose that the aforesaid. layers be put together with
an. adhesive substance: between them, though they may also be used without
such substance; but I would prefer and recommend the use of india-rubber
glue or marine glue, or such other substance.as will make the two surfaces
cohere and at the same time serve to neutralize or prevent such deterioration
as might otherwise result from the contact of timber and iron; and for the

page_text: same reasons I recommend the use of the said india-rubber glue or other
suitable substance between all surfaces when iron and wood come in contact
when practicable. With regard to uniting the alternate layers of planks and
plates aforesaid which form the compound backing, the said glue or other.
substance may sometimes unite them sufficiently without bolts, in which case
the lateral bolts aforesaid may be dispensed with, and the necessity for holes
in the plates and planks avoided. The aforesaid compound backing, as it is
built up, can be attached to the ship or fort by bolts in the ordinary manner,
and the outer surface thereof formed by the edges of the planks and plates
will form the bed or backing for the outer or principal armour plates. In
applying these plates I would recommend that the surface of the backing and
the inner surface of the plate be coated with a thin coating of india-rubber
glue or other suitable substance for the reasons herein-before stated. . In
securing the armour plates to the ship or fort I propose, first, to use through
bolts with nuts and screws either with or without a jam nut; and as the
prevailing tendency of bolts subjected to the vibration caused by the impart of
projectiles is to break at the thread close to the nut rather than to strip or
overhaul the thread, as frequently occurs when bolts are subjected to heavy.
strains, I propose to use a shallow thread of the form generally termed a
"square thread," the depth thereof being only about half of the breadth. The
object I have in view in adopting a shallow thread is to save the section of the
bolt from being cut away and weakened by a deep thread, and I consider the
thread shown in Figure 4 the best proportion for the peculiar work of the
bolt; still I do not limit myself to this peculiar form of thread, for this part
of my Invention has for its object to preserve the section of the bolt at the nut
as large as possible, which may be done by a fine or shallow thread of some
other form, though I prefer the one shown in the Drawing for this special
purpose. I also propose to adopt a similar thread for the same reasons for
other purposes, especially in the lateral bolts and nuts, as in Figure 7., As
regards the thickness or diameter of the armour plate or through bolt, it
should in no case be less than half of the thickness of the plate to be secured
by it, though I do not limit myself as to size.. The head of the bolt may be
of any form best suited for the work in question, a smooth cone, as in Figure 4,
or a stepped cone, as in Figure 5, or any other suitable form.
A second method of attaching armour plates to ships or forts which I
propose is by fastening bars such as I have described in the Provisional
Specification of my Invention for "Improvements in Armour-plating Ships of
War and Fortifications," No. 2897, bearing date the Twenty-eighth day of
October, One thousand eight hundred and sixty-two, and: as the said. Pro-

page_text: visional Specification was allowed to lapse, but was not published until after
the date of the Specification of this Invention, I here introduce the description
of the said fastening bars. In cases where through bolt fastenings would be
injurious, as in the case of narrow armour plates, or otherwise, the armour
plate shall be fastened to or through the backing by fastening bars of two
inches in thickness, more or less, which bars shall be placed between the
edges of the armour plates (see Fig. 9), the outer corners of the edges of
which shall be chamfered, and the outer edges of the fastening bars shall be
provided with a T or longitudinal head corresponding with the chamfers in
the edges of the armour plates; the said fastening bars to be 10 inches in
depth, more or less. In order to secure the said bar to the ship or fort, bolts
with T-heads shall be let into a notch in the inner edge of the said bar (see
Fig. 10), which notch shall correspond with the width of the T-head of the
bolt. The end of the T-head bolt shall be secured with a nut, as in the case
of the through bolts afore-mentioned. The notch in the bar shall be one
inch, more or less, deeper in the lengthway of the bolt than the size of the
bolt head, so that there shall be a space between the head of the bolt and
the metal of the fastening bar, in order that when a projectile strikes the bar
opposite a bolt, it may not communicate the jar to the bolt.
- The socket and step-block to support the armour plate under the bolt hole,
referred to in the Provisional Specification of this Invention, I have abandoned,
and therefore disclaim the use of them.
DESCRIPTION OF THE DRAWINGS.
The following reference to the accompanying Drawings will explain more
fully the nature of my Invention:-Fig. 1 represents a vertical section of a
portion of a ship's side, with the improvements herein-before described.
a represents the armour plate; b, the timber planks, and c the iron ribs of the
compound backing, which are bolted together by the bolts d, shown on a
larger scale in Figures 9 and 10; this compound backing can be secured to
the ship's side independently of the armour plates by the bolt e, seen in Fig. 3.
fis the intermediate or second armour plate, and g, Fig. 3, a bolt which may
be used for attaching the same to the ship, independent of the backing. The
cushion h, in Figures 1, 3, 9; and 10, is of timber, and in Fig. 11 it represents
felt, india-rubber, or any other suitable substance. Fig. 2 is an elevation, with
a port hole, of a portion of a ship's side, and Fig. 3 is a sectional plan of the
same; Fig. 4 represents the thread and section of nut of the through fastening
bolt; Fig. 5, a stepped conical head of bolt; and Fig. 6, plan of nut;
Fig. 7 shows the ends of the two bolts d, Fig. 9, joined in the coupling nut,

page_text: and Fig. 8 is a plan of the nut; Fig. 9 is a vertical section of part of a ship's
side, showing the mode of attaching the plates by the fastening bars afore
mentioned; and Fig. 10 is a sectional plan of the same, i being the bar and k
the T-head bolt; Figures 12 and 13 are sections of the ribs or backing plates,
which are seen on a smaller scale in Fig. 9.
Figures 1, 2, and 3 are on a scale of inch per foot; Figures 9, 10,
and 11 are on a scale of 1½ inches per foot; and Figures 4, 5, 6, 7, 8, 12,
and 13 are full size.
The sizes and dimensions given in the Specification and Drawings are
calculated for ship armour where there are limitations as to weight; but for
land forts or batteries the dimensions and weight can vary with the circum-
stances of the case.
The objects aimed at in the combinations and arrangements of materials
herein-before described, are to deaden and disperse or distribute over an
extended area the power or work in the projectile at the point of impart, as
illustrated by the dotted lines leading from the shot m in Fig. 3, to
preserve the armour plates as much as possible from buckling, penetration,
and fracture, and to secure the integrity of the fastenings of the ship or fort,
and of the armour plates intended to protect them.
I wish it to be understood that I do not confine myself to the precise details
and dimensions set forth in the foregoing description of my Invention, or in
the accompanying Drawings, also that I do not limit the application of my
compound-backing" or "second plate and cushion" to the particular methods
of fastening armour plates herein-before described, nor the application of my
fastening bolt or bar to the aforesaid methods of backing armour plates.
In witness whereof, I, the said James Chalmers, have hereunto set
my hand and seal, this Eighteenth day of May, in the year of our
Lord One thousand eight hundred and sixty-three.
JAMES CHALMERS. (L.S.)