IMPROVEMENTS IN ARMOURED VESSELS, FORTIFICATIONS, AND PROTECTING-ARMOUR
Year: 1881

page_text: A commu-
LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in the
County of Middlesex, Gentleman, for an Invention of << IMPROVEMENTS IN
ARMOURED VESSELS, FORTIFICATIONS, AND PROTECTING-ARMOUR."
nication from abroad by Nathan Beach Clark, of Philadelphia, Pennsylvania,
United States of America.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at
the Office of the Commissioners of Patents on the 15th February 1881.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN ARMOURED VESSELS, FORTIFICATIONS, AND
PROTECTING ARMOUR." A communication from abroad by Nathan Beach Clark,
of Philadelphia, Pennsylvania, United States of America.
The main object of this Invention is to provide war vessels, forts, and other
defences with armour so arranged as to present an effective shield against the shots
of modern ordnance.
In carrying out this Invention I so construct the armour as to deflect the shot
and make no attempt to resist it, the armour presenting acute-angled deflecting
surfaces, which, as they have no direct impact to resist, can be made of such
thickness as to present a certain amount of elasticity, so that I am able to avail
myself of a time element in order to deflect the shot and get rid of them.
This Invention embraces the following features:-
First. A war vessel in which a main shield of convex or other equivalent
deflecting form extending longitudinally from bow to stern, and transversely from
one side of the vessel to the other, combined with a turret or gun shield elevated
or projecting above said main shield, and constructed as hereinafter described, so
as to present to a projectile an acute-angled deflecting surface only.
Second. A war vessel in which a main hull-protecting-shield of convex or other
equivalent deflecting form is combined with a turret or gun shield presenting
acute-angled deflecting surfaces, the said turret being elevated above the shield
so as to leave a practically unobstructed passage for shot between the two.

page_text: Third. A war vessel in which a main hull-protecting shield of convex or other
equivalent deflecting form is combined with a deflecting turret or gun shield
and with cellular bulwarks carried above the main shield and packed with elastic
material.
Fourth. A war vessel in which a gun turret or shield shaped exteriorly so as to
present acute angled deflecting surfaces only, is supported above an armored hull
so as to provide a free passage for shot between the two.
Fifth. A war vessel in which a main hull-protecting shield of convex or other
equivalent deflecting form is combined with a turret or gun shield presenting
acute-angled deflecting surfaces, and capable of turning independently of the
hull.
Sixth. A double convex or plano-convex gun-turret or shield supported above a
hull-protecting shield of convex or other equivalent deflecting form.
Seventh. A deflecting turret or gun shield, the outline of which is described by
the revolution about a common centre of two arcs of circles, and two lines.
tangential to said arcs, and merging to a point.
Eighth. A war vessel in which.a main bull-protecting shield of convex or other
equivalent deflecting form and a deflecting turret or gun shield above the same
are combined with one or more hollow columns or pillars extending between the
shield and turret, and serving as a means of communication between the interior
of the turret and the hold beneath the shield.
Ninth. The main hull-protecting shield of convex or other equivalent deflecting
form and the deflecting turret supported above the same by a series of concentric
tubes through which shot can pass without materially affecting their supporting
properties.
Tenth. The main hull-protecting shield of convex or other equivalent deflecting
form, having an elevated plate forming part of the lower deflecting surface of a
'turret or gun-shield, which is supported by and turns upon the said plate.
Eleventh. The. deflecting turret or gun-shield, the rotating and supporting
structure of which has a spindle forming the plunger of and capable of turning
in a hydraulic cylinder, located beneath the main hull-protecting shield of the
vessel.
Twelfth. The combination of the main hull-protecting shield, the deflecting
turret, and the supporting structure, extending through an opening in the deflecting
shield, and laterally steadied by rollers.
Thirteenth. The combination of the main hull-protecting shield of convex or
equivalent deflecting form, the deflecting turret or shield elevated above the
same, and a supplementary intermediate deflector between the turret and the main
shield.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Henry Johnson in the Great Seal Patent Office on the
12th August 1881.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN ARMOURED VESSELS, FORTIFICATIONS, OR
PROTECTING ARMOUR, AND IN ARMAMENTS CONNECTED THEREWITH." A commu-
nication from abroad by Nathan Beach Clark, of Philadelphia, Pennsylvania, in
the United States of America.
The object of the said Invention is to provide war vessels, forts, and other
defences with armour so arranged as to present an effective shield against the shots
of modern ordnance.
Experiments with modern ordnance and protecting armour have conclusively
demonstrated the fact that the projectiles will pierce the thickest armour a ship can
carry, provided said projectiles strike the armour at or near right angles to its
surface.
This is in accordance with well known laws of resistance and propulsion, for
immense energy is imparted to the projectile without injury to the gun by
propelling the projectile from the breech to the muzzle by means of as high a pressure
of elastic gas as the gun will bear without rupturing, the energy being imparted
gradually during the time of travel of the shot from the breech to the muzzle of
the gun, thereby producing an accelerated motion.
When such a shot is fired against a vertical armour plate or against a plate so
arranged that the shot strikes the same at or near right angles to its surface the
immense energy imparted to the shot, an energy which is the accumulation of
strains upon the entire length of the gun, must be resisted by the armour with
the sharply defined area of the shot, and during the time that it takes the shot
at its immense velocity to travel the almost inappreciable distance that iron
will stretch before breaking, the shot cannot be deflected, and the armour is
penetrated.
Under these conditions guns can always be made superior in power to the
resistance which can be opposed to their projectiles by vertical armour.
Shot striking armour at an acute angle will not penetrate, but glance harmlessly
off, the rule being that the more acute the angle of impingement the less thickness
of armour will be required to deflect the shot.
The feasibility of deflection is shewn by the ricochet shot, which is simply an
oscillation between two opposing forces, the upward deflecting action of the water's
surface and the downward attraction of gravity, the initial energy being absorbed
by the resistance of the air, the deflections, and the final plunge. From the great
distance travelled by a ricochet shot, and the great number of deflections, some
idea may be formed of the small resistance necessary to deflect shot compared with
that required to arrest them by direct impact.
In carrying out the said Invention the armour is constructed so as to deflect the
shot and make no attempt to resist it, the armour presenting acute angled deflecting
surfaces, which, as they have no direct impact to resist, can be made of such
thickness as to present a certain amount of elasticity, so that I am able to avail
myself of a time element in order to deflect the shot and get rid of them.
And in order that the said Invention may be fully understood I shall now
proceed more particularly to describe the same, and for that purpose sball refer to
the several Figures on the annexed three Sheets of Drawings, the same letters of
reference indicating corresponding parts in all the Figures.
In Sheet 1 of the Drawings, Figure 1 represents a longitudinal section partly in

page_text: elevation of a sea-going vessel constructed and having an armament in accordance
with my Invention.
Figures 2 and 3, a plan or deck view and a sectional plan respectively of the
vessel shewn in Figure 1.
Figure 4 is a view similar to Figure 1 of a vessel especially intended for coast
defence; Figures 5 and 6, plan and sectional plan respectively of Figure 4, and
Figure 7, a transverse section on an enlarged scale through the hull and one of
the turrets of the ship Figure 4.
In Sheet 2 of the Drawings, Figure 1 is a transverse section on an enlarged
scale of the vessel shewn in Figure 1, Sheet 1, one of the turrets being shewn
partly in section.
Figure 2 is a plan view partly in section of said turret.
Figure 3, a longitudinal section partly in elevation of the turret.
Figure 4, a plan view partly in section of one of the turrets shewn in Figure 4,
Sheet 1.
Figure 5, a transverse section, and
Figure 6, a longitudinal section of the same.
Figures 7 and 8 views of the conning tower of observation turret shewn in
Figure 4, Sheet 1.
In Sheet 3, Figures 1 and 2 represent a transverse section and plan respectively
of a rotating turret with the requisite mechanism for effecting its movement.
Figures 3 and 4 illustrate a deflecting turret for heavy ordnance mounted "en
barbette."
Figures 5 and 6 shew a V shaped turret which rises directly from the main
shield, and having a single gun mounted en barbette."
"
And Figures 7, 8, and 9 represent different forms of auxiliary sliding deflectors,
with which the deflecting armour may be covered if necessary.
A is the double cellular hull of the vessel, and B a deflecting shield of convex or
other curved form extending longitudinally from bow to stern, and transversely
from one side of the vessel to the other. This shield joins the sides of the hull
some distance below the water line, and rises amidships above said line, the shield
dipping below the water line however at bow and stern. The shield thus presents
a practically constant angle of impingement to a horizontal shot at the water-line,
even as the ship rolls, and the angle is so acute as not to admit of penetration,
the vital parts of the ship, which are located beneath the shield, being thus
effectually protected from injury.
It is preferred to so shape the shield B as to provide for a roll of 20° without
raising the edge of the shield above the water-line, and so that when the vessel is
on an even keel not more than one half of the shield will be above the water-line.
These proportions may however be varied without defeating the object of the
shield.
That portion of the cellular hull or bulwarks of the ship above the shield B is
packed with some elastic and fire-proof substance, cotton treated with alum,
tungstate of soda, or other substance being preferred for this purpose, so that when
a shot penetrates the bulwarks the cotton will expand and fill the opening.
The vessel may have two light decks, as in Figure 1, Sheet 1, and Figure 2,
Sheet 2, the space between these decks forming commodious and well lighted and
ventilated quarters for the officers and crew; or the vessel may have but a single
deck, as in Figure 4, Sheet 1, the quarters in this case being in suitable houses on
the spar deck. The space between the shield and the deck above it is divided into
water-tight compartments for containing ship's stores, which should be packed in
suitable water-tight canisters.
The deflecting shield B rises amidships considerably above the water line, and
effectually prevents shot from entering the hold and emerging on the far side of
the vessel, where projectiles at their exit do the greatest damage, and it should not
therefore be confounded with an armoured deck situated a foot or two below the
water line, which gives no protection to said far side of the vessel, but is a positive

page_text: source of danger from the downward deflection of projectiles striking under it
when the ship rolls so as to bring the edges of said armoured deck above the
water line.
Projectiles entering the side of such vessel above the shield make clear cut
holes, which are immediately filled by the expansion of the elastic cotton packing
of this portion of the hull, the projectile after passing through the light hull
striking the shield B at an acute angle, and being deflected upward and outward
on the far side of the vessel above the water-line.
The shield B is tied in by the chords of its arc, and is supported on any desired
number of longitudinal and transverse bulkheads, and if desired it may extend
beyond the bow in the form of a ram, thus forming in combination with the
cellular bottom and sides of a vessel of unprecedented efficiency and strength.
The cellular bottom may be utilized for water ballasting the vessel, for the
purpose of trimming the shield B or increasing the stability of the ship.
W are the gun shields or turrets, of which the vessel shewn in Figure 1, Sheet 1,
has three arranged amidships, while the vessel shewn in Figure 4, Sheet 1, has two
arranged on opposite sides of the midship line. It should be understood however
that it is immaterial to the Invention how these turrets are arranged.
I will first describe the construction, internal arrangement, and operation of the
turrets and turret connections of the ship, Figure 1, and of the parts carried thereby,
reference being had particularly to the Figures 1, 2, 3, Sheet 2.
Each turret is carried by four hollow pillars or columns a, a, b, b¹, which are
secured to a turn table d adapted to an opening in the main shield B, and guided
and steadied in its rotation therein by anti-friction rollers E. This turntable is
carried by a vertical pillar C, the lower end of which forms the plunger of a
hydraulic cylinder D, resting preferably on the keelson of the vessel so that the
turret has a water bearing, on which it can be turned with comparative ease, any
desired arrangement of gearing being used for this purpose.
Each turret consists of two concavo-convex disks of appropriate thickness, joined
at the edges so as to form both above and below a deflecting surface, presenting an
acute angle to the line of flight of a projectile fired at the turret. The outline of the
turret in fact may be described as produced by the revolution around a common
centre of two arcs of circles and two lines tangential thereto, and merging to a
point. The sharp edge of the turret is pierced at two points for the muzzles of the
guns with which the turret is furnished.
The space between the main shield B which protects the hold of the vessel, and
the turrets W which protect the guns should permit as unobstructed a passage for
the shot as is consistent with the adequate support of the turrets and the require-
ments of a sea-going vessel, for the less resistance that is offered the less injury will
be received.
The cross section of the main shield B at the opening where the turn-table d of the
turret is located is squared with the crown of the shield by thickening the armour
at that point Y, so that the shield at each turret opening presents a flat surface.
At all other points, however, the shield conforms to the arc of a circle, as shewn by
dotted lines.
In order to prevent shot which strike the underside of the turret W from being
deflected downward against the shield B at a penetrating angle, an auxiliary
deflector X is arranged between said turret and the main shield.
Figures 4, 5, and 6, Sheet 2, represent the turret of the ship shewn at Figure 4,
Sheet 1.
This turret is supported upon a central tubular column extending through an
opening in the shield B, the lower part of the tube that is beneath the shield being
cut away at each side so as to permit men to pass up through the tube into the
interior of the turret. The column is contracted at the bottom to form the
plunger C of the hydraulic cylinder D, and is rotated by suitable mechanism acting
upon the wheel at the base of the column.. Lateral steadiness is insured by anti-
friction rollers E, carried by a collar surrounding the opening in the shield B.

page_text: Both of the turrets described above have in the top a central opening covered by
a shield, beneath the edge of which is an observation slit, so that a commanding
officer inside the turret can watch the enemy and govern the operations of the
turret accordingly. The columns a, b, contain hydraulic and speaking tubes and
hydraulic and endless chain.connections to steam steering and turret turning gear.
The ship shewn in Figure 4, Sheet 1, has in addition to the turrets W what I
term a conning shield or observation turret S, which is similar in general construc-
tion to one of the gun turrets, and is supported upon a series of concentric tubes of
plate iron, the thickness of which is not sufficient to prevent the free passage of
shot completely through the entire series, which may be severally riddled without
materially affecting their supporting properties.
Access to the interior of the conning shield is effected through a central trunk S¹
rising from the shield B, and in order to lessen shocks as much as possible, a gap is
left between the shield and the trunk. To deaden concussions the interior of the
conning shield S is thickly padded, and, if desired, the interior of the gun turrets
may be similarly padded. The commanding officer located in the conning shield is
provided with speaking tubes and other appliances, whereby he can control all of
the movements of the ship and turrets.
In Figures 1 and 2, Sheet 3, is shewn a turret, the underside of which carries.
anti-friction roller running on tracks on a circular plate, supported above the main
shield B by a central trunk and a series of concentric tubes similar to those just
described in connection with the conning shield, this plate forming part of the under
deflecting surface of the turret. This turret is rotated by mechanism arranged
within the turret, this mechanism consisting in the present instance of a vertical
shaft, actuated by an air or hydraulic engine, and carrying a pinion which gears
into an annular rack on the supporting plate.
In Figures 3 and 4, Sheet 3, is shewn a deflecting turret with the guns H
mounted "en barbette," the guns being sufficiently heavy to avoid, being injured
by shot. The turret is supported and operated in substantially the same manner
as that shewn in Figure 6, Sheet 2.
The advantage of this form of deflecting turret is that it admits of the use of
very large guns, and places the weight of the armour lower in the ship, which is
favorable to stability.
tr
"
In Figures 5 and 6, Sheet 3, is shewn a single gun mounted en barbette
on a V shaped, which rises directly from the main shield, the rotating and
supporting devices being substantially similar to those herein before described.
This form of armour is best adapted to rams and gunboats armed with a single
large gun on the bow which can be constantly trained on an enemy. The turret
deflects projectiles laterally, instead of vertically as in the double convex turret.
Figures 7, 8, and 9 shew different forms of auxiliary sliding deflectors with
which if found necessary the deflecting armour may be covered as a safeguard
against square headed punching shot, which might otherwise pierce such armour.
The auxiliary plates are lightly secured to the main armour, and when struck are
detached and slide upward so as to deflect the shot from its course.
Although the turrets have been described as being either double convex or
V shaped, a plano-convex turret may be used to advantage in some cases, the plane
side being on the bottom, and in some ships a fixed casemate for protecting a row
of guns arranged on the broadside of the vessel may be combined with the main
shield B; for instance, on the spar deck of the vessel may be built a deflecting shield
similar to the shield B, and covering the guns, the underside of the spar deck
being plated with armour to prevent injury from shot deflected upward from the
shield beneath. This fixed casemate need not extend throughout the length of the
vessel, but only so far as is necessary to protect the guns.
Although the said Invention has been described and illustrated as applied to war
vessels, it will be obviously understood that some of the main features of the
Invention are equally applicable to land fortifications and armoured defences
generally.

page_text: I am aware that it has been proposed to construct a gun-shield or turret with
opposite pointed ends and straight parallel sides, such turret being mounted upon
long cylinders or floats, to the space between which and under the turret the sea
had free access.
Such a turret however differs from the V-shaped turret in lacking the power of
being turned independently of the hull of the ship, so that while in the vessel the
deflecting surface of the V shaped turret can be kept constantly presented to an
enemy by simply turning the turret, the patented vessel necessitates the manoeuvring
of the entire ship in order to keep the turret head on. The supporting cylinders
or floats of the patented vessel moreover are essentially different from the shielded
hull of the vessel.
I am also familiar with the Gruson armour, consisting of cast iron plates of
convex form and great thickness chilled to render them hard, and presenting a
rigid resistance to shot. The armour differs essentially from the shields, which are
formed of comparatively thin plates of wrought iron or steel, and present an elastic
resistance to shot so that it is enabled to avail a time element in deflecting
and getting rid of said shot.
In illustrating the mode of carrying out the present Invention it has been found
convenient to shew in the Drawings certain features relating to ordnance described
in the Provisional Specification filed by me with my application for Letters Patent
dated the 7th March 1881, No. 975.
Having now described and particularly ascertained the nature of the said
Invention, and the manner in which the same is or may be used or carried into
effect, I would observe in conclusion that what I consider to be novel and original,
and therefore claim as the Invention secured to me by the bereinbefore in part
recited Letters Patent is,-
First. A war vessel in which a main shield B of convex or other equivalent
deflecting form for protecting the vital parts of the hull is combined with a turret
or gun shield elevated or projecting above the said main shield, and constructed so
as to present to a projectile only an acute angled deflecting surface, substantially as
herein before described and illustrated in the accompanying Drawings.
Second. A war vessel in which a main hull-protecting shield B of convex or
other equivalent deflecting form is combined with a turret or gun shield presenting
acute angled deflecting surfaces, the said turret being elevated above the shield so
as to leave a practically unobstructed passage for shot between the two, substantially
as hereinbefore described and illustrated in the accompanying Drawings.
Third. A war vessel in which a main hull protecting shield of convex or other
equivalent deflecting form is combined with a deflecting turret or gun shield, and
with cellular bulwarks carried above the main shield and packed with elastic
material, substantially as hereinbefore described and illustrated in the accompanying
Drawings.
Fourth. A war vessel in which a gun-turret or shield B shaped exteriorly so as
to present acute angled deflecting surfaces only is supported above an armoured.
hull so as to provide a free passage for shot between the two, substantially as
hereinbefore described and illustrated in the accompanying Drawings.
Fifth. A war vessel in which a main hull-protecting shield B of convex or other
equivalent form is combined with a turret or gun-shield presenting acute angled
deflecting surfaces, and capable of turning independently of the hull, substantially
as hereinbefore described and illustrated in the accompanying Drawings.
Sixth. A double convex or plano-convex gun turret or shield supported above a
hull protecting shield B of convex or other equivalent deflecting form, substantially
as herein before described and illustrated in the accompanying Drawings.
Seventh. A deflecting turret or gun shield, the outline of which is described by
the revolution about a common centre of two arcs of circles and two lines
tangential to said arcs, and merging to a point, substantially as hereinbefore
described and illustrated in the accompanying Drawings.
Eighth. A war vessel in which a main hull protecting shield B of convex or

page_text: other equivalent deflecting form, and a deflecting turret or gun shield above the
same, are combined with one or more hollow columns or pillars extending between
the shield. and turret, and serving as a means of communication between the
interior of the turret and the hold beneath the shields, substantially as hereinbefore
described and illustrated in the accompanying Drawings.
Ninth. The main bull-protecting shield B of convex or other equivalent
deflecting form, and the deflecting turret supported above the same by a series of
concentric tubes through which shot can pass without materially affecting their
supporting properties, substantially as herein before described and illustrated in the
accompanying Drawings.
Tenth. The main hull-protecting shield B of convex or other equivalent deflecting
form having an elevated plate forming part of the lower deflecting surface of a turret
or gun-shield which is supported by and turns upon said plate, substantially as
bereinbefore described and illustrated in the accompanying Drawings.
Eleventh. The deflecting turret or gun shield, the rotating and supporting
structure of which has a spindle C forming the plunger of and capable of turning
in a hydraulic cylinder D located beneath the main hull-protecting shield B of the
vessel, substantially as hereinbefore described and illustrated in the accompanying
Drawings.
Twelfth. The combination of the main hull-protecting shield B, the deflecting
turret, and the supporting structure extending through an opening in the deflecting
shield B, and laterally steadied by rollers E, substantially as herein before described
and illustrated in the accompanying Drawings.
Thirteenth. The combination of the main hull-protecting shield of convex or
equivalent deflecting form, the deflecting turret or shield elevated above the same,
and the supplementary intermediate deflector X, substantially as hereinbefore
described and illustrated in the accompanying Drawings.
In witness whereof, I, the said John Henry Johnson, have to this my
Specification set my hand and seal, this Eleventh day of August, One
thousand eight hundred and eighty one.