The Sun.
London, England, 1866-05-11 00:00:00

Ships Guns and Armour.

There is no subjict which, from a national point of view,
offers so large a field for observation and discussion as the
armour and armament of the broadside-gun ships of our
ironclad fleet, from the day on which the Warrior was
launched to the present, with our latest addition, the Belle-
rophon, just anchored at Spithead. The Warrior and
others designed about the same time were built to carry the
then most powerful gun—the 95cwt. 68-pounder, and were
clothed with proportionately defensive armour of 41 inches
in thickness. But they were simply "box" armouredships,
carrying their guns behind their armour only amidships,
and leaving their ends, with the water-line before and
abaft the central box, unprotected by armour. With the
Hector and. Valiant class this defect was in a manner reme-
died, the former carrying a band of plating entirely round
the main or gun deck, and the lattergiving more protection
to the water-line. Then came the wholly armoured ships,
of iron and wooden construction respectively, the former
represented grandly by the Achilles, Minotaur, &c., and
the latter by the "make-shift" squadron of the Caledonian
and Royal Oak class. With the iron ships was introduced
an increase in the armour-plating to 5 and' 51 inches, and
the Achilles was given as her armament the new wrought-
iron 9-inch smoothbore or "Somerset" gun in the place of
the cast-iron 68-pounder and the 110-pounder breech-load-
ing Armstrong, the latter never having been, at,close guar-•
ters, with rapid firing, considered a match for the old cast-
iron smoothbore 8-inch. The trials of the Royal Sovereign
and the feats of the American Monitors naturally gave birth
to enlarged ideas on the arming and clothing of iron-
clads. The turrets of the Royal Sovereign carried
12-ton guns, but it was also evident that they could
carry and work ordnance of double the weight,
while the tremendous shot-resisting power which they
must possess with their 10 inches of iron round the face
of the turret round the gunports was very materially
increased by the shot-deflective power given by their cir-
cular form. In the discussion that ensued on the turret
versus broadside question it was felt from the first onset by
the advocates of the latter principle, as indeed by every
one, that 51 inches of armour on 10 inches of teak backing
on the sides of even such noble and swift ships as the
Achilles and Minotaur would be wholly incapable of resist-
ing projectiles from the 12-ton smoothbore gun, and must
be still further defenceless against the same weapon when
completed in its promised form as a 9-inch rifle.
The present Chief Constructor of the Navy, on his ac-
cession to office, accepted at the same time the acknow-
ledged soundness of the principle that in designing the
broadside-gun ships for the future they must be made to
approximate as nearly as possible to turret vessels in
strength of sides arid power of gun. In the endeavour to
carry this principle into effect we have abandoned the
wholly armoured system of the Achilles and Minotaur
class, and gone back to our first principle—the box ar-
rangement of the Warrior ; but now a box with a water-
line belt, increasing at the same time the thickness of the
box and belt armour. With the Bellerophon this central
armour has reached 6 inches on a side of greater strength
than the Minotaur's, and with a supporting inner skin of
11 inches. But it is in the designs of the Hercules, now
being laid down at Chatham dockyard, that we have
reached our maximum thickness of armour at present, the
central armour of this ship being no less than 9 inches in
thickness. It is an undoubted truth that the armour of
our ships should rightly, to make their defensive equal to
their offensive powers, always be equal in thickness to the
diameter of the bore of their rifled guns. Thus, the Her-
cules, with 9-inch armour plating, may be considered as
invulnerable, in all parts where she is coated with ar-
mour, to shot or shell from rifled guns whose bore's di-
ameter does not exceed that thickness, and as the Hercules
will carry that description of gun the toughness of her skin
and the sharpness of her teeth may be considered to be in
just proportion to each other. Not so, however, with the
Bellerophon or the Minotaur, the one a partially and the
other a wholly armoured ship. Both ships will carry a
maximum weight of 121 tons, having a diameter of rifled
bore of 9in., and a minimum sized gun of 6-} tons with a
iin. diameter of rifled bore. Now, the strength of these
vessels' sides is not in proportion to the power of the guns
they carry, and the cuirass of the ship is therefore deficient
in thickness of metal, by the rule that, whatsver gun we
may mount on the broadsides of our ships, an enemy can
certainly do the same. The Hercules is, as already ob-
served, invulnerable to all projectiles from guns that can
at present be carried on the broadside, but she is vulner-
able to almost any description of gun, from an ordinary
boat's gun upwards, in all the unarmoured portions of her
hull, as also is necessarily the Bellerophon and all other
ships not wholly armoured. The argument is used, with
almost irresistible force, that it would be impossible to
build a ship to carry 9in. armour all round, and that the
only course remaining is to concentrate the armour the ship
can carry round her gun battery and her water-line, leav-
ing the forward and after parts of the ship to be riddled
through and through by the enemy's shot at their pleasure,
the officers and crew being in safety in the armour-enclosed
central battery, and the safe flotation of the ship secured
by the water-line belt of armour. So far as shot alone is
concerned, this argument is reasonable enough, but it cannot
be entertained for a moment by any one who has witnessed
the havoc caused by a shell filled with a large bursting charge
exploding by a percussion fuse in the side or on the deck Of 1
a wooden ship, as such missiles would explode in the un-
armoured sides or on the 'tween decks of a partially
armoured ship. In illustration of this it is only necessary
to suppose the Bellerophon engaged with an enemy of equal
tonnage but of rather superior speed, and with guns that
would not penetrate the Bellerophon's central armour.
The enemy in this case would have nearly 160 ft. in length
by about Oft. in breadth on each side of the Bellerophon
unarmoured and open for his " shell practice." Having
the superiority in speed, he woubl take the choice of posi-
tion on the bow or quarter, where he would be perfectly
safe from the 9-inch rifles in the Bellerophon's central
battery, and ply the unfortunate ship with shell with 151 b.,
201 b., or or ,n 301 b. bursting charges, which must destroy
the ship by obtaining entry through this unprotected por-
tion of her skin, while the ordnance amidships would be
useless to defend her, owing to the ship's inferiority in
speed to that of the enemy.
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until now they have reached a degree of
perfection little
dreamt of when the famous Warrior target made its first
appearance at Shoeburyness. It is not, however, by the
results of the firing at Shoeburyness that a correct estimate
may be formed of the quality of the armour on the
sides
of the ironclads of England. Such estimate can only be
truly formed from the results of the testing of armour
plates at Portsmouth. At Shoeburyness all targets have
their plates specially made for them, no cost is spared
in their composition and manufacture, and they neces-
sarily possess an exceptional character, but they are
far from representing in their strength the strength of
the armour of her Majesty's ships. On the contrary,
the plan pursued in the supply of the plates for trial
at Portsmouth is of so unexceptionable a character that
they do
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to supply a certain quantity of armour plates of not less,
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say, than A 3 quality on trial at Portsmouth. An inspector
is sent down to the works by the Admiralty, who watches
the whole process of manufacture of the plates, and com-
municates with the Admiralty. One day, unannounced,
Mr. Luke, the superintending inspector of such matters to
traamheoduAeth,domwrirditeahrlstya;hwe atwlkos iuto the works, and selecting one or
trial under fire.
two plates from among a batch of some perhaps 20 or 30
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tthhe selection of a sound plate. We will
suppose that a plate has arrived at Portsmouth for trial.
It is drilled first in the dockyard with the requisite num-
ber of bolt holes, and then iorwarcio4 on board the testing ,

ship, the Thunderer, where it is bolted on to a timber
bulkhead, and fired at from 68-pounder solid shot guns,
with 131 b. of powder and a 68-pound east-iron shot, at
only 30 feet distance. Five shots are fired at the plate
under trial, and these are so planted on the plate that all
five strike in a space 18 inches square. When armour-
plates were first tested at Portsmouth the best plate would
have been split up in all directions and utterly destroyed
under such a test. Now a plate gaining an A 1 character
exhibits no opening of its metal outside the indentations
of the shot, nor does the greatest depth of indent exceed
21 inches. These trials have, however, become invested
with increased interest since the maximum thickness of
our ships' armour has been increased from 51 to 9 inches.
Some time since, when the maximum thickness of a
ship's armour was sin., the Admiralty gave an order for
several hundred tons of 41in. plates to Messrs. Petin,
Daudet, and Co., of France. The majority of these plates
proved to be of unusual excellence in quality of metal,
although somewhat rough in manufacture. In what may
be termed the competitive trials which followed upon the
receipt of the plates at Portsmouth the plates supplied by
John Brown and Co., of Sheffield, barely succeeded in beat-
ing the French plates and securing the severely contested
honours. There can be no doubt now that this purchase
of plates from a French manufacturer by the Admiralty
gave a wholesome stimulus to English makers, and has re-
sulted in the present acknowledged superiority of English
plates over all others manufactured in Europe or America.
Our own proof-test has reached what may be considered
the maximum of possible strength, and as the severity of
the test has been thus increased, so also it may be justly
said has the quality of the plates sent in for trial also in-
creased in quite a proportionate ratio. Of this some trials
on board the Thunderer lately furnished examples suffi-
ciently conclusive to convince the most sceptical. The
day was fixed for the trial of two rolled plates sent in by
the Mersey Steel and Iron Company. Captain Key and
his staff arrived on board the Thunderer at 11 amt., and
the firing immediately commenced at the plates from Bin.
95cwt. smooth-bore guns, with spherical shot of cast
iron, with 131 b. powder charges, the distance between
the guns' muzzles and the plates being 30 feet. Each plate
received five shots, each of the five shots overlapping, the
five blows being thus delivered on one part of the plate
about 18 inches square. It will be sufficient to say with
reference to these plates that although, perhaps, not quite
equal to some of the same thickness that have been tested
lately, they were nevertheless of very excellent quality.
The damage caused by the five shots in each instance was
confined, or very nearly so, within the circumference of
the shot indents, and they received an A 2 classification in
Captain Kay's official report of the trials to the Admiralty.
The important incident of the day, to which reference has
been made, followed immediately upon the trial of the
Mersey Company's 6-inch plates in the firing of a steel
elongated shot weighing 1521 b., with 301 b. of powder, from
an Armstrong shunt rifled-gun of 8 inches diameter,
against a 9-inch plate, manufactured by John Brown and
Co., of Sheffield, for the Hercules frigate, at the test dis-
tance, on board the Thunderei, only 30 feet. The plate
had been tested on board on the 17th inst., when 12 shots
from the 95 cwt. 8-inch smooth-bore gun, each shot fired
with 131 b. of powder, were planted on the face of the plate
in a space, measuring from extreme angles of indents, of 34
inches by 19 inches. The first five shots, all planted in a
cluster, only produced an indentation in the deepest part
of 2,1 inches, and the seven shots that subsequently fol-
lowed failed in producing any greater depth, or even in
raising the slightest sign of a crack, surface, or other-
wise in the metal, the iron merely spreading under the
successive blows from off one indent to the other, accord-
ing as the shots fell. It was this extraordinary tenacity
and shot-resisting power exhibited by the plate that in-
duced the Controller of the Navy to order it to be
tried with the 8-inch Armstrong shunt rifled gun, it s
enormous powder charge and steel bolt, and with the
plate bolted on its timber backing at, as may be truly consi-
dered, the gun's muzzle. Notwithstanding the wonderful
success of the plate when tested with the 68-pounder gun,
it was the opinion of all present on board the Thunderer
that the minimum amount of mischief that would be done
by the steel bolt from the 8-inch rifled gun would be its
thorough penetration and burying itself in the timber
backing behind the plate. The latter still remained bolted
on its backing in the same position as when previously
fired at, the spot selected:for trial on that occasion being the
right centre of the plate. On the present occasion the
shunt gun was laid for the left centre, and, when all was
proclaimed ready, fired. A heavy fall and rumble upon the
deck of the proof-room overhead followed the report of the
gun's discharge, and upon Captain Key and his officers
entering the room (the guns on board the Thunderer being
fired from the deck below), the steel bolt was found upon
the iron deck within about six feet of the plate, and " set
up," or compressed, 21 inches short of its original length
with a deep cross crack across its base. It was made from
the best " Firth " steel, and had done all that a steel shot
could do even from the 8-inch shunt rifled gun with its
301 b. powder charge, but it had evidently not penetrated
far into the plate. An inspection of the latter showed that
the shot had struck 22 inches from the plate's upper edge,
24 inches from its lower edge, and 39 inches from the left-
end edge. The greatest depth reached by the steel bolt
was 3 2-10 inches, but the mean depth might be taken at
one-tenth less. The appearance of the metal within the
indentation, and of the edge round it on the plate's surface,
exhibited its excellent quality. Within the indentation it
was all bright and smooth as polished steel, from its com-
pression by the terrible blow of the steel bolt, and without
any crack or flaw of any kind on the surface, except a
coppery tinge round the outer circumference of the inden-
tation, where the copper studs on the steelsbot had come in
contact with the iron of the plate. All round this indenta-
tion the iron was squeezed out in a kind of lip to the cir-
cular indent to about three-quarters of an inch above the
plane of the surface of the plate. This was all the damage
done, and the plate still hangs in its old position, as im-
pervious to the 8-inch rifled gun with steel bolts, as ships'
armour, as it had formerly proved to be to iron shot from
the 8-inch smooth-bore gun. It was the severest test to
which a plate had ever been subjected at Portsmouth, and
the plate itself has undeniably proved superior to any
other that has yet been placed under fire at that port, from
the first plate tried for the warrior down to the present
time. It may be interesting to state here that under the
new regulations introduced with the Thunderer the classi-
fication of all plates sent by manufacturers for trial on
board the Thunderer is in a great measure regulated by
the " standards," which have been fixed up in the proof-
room of the Thunderer for that purpose. These "stan-
dards" consist of the best known specimens of plates of
their respective thicknesses that have been sent for trial
at any time to Portsmouth. As standards they are removed
and superseded by others of greater excellence as they are
met with in the course of time, the present standards on
board the Thunderer being —for 41 inch plates, a part of a
plate supplied by John Brown and Company, of Sheffield,
for the Lord Warden ; for 6-inch plates, a part of a plate
supplied by Charles Cammel and Co., of Sheffield, for the
Hercules; and for the standard for plates of a greater
thickness than 6 inches will now be added the 9-inch plate
of John Brown and Co., which underwent such an excep-
tionally severe test on its trial.