The Sun.
London, England, 1863-04-29 00:00:00

)N, WEDNESDAY EVENING, APRIL 29, 1863.

EXPERIMENTS AT SHOEBURNNESS.

Another of those experiments which occasionally
yield such important results with regard not only
to armour. plate?, but to the still more difficult and
important question of how best to support them
from behind took place on Monday at Shoebury•
ness. This experiment was made by older of the
Iron-plate Committee, all the members of which
were present, together with many officers and others
interested in the construction of armour-coated ships
of war. The target fired et was constructed at the
Mille all Iron works from the designs of Mr. Chal-
mers, and, in addition to its other qualifications, it
possessed the rare merit of having keen built en-
tirely at its inventor's own expense—a most unusual
circumstance at Shoebury, where the crowd of in-
ventors and patentees seldom evince sufficient con-
fidence in the crotchets they compel the authorities
to try to venture anything themselves towards the
cost of the trial. The target was 13 feet long by
10 feet broad, faced externally with hammered
armour-plates 31in. thick. Behind these were laid
longitudinal teak beams 10in. wide by about sin.
deep, a web or flange of wrought-iron Zin. in thick-
ness passing between each beam, and being rivetted
to a plate 11,in. in thickness at the back. Behind
this plate again came another pad of teak sin. thick,
which rested against the skin of the ship—the same
thickness as that of all our ironclads, hs of an
inch, and behind this were the usual upright beams
or iron ribs of the vessel. Thus it will be seen that,
though the target was apparently a light one from
its external plates being only 34in. thick, yet in
reality it had, after all,4in. of iron in it, with 15in.
of teak, exclusive of the longitudinal cellular iron
webbing we have mentioned between the teak
beams, which, though not nominally called upon
to resist the shot, yet, in truth, aided the resistance
enormously, by distributing the force of the con-
cussion and giving great stiffness to the whole
structure. The Warrior broadside, it will be re-
collected, is formed of 42in. iron and 18in. of teak,
and the new vessels of the Minotaur class of
451-in. iron and 9in. of teak. The weight of the
Warrior broadside per superficial foot is 3471 b., of
the Minotaur 3801 b., and of the target used by Mr.
Chalmers 369. b. The excess of weight of Mr. Chal-
mer's target over the Warrior is caused by the addi-
tional iron in the cellular webbing and back plating
and its lightness; as compared to the Minotaur
class, is due to the ribs at the back of all having less
lighter by nearly
target
tebbing between the
worka thirdto do,than a
tdhbeing h
f consequently
htherarmour ships yet
Was that its pecu-
lbivarilta.rralhlgeontheheotrhyf oaf
ctehlelatlaarr
teak and iron plate would obviate the evils that
generally result from a backing composed of wood
only, such as " buckling" and penetration, and
injurious effects
owfovuilhdragtui
ha
nr
wahgiacihn against equally hwettehqsuuael
hlyseverity upon the
fastening bolts. The plan of its construction had,
therefore, been calculated to disperse over a large
area the power or work that existed in the shot at
the moment of impact, so as to give a very large
surface of resistance by the time the concussion
reached the inner lining of the ship's frame. We
are bound to say that the result of the experiments
on Monday showed that Mr. Chalmers had not been
over-sanguine in the anticipations he expressed as
to the powers of resistence of his target. Though
exposed for some hours to a very severe battering
from guns of all kinds, it withstood the attack better
than any target of the same comparative thickness
that has yet been tried, not even excepting the first
and most famous target of all---that of the Warrior.

The trial to which this target was subjected was
precisely similar to that heavy ordeal which the
Warrior target had to go through on the occasion of
its debut at Shoebury. The number of rounds
fired, the guns, charges, and 'missiles were pre-
cisely tEe same on both occasions; but, es the tar-
get of Mr. Chalmers tried on Monday was nearly
one-third smaller than that of the Warrior, the
experiment was .obviously more severe fors the
smaller target, is the fire had tg be more concen-
trated. The expel invents were to have commenced
at half-pest ten in the morning, and all was
ready at that time, but the wilful obstinacy of the
crews of two small boats, who, in spite of some ad-
monitory 121 b. shots, addressed to them from the
shore, persisted in keeping in the line of fire till
nearly 2 o'clock in the day, prevented anything being
done. In fact, the whole day was very nearly being
lest from this circumstance. It would be needless
iteration to particularise the varied effects of all the
27 shots fired, when the experiments did at last
commence. Suffice it, therefore, to say that the trials
were gradually progressive in their attacking force
from low charges, and shells filled with sand, up to
solid 68-pounders, fired with the full service charges;
200-pounder solid cast-iron Act fired with low
charges, then fired in salvoes of three at a time ;
and, lastly, simultaneous salvces of three 110-
pounders and two 68-pouuders fired with full charges
and solid shot. The live shell and shell filled with
sand, as usual, effected very little, nor did the 110-
pounder with 101 b. charge, nor the 200 pounder with
a 101 b, charge do much more. The lower armour-
plate of the three which composed the target was
decidedly inferior to the two upper ones, and cracked
badly early in the day. This, however, so obviously
arose from a merely local defect as to be of no ac.
count in estimating the generalmerits of the target's
method of construction. That these merits were
neither few nor unimportant was soon seen. The
method of fastening on the plates by 21in bolts, with
stepped conical heads and a square thread, contrary
to general expectation, seemed to work admirably.
Partly from the resistance offered by these bolts,
and partly from the force of the concussion itself
being so deadened and distributed, there was very
little buckling out of the ends of the plates when
struck even by the heaviest missiles. The dints in
the armour plates made by the shot varied accord-
ing to the weight of the projectile when rifled, and
in no case were much to speak of. The 68-pounder,
as usual, left a severe mark, in some instances nearly
three inches deep. The salvoes of the two 68-poun-
ders and three 110's were a severe trial. The five
shots were concentrated on one spot, and struck
with a terrific crash, splintering themselves to frag-
ments, which went screaming back through the
air in all directions. The main side of the backing
—the skin of the ship, in fact—had, up to this time,
been carefully examined after each discharge; for
on the integrity of that under any fire depended, in
fact, the success of the construction of the target.
sign
irgi ot
rivet-heads eads ( which, in
yielding. Some
Itthree had,
o or
however,
four
o f
truth, were made too small) had been jumped off,
with one or two small belts, and there was a just
perceptible deflection of one or two ribs where
great strains bad come, but this wasall. The armour
bolts all held firm, and the back of the target
showed no sign that it had ever been fired at. It
was thought certain that the tremendous salvo we
have spoken of would altogether change this state
of things, but it did not. One of the armour bolts
was struck and the held knocked off at the back,
and the ribs gave tokens of distress, but beyond
this it was perfectly astonishing to see how well the
target withstood the five ponderous missiles. The
worst and mcst dangerous parts of the programme
had been borne by the target with impunity, and
as it was wished to see how the backing would
break, if it could be broken, Mr. Chalmers was
asked to permit the 300-pounder rifled Armstrong,
loaded with its formidable steel shot, to be used
against it. To this trial Mr. Chalmers in the
frankest manner at once consented, though he was
as well aware as all others on the ground that by so
doing he authorized the destruction of his target.
The 300-pounder was accordingly loaded with a
451 b. charge, and, as a matter of course, sent its
projectile completely through the target, leaving a
large and ragged hole, though not nearly so ragged
as the same shot would have made in passing
through armour plates backed up by teak in the
common fashion.

This fieqtructive shot brought the experiments

to a close for the present, the result of them being
undoubtedly in favour of Mr. Chalmers's system of
backing the plates, which is much superior to the
plans adopted either with the Warrior class of
vessels built, or the Minotaur class now building.
Both Mr. Chalmers, however, and all the cffic2rs on
the ground were of opinion at the close of the day
that a slight alteration in the combination of the
wood and iron in the target would make its power
of rc sistancestill more fen midable than it had already
shown itself to be. This alteration consists in reduc-
ing the thickness of the iron plate between the
beams of tenk by three-quarters of an inch, and
adding the metal thus gained to a 31in, external
plate, so as to bring the Litter up to 41in. in thick-
ness. Such a change, it is confidently expected,
would, withcut adding at all to the weight of the
target, add nearly 25 or even 30 per cent. to its powers
of resistance. At all events, it is conclusively estab-
lished that Mr. Chalmers's system of backing ar-
mour is one which requires to be attentively consi-
dered and examined with a view to the construction
of future ironclads. It is lighter than the new iron
frigate now building, it has been proved to be
stronger, and its inventor claims that it is nearly 25
per cent. cheaper. The lightness and cheapness are,
of course, most important considerations, which
when superadded to the all-important one of in-
creased strength speak loudly in favour of a careful
trial of the new plan.

The public who peruse these accounts cf what
takes place at Shoeburyness may, perhaps, ask how
it is that five and six inch armour plates are found
so difficult to pierce with the most formidable Eng-
lish artillery fired at pointblank range, when almost
every mail that comes to us from the West brings
dismal records of how the Federal ironclads fighting
batteries at long range have had their 52in. and
filin. iron turrets riddled like sieves. A few words
will suffice to explain this apparent anomaly, and
also enable our readers to understand how it was
that the Federal armour-ships got so lamentably
mauled at Charleston. The fact is that the plates
used on the Federal gunboats are not solid iron
—that is to say, not a single plate, but are built
up to whatever thickness is required by bolting
together separate plates of an inch thickness.
The vessel thus plated has all the weight of the
metal to carry, and receives scarcely any pro-
tection from the metal in return. A 5 inch armour-
plate thus built up is no match in power of resist-
ance for a single solid plate of two inches. In the
English navy all the plates are solid, and the vessels
of the Minotaur class, coated with 51 inches of solid
metal, have been proved by actual test to be in-
finitely stronger than the Federal boats, some of
which have their turrets coated with so-called 15-
inch plates. It is almost needless to say that no
guns yet exists capable of sending its shot through
15 inches of solid well-made iron.

Naval and Military Intelligence.

THE NAVY.

The Royal Oak, 35, 800-horse power, was com-
missioned at Chatham on Monday by Capt. Frede-
rick A. Campbell (September 13, 1854), formerly of
the Neptune, 78, 500-horse power. The whole of the
mechanics and artisans, several hundred in number,
who have been employed on the Royal Oak ever
since she has been undocked, quitted the vessel yes-
terday, and the only hands now engaged on board
are a few labourers from the dockyard, and men
frcm the steam reserve, who are employed in clean-
ing the ship before the crew joins. The Royal Oak
is to have a complement of 650 officers and men,
including Royal Marines and Marine Artillery.
Her crew, the greater part of whom have been for
some time quartered at the Naval Barracks, will
join to morrow. There is still a deal remaining to
be done on board in the way of getting the ship
ready for sea, and there is little probability of her
quitting Chatham for at least a month to come. She
has zaqt yet.takcnAlk. Ward -her armament, which
will consist of-t 1 of the ITO/poundnr:nivalArrel-.:
strong guns, and 24 of the.6B pounder, smooth-bore,
cast-iron guns, each of 95ewt. She will carry her
entire armament on her main deck, with the excep-
tion of three of her pivot Armstroegs, which will
be placed on her fighting deck.
The iron screw frigate Tamar, 3, 500 horse power,
which is ordered to be sent to Chatham dockyard
from the private establishment on the Thames at
which she has been built, is to be fitted to accom-
modate 900 troops, 80 officers, and a crew of 220
men. She is to be used exclusively as a troopship.
The Revenge, 78, screw line-of-battle ship, Cipt.
C. Fellowes, bearing the flag of Rear-Admiral R.
Smart, K.H., nailed from Spithead, late on Monday
evening, for the Mediterranean. On arriving at
Malta Rear-Admiral Smart will hoist his flag as a
vice-admiral on board the Marlborough, screw
three-decker, as the successor of Vice-Admiral Sir W.
Martin in the Mediterranean command. Rear-
Admiral Hastings R. Yelverton, C. 8,, will hoist
his flag on board the Revenge, as second in com-
mand in the Mediterranean, vice Rear-Mmiral
S. C. Dacres, C,8., appointed to the Channel deet.
The following is an extract from a private letter
rezeived from her Majesty's screw gunvessel Cygnet,
Commander De Kantzow, dated at the Havanna!),
March 4 ;—" Last week we were cruising in the old
Bahamas Channel, when two Federal men-of-war
joined company, one firing a blank gun and the
other a shotted gun across our bows. The com-
mander immediately went on board and demanded
an apology, which was given. We have been cruis-
ing in the same quarter for the past seven months,
but have taken no prizes yet. We, however, sal_
vaged a ship, and were awarded Xl,OOO for our ser-
vices,"
A naval courtmartial assembled yesterday on
board her Majesty's ship Victory at Portsmouth for
the trial of Mr. George Green, chief engineer of
her Majesty's steam vessel Geyser, on charges of
drunkenness. The prisoner, who had 23 years'
service, pleaded guilty, and the Court sentenced
him to be dismissed from her Majesty's service.
The screw three-decker Duke of Wellington is
ordered to be commissioned by Capt. John Seccombe,
at Portsmouth, es a depot ship', for seamen, in lieu
of the present depot ship, the screw two-decker
Hannibal.

The paddle steam sloop Geyser sailed from Ports-
mouth yesterday with a detachment of Royal Marine
Artillery and Light Infantry for Devonport, for
service on board the screw frigate Liverpool, com-
missioned at that port by Capt. R. Lambert.
Capt. H. E. Edgell, C. 8., has been appointed
Superintendent of the Royal Clarence Yard, vacant
by the promotion of Capt. the Hon. G. Fowler
Hastings, C.B.
Capt. T. Fisher is to receive the Captain's good
service pension, at the disposal of the First Lord of
the Admiralty by the promotion of Capt. the Hon.
G. F. Hastings, C. 8., to flag rank.
Capt. Alfred P. Ryder, private secretary to the
Duke of Somerset, was yesterday appointed to the
office of Controller-General of the Coast Guard, i
the room of Capt. the Hon. Swynfen T. Carnegie,
C. 8., promoted to flag rank. Capt. H. Hall, late
of her Majesty's ship Termigant, succeedsCaptain
Ryder as private secretary to the First Lord.
The following appointments were made yester-
day at the Admiralty :—Cspt. J. O. Johnson, to the
Pembroke, vice Capt. Fisher; Commander A'fred
J. Chatfield, to the Shannon ; Commander W. H.
Annesley, to the Liverpool ; Lieut. C. N. Iloare, to
the Liverpool ; C. Campbell, Arthur W. Brabrzon
Archibald W. Hamilton, Cecil G. Horne, G.
Mansel, and J. H. T. Chowno, midshipman, to the
Royal Oak; Henry M. Speer, Burg., to the Liverpool;
J. Trimble, assist.-surg., to the Liverpool ; Dr. F.
A. P. Heins, acting assist.-surg., to the Liverpool;
J. Roberts (a), acting chief engineer, to the Orontes ;
w. C. Beck, engineer, to the Cambridge,i for the
Redwing; F. H.Hermann, engineer, tindu
oties
f
3. Blight, acting engineer, to the
Gleaner ; J. Ambler and T, Carline, Indus, for the
Gleaner