The Sun.
London, England, 1862-01-29 00:00:00

FAZIOAIRN'S PLAN FOR ARMOUR-CASED
SHIPS.

Mr. William Fairbairn, LL.D., F.R.S., has just com-
pleted for the Admiralty a target embodying the principles
which he considers will prove superior to those adopted in
any vessel yet constructed or commenced, for armour-cased
ships ; and in a few days it will be bent to Woolwich,
preparatory to being submitted to the same tests as were
applied to the target representing an actual section of the
Warrior's side. It is known to those who have paid at-
tention to the discussions on the subject, that Mr. Fair-
bairn holds that the more solid the backing given to
the armour plates, the greater will be the resistance
offered by the plates themselves, whether to the pene-
trating or crushing action of shot. The experiments with
the Warrior target were not altogether satisfactory ; and
others made about the same time, with single plates,
strongly confirmed Mr. Fairbairn's views. Thus, a single
plate was fixed against a slab of iron, another on a block of
granite, a third to 3ft. of solid oak, and a fourth to oak and
teak, with indiarubber between the plate and the timber.
The first was indented by the shot, bnt very slightly ; the
second suffered more, but still stood well ; the third
was penetrated and considerably bulged ; and into and
through the fourth, as well as a good deal of its backing,
the shot penetrated with ease. The law seemed to
be established, in fact, that in proportion to the in-
creased elasticity of the substance behind the plate, was the
decrease of the resistance of the plate itself.

Mr. Fairbairn proposes, therefore, to use nothing but
iron in the construction of vessels of war; and his opinions,
if verified, while not favourable to the plan adopted in
ships of the Warrior and Defence classes, and to be
adopted in the Achilles and others ordered, would amount
to a condemnation of such vessels as the Royal Oak,
Caledonia, &c., which are ordinary wood vessels protected
by armour plates. All of them are great improvements,
no doubt, over wooden vessels; but unless Mr. Fairbairn
is proved to be mistaken, none of them will equal, in
natural duration or in powers of resistance, vessels which
ought to be supplied as speedily as possible. The
Warrior, so far as she is armour-plated, has her sides
thus composed :—The armour plates, 41in. thick attached
to iron, forming a perfect skin, sin. thick, supported by
ribs of fin. iron, llin. deep, and the whole backed by 9in. of
oak and 9in. of teak. The bolts fastening the armour plates
pass through the timber as well as the iron skin, and, are
screwed inside; they are thus necessarily about 2ft. 3in.
long—a long bolt being comparatively a weak one. Her
plates are grooved into each other, and experiments have
proved that the grooves are points of weakness. Of course,
the weight of the plated portions of a ship is a matter of great
importance; and the Admiralty stipulated, before ordering
Mr. Fairbairn's new target, that it should not exceed, size
for size, the weight of that representing the side of the War-
rior. Increased weight might become a serious drawback
constructively; and it would not have allowed a fair coT.n-
parison of results arrived at experimentally. Mr. Fair-
bairn's target is 20ft by 10ft, and weighs 31 tons, of which
the armour plates represent one half ; a target of the same
size cut from the Warrior would weigh 32 tons. Four
plates, 4in thick are used—the upper and the lower being
each 20ft long and 3ft 4in deep; between them being two
plates 9ft long, separated so as to leave an opening equal to
a port hole of the Warrior. The plates are affixed by tin
bolts to lin iron representing the skin of the ship ; behind
it being ribs lin thick, with 4in angle-irons at each edge,
lin rivets being used in.fastening the angle -irons and affixing