The new South. [volume] (Port Royal, S.C.) 1862-1867, 1862-08-30
Iron Clad Frigates-Bending Armor
Plates, &c.
From the Scientific american.

being converted into an iron-ca,l turret war ship.
Snc is to be clothed amidships with thick iron
plates, which are to extend about five feet below
the water-line and she will have three great re-
volving gun turrets on deck, and powerful iron
beak or ram on her bow. This beak resembles
huge ak, and is formed of two plates, twenty feet
long, four and a half inches thick, thus making
nine inches of iron on the front edge. Each Of the
revolving gun ttrretS will be twenty feet inside
diameter, and the sides will be formed Of eleven
courses of inch iron plates.
These plates are laid over and riiveted to one
another in such u manner as 10 "break joints, .
and vertical plates also boted to Several courses
so as to secure the whole in the most rigid and
perfect manner. These gun towers Tor the Roam
Oke are now being constructed 1T the Novelty
Works, in this city, where the plates for them,
likewise those for the amor, are bent to the prop
or curves. Each plate for a turret is about nine
feet in length by forty inches in width, and an
inch in thickness. Two courses Of rivet holes arc
punched out in each, and they are all bent cold in
powerful hydraulic press The bed plate OF the
press is Of concave form, and the top block is of
a convex form.
A plate to be bent is placed upon the concave
bed plate Of the press, and when properly adjusted
the pump forces UP three rams under it, and the
plate is reduced to the proper curve against the
top block. The pressure to which each plate is
submitted to give it the proper curve, is three and
a half million pounds. BY this method of bending
the turret plates cod there is perfect uniformity
and accuracy secured for the whole. The turrcts
for the Roanoke will BE- of a superior character,
but only six courses ofpates have "a yet beea laid
on two of them.
The bending of the thick plates for the ram, and
also for the sides of the frigate is quite different
and difficult operation to perform, compared with
these of the gun-towers. Each Of these plates has
to be bent to the proper curve to suit its own par
tcular place Oh the vessel and not only the broad
side but the edges also must be bent to suit the
particular curves. The bending operations
under the charge Of Mr.. George Bonniwell, an in
telligent young shipwright. All these plates are
hammered iron, and are furnished by several COM
panies in Pennsylvania, New York and Massachu-
sets. When they arrive, they resemble huge
straight iron slabs, varying in length from eleven
to twenty-five feet, and in breadth, from twenty
two to twenty -four inches, and their average thick
ness is four and half inches. One Of eleven and
Il half feet length weighs about 4,240 lbs; one Of
twenty-five feet length, for the ram, weighs over
four tons. Such masses of iron are difficult to
move about, and the operations connected with
bending them are necessarily tedious and trouble
some; and they require great care and skill to
conduct properly. Of course it is impossible to
bend such masses of iron cold, hence each plate is
first heated to nearly white heat in a long fur
mace, shaped somewhat like bakers oven, with
movable arched cover. The press for bending
is quite different from the one used for the turret
plates. Outwardly it resembles long, strong
iron screw press, used for pressing wooen cloth.
Its top block, or platen, is moved up and down,
but its bed is fixed and very solid. A dudgeon
hydraulic jack at each end supports and moves the
block up and down. The bed, upon which the
heated plate is laid, is formed Of series Of adjus-
table bolster blocks, each Of which is capable of
being set by screw to any desired height on
either side, and at any desired angle to suit the
bend to be given to plate which is compressed
between the descending top-block and the adjusta.
BILE bed. Aplate is first placed in the furnace, and
it is then raised to nearly white heat. The cov-
now raised by block and tackle, and the plate
is then seized by powerful crane, secured on
carriage. The heated plate isnow lifted, the crane
and placed in the press, N where it is perfectly ad-
justed to obtain the proper curves. The huge
top-block is then forced down. squeezing the great
mass of iron into the desired shape.
In about half an hour the plate has acquired
permanent set, and it is taken out ready to have