Alexandria gazette. [volume] (Alexandria, D.C.) 1834-1974, 1858-02-17

is it's appearance ot strength. Its principal
dimensions are as follows
LangtL - tween perpendiculars~........".".....6sOf feet.
On
Extreme breadth of the hull ........."....... ~
" " across the padJe boxss..."""lS
Tonnage odd measurement. otonS'
The ground on which il was built was first
prepared for the purpose Of giving 1t the ut
cessary solid,ty to bear its weight evenly. oy
the driving OF upwards Of 400 piles. This
would seem no great plumber, unless the
ground possessed some good degree OF solidi-
" To begin with, for We believe that twice
that number were driven IN the foundations
Of the freight-aouse OF the Boston aud WOr-
cester K ilroad, which building, by the way,
il Just about equal 10 area 10 the famous
ship UpoG the ground thus prepared. a
level platform was laid h a height Of about
five feet, composed of ''balks of timber
Along the centre OF this platform was first
laid tie X el-piate. consisting OF plates OF
iron an inch thick, inserted together as they
were laid. u Jon this was lalt what Is call
ed the ''ceutre web" and which answers
sill btly u the ofic OF the keel Of an ord'-
nary ship. al: hough laid within the outer
cla;ing OF iron plate here belDg 10 TACT
no keel. Then on the top of the centre
wet" is laid auotber and inner coating Of
IRON plates, three quarter, Of an inch thick,
which j. kept at a distance of 2 feet 10 inches
from the outer coating. The plates Of the
outer coating, except at the keel. are also
threC-quarters of an inch in thickness. No
frame or ribs were erected to indicate the
shape of the growing structure, but 1t was
formed by the continual boltlng OF one iron
plate to another, both on the outer and inner
coating, or as il is called, skin" Of the ship
The shape OF each plate, before 1t was
brought to the spot, being exactly shaped 80
a. to preserve the proper form OF construc'
ton, both in the outer and inner sklo, which
were kept throughout at an equal distance
from each other. Every plate was p%erfors-
ted around each Of ITS edges With holes, vito
! such exactness as to receive tho bolts which
rlyet it to the next adjoining plate. The
average dimensions OF the plates are ~ ieet
10 length by 2 feet 9 inches in breGdth. The
number Of plates 10 the entire hull ~ about
10000, of an average weight Of nearly oOo
lbs, and the number Of rirets for fastening
them together, nearly 100000.
In addition the centre web" which
RUS the whole length Of The ship, and occu-
pies the ordinary pace of a keel, serves u
retain the outer and inner skins" al an
equal distance IF 2 feet 10 inches from each
otter. There are also 81 other similar
VETS" running the whole length Of the
ship, nearly parallel to this central one,
which divide the space lougi,udipally into
81 compartments. and these are Intercepted
at distances Of 90 feet by twelve bulk-hesds
running transverseiy ACROSS the ship, suodi-
yldIng not only the space hetw cen the TWO
skins" but also the whole lower art OF
the ship int It'll smaller compartments; 50
that il by any accident 10th the outer and
inner skins should be per Grated SO ~ t. sd-
init the water through them both, It's accsse
would be limited TO ono OF the Compartments,
8 that the safety of the ship would not be
endangered.
The process Of laying and rivettiug to-
gerher the two cOucentric surfaces OF iron
%piates, which Constitute the entire raising OF
the structure OF the ship, Is pert 'rmed WITH
great rapidlty-esch plate before It 10
brought upon the ground being shaped 10
such q pattern, and perforated Tor the bo'is
With such elaCtness, as to bring out the
skIlful!y designed outline, without any Ia
card vi error. This result 10, OF course,
produced by the previous study OF The eugI-
ncer. who FIRMS q model 10 wood VI each
plate of the eUtTe ship, hardly any two OF
which are Of the same form, and by this
model the iron plates Of al luch IN thickness
are cut by the huge steam shears, With as
much ease and more exactne-s than gal
mems are shaped hy Il paper pattern. Inc
rlat.s, when shaped aud perforated, are
brought ~ their position 10y appropriate ma
chiuer,. The first operator Ut a working
party adjusts ,he plate-:he bolts, at u yhise
heat, piaced 1t his side, are Inserted by him
ou- by one, from the inside Of the ship, and
while he holds them III sheir position, oy
mesus VI a heavy hammer ~ the head ot
the bolt, two strikers, by aIterLaIe blows,
rIvet the head on the other S de. The bolts
contract III cooling. and thereby draw the
plates together with q compsctuess that
could be sttaIned by no other force. A
other attendant keeps ~ the supply of heat
ed bolts FROM a furnace near al hand, as last
as they are required. 10 this way the ship
sttains lis dimensi ms by u gradual advance,
hardly observable from day TO day, without
the apparatus Ot massive frames or nachlL-
cry, the growing structure It-eli atordIng
the prir aIpal Suppo.t TO the necessary sca .
{ ljing aud working machinery, and IN due
time the same processes 10 the structure OF
the buIkheads To form the compartments
the other partitions. gahgxays, aud other
work, which contribute to the strength and
convenience OF the ship when finished, being
made to It's progress.
Il will be perceived that in describing the
structure vi these two concentrIc iron walls
Of the ship, with a " ater- light space between,
and with various subdivisions, we have been
describing the tubular principle OF giving
strength t. the whole frame OF the ship
here are, however, ,sriOas other work.
Snieu are inside 50 contribute ~ Der strength,
while they serve othsr purposes. This may
be said Of tho DECKS, the traDsverse bulk
beads, and particularly two parallel loogi
tudinsl Lulkhesds, IT iron walls, three hun
dred and fifty feet in lsngth, and thirty ssil
feet apart, which divide Tho whole ct The
ship below the second deck, into three psrts
1t is remarked ss a satisfactory proof OF ID.
suficiency Of the strength OF the Le,istbse