Weekly national intelligencer. [volume] (Washington [D.C.]) 1841-1869, 1846-10-31
IRON AND WOODEN STEAMSHIPS.


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IRON AND WOODEN STEAMSHIPS.
Comparative vieU of the relatire advantage OF
constructing Steamships Of ,oood or Of iron, ia
the United States, for ocean navigation.
By JuNIus SMITH, LII. ID.
From the natural position of the United States and the pc
cuar characteristics of the people, the science of marine
chectue, by inevitable consequence claims prominent
rank in the pursuits of knowledge and being closely
terwoven with all the great interests of the country its cu
vaon and practical application will continue to be, what it
has been subject of the deepest sociude Whether
consider it in relation the mercantile the naval marine
of the country it is equally important The experience of all
time before us and it remains to be how far the genius
of the people will discover improvements and add strength
beauty, velocity and durability to the naval and mercantile
force of the country.
gradual but uninterrupted extension open field for sci
enc labor, and stimulate the public mind to bold and
tried achievements That there should arise amidst the de-
veopmens of sangune minds much fancy and speculation,
and theory and costly experiments, upon theme and
comprehensive, is just what might be expected But
the failure of the most aterng antcipaons advances the
science ITSELF Our ideas corrected by being driven from
untenabe positions to others sound and practical The
best system ascened by experiment. and by experiment
only In this respect bears analogy to the science of
chemistry which has grown up step by step by slow but
certain advances, until the elementary principles full
y developed, and their application to the and
features has conferred ncacuabe benefits upon the family of
1t is worthy of remark that the fact of several iron
steamships having been constructed in England ground
for concluding supposng they succeeded that will be
equally advantageous build of iron the United States In
England iron cheap, and timber dear In this country tim
Der cheap, and dear The first of ship, there
FORE depends not upon the material itself with which
sucted but upon the price and facility of obtaining that
eral at the place of building In this country the of
iron built ship about thirty per than the
wooden built ship of the dimensions She ought
therefore, in order stand upon an equally advantageous
footing, reference the of
wooden-built ship to be kept in roPo oaorthy cond
ton at thirty per less expense and to maintain dura
biy of thirty per cent longer time than wooden built ship
short time has elapsed since the first construction of iron
steamers for navigation and far the result Of expe
men is by in favor of their durability compared
with tmber-buit ships.
The Monezuma, Mexican iron steamer constructed at
Woodside opposite Liverpool in England, New
fork together with the Guadaoupc years for repairs
The Montezuma had been in service abouth years When
in the hydraulic dry dock went examine her condition
found that between wind and water there was streak from
stem to stern, where cooson had taken effect and whole
line eaten in from l-6h 18th of inch resembling
oney-comb The cause of this effect sufficiently obvious
he motion OF the ship at alternately dipping and
merging and bringing the salt under the action of the
hot produces chemical decomposition Of the liquor
evapoatng the fresh water particles and concentrating the
ratio acid and thus forming powerful solvent, constantly
acting upon the iron plates 1t may further be observed
iron has strong affinity for muTac acid which rapidly dis
solves thin sheets of with which contact and
is forced by attraction and into the cavities of the
iron, exeeng the globues of air and assuming their place.
and thus breaking the strength of the iron Just proportion
the attraction OF aggregation is
II great effect be produced in three years by the
ton OF salt water upon the iron plates and the remaining
plates weakened in and similar the dry
rot in timber, the understanding find great difficulty in
measuring with tolerabe accuracy the durability Of the ship
Il will be borne in mind that the last stage of consumption is
far rapid than the FIRST because the disease has pene
ated the whole mass constitutional vigor prosated and
the living thing is already dead.
am that mode Of galvanizing sheeron has
Iao, ul.t lo(o..
thus rendering it an-corosve INDUCED Undoubtedly it
will check oxidation upon the body Of the plate but beautiful
the operation is fear the grand difficulty will remain
remedied Wherever hole is perforated for rvets, screws
or BOLTS there the plate already weakened in pro-
portion to the number and of the holes. The muriac
acid is invited and il begins feed upon and oxidate the
whole ship. There is mutual attachment, and they rush
into each others through space larger than hair
Another important result from the experiments that have
been made demands notice and that the mpossiblity
OF rendering ship constructed OF iron plates veed together
from two to three hundred feet in length the may be-
waterproof The rvets which faen the iron plates each
other to tho iron ribs of the ship the bearings which
are to sustain the varying and srainng of the ship
BY continual action, there being elastic medium between
the jennings Of the plates gradual though minute opening
sufficient for the admission of water made throughout the
ship; and apprehend this much be the there
other wearing by the motion of the ship than that upon
the rivets The drawing Of the head Of rve screw
bolt through plate, which have SEEM leak nc<
easily detected, and still loss easily remeded This ar
believe, will be confirmed by the experience of all TIE iron
steamers that have weathered the
The United States iron cutter, the Bcsre, which
examined when under repairs last year New DIRK, is
very eaky ship The openings Of her plates, at the bottom
Of her keel least half nch snd they extended
more less from stern, between each set OF plates
Wokmen employed in forcing lead into the openings
to stop the leaks process which, appeared to me, would
ultimately make the leaks than before. ship con-
suced Of timber cauked between every streak of plank
ing, from the keel the upper deck The aggregate Of this
caukinp thus distributed, constitutes elastic body of
siderable thickness which yields impecpby TO the heavng
and rolling of the ship, without opening admitting
water In case Of leak the ship easily fresh caulked and
all necessary repairs made with great facility But you
cauk iron built ship and from my observation,
perceive tb6t oxidation Of the iron plates both within and
without the ship, commences the they in
with salt water and, of course the chemical laboratory
is at work to effect eakages and the ultimate consumption of
the ship The repairs Of iron built ship far diff
cult and expensive and Intellectual than the repairs Of tim
Der built ship Few people work in iron almost every
sailor can work up wood The idea suggested by honor
able Senator, that non ships require repairs and will last
almost forever is entirely faacous and founded upon mls,a
ken data, or the want Of experience.
The formation Of lamina, thin scales upon sheet iron
when exposed TO the action Of salt water natural conse
quence, and become visible, particularly after having
been fresh painted The oil Of the paint oosens the oxdated
SCALE that pees off, leaving its original place upon the
plate untouched by the paint and ready for the repeated ac
hours after painting The abstraction Of every SCALE tits easy
to see, is diminution Of the strength Of the ship