The Portland daily press. [volume] (Portland, Me.) 1862-1921, 1866-09-27

the cleveland OOutCu0AOh1 ICNtcW vi Tile
Portland markets for the week, the shipping
news of the week, the late important news
from Mexico, &C., &C.
An ironclad feet is costly plaything. The
American navy now counts seventy of these
hard-shelled monsters. The monitor built
here cost 81 100000, while the Dictator cost
S5OOO,OOO, and the total expenditure for YES
sells OF this class amounts to not less than
S15OOO0O00. An iron ship depreciates in
salt water 10 per cent. annually. A years I'M
interrupted service of our whole ironclad
feet would cost us at least $l6,OOOOOO.
If properly housed and painted, and ex-
posed only to the action of the air, the an
nual depreciation is reduced to 1-2 per cent,
which is the least we can expect to pay at
present for such assurance of peace as is af-
forded by manifest ability to protect ourselves
against any navy which floats The premium
is rather high, but that is true of war risks
generally.
1t follows from these considerations, that
wherever our feetis placed it must be landed
high and dry, housed and painted Fresh wa
ter docks will not answer the purpose. Some
where, and perhaps at different stations, there
must be dry docks on a scale to admit of land
ing the entire feet, and not only of landing
but OF launching it again on short notice
The simplest form of dry dock now in use, is
that In which vessel floats into the dock and
is left, after exhausting the water, upon bed
at the bottom. These docks however are OBJ
viously suited only to temporary use for re-
pairs. In sectional docks, the vessel is float
ed over frame upon which it is then raised
by screws. This method involves great ex-
pense, requires the application of great me-
chanical power and exposes the vessel to much
risk OF injury from the unequal operation of
the screws. 1t is besides too slow to answer
the purpose. A third method of raising YES
sells for repairs is by means of floating docks
which are filled with water and submerged
under the vessel and rise to the surface when
the water is exhausted. Either of these meth
DDS, even il otherwise unexceptionable, would
require separate apparatus for each vessel
The expense Of raising one of our ironclads
would be multiplied by seventy as the feet
stands.
There must be some way of meeting this OBJ
lection. Besides the methods already named,
there is the marine railway, an inclined plane
upon which vessels are drawn up by the APP
plication of enormous force and upon which
their hulls and rigging are not unfrequently
racked and strained very seriously. 1t is by
some extension and Improvement of the prin-
ciple of the marine railway, one would think,
that single dock might answer the purpose
of landing perhaps even the whole American
navy. That was the thought which occurred
to our fellow-citizens, Messrs. ]. w. Munger
and W. o. Jones. 1t has been elaborated and
submitted to the examiners at the Patent
Office, and recognized as "a new aud useful
improvement in dry DOCKS" 1t is claimed
that by this method, the whole American
navy might be expeditiously and safely
raised from the water and launched;
died off upon dry land upon level faiIway;
and launched upon call within a few hours at
most. 4
vi ohO 0Ctduo Vi buiS c0uLTlVauCG
we can give no adequate notion. Its general
character however is easily ineligible. 1t
consists of a circular basin of any diameter
which may be preferred, with channel COM
municating with the sea and main dock di-
rectly opposite the channel. The vessel Is to
be raised, after the gates are closed, by intro
ducing more water, to such height that she
will float into the main dock where she lies
directly over cradle which in turn rests up
on a level tram-way and moves on wheels.
After the water Is exhausted and the vessel is
in position upon the cradle, she is drawn off
in line with her keel till she is clear of the
dock. The cradle will then rest upon num-
Der of carriages, over which the main track
runs, these carriages themsalvae resting upon
lower tracks at right angles with the .ck, and
the ship may then be removed to any desired
position leaving the dock clear for further
use. au,..H uFA stt f.is.f
II this were all, the capacity of the dock
would evidently be very much greater than
any continuance now in use affords. Its al
most illimitable capacity arises from the fact
that the main dock which we have described
is only one of system of docks radiating
from the central basin, which answers as
kind of turn-table and may easily be made
large enough to admit half dozen ships at
once. The number of vessels which can be
rolled off on the side tracks of half dozen
railways will plainly be limited only by the
extent of available surface in the neiehbor-
hood. t.-4
Is the invention practicable? That remains
to be seen. Ii vessels can be raised by water
and moved on an even keel to a convenient
position for housing or repairing, no words
are needed to prove the importance of the re-
suit. Ii that result can be accomplished with
less delay, as well as less risk, than is incur
red by the present methods, the invention is
one of the utmost consequence. There is no
insuperable difficulty in the matter of con-
struction. With stone and iron the thing can
be done, and the requisite power for moving
the carriages can easily be provided.
There remains only the question OF expense.
Beyond doubt such structure would be
very costly. As a government work however,
when compared with the cost and the annual
loss upon our irOnclad navy, the highest prob
aoie cost shrinks to insignifcance. Three
fourtns OF the annual depreciation of our
iron ships-and the saving by this method is
so estimated by one Of the best engir.
GERS in the service-would build .,oh
dock yard every year. For tho ,,.o
Of our commercial marine, the method
might be made available. The basin and Ia
docks might be dispensed with. A sino,s
dock, with the system of railways, would an
swer every purpose. In locations like that Sc
lected by the Portland DRY Dock Cornpany