5761. NAVY, Dockyards for.—[further continued].
While I was at Washington,
in the administration of the government,
Congress was much divided in opinion
on the subject of a navy, a part of them wishing
to go extensively into the preparation of a
fleet, another part opposed to it, on the objection
that the repairs and preservation of a ship,
even idle in harbor, in ten or twelve years,
amount to her original cost. It has been estimated
in England, that if they could be sure
of peace a dozen years it would be cheaper for
them to burn their fleet, and build a new one
when wanting, than to keep the old one in
repair during that term. I learnt that, in
Venice, there were then ships, lying on their
original stocks, ready for launching at any
moment, which had been so for eighty years,
and were still in a state of perfect preservation;
and that this was effected by disposing
of them in docks pumped dry, and kept so by
constant pumping. It occurred to me that
this expense of constant pumping might be
saved by combining a lock with the common
wet dock, wherever there was a running stream
of water, the bed of which, within a reasonable
distance, was of sufficient height above the
high-water level of the harbor. This was the
case at the navy yard, on the Eastern Branch
at Washington, the high-water line of which
was seventy-eight feet lower than the ground
on which the Capitol stands, and to which it
was found that the water of the Tiber Creek
could be brought for watering the city. My
proposition then was as follows: Let a b be
the high-water level of the harbor, and the vessel
to be laid up draw eighteen feet of water.
Make a chamber A twenty feet deep below
high-water and twenty feet high above it as
c d e f, and at the upper end make another
chamber, B,
the bottom of which should be in the high-water
level, and the tops twenty feet above
that. g h is the water of the Tiber. When
the vessel is to be introduced, open the gate at
c b a. The tide water rises in the chamber A
to the level b i, and floats the vessel in with it.
Shut the gate c b d and open that of f i. The
water of the Tiber fills both chambers to the
level c f g, and the vessel floats into the chamber
B; then opening both gates c b d and f i,
the water flows out, and the vessel settles down
on the stays previously prepared at the bottom
i h to receive her. The gate at g h must
of course be closed, and the water of the
feeding stream be diverted elsewhere. The
chamber B is to have a roof over it of the construction
of that over the meal market at Paris,
except that that is hemispherical, this semi-cylindrical.
For this construction see Delenne's
Architecture, whose invention it was.
The diameter of the dome of the meal market
is considerably over one hundred feet. It will
be seen at once that instead of making the
chamber B of sufficient width and length for a
single vessel only, it may be widened to whatever
span the semi-circular framing of the
roof can be trusted, and to whatever length
you please, so as to admit two or more vessels
in breadth, and as many in length as the localities
render expedient. I had a model of
this lock-dock made and exhibited in the President's
house during the session of Congress at
which it was proposed. But the advocates for
a navy did not fancy it, and those opposed to
the building of ships altogether, were equally
indisposed to provide protection for them.
Ridicule was also resorted to, the ordinary
substitute for reason, when that fails, and
the proposition was passed over. I then
thought and still think the measure wise, to
have a proper number of vessels always ready
to be launched, with nothing unfinished about
them except the planting their masts, which
must of necessity be omitted, to be brought
under a roof. Having no view in this proposition
but to combine for the public a provision
for defence, with economy in its preservation,
I have thought no more of it since. And if
any of my ideas anticipated yours, you are welcome
to appropriate them to yourself, without
objection on my part.—
To Lewis M. Wiss. Washington ed. vii, 419.
(M.
1825)
