The pilot and transcript. [volume] (Baltimore, Md.) 1840-1841, 1840-12-04
THE PILOT.
From the N. Y. Star.
NATIONAL VESSELS.


cation. 1t is from highly intelligent and res
ponsible source corrects some the errors of
the Boston press, and furnishes soue valuable
information as to ship building, and particularly
with regard to several of the prominent vessels
of our Navy.
The Boston Mercantile Journal OF the 18th
| inst. contains some remarks on the slooP OF war
Boston, now ready for sea in the harbor Of New
York. The worthy editor, who by the by is an
excellent scamen, says ga clean run is important
''where fast sailing is desirable; but does not
! seseem to be considered such by the chief con-
'estructor. BY not attending to tins point, many
s'fine ships belonging to the Government have
| sebeen spoiled"
The editor is wrong in his conclusion The
| chief constructor holds the doctrine OF a clean
run to be correct and he has always practised on
that principle. His ships among the sharpest
below in what is usually called the run, and he
considers indispensable to fast sailing and quick
working, and he also considers that great capac-
ity at the load floating line is essential TO hydro
dynamical stability. In support Of this doctrine
| shall quote the writings of distinguished math-
| maticlans and naval architects in Europe, such
men as Charles Dupin, Atwood, aud Admiral
Chapman, the celebrated Swedish constructor.
list. GA deficiency in stability is frequently of
the most serious consequences. 1t may cause
a ship in stiff breeze when engaged with an
enemy from using her lee guRs"
3D. 'sLe Scipion, lie Herbule. LIE Pluton,
! French ship of the line, instances of the
want DISABILITY, Alterations in the distribution
of the ballast were made, additional quantities
put on board; but no increase of stability was
gained by these arrangements, and it was only
by doubling them with light wood to the thick
ness of foot 1T the extreme breadth, and ten
feet under water, decreasing to four inches
length and dePthways, which corrected the defect.
Here it evident that the defect of instability
was not so much owing % a want Of extreme
breadth; but in diminishing the breadth at the
place vi fioatation too quickly fore and aft" To
this case may be added more recent one in the
Caledonia, British three deck ship.
Sd. ''The form of the immersed body, and the
weight of the ship are the chief terms in the
composition Of stability, and they only to be
attained in the requisite degree by full dimen-
sions near the lead water line, with sufficient
capacity"
A. "The load water section is the most impor-
tant element IN the whole construction, because
the stability of ship depends principally upon !"
3. "The most easy and advanta gcous way of
obtaining stability, is by large of fota-
ton, and great fullness between wind aud wa
ter; or which is the same thing, by keeping the
centre of the gravity of the displacement at as
short distance as possible below the waters sur
face. The old Hetion long entertained by con
structors Of ships that fiat floor gives stability,
led them of course to increase the breadth Of ships
as much as possible at the floor, or at the great
est depth below the surface of the water In
conformity with htwood's demonstrations ships
ought to be, for the sake of stability, made a:
broad possible at and near the waters sur
face, and they must consequently be made less
broad at the floor 1t will now be shown that
great breadth at the depth of the floor is'calcu-
rd fhe off ba Al.
an increase of breadth and just below the waters
surface"
g. ''That particular form, however. for fast
sailing ship, which the present state If our
knowledge would lead us to adopt as the best
calculated fast sailing is that which is deter
mined by making as large an arena of fotation,
and much rise in the floor, as can BIZ admitted
or in word, it is that form in which the centre
of gravity ofthe displacement is at the least dis
lance below the waters surface.
Z. awe must also increase the arena Of the
load water section to ensure a sufficient de-
gree OF stability. 1t is necessary to place the
centre OF gravity of the displacement at the least
possible distance below the surface of the water
in order to obtain the maximum OF stability and
the fastest rate of sailing.
8. "Increasing the breadth of a ship within
the limits of the parts immersed and emerged by
inclination, certainly adds to the stability, and
has been found beneficial in many instances and
may probably be tried with advantage in many
others"
1t was in accordance with the principles here
laid down, that the Franklin, the Boston, and
their sister ships, and the frigate Macedonian,
have been constructed.
The character of the ships indicate the cor
rectness OF the principle, and the validity of it,
cannot now be impaired by the mere opinions OF
any person.
Some there are, who, seeing ship capacious
in her after part at and above the load water
line, may suppose enormously that this fullness
extends to the keel. One test of a vessels form
is the launching draft of water, and the ships
constructed by the chief architect drew greater
difference Of draft OF water at the time of launch
ing than any ships of their class in the navy.
The act of Congress for building ten slooPs,
gave an opportunity to three constructors to try
a their skill. The ships were to be of the same
y dimensions, and to have light draft of water
The chief constructor, then attached to the Navy
!, Yard at Philadelphia, gave the drawings and
!, moulds for the Boston. This ship on her first
: cruise gave such ample proof OF excellence, and
> combined the qualities of fast sailing, quick
working, capacity and stability, to SO great a
;, degree, that the Navy Commissioners gave di-
rectiohs for the remaining sleops TO be built, to
I be OF her model, and frames were provided for
them, excepting the Falmouth. There was not
a whisper at this time against the Boston, moth
ing of excessive fullness: but when fifteen years
had elapsed, it was discovered that this ship and
o her sisters had not clean run, and that such a
form was not considered an important requisite
by the chief constructor. 1t is well remembered
that the Boston papers of that day, spoke in
terms of commentator of this vessel, which /
recommend to the special attention OF the editor
: of the Journal
The launching draft Of water of the ten
soops, excepting the Falmouth, is here sub
Joined, and from this statement it will be seen
; whether the remark OF the editor OF the Journal
was correct or not Perhaps he can furnish the
1 draft of water Of the Falmouth?
. The launching draft ofwater OF the
Boston,
$ Vincennes,
2 Fairfield, 80. - to.,.xa q
h st. Louis, was AT 49,, iSn. r. q i,
! Concord, IT, IN