, 1862-02-11
THE ATLANTIC MORTAR FLEET.
Commander POrter14 EXped1.
t1Ou.
DESCRIPTION OF TIE N0RTlRS ANp
VESSELS,

Commander TorteF's mortar hottlla is rap
idly preparing for sea. a large part Of the
vessels Of the fleet have received their tormld-
able armament, and have started for the ren-
dezyous at the South or are ready to sail.
Tile plans for this expedition were formed
several months ago, but the novel character !
of the enterprise has necessarily retarded the /
arrangements. Elaborate experiments have |
heavy mortars with which tic feet is armed, |
and the equipment Of the vessels has been
work Of time. At intervals the public have |
been aprrised Of the progress Of the work be-
slowed upon the expedition at the Brooklyn /
Nsvy Yard, but no complete account has been |
given Of the character Of the armament, or the I
objects which the fleet Is intended TO serve: |
The subj0ined statements furnish 3 history OF
tue movement:
THE MonrARs.
The twenty heavy mortars which form the
principal armament Of tho feet were cast at |
Pittshu5g, md arc Of immense e11s!,,t SIG e aud
seventeen thousand pounds, or eight and a
half tous-almost equal to the weight Of the
ten-Incl columbiads, which arc nearly three
times the length Of the mortars. The dame
ter of the bore is thirteen inches. The total
depth of the bore is thlrty-fve inches-a little
more than two and half times its diameter.
But the most remarkable feature in their COZ
6truction is the thickness of metal around the
bore, which is at every point no less than fifteen
inches. The trunnions measure fifteen inches
in diameter The entire length Of the mortar
is fifty inches, and the aggregate diameter
forty-tlrce inches, or more than three and 4
half feet.
Ordinary mortars are quite tight, compared
with their ca1ibre. Those Of English manu-
facturc, Of thirteen-iucA bore, weigh from two
tons Qand serVice} to five tons and 4 fraction,
{the heaviest sea coast mortars.) Those with
which Commodore Porter's vessels are pro-
vided-which may be used nike for sea and
land sers1cc--are about double the weight and
strength Of the "approred" English morta1s,
tively small charges Of powder were used and
and short ranges obtained.
Commodore Pofter's mortar6 arc elevated
or depressed by mt ans Of cog-likc projections
on the breach, into which lever fits, support
| ed By the frame work OF the carriage. By
means Of the accurate working Of the reyolg-
ing platform and The carriage, ranges can
easily be obtained It is believed that accu-
rate firing may be made ut L distance Of two
| and q quarter miles.
! The force Of the recoil Of these mortars,
when the full charge Of powder allowed, -four
teen pounds,) is stated to be seyenty-ive tons.
/ THE MORTAR VESSELS.
Tic vessels Of the mortar fleet number
| twenty-one, and, with the exception Of the
| flagship, are sailing vessels. Nearly Ill Of
I these are schooncrs Of two to three hundred
tons burtben. Originally they. were fitted ont
Stctmcrs cannot he adyantageously employed,
the ponlerous nlortars necessarily occupying
the centre Of the vessel, SO that tic position
usually assigned the engines Or machinery
| Of 4 steamer is taken up. Besides, these small
ger ones; their light draft fitting them for the
navigation Of shallow Eaters, and their small
tonnage requiring comparatively few men to
manage them. Moreover, as mortar vessel
fights best ut anchor, facility Of movement is
unnecessary
Tie adaptation Of these schooners to the
mortar service is admirable. An almost solid
mass Of wood las been built from the keel to
the upper deck. This staunch groundwork is
composed Of tinlbers over one foot square,
and twelve feet ir length, interlaced and firmly
per deck the "bed" is built, consisting Of {
:. solid horizontal surface, circular in form
with "trlck !" near its edge, upon Which rur
rollers bearihg q revolving platform. TIL
) great mortar-bed is carefully braced, end sup
ported by the cntirc strength Of the vessel
design is apparently perfect
: THE REVOLVING PLATFORM
The circular platform surmountins the bel
. / and bearing the mortar carriage is constructed
Of heavy tinlbers, and is one foot in depth ant
: | nearly twelve feet in dia1neter. When il
. position for a discharge, it lies flat and trml
| Oh its bed, but by ingenius mechanism it ma
/ ~. r. any a;rc1t;os' ~ - ras;tr1,t # II ~
vazsc1 s13;fts is nos3tinn.
r.. ,hanoa ~ i1;racfion is cas;,v and onic1-,
,,eoror'si,SG - " ~ n,aons oT fo,r ~ aceante;
ay1cs In the ,,1a, firm to which LAYERS ar
I 1;fic1 the 1nort.r and' nnochiucrr f1eil1,;n
n,-cr ~, - tonsI mar hn roiscd and +hn W.;rl
: Transferred hy t1,c same nooSemeut to a sTe:
nnnrsr ~ ,E5..,1iic ro1orc .,rta1hnd n - Fan,
~ r. ~
. TIen 1,e means of tSct1c n1reai;v nrT.,,,,rci
$ ~ n1oi, n.ass n1nr - 7nouu5 ~ ;ts d.s2r,.
nns;tiIn, and instapt1v nv y rcrrrsc my,
; n3nnnt rcnIace;7 IN the led In fie cc,1frc +
= lie 11atioTn,. and estenlinr Into tic sol
mnss hcncat1, IL an iron cy3n;3er ar snind1
= when 1,rercnfs any sii}e movement. The a
/ rangcnent Of this machinery is cxcecdingl
s simple, aud the invention is attributed to Or
Of Tic lie,ttenants Of the navy, now active
d engaged in the preparation Of the mortar re
l. scls for tI4eir work.
y TIE MORTAR CARRIAGE.
! n,, 80. ;. - ea'.s..ss.oa a7,.o
~ G.'t "a soa@ IetsI ~ o.1o LILY
~ cAc!usnGS " Ntousnt 1 Eon- ~ MnStn u
aoous nne iGet anu !. ~ 1 ~. anu % Mins4 ~ ~
t9tt 1ee. ~ lot IT. 1eis 1s anJ ~ ~
le ~ ;nn ~ .aaei I aad i,a.,;
Eac3a xet ~ rae4;n. ~, t1o,, a'u ..,am
le p,ortari is aisc1,arscd Tho curriare ia en-
II posed principally Of plate iron, Tivetted t
Is gether, braccd and bolted. It is 4 Game-wo
@ Of excellent design, and, though Weighl
n probably not more than two tons, is capaf
u Of resisting pressure Of one to two 1undr
~ tons.
n Two wheels are set close to tic ffame-wo
n directly under the mortars; aud connect
n with them are eccentric ax1es, SO arranged
~ ~ to permit SO large part OF the weight to
el thrown on the wheels, that the carriage m
III II is nnt intended however that the rec
ut ef the 1nors.r shall in any dcrrcc hn taken
Ii or lcseened in its effect hv tiIc moy1n,r Df
he wheels Tbc corriasr 1ies firmly IN fhe nj
1k forn, 1rhcn tlc morfar is disn1oroc1 and i
to nn1r nnss;h1n motion vii f~ ti,at ~ tbe v~s
IS, in tf,d 1rafer ~ ~
r. 49, 'ANs TIT moving Avn po,xnrp
ed 49, DA'
al Inc bomDsheils 10 De thrown from lie II
re- lars are OF The ordinary description, Iese
tv oiiIsS fo1hd shot, pnt hohoW, anu "elgh
Of nnhncd over tWo hundred pounds cach,
.ce mosl 1oln1aaele ordnance u1 !nlsslies hnoMn
Hlooc1n @ LII maltase, T.; miIn dne sl9Gs "
ed ose use4 ~ tns aeat, oua1 a,, aaa "
y, tLousand Of these bombs have been furuis
VI for The f1nti1ta. and it is understood that
in- - . .nS ,1,n 49, ~ - 4naa, ss". -:
ILL., oan1, s1'o,1 3,e,r!. ~ 4o1s
lch su1ta 49,. I..sS NGn ~"
to 49,. ;,ssena 49, :" - ~7'''
ve- 1His pulpose.
ack OTHER ARMAMENT:
len In addition to the mortar armament c
ex- vessel Of the fleet has been provided with
7e- s:lons thirty-twos,'s Of tho best dcscripi
hat Of smooth-borc ordnance. Each of these we
md thirty-Eevcn hundred weight, aud thr
lgh round shot and shell, The vessels arc also
nm | ,.+dod -r;fb e-nrj- r,;1-oc o,,a ri ho- anoo