New-York tribune., 1871-08-02
THE FERRY-BOATDISASTER
TIE EXPLOSION EXPLAINED.
HOW 1T OCCURRED-THE THEORY OF UNEQUAL
EXPANsION-oPINIoN OF AN ENGINEER.


EXPANsION-oPINIoN OF AN ENGINEER.
critical examination of the wreck OF the
Wested was made yesterday by wellnformed persons,
with view ascertanng informally as far possible the
cause OF the explosion Such an examination s due 10
the anxious pubc and in conducting 1t the present con-
dton OF the boiler and the position OF the fragments are
taken as guides. The explanation and description here
with appended throw light upon this painful sub
1t will he remembered that curled fragment of the
boiler, OF the shape Of rght-angled triangle, ana
weighing about so pounds was thrown upon the Barge
Office PLATFORM the east side Of the Westbeld failng
at distance OF about feet Most Of the fragments OF
the wreck fell on the same side Of the boat The pas
sengers also thrown into the water upon the east
side One of this propulsion to the east side IL at
in sheet Of boler-iron, about 81 feet wde
which lies extended. like piece Of carpet, from the
edge Of the boat the upper deck down to the lower
side Of the boiler This sheet the middle section OF
the boilers "shell," that is TO say, OF the
| boiler itself. At the upper end fragment
| has been torn away. This is clearly the piece
! which was picked up the Barge Office platform,
and which Is in safo-heeping at Police Headquar
ters Twelve from the upper end of the long strip
OF boiler, iron is round aperture, about 10 inches III
! diameter which led INTO the "man-hole," opening
into the boiler tho top IT, then, this section OF the
boiler were placed where IL plainly previous to the
explosion il would be seen that longitudinal DreaK
occurred the west side OF the boiler shel tls inc
boat stood at the andng), ABOUT IL Inches aoo'o 'c
level OF the lower de and near the level OF the BOTTOM
| of the lower range Of fues inside the boiler.
These points being settled and the careful examna-
ton leaves no doubt regard to them the present posi-
ons of severed parts of the boiler are readily ac
counted for The boiler shell" was 10 feet In diameter
and "A feet long The ues filed the lower half Of the
she'll each being about 90 inches in diameter and rest
ing in two tiers, four above and three be
low When the middle section OF the I" shell
gave way, the base OF the Doler, u
was instantly whrled, like ribbon borne by the wind,
but with terrific force, upward over the boiler ana
against side of the upper deck Its width OF about
Ss feet was ripped of the centcr OF the shell in dl
rect line along the course of the vets around the cir
eumference. As the end was flying upward, some OBJ
sace of iron strong wood was met by winch the tf-
angular fragment torn off and sent spinning with
accelerated velocity and in the same general direction
50 that il fell upon the Barge Office platform The boiler
/" shell 4" thus biseced inst1ntaneousiy ana
against its opposite ends pressing the tremendous
force OF to 35, perhaps more, pounds 10 the
square nchequa to the force Of several hurricanes com
bned The result that one-half OF the shell was
driven directly along the empty hold into the curve at
the stern Of the vessel where IL was stayed by the
strength OF the ribs OF the hull As lies wedged In,
and much indented, it looks like small gas holder rest
ing upon side. Tho other end OF the boiler contain
ing the furnace, ,was square, with "wagon-roOi" top,
and more massive and snrmOuntcd by the steam
chimney" which is about 10 feet high, and is simply an
extension of the boiler This end driven forward
distance of about feet, crushing its way through
15-nch beam and lodging against the great braces by
which the shaft of the wheels Is supported.
The dues were thus left almost entirely uncovered.
They were thrown diagonay to the west side, that
the end opposite rests several feet beyond the
keel line. This circumstance Ia demonstrated by the
fact rivetng of the she'll the cast side was
the last give way and that uggng effect was pro
dueed by the mOmentary cngng OF the half which was
driven into The edge at the line OF division
and 1arla aatfb fba eli
OF the boat, toward the stern, showing that
that half OF the shell touched the first and
glanced off, This circumstance serves also to confirm
the explanation that heorgnal break was on the west
side OF boiler which would tend 10 give quartering
direction opposite ends. The flying center section
of the shell gave the general direction to the east OF all
the flooring timbers and bodies above 1t the main deck
toward the stern hosed in the line OF the flight OF
the half Of the boiler the steam rushed ont, striking
first against side OF the hull and was then de-
feced to the east sweeping everything before it-up
ward into air whence all fell either into the water
or back hold Except the removal Of the lighter
rubbish the purpose Of recovering bodies no change
has been made in the positions Of things since the mo-
ment of the explosion
"UYEQUAL EXPANSION"
The opinion OF Norman Wizard, the engineer,
who examined the exploded boiler, Yesterday
with THE TRBUNEs representative is that the OF
the explosion was unequal expansion This is also
the published opinion OF James A. whitney, practical
engineer the result of whose investigation appears To
tally throughout with that of Mr. Wizard. The examina-
ton by Mr. Wizard was continued for several hours and
was based upon years study of the subject OF boiler
explosions. His theories as follows
Boilers most commonly fractured longitudnally
the line fracture being about that OF The water
for that which Ia remains at the top. Steam.
on the other hand absorbs heat more rapidly than any
almost always immense difference between me neat
of the steam and the water below II. Inc eoer1T3n iron
nf
result is unequal expansion and In case OF oscillation or
other of change OF relative positions fracture O
bers The in the boilers, beneath the lower RANGE
ues is comparatively COOL or say ~ 50 Wnle ABOVE
the temperature of the ermay be 800 and OF the steam
much greater Hence the boiler shorter az the bottom
than nj the top. The hues, being heated first produce
strong Tessre against ends of the boiler BY this
means transverse rupture is made the under side of
the SHE'LL where the cool water lies THESE ruptures are
thew simply produce slight leaks. Tie boiler OF the
Westied shows transverse rupture OF this KIND Wnlan
had evidently existed for some time This aw eAtehas
over feet along the line OF the ryes on the uhue
side the middle section II does not appear 10 nave
eytended dute the point the lower west side OF
the shell where first break of tine explosion occurred
zgzag line Of partial fracture may GG Ns hnye ans that
the weakest s;s part n % be no SS Of the lower
range of ues these being intensely heated from the ir
nace the engineer having been absent minutes S'y ms
ing declared that the pressure OF steam was then ~
pounds leaving clear presumption that as they were
creased it seems perfectly plain that any slght osciia
ton of the vessel from whatever cause which n.ea e
cool water against surface Of higher temperature so as
IN produce change OF position OF par
ticIes of iron from unequal expansion, must
have reduced cohesion of the sheet enough TO make
explosion almost Inevitable In long ilst oi poef eA-
ndsious upon steamers IL Is shown mat Dy 1af the
reater part OF them occurred a the moment OF starting
nroying that oscillation OF the water within tnc sheIl.
was me cause The existence OF the aw Ia the boiler o
the Wesntld was very likely KNOWN Ia the engineer ana
bremen, from the leaking that must sometimes nave
occurred AT that point But tine break at the rVetng
while IL shows that the latter was thin ana weak hs not
yet been found to sho" any trace oi INC eA''o " 'o
haw." .-........x
At BELLEVUE HOSPITAL.
The morbidly curious multitude that had OBJ
structed the in the vicinity OF Bellevue Hospital
,,oe the accident had dwindled down. yesterday, to