New-York daily tribune. [volume] (New-York [N.Y.]) 1842-1866, 1854-01-23
TIE ENGINES OF THE SAN FRANCISCO.

TIE ENGINES OF THE SAN FRANCISCO.
We have already expressed our judgment in regard
to tie original and leading cause of the loss of the San
Francisco. The breaking down Of an important por
ton Of her engine have not dwelt upon because it
did not occur until the ship had become unmanagablc
ard therefore subordinate to the main cause of the
accident But as every particular concerning the loss
OF this i'll ated steamer cannot fail to be interesting and
the fact that her machinery gave out was the cause
of her ultimate abandonment when she might otherwise
lave been saved, we proceed to exhibit the facts in
regard 10 the engine itself
Although embodyng several pecularites, the san
Francisco was not in a much greater degree than many
otter steamers which have left our port, an expert
mental ship. She not the first in which Oyerhang
ing guards have extended the whole length having been
preceded in this respect by the John L. Stevens now
successfully running between Panama and San Francis
the Senator and perhaps by several others designed
to navigate the Pacific Her paddle-whees were of
somewhat unusual though rot by any means untried
construction the object being to maintain the faces of
the paddles in a nearly vertical position and avoid the
puugDg and lifting of the water attending the ordinary
construction when subjected any considerable amount
of dip" The San Francisco was the first instance of
Try but similar wheels are running on the West India
Mail steamers from Great Britain and far from be-
ing as has been stated new invention they may be
found fully denested with plates in edition of Tired
gold, published in London in 1888 or 1889. They are
known MOrgan's Featheriug Padde-whees and it is
worthy of remark that whatever liability TO derange
ment might have been inferred from their complex
mechanism the wheels in this instance failed in no par
tcuar and ascertained by the chief engineer Mr.
Marshall only a few hours before the abandonment of
the vessel to be in every respect perfect when
they left the bands of their constructors
The structure Of the engines of the San francisco
was entirely new, but the novelty in the arrange
meut alone and not in the engines themselves properly
called. She mpelled by two Osclating engines
OF suitable capacity ranged in line fore and aft and in
cned toward each other like the sides of the letter A.
both being connected directly to the same crank. Osc
latpg cylinders are free to vibrate like field pieces on
trunnions or bearings which project from their sides
the trunniOns being made hollow TO permit the ngress
aud escape Of the steam The necessity for connecting
rods working beams and other arrangements is thus
completely avoided and the engine is lighter, more
compact and we may add less liable to accident from
this dimnutiCn of the number of the working parts
But the nature of the accident to the machinery cannot
be csmprehended even By engineers without a knOwl-
edge Of its peculiar arrangement as it is usual in
double-engine steamers TO have two airpumps, either
Of which could upon occasion work alone. Ia we'll
cant attempt to explain the circumstances morning
paper las rendered confusion much worse confOunded
by introducing outline engraving of part Of the
engines Of the Golden Gate or Illinois both of which
are arranged quite differently.
The failure Of the machinery was in the ar-pump
Piston-rod tie oirpump having been worked by sep
erate engine. This was a novel and as is now plainly
apparent nirjudieous contrivance. We will endeaSOr
to show how and why the fracture occurred in order
to do which intelligbly will first describe some Of
tie more usual arrangements.
TIE condenser is strong iron vessel in which it
IS iuperatvely necessary 10 maintain toleTable va
cum. The working Of the engines however, contin-
TALLY throws into it large quantities Of water and steam
the latter being moslJ condensed and adding TO the
OF tie former and tie whole requiring TO be con-
stauy pumped against the pressure of the air The
large Iunps employed for this purpose termed air
pumps The San Francisco had only one, but this was
GGe double acting The fracture was not on account
Of its construction, or Of any especial weakness in the
parts tu. proceeded directly from the manner in which
il was worked In al the ordinary form the ar-pump
is worked by attaching it in some manner to the main
engine or engines, in which case it works moderately
but powerfully, aud is so prop0roned as TO maintain
the oa the pstOns Of the large engine while
making its strokes necessarily in the same time. The
ofeatng engine affords, unfortunately DO convenient
points for attaching this important auxiliary The Col
den Gate, running the Pacific, which has two Of the
largest osc,lators in the world connects both It's
| airpumps to a crank forged for the purpose in
its intermediate shaft The Illinois, plying between
/ this port and Aspinwall is arranged in precisely
similar uanuer. the two engines osclatiDg directly
under TIE slafr, each side while tie two air.
pumps stand inclined toward each other on the line
Of The heel The PoEderous intermediate shaft Of the
Illinois forged for this purpose at tie Franklin Forge
in this City, if probably the hea7ies: piece OF wrought
iTon ever executed IN the world and weighed Ia the
roueh left by the hammer $3.50 lbs OF nearly q
The single oecillarng cylinder Of the Augusta
1urrirg between this port and Savannah stands be-
re-h tie sha in tie ceter, ind tie air pump worked
ly lever suspended above and receiving melton from
tie crsnk by link or short connecting rod 4 similar
lever Is adopted in tie new steamship knoxville nov
beng completed ~ tie Novelty Iron Works. bus this
c1TtDgement waS ccll1oret slrost OF quite impossible
IN the San Francisco IL consequence O. the two eaes
connecting to the same craukpin with an addition ~