National Republican., 1886-03-20
AMERICAN MACHINERY.
THE SUPERIORITY OF HOME-BUILT EN-
GINEs OVER ENGLISH.
A Talk With nm Expert About War
Ship Locomotion and the Best Means
of Accomplishing It-AII About Fuel,
Horse Power, and Speed.

A reporter for the NATIONAL REPUDL1.
CAN called upon Chief Engineer N. b.
Clark, United States navy, to ascertain his
Views in reference to the relative merits OF
American and foreign steam machinery,
now being discussed by Congress and the
press.
Mr.. Clark said the great mistake made
with war ships is that the same type Of
steam machinery is put in them that is APP
proprlate for merchant steamers, making
regular trips, which have TO be designed to
run at high speed, with economy Of fuel
week after week.
"How much coal per horse power does a
well.designed marine engine consumer
"a compound engine when running at
moderately high speed consumes about two
pounds OF coal per indicated horse power
per hour, but when running at low speed
much more coal Is required to produce q
horse power.n
"How is that; always thought economy
OF fuel was attained by running ut low
speed ~
$50 It is, so far as the application of the
power generated is concerned, but when q
large engine is used to generate small
power It does not work with economy. For
the same quantity OF coal vessel would run
four times as far at nine knots per hour as she
would at eighteen knots. But when run
ming at low speed, say at nine knots,
only eighth the power is needed, and
the amount Of coal per horse power is con-
siderably increased by the radiation and
friction incident to large engine develop
ing q small power, thereby considerably in-
creasing the cost Of power per unit Of coal
consumed. Hence the apparent paradox,
when the engines OF naval vessel are run
slow for economy they consume fuel with
wasteful extravaganza
''You have mentioned eighteen knots as
an appropriate emergency speed and nine
knots as q passage speed. What proper
ton Of the coal supply would be consumed
at each rate Of speedy ~
"There would be no occasion to exert the
high emergency power In time Of peace ex-
cept for exercise at drill, to familiarlZe the
officers and men with their duties, and In
addition thereto, in time Of war it would
only be used when chasing an enemy or
escaping from superior force. Therefore
the proportion Of coal consumed for emer-
gency power would probably not exceed .
per cent, leaving 90 per cent. OF the entire
fuel supply to be consumed at low speed.
At the present time the steam machinery OF
war ships Of all nations is designed to effect
economy In the consumption OF the fuel
used at high speed and for wasteful extrava-
gance in the consumption Of that used at
low speed, and is handicapped with an
enormous weight in order to accomplish
that result.n
"You speak of using the high emergency
power in time Of peace only for exercise at
drill. suppose you would regard the ex-
penditure of fuel for that power somewhat
us you would that Of ammunition for the
guns, both being consumed to familiarlze
the officers and men with their dutiesT'
"Precisely SO; the emergency power
would be required only to take the ship In
and out of action, and the guns would be
used only while in action, and while there
would be sufficient fuel to run the emer-
gency power for five days, the guns would
use their entire complement of ammunition
in less than three hours rapid and continu-
GUS firingn
"What is the weight of the steam ma
chlnery Of war ship per horse powerp"
sin the British navy the average weight
Of the steam machinery is 800 per horse
power, with $50 for the swift dispatch vessels
Iris and Mercury, and $50 for the torpedo
ram Polyphemus, and that Of the first clast
torpedo boats Of English design is 81 pound
while the fastest torpedo boat engine o.
| American design and build only 80 pounds
The weight Of all steam engines Of Ameri
can design Is invariably less per indicated
h0Tss h0I1S power than the same class of English
|
"The difference between thrty-nint
pounds per indicated horse power IN
the fast American torpedo boat engines
| aud AS pounds In the Boston
| and Atlanta seems to be high price TO
| pay for the economy of fuel obtained by itE
use, on rare occasions, for short periods Of
time Tor upon about per cent. of the fuel)
particularly when we consider that thi:
| ponderous machinery itself has to be carried
| at the high speed, and that additional powel
must be applied to overcome the resistance
| due to Its weight.n
"What remedy do you propose to apply
| In this condition OF affairsS"
"Design light running, swift moving en-
| gines, analogous to those Of the American
| torpedo boats and launches, sufficient,
augmented in weight to give the endurance
| required for the emergency power OF wa
ship; and by applying two or more separate
engines to each shaft Of the twin screws, 81
that one engine on each screw can be dis
| connected, when running at low speed
thereby avoiding the loss incident to larg
engine developing a small power"
"What weight Of steam machinery woul
| you propose"
''lf the torpedo boat machinery was aug
mented In weight about 100 per cent l
would give ample endurance for the emer
gency power Of war ship, and would b
eminently appropriate thereto on accoun
OF the great economy when running at loy
speed.
''Many Industrial establishments In thi
| country are now using number OF small
engines Of high piston speed, distributed
through the works and applied directly I,
the machine to be run, In place OF the large
centrally located engine formerly used"
"Are you In favor Of horizontal enginesT
i ',The only excuse for the application o
horizontal engines to war ships was tina
they could be protected below the waite
line, but, since the development of grea
power by the torpedo type Of engines, hav
ing vertical cylinders OF such small heigh
that they will go below the water line o
the llghtest draught vessel, there is no eX
cuse whatever for the further application o
the clumsy, ponderous horizontal engine
so difficult to keep In repair"
| "Can you give an example OF vesse
with specified weights to illustrate you
proposition 9n
"The British torpedo boat Childers ha
steam machinery weighing 57.7 pounds pc
horse power. The compound engines hay
with 15 inches stroke of piston, are 81 fee
high, and develop 700 horse power. II thes
engines were amplified to develop 1877
horse power, the cylinders would be l0l an
"a inches diameter with 81 inches strok
of piston, and would measure 11.0 feet high
The British dispatch vessel Mercury has
displacement OF 8, ,735 tons, has 1900 hors
power, and has attained a speed Of 1873
knots on the measured mile. The weigh
of the Mercury's steam machinery is 90
tons. The weight of four engines of til
type and proportions Of the Childers, {
1875 horse power each, aggregatlng 7,5O
horse power, augmented in weight 100 pc
cent, would be 1868 tons, thereby savin
5S1.7 tons In the weight of steam machiner.
which, II ludiciously disposed In water-lir
duce a vessel of high speed, almost con
pletely invulnerable TO shot and shel
thereby augmenting the fighting force full
tenfold.
"The lack Of endurance of the torpedo
boat type OF machinery pertains more
the boilers than to the engines, but |