New-York tribune., 1893-12-10
THE DESIGN OF THE COLUMBIA.
TRIPLE SCREWS, HIGH SPEED. AND ECONOMY
OF OPERATION.

OF OPERATION.
To the Editor OF The Tribune.
Sir: In The Tribune of November 16 you pub
lished an article dated Washington. November Is,
which IL somewhat misleading. The title was as fol-
lows: Credit for the Columba-rt Belongs to the
Designer Of Her Machinery-Chief Engineer Mel
villes Splendid Wors-Triple Screws an Unknown
Quantity" II the writer Of this article VIII refer
TO Engineering for July 9. 1880 at pages y TO 5'
he will find the Russian yacht I.vadia described
and illustrated 1t Of about 1900 tons dlsplace-
ment with three propellers and three sets OF three
cylinder compound engines estimated indicated
horsepower each 800. total of lOJOO horse
power, and the estimated speed II knots On
the speed trials on the Cyde-where the vessel was
built-the maximum speed was l5S knots and the
maxmum indicated horsepower was 1880. Also
I'm The British Navy" Vol ]. by Sir Thomas
Brassey G.ongmans). London 1852. at page 1885, ne
Will find this vessel described and Illustrated. If he
will further refer to "a Manual OF Naval Archi-
lecture" by w. ri. White O1urray). London lsS at
page $40. he Will find follows: 'Multiple screws
have also been used in special cases. Some OF the
shollowraught vessels built for service the Mis-
srsipp during the American Civil War had four
screws: the Russian circular ironcads were fitted
with six screws and the Imperial yacht Livadia
has three screws" From those references 1t VIII
appear that the triple screws were not an III
known quantity. but that they had been success
fully used before and the credit for the successful
application Of the triple screws IS not due To MY.
Melville. as the writer claims
In Engineering of April 1897. at page i1o' the
engines Of the olympia. OF the same size and pre-
sumably OF tho same design as those Of the Column
bia. Illustrated from which II appears that 'ne
cylinders Jacketed on the sides OF inc inter
mediate and low pressure cylinders only. whlie inc
high pressure cylinders and the bottoms and covers
of All the cylinders are unjacketed. In the best
practice all the cylinders are fully JacKsr1 ,sa
closed frHroon system. which ~ wasteful or fue
Is adopted. ard the forced hot blast system y WIN WIN
closed furnace s ignored. system whicn II properly
applied and worked would s9ye per ,eh % ho e' cna 1g
endurance OF the vessel and reduce the eNpenes ior
coal. The ratio between the hgh and low prcssurs
cylinders on The Columbia OF 10 w. lpr nam eco o.
6s pounds pressure Is not proper one Tso, rho
nom.cally TO expand steam OF such Lrcssur.. ne
rqo on ,h the F1r pr' y 10 & on to @ S ON the Nor
MAMMA. to I; on the Campana. To !, on tme
TO $50. and on the freight steamer inverShalu'
NIT tina; It Is desirable on cruiser to a,t1n d1 n,
high rnte OF speed with light well-consruc,eI M. a.
have been sainedySi It is equally desirable pro
duce this result with economy or fuel ana so m IN
Tribune Of Noven bcr 10 repor, OF the speed trial
OF the Columbia WAS giyen-yZ Ayerasr snes. ~ .oa
coal consumed. about thirty tons an hour. when
Is The rate Of 81 pounds OF coal sn ar heur Pm
The Tribune Monthy for February isss the seal
capacity oi 4. 'Ss SonmsA at 1888 'S tons So at
full speed the coal In the bunkers would only last
two and three-quarter days. Again. suppose the
Columbia was sent 20 Rio Janelro. ana had oc'a,
sion TO chase vessel at fun speed. her Goa! wonid
cost s. 30 per day AT $40 per ton. the cost mere
or s,ppos. In case OF the Columbia hhd 20
chase the Campania al se1, what would be the re-
suit The Campanla's displacement IL about lo'1o
tons indicated horsepower 5000; maximum aver
no. srce,l al s.r - knots. at cighty-folT reVo-
mtions ~ was reported that she made q squirt On
the trial trip or ten minutes AZ ninety -lhiee Ies 2
iutlons and at the rate of about 2 knots; coal.
pcr lay. nbou 80 tons, coalbunker capacity, apout
Sso tons which would las, about eight days; coal
Der hour 20 tons. coal per Indicated horsepower
per hour l5 pounds. The result would ne mat tne
columbia would be out OF coal IN md-Ocean or
otherwise give mp the chase.
II cannot be truthfuy faid that the design tor
the machinery OF cruisers OF ths class ~ superO,
unless all the well-known fuel-saving q vices are
annIled The peOplc after spending S~nvs for
this vessel ought to have had better result pro,
ducel II IL true that moro economy IN iu'I VIII
hc shown at lower speeds yet that s no reason why
II should not also be shown at fuU speed In the
case OF the Campania no special economy ~ pro-
duced M she is driven to the utmost To- break
recoris and the hot blast system Is not used. as IN
,ha White Star ships. Vet. where all fuel-savinS
annI,nnces are used and forcing IL not resorte1 10.
q I'm the White Star freight vessels then the duty
~ q pounds OF coal per horsepower IL alta ned
such n result should be aimed at In our cruising
resqals 30 that they may be more efficient ana
economical. 400, - '".''-''