New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1899-10-08

than almost anywhere else in the war Vessel,
the constant demand has been FOR greater power
on less weight and at the same time the demand
has also been for thoroughly reliable machinery
that would also be economical
FURNISHING POWER FOR wARsHIPs.
Progress has been SO rapid that it sometimes
seems that We hardly have time 70 get out a
design nearly perfect Us possible and see IL
thoroughly tested in service before improvements
have been sugs ssted that render what appeared
SO perfect relatively obsolete.
Shortly befor. | became Engineering Chief Of
the Navy, forced draught had been reintro-
ducei after many years Of disuse, which at once
gave enormous increase Of boiler power with
n very slight increase Of weight, due 70 the
burning Of much larger amount Of coal on
given CRATE surface The shell boiler was de-
yeoped until its design seemed nearly perfect,
but we were confronted with the problem OF
getting plates sufficiently thick 20 withstand the
Increasing steam prcssures III the large boilers
and still be aOl. to properly work the plates In
our shops The light Of these boilers was al
ways very great for the power developed and
I'm the large sizes which they had reached the
utmost skill was necessary for their proper care
and maintenance. Shortly before tn time had
come when further progress with the shell boiler
seemed impossible the water tube boiler WAS
developed . such point that it gave US the
necessary solution ~ the problem, and It now
seems quite certain that. for some time 20 come
AT least the boiler problem has resolved itself
into determination Of the best form Of water
tube boiler inaeInuCh As we are now sure that
We can construct boilers which will Withstand
any prossures that are likely 20 be used and
which are satisfactory in every other respect.
These boilers offer almost absolute safety
against disastrous explosion, afford . great re-
ducti0n in weight. and built 70 Withstand
comparatively rough treatment far heat
is concerned. thus giving freedom from such
troubles as leaky tubes and leaky seams 70
which large shell boilers very liable.
The demand FOR reduction OF weights In the
engines has been mot by the use of stronger ma
telials. and also their disposition IN shapes
where given weight Of material offers the
greatest resistance. We thus have steel cast
ings 10 repl zee east iron; hollow rOrgings u oil
tempered steel and the use Of bronzes Of double
the strength of the older COMPOSITIONS. Besides
the greater strength Of the materials. just as
important an item Is their much greater RELIABLE
ity. our manufacturers today can furnish us
with forg!ngs where We know that the results
obtained on test pieces viii De- absolutely true or
every part Of the whole mass.
Weights have also been greatly reduced by
using engines which run az much greater speeds
than formerly obtained This seems a sufficient
ly simple matter and yet = was not possible IN
I'll the Improvement came IN materials, combined
with an accurate scientific knowledge or some
of the questions confronting the marine enGi-
neer which had formerly been solved almost by
rule OF thumb This IS notably the case with
propeller design, FOR II WAS the mistaken notions
on this point that really held down the engine
eIe,ri- Ir4smuch MS the whole Office ~ the mo-
tive machinery IS 20 turn tha propellers. It might
seem that e. would ho necessary % design the
propeller first and make every thing else 70 suit
n Int fortunately now that 49,. have accurate
scientific frowiodre of the conditions governing
propeller DESIGN we know that tho propeller can
he arranged o. suit almost any speeds found
desirable for The engines. and this enables Us -
choose. ,refno speeds which VIII civ" Us both
lighter and more economical ones than were pos
slhle in oldeu days.
4 problem in the design % engines FOR war
vessels which g. ~ considerable difficulty, ana
tho solution ~ which Is not yet thoroughly satls
factory Is that ~ securing economical results az
ordinary cruising speeds with the capacity l.'
tho power necessary at maximum speeds a.
WON ar. Doubtless aware the power necessary 70
lrfv. "A vessel varies approximately as the 'un'
~ tho speed that IT, as IL ordinarily 'l' 49,
fl. cruising speed is about nan me 4itN'"-''.,
fh.. r.v..r 10 Doe developed Is one-eisA'h 81 -
= fh. maximum A. was very crNeIE
,.r.e.,.l h, one. ~ my former assistants u io.,'
e,r Hollis, some years ago. the plonie" = '
mar ~ having a beast o, burden WHvSe ma ma.
nm n, mower Kill be that Of an elrphaH.,, -.
whose appetlte Is 50 adjustahlr ma u, 49,
llv used for work which couiu pe pr
t d. n donkey You well know tnat an
- INT would eat about the same WHa'r'.'
.., h. was doing and while this If not "Na''y
80. ~ a steam engine II neNritheirS5 ~ lur
49,. 49,. ~.ln.rnv when worked ~ powers Whlch
1.i"' nb o. ANAL percentage ~ the maximum is
49,. ,n,,ch r,ducrd In some ~ our shlps we
ba,. tried ~ solve this by arranging Two sets or
',,rin.. ON each shaft that at the moderate
,o,.ars the forward get can he uncoupled. Inc
i'm fatel Maine had an arrangement whereby the
large cylinders 81 her trl" expansion engines
could he disconnected leaving the engines 10
run as smaller compounds at cruising speeds. \
somewhat similar arrangement IL In use on the
Nashville where the large cylinder u quad
rupla expansion engine can be thrown out l"aV-
ing a triDi, expansion for lower powers me
affection 10 all Of these Is that II II becomes
nee, esarv in an emergency 70 get full power Il
il often impossible to stop to couple up rms