The daily morning journal and courier. [volume] (New Haven, Conn.) 1894-1907, 1900-11-13

sons. In the case of the Viper all the
underwater fittings such as rudder, the
shafts, and the propeller blades and
bosses, and so forth, have all been de-
signed to stand the highest speed of
over thirty-six knots, and are of con-
Sderably larger and heavier scantlings
than usual, and in consequence offer in
creased resistance to their passage
through the water. So much for the
shlpbuilders' point Of view
Now for the engineers side of the
question. To give to the Viper her five
extra knots, and to absorb usefully the
relatively enormous horse power devel-
oped by her engines, her propellers have
extra width of blade and a much great
er total blade area than that of the AL
batross, whose maximum horse power
is only about two-thirds of the Viper's.
This greater blade area is not only use
less at lower speeds, but involves a
positive waste Of power as such speeds,
! owing to the increased skin friction.
If, on the other hand, the Viper's pro-
pellers had been designed for a maxi
mum speed of only thirty-tWo knots
(the contract speed of the Albatross),
they would undoubtedly have given SUI
perior results at about thirty-one knots.
Then as regards the turbine engines
themselves. At the speed of thirty-one
knots the vipers engines are working
at only two-thirds full power, and are
necessarily less economical than If they
had been smaller and designed for the
power required for thirty-two knots
Then there are the boilers to compare
"a very important item in the case.
The Viper has the well-known Var
row boilers, of simple construction and
of great durability and power, but is
without any refnements external to
the boiler for attaining the highest
possible economy of coal-refnements,
be it said of somewhat doubtful adj
vantage in ordinary service. The AL
batross, on the other hand, has the
well-known Thornycroft boiler she has
also feed water heaters to increase the
efficiency, and also compressed air jets
for promoting more complete combus-
ton of the furnace gases before coming
in contact with the tubes.
These are now the factors of chief
Importance bearing upon the question
of the relative coal consumptlons Of the
turbine engines and reciprocating en-
gines in the respective vessels.
On the one hand we have the larger
engines, greater propeller blade area,
heavier underwater fittings, greater
hull resistance, powerful, durable boil
ers of simple construction without eX-
ternal adjuncts for attaining the high
est economy on trial, the vessel being
capable of a speed of five knots In ex-
cess of any vessel propelled by recipro-
eating engines
On the other hand, we have vessel
whose engines and propellers are capa-
BILE of developing only about two-thirds
of the horse power of the other, de-
signed for much lower speed-in fact,
about that at which the comparison Is
taken--and having boilers Of noted ef-
ficiency in cola, assisted by somewhat
complex additions for further increas-
ing the economy.
That the reduction In the coal CON
attributable TO the aggregate
of these important differences greatly
exceeds the difference between the col
Of the Viper and the AL
batross at about thirty-one knots speed
there can be no question whatever, and
there cannot be the slghtet dousbt that
in every class of vessel excepting only
very small or slow vessels) 1t will be
found that the turbine system of pro-
pulsion will give superior results over
the reciprocatlng engine as regards coal
In the Viper, In spite of these losses of
power at lower speeds which we have
described, and incurred in order to
reach the record speeds attained
(speeds only attainable by turbine ma
without any special effort to
attain economy, even so, her coal con-
per horse power realized is
very little in excess of the best and less
han that of many of the thirty-knot
1estroyers.
In the specifications of most admiral /
les for torpedo boats and destroyers t
he question of speed is placed in the /
orepart and enforced under heavy PEN c
ilties, eliminating with the option of |
complete rejection of the vessel should 6
he deficit reach more than two to t
-hree knots below that contracted for. {
rhe coal consumption is relatively I
placed In the background. 9
This being so, the designers of the t
Viper may be pardoned If they have r
made every effort to attain the highest I
possible speed and have not given suf- a
icient consideration to the question of c
obtaining the utmost economy OF fuel !.
t which turbines are capable, but in
his their first destroyer they can at o
east claim to have beaten all records
f speed by long interval, and in their n
uture ships they will be able to show p
y how much they can beat all records S
$ to economy in coal. t
Yours faithfully, n
CHARLES A. PARSONS, p
damaging Director Turbinia Works u
London Times. e.