The sun. [volume] (New York [N.Y.]) 1833-1916, 1900-05-19
TRIALS or THE VIPER.
The Turbine Torpedo Boat Destroyer Files In
a Rough Sea.

from me LordOn Ilrlrs.
on Friday last an event which has been looked
forward TO with considerable interest In the
engineering world for some time past was sue
~cessfully~ accomplished This was the trial OF
her MaIesty's torpedo boat destroyer viper.
fitted with the Parsons steam turbine,
Tho boat itself Is OF the ordinary destroyer
type. excepting that the scantling has been IN
creased In some respects in order to PROVIDE
against the additional stresses due to the large
extra power developed bv the machinery. Thus
the rlddor stock is Of solid steel and Is IA
inches in diameter. which l. probably l inch 10
IA inch more than the dimensions OF the ma
Jority of these craft The boilers are OF the
iarrow type. The Viper is 2i0 feet long. II
feet wide. and ~ feet o inches deep, She VIII
have the usual torpedo and gun armament Tor
vessels Of her class, The boilers are four,
In the engine room one meets with something
quite different 10 the familiar double row oil
twin-screw engines. with their four cylinders,
between which is the passage from end TO END.
In place Of this one descends on to a platform
stretching right athwartships, where are the
large stop valves which control the How OF
steam 90 the turbines and by which alone the
engines are mGnpuvred for there Is naturally
no valve m~otion-or. for that matter, no engine
valves nor any reversing gear, Beneath TINS
platform Is placed a good half OF the engines
that is to say, the part which corresponds TO
the high pressure cylinders Of an ordinary COM
pound engine. These turbines are. IN fact, quite
invisible. being slowed away under the floor.
and need no attention whether running or
standing. A little further aft are TO be seen in
the bottom Of the vessel the larger low-pressure
turbines. but the most conspicuous features are
the. two large cylindrical .condensers. which.
with their pipes and attachments. occupy the
larger part of the room-a fact that will give an
idea OF the saving in useful space gained by
ON Friday it was blowing hard. but.
though the waves were much, bigger than
was desirable for speed it was determined to
make the trial, Tn vessel was taken ont, ana
steamed M the coast To the measured mile and
commenced her trial runs rather before he
fnll power had been worked M. Rejecting the
first runs and taking the following six. II was
found that the speed was Just on 81. knots.
The best pair of runs gave "a 81 knots. 1T
should be stated that the boat had been In the
water some time waiting for her trials and
with n "scribbed' bottom would undoubtedly
have done better. The wind and rough water
We're also against high speed. .
The mean revolutions on the mile were. about
1850, and the steam pressure ranged from
1866 to lb pounds, Unfortunately. the REFER
valves were set rather light and a great guam
THY Of steam escaped when the pressure was
iIl'N'u " lul hBs AH' I lOh' w.
40 tons, but 10 tons were. actually carried
The displacement at trial draught was $40
tons. As the steam turbine cannot be re-
vcrsed there IL a separate one for going
astern, the speed in that direction being
about 1871 knots. The air pressure for
draught averaged about 3-inches on the
water gauge After the runs on the mile the
Viper steamed down the Durham coast and
completed successfully her three hoursl official
trial al full speed, The indicated horse power
Is said 10 have been 1000, but Of course no
indicator diagrams can be taken with an engine
of this nature.
There are four lines of shafting in all. and on
each propeller shaft there are two propellers; so
that there are eight screws in all, or one less
than In the Turbinia. that vessel having, II will
Toe remembered, three shafts and three screws
on each shaft. The need for this multiple screw
steam turbine to be efficient must work at n
high rotating speed. For instance. the tur-
bines of the Wipe on Friday averaged during
the runs on q milo about 1850 turns n minute,
n speed Of revolution that may be compared
10 the 400 turns a minute of the ordinary de-
considered remarkable performances
Unfortunately, when the speed Of a
propeller blade through the water Is
very high, the Water has not time 10 close in at
the back Of II. - that a vacuum Is, formed. and
Of the engine ahd nbsorbs uselessly a ereatdeal
OF power ThH phenomenon is that known to
marine engineers rs ".cavitation," a new form
Of propeller disease, tho diagnosing of which is
due TO Mr. sydney W, Barnaby in his expert
mentso on a Thornycrof' destroyer. II Is %cavita-
MIR Parsons has TO overcome, and IT may be-
said that some Of the most delightful expert
mental work carried out In recent times has
been undertaken by Mr., Parsons In this field.