The Sun.
London, England, 1868-02-15 00:00:00

'EBRIJARY 15, 1868.

NAVAL AND MILITARY INTELLIGENCE.

Yesterday her Majesty's unarmoured screw
steamer Blanche, 6 guns, 1,268 tons, with engines
of 330 horse-power, built and fitted out at Chatham
dockyard for a three years' commission, made her
official trial of speed at her deep-load draught at
the measured mile, Maplin Sands ; the customary
speed trial at light draught having been dispensed
with. The Blanche is one of the squadron of im-
proved sloop-corvettes, built after the designs of Mr.
E. J. Reed, the Chief Constructor of the Navy, and,
with regard to dimensions, form of construction, and
engine power, is in all respects similar to the Danae,
Eclipse, and other vessels of her class now building.
On getting under way the Blanche drew 16ft. 7in.
aft, and 13ft. 7in. forward, which was slightly in
excess of that of her sister ship, the Danae, when
tried at the measured mile, awl also rather more
than her deep draiight as designed, the increased
di placement being (lute to the two additional gnus
composing her armament, with the necessary shot,
shell, and ammunition, together with some 30 hands
more than her originally fixed complement. Tile
Blanche left her moorings at 12 o'clock, the officialsl
on board, including Capt. the Hon. A. A.Cochrane.,
C. 8., commanding the Steam lit,!serve, who super-
intended the trials ; Capt. W. lloustou Stewart,
C. 8., Superintendent of Chatham dockyard ; Mr.
'F. H. Baker, chief inspector of machinery ; and Mr.
W. Williams, chief inspector of machinery afloat ;
Mr. R. Dawson, assistant master shipwright, re-
presenting that department. The ship's machinery
was in charge of Mr. Snell, chief engineer; Mr.
Ravenhill, of the firm of Ravenhill and Hodgson,
representing the makers of the engines. The weather
was favourable for the trial, the wind being from
the W.N.W., with a force of from two or three.
After the preliminary run to prepare the furnaces
and boilers, the vessel was placed on the measured
mile, and six runs made at full-boiler poWer with
the following results :—First mile—time, 5 min.
29 sec., speed in knots per hour 10.942, steam 311 b.,
vacuum 27in., revolutions of screw per minute 88 ;
second mile—time, 4min. Isec., speed 14.938 knots,
steam 30M., vacuum 27in., revolutions 88 ; third
mile—time, smin. 20sec., speed 11-250 knots, steam
301 b., vacuum 26in., revolutions 86 ; fourth mile—
time, 4min. 2sec., speed 14.876 knots, steam 301 b.,
vacuum 26in., revolutions 87 ; fifth mile—time,
smin. 23sec., speed 11.146 knots, steam 28ib.,
vacuum 26in., revolutions 84 ; sixth mile—time,
3min. 57sec., speed 15.190, steam 331 b., vacuum
25, revolutions 88. The first means obtained from
these results were 12.940, 13.094, 13.063, 13'011,
and 13.168 knots, and the second means 13.017,
13.028, 13.037, and 13.089 knots, giving the true
mean, or actual speed of the ship, as 13.055 knots
per hour, or nearly two-tenths of a knot per hour
more than the speed of the Danae, which, when
tried at a lesser draught on the 12th ult., at Stokes
Bay, realised a mean speed of 12.872 knots, as
against 13.384 knots per hour at light draught,
showing that the Blanche is, in comparison, a faster
vessel at her deep load draught than the Danae at
her light draught, although both vessels and ma-
chinery were constructed from the same drawings
and patterns. The Danae, it may also be remarked,
is fitted with a Griffith's propeller, and had the same
description of screw been applied to the Blanche
there is little doubt that the results would have been
still more favourable to the latter vessel. At the
close of the full-boiler trials two runs were made at
half-boiler power, with the following results :
First run—time, smin. 36sec., speed 10.714 knots,
steam 301 b., vacuum 27in., number of revolutions
76; second run—time, 4min. 53sec., speed 12.287
knots, steam 301 b., vacuum 27in., revolutions 76 ;
giving the mean speed at half-boiler power exactly
11.5 knots per hour. Throughout the trial the
engines worked very satisfactorily, the actual work
performed, as shown by the indicator cards, being
equivalent 'to 1,900 horse-power. The vessel was
afterwards tried in making circles, stopping and
starting of engines, and other trials, the results, as
in the case of the speed trials, being equally satis-
factory. At the close of the trials the Blanche re-
turned to harbour, and, according to existing orders,
will take her departure for Australia to-day, calling
in at Spithead for final orders. The official inspec-
tion of the vessel was made on Wednesday by Capt.
W. K. Hall, C.B.