The Sun.
London, England, 1860-01-30 00:00:00

2HE NAVY.

Rear Admiral of the White, Hon. Sir Henry
Keppel, K.C.8., has been appointed to the com-
mand of the Cape of Good Hope and the West
Coast of Africa station, vice Rear Admiral the
Hon. Sir F. W. Grey, G.C.8., and he will shortly
hoist his flag on board the new 51 gun screw fri-
gate Forte at Sheerness.
The Perseverance, screw, Commander E. R.
Power, sailed from Portsmouth on Saturday, with
the head-quarters of the Ist battalion 9th Foot on
board, for Corfu.

The Sprightly paddle, Master Commander Allen,
arrived at Portsmouth on Saturday, from Devonport.
The Diadem, 32, screw, Capt. James H. Cock-
burn, and the Alacrity, 4, screw gun vessel, Com-
mander J. R. E. Baird, both arrived at Spithead on
Saturday morning, the former from the westward,
and the latter from the eastward.

The Pigmy, Master Commander Johnstone,
sailed from Portsmouth for the westward on Satur-
day.

The Mersey, 40, screw, Capt. H. Caldwell, C. 8.,
got under way at ISpithead on Saturday morning,
and proceeded to the trial ground in Stokes-bay, in
charge of Capt. George T. Gordon, commanding
steam reserve at Portsmouth, to test her " Griffiths"
propeller. Mr. J. Dinnen, the Admiralty inspec-
tor of machinery afloat, Mr. G. Murdoch, inspector
afloat at Portsmouth, and Mr. Miller, assistant chief
engineer at Portsmouth, were also on board to super-
intend the trial. The Admiralty having entered into
an agreement with the patentee of the " Griffiths"
propeller to pay a " royalty" of a certain sum per
horse power for all vessels in her Majesty's
navy to which his principle might be applied,
the present trial was instituted to test ,
the comparative merits of the Griffiths'
and the common screw, as used on the ship's
trial trip in Stokes-bay, on the 23d of March.
1859, and reported in The Sun of the following day.
Saturday proved as favourable in every point of
view for the trial as could possibly have been *de-
sired, but at one time an accident occurred which
might have led to very serious results. The ship,
at the conclusion of one of her runs, was on the
point of rounding to for commencing another run
to the westward, when the wheel ropes carried
away, and for some moments the Mersey, with her
head to the shore, going at full speed, was in dan-
ger of running full tilt on the ground. Prompt
measures on deck and in the engine-room, however,
averted the catastrophe. Six runs were made at
the measured mile, and the results gave the ship a
speed, in knots, of 12 and eight-tenths. Draught
of water—forward, 21 feet 4 inches ; aft, 22 feet 10
inchesr Pressure of steam—in the boilers, 201 b. ;
on engines, 191 b. Average revolutions of engines,
571 ; the maximum being 59: Diameter of screw,
20 feet ; pitch, 29. The following is a description

of the screw—" Griffiths," with the blades attached

to the boss or sphere, on Messrs. Maudslay's plan.
The ship's steering properties were found to be
good, and with the helm hard a-starboard, under
full steam, she made a complete circle in eight
minutes six seconds. The speed realised on the
trial trip in March last was 13.290, with the maxi-
mum of 56 revolutions of engines. The present
trial, therefore, shows an increase of indicated horse
power of engines, but a decrease of half a knot per
hour in the ship's speed. The loss in speed may
be accounted for in two ways. The ship is now
five and a half inches deeper in the water than on
the former trial, and as she has notbeen in dock since
she has been in commission, her bottom must neces-
sarily be foul, and the only means to arive at a correct

conciusiod as to the merits of the two screws in

point of speed would be for the Mersey to re-ship
her old screw, and test it under circumstances of
wind and weather as closely approximating to
Saturday's trial as possible. The vibration of the
Mersey on Saturday was not so great as in March
last, and up to nearly three-qvarter speed there

was not much perceptible ; from three-quarter to
full speed it very sensibly increased, but as it is a
characteristic feature of the Mersey to drive a tre-
mendous sea before her when at full speed, it may
be a question as to what amount of the vibration
really arises from that cause alone. A different
pitch of the screw might also increase the ship's
speed, but it is very doubtful whether the Mersey
will ever excel, if she even equals, whatever form
of screw be applied to her, the rate of speed she
realised on her trial trip of March, 1859.
The Ariadne, 26, screw, Capt. Vansittart, is ex-

pected to get under way from Spithead about noon
to-day, and test her altered screw in Stokes Bay.

The following appointments were made on Satur-
day at the Admiralty :—Charles Barney, master
additional, to the Dasher ; John D. Rogers, master,
to the Dasher; Samuel Libby (B), master, to the
Fawn ; W. A. Dinnen, chief engineer, to the Asia,
for service in the Prince of Wales ; John G. Oak-

shott, chief engineer, to the Conqueror ; J. Churcher,

chief engineer, to the Cumberland, for service in
the Tartar; Dr. J. Gallagben, surgeon, to the Sans-
pareil; W. R. Dalton, surgeon, to the Castor;
John Shepherd, paymaster, to the Racer.