The Sun.
London, England, 1863-03-02 00:00:00

FHE SUN, LONDON, MONDAY EVENING, MARCH 2, 1863.

Trial of the Double Screw Steamship Kate.

One of those events which gain for themselves by

their acknowledged importance and success a dis-
tinct and prominent position in the history of the
subject to which they belong took place on the
Thames "on Saturday in
.the trial of the double
screw steamship Kate. 1n November last the
Flora, a vessel of 400 tons, was launched by the

same firm that has constructed the Kate—Messrs.

Dudgeon!Brothers, of Limehouse, and was the first
instance of the double screw being successfully ap-

plied to a vessel of any size, each screw being
worked by independent engines. So much impor-
tance was attached to the disposition of the pro-

pelling power of the Flora by the Admiralty, that
Mr. John Dinnen, the inspecting officer to the
Board in the steam department, was appointed spe-

cially to watch and report upon the ship's progress
and outfit, and to attend the trial trip of the vessel
and draw up a report of the results for the infor-

mation of their lordships. The trial proved to be a
great success, for by the working of the two screws
on each side of the dead wood a perfect steering
power was obtained with the ship going either
ahead or astern without any assistance from or use
of the rudder, and by reversing the screws—that
is, working them in opposite directions—the

Flora turned round upon her centre as upon a
pivot, after the manner of a turntable. She was

also very fast under steam, with engines of little
more than one-fourth horse power to tonnage, great
capacity of hold, and light draught of water. It
will at once been seen that here are properties the
want of which constitutes the chief defects of our
war ships under steam. The Warrior and Black

Prince each requires from 8 to 12 minutes to com-
plete a circle when under full steam, and would
therefore be unable to perform such an evolution
in narrow waters, so that they are both to a great

extent useless for inshore work in the mouth of an

enemy's river or at the entrance to a port; while
a vessel of moderate draught
of water; carrying
a heavy armament, with large engine power and
a power of turning upon her centre, would
always be ready for any service in shore or out at
sea, while more stately but unwieldy vessels with
their single screw could but look on and admire, but
could never hope to emulate the performance of
their more agile sister. In addition to these advan-

tages, which the double screw offers to ships of war,
there are others of an almost equally important
character which a ship would possess fitted on the
principle. No apertures are needed:as " screw wells"
in the stern, which would therefore resume its
normal strength. There would be no outer stern-
posts to knock away, and thus depriving the ship
at one blow of the services of both rudder and screw,
and even if one screw should be disabled in action
—a contingency not very likely to ensue from their
peculiar position—one would still remain to propel
the ship, and if the rudder itself was carried away,
the ship's steering power would remain perfect in
her screws. In fact, the whole question has such
an important bearing, look at it in whatever light
we may,
whether as a power of steering ships of

commerce under steam when threading tortuous
rivers, or ships of war when engaged with the
enemy's ships or forts, that the great interest which
has been displayed by the Admiralty and many
naval and scientific men in the trials of the two
vessels, the Flora in November last, and the Kate
on Saturday, is fully accounted for. The Kate is an
iron vessel of 500 tons capacity of hold, and 80 tons
capacity of coal bunkers. She is 165 feet in length
between perpendiculars, 22 feet 6 inches in breadth,
and 13 feet 6 inches depth of hold. Her estimated
displacement is 500 tons. On Saturday she drew
7ft. 2in. aft and Mt. 4in. forward, with an area of
midship section in square feet, at her present draught
of water, of 135 ft. She is perfectly flat in her floor at
the midship section and without keel. On deck she
is fitted with a hurricane-house, 3-4ths of the deck's
length affording ample cabin passenger accommoda-
tion. She carries two masts, lightly rigged, for fore
and aft sails, each mast of wood, and fitting in an iron
socket just above the level of the hurricane house and
with parting joints. The funnel is also telescopic,
so that the masts and funnel could be lowered on
deck, and the Kate, if a war vessel, could lie in un-
der the land almost invisible in waiting for herprcy.
She is fitted wiih two engines with 26in. cylinders
and a 21in. stroke, supplied with steam by two
tubular boilers at 201 b. pressure, a blast pipe lead-
ing from the boilers to the funnel. Each engine
works independently of the other, and drives a
three-bladed screw of 7ft. 6in. diameter, and 14ft.
6in. pitch, the centres of the two shafts being Oft.
6in. apart.
The Kate weighed her anchor off Gravesend at
noon on Saturday, and came alongside Tilbury-pier
to take in the officials and visitors for the trip, lying
alongside the pier with her head up the river. Up-
wards of 60 gentlemen arrived by train from town,
and went down the river in the ship to witness her
capabilities. Mr. John Dinnen, inspecting officer
to the Admiralty, attended by order of the Con-
troller of the Navy, to conduct the day's experi-
ments and report officially upon them. Among the
visitors present were Rear-Admiral Sir R Belcher,
C. 8., Rear-Admiral Horatio T. Austin, C. 8., Capt.
Marin H. Jansen, of the Dutch Royal Navy, and
attached to the Ministry of Marine at Amsterdam.
Captains Jasper Selwyn and Howes, R.N., and
Commander Symonds, R.N., Mr. Kinnear, C.E.,
superintendent of machinery to the Anglo-Chinese
squadron, and a number of other officers and gen-
tlemen whose names are well known in their pro-
fession and in the scientific world.
At a quarter past 12 the Kate started on her trip,
in charge of Mr. Lee, Trinity pilot, and in leaving
the pier strikingly demonstrated her power of turn-
ing by bringing her head round at once down the
river in less than nor own length from the pier,
while at the same time another screw steamer off in
the stream was taking up the entire width of the
river in attempts to get her head down, and had not
accomplished the feat until the Kate was a good
mile on her way. A light easterly breeze prevailed
with a good deal of fog hanging about the river,
which rendered it for some considerable time doubt-
ful whether the intended experiments could be car-
ried out. As the ship neared the Nore Light Vessel
however, the sun came out brighter, and parti-
ally dispersed the fog, so as to admit of the
experiments, so far as related to maritime pur-
poses, being carried out in their entirety. The
speed trial was, however, without any certain value,
for the reason that no given mark could be seen to
steer upon in the run to and from the Mouse and
the Nore Lights, and the ship's course being there-
fore more serpentine than otherwise. The run
back from the Mouse to the Nore, which was the
fairest run of the two, occupied 35 minutes. The
Kate is 100 tons larger than the Flora, but,
although she has only the same engine power as the
latter, there is no doubt but that she is nearly, if
not quite, her equal in speed. The chief interest,
however, lay in the capabilities of the ship in
manoeuvring and rapidly shifting her position under
steam, and the experiments under this head were
carried out in the following order, the vessel being
placed in a position for the purpose clear of the
Mouse Light Vessel:-
1. Both engines going ahead at full speed, three
circles were first made to port, the mean time of
the ship completing each circle being 3 min. 46 sec.,
and the first half of the first circle being completed
in 2 min. 40 sec. The diameter of the circle was
about three times the ship's length.
2. With the starboard engines going ahead and
the port engine stopped, the rudder was put over
hard to starboard, and one circle completed in 3
min. 57 sec., and the second in 4 min., the diame-
ter of the circles being twice the ship's length.
3. With one engine going ahead and the other
astern at full speed, the rudder was put over to star-
board and two circles thus completed—one in 3
rain. 44 sec., and the other in 3 min. 55 sec. In this
experiment the ship revolved upon her own centre
as the Flora did in November last ; and if she had
been a ship of war attacking an enemy's ship or
fort, could have discharged the guns on each broad-
side as they came to bear in turn upon the object.
While the ship was thus revolving a piece of wood
thrown overboard remained alongside the ship until
the conclusion of the experiment.
4. With the rudder fixed amidships, the fore-
going experiment with the screws working opposite
ways, was repeated, the first circle being made in