The Sun.
London, England, 1865-09-25 00:00:00

Naval and Military Intelligence.

The recent trials of the iron-clad frigate Bellero-
phon, which have been briefly reported in our Naval
Intelligence from day to day, have resulted in one
of the most extraordinary phenomena ever developed
since the introduction of steam propulsion. For three
days in succession this ponderous ship has been
steaming about at the entrance to the Thames and
Medway under circumstances for which all the
science of the day vainly attempts to account, and
which baffles those who have designed, built, and
put engines into the ship, no less than the nau-
tical gentlemen who had charge of her during her
trials. In technical language the phenomena in ques-
tion is denominated " negative slip," but in common
parlance it is spoken of as a case of the ship overrun-
ning the screw, which in this instance has occurred
to an altogether unexampled degree. We may state
the case in the simplest manner to the general reader
by saying shortly that, although throughout the
trials of this ship, while the screw propeller which
drives her has been itself advancing with a speed
barely, if at all, exceeding 12 knots per hour, the
ship herself has been speeding through the water at
a rate of 131 knots. If a phenomenon of this nature
had occurred with a light vessel constructed with
exclusive regard to fleetness it would obviously
have been a singular circumstance, but for it to
happen with an iron ship of war of the stoutest con-
struction, covered with the most ponderous armour
ever yet applied to a seagoing ship, and carrying a
greater weight on a hull only 300 ft. long than the

Warrior carries on a hull nearly 400 f t. long, is a most
unexpected and unaccountable circumstance. This

overrun of the screw by the ship has happened be-

fore in a less degree even in some of our iron clad
ships, but up to the present time people have stead-
fastly refused to believe in it, and have resorted to
many ingenious devices by way of accounting for
it. The first and most obvious explanation was to
attrilute it to errors of calculation or measurement;
another was to attribute it to obscure tidal influ-
ences, and this was favoured by the circumstance
that this has been most frequently observed on the
measured mile at Stokes Bay, where two high and
two low waters are said to happen each tide, the one
resulting from that portion of the Atlantic tidal wave
which finds its way through the Needles Channel at
the west end of the Isle of Wight, and the other from
the portion which flows in round the eastern end of
the island. A further explanation was sought for in
the fact that the screw propeller of a ship works in
a wave of water which is following her, and which
thus adds to the real speed of the screw through the
water—an explanation which is untenable because it
would require that screw ships with full after bodies
would give the best results in steaming, whereas it is
well known that they invariably give the worst. But
perhaps the most popular explanation of all is that
of assuming that the blades of the screw propeller
bend under the resistance of the fluid, and thus be-
come for the time being different screws, having a
greater velocity in advance than when at rest. This
explanation appeared to receive an extraordinary
confirmation in the Achilles, the first iron-clad fri-
gate which was found to overrun the screw, for on
clocking the ship after her first trials it was found
that the blades had actually bent forward and grazed
the sternpost of the ship. The explanation proved
insufficient, however, for on trying the ship again
with stronger blades, the bending of which was out

of the question, nearly the same overrunning of the •
ship was found to happen. In the case of the Mino-
taur also, the trials of which at Stokes Bay were re-
cently reported in great detail in The Sun, the speed
of the ship somewhat exceeded that of the screw.
The Achilles and the Minotaur are, however, ex-
tremely
long ships, with water-lines as sharp as those
of a river steamer, and the excess of the ship's speed
over that of the screw fell in every instance short of
a knot per hour. It is the occurrence of the same
phenomenon in a far greater degree in a short ship
like the Bellerophon, and its repetition day after
day under circumstances which set all the
popular explanations at naught, that give the recent
trials so much importance, and impose upon our
shipbuilders and engineers the duty of thoroughly
investigating and accounting for its existence. If,
in addition to being a short ship the Bellerophon
bad not possessed what in nautical parlance is
known as a very " clean run" aft, the old explana-
tion of the following wave might again have been
adduced i❑ this instance ; but the form of the ship's
after body is as tapering as that of the Minotaur,

and is wholly incompatible with this mode of ac
counting for what has happened. If this subject
possessed only an abstract scientific interest we
should not have taken this notice of it, but it exer-
cises so practical and immediate an influence upon
the speed of ships that it is.calculated to excite the
most general interest among engineers and ship-
builders, and throughout the navy ; for it is found
that with screw propellers that thus lag behind the
ships which they are driving a most injurious drag
is put upon the engines. The engines put into the
Bellerophon are designed expressly to revolve
rapidly, and the ship was taken down the river on
trial with the understanding that the screw would
have been turned round about 70'times per minute,
thus developing 6,000 indicated horse power.
Instead of this, to the astonishment and disappoint-
ment of everybody on board, and of no more than
the engine-makers themselves, who are men of the
greatesteminence, the drag of the four-bladed screw
was found to be so great that not even 60 revolu-
tions could be secured, even when all idea of using
the steam expansively was abandoned and it was al-
lowed to rush with full force into and through the
cylinders. A great waste of steam was thus of
course occasioned, and consequently scarcely 5,000
horse power, instead of 6,000 was developed.
The wonder is that under such circumstances
the high speed of 131 knots was attained, and the
fact that it was the best possible guarantee that
a speed of more than 14 knots will be secured in
this remarkable ship when the full power of her
engines has been developed with a different screw.
The peculiarity of the screw at present applied to
the ship is not limited to the number of its blades.
Each of these four blades is formed with two faces
standing at an angle of inclination to each other, in
order that each half of it may impart a different
velocity to the water, somewhat upon the principle
of the differential screw propeller invented many
years ago by Professor Bennett Woodcroft, of the
Great Seal Patent-office. The Bellerophon's screw
really has eight blades, in fact, arranged in four pairs,
and as the diameter of the whole is no less than
23ft. 6in., the drag which it puts upon the engines
must be truly enormous. So far as we can learn,
neither the designer of the Bellerophon nor the
Admiralty approve such a propeller being applied
to the ship, and after the trials of last week it is hard
to believe that the engineers will care to insist upon
its use. It is understood, however, that one other
trial is to be made of it, with its blades set to a dif-
ferent pitch, as soon as Possible,
and if the result
a two-bladed
then secured be not satisfactory,
Griffiths screw, like that of the Warrior,
will be
fitted to the ship. It is understood that this is what
Mr. Reed would prefer, not only on account of the
steaming qualities of the ship, but because of the
serious obstruction to the speed of the ship under
canvas which the four-bladed screw must necessarily
present. The Bellerophon will be a full-rigged
•
sailing ship as well as a high-speed steamer , but
it is not to be expected that any amount of sail-
power would suffice to propel her rapidly through
the water if subjected to the drag of a screw which
lags so much behind the ship, even when it is itself
the propelling agent. The extreme handiness of
the Bellerophon under the action of her novel form
o f rudder affords the strongest possible induce-
ment to disembarrass her as much as possible from
the hindrance of an improper form of screw. Her
rudder is on what is known as the " balanced
principle," being pivoted near the middle instead of
its forward end, as usual. It is coming into use
rapidly in America, and was tried in the Great Bri-
tain steamship in this country many years ago.
For some cause or other, however, it was prema-
turely abandoned, like many other useful things.
With the exception of an experimental trial in a
small gunboat at Devonport, under the direction of
Capt. Astley Cooper Key, R.N., C. 8., it has never
before been applied to a British ship of war, and it
certainly was a very bold experiment to apply it at
once in so large and powerful a ship as the Bellero-

phon. That ship, however, being of iron, and very
strongly built, afforded a really favourable oppor-
tunity for its trial on a large scale, and the success
attained is most remarkable. It is true the Bel-
lerophon has been designed expressly with a view to
handiness, being made short, and of a light draught
of water forward expressly for this purpose, and she
would no doubt have steered remarkably well with
an ordinary rudder. But it is to the adoption of

the balanced principle that the extreme ease with
which the helm is handled is due. On Friday last
Capt. Randolph, R.N., who had charge of the ship,
and Mr. Reed, themselves took the steeringwheel

with the ship at full speed, and steered her easily

without assistance. At Portsmouth, on the
Minotaur's trial, it required 60 men to put the

rudder over 37 deg. in 20 secs. The Minotaur,
with GO men, turned a circle in 7 min. 15 secs. ; the

Bellerophon, with eight men, turned it in 4i min.

The Minotaur turned the half circle in 3 min. 47

secs. ; the Bellerophon in 1 min. 50 secs. Even

these figures will scarcely enable the reader to fully
realise the handiness of the new frigate; but few
will be at a loss to understand it when it is stated
that while the Admiralty have at length been coin-

pelled to build new and powerful steamtugs in order
to enable the Warrior and other long iron-clad ships
to be got into and out of Portsmouth and Devon-

port harbours, the Bellerophon, after the com-

p letion of her trials on Friday, steamed, without the
aid of tugs merely into sheerness harbour, but har-
sued her way at a speed of 10 8-10 knots (by log)
along the 14 miles of the river Medway's winding
course, threading her way among the long succession
of hulks which encumber that narrow and tortuous
stream, never stopping her engines for a moment
until she reached the sheer-hulk off Chatham Dock-
yard, to which she was secured for the night. This
achievement was one of national interest, and much
credit is due to Capt. Stokes, the master attendant
of the dockyard at Chatham, who had charge of the
ship after Sheerness was passed, for affording so
striking an illustration of the steering capabilities of
our latest iron-clad frigate.
The Euryalus, 35, wooden screw frigate, 2,371
tons, 400 horse-power, Capt. W. M'Dowell, C. 8.,
was paid off on Saturday, after a commission of
three years and eight months as the flagship of Sir
A. L. Kuper, K.C.8., in China and Japan. The
Euryalus was commissioned at Portsmouth on Jan.
23, 1862, by Capt. Josling, for the flag of Rear-
Admiral Kuper, and sailed from England in the
following march. After calling at Madeira, the Cape
of Good Hope, and Singapore, she arrived at Hong-
kong on Aug. 12, and on the 29th sailed thence for
Yokohama, Japan. After visiting Yeddo and Naga-
said she proceeded to Shanghai, where Admiral
Kuper relieved Rear-Admiral Hope in the Imperie use,
in command of the station. The seamen and marines
of the ship were shortly afterwards landed from the
Euryalus and marched toKanding to oppose the rebels,
who were then advancing towards the town. While
engaged on this duty two officers and a large num-
ber of the men died from cholera, and many others
were invalided. The Euryalus afterwards proceeded
to Hongkong, wher she remained until February,
1863, when she sailed for Yokohama. Afterwards,
in August of the same year she sailed with the fleet
for Kagosima, the stronghold of Prince Satsuma,
and engaged the batteries there on the 15th and 16th
of August. On that occasion Captain Josling, the
commander of the ship, and eight seamen were
killed. On the 17th of August the Euryalus re-
turned to Yokohama, and remained there until Sep-
tember, 1864, when she sailed with the combined
allied fleets, representing the English, French, Dutch,
and American flags, for Simonosaki, where an attack
was made on the batteries, a force landed, and the
acts of bravery performed by a midshipman and two
seamen of the Euryalus which led to their being
invested with the Victoria cross at Portsmouth on
Friday last. In this second day's action Captain
Alexander was wounded severely, and several of the
men were also killed and wounded. The officers
and crews of the other ships were not wanting in
bravery on the occasion, as an instance of which we
may mention that the commander and gunner of
one of her Majesty's ships, with the commander of
his Dutch Majesty's ship Medusa, landed from a
boat during the night, after the first day's action,
and spiked the guns of a powerful battery on the
right of the Japanese works, at a time when it was
known that the woods which reached down to and
surrounded the battery on all sides but its sea face
ere swarming with Japanese. In the action of

the following day the battery was powerless. From
Simonosali the Euryalus returned to Yokohama,
Nagasaki, and from the latter to Chusan, whence
the admiral proceeded to Shanghai and Ningpo in
the Coromandel screw gunboat, tender to the flag-
ship. The Euryalus, on the return of Admiral Kuper
in the Coromandel, proceeded to Amoy, Hongkong,
and Singapore, giving up the command of the
station on the 22d May last, at the last named port,
to Vice-Admiral King, who had just arrived from
England in the Princess Royal. On May 27th the
Euryalus sailed from Singapore for England, called
at Batavia, the Cape of Good Hope, St. Helena,
and Ascension, on her way home, and arrived in
Plymouth Sound on the 4th inst., where she after-
wards disembarked Rear-Admiral Sir A. Kuper and
his suite, and then sailed for Portsmouth. Of the
crew of the Euryalus, John Richards, Admiral's
coxswain, and William Hewett, sailmaker, are re-
commended to the Admiralty for medals and gratui-
ties for long service and good conduct.
The screw steam frigate Liverpool, 39, Capt. R.
Lambert, now at Devonport, will; it is expected, be
sent back to Ireland.

The screw steam frigate Arethusa, 35, Capt. Mac-
donald, which vacated the Prince's Dock, at Devon-
port, on Thursday afternoon, made a trial of her
machinery outside Plymouth Sound on Saturday.
On her passage to Madeira she will be accompanied
from Plymouth by the Constance, now in the Sound,
and by the Octavia, which arrived there from Spit-
head on Thursday.
The iron screw steam store ship Supply, 2, Staff
Commander Chas. Bowden, from Woolwich, which
arrived at Plymouth on Friday morning, left in the
afternoon for Gibraltar and Malta.

The screw steam sloop Greyhonnd, 17, at Devon-
port, was put in commission on Saturday by Capt.
Sterling. She will have a complement of 175 offi-
cers and men, and will receive draughts to-day.
The crew of the screw steam corvette Satellite,
21, Capt. Crofton, at Devonport, were paid off on
Friday in presence of Rear-Admiral Symonds,
Superintendent of Devonport Dockyard. The Sa-
tellite will be placed in the fourth division of the
steam reserve in Hatnoaze.
The iron screw steamship Agincourt, 26, now
alongside the sheer hulk in Hamoaze, received three
of her iron masts on Saturday, and will have the
remaining two stepped to-day.
The sailing frigate Terpsichore, 18, which has
been selected by the Admiralty to be handed over to ,
Mr. Donald M'Kay, of Boston, United States, to be
used by him in the experiments about to be under-
taken for the purpose of showing the value of tor-
pedoes as an agency for destroying vessels of war, is
now alongside the dockyard at Chatham. She has
bseen denuded of the whole of her stores and gear,
as leave her a mere empty shell, in readiness
forbet g moored at the end of the harbour, where
se:o
the trials are to take pace, care being taken to
place the vessel at such
spot 'that accidents may
be avoided. To testtheaspot
value of the torpedoes 30
of them will be placed under the frigate and dis-
charged, these consisting of six. large and 24 m
shells, which are now in course of manufacture
the purpose. The test shell will be planted in the
mud, below the vessel's keel, 48 hours before explod-
ing. Eighteen of the smaller torpedoes will be
charged with 601 b. of powder, and six with 751 b.
each ; the six large torpedoes will be charged with
4601 b. weight of gunpowder, the whole being suffi-
cient to destroy the largest iron-clad ship in the
English navy. The powder used for the torpedoes
is the same as that in usefor the ordinary rifle.
Col. C. Rogge, C. 8., of the Royal (late Bengal)
Artillery, one of the members of the Ordnance Select
Committee of Woolwich Arsenal, who died at Ash-
leigh-house, Erith, on the 19th inst., was buried on
Saturday with full military honours. The proces-
sion was composed of all the available troops in
garrison at Woolwich, accompanied by the regi-
mental and divisional bands of music. The remains
of the deceased officer had been previously removed