The Sun.
London, England, 1866-03-20 00:00:00

Her Majesty's Ship Bellerophon.

Yesterday one of the latest additions to her Ma-
jesty's iron navy, a ship whose merits and demerits
have possibly been more largely discussed than those
of any other in times past or present, commenced
her " competitive examination" for official classifica-
tion as a ship of war by entering upon the first
section of her speed trials over the measured mile
in Stoke's Bay, near Portsmouth.
The measure of the ship's qualifications can only
be taken from the final results of the trials which
commenced yesterday at Portsmouth at the ship's
light draught of water, and which will conclude at
her load line, or sea-going draught of water, when
she is ready to proceed to sea with all her armament,
crew, stores, &c., complete, as has been the casewith
all our other ironclads, from the renowned Warrior
downwards. The orders of the Admiralty are that
the trials of the Bellerophon be made as complete in
every way as may be possible. So far as the ship
was tried on a measured mile course, previous to
sailing from the .Nore, there have been contradictory
statements made. The trial was made on the 22d
of September last, the ship at the time drawing but
16 feet 6 inches of water forward, and 25 feet 5
inches aft, carrying nothing inside her hull but her
engines and boilers, 80 tons of coal for the day's
consumption, and her three lowermasts only shipped.
On that occasion the ship was fitted with a four-
bladed screw, the upper edge of the topmost blade
of which was ten inches above the surface of the
water. The ship thus literally " sat upon her screw,"
and in that position was sent to make an official
trial of her speed over the measured mile ! Any
result obtained under such conditions must neces-

sarily be valueless as giving even an approxi-
mate idea of the ship's speed when in seagoing
trim ; but one great fact was obtained--the proof
that a four-bladed screw was the worst possible
form of propeller for engines designed to attain a
maximum number of 70 revolutions, and the full
power of which could only be developed by
that rate of speed. The revolutions of the
engines consequently only reached a maximum
number of 58.25, and a mean number of 57.83,

the mean pressure in the cylinders being 19-681 b.,
the speed of the ship (a mean of six runs) 13.515
knots, and the indicated horse-power 4,707-876.
The four-bladed screw had a diameter of 23ft. 6in.,
a pitch of 21ft. 81in., and a length of lft.
The results of this trial were precisely what ought to
have been foreseen. The screw locked the engines
at 12 revolutions short of their maximum number,
the power of the engines remained undeveloped, and
the ship only attained a speed of 131 knots, when
she ought to have made 141 at the lowest computa-
tion. The published accounts of this trial raised a
cry of derision from those opposed to the new regime
of the Chief Constructor in the department of the
Admiralty presided over by Rear-Admiral Robin-
son. The four-bladed screw was not so well under-
stood then as at the present time, but its unsuitabi-
lity for quick moving engines was also not only con-
clusively established by this first day with the Bel-

lerophon under full steam, but it was also as clearly

established that a two-bladed screw of the best Grif-
fifth form was the one most suitable, and with that
a very different result in the speed of the ship might
be confidently predicted. The opponents of the
ship laid the entire blame of the ship's failure upon
her submerged plough coulter-shaped bow, with its
in-falling stem ; while those interested in the ship,
and outside admirers, rushed upon the unstable do-
main of Theory in search of Negatire Slip, whom
they denounced as the culprit. The four-bladed
screw, however, was the chief culprit, although the
ship's bow, with its immense wave of water thrown
up and hung upon the nose of the ship's stem, as so
much dead weight, was sadly in fault. Immediately
after the trial the frigate was placed in dock, her

four-bladed screw unshipped, and an improvised
" Griffith" of two blades shipped in its place. A
false head and upper stem of light iron was also
built up in front of the ship's infalling stem from
the beak point below the water line throwing the
curve of the upper part of the stein—above
the hawse-pipes--outwards, instead of inboard, as
it was originally. This has not only vastly improved
the ship's appearance at her bows, but the false stem
serves to split vertically the wave thrown up by the
plough bow and heave it off from the ship's stem.
The Bellerophon, as a plough-bowed ship, does
most undoubtedly raise a tremendous wave in front
of her bows when under full steam, which ordinary
observers cannot but believe must very materially
detract from the ship's speed. Our own Chief
Naval Constructor, who has designed the ship, and
M. Dupuy de Lome, the Chief Constructor of
the Imperial French navy, who has designed the
bows of the Magenta, Solferino, and Belliqueuse on
the same plan, both, however, declare that the wave

of water does not affect the speed of the ship. They
argue that a certain amount of water lies in front
of a vessel's midship section which must be got rid
of, that this water is ploughed up by the submerged
portion of the ship's bows, and that this water exists
thus broken up in the wave in front of the ship's
bows, and is hurrying forward in the direction in
which the ship is moving. The measured mile and
after Channel trials of the Bellerophon ought to
satisfactorily define the soundness or unsoundness
of this theory. The great visible fault of this system
in the Bellerophon has been partially remedied by
the false stem given to her, while the vertical floor
of her bluff bow, combined with the ship's moderate
length, gives her a turning power possessed by no
other single screw steamship in her Majesty's navy of
proportionate tonnage and engine power. In justice
to the designer of the ship, it must be said that if she
only proves satisfactory in speed when tried ready for
sea he will have combined in her the two great qua-
lities of speed and handiness under steam in a man-
ner that has never yet been accomplished or even
attempted. The true speed of the ship yet remains
to be established by her trial at deep-load draught,
independently of the trial of yesterday, although
this latter may foreshadow pretty accurately what
will follow. If the plough bow theory as embodied
in the Bellerophon should prove correct in its prin-
ciple, Mr. Reed's triumph in his peristent advocacy
of it will be great and well-deserved. If it prove
incorrect in some of its main features, Mr. Reed
must modify-his opinions and the form of the bows
of his ships at the same time, extending the latter
and finishing them off less abruptly ; losing, per-
haps, by so doing some portion of their present
handiness, but at the same time allowing his ships
to gain the rate of speed due to their engine-power
and tonnage.
The Bellerophon got under way on Wednesday
and Friday last, and made two preliminary trials of
her machinery under steam, Mr. E. J. Reed, Chief
Constructor of the Davy, and Mr. John Penn, the
designer of her engines, being on board on each
occasion. On Wednesday her engines reached a
maximum of 68 revolutions, with an indicated
horse-power of 5,135, the excess being, over what
was obtained on the ship's trial off the Maplin
Sands, in revolutions of the engines 11, and in in-
dicated power 473 horse. On Friday the revolu-
tions of the engines reached a maximum number of
71i, and the indicated rower 6,035 horse. This was
i enxcess of lir. Penn's requirements requirments in his design
for the engines:
and at the conclusion of the day's
trial that gentleilanan
t?imperodfessin g to be perfectly sa-
tisfied for the first
a long business life,
handed the ship over to thue.riGenrogvernment officials for
them to put her through
h trial of speed on the
following Monday.
taken
by
The frigate weighed her anchor at S
10.30 a.m., and soon afterwards was to the
measured mile course in Stoke's Bay, chargen
of
Captain H. Caldwell, C. 8., eommandincr her ma_
jesty's ship Asia and the Steam Reserve at Ports..
mouth. The officers and officials on board coin_
prised Rear-Admiral Superintendent G. G. 'Welles-
ley ; Mr. A. Murray, Chief Superintending Engi-
neer of Portsmouth dockyard ; Messrs. Ward and
Murdoch, of the dockyard steam factory and re-
serve, to superintend the trial ; the Master Ship-
wright's staff of the dockyard ; and Mr. Willing,
from Chatham yard, who superintended
tthe build-
ing there of the ship. Mr. E. J. Reed, he Chief
Constructor, was also on board, and Mr. John Penn
the maker of the engines, was also again present.
The ship's draught of water was 18ft. 10in. for-
ward, and 24ft. 9in. aft; a mean draught of 21ft.
9k n., and a mean. draught of 2ft, lea than ber eeti-

mated load-line draught. All the ship's spars were
aloft, with topgallantmasts on end, her chain cables
and hempen ones all complete, with her comple-
ment of anchors, &c., 31 tons of water in her tanks,
and 123 tons of coals in her bunkers. On the other
hand, she has yet to receive her guns and their car-
riages, with their ammunition ; her sea stores of all
kinds, has to complete her water to 100 tons, and
her coals to 6-10 tons. The following are the re-
sults of the trials over the measured mile and in
making circles, the safety valve of the engines being
loaded at 301 b., the wind at a force of 3 from
E.S.AV., and the water perfectly smooth :