The Sun.
London, England, 1863-10-28 00:00:00

STAMPED ....bd.

were thrown down their weight tended to break the
hinges and detach them from the ship. Since she
has been at Key ham the ports have all been removed,
and they are now to be hung from the heads of the
port-holes. There is some talk of increasing the
canvas of the Thyai Oak by rigging her ship-like
aft. At present she carries no yards on her mizen
mast, being what may be called bark-rigged. In
consequence probably of the position of the engines
and machinery her mainmast is etepped well
aft, and i;s present position would not perhaps ac-
cord with the application of increased canvas on the
ruizm, which might destroy the balance of the sail-
ing forces. With light winds much spi ed cannot
be got out of the Royal Oak, but when going before
a strong wind she is said to be the fastest ship in
the squadron. When the Warrior was running
with studding sails alow and aloft the Royal Oak
was obliged to drop her topsails to the cap to keep
company with her, The Royal Oak, which is 100
feet shorter than the Warrior and Black Prince,
can stay in about four minutes. In the west it is
considered very remarkable that while the Royal
Oak is furnished in her 'tween decks with two
powerful guns aft, which would be extremely use-
ful when chased, she has none for use forward when
pursuing an enemy. It is true that there are pivot
guns on her upper deck, but no artillerymen could
work these when exposed to the rifles of an oppo-
nent. Perhaps the existence of bow ports might
decrease the efficiency of the Royal Oak as as a ram.
Could not her hawser-holes, which are very capa-
cious, be adapted for bow ports ? This ship has an
iron standing bowsprit, which is considered disad-
vantageous for running down an enemy. The most
important fact connected with the late trial of the
Royal Oak at sea is that which relates to the pre-
sent condition of her iron-plating on and below the
load-line. She is, we believe, the first of the iron
armour-plated wooden ships tried; and her first
trial has in this respect been far from satisfactory.
After the water was let out of the dock Port-Admi-
ral Sir Houston Stewart went to Keyham and in-
spected her, and expressed his surprise and great
regret at her condition. The lowest tier or layer of
her iron plates, which is painted with red lead or
some composition, is all more or less honey-
combed, and partially destroyed by galvanic
action, arising from contact or proximity to the
copper sheathing below. Where the corrosion has
set in pieces of the injured iron can be picked
out with the point of a penknife. The tiers
of plates on each side of iron-cased ships are usually
similar in size. The lowest tier on the starboard
side of the Royal Oak consists of 19 plates; each
plate is about 15 feet long, 3 feet 2 inches deep,
and 41 inches thick. Commencing at the bow, the
first plate has 72 holes or pits in it, varying in
depth from a quarter to half an inch ; the second,
40 holes, ti to 7,-; third, 60 holes, 1 to 1; fourth, 94,
to §6, the a in this plate being very close to the
copper ; fifth, 66, k to 1 ; sixth, 109,1 toy; seventh,
168; eighth, 115; ninth, 188; tenth, 220; eleventh,
176 ; fourteenth, 122 holes, &e. Wherever the
least abrasion or friction has taken place, and the
red lead or composition has been rubbed off from
the surface of the plates, galvanic action is in full
force. This is remarkably evident in one part.
The hook, several feet long, which keeps the acco-
modation ladder in its place,is fastened to the ship's
side by an eye-bolt ; when not in use the end drops
below the level of the sea between plates 11 and 12.
It has been allowed to sway about fore and aft, and
has thus worked off the composition. The action
of the copper has in consequence had full effect here,
a portion of a circular groove exists in each iron
plate, each portion being 2 feet 6 inches long in the
sweep, and about dof an inch in depth. in some
places, just at the junction of the iron with the cop•
per, the edges of the iron plates are corroded for
lengths of 6in., 1 foot, and in one place, under the
quarter, this kind of corrosion extends to a length
of 10 feet. Between the iron plates and the copper
sheathing there is a band of 11 inch deep, appa-
rently of lead, but said to be brass or some metal of
a similar colour, which is covered with thin cep-
per. This intermediate band may have been
pieced there with a view to neutralise the effect of
the copper upon the iron plates ; if so, it has proved
to be useless. It is extraordinary that few if any
of the officers of the Royal Oak were aware
of the existence of this band, and that none
appear to understand for what purpose it is placed
there. Between some of the butts of the armour-
plates a quantity of black liquor has been oozing out
in a stream the whole depth of the sheathing. Its
appearance indicates that a serious galvanic action
is going on inside the plates as well as outside. This
would be effected by the penetration of salt water
between the butts, or from the deck scuppers. In
these observations the Royal Oak's bottom is stated
as being sheathed with copper, although strictly
speaking it is not so. She is sheathed with Muntz's
metal, a composition of copper and zinc. Sometimes
the copper prevails to the extent of 60 per cent. ;
that on the Royal Oak may be taken at 50per cent.
It is, however, as copper that the alloy has affected
the iron plates. There appears to be only one remedy
and that is to cover the bottom of an iron-plated
ship with zinc, but this would involve a more fre-
quent inspection in dock, as zinc fouls so rapidly.
A layer of zinc in place of the upper layer of copper
on the Royal Oak would only have the effect of
*a metal to become foul yet more
causing the Munte
rapidly. It may be stated that all the plates above
the lower layer are apparently free from corrosion;
they are of course out of the water, and have an
exterior coat of black paint. The copper on the
is in an excellent state,
bottom of the ship
and was comparatively clean when the ship
was docked. The condition of the Royal Oak will
form a subject for the serious consideration of the
Lords of the Admiralty. It will be almost neces-
sary to remove some of her lower plates, and this
may lead to the removal of the whole of the lower
tier. If so much damage is done in a few months,
it would be highly imprudent to send her on a
foreign station. When one of the indentations be-
fore referred to amounts in five months to a seventh
of the thickness of the armour-plates, it is evident
that by the external action alone the effectiveness
of the plates would be destroyed in three years or
less, without speculating on the duration of
the fastenings or bolts, as they no doubt would de-
cay and become loosened in much less time. The
Royal Oak was launched at Chatham in March,
1863 ; she was put in commission April 27, and
came out of dock May 12, and has consequently been
five months in the water.
The plates out of which the " glacis" plates which
are to encircle the base of the Royal Sovereign's
turrets on her upper deck are to be made have been
received at Portsmouth yard, and handed over to
the steam factory department to accomplish the
work. This will be one of great difficulty, and will
only be
eventually accomplished, if carried out in
the way now proposed, in the utter destruction of
all the shot-resisting qualities of the plates. The
proposed plan is to take the now perfect masses of
metal in their rough strength, carve them out in all
manner of semi-circular lines, and then plan° thew
down from their inner 51in. thickness of inner edge
to nothing on their outer edge or circunitrrell:t
thus destroying the skin, fibre, and strong!
resisting power, of the metal, and
rdinary 68-
to break up under even the shot ratthiag it certain
of
:enieopersistently
pounder like pottery ware. If this
called the sbie een-
purFued the east will bp, onorinolis► t
13y a rougher
not be finished before March nex •
iron p'ating to form
end simpler disposition theof.ren _
gth may he obtained,
the glade, ten times the sr_
I %lace, Rad ea
with the same amount of deue-u,
of the
.cost, and the worjkusc
part
one-h-an dredth
rite;
pleted in one-thirddoef the time. It is but
department to say that •
as chief
the steam
the vast di erenc '
factory
is fully mare in the two
Inns
and in favourri of the shorter and more
Sovereign._ i 3 but an
• I one. The Royal
econoreica
-enentel ship after all,