The Sun.
London, England, 1866-05-03 00:00:00

Armour-Clad Gun Vessels.

Among the many armour-plated vessels of war that have
been recently launched from the banks of the Thames, the
Clyde, and the Mersey, there is one class that, from its
formidable nature, its possession of great powers of offence
and defence, carried on an exceptionally light draught of
water at a high rate of speed, has attracted a great deal of
attention from naval officers and others interested in per-
fecting the design and construction of ironclad ships of war.
A vessel of this description made her trial trip on the Thames
during the past week, and it was the unanimous opinion of
all on board that not only was the vessel a success in point
of speed, but that also for her tonnage she was unequalled by
any other vessel afloat, turret or broadside-gun vessel, in her
fighting powers. She seems especially suited for coast or
river service, and pre-eminently so for service on the Cana-
dian lakes, to which her length and beam give her admission
by the Welland Canal ; or as a defence for our Australian
harbours and rivers. The Medusa—so the vessel referred
to is named—is an armour-clad gunboat, 190 ft. in length,
36ft. in breadth, with a builder's tonnage of 1,160. Her
hull is built of iron, with eight water-tight compartments,
and is covered in with a i-in. iron-plated deck, on which
is laid the usual wood planking. Round the water-line
of the hull is fixed a belt of armour-plating, 41-in. thick
and 4ft. wide, going completely round the bows and stern
at the same thickness as on the sides. The stem of the
ship is fitted on the "ram" principle, as introduced by the
Chief Constructor of the English Navy, and which on
the coasts or rivers of a country must prove a powerful
weapon of offence in attacking an enemy. In a central
position on the hull is built up a square armour-cased battery,
covered with 4f-in. armour-plating, and pierced with eight
gun ports—two on each broadside, and two at each end, the
latter sweeping the fore and after decks, and firing in a
line with the keel, the lower tills of the gunports on the
broadsides when the vessel is complete is all respects for
sea, being 6ft. from the water-line. This square battery is
54ft. in length by 36ft. in width—somewhat astonishing
dimensions for so small a vessel, and will mount four ten-
ton rifled Whitworth guns, on improved carriages and
slides. The sides of the battery are built up of the outer
4i-in. armour, backed with nine inches of teak, the latter
carrying an inner skin of 1-in. iron. This iron inner skin
is supported by vertical iron frames din. deep and 18in.
apart, secured to the plating by Sin. double Angie
irons, over the latter being laid a 4in. wooden lining inside
all. Through the fore part of the battery rises the pilot-
house, covered with 4.1-in. armour. The engines of the
vessel are of the ordinary direct acting, horizontal descrip-
tion, the cylinders having a diameter of 34in., and the
stroke being 21in. They drive a pair of independently
working screws of 7ft. Gin. diameter, and lift. Gin. pitch,
the distance between their centres being 12ft. In the
Medusa, contrary to previous practice with twin screw
engines fitted on the Thames, the engines throw inwards
—i.e., the two screws work towards each other. Revert-
ing, however, for a moment to the hull of the vessel, it is
necessary to remark here that forward and aft of the
central square battery a light iron bulwark, 3ft. Gin. in
height from the deck, passes round the bow and stern of
the vessel from each side of the battery, and throws down
outwards in action in the same manner as the hinged bul-
works of the Royal Sovereign and our other turret ships.
The draught of water of the Medusa, with all on board
and complete for active service, will be but Mt. forward
and aft ; and this fact, if considered in connexion with the
power of the ship's armament, the size of her battery, and
the extent and completeness of her defensive armour, will
quite sufficiently demonstrate her formidable character.
If we now shortly consider her speed under steam
and her manoeuvring powers, her extraordinary
capabilities of attack and defence will be still
further shown. In putting her over the measured
mile in the Lower hope, the wind during the first run was
blowing with a force of 7, and the last run was completed
in a violent squall. The vessel was heavily rigged as a brig
—temporarily, to carry her out to her destination—and she
drew Tin. beyond her load draught of Bft. from being
crammed with coal and extra stores. Under all these un-
favourable conditions, she realized a mean speed of 10.713
knots. The area of her midship section was 300 square feet
and her hull displacement 1,300 tons. The indicated horse-
power of the engines was 947, the mean revolutions 122,
the steam 251 b., and the vacuum 24in. The temperatures'
below during the time the ship was running the mile were
unusually low, the engine-room thermometer registering
70 and the one in the stokehole 105. In testing the ship's
manoeuvring powers under steam Admiral Sir Edward
Belcher took command of the vessel, and, while the whole
of the experiments were of a highly satisfactory inature,
there was one fact rather unexpectedly arrived at which
was of the greatest importance. We have already said that
the engines of the Medusa work inwards, in lieu of out-
wards, the latter course having previously been the rule on
the Thames. In turning the ship, with both engines work-
ing ahead, it was found that the time occupied by the Me-
dusa in completing a circle was in excess of the time that
a single screw vessel would have occupied under similar
conditions of dimensions and power, whereas with both en-
gines reversed and the ship making a circle " stern first"
the time occupied in doing so was materially decreased, and
in fact approximated to that of a vessel with the screws
working outwards. The reason of this appears obvious
enough. With screws working from each other they deliver
their columns of water clear of the ship in two distinct
columns. Working towards each other their water is thrown
together under the vessel's stern, raising a great disturb-
ance of water, which boils up and lashes the ship's stern,
and thus destroys the steering power of the screws.
This view of the subject is, of course open to correction,
but it was the opinion entertained by several on board the
Medusa who have given great attention to every circum-
stance connected with the developement of the twin-screw
principle. Apart from this drawback, the manoeuvres car-
ried out were, as already stated, very satisfactory,inas-
much as it was proved that, with the bulwarks of the
Medusa thrown down as for action and guns pointed
through the four forward or after ports, a more rapid and
heavy fire could be maintained upon an enemy ahead or
astern than could be effected from any turret-ship of similar
tonnage ; the Medusa also possessing the great advantage
of making her hull the training medium for her guns, by
reversing the action of her screws, without having the
weight of the turret to carry, and the risk of damage to its
complicated revolving machinery.
The Medusa was built by Messrs John and W. Dudgeon,
of Cubitt Town Shipbuilding and Engineering-yard, Mill-
wall, and ha- engines were manufactured by James Watt
and Co. The company on board during the vessel's trial
included the Earl of Caithness, Admiral Sir E. Belcher,
R.N., Admiral Ommanney, R.N., Captains Symonds, Wil-
Messrs. John and Wm. Dulgeon, igeou,
son, and Selwyn, R.N. ;
the builders of the ship; Mr. IL Wollaston Blake and Mr.
Langdon, of the firm of James Watt and Co., the manufac-
turers of her engines, and other gentlemen connected with
iron shipbuilding and marine engineering.

ROYAL COMMISSION ON THE LAWS OF MARRIAGE.
—The commissioners met yesterday at 32, Abingdon-
street. There were present—Lord Chelmsford, Lord
Lyveden, the Right Hon. Spencer Horatio Walpole, M.P.,
Right Hon. the Lord Justice Clerk of Scotland, the Solicitor-
General for Scotland, Travers Twins, Esq., and John Fraser
Macqueen, Esq., Q.C., secretary. Professor Muirhead and
Professor Norman Macpherson (both of the University of
Edinburgh) gave evidence.