The Sun.
London, England, 1863-03-26 00:00:00

SEA-GOING SHIELD SHIPS.

Capt. Cowper P. Coles, R.N., yesterday delivered
a lecture at the Royal United Service Institution, in
which he explained the principles and construction
of the cupola or shield ships of which he is the inven-
tor, and some of which are now building as part of
the iron-clad fleet of this country. The chair was
taken by Sir John Pakington, and among the audi-
dience was a large number of naval officers and pro-
fessional men who have devoted themselves to the
study of the reconstruction of the navy.
Capt. COLEs commenced his observations byre-
ference to the fact that on the 29th June, 1860, he
had first explained his views at the United Service
Institution with respect to armour-clad ships, views
which the progress of events had since that time
done much to confirm. The construction of line-of-
battle ships, and indeed of all timber built men of
war might be said to have ceased since that time in
almost all the maritime nations of the world, and
the necessity of providing armour-clad ships to re-
sist the greatly increased weight of shot had been
so far recognised in this country that ships of that
description from 700 to 7,000 tons had been con-
structed. It was, he said, however, still an open
question what was the best form in which these
armour-plated ships should be constructed. The
lecturer very naturally was of opinion that the
shield ships were those which ought to be adopted,
and the improvements which had been made in
their construction were of such a nature as to show
they possessed advantages peculiarly adapted for
sea-going ships of all sizes. When he fret proposed
the cupola ship, it was objected to then that it could
not be masted. By the invention of rigid iron tripod
masts this objection had now been entirely ob-
viated. By this plan, combined with his system of
rigging, a ship would be able to spread half as much
more than a vessel with the ordinary masts and rig.
Referring to a model which was before him, the lec-
turer pointed out how the topgallant masts and
yards could be quickly struck and placed on deck,
and nothing but the tripod masts be left above deck
on going into action. These masts were filled
with Cunningham's patent reefing apparatus, so that
the sails could be taken in from below, or reefed fore
and aft. There was no lower rigging to interfere with
the training power of the shield or deck. The yards
and lower stays could be braced fore and aft, and in
a line with the keel, or the square sail could be set
when under steam. On going into action the topsail
could be furled or taken in without exposing the
men to the fire of the enemy. In the event
of the masts being shot away in action, they and
the yards being of iron, would sink at once, and
thus diminish the risk of fouling the screw. The
iron masts were stronger and more durable than
those of wood, and they were secured in their posi-
tion by being " keyed" to the decks as well as the
bottom and bilge of the ship. The breaking strain
of the Valiant's lower rigging was 400 tons, while
that of the iron tripods Was as much as 700 tons.
These masts, too, being constructed hollow, would
afford additional means of ventilation and thus ren-
der the ship more useful for blockading or other
service in any part of the world. He also proposed
to construct platforms, protected by the lashed ham-
mocks, between the legs of the tripod, which would
afford accommodation for riflemen, who would pick
off boarding parties, and thus render more diffi-
cult the operation of boarding by an enemy.
This description of masts would, from their rigidity,
also withstand much better than ordinary ones the
shock when going stem on to the enemy, or when
striking the shore. In addition to giving an addi-
tional spread of canvas, the sails would bo so well
balanced as to give increased facilities in the steer-
ing and working cf the ship, while the distance at
which he proposed to place the main and mizen and
foremasts would divide more equally the length of the
deck than was the case in the Warrior and other of
our iron-plated ships. The centre of effort in his ship
he would place as nearly as possible to the centre of
flotation. By the use of iron he would also consider-
ably reduce the length of the yards, and would em-
ploy none of greater length than 90ft. es compared
with some of 105 or 110 ft. in other ships afloat.
Ships of the class which Captain Coles advocated
would have the advantage of being always ready for
sea. Nothing would be exposed to the mercy of the
weather that would take any harm. The sails would
be stowed away when the ship was in the harbour,
and the iron masts only would be exposed. These
tripodical masts would not be less valuable for the
mercantile than for the royal navy. They would be
rigid, receiving as they did support from all sides.
Each portion of the structure would, in fact, be
doing its portion of work towards resisting any
strain brought against it, for while one side would
be in a state of tension, the other would be in com-
pression. Clipper ships that made a voyage out to
China and home often required on their return new
sets of masts and rigging, owing to the influence of
change ofclimate. This, however,would not be the case
if iron masts were to be substituted for wooden ones.
Assuming that the adoption of his system of iron
tripod masts would effectually remove objections
urged against his shield ships on the ground of the
difficulty of muting them, the gallant captain next
proceeded to institute a series of comparisons be-
tween his cupola ships and those of the old broadside
class, and claimed for the former greater powers of
offence, defence, greater speed, better sea-going
qualities, and lighter draught of water. Taking in
the first
,instance the offensive powers of the two
classes of ships, he compared the Prince Albert shield
ship, now in course of building at Blackwell, with the
Defense, a broadside iron -clad. The Prince Albert
with a tonnage of only 2,529 tons, threw a broadside
of 1,1201 b., while the Defence, of 3,700 tons, only
threw a broadside of 5601 b., so that with less
tonnage the broadside of the cupola ship
was twice as great as that of the