The Sun.
London, England, 1859-09-24 00:00:00

AN AMERICAN GUN80..41

On the 24th of last June the steam gunboa

Seminole, one of the seven vessels last ordered by
Congress, was launched at the Pensacola navy-
yard. • Her model was drawn by Naval Contractor
Porter, whose little daughter christened her. The
Seminole is a barque-rigged steamer of 800 tons
burden. She is (what the newspapers have lately
called" a novelty") built on the genuine gunboat
principle, which means that she can carry a very
heavy armament into shallow water, and combines
strength and room ness with swiftness and compara-
tively small proportions. One of her guns will weigh
no less than 25,0001 b., and is a most destructive
weapon. Besides this, two 32-pounders of 42 cwt.
each will be on board, making the Seminole, when
well manned by export sailors and marines, a
powerful (although somewhat diminutive) anta-
gonist to a ship or fort. The machinery of the vessel
is -of the first class. We examined it minutely at
the Morgan Iron-works on Thursdoy. It consists
of two splendid engines of the " horizontal back-
acting steeple" description, 750 horse power, with
cylinders 50 inches in diameter and 30 inches stroke.
The.pistons are connected with cross heads by two
rods. There are a Purson's patent steam condenser
nearly finished, and two pumps, one for air and the
other for water, worked by projecting arms forged
on the lower piston rods, attached to the machinery.
The boilers, of which there will be two and an
auxiliary one, are Martin's patent, measuring re-
spectively 21 feet 6 inches long (six furnaces) and
18 feet 1 inch long (five furnaces). The "auxiliary"
is smaller than these. Both boilers ore of the same
height—viz., 9 feet 8 inches, and the same depth, 9
feet 3 inches. The propeller will be of brass, a two-
bladed screw, 9 feet 6 inches in diameter, and 17
feet pitch. The total weight of the machinery will
be 301 tons, and the consumption of coal about 22
tons per day. She is expected to make 10 or 11
knots per hour under steam alone, and from 11 to 13
under steam and canvas. The Seminole ranks with
the Narragansett, and is smaller than the other five
steamers of her class in course of construction. The
great perfection of gunboats may be briefly classed
under three distinct heads :-1. They are small, can
carry heavy metal into shallow water, and can move
quickly, being steamers. 2. They are easily manned
and easily equipped for sea at very short notice, be-
sides being handy to execute with alacrity Govern-
mental business and squadron duty requiring a na-
tional vessel, but no display. 3. In line of battle
they are considered on a par with sailing frigates
—first, because they can effectively use at least
three heavy guns at all points of the com-
pass, while presenting an exceedingly small
mark for the enemy's ordnance ; second, they can
"choose the time and tide" for fighting, as circum-
stances may dictate ; thirdly, anticipating defeat,
they can make discretion the better part of valour
by an expeditious retreat. But here end their
commendable attributes. They cannot properly
accommodate a crew and carry provisions to sup-
port it, or coal to fire up with for any considerable
length of time, and the Niagara or Minnesota
would sink one of them every hour. In time of
war, as a modern naval battle would be conducted
principally by steam-vessels of large dimensions,
the only use a gunboat could be put to would be
either to act as a tender to larger craft or to cap-
ture merchantmen. Understanding this, and aim-
ing at superiority fn decisive encounters, the French
are not hurriedly increasing their stock of gunboats.
The steamers Wyandotte and Mohawk, preparing
at the Brooklyn navy-yard for the home station,
are nearly ready to receive their crews. No orders
have been received relating to the outfit of the
Niagara and Susquehannah, or the other vessels
lying in ordinary at the navy-yard.—New York
Times.