_Size_. To attain high speed and carry heavy armor and armament,
war-vessels must be of large dimensions. By doubling all the lineal
dimensions of a vessel of given form, her capacity is increased eight
fold, that is to say, she can carry eight times as much weight of
engines, boilers, armor, and guns. Meanwhile her resistance is only
quadrupled; so that to propel each ton of her weight requires but half
the power necessary to propel each ton of the weight of a vessel of
half the dimensions. High speed is probably quite as important as
invulnerability. Light armor is a complete protection against the most
destructive shells, and the old wooden frigates could stand a
long battle with solid shot. But without superior speed, the most
invulnerable and heavily armed vessel could neither keep within
effective range of her enemy, nor run her down as a ram, nor retreat
when overpowered. And a very fast vessel can almost certainly run past
forts, as they are ordinarily situated, at some distance from the
channel, without being hit. Indeed, the difficulty of hitting a moving
object with heavy cannon is so great that slow wooden ships do not
hesitate to encounter forts and to reduce them, for a moving ship can be
so manoeuvred as to hit a stationary fort.
The disadvantages of large ships are, first, great draught. Although
draught need not be increased in the same degree as length, a stable
and seaworthy model cannot be very shallow or flat-bottomed. Hence the
harbors in which very large vessels can manoeuvre are few, and there
must be a light-draught class of vessels to encounter enemies of light
draught, although they cannot be expected to cope very successfully with
fast and heavy vessels. Second, a given sum expended exclusively in
large vessels concentrates coast-defences upon a few points, while, if
it is devoted to a greater number, consisting partly of small vessels,
the line of defences is made more continuous and complete.
_System of Protection_. But the effectiveness of war-vessels need not
depend solely upon their size. First, twice or thrice the power may
be obtained, with the same weight of boilers and machinery, and with
considerable economy, by carrying very much higher steam, employing
simple surface-condensers, and maintaining a high rate of combustion and
vaporization, in accordance with the best commercial-marine practice.
Second, _the battery may be reduced in extent_, and the armor thus
increased rather than diminished in thickness, with a given buoyancy. At
the same time, _the fewer guns may be made available in all directions
and more rapidly worked_, so that, on the whole, a small ship thus
improved will be a match in every respect for a large ship as ordinarily
constructed. Working the guns in small revolving turrets, as by
Ericsson's or by Coles's plan, and loading and cooling them by
steam-power, and taking up their recoil by springs in a short space,
as by Stevens's plan, are improvements in this direction. The plan of
elevating a gun above a shot-proof deck at the moment of aiming and
firing, and dropping it for loading or protection by means of hydraulic
cylinders, and the plan of placing a gun upon the top of the armor-clad
portion of the ship, covering it with a shot-proof hood, and loading it
from below, and the plan of a rotating battery, in which one gun is in a
position to fire while the others attached to the same revolving frame
are loading,--all these obviously feasible plans have the advantages of
avoiding port-holes in the inhabited and vital parts of the vessel, of
rendering the possible bursting of a gun comparatively harmless to the
crew and ship, and of rapid manoeuvring, as compared with the turret
system, besides all the advantages of the turret as compared with the
casemate or old-fashioned broadside system. The necessity of fighting
at close quarters has been remarked. At close quarters, musket-balls,
grape, and shells can be accurately thrown into ordinary port-holes,
which removes the necessity of smashing any other holes in the armor.
Protection at, and extending several feet below the water-line, is
obviously indispensable around the battery of a vessel. It is valuable
at other points, but not indispensable, provided the vessel has numerous
horizontal and vertical bulkheads to prevent too great a loss of
buoyancy when the vessel is seriously damaged between wind and water.
Harbor-craft may be very low on the water, so that only a little height
of protection is required. But it is generally supposed that sea-going
vessels must be high out of water. Mr. Ericsson's practice, however, is
to the contrary; and it may turn out that a low vessel, over which the
sea makes a clean breach, can be made sufficiently buoyant on his plan,
If high sides are necessary, the plan of Mr. Lungley, of London, may be
adopted,--a streak of protection at the water-line, and another
forming at the top of the battery at the top of the structure, with an
intermediate unprotected space. A shot-proof deck at the water-line, and
the necessary shot-proof passages leading from the parts below water to
the battery, would of course be necessary.
Considering the many expedients for vastly increasing the thickness of
armor, the idea, somewhat widely expressed, especially in England,
that, in view of the exploits of Armstrong, Clay, and Whitworth,
iron-protection must be abandoned, is at least premature. The manner in
which the various principles of construction have thus far been carried
out will be noticed in a brief.
_Description of Prominent Iron-Clad Vessels_. CLASS I. Classified with
reference to the protection, the dimensions of the English Warrior
and Black Prince are, length 380 feet, beam 58 feet, depth 33 feet,
measurement 6,038 tons. Their armor (previously described) extends from
the upper deck down to 5 feet below water, throughout 200 feet of the
length amidships. Vertical shot-proof bulkheads joining the side armor
form a box or casemate in the middle of the vessel, in which the 26
casemate-guns, mostly 68-pounder smooth-bores, are situated and fired
through port-holes in the ordinary manner. Their speed on trial is about
14 knots,--at sea, about 12. The Defence and Resistance, of 275 feet
length and 3,668 tons, and carrying 14 casemate-guns, are similarly
constructed, though their speed is slow. All these vessels are built
entirely of iron.
CLASS II. This differs from the first mentioned in having protection all
around at the water-line. The New Ironsides, (American,) of 3,250 tons,
240 feet length, 58-1/2 feet beam, 28-1/2 feet depth, and 15 feet
draught, and built of wood, has 4-1/2-inch solid armor with 2 feet
backing, extending from the upper deck down to 4 feet below water, with
vertical bulkheads like the Warrior, making a casemate 170 feet long, in
which there are sixteen 11-inch smooth-bores and two 200-pounder Parrott
rifles. A streak of armor, 4 feet below water and 3 feet above, runs
from this forward and aft entirely around the vessel. Her speed is 8
knots. The Stevens Battery, (American,) 6,000 tons, constructed of iron
and nearly completed, is 420 feet long, 53 feet wide, and 28 feet deep
from the top of the casemate, and is iron-clad from end to end along the
water-line. As proposed to the last Congress, the central casemate was
to be about 120 feet long on the top, its sides being inclined 27-1/2
degrees from the horizon, and composed of 6-3/4 inches of iron, 14
inches of locust backing, and a half-inch iron lining. Upon the top of
it, and to be loaded and manoeuvred from within it, were to be five
15-inch smooth-bores and two 10-inch rifled guns clad with armor. The
actual horse-power of this ship being above 8,000, her speed would be
much higher than that of any other war-vessel. Congress, declining to
make an appropriation to complete this vessel, made it over to Mr.
Stevens, who had already borne a considerable portion of its cost, and
who intends to finish it at his own expense, and is now experimenting to
still further perfect his designs. The Achilles (English) now building
of iron, about the size of the Warrior, and of 6,039 tons, with a
casemate 200 feet long holding 26 guns, belongs to this class. The
Enterprise, 180 feet length, 990 tons, 4 casemate-guns, and the
Favorite, 220 feet length, 2,168 tons, 8 casemate-guns, are building in
England on the same plan. The Solferino and Magenta, (French,) built
of wood, and a little longer than the Royal Oak, (see Class III.,) are
iron-clad all round up to the main deck, and have two 13-gun casemates
above it.
CLASS III. The Minotaur, Agincourt, and Northumberland, 6,621 tons, and
390 feet length, resembling, but somewhat larger than the Warrior, in
all their proportions, and now on the stocks in England; are built of
iron, and are to have 5-1/2-inch armor and 9-inch backing extending
through their whole length from the upper deck to 5 feet below water,
forming a casemate from stem to stern, to hold 40 broadside-guns. Five
vessels of the Royal-Oak class, 4,055 tons, building in England, 277
feet long and 58-1/2 feet wide, are of wood, being partially constructed
frigates adapted to the new service, and are iron-clad throughout their
length and height to 5 feet below water. They are to carry thirty-two
68-pounders. The Hector and Valiant, 4,063 tons, and 275 feet long, are
English iron vessels not yet finished. They are completely protected,
and carry 30 casemate-guns. All the above vessels are to carry two or
more Armstrong swivel-guns fore and aft. Four vessels of La Gloire
class, (French,) 255 feet long and built of wood, resembling the Royal
Oak, carry 34 guns, and are completely clad in 4-1/2-inch solid armor.
Ten French vessels, of a little larger dimensions, are similarly
constructed. The Galena (American) is of this class as to extent of
protection. The quality of her armor has been referred to.
CLASS IV. _Ships with Revolving Turrets_. The Roanoke, (American,) a
razeed wooden frigate of 4,500 tons, is 265 feet long, 521/2 feet wide,
and 32 feet deep, and will draw about 21 feet, and have a speed of 8 to
9 knots. This and all the vessels to be referred to in this class are
iron-clad from end to end, and from the upper deck to 4 or 5 feet below
the water-line. The Roanoke's plates (solid) are 4-1/2 inches thick,
except at the ends, where they are 3-1/2, and are backed with 30 inches
of oak. She has three turrets upon her main-deck, each 21 feet in
diameter inside, 9 feet high, and composed of 11 thicknesses of 1-inch
plates. Her armament is six 15-inch guns, two in each turret. Of the
Monitors, which are all constructed of iron, two now building are to
be seagoing and very fast, and are to act as rams, like several of the
other vessels described. One of these, the Puritan, is 340 feet long,
52 feet wide, and 22 feet deep, and will draw 20 feet. The armor of her
hull, 10-1/2 inches thick, composed mostly of 1-inch plates and 3
feet of oak backing, projects beyond her sides by the amount of its
thickness, and overhangs, forming a solid ram 16 feet long at the bow.
The whole upper structure also overhangs the stern, and protects the
screw and rudder. This vessel will carry two turrets, 28 feet in
diameter inside, 9 feet high, and 2 feet thick, composed of 1-inch
plates. Each turret contains two 15-inch guns. The other vessel, the
Dictator, is similarly constructed, except that it has one turret, two
guns, and 320 feet length. The upper (shot-proof) deck of these vessels
is 2 feet out of water. The 18 smaller Ericsson vessels, several of
which are ready for service, are 18 inches out of water, of light
draught, and about 200 by 45 feet. Their side-armor, laminated, is 5
inches thick, upon 3 feet of oak. They have one turret, like those of
the Roanoke, and carry one 15-inch gun and one 11-inch smooth-bore, or
a 200-pounder rifle. The original Monitor is 174 by 44-1/2 feet, with
5-inch side-armor, and a turret 8 inches thick, 20 feet in diameter
inside, and armed with two 11-inch guns. These vessels of Ericsson's
design are each in fact two vessels: a lower iron hull containing
boilers and machinery, and an upper scow overhanging the ends and
sides, forming the platform for the turret, and carrying the armor. The
Onondaga, now constructing, is an iron vessel of 222 feet length, 48
feet beam, and 13 feet depth, with 4-1/2-inch solid armor having no
backing, and without the overhanging top-works of the Monitors. She has
two turrets, like those of the Roanoke, and four 15-inch guns. Nearly
all the vessels of Class IV. are without spars, and have a pilothouse
about 6 feet in diameter and 6 feet high on the top of one of the
turrets.
The English Royal Sovereign, 3,765 tons and 330 feet length, and the
Prince Albert, 2,529 tons and the same length, are razeed wooden
vessels. The former carries 5, and the latter 6 of Captain Coles's
turrets with inclined sides, each turret designed for two 110-pounder
breech-loading Armstrong guns. The class of iron vessels constructing to
carry two of Coles's turrets are 175 feet long, having 42 feet beam,
24 feet depth, 17 feet draught, and 990 tons displacement. All these
English vessels are much higher out of water than Ericsson's.
Besides these classes, there is the variety of iron-clad vessels called
turtles, from their shape,--among them, the Keokuk (Whitney Battery)
159-1/2 feet long, with two stationary 11-inch gun turrets,--and a class
of Western river vessels of very light draught and some peculiarities of
construction. The latter resemble the Stevens Battery in the shape and
position of their armor, but carry their guns within their casemates.
The Stevens Battery, the Onondaga, and the Keokuk have independent
screw-propellers, which will enable them to turn on their own centres
and to manoeuvre much more rapidly and effectively in action than
vessels which, having but one propeller, cannot change their direction
without changing their position, and are obliged to make a long circuit
to change it at all. This subject is beginning to receive in Europe the
attention which it merits.