 |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
Early Projectiles and Early Ironclads There were two theories prevalent at the time of the battle
between the CSS Virginia and the USS Monitor as to how
projectiles should be used against the plates of an ironclad ship. One
theory held that the projectile should batter its way through the armor and
wood on the side of an ironclad and let the destructive effects of the
projectile be the splintering and shattering effects of the armor upon the
ship's inhabitants. In naval terms. this is sometimes referred to as
racking. No explosive charge was associated with this type and
artillery bolts or solid round shot are the best examples of this
theory. The other theory was the use of piercing
projectiles which the projectile initially enters the ships armor through
a piercing action and the explodes a charge within the armor or behind the
armor killing and maiming the ship's inhabitants. This was the precursor
to today's armor-piercing artillery shells. Battering projectiles were usually made of cast iron
or wrought iron while piercing projectiles were
made of cast-iron usually some part of which usually the nose had been
rapidly-chilled for better penetration. Steel was rarely used
because of the expense or lack of production facilities.. On March 9, 1862
Gustavis V. Fox, Assistant Secretary of the Navy and Lt. Henry A. Wise, Bureau
of Ordnance, watched the encounter between John Ericsson's Monitor and Virginia (aka.Merrimac) from a small
tugboat in Hampton Roads. Although Monitor nor the Merrimac had been materially injured and it was apparent
that something more powerful than Monitor's 11-inch Dahlgren smoothbore guns
would be required to defeat the Confederate ironclads.. After the battle, the Confederates counted
20 indentations from solid round shot on the Merrimac's armor
after the battle made from the Monitor's massive smoothbore guns.
Each of these 11- inch cannon balls weighed 170 pounds. The
Confederates felt lucky as 41 shots against them were made by the Monitor.
Damage consisted of the breaking only six of the top layer of
plates. Merrimac's armor consisted of 4 inches of iron and 22 inches of
wood. The two layers of 2-inch thick rolled armor plates sloped
at an angle of 35 degrees. At this angle, the iron battering shot from the Monitor simply
shattered upon impact. This type of sloping construction was recommended to the
Confederates by studies of plate penetration made by the British
Admiralty. The Merrimac's battery consisted of ten guns; four
single-handed Brooke rifles, and six 9-inch Dahlgren guns. Two of the
rifles, bow and stern pivots, were 7-inch; the other two
were 6.4-inch caliber, one on each broadside.
The 9-inch Dahlgren gun on each side nearest the furnaces was fitted for firing hot
shot. A few 9-inch shot with extra windage were cast for hot shot. No
other solid shot were on board during the fight. The engines were the same
the vessel had whilst in the United States navy. Early photograph showing
numerous hits to the turret of USS Monitor from CSS Virginia. Problematic
pilot house seen in background and lack of "splash rail" at base
of rotating turret. After observing the Monitor/Merrimac
battle, Assistant Navy Secretary Fox come ashore at Fort Monroe was attracted by an experimental 15-
inch Rodman cannon lying nearby. This obviously was the gun needed to defeat the
Confederates. And by April, 1862, Dahlgren completed a 15-inch gun design to fit the
new 20-foot turrets of the Ericsson designed Passaic-Class ironclads. The
Passaic class were
single-turreted monitors designed as enlarged versions of the original Monitor. As such they were larger in all basic dimensions and incorporated
a number of significant improvements. Among these were the installation of
a permanent stack, a pilot house on top of the turret, permanent standing
ventilators, and an increase in the thickness of the armor of the turret
was 11"; and side was increased to 5". The first 15-inch Dahlgren smoothbore guns were mounted
alongside 11-inch shell guns since the 15-inch guns could not be produced
quickly enough to provide two for each turret. The carriages were made of iron
and the gun ports were so small that the 26.5-inch muzzles could not protrude.
Consequently, a smoke/concussion box was devised as shown in the illustration to protect
the gun crew from the blast of the explosion. Early testing of the Dahlgren 15-inch gun was carried
out in attacks on Fort McAllister, Ga. On January 27, 1863, Commander John
Worden, of Monitor fame, and now captain of the new Passaic-class
monitor Montauk, fired twenty-six 15-inch projectiles at the fort
from a range of 1,600 yards. "The firing
from turret seemed slow and deliberate to those in engine room; the smoke
from guns was forced rapidly into fireroom at each discharge, but was well
diluted with air by the fans, and rapidly passed out through furnaces and
smokepipe, causing no unusual discomfort." Rear Admiral
DuPont commented, "We have obtained valuable
information in the success of the working of the XV- inch gun . . . My own
previous impressions of these vessels . . . have been confirmed, viz.,
that whatever degree of impenetrability they might have, there was no
corresponding quality of aggression or destructiveness as against forts,
the slowness of fire giving full time for the gunners in the fort to take
shelter in the bombproofs." More testing came in April, 1863,
when, the Catskill steamed across the bar into
Charleston Harbor, SC. along with six other Passaic-Class monitors: the Montauk,
Passaic, Patapsco, Nantucket, Nahant, Weehawken and
with the experimental ironclad, New Ironsides and the new double-turret
monitor Keokuk. The fleet was under Admiral DuPont who had been assured
by Assistant Secretary Fox that such vessels could steam into Charleston
Harbor and come out "without impunity". The Confederates has
carefully prepared for this moment. They had placed electric mines in
several places in the harbor and they had moored buoys at proper places to
give themselves accurate ranges and as the union ships came in line with
these buoys, the coastal forts around the harbor fired by batteries with
perfect precision. The Confederates did more harm battering
at the monitors with their 7 inch rifle bolts fired from Brooke guns than with
armor-piercing ordinance. The Keokuk which was the closest to Ft.
Sumter, was struck 90 times; 19 shots pierced her armor at or below the
water-line; both of her turrets were pierced in several places; her
forward gun was disabled early in the contest, and the vessel was with
great difficulty kept afloat till next morning when she sank in 13 feet of
water. The Weehawken
was struck 53 times;; her deck was pierced so that the water ran through
it; her side armor was in one place was shattered to pieces by repeated
hits form the Confederate guns and her turret revolved with difficulty due
to heavy hits. The Passaic was struck 35 times. Early in the
action, shot striking the turret disabled the 11 inch Dahlgren smoothbore,
rendering it useless for the remainder of the engagement, Soon after the
turret was found to be jammed. This was later repaired but the turret
performed irregularly. Her Captain wrote in his report, "A
little after, a very heavy rifle-shot struck the upper part of the turret,
broke all its 11 [ONE INCH THICK] plates,
and then glancing upward, took the pilot house, yet with such force as to
make an indentation of two and a half inches, extending nearly the whole
length of the shot. The blow was so severe as to considerably mash in the
pilot-house, bend it over, open the plates, squeeze out the top, so that
on one side it was lifted up three inches above the top on which it
rested, exposing the inside of the pilot-house and rendering it likely
that the next shot would take off the top itself entirely." The Montauk was struck 14 times but was not
materially injured. The Patapsco, the fourth ironclad in the line,
was struck 47 times and her 8 inch Parrott rifled gun which had been
substituted for the 11 inch Dahlgren smoothbore was silenced at its fifth
discharge. The 15 inch Dahlgren was also able to fire only five rounds
before becoming silenced also. The Catskill was struck 20 times but
was not disabled. The Nantucket was hit 51 times, and its 15 inch
gun was disabled after its 3rd discharge, by shots received in the
port-stopper and turret, driving in the plating, and rendering the gun
useless. Her turret became jammed for a time and her deck and side plates
were heavily damaged. The Nahant was hit 36 times and was badly
mauled. Her turret became jammed and useless after several heavy shot
blows A piece of iron weighing 78 pounds was blown into her pilot house
deranging the steering gear, killing the quartermaster at the helm,
striking down the pilot, and leaving the commander alone in the pilot
house. The vessel was entirely disabled and was forced to drop out of
action, along with the Passaic and the Keokuk. At the end of
half an hour, the Confederates had poured 3500 projectiles on the
attackers, at a rate of 160 shot per minute. Four of the monitors with
damaged turrets had the rivets of the iron armor become dislodged and come
flying off into the turret and this wounded gun crews , disables gun
carriages and jammed turret rotation. The sinking of the Keokuk allowed
the Confederates an opportunity to examine a Federal monitor at first
hand. Confederate Major D. B. Harris reported: "Her
turrets within 41/2 feet of their tops had been pierced by 4 10 inch shot
and one 7 inch rifle shot, and a wrought iron Brooke bolt had penetrated
seven-eights of its length and was stuck in the armor plating."
He also observed that the 10 inch smoothbore round shot appeared to be
just as effective at 900 yards as the Brooke bolts against Federal monitor
turrets. Du Pont's fleet was defeated in a little under an hour.
The fleet had been under the concentrated fire of some of the most
destructive guns of that period. Many of the nine ironclad with were part
of the engagement were repaired and reassigned to the Gulf of Mexico
fleet. Federal and Confederate naval engineers
and ordinance officers soon learned that armor of less than 4 1/2 inch
thickness was very vulnerable to armor punching bolts. Testing was always
underway to develop better punching ordinance. John Brooke, head of
Confederate Naval Ordinance, experimented trying to come up with suitable
armor battering projectiles. He found through exhaustive testing that cast iron
shot generally broke into many pieces when fired against armor. His only other
alternative was to use wrought iron which was deficient in hardness to do much
damage. To overcome this drawback he tapered the nose of his projectiles
slightly at the nose and this had the effect of compressing the metal into the
head of the projectile. Even with this modification, most of the energy of the
projectile was expended in the deformation process (see middle picture to the
left) rather than armor
penetration. Brooke also experimented with a projectile brought
forward by Lucian Hopson of Texas. The nose of the projectile
was in the form of a 3 sided pyramid. The drawback was the iron nose of this
projectile could not be made strong enough to penetrate armor. In September,
1863, Admiral Dahlgren reentered Charleston Harbor with ironclads and exchanged
fire with the coastal forts in which the Hopsen projectile was used. This time
the Confederates did not fair as well and Admiral Dahlgren commented: "The
enemy fired some shots of wedge shape, samples of which were picked up from the
decks of the Lehigh - an absurd practice originating in the brain of some
wild inventor." Brooke's experiments
showed that by reducing the caliber of the projectile, adding rifling and using
a heavy powder charge a flat-headed wrought-iron bolt could be driven through
the thickest armor, provided that it struck squarely and at right angles. The
second series of Ericsson monitors built during the Civil War were
of
the Canonicus
class.
This class was again an improvement in design based on experience gained by both
the original Monitor and the Passaic. The Canonicus was
slightly longer measuring 225 feet in length, but slightly narrower than the Passaic.
This was done to give the new monitors greater performance. In all, nine Canonicus
class monitors were built: Canonicus, Catawba, Mahoptac, Manayunk, Manhattan,
Oneota, Saugus, Tecumseh and the Tippicanoe. Canonicus-class monitor Mahoptac
carried two improved 15 inch Dahlgren smoothbore guns inside an improved
turret in which the smoke/concussion box had been eliminated. More
ventilation was also added. In
armament the Canonicus monitors carried two improved fifteen inch
smoothbore Dahlgrens. The turret gun ports were enlarged to eliminate the
smoke/concussion box and to accommodate the new 16 inch muzzle design. Ventilation,
always a problem aboard monitors, was improved by the installation of more
powerful blowers. Normally,
the crew for firing the 15-inch gun consisted of 14 men, but often only eight
men were preferred as being equally efficient with less crowding. Final
justification for the 15-inch gun came on June 17, 1863 when Weehawken’s cored
shot (An empty hollow interior projectile that it decreased the strain on the
gun and increased the velocity of the shot.) penetrated the Confederate ironclad
Atlanta’s 4-inch armor plating and broke the heavy iron
casting at the top of the pilot house. Surrender occurred after only 15 minutes
of fighting. Three type of
projectile were provided, and the 440-pound solid shot could be fired with
60-pound charges at close quarters, although 50 pounds was the normal charge. Cored shot
of 400 pounds was recommended for use against masonry. The 330-pound
shell contained 13 pounds of powder and was ordinarily fired with a 35-pound
charge. It contained three navy time fuses of 3 1/2, 5, and 7 seconds. In addition to the heavy smoothbores, a few of the monitors were
equipped with the 8-inch 150-pdr. Parrott rifles. Of the Passaic class, Lehigh
and Patapsco had them in place of the 11-inch shell guns, and finally the
11-inch of Passaic was replaced with a 150-pdr. rifle. The twin-turreted
Onondaga also had a 150-pdr. Parrott alongside the 15-inch smoothbore in each
turret. The extra range of the rifles was occasionally useful in reaching
targets unattainable with the smoothbore. During the siege of Fort Fisher, N.C., the Confederates had at
their disposal the latest in British armor-piercing projectiles. The Armstrong
projectile was made of wrought-iron or low steel, with very thick sides
and had rows of brass or copper studs projecting from their sides to fit into
the grooves of the muzzle-loading Armstrong rifled gun . The
"blind" shell had no fuse. The thin oval cap in the nose collapsed
as the shell struck armor plate and the heat generated by the projectile
entering the armor set off an internal powder charge. The sides and bottom
of the shell were thick enough to withstand the explosion. This funneled
the explosion straight forward to blow its way through much like the
modern-day armor piercing shell. Because of the high muzzle velocity of
this shell, the heat generated by the impact was high enough to ignite the
power charge. The explosion of the internal powder was delayed until the
shell entered the armor by use of a woolen bag. It is not known how
successful the Confederates were with this shell, but in all probability
the Federal fleet did not venture close enough to the fort to make them
effective. The Federals also used a limited number of smaller
caliber high velocity rifled projectiles. The best known of these was the
invention of Charles W. Stafford. It consisted of a chilled iron bolt
surrounded by a built-up wooden body. Because of its lightness, the bolt
would reach a very high velocity as it left the gun. The wooden sides
broke away from the projectile as it hit the armor and the small bolt
punched through. Later the central bolt was covered in thin metal. As the Civil War drew to a close, it could be said that
the armor piercing projectiles met with limited success even tough
hundreds of them had been fired. The armor piercing projectile simply did
not punch through armor. But when used in conjunction with battering
projectiles to loosen the armor, the combination of the two was very
effective.
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
he period of the Civil War was
one of a rapidly changing ordnance and naval technology. New ideas and
new materiel were being introduced daily. Both the North and the South grasped
much of the new technology and effectively put it to use to their own
purpose and advantage. As with the early developments in
American longarms, such as, barrel rifling and the
Minie bullet, almost all of the early developments and experiments with vessel
cladding and naval artillery rifling took place in Europe before the Civil War.
Artillery projectiles were classified by their shape as
spherical, (fired from smoothbore guns), or elongated,
(fired from rifled guns). They were also classified by their
construction.
Solid shot (either spherical or elongate) were made of cast iron; shells
(either spherical or elongate) could be made of cast-iron, chilled iron, and
steel had hollow
interiors containing the bursting charge;
