Original Source: Haze Gray's DANFS Archive, specifically: http://www.hazegray.org/danfs/civ_ord.txt

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CIVIL WAR NAVAL ORDNANCE
by Eugene B. Canfield

From: Dictionary of American Fighting Ships, Volume III, 1968, Navy Department, Office of the Chief of Naval Operations, Naval History Division, Washington, DC

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On January 8,1847 a relatively unknown lieutenant in his late thirties reported to the Washington Navy Yard for ordnance duty. So slightly was he regarded that the officer in charge received him coldly and put him off for 2 weeks. Yet, soon he and his commanding officer were steadfast friends, and such was his ability that when he was placed in command of the South Atlantic Blockading Squadron in June 1863, he had invented a system of boat howitzers, contributed to the development of the naval lock, created the shell guns and a lesser known series of rifles, designed a 15-inch smoothbore for monitor armament, and even originated a .69 caliber rifled musket. [1] The Lieutenant, of course, was John Adolphus Dahlgren and it is to him more than to any other individual that the Navy owed the proficiency of its Civil War ordnance. Aside from the guns developed specifically for the monitor turrets, three basic categories were used:

(a) Boat guns or howitzers;
(b) Broadside guns; and
(c) Pivot guns.

The general types of guns were shell guns, shot guns, rifles and howitzers. In addition, at least in the Confederate Navy, a few Carronades [2] remained from a bygone era.

Although Dahlgren attended to the design of rifled guns as early as 1856, they were not given the same emphasis as in the army, possibly because of the different conditions and problems met afloat. In any case, most of the rifled guns were the designs of Robert P. Parrott, although Dahlgren rifles as well as those of Sawyer and James saw service. In the Confederacy, many Brooke rifles were used.

While generalizations can be made concerning Civil War ordnance, variation and experimentation was the rule. Small, or even significant differences may be found between two pieces of the same type. In addition, many old or obsolete pieces, especially in the Confederacy, were rifled, banded or otherwise modified by a variety of methods so that they no longer represented a standard class of ordnance. Method of updating also could vary depending upon the foundry and the sophistication of its techniques, the time, and the individuals in charge.

Shell Guns

Although Dahlgren's work on boat guns preceded the shell gun designs, his system of shell guns represents the effort for which he is most famous. However, his shell guns were not the first shell guns to arm U.S. ships, 8-inch guns of 63 and 55 cwt. having been established in 1845. Subsequently, a 10-inch shell gun of 86 cwt. also was brought into service. These guns generally followed the form of the canon-obusier developed for the French Navy by General Henri Joseph Paixhans. Paixhan's initial effort commenced about 1821 and by 1841 the first tube had been cast. Dahlgren wrote, "Paixhans had so far satisfied naval men of the power of shell guns as to obtain their admission on shipboard; but by unduly developing the explosive element, he had sacrificed accuracy and range.... The difference between the system of Paixhans and my own was simply that Paixhans guns were strictly shell guns, and were not designed for shot, nor for great penetration or accuracy at long ranges. They were, therefore, auxiliary to, or associates of, the shot-guns. This made a mixed armament, was objectionable as such, and never was adopted to any extent in France...."

"My idea was, to have a gun that should generally throw shells far and accurately, with the capacity to fire solid shot when needed. Also to compose the whole battery entirely of such guns."

The first draft of the 9-inch shell gun was completed January 8, 1850. Commodore Warrington, Chief of Bureau of Ordnance and Hydrography, approved the building of an experimental model on January 10 and an order was placed on the West Point Foundry. Weight of the gun was about 9,080 pounds and the cast iron was to have a density (specific gravity) not less than 7.230 and tensile strength of at least 33,000 pounds per square inch. This original gun, as can be seen from the figure, had a slightly different form from the later designs and had only a single vent.

On May 21, 1850, the gun was landed at the Navy Yard. Practice with the gun was quite successful and encouraged both Dahlgren and Commodore Warrington. Meanwhile, in May of 1850, Dahlgren refined the 9- inch gun, developing the curvature of the reinforce and adding two vents. Although subsequent designs show minor changes including the use of a single central vent [3] in place of the two side vents, this appears to be the design used during the Civil War.

Design for the 11-inch shell gun was submitted March 24, 1851. By April 30, Commodore Warrington had approved the building of a model by Cyrus Alger of the South Boston Foundry. It appears this first gun was used experimentally for several years and finally burst at the 1959th round July 18,1855. In addition to shells, the gun had fired 655 solid shot.

In some respects, the trial 9-inch gun built in 1857 was even more remarkable. After firing 1,500 rounds of standard 72-pound shell with 10 pounds of powder charge, the gun was successively loaded with shot until 10 shot with a total weight of 903 pounds was reached. With 20 pounds of charge, the overloaded tube finally burst. The 10 shot had filled the bore to within 7 3/4 inches of the muzzle.

In 1854, Congress authorized the Secretary of the Navy to build six first-class steam frigates. These six were the famous Merrimack class [4] and Dahlgren's new shell guns were to constitute the armament, the 9-inch being adopted for the gun decks. However, the Bureau refused to adopt the 11-inch pivot insisting instead upon a lighter 10-inch pivot. Because Niagara was to carry 11-inch, however, a few 11-inch were included in the initial production order as follows:


9-Inch

10-Inch

11-Inch

Alger & Co., Boston

28

7

7

Parrott, Cold Spring

28

7

7

Knap & Wade, Pittsburg

50

0

0

Anderson, Richmond

    50    

    0    

    0    


156

14

14

Dispute concerning the ability to handle heavy guns aboard ship continued. Finally, in 1857, in order to convince his critics, Dahlgren obtained Plymouth, sloop-of-war, as a "gunnery practice ship." He then replaced the original armament with four 9-inch shell guns, one 11-inch shell pivot gun, two 24-pdr. and one 12-pdr. howitzer, all of Dahlgren design. Also, the 9-inch broadside guns were mounted on the two-wheel Marsilly carriage rather than the four-wheel common carriage. Plymouth's 6-month cruise was completely successful, and the Secretary of the Navy concluded in his 1857 Annual Report that, "The result of the operations of Plymouth seem to dispel all remaining doubt whether the heavy cannon which she carried would be manageable, and not only to justify the previous adoption of such ordnance in the steam frigates recently built, but also to render it expedient to extend this plan of armament." Firing of the 72.5-pound shell from the 9-inch gun could be accomplished once every 40 seconds by an experienced crew.

Vents in all naval guns were 0.2 inch in diameter. Because the vent became enlarged or worn more quickly than other parts of the piece, two were arranged in the Dahlgren shell guns. One was filled with zinc, the other being used until it became sufficiently enlarged to endanger the safety of the piece. It was then filled with zinc and the first one opened. Other times the right vent only was bored, the left vent being unbored or partially bored.

Normally, the 10- and 11-inch guns were used in pivot and the 9- inch in broadside, but there were few exceptions. USS New Ironsides had a broadside battery of 11-inch shell guns mounted on iron carriages and slides somewhat similar to a pivot mounting. At Charleston, she was able to fire the 11-inch guns once every 1.74 minutes for about an hour or once every 2.86 minutes for 3 hours, and it was believed that a rate of 1.33 minutes per round could be sustained for a short time. The 11-guns also formed a part of the armament for many of the monitors.

Shot Guns

In the decade or more preceding the Civil War, a large variety of 32-pdr. shot guns was available for the armament of naval vessels. These essentially were copies of “the last English decree on the subject” and were constructed in 27, 32, 42, 46, 51, and 57 cwt. sizes. [5] A few other sizes may even be found. The most predominant sizes just previous to and during the war were of 27, 32, 42, and 57 cwt. These guns were generally mounted on the four-wheel common carriage and formed a portion of the armament of many ships.

In addition to the 32-pdrs., a 64-pdr. of 106 cwt. was available for mounting as a pivot gun on a slide carriage, though it was nearly obsolete. During June 1864, an 8-inch shot gun of 10,100 pounds and a 9- inch shot gun of 12,000 pounds were designed with a cylindrical chamber, but these guns likely saw little if any service.

Although these tubes were classified as shot guns, were also available and were supplied to ships in appropriate proportions. For the 32-pdr., the shot weighed 32.5 pounds while the shell weighed approximately 26 pounds when filled with 0.9 pound of powder. Firing at a vertical screen 40 feet wide by 20 feet high at a distance of 1,300 yards with a 32-pdr. of 57 cwt., only three out of 10 shots hit the target, two direct and one on ricochet. The average range to first splash was 1,324 yards with deviations from 1,238 yards to 1,383 yards. While not necessarily the firing rate for this particular practice, the long 32-pdr., like the 9-inch shell gun, could be fired once every 40 seconds. Since a 9-inch shell weighed 73.5 pound complete with sabot, it is apparent duties other than lifting and loading the projectile limited the rate of fire for these two pieces. In noting the armament of various ships, the 32-pdrs. of 42 and 57 cwt. are the most prevalent.

Rifles

Most of the rifled cannon used in the Civil War were the product of Captain Robert P. Parrott and the West Point Foundry at Cold Spring, N.Y. The Parrott rifles were first made in 1860 and consisted of a cast iron tube with a wrought iron reinforced band shrunk around the breech. Sizes varied from the 3-inch 10-pdr. to the 10-inch 300-pdr., although none of the latter and few of the former saw naval service. The 30-pdr. was one of the most popular and reliable sizes and was furnished with both truck and pivot carriages, as was the smaller 20-pdr. The 8-inch 150-pdr. was normally mounted in pivot or placed in the monitor turrets, although a Marsilly carriage as well as the more usual pivot carriage was available for the smaller 6.4-inch 100-pdr.

In September 1862, the 100-pdr. was fired from 130 feet at a target having 6 inches of wrought iron armor plates. Penetration was achieved with a 14-pound charge and 70-pound shot. It was also found that the 8-inch Parrott, with 150-pound bolts and only a 16-pound charge could break through but not punch 4 1/2-inch plates.

The heavy 6.4-, 8-, and even 10-inch rifled guns used in both Army and Navy were almost exclusively those of Robert Parrott. The bursting of some of these guns at Charleston, and later at Fort Fisher weakened confidence in the durability of the guns and brought some discredit to his name. In fact, the Parrott guns were quite remarkable. Rodman, Blakely, Brooke, Dahlgren and others who were working to improve the state-of-art all suffered from the bursting of large caliber cannon, especially rifles. The technology to make reliable large caliber weapons did not yet exist, and when it was developed, cast iron was made obsolete.

Another rifle that saw use, especially on some of the river gunboats, was the invention of General Charles T. James. The guns were old army 42-pdr. smoothbores rifled possibly by Ames at Chicopee, Mass., and supplied with 81.25-pound shot or 64.25-pound shell. While the James rifles and projectiles were primarily noted for their performance at Fort Pulaski and Pensacola, they also performed well in naval service.

Heavy rifles for the Confederate Navy were designed by John M. Brooke. They somewhat resembled the Parrott guns in that the cast iron tubes were reinforced by single and later double wrought iron bands shrunk around the breech. Manufacturing was done at the Tredegar works in Richmond or at the Naval Gun Foundry and Ordnance Works, Selma, Ala. The most predominant sizes were the 6.4- and 7-inch, although an 8-inch was also produced. [6] Except under the banding, the tubes were not turned, but remained in the condition in which they left the mold. For the double-banded 7-inch rifle, nine individual bands each 2 by 6 inches were actually used. Six bands made up the inner layer. After the inner layer was turned in the lathe, the three outer bands were put on, "and the gun is again returned to the mill in order to have the exterior of the outer band turned off."

In February 1863 at Drewry's Bluff, Brooke practiced against an armored target composed of four layers of 2-inch plates and 22 inches of timber backing. Using a gun from CSS Richmond, presumably 7-inch, he "broke three layers of plates, so that the pieces came out, and broke the remaining plate and pushed it firmly in the wood . . ." The range was 200 yards and a 25-pound charge was used to propel the 140-pound bolt. However, proof firing was accomplished with a 16-pound charge and a 111-pound bolt. Other weights of projectile including a 102-pound shell were also available. The 6.4-inch guns were mounted on Marsilly carriages while the 7-inch guns were mounted on pivot carriages. Both carriages were essentially the same as those of the Union fleet.

In general, the Brooke rifles, as well as other cannon produced in the Confederacy, were quite subject to evolutionary changes as well as other small differences peculiar to the foundry and sophistication of the workers and their equipment. Consequently, various differences exist between models of the same type.

As might be expected, Dahlgren also became interested in heavy rifled cannon and made computations for a 16,000-pound model in 1856. By 1860, Dahlgren was firing a 50-pdr. with considerable success. Shortly, designs had also been completed for 30-, 80-, and 150-pdr. rifles, although relatively few had been built. The first 80-pdr. was completed August 28, 1861, and place aboard USS Underwriter. USS Hetzel received serial No. 10 which burst spectacularly on February 7, 1862: “At 5:15 rifled 80-pdr. aft, loaded with 6 pounds of powder and solid Dahlgren shot, 80 pounds, burst, in the act of firing, into four principal pieces; the gun forward of trunnions fell on deck, one third of breech passed over mastheads and fell clear of ship on starboard bow, one struck on port quarter, and the fourth piece, weighing about 1,000 pounds, driven through the deck and magazine, bringing up on the keelson; set fire to the ship....” The tube weighed 7,900 pounds.

Dahlgren rifles were cast without trunnions, and the trunnions were supplied by a breech strap attached to the finished casting. As in the shell guns, two vents were present, although only one was completely bored through to the chamber. Very few of the rifles saw service, and most of them were 50-pdrs. Before his system of rifles was perfected, Dahlgren was given other duties as Rear Admiral and commander of the South Atlantic Blockading Squadron.

Armament for the Monitors

On March 9, 1862 Gustavis V. Fox, Assistant Secretary of the Navy and Lt. Henry A. Wise, Bureau of Ordnance, watched the encounter between Monitor and Merrimack from a small tugboat in Hampton Roads. Although Monitor was left in possession of the battleground, neither contestant had been materially injured and it was apparent that something more powerful than Monitor's 11-inch Dahlgren shell guns [7] was required. Coming ashore at Fort Monroe, Fox was attracted by an experimental 15- inch Rodman columbiad lying nearby. This obviously was the needed gun. Therefore, in April, Dahlgren completed a 15-inch design to fit the 20-foot interior of the new Ericsson ironclads. The first 15-inch 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-box was devised as shown in the illustration to protect the gun crew from the blast of the explosion.

Early testing 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 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.”

On February 28, Worden first proved the effectiveness of the 15- inch guns by destroying Confederate steamer Nashville lying aground under the protection of Fort McAllister. The range to the steamer was approximately 1,200 yards; only eight 15-inch shells and six 11-inch shells were required to set the wooden ship afire. Average time for firing the 15-inch gun was a little over 6 minutes with a minimum time of 3 minutes. On other occasions and with other monitors, the average firing time might be as much as 10 minutes.

Captain Drayton of Passaic reported that "pointing was done for both guns with the XI-inch, the port of the other being entirely closed by the concussion box." Furthermore, the smoke or concussion box was nearly knocked down, and the small projection on the cartridge would not enter the chamber so that priming powder had to be used to ignite the charge. Perhaps because of this, half of the 34 original guns had the teat chambers reamed out to parabolic form and the muzzle was turned down to 21 inches, the diameter of the 13-inch gun. [8] Later, for the Canonicus class, the gun ports were enlarged to eliminate the smoke box and the 15-inch guns were redesigned with a 16-inch long muzzle. Canonicus and her sisters carried two 15-inch guns in their turrets.

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. 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 3.5, 5, and 7 seconds.

Final justification for the 15-inch gun came on June 17, 1863 when Weehawken’s cored shot penetrated 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.

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.

Mortars

Mortars were not widely used by naval forces during the Civil War and opinions regarding them were generally controversial. However, the 17,200-pound 13-inch monsters were used in mortar boats on the Mississippi River. Their greatest use was in bombarding Forts Jackson and St. Philip below New Orleans with 8,000 of the 200-pound shells. [9] Most of the shells fell on and about Fort Jackson and, since the fuses were erratic, some of the shells bored 18 to 20 feet into the soft ground before exploding.

Because mortars were usually fired at an elevation of 45 degrees, it was necessary to provide different charges for targets at different ranges. Safety required that the measuring of powder and filling of cartridge bags be done in the magazine. The cartridges were then sent to the mortar in leather passing boxes. Unlike most other cannon where the cartridge bag was placed in the chamber and pierced by the priming wire as it was pushed down the vent, mortar cartridge bags were opened and the powder carefully emptied into the chamber. The cotton bag was then used to wipe off the shell before it was lowered into the bore, and finally was use to wipe out the mortar before sponging. The bags were never returned to the magazine during action as small amounts of loose powder remaining in the bags might fall out on the deck eventually forming a powder train from the mortar to the magazine. The performance of the mortar flotilla is commendable in that no accidents occurred during the 7 days of firing. One schooner, Dan Smith, fired 493 shells. Maximum range to Fort St. Philip was 4,710 yards and required a 23-pound charge against the wind. Best sustained rate of fire was 2 2/3 minutes per projectile, although projectiles could be fired every 5 minutes with greater ease.

Boat Guns and Howitzers

The Navy system of boat guns and howitzers dates from Dahlgren's earliest endeavors at the Washington Navy Yard. He noted that, "The first trial was a little bronze howitzer of my design, of two hundred and twenty pounds, cast in an old brass furnace . . . bored and finished on a lathe." The work was done in 1848. Even before the Civil War, the pieces saw service at various places around the world. One 24-pdr. and eleven 12-pdrs. accompanied Commodore Perry on his expedition to Japan in 1853-54. The Japanese were so impressed they requested and were given one of the howitzers. All the pieces were made of bronze and were of very simple form. They were attached to their boat or field carriages by a loop underneath the tube in a manner similar to the carronade. Three smoothbores were available: light and medium weight 12-pdrs., and a 24- pdr. A 12-pdr. rifle was available along with a 20-pdr. rifle, although the latter is relatively ignored in the ordnance manuals. [10]

The boat-carriage was composed of a bed to carry the howitzer, a slide on which the bed moved in recoiling, and a wooden plate beneath the slide. William B. Cushing's open launch, in which he successfully torpedoed and sank Albemarle, was equipped with a 12-pdr. howitzer on a boat carriage. The howitzer was fired just before the launch bumped over Albemarle's protecting log boom to explode the torpedo.

The field-carriage was made of wrought iron and, in contrast to land service practice, a small wheel was located at the end of the trail to help the carriage over rough ground, for the carriage was to be hauled by sailors rather than horses. In firing, however, the pin of the trail-wheel was removed and the wheel turned upon the trail in order to reduce recoil. No limber was provided since it was not intended that the howitzer would be moved any great distance from the landing place. If movement was necessary, ammunition was slung from the axle or carried in the pouches of the men.

The basic ammunition for the smoothbores was shell, shrapnel or spherical case, and canister. Shot was never provided. The medium 12- pdr. with its field carriage weighed less than 1,250 pounds, and considerably less than the 2,355-pound army 12-pdr. Napoleon with carriage. Consequently, it could be maneuvered relatively easily by hand, but was not expected to be subjected to as severe an environment as the army field gun. Canister could be fired at a maximum rate of eight rounds per minute although one round in 15 to 18 seconds was typical. On the boat-carriage in a launch, maximum firing rate was approximately five rounds per minute.

Projectiles and Fuzes

The number and variety of projectiles for Civil War ordnance are legion. Many varieties were supplied without official sanction, especially for the rifles. Most spherical shells were fitted with the Navy time-fuse, consisting of a composition driven in a paper case and then inserted in a metal stock which screwed into a bouching fitted to the shell. The fuse composition was covered with a water cap to prevent the flame from being extinguished as the projectile ricocheted over the water. A simple labyrinth was filled with mealed powder to communicate fire to the fuse composition. Protection from moisture and accidental ignition was provided by 3 safety cap. Likewise, a safety plug at the bottom of the fuse prevented fire from being communicated to the powder in the shell if the fuse was ignited accidentally. On loading, the safety cap was carefully removed and the shell pushed home with the axis of the fuse along the bore and away from the charge. On firing, the fuse was ignited by the flame coming around and over the top of the shell, the safety plug being dislodged by the shock of discharge. The illustration shows the water cap screwed into a brass fuse plug which in turn as firmly driven into the fuse hole of the projectile. Apparently, this type of fuse also saw service and was similar to the standard sea- coast fuse.

Shells for the 12- and 24-pdr. howitzers and all spherical shrapnel were fitted with the Bormann fuse which also was standard for the army field artillery. Maximum burning time of a little over 5 seconds was approximately correct for a range of 1,200 yards. Face of the fuse was marked in seconds either by Arabic numerals or dots. In operation, a cut was made beside the appropriate time index mark exposing the ring of composition to the flame of discharge. At the desired time, the fire was communicated to the priming magazine which exploded driving its flame into the charge of the shell or shrapnel. In loading the projectile, the fuse was always toward the muzzle with the cut of the fuse up to be certain the composition would be ignited by the flame of discharge migrating over the top of the projectile. If inadvertently the fuse was placed toward the charge, the fuse might be blown in and the projectile would explode as it left the muzzle.

Firing of naval guns was accomplished by means of a percussion lock. Locks were first introduced into the British Navy by Sir Charles Douglas in 1782 replacing the slow-match and other methods of firing. The U.S. percussion lock used during the Civil War dated from approximately 1842 and was patterned after the method of Hidden. For 32- pdrs. and similar pieces, the lock was attached to an oblong mass of metal about the vent called the lockpiece. On shell guns, the hammer was fitted in a slit cut into a lug cast near the vent. The lock was also attached to the Parrott and other rifles.

To fire the piece, a percussion primer in the shape of a 2 1/2- inch-long quill barrel topped with a wafer or flat head was first inserted in the vent. Then the lanyard was steadily and quickly drawn (not jerked) rotating the hammer on its bolt until it was brought down on the vent setting off the percussion primer. Continued pull on the lanyard drew the hammer clear of the vent avoiding the erosion caused by gasses rushing from the vent. To obtain this action, an inch-long slot was cut at the rear of the hammer. In contrast to the locks on small arms, no springs were included in the mechanism.

The hammer for the boat-howitzers was different and simpler than the standard navy lock. Although the lanyard rotated the hammer in the same way, there was no slot. Instead, the hammer remained on the vent, and a perforation through the head minimized erosion as the gasses escaped. However, the face of the hammer was a nipple that could be unscrewed and replaced if erosion became excessive.

Parrott designed and developed a considerable variety of projectiles for the rifles he produced at the Cold Spring Foundry. The base rings which expanded into the rifling on being fired from the piece took many forms. For the larger calibers, the brass ring was cast into a recess provided with numerous toothlike projections to assure that the ring, which gripped the rifling, also rotated the projectile. The blunt noses of the shot, some solid and others hollow, were hardened and chilled to make them more effective for armor piercing. Against armor, ordinary cast iron shot would become mashed and cause little damage.

Both Hotchkiss and Schenkl projectiles were also used in the rifles. The Schenkl projectile consisted of a cast iron body with a cone shaped tail. A papier mache sabot was expanded into the rifling by being forced on the cone by the action of the charge. Projections on the cone insured that the rotary motion was imparted to the projectile. A basic problem with this ammunition was the material for the sabot. Sometimes moisture would swell the paper mache so that the projectile could not be loaded into the piece. Other times, the sabot material was hard and would crumble on firing, permitting the projectile to tumble in flight. [11] However, the Schenkl percussion fuse was quite successful and remained in naval use long after the Civil War. It consisted of a hollow metallic stock containing a plunger held in place by a small screw. On discharge from the piece, the screw would break and the plunger was free to float. On impact, the percussion cap would be set off igniting the primer within the plunger and exploding the shell.

The Hotchkiss projectile consisted of three parts, the body, a cup on the rear of the body, and a lead ring filling the intermediate space. On discharge, the cup would be pushed forward compressing the lead into the grooves. Another feature for projectiles having time fuses was the three longitudinal grooves along the outside to insure passage of the flame to ignite the fuse. Hotchkiss projectiles were generally quite successful, and were relatively free from tumbling. [12]

Along with his other efforts, John Dahlgren also developed a projectile for his rifles. As shown on page 814, the projectile consisted of an iron body with a lead base cast over projections on the rear. Along the middle of the body several ribs were formed. These ribs were inclined slightly to the axis of the projectile so that they would be parallel to the rifling and were turned to a diameter 0.02 inch less than the bore of the gun. Their purpose was to provide a relatively small but finished bearing surface for the projectile against the bore of the gun. [13] The groove around the periphery of the lead base was filled with lubricating material. The 80-pdr. Dahlgren rifle that burst aboard USS Hetzel was furnished with Hotchkiss and Cochran projectiles as well as the Dahlgren type.

Confederate Brooke projectiles were diversified in shape and method of producing rotation. The four types shown may be found on drawings with Brooke's signature. Two of the projectiles have raised rings (similar to the bourrelet on modern projectiles) which were carefully turned to the proper dimensions, the remainder of the surface being rough as it came from the mold. These also have the ratchet sabot of bronze or copper. The base of the projectile was usually divided into seven equal sectors with their surfaces inclined to the axis preventing the sabot from slipping on the base. The sabot was secured by a central screw. Another type of ratchet-ring sabot, in which a soft metal ring was cast upon the base of the projectile, was personally designed by Brooke.

A very simple method of making projectiles take the rifling was apparently developed in late 1862 when steel for navy solid shot became scarce. The shot was forged of wrought iron and an annular groove was turned in the base to form a lip. On discharge, the lip expanded into the rifling and the rotation was transmitted to the shot. [14]

Other types of guns and projectiles than herein described were used with varying degrees of success. Information on some types may be found easily while a dearth of information exists on others. Often, especially in the Navy, an element of secrecy existed preventing the publication of dimensions or scale drawings of various weapons. However, the secrecy seemed to have been more a personal attitude on the part of various individuals than an official government directive. Thus, Dahlgren's Shells and Shell Guns published in 1856 doesn't contain a single illustration of either shell or shell gun, although other reasons may also have existed. Nevertheless, range tables are readily available. One of the few statements regarding security may be found in the 1866 Ordnance Manual and warns the reader not "to show or explain to foreigners or others the construction of any fuzes, except so far as necessary for the service of the guns."

The period of the Civil War was one of a rapidly changing ordnance technology. Various lessons learned over a period of several hundred years were still being practiced. Yet, new ideas and new materiel were being introduced daily. Both the North and the South grasped much of the new ordnance technology and effectively put it to use to their own purpose and advantage.

Footnotes

[1] Known as the Plymouth musket, it was a development from the French Carabine a Tige. Ten thousand were in service in

[2] Carronades are short iron guns having relatively little weight for their caliber. They have no trunnions and are fastened to their carriage by a loop underneath in a fashion similar to the Dahlgren boat guns. Carronades were first brought into British service in 1779, the 68-, 42- , 32-, and 24-pounders still being listed as retained ordnance after 1870. The Carronade, named after the Carron Works in Scotland, is somewhat obscure in origin some crediting it to General Robert Melville and others to Charles Gascoigne, manager of the company. In any case, the guns were at first called Gasconades and one may conjecture the possibility of a play upon words, for gasconade, derived from the French Gascons, means a boast or vaunt of something very improbable. CS Ram MANASSAS was armed with a single 24- or 32-pounder Carronade.

[3] Upon the death of Commodore Warrington, October 12, 1851 Commodore Charles Morris was placed in command of the Bureau of Ordnance and Hydrography. Apparently Morris insisted on a single central vent and "would not permit me to have my own vent in my own model of IX-inch and X-inch." After Morris' death in 1856, one of Dahlgren's first acts was “to restore the side vents to all his guns."

[4] Others of the class were Wabash, Minnesota, Roanoke, Colorado, and Niagara. Niagara was built as a large sloop-of-war and strangely was armed exclusively with 11-inch guns.

[5] The British had an even larger variety of 32-pdrs designed by Dundas, Monk, Blomfield and others. A hundredweight, cwt, is 112 pounds. Quotation is from Memoir of John A. Dahlgren by Madeleine V. Dahlgren, Charles L. Webster & Co., 1891. Dahlgren's second wife was quoiting from his notes.

[6] Brooke also designed 10- and 11-inch banded smoothbores.

[7] Monitor's 11-inch shell guns were Nos. 27 and 28 made at the West Point Foundry in 1859. Forty-one cast iron shot weighing approximately 170 pounds were fired with 15-pound charges and hit Merrimack 20 times, breaking six o the top layer o plates. Merrimack's armor was two layers of 2-inch thick rolled plates sloping at an angle of 35 degrees. It was later determined that charges of 30 pounds could be used in 11-inch guns.

[8] Dahlgren actually preferred to arm the monitors with 13-inch guns.

[9] Of the 21 vessels in the mortar flotilla, only 20 had mortars. One mortar schooner was sunk on the second day of firing. Some accounts indicate more than 16,000 shells were fired but calculations based on reports from the mortar flotilla indicate 8,000 is more nearly correct. This is still a phenomenal quantity, representing 800 tons of metal.

[10] The 71st Regiment New York Militia had two Dahlgren boat howitzers at Bull Run. After the battle, these, along with other artillery pieces were listed by the Confederate E. P. Alexander in his report of captured equipment.

[11] A more complete description of Schenkl projectiles and fuzes by the same author is presented in Civil War Times Illustrated, June 1966, page 24.

[12] Henry L. Abbot, commanding the siege artillery at Petersburg, felt the projectile strained the guns and did not like to use it in the larger calibers.

[13] Projectiles of this type generally have been identified as of Confederate origin, probably because Henry L. Abbot found a sample among his collection of Confederate ammunition fired into his batteries at Petersburg. Whether the sample (see Siege Artillery in the Campaigns against Richmond by H. L. Abbot, Washington 1867, plate 6, fig. 66) was copied by the Confederates or was reclaimed U.S. ammunition is unknown. Abbot's inability to recognize the Dahlgren naval projectile is some indication of the lack of communication between the Army and Navy on ordnance matters. Dahlgren's patent No. 32986 is dated Aug. 6, 1861.

[14] The drawings with Brooke's signature are in the possession of the National Archives, One drawing titled "The Ratchet-ring Sabot Designed by John M. Brooke Comndr. CSN" bears the date Nov. 24, 1863. The drawing of the solid wrought iron shot is dated Oct. 8, 1862.