RIFLED ARTILLERY AGAINST FORT PULASKI
By John C. Whatley
athyriot@hotmail.com
The American Civil War introduced three major warfare innovations: ironclad ships (the Monitor and the Virginia); the submarine (the Hunley); and rifled cannon destruction of coastal fortresses. This last usually gets no more than a footnote, if that, yet it foreshadowed today’s improved artillery and naval guns.
The first rifled cannon reduction was launched against Fort Pulaski, guarding the Savannah River and the port of Savannah, Georgia. Named for Revolutionary hero Count Casimir Pulaski, it still sits on Cockspur Island, a low marsh island splitting the Savannah into two channels. Two prior forts had been constructed there: a palisaded log blockhouse named Fort George (after King George II) built as defense against the Spanish in Florida, and a timber-reinforced earthen fort mounting a guardhouse and artillery pieces named Fort Greene (after Revolutionary hero Nathaniel Greene). The first was torn down; the second was destroyed by a hurricane.
Because the English fleet had landed troops at will during the War of 1812, the United States decided to build 200 fortresses from Maine to Florida to protect major ports. In 1816 the Board of Engineers designed a series of coastal fortresses called the “Third System”. Cockspur was selected as site of the last Third System fort built.
Recent West Point graduate Lt. Robert E. Lee was the engineer assigned in 1829 to raise Pulaski. Lee spent 17 months determining the fort’s location, building the dikes and drainage system, and planning the support structure. He was succeeded in 1831 by Lt. Joseph Mansfield, who finished the fort in 1846. By then the United States was at war against Mexico, England had become an ally, and the Third System had low priority.
FORT PULASKI
Pulaski was to be a twin to Fort Sumter in Charleston Harbor: pentagonal, two-storied with three tiers of guns. But Cockspur could not support such weight and Pulaski was modified into a single-story two-tiered fort. Two layers of subflooring were built atop 70-foot-long pilings driven into the mud. On this the 7½ -foot-thick walls were built, using 25 million bricks. Behind Pulaski’s 48-foot-wide moat, two sides (faces) guarded the north channel, two the south. The top tier of guns was en barbette (on the parapet) and the second tier below fired through the casemate openings (embrasures). Heavy casemate piers and arches backed the fort’s walls. Originally built for 150 guns, Pulaski had only 20 casemate 32-pounders in 1861.
When South Carolina seceded in December 1860, Union Maj. Robert Anderson consolidated his troops at Fort Sumter. Georgia Governor Joseph E. Brown, fearing a takeover of Pulaski by Federal troops, ordered Col. Alexander R. Lawton, commander of the 1st Volunteer Regiment of Georgia at Savannah, to seize Pulaski. The two-person garrison – an ordinance sergeant and the fort’s caretaker – immediately surrendered.
Confederates found the fort neglected: the 32-pounders, mounted on rusted iron carriages, could not be fired; magazines held little powder and few shells; living quarters were uninhabitable; the parade ground was overgrown; silt and marsh grass filled the moat. But by hiring 125 slaves from local rice plantations to repair the fort and to clean the moat, 17 officers and 210 men garrisoned a refurbished Pulaski with 36 guns by October 1861. A telegraph line ran to Savannah, and supply ships regularly docked.
Pulaski as a fortress was considered impregnable. Union Brig. Gen. Joseph Totten, a member of the Board of Engineers who designed the Third System, said Fort Pulaski “could not be reduced in a month’s firing with any number of guns of manageable calibers.” Even Lee told Col. Charles Olmstead, commanding the fort, “They will make it very warm for you with shells from [Tybee Island] but they cannot breach at that distance [1,700 yards].” A contemporary military work noted: “An exposed wall may be breached with certainty at distances from 500 to 700 yards. . . [but at a] distance not exceeding 1,000 yards . . . the quantity of artillery must be considerable, and it will require from four to seven days’ firing.”
But the experts were wrong. New technology had recently arrived in the form of rifled cannon. The stable flight produced by the spin from rifled bores, coupled with the increased range of rifled cannon and the impact effect of conical shot on a target, would render coastal fortresses obsolete.
RIFLED CANNON
Englishman Sir Joseph Whitworth manufactured a breech-loading gun with a distinctive hexagonal twisting bore in the 1850s. The hexagonal ammunition followed the tube when fired, producing spin. Whitworth discovered, though, that length and weight of the shot did not affect the gun. Larger projectiles could be made “by simply increasing the length of the projectile without increasing the diameter of the bore.”
Englishman William G. Armstrong tested his breech-loading rifled gun against a Martello tower at Eastbourne, Sussex, England, in August 1860. Martello towers were shorter lighthouse-style towers mounting guns for coast defense instead of lights for navigation. This tower had 7½-foot-thick brick walls. At 1,032 yards a 4¾-inch 40-pounder, a 6-inch 82-pounder, and a 7-inch 100-pounder opened a breach 24 feet wide. The 40-pounder shot penetrated 4 to 5½ feet. A similar breaching test using 68- and 32-pounder smoothbores at the same range was deemed a failure.
The Prussians tested rifled breechloaders against some obsolete fortifications in September 1860. Lt. Col. A. Ross of the Royal Engineers observed that at 640 yards 27-pound rounds fired by two 12-pounder guns produced a breach 32 feet wide in a 3-foot-thick brick wall and penetrated 15 inches.
In America independent inventors experimented with rifled cannon. West Point graduate Robert P. Parrott, supervisor of the West Point Foundry, patented his cast iron rifled cannon design in 1861. Its thick reinforcing band around the breech guarded against the higher internal pressures when firing rifled ammunition. Parrott’s reinforcing band adhered uniformly because he mounted the barrel horizontally on rollers while spraying water inside to cool it. A soft metal band on the shell forced into the rifling imparted spin at firing.
Rhode Island militia general Charles T. James, a self-educated mechanic, invented a round with a conical top of cast iron. Iron ribs connected the top to an open circular base. A lead sabot and a lubricating greased canvas wrapped the ribs. Gases expanded through the ribs when fired, forcing the lead sabot into the rifling grooves, imparting spin.
Capt. Quincy A. Gillmore, the engineer officer of the Union force sent to close Confederate ports along the South Atlantic coast, was familiar with these rifled weapons. He became convinced that rifled artillery could reduce even fortresses such as Pulaski. When Union troops captured Tybee Island, across the South Channel of the Savannah from Pulaski, Gillmore was put in charge of troops there to set up breaching batteries.
Tybee, another Georgia marsh island, has little solid ground. When the cannon arrived, they were hauled by hand from the beach across the flat marshland to their emplacements. All work was done by night and camouflaged before morning. The Confederates heard noise by night, but saw nothing by day.
EFFECT ON PULASKI
On the morning of April 10, 1862, the bushes on Tybee had been cut down and a camouflaging sand ridge leveled. The Confederates saw black objects which they suspected were cannon. When a boat under a flag of truce rowed from Tybee to Pulaski carrying the formal demand for surrender, Olmstead politely replied that he was there “to defend the fort, not to surrender it.” A mortar arched the first shot, the Union cannon joined in, and the Confederates replied.
“Very early in the day however,” Olmstead wrote, “it was seen that the effect upon the fortification was becoming disastrous. . . . [The] rifled guns and Columbiads at the Point inflicted more damage to the Fort than all the others combined.” Firing from the Point were three 10-inch and one 8-inch smoothbore Columbiads in one battery, five 30-pounder Parrotts and one 48-pounder James in the second, and two 84-pounder and two 64-pounder James at the third.
The James shells penetrated the bricks, splitting them from the wall and causing whose sections to collapse. Clouds of reddish dust billowed from the walls at each impact. A shot from one of the Columbiads “struck the wall beneath an embrasure while it was still intact and bulged the bricks on the inside,” wrote Olmstead. “[Our guns] upon the faces fronting the fire that was breaching our walls nearly all were dismounted before the close of the day.”
Olmstead inspected the damage from outside the fort that night. “It was worse than disheartening, the pan-coupe [a short wall between faces] at the south-east angle was entirely breached while above, on the rampart, the parapet had been shot away. . . . The two adjoining casemates were rapidly approaching the same ruined condition; the moat was nearly filled with masses of broken masonry, as was the interior of the three casemates where the dismounted guns lay like logs among the bricks.”
The next morning “the breach rapidly became wider and the enemy’s shot and shell played freely through it across the parade upon the opposite interior angle where the principal service magazine [containing 44,000 pounds of powder] was located. The entrance to this was protected by a large traverse sufficiently heavy, it was thought, for the purpose designed. Between one and two o’clock in the afternoon, however, a shell passed through the top of this and exploded in the passage way, filling the magazine with smoke and lighting it up with flame.”
It was evident that a second similar shot would blow up the fort. The white flag was run up. “There are times when a soldier must hold his position ‘to the last extremity,’ which means extermination, but this was not one of them,” wrote Olmstead. After the surrender another round was discovered stuck in the middle of new brickwork closing the ventilation hole to the southwest magazine.
A corporal of the Phoenix Riflemen and a signalman, escaping the fort before surrender, reported to Savannah: “At the close of the fight . . . the casemate walls [were] breached in almost every instance to the top of the arch, say between five and six feet in width. The moat outside was so filled with brick and mortar that one could have passed over dry shod. The officers’ quarters were torn to pieces, the bomb-proof timbers scattered in every direction over the yard, and the gates to the entrance knocked off. The parapet walls on the Tybee side were all gone, in many places down to the level of the earth on the casemates. The protection to the magazine in the northwest angle of the fort had all been shot away; the entire corner of the magazine next to the passageway was shot off, and the powder exposed, while three shots had actually penetrated the chamber.”
CONCLUSION
After the surrender Gillmore rushed over, eager to see the effects on the fort, and Olmstead escorted him around. He found the James 84-pounders had penetrated 26 inches into the walls, and most James shells penetrated at least 18 inches before exploding, causing enormous lateral damage to the brick. One 42-pounder penetrated 12 feet into the traverses between the barbette guns! Olmstead said the fort’s masonry yielded like wood to the James projectiles. “Brick and mortar cannot stand before them.”
But Union commander Maj. Gen. David Hunter realized Pulaski’s true significance: “The result of this bombardment must cause, I am convinced, a change in the construction of fortifications as radical as that foreshadowed in naval architecture by the conflict between the Monitor and Merrimac [Virginia].
“No work of stone or brick can resist the impact of rifled artillery of heavy caliber.”
athyriot@hotmail.com
The American Civil War introduced three major warfare innovations: ironclad ships (the Monitor and the Virginia); the submarine (the Hunley); and rifled cannon destruction of coastal fortresses. This last usually gets no more than a footnote, if that, yet it foreshadowed today’s improved artillery and naval guns.
The first rifled cannon reduction was launched against Fort Pulaski, guarding the Savannah River and the port of Savannah, Georgia. Named for Revolutionary hero Count Casimir Pulaski, it still sits on Cockspur Island, a low marsh island splitting the Savannah into two channels. Two prior forts had been constructed there: a palisaded log blockhouse named Fort George (after King George II) built as defense against the Spanish in Florida, and a timber-reinforced earthen fort mounting a guardhouse and artillery pieces named Fort Greene (after Revolutionary hero Nathaniel Greene). The first was torn down; the second was destroyed by a hurricane.
Because the English fleet had landed troops at will during the War of 1812, the United States decided to build 200 fortresses from Maine to Florida to protect major ports. In 1816 the Board of Engineers designed a series of coastal fortresses called the “Third System”. Cockspur was selected as site of the last Third System fort built.
Recent West Point graduate Lt. Robert E. Lee was the engineer assigned in 1829 to raise Pulaski. Lee spent 17 months determining the fort’s location, building the dikes and drainage system, and planning the support structure. He was succeeded in 1831 by Lt. Joseph Mansfield, who finished the fort in 1846. By then the United States was at war against Mexico, England had become an ally, and the Third System had low priority.
FORT PULASKI
Pulaski was to be a twin to Fort Sumter in Charleston Harbor: pentagonal, two-storied with three tiers of guns. But Cockspur could not support such weight and Pulaski was modified into a single-story two-tiered fort. Two layers of subflooring were built atop 70-foot-long pilings driven into the mud. On this the 7½ -foot-thick walls were built, using 25 million bricks. Behind Pulaski’s 48-foot-wide moat, two sides (faces) guarded the north channel, two the south. The top tier of guns was en barbette (on the parapet) and the second tier below fired through the casemate openings (embrasures). Heavy casemate piers and arches backed the fort’s walls. Originally built for 150 guns, Pulaski had only 20 casemate 32-pounders in 1861.
When South Carolina seceded in December 1860, Union Maj. Robert Anderson consolidated his troops at Fort Sumter. Georgia Governor Joseph E. Brown, fearing a takeover of Pulaski by Federal troops, ordered Col. Alexander R. Lawton, commander of the 1st Volunteer Regiment of Georgia at Savannah, to seize Pulaski. The two-person garrison – an ordinance sergeant and the fort’s caretaker – immediately surrendered.
Confederates found the fort neglected: the 32-pounders, mounted on rusted iron carriages, could not be fired; magazines held little powder and few shells; living quarters were uninhabitable; the parade ground was overgrown; silt and marsh grass filled the moat. But by hiring 125 slaves from local rice plantations to repair the fort and to clean the moat, 17 officers and 210 men garrisoned a refurbished Pulaski with 36 guns by October 1861. A telegraph line ran to Savannah, and supply ships regularly docked.
Pulaski as a fortress was considered impregnable. Union Brig. Gen. Joseph Totten, a member of the Board of Engineers who designed the Third System, said Fort Pulaski “could not be reduced in a month’s firing with any number of guns of manageable calibers.” Even Lee told Col. Charles Olmstead, commanding the fort, “They will make it very warm for you with shells from [Tybee Island] but they cannot breach at that distance [1,700 yards].” A contemporary military work noted: “An exposed wall may be breached with certainty at distances from 500 to 700 yards. . . [but at a] distance not exceeding 1,000 yards . . . the quantity of artillery must be considerable, and it will require from four to seven days’ firing.”
But the experts were wrong. New technology had recently arrived in the form of rifled cannon. The stable flight produced by the spin from rifled bores, coupled with the increased range of rifled cannon and the impact effect of conical shot on a target, would render coastal fortresses obsolete.
RIFLED CANNON
Englishman Sir Joseph Whitworth manufactured a breech-loading gun with a distinctive hexagonal twisting bore in the 1850s. The hexagonal ammunition followed the tube when fired, producing spin. Whitworth discovered, though, that length and weight of the shot did not affect the gun. Larger projectiles could be made “by simply increasing the length of the projectile without increasing the diameter of the bore.”
Englishman William G. Armstrong tested his breech-loading rifled gun against a Martello tower at Eastbourne, Sussex, England, in August 1860. Martello towers were shorter lighthouse-style towers mounting guns for coast defense instead of lights for navigation. This tower had 7½-foot-thick brick walls. At 1,032 yards a 4¾-inch 40-pounder, a 6-inch 82-pounder, and a 7-inch 100-pounder opened a breach 24 feet wide. The 40-pounder shot penetrated 4 to 5½ feet. A similar breaching test using 68- and 32-pounder smoothbores at the same range was deemed a failure.
The Prussians tested rifled breechloaders against some obsolete fortifications in September 1860. Lt. Col. A. Ross of the Royal Engineers observed that at 640 yards 27-pound rounds fired by two 12-pounder guns produced a breach 32 feet wide in a 3-foot-thick brick wall and penetrated 15 inches.
In America independent inventors experimented with rifled cannon. West Point graduate Robert P. Parrott, supervisor of the West Point Foundry, patented his cast iron rifled cannon design in 1861. Its thick reinforcing band around the breech guarded against the higher internal pressures when firing rifled ammunition. Parrott’s reinforcing band adhered uniformly because he mounted the barrel horizontally on rollers while spraying water inside to cool it. A soft metal band on the shell forced into the rifling imparted spin at firing.
Rhode Island militia general Charles T. James, a self-educated mechanic, invented a round with a conical top of cast iron. Iron ribs connected the top to an open circular base. A lead sabot and a lubricating greased canvas wrapped the ribs. Gases expanded through the ribs when fired, forcing the lead sabot into the rifling grooves, imparting spin.
Capt. Quincy A. Gillmore, the engineer officer of the Union force sent to close Confederate ports along the South Atlantic coast, was familiar with these rifled weapons. He became convinced that rifled artillery could reduce even fortresses such as Pulaski. When Union troops captured Tybee Island, across the South Channel of the Savannah from Pulaski, Gillmore was put in charge of troops there to set up breaching batteries.
Tybee, another Georgia marsh island, has little solid ground. When the cannon arrived, they were hauled by hand from the beach across the flat marshland to their emplacements. All work was done by night and camouflaged before morning. The Confederates heard noise by night, but saw nothing by day.
EFFECT ON PULASKI
On the morning of April 10, 1862, the bushes on Tybee had been cut down and a camouflaging sand ridge leveled. The Confederates saw black objects which they suspected were cannon. When a boat under a flag of truce rowed from Tybee to Pulaski carrying the formal demand for surrender, Olmstead politely replied that he was there “to defend the fort, not to surrender it.” A mortar arched the first shot, the Union cannon joined in, and the Confederates replied.
“Very early in the day however,” Olmstead wrote, “it was seen that the effect upon the fortification was becoming disastrous. . . . [The] rifled guns and Columbiads at the Point inflicted more damage to the Fort than all the others combined.” Firing from the Point were three 10-inch and one 8-inch smoothbore Columbiads in one battery, five 30-pounder Parrotts and one 48-pounder James in the second, and two 84-pounder and two 64-pounder James at the third.
The James shells penetrated the bricks, splitting them from the wall and causing whose sections to collapse. Clouds of reddish dust billowed from the walls at each impact. A shot from one of the Columbiads “struck the wall beneath an embrasure while it was still intact and bulged the bricks on the inside,” wrote Olmstead. “[Our guns] upon the faces fronting the fire that was breaching our walls nearly all were dismounted before the close of the day.”
Olmstead inspected the damage from outside the fort that night. “It was worse than disheartening, the pan-coupe [a short wall between faces] at the south-east angle was entirely breached while above, on the rampart, the parapet had been shot away. . . . The two adjoining casemates were rapidly approaching the same ruined condition; the moat was nearly filled with masses of broken masonry, as was the interior of the three casemates where the dismounted guns lay like logs among the bricks.”
The next morning “the breach rapidly became wider and the enemy’s shot and shell played freely through it across the parade upon the opposite interior angle where the principal service magazine [containing 44,000 pounds of powder] was located. The entrance to this was protected by a large traverse sufficiently heavy, it was thought, for the purpose designed. Between one and two o’clock in the afternoon, however, a shell passed through the top of this and exploded in the passage way, filling the magazine with smoke and lighting it up with flame.”
It was evident that a second similar shot would blow up the fort. The white flag was run up. “There are times when a soldier must hold his position ‘to the last extremity,’ which means extermination, but this was not one of them,” wrote Olmstead. After the surrender another round was discovered stuck in the middle of new brickwork closing the ventilation hole to the southwest magazine.
A corporal of the Phoenix Riflemen and a signalman, escaping the fort before surrender, reported to Savannah: “At the close of the fight . . . the casemate walls [were] breached in almost every instance to the top of the arch, say between five and six feet in width. The moat outside was so filled with brick and mortar that one could have passed over dry shod. The officers’ quarters were torn to pieces, the bomb-proof timbers scattered in every direction over the yard, and the gates to the entrance knocked off. The parapet walls on the Tybee side were all gone, in many places down to the level of the earth on the casemates. The protection to the magazine in the northwest angle of the fort had all been shot away; the entire corner of the magazine next to the passageway was shot off, and the powder exposed, while three shots had actually penetrated the chamber.”
CONCLUSION
After the surrender Gillmore rushed over, eager to see the effects on the fort, and Olmstead escorted him around. He found the James 84-pounders had penetrated 26 inches into the walls, and most James shells penetrated at least 18 inches before exploding, causing enormous lateral damage to the brick. One 42-pounder penetrated 12 feet into the traverses between the barbette guns! Olmstead said the fort’s masonry yielded like wood to the James projectiles. “Brick and mortar cannot stand before them.”
But Union commander Maj. Gen. David Hunter realized Pulaski’s true significance: “The result of this bombardment must cause, I am convinced, a change in the construction of fortifications as radical as that foreshadowed in naval architecture by the conflict between the Monitor and Merrimac [Virginia].
“No work of stone or brick can resist the impact of rifled artillery of heavy caliber.”
posted by Chuck Demastus at
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