The Third System of coastal fortification

The era of construction following the War of 1812 was instigated as a direct result of British depredations during that conflict. It had been demonstrated that without adequate coastal fortifications, an enemy who enjoyed control of the sea could land more or less where he liked, and raid far inland. The maritime frontier needed better protection, and the Third System, which developed on the heels of the war, was the first coastal fortification initiative created as a result of an analysis of defense priorities rather than as a knee-jerk reaction to the threat of war.

As the work on the Third System was started in 1817, immediacy was no longer an overriding consideration and attention could be directed at last to the creation of a permanent and truly integrated system of harbor defenses.

During the previous two periods of fortification, plans were prepared by individual engineers based on general guidelines issued by the Secretary of War. What this lacked was some sort of planning body, able to set standards and ensure that the latest developments in fortification design were incorporated in any new structures. This was rectified in 1816, when a board of engineers was formed chaired by the French military engineer Brigadier-General Simon Bernard, who until four years before had served as a brigadier of engineers in the French Napoleonic army. Four military and naval engineers, including the immensely talented Lieutenant-Colonel Joseph G. Totten, assisted him (his other colleagues were Brigadier-General Joseph (i. Swift, the Army Chief of

Third System Fortifications

At Fort Jefferson on the Dry Tortugas, off Florida, the rear of the casemates were linked by an arched gallery leading to the corner bastions of the fort. The sheer physical challenge of transporting millions of bricks to an uninhabited rock in the Gulf of Mexico, then building this complex structure 35 miles from the nearest habitation must have been immense. (Author's Collection)

At Fort Jefferson on the Dry Tortugas, off Florida, the rear of the casemates were linked by an arched gallery leading to the corner bastions of the fort. The sheer physical challenge of transporting millions of bricks to an uninhabited rock in the Gulf of Mexico, then building this complex structure 35 miles from the nearest habitation must have been immense. (Author's Collection)

Forts Jackson and McRee

On the shores of the Gulf of Mexico, coastal fortifications had to be built where they were most needed rather than on sites which were ideally suited to the purpose. Fort Jackson (top) was built in a swamp on the banks of the Mississippi River, where her casemate batteries combined with those in Fort St. Philip across the river to cover the river approaches to New Orleans.The firepower of the main fort was augmented by the small Water Battery to the south-east, shown on the right of this view. Fort McRee (bottom), built to protect Pensacola, Florida was built on sand, one of four brick-built fortifications in the area. Her unusual elliptical design was built to carry 108 guns.

Fort McreeGeneral Simon BernardThird System Fortifications
A 10-inch Rodman mounted on an all-metal casemate carriage. This engraving, probably produced shortly after the war. is almost certainly meant to represent the water battery of Fort Monroe, Virginia. (Stratford Archive)

Engineers, Lieutenant-Colonel William McRee and Elliot, Swift and Elliot later resigned in protest at the government hiring Bernard, a foreign national). This Bernard Board of four experts was charged with producing a fortification plan for the entire U.S. coastline, the selection of suitable sites, and the development of plans for the structures. For the first time, a competent professional body was able to supervise all aspects of coastal fortifications, and in various forms this group would continue to perform these functions until after World War II. Members of the board spent two years touring the entire Atlantic seaboard, as well as the newly acquired coastal regions sites in the Gulf of Mexico, and they presented their findings to the Secretary of War in February 1821.

Their first point was that the U.S. Navy, not the Army, should be the first line of defense in coastal waters. They listed the important naval bases, shipyards and harbors, and proposed means of protecting these strategically important locations through the construction of new fortifications. In addition, they recommended the fortification of several coastal cities, river mouths and entrances to inland waterways, which, taken together, would create a powerful defensive barrier protecting the most vital areas of the coast. The Board also discussed road and water communications along the American coastline, and the employment of the Army and Navy in the event of a coastal attack.1 Of the 40 sites they listed, 17 were deemed of the utmost importance to national security and the Bernard Board urged that defensive measures should be taken immediately in order to safeguard their security. The remaining sites were grouped into two bands of lesser importance. The Secretary of War accepted these recommendations, and approved the Bernard Board's list of the most important sites for new fortification works. The immediate work of surveying and reporting completed, Bernard and his colleagues turned their attention to the development of the various fortifications in their key locations. It was only when this work was under way that they were able to revisit their initial list and create a long-term strategy for the fortification of the remaining 23 sites. Inevitably, construction work ate into the available budget, and, while the major ports and river mouths were fortified, other less important areas remained unprotected, save for the crumbling remains of obsolete First and Second System fortifications. Priority was also given to the newly-acquired territories in Florida, where there were very few defenses, and the Gulf Coast, Louisiana.

I Although the contemporary term "harbor fortification" was frequently used to refer to these sites, modern historians more readily use the terms "seacoast" or "coastal." The author has followed the modern convention by using the term "coastal" throughout this work.

Fort Sumter Lighthouse
When Fort Sumter was captured by the Confederates in April 1861, the new garrison found that one of the unmounted 10-inch columbiad smoothbores on the parade had been sited on an improvised carriage for use as a makeshift mortar. (Stratford Archive)

it is significant that in the 1821 report by the Bernard Board, little mention was made of existing First and Second System fortifications. Bernard saw these as a stopgap, providing a modicum of protection while larger and better-planned Third System fortifications were constructed. This was altered when financial constraints were taken into account, and several of these earlier fortifications were incorporated into tire new construction program, effectively turning the earlier works into full Third System fortifications. Examples where this was done include the defenses built to protect Portland, Maine, Boston, Massachusetts, Annapolis, Maryland and Charleston, South Carolina, to name but a few. In all, 18 Second System fortifications were updated in this manner. In addition, a handful of older foreign forts acquired during the incorporation of Florida and the Louisiana Purchase were also earmarked for replacement or renovation.

Defensive works of the Third System fell into several distinctive groups, from small stand-alone coastal gun batteries to vast fort complexes. Of these, the coastal gun batteries were obviously the easiest and fastest to construct, as well as the least expensive. These works were usually built in areas that were deemed of secondary importance to national security, where the expense of a larger fortification was deemed inappropriate. Others were constructed as a stopgap measure and incorporated into a defensive scheme when a larger fort was built alongside them. Unlike earlier coastal batteries these works tended to be linear, with a single row of up to 20 large guns protected by a stone parapet with a sloping earthen glacis in front of it. Better protected coastal batteries were constructed around a long brick-built casemate. This was covered by a stone roof that protected the works from mortar fire.

A variant of the small coastal battery was the Martello tower, named after the original circular fortification built near Martello in Corsica. A staple of coastal fortification in Europe during the Napoleonic Wars, these structures resembled tall (or sometimes squat) round castle keeps, surmounted by a gun platform capable of carrying heavy ordnance. The smallest works of this kind housed a single heavy gun, but by the time the system was introduced in America the structures had become more complex. The design and style of these secondary fortifications varied widely. The Martello tower built on Tybee Island, Georgia, was squat and circular, with a small upper gun platform capable of taking a single gun. The largest Martello towers were found in Key West where both the East and West Martello towers were built around a central square tower, topped with a platform for four guns. In both cases the tower was protected by what amounted to a significant fort, formed from an angled casemate battery of 12-14 gun positions and rear defensive works, which enclosed the perimeter of the Martello tower itself. These two forts were constructed soon after the start of the Civil War by the Union garrison of Key West, and therefore represent the culmination of a minor but significant sub-group of American coastal fortifications. Although Martello towers were relatively uncommon, for some reason the majority of these structures were built in the South (five of the six were located in Florida, Louisiana and South Carolina, the remaining Martello tower was in New Hampshire).

While these smaller coastal fortifications were impressive, the major part of the Third System program involved the construction of large masonry-built fortifications. The large forts of this type built around the coastline of the Southern States would later play a significant part in the Civil War. Wherever they were located, these substantial fortifications all shared certain characteristics. They were solid, substantial structures, capable of housing an impressive number of artillery pieces protected in well-fortified casemates. These guns were usually emplaced in tiered casemates, surmounted by a terreplein, with a large central parade. They were expensive structures, requiring a significant outlay to build them and a continuing expenditure to maintain them, garrison them and keep them in readiness for war. A constant shortage of both funding and manpower would limit the effectiveness of these great structures from the time they were built until the Civil War, when fiscal constraints were removed. To some extent the lack of resources was anticipated by the Bernard Board, who tried to make their structures as durable as possible and took into account potential problems of coastal erosion, salt-water damage and ease of maintenance during their planning and construction.

The choice of masonry as a building material is another important feature of these fortifications. The choice of masonry fortifications was almost certainly made after the successful completion of trials conducted at Castle Williams. Solid shot fired at close range only chipped the surface of the nine-foot-thick curved curtain of the fort, penetrating less than two inches. Masonry was therefore deemed virtually impervious to solid shot. Similar tests conducted in Europe supported the belief that masonrv-built fortifications were proof against all but the heaviest and most sustained bombardments. An added advantage was that it was relatively resistant to the eroding effects of salt water. For the Bernard Board, this was all the evidence they needed. Third System coastal fortifications would be built from masonry.

Confederate Salt Miners
The interior of Fort Sumter, South Carolina, during a mortar attack at the start of December 1863. By this stage most of the upper works of the fort had been destroyed, and the Confederate garrison used the rubble to enhance the protection of the fort's lower casemate tiers. (Stratford Archive)

Masonry was a versatile material. It permitted the construction of scientifically-designed casemates, with each gun and embrasure housed in its own arched bay. These same arches permitted the building of tiered casemates, an essential feature of the imposing fortifications that appeared during this era. The designer of Castle Williams first conceived the concept of building forts with multiple tiers of casemates in 1807, and the technique was used on a handful of other forts before it became the standard style. The advantage of this design meant that it permitted the deployment of the maximum number of artillery pieces, ensuring that it would be suicidal for any wooden ship to attempt to bombard the fort, or the port it defended. In theory, this was an extreme case of deterrence, where the scale of the battery as much as the physical protection afforded by the brick structure itself made the fort impregnable. These structures were designed to hold their own against entire fleets. Although this never happened in a way that could have been anticipated by the designers, these forts managed to perform well against warships during the Civil War, despite revolutionary changes in warship protection, ordnance and ammunition.

One consideration that the designers had to incorporate in their plans was the possibility that the nature of the fort's armament would change at some future date. It was expected that guns would become bigger and heavier, and, while space needed to be made for these potential changes, the size of the embrasure the guns fired from needed to be kept as small as possible, to minimize the risk of a penetrating hit by an attacker. Joseph G. Totten, who became the Board's expert in casemate design, addressed this problem by designing small embrasures with apertures of less than four feet across. Eventually, he also designed heavy iron shutters, which were designed to minimize the risk of a penetrating hit while a gun was being reloaded. His casemate design also permitted the guns inside them to train to either side, permitting them to engage targets at angles of 30° on either side of their central firing position. Clearly, the greater the distance the guns could train round inside their embrasures and casemates, the greater the number of guns that could engage an enemy at any one time.

Bernard himself heavily influenced the fortification designs the Bernard Board produced. As a French engineer, he had studied the geometric fortification systems designed by the great French military engineer Sebastien Le Prestre, Seigneur de Vauban (1633-1707). These grandiose fortifications had become the basis for later 18th-century and early 19th-century European defensive works, and Simon Bernard drew upon his experience in Vaubanesque design. However, he tempered the scale of the fortifications he designed to suit

Fort Morgan, Mobile Bay. Alabama, photographed from the nearby lighthouse after her surrender to Union forces in August 1864.The damage inflicted on the fort by the Union fleet was concentrated on the upper works, and the southwestern seaward scarp. (Salamander Archives)

Vauban Fortifications Fensives

Mmt.

19th Century Forification

By 1864, Fort Sumter looked less like a fort than a gigantic mound of rubble.The garrison conducted repairs of the fort at night to reduce the risk of being caught in the open by a sudden mortar attack.Traces of the lower tier of casemates can just be seen in the distance. (Stratford Archive)

the requirements of America's budget and coastal geography. Joseph Totten became an early convert to this style of formal fortification, with its protective bastions and moats, ravelins and terrepleins, counterscarps and covered ways. It was the genius of the New F.ngland-born engineer that he was able to amalgamate the new casemate design that he advocated with the imposing geometric defensive systems envisaged by Bernard. When Bernard returned to France in 1832 Totten replaced him as head of the Board, and the French influence continued as the American engineer worked on plans for other polygonal fortifications with scientifically worked out angles of fire.

This said, the first forts produced by the Board were far from symmetrical, but conformed to the particular requirements of the land on which they were built. Fort Monroe protecting Hampton Roads in Virginia was a large hexagonal structure of irregular shape, with a redan to one side and a casemated water battery augmenting its defenses. Work began in 1822 and a garrison protected the site from 1823 until its completion ten years later. Designed to contain over 300 guns, the number was increased to 442 by additional water batteries. Fort Adams, protecting Newport, Rhode Island, was a similar stnicture built between 1825 and 1838, supervised for the most part by Totten himself.

After these first projects were started, a certain similarity of design began to appear. The fortifications designed by Bernard and Totten after 1825 were symmetrical, with multiple tiers of casemates. This system of placing one layer of casemates on top of another led to an increase in the height of fortifications after the design of Fort Monroe and Fort Adams. The first forts designed by the Bernard Board contained bastions in the Vauban style, but this changed through Totten's influence. For him, the artillery armament of the fort was sufficient to deter any close assault, and traditional systems of fortification (as typified by Castillo de San Marcos) were deemed to be largely unnecessary. The result was a general shrinking of bastions, and the replacement of flanking batteries of small guns designed to fire up the length of the moat with fewer, larger pieces. This trend was illustrated by the design of Fort Schuyler, built between 1833 and 1841 to guard the approaches to New York Harbor. The fort was designed with reduced bastions, a symmetrical form, and a two-tiered casemate structure. Generally, the design of large Third System coastal fortifications designed between 1825 and 1832 emphasized the use of bastions, each anchoring one of the five corners of a hexagonal curtain. The hexagon shape was the result of simple mathematics. The guns inside a casemate could traverse a maximum of 60° (30° to each side of a central point). This meant that if the sides of the fort were angled at 72°, the risk of an enemy being able to find a dead zone at the corner of the fort was reduced, as the vulnerable area of frontage was limited to 12°. The more maneuverable guns mounted on the

By 1864, Fort Sumter looked less like a fort than a gigantic mound of rubble.The garrison conducted repairs of the fort at night to reduce the risk of being caught in the open by a sudden mortar attack.Traces of the lower tier of casemates can just be seen in the distance. (Stratford Archive)

terreplein were designed to further protect this dead zone. This said, forts were rarely constructed as true hexagons. Instead, the landward, or least threatened, side of the fortification was flattened by reducing the length of the two angles sloping back towards it. In other words, forts had a distinctive front, side and back. This was seen in the design of Fort Sumter protecting Charleston, South Carolina, and Fort Pulaski, built to protect Savannah, Georgia. Work on both of these fortifications began in 1829, towards the end of Bernard's tenure as head of the Board. Their design also reflects the growing influence of Totten, as both forts lacked projecting bastions, though Fort Pulaski's design included two truncated bastions anchoring each end of its landward curtain. Totten's argument for the lack of bastions was that both forts were deemed to be relatively safe from direct assault due to their geographical location (Fort Sumter was surrounded by water, and Fort Pulaski was built on a marshy island). To safeguard against the remote possibility of an assault, Fort Pulaski was further protected by a series of redans and outer works constructed to protect her landward side. Compared to earlier stnictures, these forts were also more compact, requiring smaller garrisons and making their perimeters easier to defend. Another feature that was instantly noticeable to anyone looking at Fort Sumter was the close proximity of the lower tier of casemate embrasures to the sea. By keeping the guns as low as possible, the likelihood that small boats could sail under the angle of fire of the guns was reduced. This also increased the likelihood of ricocheting lire, where the roundshot skipped across the water like a skimming stone. Given the right conditions this increased the range and effectiveness of the guns. This was another design innovation devised by Totten.

While few large projects were undertaken after Bernard's retirement in 1832, gaps in the coastal defense system led to the building of fortifications in isolated places, the most extreme example being Fort Jefferson, built on the Dry Tortugas 68 miles west of Key West. These designs tested the ability of Joseph Totten, and his success in overcoming the structural and logistical problems incurred in their construction marks him as one of the greatest military engineers of his age. Totten became the real mastermind behind the design of these later forts, and his emphasis on the effectiveness of massed ordnance as a means of protection was taken to new levels with these later forts. His trademark remained the creation of large gun batteries mounted in multiple-tiered brick-built casemates, but in a few cases this density was impossible due to physical constraints. At Fort Jackson,

Third System Fortifications

The interior of Fort Sumter after her abandonment in February 1865. When Union troops occupied the fort, they were amazed that it was still a defensible position. The Confederate garrison extensively repaired this casemate. (Stratford Archive)

Parrott Guns Fort Sumter
A Parrott rifle sited on the terreplein of Fort Pulaski, Georgia. This rifled weapon is mounted on top of a granite plinth, capable of an all-round traverse. (Author's Collection)

protecting the Mississippi River approaches to New Orleans, the swampy ground prevented the creation of a three-tiered casemate structure, as the weight would have led to the fort sinking into the ooze on which it was built. A similar problem faced the engineers who built Fort Pulaski on Cockspur Island, as the muddy ground prevented the construction of a larger, heavier fort. In other places, Totten was free to build his forts the way he liked. Fort Zachary Taylor, protecting Key West, Florida, was built on coral bedrock, permitting Totten to build a three-tired casemate fort. Fort Point guarding San Francisco and Fort Richmond, on New York's Staten Island, were both immense three-tiered structures. Shortly after the end of the Mexican-American War (1846-48), the Bernard Board drafted plans to increase the number of fortified sites around the coast, including minor harbors and coastal inlets into the defensive scheme. This ambitious program involved 182 separate projects, providing protection for virtually every U.S. harbor from the Canadian border of Maine to Texas, the length of the Mississippi River, and 19 locations along the Pacific Coast. Lack of funding prevented the commissioning of any of these works before the start of the Civil War in 1861.

The large coastal fortifications of the Third System were also never fully completed, as lack of funding, manpower or ordnance hindered their progress. For instance, many forts begun during the 1840s still lacked sufficient guns and garrison troops to make them fully effective some 10-15 years later when the United States was torn apart by Civil War. These forts, designed to protect the coastline of the United States against attack by a foreign power, were only tested in anger against fellow Americans. Fortifications built in the Southern states of North and South Carolina, Georgia, Florida, Alabama and Louisiana all played significant parts in the war for control of the Confederate coastline and, for brief periods, they became the focal point of the struggle. When the conflict began in April 1861, many of these fortifications were unready for war and were found to be unsuited to the internecine conflict that raged around them. Totten and his fellow engineers had designed their fortifications to face seaward attacks and many were ill prepared to meet an assault by local secessionist militiamen. To make matters worse, during the months leading up to the first shot being fired the government was reluctant to reinforce their forts in the Southern states, for fear that this could inflame the local population. These partially armed and undermanned fortifications were therefore vulnerable to sudden assault and all but four of these strategically vital works fell into Confederate hands when the war began.

A smoothbore columbiad on a reconstructed wooden casemate carriage.The upper slide carriage is run back as far as the rear chocks of the lower carriage. This was the reloading position of the piece. Note the traversing rails, countersunk into the wooden floor of the casemate. (Author's Photograph)

Wooden Casemate

The interior of the casemate battery of the West Martello Tower, Key West, Florida. Although in a bad state of repair, the sound construction of this late-war brick-built casemate is evident. The building now houses a small museum; part of the Key West Art and Historical Society exhibit. (Author's Photograph)

While Totten was unable to predict the nature of the conflict that blighted the United States in the 1860s, he and his fellow Board members were well aware of technological changes in the design of ordnance. While he still placed his faith in the strength of his masonry-built forts, he was aware that they had proved themselves against solid roundshot fired by smoothbore guns. The coming war would see these structures attacked by far more potent weapons: high velocity rifled guns, firing either solid shot or explosive shell. Both sides placed considerable importance in these forts, and in the contest for control of Confederate ports. Their flaw was that they were designed to oppose fleets of slow-moving wooden warships armed with relatively light and inaccurate ordnance. Within a few years they would face siege artillery, ironclad warships and rifled guns. These impressive coastal fortifications proved to be extremely vulnerable to these new guns, and, despite the best efforts of engineers to overcome their limitations, they proved to be little more than obsolete white elephants.

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Simon Bernard Fortifications

Fort Clinch

Fort Clinch, built on Amelia Island, Florida was designed as a pentagon, with five tower-like bastions. Built to the design of Joseph Totten, it incorporated a detached scarp, (known as "Carnot's Wall," named after Lazare Carnot, Napoleon's Minister for War.This unusual structure protected the exterior slope and the terreplein behind it, and was loopholed for use by defending marksmen. Entry to the narrow walkway on top of Fort Clinch's was provided by four passageways, tunneled through the earthen rampart.The design was unsuitable for larger casemated forts, and In Fort Clinch, the main ordnance battery was concentrated on the terreplein.

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