Civil War Field Fortifications
Batteries
Batteries were specialized field works designed to receive and provide a protected firing position for an artillery armament. Although batteries should properly be dealt with as siege works, the conditions of their use during the American Civil War suggest that this form of field fortification was not entirely tied to the reduction of fortified places. To prevent misplaced emphasis on theoretical conditions limiting their practical application to the fortification requirements of specific sites batteries must be dealt with as a separate and quite independent fortification form. While other types of field fortifications could be prepared to receive an artillery armament, batteries were specifically designed for a closely grouped artillery armament. Although batteries could be constructed with a profile resembling that of a major field work, the normal profile of batteries did not include a parapet and ditch that served the double purpose of providing shelter and presenting an obstacle to an assault. The parapet and epaulments provided shelter without being raised high enough to pose a serious obstacle to an assault while the ditch simply served as a convenient source for the soil to construct the parapet and was not usually excavated deep enough to be considered an important obstacle. In the case of sunken batteries the soil to construct the parapet and epaulments was provided by the excavation for the terre-plein and no exterior ditch was necessary.
Standard design parameters were generally used in the construction of batteries to ensure that the parapet and epaulments provided the necessary height and thickness of cover to protect the artillery armament and to make sure that the interior space of the battery provided sufficient room for efficient service of the armament. As with other types of field works, the thickness of the parapet depended upon the weight and duration of enemy fire that the structure might reasonably be required to withstand. A parapet exposed to the fire of field artillery could be between 12 and 16 feet thick; a parapet that had to withstand multiple impacts from heavy siege guns would require a thickness between 16 and 24 feet. The interior space necessary to cover a batteries armament depended on the number of guns or howitzers composing the armament. Each gun was usually allowed a lateral space (measured along the crest of the interior slope) of 14 to 18 feet. Splinter proof traverses, which could be included as necessary to defilade the interior space and limit the effects of shell bursts and accidental explosions inside the battery, were allowed a lateral space six feet. Ten feet was taken as the minimum interval between the guns on each flank and the foot of the epaulments. The width of the terre-plein was generally between 20 and 26 feet, which was sufficient to both allow the guns to recoil freely and provide the gun crews adequate room to serve the guns.*
 |
||
 |
||
Batteries were generally subdivided according to the relation of the the level of the terre-plein to the natural level of the ground. Elevated (or raised) batteries were constructed with the terre-plein at or above ground level. Sunken batteries were constructed with the terre-plein below ground level. Both types of batteries could be prepared to mount their artillery armament en barbette or to fire through embrasures cut through the parapet. The choice between mountings depended on the wisdom of the designing engineer, conditions specific to a battery's site, and the purpose of the armament's fire. Barbette batteries were employed when the armament required a wide field and the ability to traverse to follow moving targets such as river or coastal shipping. In cases where the battery could be expected to receive a significant volume of small arms and counter-battery fire the armament had to be be given the extra protection offered by embrasures.
The characteristics inherent to each type of battery largely determined where and under what conditions each could be used to cover a position. Sunken batteries placed cannon very close to the natural level of the ground and could only be used where the intervening ground to the battery's target was completely unobstructed by inconvenient undulations. During the Civil War sunken batteries were often used as water batteries on ground overlooking the banks of rivers where their artillery armament could engage shipping with plunging fire. In some cases, such as DeGoyler's Battery at Vicksburg and some of the Confederate batteries overlooking the James River, sunken batteries were constructed along the crests of ridge lines where the armament would have a clear field of fire along the forward slope of the hill while gaining an extra measure of protection by converting the ridge into an extension of the batteries' parapets. Elevated (or raised) batteries were probably the most common type of battery constructed during the Civil War. Unlike sunken batteries, elevated batteries could be sited wherever artillery could be placed in position and soil obtained to construct a parapet. The incidence of their use during the Civil War are really quite numerous and varied: elevated batteries were used as defensive field works to cover ground not reached by major field works in the defenses of Washington, D. C., they were used in the siege works at Vicksburg, Petersburg, and just about every other major siege operation. During the Battle of Fredericksburg Federal artillery which advanced into the Rappanhannock River valley opposite the town were covered by rudimentary elevated batteries. This brief sampling can only begin to suggest the many ways that elevated batteries were used as both offensive and defensive field works.
Although casemated batteries are not usually associated with field fortifications, enclosed batteries were occasionally built into field works when it was either desirable or necessary to provide artillery with overhead cover and a more shot resistant medium than the rammed earth of the parapet. In most cases casemates were used in river or coastal fortifications where the battery would be subject to the fire of heavy ship-borne ordnance. Fort Hindman, on the Arkansas River included two casemates, Fort DeRussy on the Red River also contained a casemated battery. The bomb-proof Pulpit in Fort Fisher, at the entrance to Cape Fear River, was originally designed as a casemated battery for six guns. Fort Negley, an badly over-designed work in the Federal defenses of Nashville, also included two casemated batteries. Casemated batteries were generally constructed from very heavy and very solid timbers laid in multiple counter-crossing courses. A narrow embrasure was built into the front and the rear was generally left open to allow air to circulate and ventilate smoke from the structure. In some cases (particularly at Fort Hindman and Fort DeRussy) the roof, which rose to or above the level of the interior crest of the parapet, was overlaid with railroad iron in an attempt to make the structure shot-proof.
Blockhouses Rifle Pits Magazines(Restricted Access)
Contents
Home Page
Major Works
Copyright (c)PEMcDuffie 1997, 1998
* It should be noted that almost every manual that described the interior dimensions necessary for a well constructed battery used a different set of design parameters, but that all included the same or very similar basic features that distinguished the battery fortification form from all other types of field works. In practice battery design was usually determined more by local conditions and availability of materials than theoretical prescriptions. Back to Text.