Entrenchments and fortifications
O. E. Hunt, Captain, United States Army
Confederate abatis-collected at Petersburg, to be placed in position against Grant's attack|
The development of the use of earthworks in war between civilized nations has been due to the adoption and increase of power of long-range firearms.
The introduction of the breech-loading rifle, of comparatively recent date, has served to give a still greater impetus to the subject of fieldworks for the protection of the forces engaged, and to-day the spade is second in importance only to the rifle.
“Hasty entrenchments,” as they are known by soldiers, were first used largely in the American Civil War
Even at that time, General Sherman
expressed his belief that earthworks, and especially field-works, were destined to play a conspicuous part in all future wars, since they enabled a force to hold in check a superior one for a time, and time is a valuable element in all military operations.
At the beginning of the Civil War
, the opinion in the North and South was adverse to the use of field-works, for the manual labor required to throw them up was thought to detract from the dignity of a soldier.
The opinion prevailed in some quarters that masked batteries were not devices of civilized warfare; and the epithet of “dirt-diggers” was applied to the advocates of entrenchments.
Expressions were heard to the effect that the difference ought to be settled by “a fair, standup fight, in the open.”
“Self-preservation” as a law of nature, and “necessity,” as the mother of invention, soon impressed themselves, however, on the officers and men confronting one another in the field — the
How the pioneer photographer helped to fortify
The lettering on the wagon curtain, “Photographic wagon, Engineer Department,” explains how the problem of preserving the visual teachings of war was solved for the Union Government.
Vast strides in photography were being made by the pioneers Brady, Gardner, and Captain Poe.
Diagrams and sketches gave place to actual reflections of the engineering problems which were overcome.
Here is the first instance of field-photography for a war department.
This photograph reveals the interior of Union Fort Steadman, in front of Petersburg, and its bomb-proof quarters in traverses.
On the right is a photographic wagon of the Engineer Corps.
The attendant is taking his ease in its shade.
This photographic outfit was maintained for the purpose of keeping an official record of matters of professional engineering interest, and good use was made of it. In the West, Captain O. M. Poe was performing a similar service as chief of photography of the United States Engineer Corps. General John Gross Barnard was General Grant's chief of engineers in the East.
The accompanying set of photographs of fortifications is largely from these sources. |
first maxim dictating that it was better to dig dirt than to stand up and be shot at, and the second quickly pointed the way to make dirt digging effective.
Great necessity and the stern experience of war drove erroneous notions from the heads of the combatants, and before the conflict had progressed far, we find both armies digging trenches without orders, whether in the presence of the enemy or not.
One of the historians of the war has stated that they waited neither for orders, deployment of skirmishers, nor even for formation of lines.
The standing rule, adopted by common consent without a dissenting voice, was that they should proceed with this work without waiting for instructions.
It mattered not that their lines might soon be moved.
A little labor and effort on the soldiers' part at the opportune time often saved a life later.
It was the good common sense of the troops that led them to understand the value of even slight protection.
The high intelligence of the individual American soldier made it a simple matter for him to grasp this fundamental truth of his own accord.
He did not need to be educated to it by his officers; he knew it by instinct as soon as the enemy began firing at him. Nor was the initiative in the matter of seeking both natural and artificial protection caused by his knowledge of the art of war. Certain features of the art came to him instinctively, and this was one of them.
The Confederates made great use of earthworks, and by their aid were able to hold the Federals
, in superior numbers, at half-rifle-shot distance on many hard-fought fields.
On many occasions they extemporized protection and dug themselves into rifle-pits, hid their artillery in gun-pits and behind epaulments on the flanks of their infantry lines, and thus made their positions impregnable.
The rapidity with which adequate protection from rifle fire could be obtained by the use of bayonets, tin cups, knives, and other parts of the equipment which the soldier always had
The Engineer photographer 1864--a captured Confederate fort |
A closer view of the entanglements on Marietta street--Chevaux-de-frise |
with him, early became a surprise to everyone; and it did not take long to discover that a short additional time and a little more work rendered that same pit safe from ordinary direct artillery fire.
In loose soil, a few minutes sufficed to throw up a mound of earth a foot high and fifteen inches in thickness, by about two feet in length, for cover against bullets, and this was often topped by a knapsack.
It was not believed when the war broke out that a man could save his life by lying behind such a slight cover, but before the campaign on the Peninsula
was over, every man of both armies knew it.
The Confederates threw up works on the field of Manassas
immediately after their victory.
The position was well chosen and the entrenchments were very well constructed.
To increase the appearance of strength a number of embrasures were filled with “quaker guns,” so-called by the Federals-being simply logs shaped to resemble cannon and placed in position to deceive the foe. These lines were located and the works thrown up, not with the object of assuming the offensive, but to hold the advantage they had gained until it should be decided what further operations should be undertaken.
Consequently, their entrenchments were for defensive purposes only, as the quaker guns indicated.
The Federal plan of campaign having been decided on, the information reached the Confederates
before the Union
army was started for the Peninsula
, and Manassas
was evacuated immediately.
The quaker guns were still in position when the Federals
took possession of the Manassas
arrived on the Peninsula
, he found that the Confederates
were there ahead of him in sufficient force to place works across from Yorktown
, utilizing, in a large measure, the trace of the old Revolutionary works of Lord Cornwallis, and strengthening the parapets to fulfil the more modern conditions of warfare.
works were built for the same general purposes as the Manassas lines
— for defense.
And they served the purpose admirably, for
Closer still to the Atlanta fort: picket fences to stop Sherman's attack
Picket fences with shaped and molded points, dangerous to the small boy's breeches in times of peace, have been utilized by the Confederates to delay Sherman's men for that fatal instant which loses many lives to a charging line.
These seem proportionately as effective as the chevaux-defrise, in the rear-logs pierced by sharpened spokes and the elaborate ditches and embankments, and palisades constructed in the works all about Atlanta.
Historians have declared that no clear conception of Sherman's remarkable campaign to Atlanta can be had unless the difficult character of the country and the formikleble nature of these artificial defenses are remembered.
Practically every foot of the way from Ringgold to Atlanta was entrenched. |
's army was delayed a month before the Confederates
The preliminary reconnaissances by the Federal
engineers persuaded McClellan
that a regular siege of Yorktown
was necessary, and accordingly strong works were erected opposite those of the Confederates
Emplacements for heavy guns and parapets to protect them were pushed to completion.
Regular siege-works, consisting of “parallels” and “approaches,” were projected.
The Confederates held the position until the last moment, and just as fire was about to be opened on them they abandoned the lines.
By that time the works of defense had assumed almost the proportions of a fortress.
Enormous labor was required to effect this, and, correspondingly, the labors of the besiegers were great.
The low-lying ground of the Peninsula
was under water part of the time from the tremendous rains, and the heavy guns of both armies sank into the mud, and it required tremendous exertions to extricate them.
Yet, without fighting, the purpose of the Confederates
was attained — that of delay; and, while many guns had to be abandoned, the expense was compensated for by the increased preparations of the main Confederate army.
But, notwithstanding the lessons in fortification given both combatants by these operations, the individual soldier did not appreciate, to any great extent, his own responsibility in the matter of entrenchments, since these Yorktown
works were on a large scale and used by the entire masses of men of the hostile armies.
It was in the campaign to follow that the important instruction in the art was to come.
The progress of the Federals
was energetically disputed by inferior numbers in field-works at Williamsburg
, which was not so solidly fortified as Yorktown
A large Fort with six redoubts bar-red the road into the town, but, with the flanks not well protected, the position could be turned, and the Union
troops did not wait to undertake a siege.
, Gaines' Mill
, Seven Pines
, Malvern Hill
, and Harrison
Federal fortifications at Allatoona pass, Georgia
When Sherman's army passed this point — early in June, 1864--entrenching was becoming a fine art with the American armies.
From the battle of New Hope Church, on May 25th, almost every advanced line on either side entrenched itself as spon as its position was taken up. Not to be outdone by their Western comrades, the great armies operating in Virginia also got down and “dug dirt.”
In timber, huge logs were placed in position and covered with earth.
Without timber, the parapets were often made as much as fifteen feet thick, to stop artillery fire.
Even on the march the Western armies found time to make gabions of wattles with marvelous celerity. |
The Typical head-log with skids — Sherman's defense before Atlanta
If a shell drove back one of the head-logs in this photograph, it might crush and maim the soldiers in the trenches but for the skids across the trenches.
The head-log was placed on top of the earth parapet, with a space left under the log to permit the men to fire. |
Landing, the works thrown up by the Federals
were increasingly strong, and the private soldier gradually learned his own individual responsibility in preparing the earth-and-log protection.
In the Seven Days Battles, while they were on the defensive, the Union
troops took advantage of all sorts of protection — woods, rail fences, trees, irregularities of the ground, and houses, but made little use of earthworks.
There were so many of the other forms of protection and time was so precious that earthworks did not figure much in their calculations.
The last scene of the Peninsula
campaign was placed at Malvern Hill
, and Harrison's Landing
, which was strongly fortified.
There was thrown up an improvised fortress where, after several days of victorious pursuit of the Federals
, the Confederates
The system of fortifications in this first campaign paralyzed the offensive movements on both sides, saving first the Confederates
and then the Federals
probably from total defeat, and proving beyond doubt that entrenchments of even the slightest character gave excellent results in defensive operations, but also that they must be constructed “with a celerity that defied the rapid march of the opposing army and with an ability and aptitude that enabled a defender to transform an entire field of battle into an improvised fortress.”
Yet, despite the experiences of this campaign, the lesson was not fixed in the minds of the combatants.
The former schools of military teaching still showed their effects.
In the campaign between Lee
, in 1862, but little use was made of field-works, and at Antietam Lee
fortified only a part of his line, though strictly on the defensive.
evidently taught the lesson anew, for we find that same Confederate army at Fredericksburg
with lines that defied the efforts of the assailants as effectually as permanent fortifications could have done.
The manner of construction of these works of hasty entrenchment usually was this: The men, deployed in a line of
skirmishers, would dig, individually, shallow trenches about four or five feet by two, with their longest dimension toward the foe, and throw up the earth in a little mound of a foot or fifteen inches in height, on the side toward the opponent.
This would result in a line of such excavations and mounds, each individually constructed and without any communication with its neighbors.
Then the neighbors would dig out the ground between them and throw it to the front, thus forming a continuous line of earthern parapet; but, if their antagonists were firing, or danger was near, it was preferable to deepen the trenches and throw up a larger earth protection before joining the individual trenches.
In the rear of such hasty works, heavier lines often were constructed by large forces working with spades.
Semi-permanent works were used both in the East
and in the West
, Forts Henry
, and other small works were all of a permanent or semi-permanent character, having more or less of the scientific touch that followed the old school of fortification.
But little was known in the West
of the art of hasty entrenchments for some time.
, the Federal
camps were not entrenched, although the foe was known to be somewhere in the vicinity.
said that the reason for the lack of field-works was that their construction would have made the new men timid.
As a matter of fact, the value of them was not realized by anyone, except that it was known, of course, that heavy works were capable of withstanding an attacking body several times the strength of the defending force.
But, after Shiloh
took command and erected earthworks nearly every foot of the way from Pittsburg Landing
to Corinth, Mississippi
, a distance of at least twenty miles, and then prepared for a regular siege of the latter place, where his army outnumbered that of Beauregard
about two to one.
His approach took a month, at the end of which time Beauregard
This cautious advance marked the first use of
entrenchments at every halt.
In at least two of the great battles during the preceding period of the war — Bull Run
— no entrenchments to speak of had been used.
, going to the extreme in the other direction, lost valuable time constructing trenches for which a little effort at reconnaissance would have told him there was no use. With such good preliminary preparation we should be prepared to see field-fortifications used everywhere more lavishly.
And we are not disappointed in finding that both parties to the controversy had now learned their lesson.
At Stone's River
, or Murfreesboro
, the Federals
entrenched a part of their extreme left and the Confederates
their right and center before the battle.
On the first day, the Federal
right was driven back, and during the following night the Confederates
entrenched practically all of the remainder of their line.
The net result of the battle was a drawn fight, the opponents not daring to attack each other's works seriously.
A wholesome respect had grown for hasty entrenchments.
The “dirt-diggers” were coming to the front.
The defensive warfare carried on to the end by the Confederates
in the West
placed them most of the time behind their temporary or semi-permanent works.
All the forts along the Mississippi
were, necessarily, of the strongest character, assuming the importance of permanent fortifications, armed with heavy guns and manned by small permanent garrisons and, during Grant
's and Banks
' campaigns, by larger garrisons, pushed in from the field.
All of these stronger places had to be taken by the process of regular siege.
retired from Murfreesboro
, he entrenched several lines between that place and Chattanooga
, but Rosecrans
, by consummate strategic skill, turned him out of all of them without fighting serious battles.
On the battlefield of Chickamauga
, the infantry and artillery of Thomas
' wing of the Federal
army stood “like a rock” behind entrenchments and barricades of earth, fence rails, and logs.
Constructing gabions for Grant's attack on Petersburg
The basket-like objects in this photograph are gabions.
On the top of one row lie sand-bags.
The soldier is seated on three short fascines, and in the background are some long fascines on another row of gabions.
A gabion is a cylindrical basket with no bottom, which may be placed in a fortification and filled with earth.
Gabions make an exceedingly strong defense, since the dirt remains even if the baskets are smashed.
Thousands of gabions were used in the entrenchments of both attacking and defending forces at Petersburg.
Fascines consist of small branches or twigs tied by wire or rope or thongs of some tough vine.
They vary in length according to whether they are to be used in the construction of works or filling in a ditch.
They hold the earth at a steeper slope than the natural slope when the earth is loose.
Gabions are also useful for revetments from their perpendicularity; through sand-bags, a foot or two might be added to their height. |
in the open, was repulsed, but later sat down behind entrenchments in front of Rosecrans
, and almost starved out the Federal
army before it could be relieved.
to drive him off. Hooker
was successful at Lookout Mountain
, but Sherman
did not make any headway against the right of the Confederate army, being checked before the heavy trenches.
' men to take the works at the foot of Missionary Ridge
Because of the Federal
defeat at Chickamauga
, it is reported that Grant
feared that the men of Thomas
' army could not be trusted to stand under heavy pressure, and he did not want them to go farther than the foot of the ridge.
He ordered that they stop there, after driving the Confederates
from the trenches.
But the lines kept on, higher, higher, and the clouds of battle became larger as they ascended.
Seeing the line disobeying orders, Grant
turned to Thomas
, who was near, and inquired by whose orders the men had gone beyond the foot of the mountain, to which Thomas
is said to have replied, “By their own, I think.”
's rejoinder was: “If they succeed, all right.
But if they don't, some one will suffer for this.”
The works at the top were heavy; but Thomas
' troops succeeded, and no one suffered except the gallant men of both sides who fell.
went East, turning over the command of the Western Federal
armies to Sherman
, who prepared to attack Johnston
, entrenched around Dalton, in northern Georgia
's Roost formed the strongest portion of Johnston
's line, which consisted of heavy fortifications on the heights, in front of which lighter lines had been placed.
felt this position, found it almost impregnable, made a flank movement, and turned Johnston
out of his stronghold.
In the retaining attack on the works, the Federal
troops took a portion of the lower lines of entrenchments, but found the upper works too strong.
The turning movement having succeeded, the Union
troops withdrew from the front, and Johnston
, and thence to succeeding positions until Atlanta
Direct assaults on entrenchments nearly always failed with heavy loss.
By this time it was thoroughly understood that the function of breastworks, whether of earth, logs, rails, or other material, was to give the advantage to the defense, and consequently everyone recognized that good troops behind such protection could hold off three or four times their number of equally good troops making the assault.
This was the proportion depended on, and the calculations of the commanding generals
were made accordingly.
It was usually considered that troops in the works were inferior to the assailants if they did not succeed in withstanding the attack of several times their own strength.
Naturally, also, the character of the works changed somewhat with increasing experience.
With rifles, an entrenched line was almost certain to be able to dispose effectually of an approaching force which had eight hundred yards over which to advance in the open, or over ground partially open.
In woods, an abatis, or entanglement, was an effectual aid in stopping the advance before it reached the works, since it delayed the line, and enabled the defenders to get a close-range fire on the assailants.
Beginning with the battle at New Hope Church
, on the 25th of May, 1864, almost every advanced line, of either side, entrenched itself as soon as the position was taken up. Whenever an organization was moved, its commander sent out a skirmish line ahead of the new position, for the protection of the men engaged in entrenching; caused an inspection of the ground to be made by competent officers to determine the location of the trenches, and then ordered his men to work.
The workers stacked their arms, took tools from the wagons or availed themselves of those carried by the troops, and each small organization — company or battalion — entrenched its own part of the line.
In timber, huge logs were placed in position and
“Soft” walls better defenses than “hard” --Fort Sumter
In 1863, the stone walls of Sumter were soon breached by the guns of the Federal fleet, but behind the breaches rose many feet of gabions filled with earth.
These were replaced as fast as the guns of the fleet dislodged the soft earth.
General G. T. Beauregard wrote in his official report of February 8, 1863: “The introduction of heavy rifled guns and iron-clad steamers in the attack of masonry forts has greatly changed the condition of the problem applicable to Fort Sumter when it was built, and we must now use the few and imperfect means at our command to increase its defensive features as far as practicable.”
This beautiful view of Fort Sumter in 1865, clear in every detail, one of Barnard's photographic masterpieces, shows the battered parapets of the Fort strengthened again and again by gabions.
The humble baskets not only served this purpose, but kept flying pieces of the more solid construction which they reinforced from maiming the garrison.
One would hardly imagine that the declivity in the center of the mass of gabions had once been a well-chiseled flight of steps.
This kind of fortification deteriorated very rapidly unless constantly repaired.
In Sumter the work of repairing was particularly heavy, following one bombardment after another throughout the four years of the war. It was not until February 17, 1865, after Sherman's great march, that the Fort was evacuated. |
covered with earth.
Without timber, the parapets were often made as much as fifteen feet thick, to stop artillery fire.
A head log, under which the men could fire, was frequently utilized.
When struck by a large projectile, of course a log in that position was liable to be thrown backward and injure a number of men. Various methods were used to prevent its coming back, and one device, to prevent injury to the men in case it did come back, was to place skids under it, perpendicular to the line of the parapet, and extending back across the trench so that it would slide over the heads of the men.
Except for special works, all these lines were constructed by the enlisted men with very little direction from the officers, and foreign officers visiting the troops are quoted as being astonished very often at seeing troops of the line performing what, to them, seemed technical engineering duties which, in their services, would be done by trained officers and men.
The Confederates, on their part, occasionally were able to erect their works beforehand, for, when it was decided to retire, the decision was always arrived at deliberately, and time taken to survey the ground more thoroughly than was possible on the side of the assailants.
These works having been erected with more thoroughness than those in the immediate vicinity of the foe, more elaborate preparations frequently were made to defend the works.
Devices such as chevaux-de-frise
, consisting of logs pierced by sharpened spokes, were sometimes resorted to, and palisades were constructed in the ditches of strong works.
One historian has remarked that no clear conception of the remarkable campaign to Atlanta
can be had unless the difficult character of the country and the formidable nature of these artificial defenses are remembered.
Returning to the armies of the Potomac
and of Northern Virginia
, we find that, at Chancellorsville
lost precious time by stopping, after attaining Lee
's flank, and entrenching, instead of making an immediate attack; and another entrenched line — this time of value — was taken up after Howard
had been driven in by Jackson
's flank march and attack.
, the Army of the Potomac made no concerted effort to entrench, but relied largely on natural obstacles.
But a decided change in the record of events commenced when the final campaign started from the Rapidan
, in 1864.
We already have noted how, in the Western
armies, the art of entrenching had been highly developed.
Not to be outdone by their Western comrades, the great armies operating in Virginia
now got down and systematically “dug dirt.”
Each force hugged the ground with bulldog tenacity.
The end was coming.
Everyone saw that the war must stop, and neither army felt that it was the one that was going to meet defeat.
The great battles of the Wilderness
, and Cold Harbor, on the way to Petersburg
, were but a succession of attacks upon improvised fortresses, defeats for the assaulting troops, flank movements to a new position, new entrenchments, new assaults, new flank movements, and so on continuously.
The stronger Northern army never overcame the weaker Southern legions so long as the latter remained in the trenches.
The preponderance of numbers enabled the Federal
armies to extend ever to the left, reaching out the long left arm to get around the flank of the Confederate
This was the final operation in front of Petersburg
To meet the continuously extending left of the Federals
's lines became dangerously thin, and he had to evacuate his works.
He was not driven out by the foes assaulting the works themselves until his lines became so thin that they were broken by weight of numbers.
Here the principle that already had been demonstrated was again shown to be true--one American in the trench was worth several Americans
outside — for all Americans
are intrinsically equal.
While these stirring events of the East
were occurring, Schofield
at Franklin, Tennessee
, attacked by Hood
, proved again that the increasing faith in hasty field-works was not ill
With only a light line of works, he was able to withstand the onslaughts of one of the best armies of the Confederacy
and withdraw with all his trains and supplies, after inflicting a very large loss on the Southerners and sustaining a comparatively light one himself.
Had the conditions been reversed, Hood
's army would probably have done as well as Schofield
's. They were all Americans
of the same intrinsic quality.
One force was behind breastworks, slight as they were, and the other was the assaulting party.
Again, at Nashville
contended on equal terms behind their respective lines, but when Thomas
became sufficiently strong he was able to drive Hood
out of his works and then defeat him, as he did, on December 16, 1864.
The cost of assaults on entrenchments during all these late campaigns of the war was tremendous.
The losses in Grant
's army from the time he crossed the Rapidan
until he reached the James
— a little over a month — were nearly equal to the strength of the entire Confederate army opposing him at the outset.
Again, at Petersburg
, the attack cost the Union
army, in killed and wounded, a number almost equal to the entire force of the foe actually opposed.
As for the profile, showing the strength of parapet of the works employed, there was no fixed rule, and the troops used arbitrary measures.
Ten to fifteen feet of fairly solid earth generally sufficed to withstand the heaviest cannon, while a thickness of two feet and a low parapet would protect against rifle fire.
If logs or other heavy timber were at hand, the thickness of the parapet could be correspondingly reduced.
It was found that even a slight work, if held by strong rifle fire, always prevailed against the advancing force, unless the latter attacked in overwhelming numbers.
Of the stronger fortifications on each side, those exemplifying the best types were the defenses of Washington, of Richmond
, of Vicksburg
, Port Hudson
, and New Orleans, and the works at Mobile
, Fort Fisher
, Fort Pulaski
Burrows of Grant's soldiers besieging Petersburg
In these bomb-proof quarters of Fort Sedgwick, and many others, the Federals sought protection.
When the artillery fire was not making it “Fort Hell” in fact as well as in name, the bullets of the Confederate sharpshooters were singing over the salient and the breastworks.
A cap on a stick thrust above the breastworks was invariably carried away.
Many a man taking a hasty glance over the parapet to note the effect of his own fire was killed.
Barrels and gabions were used to lengthen the chimneys needed for heating the underground huts.
The distance between the main lines, at Fort Sedgwick, was about fifteen hundred feet, and between the pickets only two hundred. |
Confederate entrenchments as far as the eye could reach
The Confederate fortifications in defense of Petersburg were among the most substantial and strongest erected during the war. These tremendous works were built with a degree of skill that has since made them a wonder to military men. They were undermined and blown up by Union troops at the famous “Crater,” but were never carried in a front attack till the final assault after which Lee withdrew. |
These were all elaborate and designed to sustain sieges and assaults of the heaviest character.
There were also other strong fortifications that fulfilled the requirements of modern warfare absolutely.
The improvements in weapons necessitated changing and, in some instances, entirely abandoning the older conceptions of fortresses, and American ingenuity devised works far better adapted to the powerful weapons of destruction that had been secured and developed by both parties to the conflict.
The habit of making themselves secure at all times became so much second nature that it was not confined to the field of battle.
This fact excited the very great interest of foreign observers.
In the latter part of the war, whenever the troops halted for whatever purpose, if for nothing more than a short rest on the march, they instinctively entrenched themselves.
Even before a fire was built, food prepared, or Camp necessities provided for, they frequently set to work to provide a shelter from the foe, and the rapidity with which a serviceable cover could be erected was always a cause for remark.
These improvised works were abandoned with the same unconcern with which they were erected.
It was entirely a matter of course.
Even by casual inspection and comparison of results, the trade-mark of the American
soldier will be found on many of the devices used by the other armies of the world to-day for hasty protection in the field, from the inclemencies of the weather, the disagreeable features of camp-life, and from the enemy.
In common with the mark left by the individuality of his civilian comrade, the soldier's initiative has so impressed foreign observers that the effect on other nations is evident.
In no profession has the American
type stood out more preeminent than in that of soldiering, and in no feature of the military has that same individuality impressed itself more than in the construction of devices for protection against the winged messengers of death loosed so lavishly by the enemy.