Fortification Friday: Crows-foot, Small Pickets and Entanglements could put you on the disabled list

A fine point about the functional nature of obstacles – determent value is measured in both the ability to impede and injure.  You might call it a philosophical nuance, in context of the military art, but the distinction is important when considering the application of obstacle types.  In practical terms, recall how the abattis and palisade were employed. These were designed, first and foremost, to slow the attackers’ forward progress, if not bar such entirely, by standing on the line of advance.  Granted, if the obstruction were oriented properly and the attacker approaches with a high rate of speed, there could be injuries.  An abattis is all fun and games until someone looses and eye!  But even with a chevaux-de-frise, with the specified iron points, an attacker would need to do something really… well… awkward to induce a blood-letting injury.  Their chief value lay in slowing or stopping the attacker just by being in the way.

On the other hand, there were obstacles that by nature were designed to draw blood.  One of those was the crows-foot.  Mahan described this obstacle as such:

The crows-foot is formed of four points of iron, each spike about two-and-a-half inches long, and so arranged, that when thrown on the ground one of the points will be upwards.  They are a good obstacle against cavalry, but are seldom used.

Crows-foot are called caltrop among audiences which prefer Latin.  Being an American, I eschew those fancy European terms where possible. Crows-foot sounds more “country.”  Any rate, here’s what we are referring to:


Despite Mahan’s lack of enthusiasm for the crows-foot, the obstacle type remains in use today.  The term is used to describe large concrete and steel obstacles designed to deter armored vehicles.  Or on the beach to stop landing craft.  To some degree it is an “offensive” obstacle… and in both senses of the word.  And for emphasis here, the crows-foot doesn’t actually block movement, it injures so as to debilitate – be that a horse, a man, or, in the modern sense, a vehicle.

The downside to crows-feet was the nature of emplacement.  Being sown, or basically scattered, and not pinned down, the crows-feet were not easily delineated for the defender’s convenience.  An alternative was a simple field expedient:

Boards, with sharp nails driven through them, may supply the place of crows-feet.  The boards are imbedded in the ground, with the sharp points projecting a little above it.

This, readers, is why soldiers need tetanus shots.  Embedded in the ground, the boards could be arranged in a pattern, identified for the defender, but with the nails concealed in the dirt or surface debris.  Junius Wheeler added another alternative in his post-war manual, mentioning the farmer’s harrow.


Buried upside down, the spikes of the harrow would likewise injure an unwary foot.

We don’t see many references to crows-foot or similar obstructions in the Civil War.  Not to say these were not used, but rather their use was not deliberately noted.  On the other hand, we see many references to small pickets with added entanglements.  We should start by explaining small pickets:

Small Pickets. This obstacle consists of straight branches of tough wood cut into lengths of two-and-a-half, or three feet.  They are driven into the ground, in quincunx order, about twelve inches apart, and project irregularly above it, not more than eighteen inches.

We have Figure 26 from Mahan’s manual to illustrate where the small picket might be used in the ditch:


Better yet, let us turn to Wheeler’s illustration:


The key point to latch on to here is the arrangement.  Unlike the stakes in military pits, these are arranged in close order with the aim to force the attacker to think about where his foot is placed, lest the small picket pierce the foot.  One might say the intent of the small picket was to discourage.  But the threat behind that discouragement was that of a skewered foot.   In function, the small picket was much like the punji stake from the Vietnam War:


So again we see the obstacle could be “offensive” in application.  But in the Civil War context, booby-traps of this nature were not widely used.  The need was for an obstacle that would stop a massed attack, not a trail patrol.  So we read in many accounts of an enhancement to the small pickets:

Interlaced with cords, grape-vines, brambles, prickly shrubs, &c., they form an excellent entanglement.

And in the 1860s, engineers would add one readily available material to that list – wire. Wheeler described the arrangement as, “… made by driving stout stakes into the ground from six to eight feet apart and connecting them by stout wire twisted around the stakes.”  This was an easy obstacle to set up, with materials easily obtained.


Fine point of observation here – Mahan’s entanglements were offered as a means to enhance the small pickets.  Basically, the intent was to trip the attacker onto the small pickets.  In Wheeler’s entanglements, which reflected wartime experience, the tripping on the wire itself was sufficient deterrent.  Thus the pickets could be spread out more. An excellent description of such comes from Major Thomas Brooks in his extensive journal of operations on Morris Island in 1863:

This obstacle was made by setting stout stakes, 3½ feet long, 2 feet in the ground and 7 feet apart, in quincunx order, and in three lines.  Around the top of these stakes, from 12 to 18 inches from the ground, in notches prepared to receive it, No. 12 wire was securely and tightly wound, and extended from one to the other.

Brooks reported laying 300 yards of wire entanglement on Morris Island, requiring 13 coils of wire (length unspecified) and an additional 890 feet of loose wire.

The function of Brooks’ entanglement obstacle was to deter by the threat of injury – lest the attacker be bruised and banged up from tripping.  Perhaps a little nicer than Mahan’s little impaling stakes.  But still an obstacle designed to injure.  And of course, with the perspective of history, we recognize Brooks wire entanglement as an evolutionary step towards barbed wire of World War I and later concertina wire. In those forms, we see the obstacle designed not just to trip and bruise but to draw blood.  Either way around, bruised, banged, cut, or impaled, the soldier was thus a casualty… and if lucky just placed on the disabled list.

(Citations from Dennis Hart Mahan, A Treatise on Field Fortifications, New York: John Wiley, 1852, page 48;  Junius B. Wheeler, The Elements of Field Fortifications, New York: D. Van Nostrand, 1882, page 173; OR, Series I, Volume 28, Part I, Serial 46, page 304.)

“Necessitated from the untenable condition of Battery Wagner,” Confederates evacuate

In the early morning hours of September 7, 1863, a deserter stumbled into the Federal siege lines.  Immediately captured, the deserter offered welcome news –  The Confederates abandoned Morris Island during the night. Instead of one final assault on the works, the Federals could simply walk into the fortifications.  The siege of Battery Wagner was over.

Major Thomas Brooks summarized the last few days of the siege in his journal of operations:

In this bombardment, which lasted forty-two hours, four distinct lines of batteries were used, each firing over those in advance of it. Mortars were fired from the fifth, third, and first parallels, and heavy rifled guns from the second parallel and left batteries. The practicability of this method of using guns, into which we were forced by our narrow front, was demonstrated.

Brooks also provided a complete assessment of Battery Wagner, as only an experienced military engineer might, recording the damage at the time of capture. As one might expect, he found substantial damage.  But in regards to the bombproof shelter inside the sea-facing bastion, he observed:

Considerable earth, which covered the south end of the main bomb-proof shelter, and the magazine just east of it, was removed by our fire. About 7 feet was left, however, which was enough to make both structures secure against a much longer continued fire.

I’ve seen this part of Brooks’ report used as evidence the Confederates abandoned Battery Wagner for other reasons.  Matching this with diary entries from Captain (later Lieutenant Colonel) H.D.D. Twiggs who served as a staff officer at times during the siege, some have claimed it was the lack of potable water which triggered the withdrawal.  As if the Confederates might have held out a week, perhaps, since the Federal efforts had not rendered the fort itself untenable. (One example where this notion about bad water surfaces is in a Wikipedia article citing an article from North & South magazine.  See reference 2.)

Nothing could be further from the truth. With respect to the water, I would further point out that the Confederates were in the habit of sending a water boat on the routine runs to Morris Island.  And placing Brooks’ statements in context, the assessment was to the structural integrity of the bombproof, not the overall status of the works.

On more than one forum I’ve seen Colonel Lawrence Keitt’s dispatch (sent at 3:15 p.m. on September 6) stating “And if our sacrifice be of benefit, I am ready.  Let it be said so, and I will storm the enemy’s works at once, or lose every man here.”  That was a statement of bravado, aimed more at his superiors than an assessment of reality.  What is often left out from the citation is the preceding questions in Keitt’s message: “Will boats be here to-night for garrison? If so, at what time?”   Leave no doubt, Keitt wanted to evacuate the island, but he had to be careful how that idea was floated.

Within an hour of Keitt’s inquiry, orders came to evacuate the island.  In his final report as commander of the Morris Island garrison, Keitt related the state of the defenses prior to evacuation:

[The evacuation] was authorized by a dispatch sent by signals from district headquarters, and received by me between 4 and 5 p.m., and directed in detail by a special order from department headquarters, which was received from Captain [W. G.] McCabe, of General [Roswell] Ripley’s staff, at dark, and was necessitated from the untenable condition of Battery Wagner, the greatly exhausted condition of the garrison, and constant artillery and sharpshooting fire of the enemy, which prevented repairs. The gradual approaches of the enemy had passed the front of the battery, and the termination of their sap was not over 50 yards from the parapet of the sea face, enabling them to throw a mass of troops upon this flank when our men were mostly in the bomb-proofs, where I was forced to keep them by the unceasing fire of mortars and rifled guns on land, with an enfilading fire from the fleet during most of the day. The salient on the left of the battery had been swept by such a terrible cross-fire as to breach the parapet and throw it into irregular shapes, rendering the ascent from the moat easy, and moreover, men could not be kept there during this cross-fire without the certainty of most of them being wounded or stunned. This salient is the part of the work gained by the enemy in the assault of July 18.

No doubt about it, the damage done to the battery and the proximity of the Federal lines prompted the evacuation.  Bad water and other situational factors made further defense of Batteries Wagner and Gregg difficult.  But it was those fellows in blue uniforms which forced the evacuation.

I think it significant that Keitt mentioned the July 18th assault in his report.  He was alluding to a particular portion of the battery which was the most exposed to assault.  And that salient had been the target of Federal efforts starting with the July 11th assault.  Yet Keitt’s memory focused on the later assault.  Some of the men who had reached that salient on July 18 were advancing the siege lines forward on September 6.  The 54th Massachusetts, as you may recall, was on fatigue detail in those final days.

(Citations from OR Series I, Volume 28, Part I, Serial 46, pages 302 and 483.)

150 Years Ago: The siege lines reach Battery Wagner

Starting his journal entry for September 6, 1863, Major Thomas Brooks wrote:

The sap is progressing to-day. One branch is to pass to the left and the other to the right of the bastion of the fort, thus enveloping it.

To-day, as yesterday, men are constantly exposing themselves above the parapets without drawing any fire from the enemy. Indeed, in the extreme front, there is no danger excepting from our own fire. Fragments of our own shell fly back to our trench, in one case inflicting a severe wound. The fort is as silent as a natural sand bank, which, indeed, it much resembles. All the outside revetments of the work, its lines and surfaces, are destroyed by our fire. It looms over the head of the sap, a huge, shapeless sand bluff.

At last, the trench lines traversed the final yards to Battery Wagner.  On the map, those last few trench lines enveloped the sea-side bastion of the battery.


As Brooks described, the left branch of the trenches reached out towards the land face of the bastion.  The other branch ran along the beach.  A photo staged after the siege depicts the final advances of the sap through these last few yards:


And that is Battery Wagner’s bastion in the distance to the right.

To cover the advance trenches the engineers laid out a Billinghurst-Requa position in the boyaux dug the previous day along the beach.  This would be the last of the numerous positions built for those proto-machine guns during the siege.  Another improvement was to widen the forward trenches to allow massing of troops for the planned assault on the battery.

The USS New Ironsides continued to fire on Battery Wagner despite the proximity of the lines.  To give the Navy a marker, the engineers placed a U.S. flag at the head of the sap.  Brooks  offered an up-close description of the fire effects on the fort:

Standing between the fires, and within a few yards of the point of striking, the opportunity to observe the effect, in the sand, of these huge shells from the smooth-bore guns of the navy and the rifles of the army was perfect. The ricochet of the former was uniform, and landed nearly every one in the fort. That of the latter was irregular; most of them exploded when they struck, throwing up a great quantity of sand, which falls back in its place; hence inflicting no injury save what may come from the heavy jar.

Although the trenches had moved past most of the torpedoes, at least one remained to cause harm.  Lieutenant Patrick McGuire reported one engineer killed and three infantry wounded by a torpedo explosion.

As the Federals reached the ditch in front of Battery Wagner, they encountered a new obstacle.  Captain Joseph Walker reported the presence of stakes and boarding-pikes.  The later requisitioned from Charleston’s supply of antiquated weapons at the start of the siege. He cleared a few hundred of these out of the counterscarp of the ditch.  By 10 p.m. Walker was in the ditch, taking observations to aid the storming party scheduled for the early morning hours of September 7.

But, before we get too far ahead, there was a plot twist to this last act in the long play on Morris Island.

Photo credit: Hagley Museum and Library collection of Haas & Peale photographs, ID Number 71MSS918_039.tif.

(Citation from OR Series I, Volume 28, Part I, Serial 46, pages 300-302.)