Fortification Friday: Talking about the Palisades… but not the park!

There, you have Freddie Cannon in your head.

But we need to segue from that “Cannon” over to discuss one of the obstructions that engineers would put in front of cannons placed in Civil War forts – palisades.  In his pre-war text on field fortifications, Mahan described palisades as such:

Palisades. A palisade is a stake about ten feet long, and of a triangular form, each side of the triangle being eight inches.  The trunks of straight trees should be selected for palisades.  The diameter of the trunk should be from sixteen to twenty inches.  The trunk is sawed into lengths of ten-and-a-half feet, and is split up into rails, each length furnishing from five to seven rails. The palisade is pointed at top, the other extremity may be charred if the wood is seasoned; otherwise the charring will be of no service…

Mahan referenced his Figure 24 to illustrate palisades.  We’ll circle back to that later.  For now let us go forward to an illustration from the post-war edition of Mahan’s text:

MahanFig60

This being a panel of the Palisading.  But we see five palisades here, about ten (or is that 11 feet?) long, and pointed on the business end.  Mahan continued to explain how to place these palisades:

A palisading is a row of palisades set in the ground, either vertically, or slightly inclined towards the enemy. To plant the palisades, a trench is dug three feet deep; they are then placed about three inches asunder, with an edge toward the enemy. Each palisade is nailed to a strip of thick plank, termed a riband, placed horizontally about one foot below the ground; another riband is placed eighteen inches below the top; the earth is firmly packed in the trench.

We see the ribands on the figure above, as they connect individual palisades to form the panel. Though, the placement of the top riband is somewhat different in the figure.  Instead of being eighteen inches above the top, it is about two-thirds the way down. The reason for the figure’s variation will be explained below.  Figure 59 (again, from the post-war edition) illustrates the placement of a panel inclined “towards the enemy”:

MahanFig59

Writing even later after the war, Junius B. Wheeler offered a simplified definition of palisades:

A palisading is simply a fence, made of strong and stout poles or pickets firmly set into the ground.

I’d offer that modern readers can best relate to Wheeler’s short, simple definition… and will glean more from his supporting illustration:

WheelerFig69

We see the triangular form of the posts. We also see the placement of the top riband is approximately that specified in the text.

Setting those details of construction aside, let us turn to where the palisade best integrated with the other features of the defense.  One important point to this is the palisades, like the abattis, should not interrupt the defender’s field of fire or provide the enemy a purchase in front of the line:

As an obstacle, it is best placed at the foot of the counterscarp; the points being twelve inches below its crest, or else covered by a small glacis. In this position the palisading fulfills all the conditions of an efficient obstacle; it is under the fire of the work; covered from the enemy’s fire; will not afford a shelter to the enemy; and cannot be cut down without great difficulty.

And we see that in Figure 23 (of the pre-war textbook):

PlateIIIFig23A

Looking closely:

PlateIIIFig23B

Just as suggested, the palisade is at the foot of the counterscarp. Note the top riband’s location matches, approximately, that of the text.  Notice how the top of the palisade remains below the line between the crests of the scarp and counterscarp. Likewise, the positioning ensures an attacker gaining the counterscarp would end up in a fix and unable to advance without first breaking up the palisade.  If the trace of the works is well designed, the counterscarp would be under fire from adjacent faces or flanks.  It would be a bad place for a pause.

Mahan also offered an alternative application of palisading:

A palisading is sometimes used as a primary means of defense, particularly for low works. A banquiette is thrown up for this purpose against it; the tread of the banquette being six feet below the top of the palisading, and four feet three inches below the upper riband.

Neither Mahan or Wheeler offered an illustration of such. But it is not hard to imagine.  The specification of the height of the banquette is an important detail.  The specification ensured the earth piled up provided just the right parapet for the defender.

We see read of palisading used throughout the Civil War.  What’s more we see palisadings in many wartime photos.  With that sort of documentation, we have an interesting view of how that obstacle’s use evolved during the war.  One of those evolutions was documented by Mahan himself after the war:

An inclined palisading (Fig. 59) is sometimes placed in an advanced position in front of an ordinary trench to secure it from surprise.  This was done to secure a line of trench at the siege of Fort Wagner.  The palisading was made at the depot in panels (Fig. 60) of four or five palisades, cut from pine saplings varying from four to eight inches in diameter, those above five inches being split in two, and placed with the bark side upwards. The spaces between the palisades were left only small enough to prevent a man from forcing his body through them.

So we see why the ribands in Figure 60 were at odds with that of Mahan’s text. These were “Confederate” palisades, more specifically the Charleston depot’s palisades.  We don’t get a photo of the Confederate works. But if you recall the photos taken of Battery Wagner/Fort Strong at the end of the war, there are palisades placed by the Federals to protect the ditch:

Wagner1C

What I like about this view, is the angles thus demonstrated.  In the distant center we see a cannon in place to sweep the front.  The palisades do not interfere with its fire.  That weapon covered the face on the opposite side of the fort (the parapet on top of which the photographer was standing).  Likewise, weapons on the photographer’s flank position were covering the front of the flank in front of the cannon.  Any attacker trying to clear the ditch would be stuck under the palisade and subject to proverbial withering fires.  Note also what appears to be a riband on the palisades in front of the cannon.  Those appear to be constructed according to Mahan’s instructions.  Those in the foreground do not appear to have a riband above ground… and are in need of maintenance.  Just saying.

And other wartime photos offer glimpses of further evolution…and the complexity of the works that were used.  Consider this image from the Atlanta defenses:

03415r

Three types of obstacles (and a couple types of revetments) in view.  We’ll get to the chevaux-de-frise in time.  What’s impressive is the use of several belts of palisades directly in front of the defended line. Belts of inclined palisades supplement a vertical line near the works.  Note the very narrow gap between individual palisades.  Hardly any way to get through them without completely dismantling a section.  And the vertical palisades are above the line of the parapet.  Well above in some places. I submit this is another evolution in the use of palisades (and fortifications in general).  As this is already a lengthy post, let me save detailed discussion of this (and other Altanta photos) for a future post.

(Citations from Dennis Hart Mahan, A Treatise on Field Fortifications, New York: John Wiley, 1852, pages 45-6; Mahan, An Elementary Course of Military Engineering: Part 1: Field Fortifications, Military Mining, and Siege Operations, New York: John Wiley & Son, 1870, pages 74-5; Junius B. Wheeler, The Elements of Field Fortifications, New York: D. Van Nostrand, 1882, pages 174-5.)

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