Last week, we noted the subtle, but expanded, changes applied post-war to instructions offered to cadets studying the construction of traverses in field fortifications. In that installment we focused on the heavy variety which would protect against shot and shell arriving on the works from slant or enfilading fires. A lesser type of traverse, which to be fair was mentioned in Mahan’s pre-war manual also, was a splinter-proof traverse to protect against fragments and, to a lesser extent, shrapnel.
Junius B. Wheeler, writing in the 1880s, retained the label, but offered more details of these lighter traverses:
Splinter-proof traverses. – A traverse intended to be used only as a protection against splinters and fragments of shells scattered around by their explosion, is known as a splinter-proof traverse.
Traverses of this kind are not made so thick, nor so high, as the traverses just described. Their usual height is the same as that of the parapet. Their thickness at the base is from seven to eight feet. Their length varies, being in some cases only ten feet, and in others as much as sixteen feet.
Succinct description. Notice that Wheeler’s definition allowed the engineer to adjust the size relative to the parapet… or shall we say need.
Wheeler continued with a discussion about placement of these light traverses:
As a rule, a traverse of this kind is not joined to the parapet, but is separated from it by a narrow passage, which can be used by the men to pass from one side of the traverse to the other.
Thus, these were often to be detached from the trace of the work.
As for construction, Wheeler provided far more details than Mahan:
A rectangular space is marked upon the ground for the base of the traverse. A row of gabions is then placed in juxtaposition along the line representing the base of the traverse, and given a slope inwards, either by setting the gabions on a slightly inclined excavation in the ground, or by raising the outer edges by means of fascines laid along the ground.
Gabions are then filled with earth, and also the interior space enclosed by them.
When the earth has risen above the top of the gabions, two rows of fascines are laid upon the top of the gabions to form a base for a second row of gabions. This second row is then filled with earth, and the process of filling with earth goes on, until the earth rises high enough. The top is rounded off, or made ridge-shaped, and the traverse is completed.
Wheeler offered this illustration for a splinter-proof traverse:
Not far off that offered by Mahan in the pre-war days.
Closing the discussion of splinter-proof traverses, Wheeler offered some alternative employments and additional notes:
The same method may be used for the construction of traverses required for defilade, when there is a pressing emergency for them.
Splinter-proof traverses are placed between the guns along the line of parapet which is exposed only to a direct fire from the enemy, and are only intended to confine the effects of bursting projectiles to a limited space.
They are usually constructed only when there is a necessity for them, and then hastily. Gabions, sand bags, fascines, or any sort of materials used for revetments, may be employed in their construction.
I get the impression that Wheeler would have approved of modern variations on this theme….
I know.. more a wall than a traverse. But the rapid construction techniques apply equally to placement of traverses inside the wall. Another innovation of late involves the use of what’s called “concrete cloth” to further improve performance. Though of the latter I am somewhat skeptical. Concrete tends to produce nasty little fragments, which can be just as deadly as the shell fragments. Regardless, point being that the practice of fortification continues to evolve but remains grounded in the days of Wheeler, Mahan, and, of course, Vauban.
(Citations from Junius B. Wheeler, The Elements of Field Fortifications, New York: D. Van Nostrand, 1882, pages 130-32.)