Obstacles, Attack of

In a well arranged attack by open force the storming party whose objective was to reach and pass over the parapet of a temporary work was preceded by a working party whose objective was to clear a good path through obstacles that might impede the storming party's advance, break its orderliness, and throw it into confusion. Each attacking column, both false and real, had to be be preceded by a working party to deceive the enemy as to the intent of each column. The number of troops detailed for an advanced working party largely depended on the time allowed for the destruction of obstacles, the nature of, and number of the obstacles that had to be overcome. Larger working parties could achieve their objective more quickly than smaller parties, but were also more exposed to enemy fire since the troops would be working closer together were more likely to form accidental groups that would become easy targets for the defenders. Each working party was equipped with a proportional number of axes, shovels, picks, sledgehammers, and crowbars; when necessary a few men also carried bags of powder. Special working parties could also be formed to carry fascines, planks, and hurdles to fill ditches and cover low obstacles, while other working parties could be arranged to carry scaling ladders or other heavier and cumbersome equipment such as hand and wheel barrows required for moving large quantities earth for ramping the ditch or undermining the parapet.

The different types of obstacles could be destroyed by different means. Palisades, stockades, and fraises could be cut open with axes or blown down using powder charges. If time allowed, an abatis could be set on fire and allowed to burn away; if it had to be penetrated quickly the working party would set to it with axes, the troops covering themselves as well as possible among the branches, first cutting away the smaller branches and ties that bound the tree trunks to the ground. Ropes could then be attached and the trunks dragged out of the way. Small pickets had to be cut away with axes or knocked down with sledgehammers; heavily woven hurdles could also be thrown over the pickets to form temporary bridges with the pressure of the troops passage forcing inclined pickets toward the ground. Chains or ropes tying cheval-de-frise together could be hacked apart with axes and the chevaux-de-frise dragged aside to allow troops to pass the obstacle. Planks or strong hurdles could be thrown over the tops of military pits to bridge them or they could be filled with fascines, sap faggots, or half-filled sand-bags. A clear path through crow's feet could be made by using small branches with leaves still attached to sweep them aside. Ditches, both wet and dry, could be filled with fascines, or, if the defenders' fire was not overly dangerous and there was sufficient time, shovels and picks could be used to cut a ramp into the ditch from the glacis.

Given enough time artillery could also be used to begin the work of demolishing wooden obstacles prior to the advance of the working party; but most attacks on temporary fortifications happened too rapidly for the battering effect of solid shot and shell to form effective breaches in the obstacles. In most cases artillery concentrated on silencing the defenders' artillery rather than breaching obstacles. Still, wooden obstacles could be destroyed by the combined effect of solid and explosive shells: shot was used to knock holes through palisades, stockades, and plow a path through small pickets. It could also knock chevaux-de-frise apart and displace the cheval-de-frise enough to allow troops to slip through the obstacle. Shells were used to set wooden obstacles on fire and break them apart by the concussive force of their explosion. When directed toward breaching a parapet solid shot was used to break up and loosen the compact soil forming the parapet while shells were used to displace the soil and flatten the parapet. In most cases the destructive work begun by artillery had to be finished by working parties.

January, 2003