The high-wire entanglement may be built with additional rows of fences and triangular cells to form bands of any desired depth, or it may be made more effective by adding front and rear aprons. Other types of fences may be combined in bands to form obstacles that are more difficult to breach than a single belt. Portable, barbed-wire obstacles may be added as described previously. The construction of bands of various types is desirable because this makes it difficult for the enemy to develop standard methods of passage. It also allows for fitting the obstacles to the situation with the time and materials available. Six different types of effective combination bands are shown in figure 8-35. Other variations can be developed readily.

BASIC CONSIDERATIONS

Barbed-wire obstacles are constructed primarily from issue materials; thus both logistical and con-struction estimates are involved. Table 8-1 gives weights, lengths, and other data required for estimating truck transportation and carrying party requirements. Table 8-2 gives the material and labor requirements for construction of various wire entanglements. Table 8-2 is based on daylight work; for nightwork the man-hours must be increased 50 percent.

REQUIREMENTS FOR A DEFENSIVE POSITION

Table 8-2 gives quantities and weights of material per linear foot of entanglement. When a layout to scale can be developed, the lengths of the various types of entanglements are scaled and the quantities and weights are computed. When a scaled layout cannot be prepared, the rule-of-thumb method may be used for estimating the required lengths of tactical- and protective-wire entanglements. If the length of front is taken as the straight-line distance between limiting points, the rules are as follows:

1. The length of tactical-wire entanglement is 1.25 times the length of the front, times the number of belts, regardless of the size of the unit involved.

2. The length of protective-wire entanglement for a defensive position is five times the length of the front being defended, times the number of belts. Since pro-tective wire encircles each platoon area of a command, the protective-wire entanglement for units is 2.5 times the average platoon frontage, times the number of platoons involved.

3. Supplementary wire in front of the FEBA is used to breakup the line of tactical entanglements. Its length is 1.25 times the unit's frontage, times the number of belts. The length of the supplementary-wire entangle-ment behind the FEBA is approximately equal to 2.5 times the distance from the FEBA to the rearmost reserve unit, times the number of belts. This rule of thumb is adequate for all units.