Use wire entanglements in the outer protection areas of howitzer positions. Similarly, protect heavier weapons, reserve area shelters, and other installations in the reserve area if justified by the situation.

Antipersonnel Obstacles

Site barbed-wire entanglements, trip flares, noisemakers, and antipersonnel mines to detect enemy patrol action or infiltration at night; to prevent the enemy from delivering a surprise attack from positions close to the defenders; and to hold, fix, or delay the enemy in the most effective killing ground. Site such obstacles near enough to defensive positions for adequate surveillance by the defenders by night and day and far enough away to prevent the enemy from using hand grenades against the defender from points just beyond the obstacles.

Roadblocks

Figure 8-3 shows a series of barbed wire concertinas that will stop wheeled vehicles. Use a series of these blocks placed about 33 feet apart. Wire together the ends of adjacent coils and lightly anchor the obstacle at the sides of the road. Site the block to achieve surprise.

Strengthening Natural Obstacles

Deep rivers, canals, swamps, and cliffs are effective delaying obstacles to infantry. Thick hedgerows, fences, and woods can slow troops to a lesser degree. You can improve both of them by lacing the obstacles with barbed wire, by the addition of parts of standard fences on one or both sides, or by entangling with loose wire.