Boobytraps

1. What they did

This is a United States Army field manual that teaches soldiers how boobytraps work, how they are used in combat, and how to detect and remove them. It has six chapters:

• Characteristics of boobytraps: what a boobytrap is (“an explosive charge cunningly contrived to be fired by an unsuspecting person who disturbs an apparently harmless object or performs a presumably safe act”) and how the firing chain works.
• Use of boobytraps: doctrine, planning, the basic principles of placing and concealing them, installation, reporting, recording and marking.
• Boobytrapping equipment: firing devices, explosives and accessories, and munitions.
• Installation: in minefields, in and around buildings, and on roads, trails, paths and other terrain.
• Miscellaneous boobytraps: factory-made devices used by armies in World War II, and devices improvised in guerrilla warfare.
• Detection and removal: clearance teams, tools, detection, outdoor and indoor searching, and disarming.

Most of the manual is technical instruction on explosives and firing devices. This entry focuses on what it teaches about reading signs, awareness and searching ground.

2. What they found

Hiding the signs of the work

• The manual’s first principle is concealment: “All litter and other evidences of boobytraping must be removed.”
• After laying boobytraps, teams are told to leave the area clean, carrying away “loose dirt, empty boxes, tape, and broken vegetation” that might betray the work, and to “obliterate footprints.”
• Boobytrap teams are told to study the personal habits of enemy soldiers, and to keep changing their methods, because repetition “may soon become a pattern easily detected by an alert enemy.”
• Trails, paths, defiles, obstacles, gathering places and objects that appeal to curiosity are described as likely places for boobytraps. An obvious firing device may distract attention from a hidden one.

Detection is careful observation

• “The most careful observation is required for the detection of boobytraps.” Every soldier, whether or not they are assigned to clear boobytraps, must be alert “for any sign that may indicate their presence,” especially in areas the enemy held before.
• Prisoners of war and local people often give useful information. Searching parties are briefed on everything known about enemy activity in the area before they go out.

Signs to be suspicious of outdoors

• Movable and apparently valuable or useful property.
• Disturbed ground, and litter from explosive containers.
• Marks left on purpose to attract or divert attention, and unusual marks that may be an enemy warning of danger.
• Evidence of former camouflage.
• Abrupt changes or breaks in the continuity of any object, such as unnatural appearances of fences, paint, vegetation and dust.
• Things that do not belong, such as nails, wire or cord.
• Obstructions: search before lifting a stone, moving a low-hanging limb or pushing aside an object.
• “Queer imprints or marks on a road, which may lead a curious person to danger.”
• Abandoned vehicles, dugouts, wells, bridges, gullies and defiles.
• Areas where nothing has yet been found, and areas with one obvious trip wire: there may be others.

Searching indoors

One searcher per room; examine both sides of a door before touching it; check furniture, drawers, switches and repaired areas; work from the basement upward; and guard buildings until they are occupied.

Tools and fatigue

Mine detectors can give false signals from scrap metal, air pockets, roots or disturbed soil, and operating time should not exceed 20 minutes because “tired operators often become careless operators.” Searching parties must rest often: “A tired man, or one whose attention is attracted elsewhere, is a danger to himself and others.”

3. What they concluded

• Clearing every charge is “almost impossible,” so careful, disciplined observation and thorough searching are essential. Never assume an area is clear without further investigation.
• “A soldier by training can develop his sense of danger. Also by experience and careful continuous observation of his surroundings while in a combat area, he can develop an acute instinct that warns him of danger.”
• Rules of conduct include constant practice, patience, letting only one person deal with a boobytrap, and being “suspicious of every unusual object.”

4. How tracking was or was not used

The manual does not use the word tracking, but its detection chapter is about reading signs of human activity on the ground: disturbed soil, broken vegetation, imprints and marks on roads, traces of camouflage, and anything out of place or breaking the natural continuity of a scene. From the other side, it tells soldiers laying boobytraps to remove litter, loose dirt and broken vegetation and to wipe out their footprints, so that no signs remain. No trailing is described.

6. Other technologies, skills or innovations

• Metal and nonmetallic mine detectors (AN/PRS-3 “Polly Smith”, a transistorized model, and AN/PRS-4).
• Probes (metal rods, stiff wire or bayonets), with sleeves rolled up to feel for trip wires.
• Grapnels and long ropes to pull objects from a safe distance.
• A hand mirror and flashlight for looking into cavities; a light and line of sight for checking flues and shafts.
• In World War II, a hidden delayed charge and its clockwork fuze in a building were found with a stethoscope.