What the Viet Cong (VC) and the North Vietnamese Army (NVA) lacked in the way of firepower they made up for in ingenuity. Concealed devices used to inflict casualties, booby traps were an integral component of the war waged by Viet Cong and People's Army of Vietnam (PAVN) forces in Vietnam. These devices were used to delay and disrupt the mobility of U.S. forces, in fact, the threat was often enough to slow any advance to a snail's pace, divert resources toward guard duty and clearance operations, inflict casualties, and damage equipment. They were a key component in prearranged killing zones. Booby-traps could be covered by snipers to further annoy the enemy or they might be the signal to spring an ambush.
The use of booby traps also had a long-lasting psychological impact on Marines and soldiers and helped to further alienate them from civilian populations that could not be distinguished from combatants. The fear of booby-traps and mines was so great that units in the field (the boondocks) and the jungle (the zoo) were under stress the whole time. This created severe mental fatigue on both the commanders at platoon level and the individual soldiers.
Many of the materials for the mines and booby traps were of U.S. origin. These included dud bombs, discarded and abandoned ammunition and munitions, and indigenous resources such as bamboo, mud, coconuts, and venomous snakes.
The imaginative use of booby-traps by the NVA and VC caused many casualties amongst their opponents. Between January 1965 and June 1970, 11% of the fatalities and 17% of the wounds among U.S. Army troops were caused by booby traps and mines. To give one historical example, Charlie Company of the First Battalion, 20th Infantry sustained over 40% casualties in 32 days. They scarcely saw the enemy and took the casualties mainly from booby-traps and snipers. The effect on morale was such that these losses in men and the fact that they included virtually all of the experienced NCO's was said to have been more than partly responsible for the My Lai massacre that occurred.
Booby traps can be divided into explosive and non-explosive antipersonnel devices and anti-vehicle (i.e., tank, vehicle, helicopter, and riverine craft) devices. Antipersonnel booby traps were concentrated in helicopter landing zones, narrow passages, paddy dikes, tree and fence lines, trail junctions, and other commonly traveled routes. Anti-vehicle booby traps were deployed primarily on road networks, bridges, potential laager positions, and riverine choke points.
Non-explosive antipersonnel devices included punji stakes, bear traps, crossbow traps, spiked mud balls, double-spike caltrops, and scorpion-filled boxes.
By far the most common types of booby trap was the single punji stake. Punji stakes were sharpened lengths of bamboo or metal with needle-like tips that had been fire-hardened. Often they were coated with excrement to cause infection. Dug into shallow camouflaged holes and rice paddies and mounted on bent saplings, this was a common booby trap. Another similar device was a spiked mud ball suspended by vines in the jungle canopy with a trip-wire release. It functioned as a pendulum, impaling its intended victim.
The simplest pit type was a hole about 20 to 30cm deep. The floor of this trap was then set with punji stakes which could easily pierce the canvas and leather jungle boot. For added misery the spikes could be smeared with poison or human excrement to induce blood poisoning or worse. There were many variations which allowed the spikes to attack the sides of the leg. This was particularly favored after the introduction of the reinforced soled jungle boot.
Punji traps were laid wherever the enemy soldiers were likely to land with force. The purpose of the pit was to increase the downward force of a walking man. Such places included the places that soldiers would throw themselves to escape gunfire - ditches, behind logs, in long grass etc; or where they would land with some force - stream banks, likely helicopter landing zones etc.
Side closing traps were also to be found. These ranged from the same size as the punji pit up to man-sized traps. These were more sophisticated versions of the punji pit and were likewise smeared with excrement or poison.
The second group of non-explosive traps used some form of mechanism to set them off - usually a trip wire. The wire could be stretched across a track as a delaying tactic or linked to a hidden man to be released on command as part of an ambush or to hit a selected target.
The swinging man trap was positioned on jungle trails and heavily camouflaged. It comprised a weighted beam pivoted so that when the pressure plate was pushed down the other, spiked end swung upwards with enough force to impale the victim. The target area was the chest in order to inflict a messy fatal wound.
The bamboo whip was encountered on trails and was set off by a tripwire. It comprised a length of bamboo under tension and set with spikes (poisoned in the normal fashion) at chest height. The unfortunate victim would receive severe, it not fatal, wounds to the chest as it whipped across the trail
The spiked ball was another trap designed for jungle use. It was sprung by a trip wire which released the heavy clay ball set with sharp spikes. The force of gravity and the height of release combined to inflict horrific, usually fatal, wounds in the head and shoulders region.
The bow trap was a favorite in the heavily forested mountainous areas - though it was not limited to these. It too was tripped by a wire which released a tensioned bow set in a shallow pit. The target area was the leg. The arrow was normally tipped with poison or human excrement.
Variations of explosive antipersonnel devices encompassed the powder-filled coconut, mud ball mine, grenade-in-tin-can mine, bounding fragmentation mine, cartridge trap, and bicycle booby trap. The mud ball mine was a clay-encrusted grenade with the safety pin removed. Stepping on the mud ball released the safety lever, resulting in the detonation of the mine. The cartridge trap was a rifle round buried straight up and resting on a nail or firing pin. Downward pressure applied to the cartridge fired it into the foot of the intended victim.
These were normally set to give warning of an approaching force or as part of an ambush. They were also employed to slow down a follow-up force after an ambush or to cover a withdrawal. The generally poor quality of the grenades used by the VC and NVA combined with their (relatively) long fuse of 5-6 seconds made them much less effective than they might otherwise have been. If circumstances permitted captured US fragmentation grenades gave a much better performance.
The simplest trap was a trip wire connected to one or two grenades. The grenades were placed in tubes of bamboo or tins to keep the safety lever from releasing when the pin was pulled. The victim tripped the wire, set at whatever height, pulling the grenades from their containers.
Command-detonated grenade '~daisy chains" were set along trails where patrols were likely. These grenades were set close together to inflict casualties at a point where there would be a bunched target. Bunched targets could occur naturally at certain terrain features or be created by using other traps to create casualties and then hitting the evacuation teams. The number of grenades chained together would be dependant on the strength of the puller and the length of the wire.
Grenades were also set in the ground below gates so that the slightest movement of the gate would detonate it right below the victims' feet. In areas where the vegetation closed above the trail grenades were often set to shower splinters of wood and metal downwards, causing messy wounds which would require urgent casualty evacuation.
Claymores were an especially lethal form of mine with both the US and Chinese versions hurling fragments in a 60 degree fan. The locations that were usually mined were roads, edges of roads, enemy escape routes from ambush sites, crossing places, village approaches, behind fallen logs, behind walls, gaps of any type and so on.
Dud shells and bombs were salvaged and turned into traps, mines or sources of explosives. The shell most commonly available for this was the 105mm artillery shell.
A small variation of this used a 12.7 mm machine gun bullet set in a bamboo tube with its primer resting on a nail or firing pin. The tip of the bullet just protruded from the earth. A foot would press down sufficiently to set it off. The bullet would explode shattering the victim's foot. If he was unfortunate enough to be wearing the reinforced soled jungle boot then the steel or plastic plate turned into shrapnel. The grunts called these 'toe poppers". They were usually set in long grass.
Traditional anti-personnel mines of all sorts from WW2 vintage onwards were used as they were intended and as part of booby-traps. One of the most common, and most hated, was the "Bouncing Betty". These mines were triggered by the release of pressure on the arming mechanism. Thus a soldier could stand on one, hear the arming mechanism operate and freeze. There he was standing erect knowing that if he moved his foot the mine would jump into the air and explode at chest height. Combat engineers came up with many extemporized methods of saving trapped soldiers.
The VC and NVA did not booby trap "souvenirs" to the same extent that the Japanese and Germans did in WW2. They did do it, but it was uncommon and possibly the more effective for that.
ANTI-VEHICLE TRAPS & MINES
Anti-vehicle devices included the B-40 antitank booby trap, concrete fragmentation mine, mortar shell mine, and oil-drum charge. The B-40 was a rocket-propelled antitank grenade, which in this instance was placed in a length of bamboo at the shoulder of a road and command-fired at a vehicle crossing its forward arc. The mortar mine was simply the warhead of a large-caliber mortar that had been separated from its body and retrofitted with an electric blasting cap. The oil-drum charge was based on a standard U.S. 5-gallon oil drum filled with explosives and triggered by a wristwatch firing device. This booby trap had immense sabotage applications for use against fuel dumps.
Soft vehicles could be destroyed by several of the anti-personnel mines or booby-traps described above. The VC and NVA used large numbers of mines to destroy enemy AFV's and were so proficient that the drivers and crews of the lighter sorts of AFV's rode on the outside of the vehicles. The crews of all vehicles would attempt to reduce the effectiveness of mine blast by putting layers of sandbags on the floor. This naturally affected the mobility of these vehicles. Some M-113's and M-551's were overloaded by doing this.
Captured artillery ammunition was prized for destroying tanks. The shell would be set in a culvert or similar location and command detonated under the track of the target. This was highly effective, particularly against the M-41's and M-551's. It was also very difficult to do correctly.
The habitual riding on the top of AFV's exposed the crews to sniper fire or to the anti-personnel traps set high enough to catch them. The threat must indeed have been real enough for the crews to accept the loss of their armour protection.
As the war progressed the prediction of likely helicopter landing zones became an art at which the VC and NVA became adept. The edges could be trapped or mined, the LZ's could also be mined or registered as mortar and heavy machine gun targets. However, a booby trap for helicopters consisted of wires connected to grenades atop posts at the edge of the LZ at a height to inflict blast and splinter damage on the debussing troops and splinter damage on the helicopters themselves, with the rotors being particularly vulnerable. Another particularly nasty anti-helicopter trap was the claymore mine sited on it's 'back' to fire up into the air as the helicopters were on final flare, sending hundreds of steel pellets through the soft belly of the helicopter. Still other mines were rigged into the tops of trees to be detonated by the rotor wash of nearby helicopters.
These devices were used on a scale never before encountered by U.S. military forces. As the war progressed and the casualty list stemming from booby traps mounted, U.S. forces employed numerous countermeasures. The most effective countermeasures were proactive in nature and focused on the destruction of underground VC/PAVN mine and booby trap factories and the elimination of raw materials used in the manufacture of such devices.
Tactical countermeasures included using electronic listening devices and ground surveillance radar; patrolling; deploying scout-sniper teams and Kit Carson Scouts; booby trapping trash left by a unit; and employing artillery ambush zones. Principal individual countermeasures were wearing body armor, sandbagging the floors of armored personnel carriers (APC's), and abstaining from the collection of "souvenirs".
See Also:Official US Army Report prepared by Captain James M. Cox, 1st Battalion, 52nd Infantry
Doleman, Edgar D. Tools of War. The Vietnam Experience. Boston: Boston Publishing, 1984.
U.S. Army Foreign Service and Technology Center, Mines and Booby Traps, (Translation of Minas E Armadilhas.) Washington, DC: Department of the Army, 1969.
U.S. Marine Corps Base, Quantico, Vietcong Mine Warfare, Quantico, VA: Department of the Navy, 1966.
Wells, Robert, ed., The Invisible Enemy: Booby-traps in Vietnam, Miami, FL: J. Flores Publications, 1992.
Alan AD Hamilton, The Boondocks and the Zoo, Wargames Illustrated n. 22, June 1989