TEXT: GORDON L ROTTMAN
  ILLUSTRATED BY BRIAN DELF
  TUNNEL RAT IN
  VIETNAM
  © Osprey Publishing • www.ospreypublishing.com
  
  WARRIOR • 161
  TUNNEL RAT IN 
  VIETNAM
  GORDON L ROTTMAN
  ILLUSTRATED BY BRIAN DELF
  Series editor Marcus Cowper
  © Osprey Publishing • www.ospreypublishing.com
  
  CONTENTS
  INTRODUCTION
  4
  CHRONOLOGY
  6
  RECRUITMENT
  8
  TRAINING
  10
  Basic Combat Training 
  Infantry Advanced Individual Training 
  Combat engineer Advanced Individual Training
  APPEARANCE
  18
  Into the ground
  EQUIPMENT AND WEAPONS
  22
  Tunnel rat weapons 
  Tunnel rat equipment
  CONDITIONS OF SERVICE
  31
  Life in a firebase 
  Chowing down
  BELIEF AND BELONGING
  34
  Into the black echo
  ON CAMPAIGN
  39
  Tunnel rat “units” 
  Combat engineer battalions 
  Chemical detachments
  EXPERIENCE IN BATTLE
  41
  A “cherry” tunnel rat 
  A “routine” day 
  A city underground
  AFTERMATH OF BATTLE
  60
  BIBLIOGRAPHY
  63
  INDEX
  64
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  INTRODUCTION
  In 1965, soon after US combat troops had arrived in Vietnam, it was realized
  that in some areas the Viet Cong (VC) had developed vast tunnel complexes
  in which to hide from the enemy (see Fortress 48: Viet Cong & NVA
  Tunnels/Fortifications of the Vietnam War, Osprey: Oxford 2006). This was
  nothing new. It had long been known that such complexes existed, but it was
  not understood just how extensive they were, their importance to the VC,
  and how difficult it was to detect and neutralize them.
  Most complexes were not nearly as developed and extensive as the
  infamous tunnels of Cu Chi, 25 miles northwest of Saigon, but nonetheless
  they caused difficulties for Free World forces in many parts of South Vietnam
  – officially called the Republic of Vietnam (RVN). While the VC hiding in
  tunnels were relatively harmless, for the moment anyway, they allowed the
  Infantrymen of the 25th
  Infantry Division sweep though
  a village in the Iron Triangle
  east of Cu Chi. The villager,
  making a point of ignoring 
  the Americans, could well have
  camouflaged a tunnel entrance
  after the local VC ducked into it.
  (25th Infantry Division
  Museum)
  TUNNEL RAT IN VIETNAM
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  5
  VC to hide and then fight another day. Tunnels also served as hiding places
  for weapons, ammunition, food, and supplies, and provided command
  centers, aid stations, hospitals, repair shops, classrooms, and other facilities.
  The main problem was that the tunnels rendered search-and-destroy
  missions ineffective. Once Free World forces had “cleared” an area, the VC
  emerged from their tunnels and continued their activities. It was also irksome
  for Free World troops to know that the enemy was hiding just feet away and
  were unreachable. Efforts were made to detect tunnel entrances and air vents.
  Explosives might be placed in discovered entrances, but that accomplished
  little in the more extensive complexes owing to hidden exits allowing escape,
  air and water locks to dampen blast concussion, angular turns, and other
  protective measures.
  To catch a rat, set a rat, or a ferret. It did little good to learn how to detect
  tunnel entrances and air vents and collapse entrances, but not to ferret out the
  enemy. Someone had to go in and get them. That was not the tunnel rats’
  main objective, however. It was important to learn just how extensive a tunnel
  complex was; this did not mean that the entire system had to be explored, but
  at least an idea gleaned as to its extent. This allowed more effective operations
  to be conducted in the future. More importantly, weapons, munitions,
  supplies, and documents had to be recovered or destroyed. Efforts were made
  to destroy tunnels to some degree, thereby preventing their continued use. 
  When the extent of the tunnels in Vietnam was realized, it was discovered
  that the Army of the Republic of Vietnam (ARVN) had known of them for
  some time. However, they had not realized their scale. This is understandable
  because they had never sent anyone into them, it being considered suicidal.
  It was also found that while scout dogs could sometimes detect tunnel
  entrances, they absolutely refused to enter them.
  At first, infantrymen volunteered to enter the tunnels: extremely gusty
  infantrymen armed with only pistols and flashlights. The “tunnel runners”
  were born. The Australians originally called them “tunnel ferrets.” They
  came to be known simply as “tunnel rats,” with the unofficial motto of Non
  Gratum Anus Rodentum – “Not Worth a Rat’s Ass.” A slogan, indicating
  the tunnel rats’ willingness to help out in a dangerous situation, was, “Don’t
  you fear, the tunnel rats are here.”
  ABOVE LEFT
  An old truck tire in a village
  junk heap was used to conceal
  a tunnel entrance. It had had
  other scrap and debris piled
  atop it. (25th Infantry Division
  Museum)
  ABOVE
  Reconnaissance platoon
  members (note the tiger-stripe
  and woodlands camouflage
  uniforms) of the 25th Infantry
  Division pass rope down 
  to a tunnel rat. This tunnel 
  is unusual as it was set in a
  relatively open cultivated 
  field. (25th Infantry Division
  Museum)
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  6
  CHRONOLOGY
  1945
  21 July 
  Vietnam divided at the 17th Parallel after the French withdraw.
  1955
  March
  First US military advisors arrive in Vietnam.
  1959
  January
  North Vietnam issues resolution that changes its “political
  struggle” in South Vietnam to an “armed struggle.”
  May
  North Vietnam begins major improvements to the Ho Chi Minh
  Trail in order to supply its struggle in the south.
  1960
  December
  National Liberation Front (Viet Cong) is formed.
  1962
  6 February 
  Military Assistance Command, Vietnam (MACV), formed to
  control all US armed forces in RVN.
  1964
  2–4 August 
  Destroyers USS Maddox and USS C. Turner Joy are allegedly
  attacked by North Vietnamese torpedo boats in the Gulf of
  Tonkin.
  7 August 
  US Congress passes Gulf of Tonkin Resolution to counter North
  Vietnamese aggression.
  1965
  7 February 
  VC attacks US installations in Pleiku. Air attacks on North
  Vietnam are authorized, which commence on February 24.
  8 March 
  First US Marine ground combat troops arrive in RVN.
  6 April 
  US ground troops are authorized to conduct offensive
  operations.
  7 May 
  First US Army conventional ground combat troops arrive in
  RVN (173rd Airborne Brigade).
  30 July
  US Army, Vietnam (USARV), is formed to control Army forces.
  22 August 
  First US combat engineer battalion (70th) arrives in RVN.
  11 September 
  1st Cavalry Division (Airmobile) arrives in RVN.
  14 September 
  First Royal Australian Engineers unit (3 Troop, 1 Field
  Squadron) arrives in RVN.
  2 October 
  1st Infantry Division arrives in RVN.
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  7
  8 October 
  First use of Mity Mite sprayer to fill tunnels with tear gas 
  (5th ARVN Infantry Division).
  1966
  8–14 January 
  Operation Crimp, the first major effort to clear the Cu Chi
  area, where extensive tunnel systems were discovered.
  8 January 
  First use of tear-gas barrel bombs dropped from CH-47
  helicopters (1st Cavalry Division).
  28 March 
  25th Infantry Division arrives in RVN.
  25 September 
  4th Infantry Division arrives in RVN.
  16 December 
  9th Infantry Division arrives in RVN.
  1967
  8–26 January 
  Operation Cedar Falls, in which the extent of the Cu Chi
  tunnels is fully realized.
  25 September 
  Americal Division activated in RVN.
  19 November 
  101st Airborne Division arrives in RVN.
  1968
  30 January 
  VC and NVA initiate the Tet Offensive, which ends February 26.
  31 March 
  US Government announces de-escalation of its war effort and
  halts bombing of North Vietnam.
  12 May 
  Peace talks begin in Paris.
  1969
  8 June 
  US initiates Vietnamization program to completely turn the war
  effort over to RVN forces.
  1970
  29 April 
  Offensive operations into Cambodia to neutralize NVA/VC
  sanctuaries.
  1973
  15 January 
  US announces halt to all offensive ground action.
  27 January 
  Ceasefire agreement is signed in Paris, and US conscription ceases.
  29 March 
  Last US troops are withdrawn from RVN and MACV is
  disbanded.
  1975
  29 April 
  The US embassy in Saigon is evacuated.
  30 April 
  Saigon falls to NVA forces.
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  8
  RECRUITMENT
  Tunnel rats were recruited in exactly the same way as other soldiers; their
  tunnel-exploration activities were in addition to whatever basic military
  occupation they engaged in day to day. The initial recruitment of tunnel rats
  is therefore identical to that of “normal” soldiers, which indeed all tunnel
  rats were. During the Vietnam War, men might have been conscripted for
  two years or voluntarily enlist for three. It was an unpopular war, but that did
  not mean that the majority of soldiers, whether drafted or volunteers, had a
  negative attitude. There were many, including draftees, who gave it their best.
  The highest demand was for infantrymen. With nine to 11 infantry battalions
  per division and four in separate brigades, a good many soldiers were
  assigned as infantrymen regardless of what their preference may have been.
  Contrary to popular conception, neither the average soldier nor the
  majority of soldiers in Vietnam were draftees. Approximately two-thirds were
  volunteers, though many had probably hoped not to be deployed to Vietnam.
  Coincidently, two-thirds of the soldiers who served in World War II were
  draftees. Approximately 70 percent of those killed in action in Vietnam were
  volunteers. It is often said that the average age of infantrymen in Vietnam
  was 19. It was actually 22. It would have been higher if the full complement
  of mid- and senior-grade NCOs were available, but since there were shortages
  of those grades, the average age of infantrymen was much lower, but not as
  low as 19. Recruitment and training of infantrymen is addressed in Warrior
  98: US Army Infantryman in Vietnam 1965–73 (Osprey: Oxford, 2005).
  As there were no tunnel rat units or standardized practices, tunnel rats
  were “recruited” in different ways. Often it was simply a call for volunteers
  on the spot. Tunnels or caves were discovered and they needed to be checked.
  Some tunnel rats preformed the job only one or two times, as it became
  necessary. It was simply a matter of who was available and willing. Often
  there was no intent to explore or plot tunnel routes, but simply to determine
  if they were occupied and to recover any weapons, munitions, or documents.
  In most cases, tunnel rats were infantrymen, engineers, cavalry scouts, and
  chemical specialists, who carried out this dangerous mission in addition to
  The camouflage has been
  stripped from this bunker.
  Several such bunkers were
  sometimes linked together by
  tunnels or simple shallow crawl
  trenches covered by
  camouflage. (Tom
  Laemlein/Armor Plate Press)
  © Osprey Publishing • www.ospreypublishing.com
  
  9
  whatever other duties they usually preformed. There were instances when
  tunnel rats were formed into teams to be available on-call when necessary.
  These might be assembled into teams in the battalion headquarters company.
  More often than not, tunnel rat teams were ad hoc groups of two to six men.
  The qualities needed to be tunnel rats were evident. The most obvious was
  that they had to be immune to claustrophobia, but that in itself was not
  enough. They had to be able to crawl through a narrow tunnel for prolonged
  periods in absolute darkness, and be unaffected by highly probable encounters
  with bugs, snakes, rodents, and other vermin, as well as deadly close combat
  in the worst possible conditions. They had to crawl through mud and flooded
  tunnels, search for booby traps, deal with choking smoke and tear gas (known
  as CS), and endure the stench of the dead and of human waste. It is one thing
  to crawl through a small tunnel in pitch blackness, and another to plunge into
  a water lock (a portion of flooded tunnel) and trust that it was not too long
  only because it was assumed that a VC could hold his breath for only a short
  time as well. All too often it could be a dead end, and it would then be a long
  way back to the entrance – moving backwards. Tunnel rats may have worn
  gasmasks to protect them from tear gas, but tear gas also affected moist skin
  and there was no protection from that. There was also the danger of oxygen
  starvation. Tunnel rats required acute hearing, something that many troops
  that had been in combat for even a short time suffered a deficiency in. They
  had to be able to detect the faintest sounds of movement.
  As with any volunteer job in the Army, one could “un-volunteer.” One
  does not of course un-volunteer from combat, but tunnel exploration was
  obviously a special case. It offered a high possibility of developing severe
  claustrophobia, which was something that could completely incapacitate a
  soldier underground. Tunnel rats had to be completely willing and able to
  undertake the job. Physically, they needed to be of a small stature. The job
  also required agility, strength, and the ability to perform difficult tasks in
  cramped confines. This included probing, digging, forcing open trapdoors,
  disarming booby traps, fastening ropes to material being recovered, and
  emplacing demolitions.
  This tunnel entrance proves to
  be a tight fit for a 25th Infantry
  Division tunnel rat. Helmets
  were sometimes worn during
  the initial entry, but often
  discarded because of the
  confined space. (25th Infantry
  Division Museum)
  © Osprey Publishing • www.ospreypublishing.com
  
  10
  TRAINING
  There was no Military Occupation Specialty (MOS) for tunnel rats. They were
  mostly combat engineers (12B), infantryman (11B), armored reconnaissance
  specialists (11D), and chemical-operations specialists (54A). Mortar (11C)
  and antiarmor (11H) crewmen often found themselves underemployed and
  pressed as 11B infantrymen. They too were a source of tunnel rats. Both Basic
  Combat Training (BCT) and Advanced Individual Training (AIT) taught a
  variety of skills that would be valuable to future tunnel rats. It was also found
  that having men with different MOSs within a tunnel rat team brought a
  broad range of experience, which proved very useful in the field.
  Basic Combat Training
  All US soldiers, from cooks to infantrymen, undertook the eight-week BCT
  course, regardless of their future MOS. This was preceded by “Zero Week,”
  in which administrative processing, inoculations, testing, and uniform issue
  was conducted. BCT was conducted at over 20 training centers across the
  country. The goals of BCT was to instill military discipline and confidence,
  get recruits in physical shape, learn dismounted drill, learn to live in the field,
  qualify with the M14 rifle (83 hours of training and firing), live and operate
  as part of a unit, follow orders, and learn the rudiments of military service
  and individual combat skills. This included a wide range of subjects: hand-
  to-hand combat, bayonet fighting, chemical-warfare defense, first aid, guard
  duty, map reading, and the use of hand grenades.
  One experience in BCT of particular benefit to future tunnel rats was the
  dreaded gas chamber. This was hyped up quite a bit by drill sergeants, with
  trainees living in fear of the unavoidable event. Soldiers received only four
  hours of chemical, biological, and radiological (CBR) warfare orientation.
  This mainly entailed the use of the M17 protective mask, simply called the
  “gasmask.” The M17 was made of a black rubber-like plastic face-piece with
  large bug-like eyepieces, providing a relatively wide field of vision. Rather
  than an awkward air-filter canister on the side of the face piece or the snout,
  low-profile internal filters were fitted on both cheeks. The voice-emitter,
  allowing verbal communication, was set in the snout. Adjustable web straps
  allowed the mask to be fitted round the back of the head; it would be worn
  under the helmet. The mask was carried in a canvas case secured to the
  soldier’s left hip by shoulder and leg straps. It was hot to wear and caused
  sweating in even mild weather, restricted vision somewhat, and was
  claustrophobic to wear for some men.
  Trainees leaned that when a gas alarm was sounded one had to stop
  breathing, remove the mask from the case, and don it in a matter of seconds.
  They were then to clear the mask by slapping their hands over the filters and
  exhaling sharply. This prevented the exhaled air from being blown through
  the filters, but blew air and contaminates out from under the face-piece’s
  edges instead. Theoretically, the soldier could now breathe normally, although
  it was akin to breathing with a towel wrapped over one’s face. If running or
  exerting oneself, it was difficult to draw in enough air.
  The M17 mask offered protection from chemical-warfare agents (nerve,
  choking, blistering, blood, and irritant agents), most biological agents, and
  radioactive contaminates. What it did not protect from was oxygen
  starvation. This meant that a large volume of smoke (including that from
  smoke grenades) and tear gas in a confined space could suffocate a person,
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  11
  as smoke and tear gas displace oxygen. This would require an extremely
  concentrated volume of smoke or tear gas for a prolonged period.
  The gas chamber was simply a small cinderblock building with two
  airtight rooms set in a remote training area. It had steel entry and exit doors
  on opposite ends and no windows. The trainees were motivated with war
  chants and a great deal of yelling to build up courage. They entered one room
  wearing their masks. The room was filled with diluted chlorine gas. Even if
  inhaled, the worst that could happen was a mild headache. The trainees
  believed the gas was lethal. They stood against the walls of the chamber and
  were instructed to take three deep breaths to fill their lungs with oxygen.
  When given the order, they lifted their masks off their faces, continuing to
  hold their breath. Even though they were holding their breath, they could
  smell a scent like laundry bleach. When tapped by the instructor, they would
  replace their masks and clear them by blowing residual gas out the sides.
  They then filed out. The purpose was to provide self-confidence and
  confidence in the use of the mask.
  The tear-gas chamber was a different matter. Tear-gas pellets were placed
  in a can in the chamber’s center and burned with a heat tablet to fill the room
  with vapor. Trainees with masks donned ran into the tear-gas-filled room and
  lined up against the walls. On order, they removed their masks and were told
  to breathe it in. The effects were immediate, with tears, coughing, gagging,
  and free-flowing mucus and saliva. The mask-wearing drill sergeants ordered
  each man to recite his name, rank, service number, and date of birth, or
  sometimes to sing a song. This ensured that they remained in the chamber
  sufficiently long to experience the effects. They were not told to re-don their
  Bunkers such as these served as
  bomb shelters with roofs 4ft to
  6ft thick made of crisscrossed
  logs and layers of earth. They
  had to be entered with care,
  because of the possibility of
  encountering booby traps.
  (Tom Laemlein/Armor Plate
  Press)
  © Osprey Publishing • www.ospreypublishing.com
  
  12
  masks, but to place their left hand on the shoulder of the man in front and
  follow him out when ordered. Clearing the mask in the normal manner would
  do nothing for the CS powder, which was already in the eyes, nose and
  mouth; it would only make it worse. Drill instructors watched trainees closely
  for any adverse reaction and medics were on-hand with oxygen.
  Tear-gas use and effects
  What is known as CS-1 riot-control agent is also commonly called “tear gas.” “CS” is merely a code identiﬁer
  and not an abbreviation. It is also described as an irritant agent and an incapacitating agent. CS replaced 
  CN (chloracetophenone) in the early 1960s. It is odorless, but there is a faint burnt smell from burning-type
  CS munitions.
  It was one of the tunnel rats’ main tools. It causes extreme irritation to the eyes, nose, throat, and lungs.
  The eyes burn severely and extensive tear ﬂow results. It is virtually impossible to keep the eyes open other
  than for a few blinking moments; some individuals are unable to open their eyes at all. The need to rub the
  eyes is impossible to avoid and only increases the burning sensation. The effects are accompanied by
  excessive mucus ﬂow from the nose and saliva from the mouth. Moist skin areas, especially the underarms
  and groin, itch and burn. Sunburned areas are also affected. Rubbing exposed skin areas only rubs in the CS
  powder. In extreme and prolonged instances of inhaling CS causes respiratory problems. Many Vietnamese
  thought tear gas would cause some form of illness, but could not say what that illness or its symptoms were.
  Individuals experiencing CS for the ﬁrst time can easily panic, especially if in a dark conﬁned space. This is
  another reason why US soldiers were exposed to CS in training, to give them the experience and conﬁdence
  to cope with it.
  The “gas” is actually an ultra microﬁne powder and not a gas. The powder can settle on the ground and
  vegetation and when disturbed will rise up and affect anyone in the area. Particles will also cling to tunnel
  walls. It usually loses its potency within six days, but can last longer in dry weather.
  Powdered CS was dispersed by dropping 55-gallon drums from helicopters, attached to explosives and
  detonated inside tunnels, or dispersed by Mity Mite blowers into tunnels. Limited use was made of 105mm
  howitzer XM629, 4.2in. mortar XM630, and 40mm grenade-launcher XM651 CS projectiles.
  Infantrymen wearing M17
  protective masks. The radio
  operator with his sleeves rolled
  up appears to be feeling the
  effects of the micro-pulverized
  CS burning his armpits. Note
  the coiled sling ropes on the
  two un-masked men. (Tom
  Laemlein/Armor Plate Press)
  © Osprey Publishing • www.ospreypublishing.com
  
  13
  A straightforward description of the experience provides a trainee’s view
  of the effects of CS:
  Pulling the mask up when ordered, you first smell a burnt dusty odor. We of
  course held our breath as long as possible and kept our eyes shut. Since we had
  to shout our name, rank, and number, it was unavoidable. In seconds I felt my
  eyes burning and I could feel burning in my nose and mouth. It got worse in
  seconds and some guys tried to run for the door with sergeants grabbing them
  and ordering them to freeze. Most stuck it out. In a few more seconds my eyes
  were burning so bad that it took everything I had to not rub them. Snot started
  running from my nose like I’ve never seen and I was drooling saliva like a dog
  on a hot day. Everything burned, even my armpits. Everyone was bending over
  coughing and gagging, spitting and yelling at the top of their lungs. I couldn’t see
  a thing and my eyes were burning and stinging like mad. No one panicked, but
  when they said, “get out of here,” there was no hesitation. Everyone kept their
  arm on the man in front and a sergeant led us out. Everyone rushed away from
  the building and faced into the wind as we’d been told. We started washing our
  eyes with canteens and they had more water for us. The sergeants were checking
  on everyone and asking if we were okay, as well as keeping us from running
  into trees. It was only a few minutes before we got over it and then everyone was
  laughing, joking, and talking. I remember a sergeant telling us not to wear these
  fatigues again until they were washed. It was bad and a little scary, but we felt
  like we had done something difficult and most were proud of it.
  Graduation from BCT was a milestone regardless of whether trainees had
  considered it a good, bad, or indifferent experience. A “cycle book” filled
  with photos of their comrades and training events was given to each man.
  They were now soldiers, but they still had their MOS training to accomplish.
  Usually trainees undertook BCT at the same post they would undertake
  infantry AIT (this stands for “Advanced Individual Training,” not “Advanced
  Infantry Training” as is sometimes reported). However, it was not uncommon
  for them to take BCT at one post and then be transferred to another post to
  undertake infantry AIT or another MOS.
  Engineers prepare 2½lb M5A1
  C4 demolition charges and link
  them to detcord with half-hitch
  knots. The man to the right is
  wearing his helmet camouflage
  cover with the brown side out,
  which is unusual. (1st Cavalry
  Division Museum)
  © Osprey Publishing • www.ospreypublishing.com
  
  14
  Infantry Advanced Individual Training
  This was where soldiers learned the skills of their job, and were awarded an
  MOS. Training for the three infantry MOSs – 11B (light infantryman), 11C
  (indirect-fire [mortar] crewman), and 11H (antiarmor [recoilless rifle]
  crewman) – was conducted at Fort Campbell, Kentucky; Fort Dix, New Jersey;
  Fort Gordon, Georgia; Fort McClellan, Alabama; Fort Ord, California; and
  Fort Polk, Louisiana. Combat engineer training was undertaken at Fort
  Leonard Wood, Missouri, and chemical-warfare specialists were trained at
  Fort McClellan, Alabama. Armored cavalry scouts were trained at Fort Knox,
  Kentucky, at the Armor School.
  Infantry training took eight weeks and included individual tactical skills,
  combat and reconnaissance patrolling, squad and platoon offensive and
  defensive tactics, live-fire tactical exercises, and qualification with the M14A1
  automatic rifle, M60 machine gun, and .45-cal. pistol. There was also
  familiarization firing of the 40mm M79 grenade launcher, 90mm M67
  recoilless rifle, 3.5in. M20A1B1 rocket launcher (bazooka), and the M72
  LAW. A brief amount of training time was spent on the laying, detecting, and
  removal of landmines as well as detecting and setting booby traps. This was
  accomplished using US firing devices and explosive items, with little
  orientation on the many and varied VC/NVA booby traps. Tunnel rats
  encountered many traps and explosives in tunnels, and so this training was
  especially valuable for them.
  Most infantry AIT training centers were rated “Vietnam-oriented.” The
  exception was Fort Dix, which trained personnel destined for assignments other
  than Vietnam. “Vietnam-oriented” meant that a small Vietnamese village was
  erected, sometimes with adjacent replica rice paddies. One was even built at
  Fort Dix even though it was not a Vietnam-oriented training center.
  Trainees conducted an exercise where they cordoned off the village and
  searched it. Various simple booby traps, hiding places, and defenses and
  perimeter obstacles were found in these villages, including perimeter berms
  The replica VC village at
  Tigerland, Fort Polk, Louisiana.
  Clockwise from upper left: The
  village’s flooded defensive
  moat with blunt punji stakes;
  the interior of a thatch hooch;
  the intersection of the three
  corrugated steel-lined tunnels
  with a hidden entrance above
  and on each end; a trapdoor
  hidden beneath a table. (Fort
  Polk Museum)
  © Osprey Publishing • www.ospreypublishing.com
  
  15
  and ditches filled with fake punji stakes. Trainees found it humorous when
  conducting simulated assaults on a “Vietnamese” village in the winter months
  as they slid across frozen rice paddies. Some centers went so far as to provide
  a simple tunnel system.
  The author experienced the replicated Vietnamese village’s tunnel system
  at Peason Ridge Training Area north of Fort Polk, Louisiana, in 1967. Other
  than being underground, it bore little resemblance to actual VC tunnel
  systems. It had a Y-shaped layout and was less than 100ft long, with three
  unimaginatively hidden entrances inside hooches. It was about 5ft below
  ground and had no air vents, water or air locks, sharp angular turns, hidden
  passages, side rooms, or any of the facilities and amenities found in actual
  complexes. It was lined with 4ft-diameter corrugated steel culvert pipe, which
  was much more spacious the 2½ft-wide and 3–4ft-high or smaller tunnels
  typically found in Vietnam. Another problem was that the steel-lined tunnels
  prevented troops from practicing plotting the route using a magnetic compass.
  The area’s high water table ensured that it partially flooded after rains.
  Other than a day or two in the Vietnamese village there was little actual
  Vietnam-orientated training except for some additional ambush and counter-
  ambush exercises. However, basic conventional tactics provided the basis of
  small-unit tactics in Vietnam, which were modified for the non-linear tropical
  battlefield (see Elite 186: Vietnam Infantry Tactics, Osprey: Oxford, 2011).
  Combat engineer Advanced Individual Training
  Tunnel rats used explosives extensively to collapse tunnel entrances and
  destroy caches of enemy equipment, and so combat engineer training was
  especially valuable. The eight-week-long combat engineer AIT was conducted
  at Fort Leonard Wood, Missouri. It was better known at “Fort Lost in the
  Woods Misery” or “Little Korea” in reference to the harsh winters of that
  country. The training covered many of the same subjects as that for infantry
  (engineers had a secondary role as infantry and had to be able to defend their
  worksites), but with less emphasis on tactics and live-fire exercises. Engineer
  training concentrated on land navigation, map reading, rigging (working with
  ropes and block and tackle), knot-tying, the use of hand and power tools,
  Combat engineers learned a
  great many skills during AIT at
  Fort Leonard Wood, Missouri,
  many of which proved useful to
  tunnel rats. Here trainees learn
  how to rig a block and tackle.
  (US Army)
  © Osprey Publishing • www.ospreypublishing.com
  
  the use of the pneumatic jackhammer, the laying of steel matting for airstrips
  and roads, constructing timber bridges, erecting panel and floating bridges,
  small-boat handling, constructing poncho rafts, constructing barbed-wire
  obstacles and field fortifications, camouflage, mine laying and clearance, and
  A
  ENGINEER DEMOLITIONS TRAINING
  The staff sergeant here has prepared a display of demolition materials most commonly used in
  Vietnam. He wears the stateside fatigue uniform with combat boots and a white-painted helmet
  liner and instructor armband (“INSTR”) identifying him as being on the Demolition Committee.
  Training centers wore the shoulder insignia of the army area in which they were located, which in
  this example is Fifth Army. In July 1966 the name and US Army tapes were ordered changed to
  black on olive drab, but it took almost two years for the changeover to take place.
  The ¼lb TNT charge (1) was mainly used for training and was not commonly employed in combat.
  The ½lb TNT charge (2) was less widely used than the 1lb TNT charge (3), which was widely used,
  but in general C4 saw much more use than TNT, especially since TNT produced dangerous fumes
  underground. The TNT charges were contained in water-resistant fiberboard covers with metal end
  caps and a cap well in one end. The 2½lb M5A1 C4 demolition block (4) had clear plastic covers and
  white plastic ends with cap wells in both. M5A1 blocks were replaced by the M112, but remaining
  stocks were expended in Vietnam. The 1¼lb (500g) M112 C4 demolition charge (5) was covered in
  Mylar with an adhesive backing, and was by far the most frequently used charge in the field. The
  M118 C4 demolition charge (6) held four ½lb, ½in.-thick sheet charges. The M183 demolition-
  charge assembly (7) held 16 M112 charges and four priming assemblies (5ft of detcord with an RDX
  booster on each end) in an M183 haversack. They could be used as individual charges or as a
  satchel charge. Detcord (8) was used to link together demolition charges for simultaneous
  detonation; it was not a timed safety fuse. The 15lb M2A3 shaped-charge (9) held 11½lb of
  Composition A3. It was contained in a fiberboard casing with a 6in. base that attached to the lower
  end, providing standoff from the target. It could penetrate 36in. of reinforced concrete. The 40lb
  M3 shaped charge (10) with detachable 15in legs could punch through 60in. of concrete. The
  ammonium-nitrate 40lb cratering charge (11) contained 40lb of Composition H6 and was used to
  blast large craters in roads and to blow apart obstacles. It proved very useful for destroying tunnels.
  Earlier ammonium-nitrate-filled charges were also used. The M1A2 bangalore torpedo (12) was 5ft
  long and contained 10½lb of Composition B4. Used for breaching wire obstacles and minefields,
  they could be attached end-to-end up to a total length of 200ft. In Vietnam they were used to blast
  paths through dense bamboo thickets. Most of the charges shown here are still in use today.
  16
  Among the many jobs assigned
  to engineers in Vietnam, an
  important one was clearing
  vegetation in order to create
  firebases, fields of fire, and
  helicopter landing and pickup
  zones. Besides demolitions
  materials and bulldozers,
  machetes and chainsaws were
  used. Chainsaws were also
  useful for clearing vegetation
  and manmade structures from
  around tunnel entrances. (Tom
  Laemlein/Armor Plate Press)
  © Osprey Publishing • www.ospreypublishing.com
  
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  operating AN/PRS-3 mine detectors. Many of these skills would prove
  invaluable to tunnel rats. Almost a week was spent on demolitions training,
  learning about all the different explosives, materials, and equipment,
  including electric and non-electric firing systems, and how to calculate and
  emplace charges on different types of targets. Weapons training included the
  M79 grenade launcher, M60 machine gun, 3.5in. bazooka, and M72 LAW.
  APPEARANCE
  There were no height or weight requirements for infantrymen and engineers,
  although they were required to be in first-rate physical condition: what was
  known as a “picket-fence profile,” that is, “111111.” The PULHES profile
  included: P – Physical capacity or stamina, U – Upper extremities, L – Lower
  extremities, H – Hearing and ears, E – Eyes, and S – Psychiatric. A “2” or “3”
  in any of these six categories disqualified an individual from the combat arms
  (infantry, armor, combat engineers, and artillery). An exception was a “2” in
  hearing for artillerymen, the reasoning being that they would eventually
  damage their hearing anyway.
  Most tunnel rats were of small stature. The average Vietnamese male was
  5ft 1in. to 5ft 4in. tall, and weighed 110–122lb. The average American soldier
  was 5ft 8in. tall and weighed 120–180lb; he would have a difficult time
  navigating tunnels custom built for Vietnamese men. Obviously, smaller-
  statured Americans made better tunnel rats, but larger-framed tunnel rats
  were not unknown. Regardless of height, they needed to be limber.
  Combat engineer training
  included a great deal of
  demolitions training, which
  proved extremely valuable 
  in tunnel-destruction work.
  Here an instructor points out
  the characteristics of the 40lb
  M3A1 shaped-charge, used 
  for blasting holes through
  concrete structures. (US Army)
  18
  © Osprey Publishing • www.ospreypublishing.com
  
  Into the ground
  There was no prescribed tunnel rat “uniform.”
  Before descending into the abyss the tunnel rat
  prepared for the job by removing all of his web
  gear and some of his “surface uniform.” The
  jungle fatigue uniform consisted of the commonly
  worn pants and shirt. Many tunnel rats removed
  their shirt, as its cargo pockets and loose sleeves
  could easily snag on obstructions. If the shirt was
  retained, the sleeves were usually worn down to
  protect the elbows when crawling, as they snagged
  less than rolled-up sleeves. Some men tucked their
  shirt into their pants. Those removing their shirts
  may have worn their undershirt while others went
  bare-chested. Many men did not wear undershirts
  or even underwear, owning to sweat retention,
  which resulted in rashes and chaffing, especially in the groin and underarm
  areas. Such rashes were uncomfortable and could become infected.
  Occasionally men reduced the naturally baggy jungle-fatigue pants by
  securing the lower legs with “550 cord,” web straps, or green duct tape.
  A tunnel rat prepares to enter 
  a tunnel. Note the olive-drab
  towel used as a “drive-on rag”
  around the neck to mop up
  sweat and clean off mud and
  dirt. (25th Infantry Division
  Museum)
  19
  The tight confines of a 
  Hobo Woods tunnel are
  demonstrated here by a 
  25th Infantry Division tunnel
  rat equipped with his two most
  common and valuable tools, 
  an MX-199/U flashlight and 
  a .45-cal. Colt M1911A1 pistol.
  (Tom Laemlein/Armor Plate
  Press)
  © Osprey Publishing • www.ospreypublishing.com
  
  An issue olive-drab towel or a triangular bandage was often worn by
  soldiers in the field to mop up sweat. Tunnel rats found it useful to wipe sweat
  and dust off their faces or clean mud off their hands to allow them to do
  delicate work. Wristwatches, dog tags, and rings were removed to prevent
  snagging. They carried grenade arming pins to deactivate booby-trapped
  grenades. US grenade pins would fit into Soviet and Chinese grenades.
  Most tunnel rats went in bareheaded so as to have unrestricted vision and
  hearing. It meant that one could expect some bumps on the head, but clear
  vision and hearing were essential. Some occasionally wore steel helmets and
  others just the helmet liner as a lighter alternative. Hair was generally worn
  short for hygienic reasons in the hot and humid climate, but longish hair was
  not unknown. Kneepads and/or gloves may have been worn. Jungle boots
  were typically worn with the pants bloused into them. On rare instances
  tennis shoes were worn. It was common to douse oneself with insect repellent
  before entering a tunnel in order to ward off leeches, mosquitoes, spiders,
  scorpions, fleas, ants, and other creepy crawlies.
  B
  COMBAT ENGINEER
  Combat engineers appeared little different from infantrymen. This engineer, undertaking a light
  construction project, wears the M1 steel helmet (with grenade-arming pins in the camouflage
  band, for neutralizing booby traps) and the M1952 body-armor vest. He has removed his jungle
  fatigue shirt, owing to the heat. He is outfitted with basic M1956 web gear with two ammunition
  pouches holding two 20-round magazines each; infantrymen typically carried more. An M61
  fragmentation grenade is hooked on his vest. This was the same as the M26A1, but had a wire
  safety clip securing the arming lever. Called a “jungle clip,” it prevented the grenade from arming
  if the pin was snagged on vegetation. He is armed with an M14 rifle, but engineer units received
  M16A1 rifles soon after the infantry did. He carries a D-handle shovel, an essential tool of war for 
  a combat engineer. Other gear includes a 3-gallon canvas bucket (1), work gloves (2), M1938 wire
  cutters (3), an 18in. machete with plastic scabbards (4), and a 500ft roll of engineer tape (5). This
  was a 2in.-wide white, non-adhesive tape used to mark lanes through minefields. It saw practical
  application when used to mark tent guy lines, barbed wire, open holes, and anything else a
  soldier could trip on in firebases at night. Short strips would be tied to vegetation to mark
  discovered tunnel entrances, air vents, mines, and booby traps. He also carries a stainless-steel
  utility pocketknife, commonly called a “demo knife” (6). It had a 3in. knife blade, a
  screwdriver/bottle cap-lifter, a can opener, and an awl (punch). The M2 cap crimper (7) (also
  known as a “fuse crimper”), besides crimping blasting caps on time fuse and detcord, provided 
  a screwdriver, a punch for making blasting cap holes in C4, and a fuse and detcord cutter. One 
  of many variants of unofficial Tunnel Rat patches is shown at (8). It depicted a flashlight-and-
  pistol-armed rat and was inscribed Non Gratum Anus Rodentum (Not Worth A Rat’s Ass).
  20
  ABOVE
  Infantrymen lower a tunnel 
  rat into an entrance shaft. The
  VC probably used a bamboo
  ladder, which may have been
  taken into the tunnel with
  them. (25th Infantry Division
  Museum)
  ABOVE RIGHT
  A 1st Cavalry Division volunteer
  discards his M16A1 rifle and
  helmet. He wears an M17
  protective mask case on his 
  left hip. This tunnel entrance is
  hidden in a pig pen, something
  that a soldier would be
  reluctant to search. (Tom
  Laemlein/Armor Plate Press)
  © Osprey Publishing • www.ospreypublishing.com
  
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  EQUIPMENT AND WEAPONS
  Tunnel rats needed light and compact weapons, preferably with a sound
  suppressor. A single gunshot in a tunnel’s confinement was excruciatingly
  loud and damaged one’s hearing. Firing a .45-cal. pistol inside a tight-fitting
  tunnel was deafeningly painful and caused permanent hearing damage. 
  It literally feels like nails are driven into one’s ears. They were used only as a
  last resort. Few suppressed weapons were available, and standard handguns
  were commonly used. Hearing protection could be worn, but it was essential
  for tunnel rats to be able to hear the faintest sounds of movement in the pitch-
  black tunnels, so they typically went without. Most items of equipment used
  for tunnel exploration and destruction were readily available standard-issue
  items, though sometimes used in a manner different than that for which they
  were originally intended.
  Tunnel rat weapons
  The standard weapons carried by most infantrymen were unsuitable for use
  in the extremely confined spaces where tunnel rats could expect to fight, being
  much too large to use conveniently, if at all. As tunnel rats usually carried a
  flashlight with them into tunnel complexes, it was important to be able to use
  something that could be aimed and fired with one hand. For these reasons,
  handguns were the weapons of choice.
  The most common of these was the standard-issue Colt .45-cal. M1911A1
  pistol with a seven-round magazine. They were readily available, with almost
  30 in a rifle company and at least a dozen in an engineer company. Some use
  was made of Smith & Wesson Model 10 and Colt Police Positive Special
  revolvers, which were normally issued to aviators. Both held six relatively
  underpowered .38-cal. Special rounds. They made almost as loud a report as
  the .45-cal. Some use was made of privately purchased .38-cal. Special and
  .357-cal. Magnum revolvers and .45-cal. ACP and 9mm pistols of various
  makes. Occasionally, .30-cal. M2 carbines with the barrel cut back to the
  forearm and the butt stock sawn off leaving a pistol grip were used.
  Hi-Standard .22-cal. Long Rifle Model HD semi-automatic pistols with a 
  10-round magazines were occasionally issued. Sometimes the Model HDM
  with a non-removable silencer was provided – originally acquired by the
  Office of Strategic Services (OSS) in 1943. The silencer had a life of about 
  200 rounds, which was not a serious drawback as
  they were so seldom fired. Another .22-cal. Long
  Rifle semi-automatic seeing some use was the
  Ruger Mk I Target pistol, which also used a 10-
  round magazine. These had originally been used
  as training and match pistols. A .22-cal. firearm
  is not a potent weapon, but at ranges of a few feet
  and with repeated rapid shots, it did the job.
  In 1966 the Army issued six experimental
  tunnel-exploration kits. With the kits came an
  S&W .38-cal. Special Model 10 revolver with a
  silencer and aiming light. The aiming light was
  unnecessary and the silencer too long, making the
  weapon unbalanced. Silencers do not really work
  on revolvers, owning to the slight gap between the
  cylinder and the rear end of the barrel, but they
  22
  An automatic rifleman armed
  with a 7.62mm M14(M)
  automatic rifle fitted with an
  M6 bayonet coaxes a VC out of
  a tunnel. Mats and corrugated
  tin had been used to cover the
  hole. (Tom Laemlein/Armor
  Plate Press)
  © Osprey Publishing • www.ospreypublishing.com
  
  did greatly reduce the sharp report and ear damage. Another problem was
  that the silencer was designed to be used with half-load rounds, but only full-
  load M41 rounds were available in Vietnam.
  A total of 75 specially modified S&W Model 29 revolvers were issued in
  1969. They fired a special .40-cal. shot cartridge designed to make a report no
  louder than a .22-cal. Long Rifle. The shot cartridges held 15 7.5-grain
  tungsten steel pellets in a plastic sabot (a .117-cal. BB weighs 5–6 grains) and
  used the gas seal piston concept to reduce its noise signature. The revolvers
  were designated the Quiet Special Purpose Revolver (QSPR), also known as
  “tunnel revolvers” or “tunnel guns.” It had no sights, and had a 1.37in.-long
  (35mm) smoothbore barrel with a 30ft range. These revolvers were inexplicitly
  withdrawn after six months, probably because they performed poorly owing
  to the unusual cartridge system, which may not have been sufficiently lethal.
  Even its reduced report was too loud in a tunnel’s confines.
  Hand grenades included M26 “lemon” and M67 “baseball” fragmentation
  grenades, Mk 3A2 “demolition or concussion” grenades, and M34 white
  phosphorus (“Willie Pete”) grenades. Blast and
  fragmentation grenades could not be used
  underground. Even tossing a grenade around a
  90-degree tunnel bend would create far too much
  blast over-pressure in the confined space. They
  were routinely thrown into tunnel entrances to
  clear a portion of the tunnel up to the first bend,
  making it deadly for any VC personnel to remain
  anywhere close to entrances. The concussion
  grenade, containing 8oz of TNT, was particularly
  effective for this compared to the M67
  fragmentation grenade, which contained 6.5oz of
  Composition B. With a fiber body, the Mk 3
  generated little fragmentation. M18 colored- (red,
  yellow, violet, or green) and AN-M8 white-smoke
  grenades were widely used, along with M7A2
  23
  The angular entrance to a
  tunnel has been cleared and 
  a tunnel rat prepares to enter.
  This 1st Infantry Division tunnel
  rat appears to be armed with 
  a .40-cal. Quiet Special Purpose
  Revolver based on the S&W
  Model 29. He wears a shoulder
  holster rig and holds a pen
  flashlight in his left hand. (Tom
  Laemlein/Armor Plate Press)
  Debris is shoveled away 
  from a tunnel entrance 
  after a shattering explosive
  detonation that virtually
  disintegrated the surrounding
  vegetation. (25th Infantry
  Division Museum)
  © Osprey Publishing • www.ospreypublishing.com
  
  and M7A3 riot-control grenades (see sidebar). Thermite-filled AN-M14
  incendiary grenades were used to destroy enemy equipment such as heavy
  weapons and radios. They burned at 4,330°F and could melt through steel.
  The M1A1 white-smoke pot weighed 12lb and was contained in a 5.5in-
  diameter, 8in.-high can. It had a screw-on cap with a 10-second delay friction
  igniter. It produced gray-white smoke for five to eight minutes. This could be
  pumped into tunnels via a Mity Mite blower to smoke out the occupants.
  Less used was the 30lb ABC-M5 white-smoke pot.
  Tunnel rat equipment
  Engineers and infantrymen carried much the same field equipment, which was
  made up of a rucksack and load-bearing equipment (LBE), known as “web
  gear.” Generally this consisted of a pistol belt, suspenders, two or more
  ammunition pouches, one or two canteens, a first-aid pouch, and other gear.
  Out of necessity, the tunnel rat could carry only what was absolutely necessary.
  The less encumbered he was, the better he could do his job. In tight spaces he
  needed to take up as little space as possible, and unnecessary equipment would
  only get in the way, especially when he had to be a contortionist.
  24
  CS grenades
  The ABC-M7A2 and ABC-M7A3
  riot-control hand grenades,
  commonly known as “CS” or
  “tear-gas” grenades, were
  important tools in tunnel
  warfare. These beer-can-sized
  grenades began spewing tear
  gas within two seconds after
  releasing the arming lever. 
  The M7A2 was ﬁlled with 3.5oz
  of CS in gelatin capsules with
  5.5oz of burning mixture. The
  M7A3 had 4.5oz of pelletized
  CS with 7.45oz of burning
  mixture. There were four holes
  in the grenade’s top and one
  in the bottom, through which
  burning CS escaped. They
  burned for 15–35 seconds, 
  but for 20 seconds on average.
  When ignited, the grenade
  grew extremely hot and would
  burn one’s hands if picked up;
  it would remain hot for some
  time. The M7A2 grenade
  weighed 14oz and the M7A3
  weighed 15.5oz. The M54 CS
  grenade adopted in the late
  1960s was an M7A3 with an 8–
  12-second M226 delay fuse for
  dropping from helicopters.
  Another type of riot-control
  grenade was the ABC-M25A2.
  This was an 8oz baseball-
  shaped bursting-type grenade
  with a plastic body. It was
  activated by pulling the C12
  igniter’s arming pin while
  retaining a spring-loaded
  sleeve over the top of the 
  fuse with the thumb. When
  thrown, the small button-like
  sleeve ﬂew off and the grenade
  burst in 1.4–3 seconds,
  spreading a 5m cloud of CS.
  The CS was mixed with silica
  aerogel to more effectively
  spread the tear gas. Being
  spherical and lighter, it could
  easily be chucked down a
  tunnel’s length.
  A 1st Infantry Division soldier 
  in the Iron Triangle peers into 
  a partly hidden bunker
  entrance with an M2A1-7
  portable flamethrower.
  Flamethrowers were little used
  in Vietnam owing to their 70lb
  weight when full, and the fact
  that they were expended in
  seconds. They would then 
  have to be refueled and
  repressurized using equipment
  that could not be man-packed
  through the jungle. (Tom
  Laemlein/Armor Plate Press)
  © Osprey Publishing • www.ospreypublishing.com
  
  Tunnel teams assembled kits with the necessary equipment, to which they
  added and removed items as experience dictated. The gear might be carried
  in large wooden ammunition crates, duffle bags, or aviators’ kit bags. 
  A “light” tunnel-exploration kit might consist of the following:
  • Protective masks (x2)
  • TA-1/PT field telephones (x2)
  • MX-306 telephone wire spool
  • Lensatic compasses (x2)
  • Sealed beam 12-volt flashlights (x2)
  • .22-cal. HD or Mk I pistols (x2)
  • Probing rods (12in. and 36in.)
  • Bayonets (x2)
  • Entrenching tool
  • Powdered CS (as required in cans)
  • M7A2 CS grenades (x12)
  • M18 colored-smoke grenades (x4)
  • Insect repellent (x4 cans/bottles)
  A “heavy” tunnel-exploration kit would contain more bulky equipment and
  would be employed by tunnel rats expecting to remain underground for
  extended periods. Some of these items might be:
  • Protective masks (x2)
  • Body-armor vests (x2)
  • 100ft nylon rope
  • Grappling hooks (x2)
  • TA-1/PT field telephones (x2)
  • MX-306 telephone wire spool
  • Work gloves (x2 pairs)
  • Kneepads (x2 pairs)
  • Earplugs (x2 pairs)
  • Flashlights (x6) and spare batteries
  Flashlights were essential, and the wise tunnel rat
  would carry a spare, but this was not always done.
  The main model was the MX-991/U right-angle
  flashlight. It had an olive-drab plastic waterproof
  body holding two BA-30 batteries. The switch was
  protected by a guard to prevent the operator
  accidentally turning it on or off by bumping against
  something (early models lacked switch guards).
  There was a clip on the side for attachment to web
  gear or a belt, and a carrying ring on the bottom. 
  It had a separate compartment in the battery cap,
  which contained a spare blub and colored filters
  (red, green, and a diffused white). The red filter
  helped preserve night vision. This was unnecessary
  in the tunnels because when the flashlight was
  extinguished it was absolutely black; one had no
  night vision as there was no ambient light, just total
  blackness. For this same reason, “starlight-scope”
  25
  A combat engineer attaching
  2½lb M5A1 C4 demolition
  charges to trees in order to
  blast clear a landing zone. The
  clear plastic-covered charges
  are linked by detcord. (1st
  Cavalry Division Museum)
  © Osprey Publishing • www.ospreypublishing.com
  
  light-intensification sights were useless as they required ambient light to
  operate. There was a less-frequently used straight flashlight of similar design,
  the MX-993/U.
  Some use was made of the MX-290/GV lantern. It had a large floodlight
  on its front and a narrow beam dome light on top. It used a BA-200/U battery
  and contained spare blubs for both lights. The dome light was protected by
  a guard and there was a carrying handle. The small aviator’s flashlight and
  other “penlights” were also used.
  A miner’s headlamp was provided with the experimental tunnel-
  exploration kits in 1966. It consisted of a six-volt battery-powered headlamp
  fitted to the front of the field cap (“baseball cap”) and was provided with a
  bite-operated on and off switch. There were problems with this flashlight,
  including a poorly functioning bite switch, the front-heavy cap being pulled
  forward by the headlamp and by rubbing against low ceilings, and the fact
  that the cap’s visor interfered with vision.
  Compasses were used to plot routes through tunnels, and azimuth
  (direction) changes to be telephoned back to the surface. Usually the backup
  man following the lead tunnel rat handled the compass and telephone, but
  sometimes the lead man did. The lensatic compass was a standard-issue, fold-
  open type. The small Waltham wrist compass had a nylon strap, allowing
  hands-free use. Both compasses had glow-in-the-dark compass points and
  needles. Neither was waterproof.
  Measuring tapes were sometimes used, but was difficult to use in the
  confined tunnels. Distances were simply estimated and then adjusted on the
  plot map when additional air vents and entrances were found. The distances
  between turns were usually only 1–10m, making it easy to estimate the
  distance by sight alone.
  The flashlight and lensatic compass, and sometimes pistols, might be
  dummy-corded to the user by “550 cord” (parachute suspension line) or old
  bootlaces. Care had to be taken to prevent dummy cords from snagging on
  obstructions or becoming entangling with body parts. They were a hindrance
  in a hand-to-hand fight, giving the opponent something else to grab on to.
  A vitally important tool for a tunnel rat was his knife. It was used as a
  probe to aid in detecting hidden doors and buried objects, and as a prying
  tool to open trapdoors. And of course, it might be needed as a close-combat
  weapon. The 6.5in. double-edged M6 and M7 knife bayonets for the M14
  Each infantry brigade had 
  an attached scout-dog
  detachment. They were
  invaluable for sniffing out
  tunnel entrances. There 
  was no way a dog could be
  induced to enter a tunnel
  though. (1st Cavalry Division
  Museum)
  26
  © Osprey Publishing • www.ospreypublishing.com
  
  and M16A1 rifles, respectively, were widely used. Air Force survival knives
  with 5in. blades, and M3 and Ka-Bar Mk 2 fighting knifes, were also popular.
  The standard-issue “utility pocketknife” was a Camillus Model 1760 (also
  made by other manufacturers) commonly called the “demo knife.” It was
  rumored to be made of non-ferrous or non-magnetic metal, making it safe for
  demolitions work. This is not true, as the blade was made entirely of stainless
  steel. The TL-29 lineman’s pocketknife saw some use. The M2 cap crimper
  (or “fuse crimper”) was made of non-sparking metal, and besides the crimper
  for attaching blasting caps to time fuse or detcord, it had a screwdriver on one
  handle, a spike-punch for making cap wells in C4, and a fuse/detcord cutter
  as the base of the jaws. Steel probing rods of 1–3ft in length were sometimes
  used, as well as sharpened sticks.
  Entrenching tools were used to uncover tunnel entrances and vents,
  remove camouflage, and widen tunnel entrances. The “tool, entrenching,
  combination, M1951” was a wooden-handled folding e-tool. It could be
  locked in a 90-degree angle position to use as a pick or hoe. From about 1969
  the all-metal alloy, three-way folding e-tool, the “tool, entrenching,
  collapsible, M1967,” was available. It was a “tri-fold” e-tool with a two-
  section handle. Tunnel rats also used machetes, which were very useful for
  clearing camouflage from tunnel entrances. It had an 18in. single-edge blade
  and was carried in a semi-rigid plastic olive-drab sheath.
  Olive-drab nylon rope had a diameter of 7/16in. and was made up of three
  twisted strands. It came in 120ft rolls or 300ft spools. Small three- and four-
  prong grappling hooks, sometimes fabricated by a unit welder, were used.
  These ropes, with or without hooks, were used to drag out equipment and
  bodies. It was seldom that a tunnel rat would tie a rope to himself to allow
  him to be pulled out if wounded or killed, as it restricted movement too
  much. Engineer tape was meant to mark minefields and cleared lanes through
  27
  Weapons are brought to 
  the surface from out of a 
  VC tunnel. There are two
  7.62mm Mosin-Nagant 
  M1944 carbines and two 
  .30-cal. M1918A2 Browning
  Automatic Rifles (BARs), along
  with web gear. (Tom
  Laemlein/Armor Plate Press)
  © Osprey Publishing • www.ospreypublishing.com
  
  them. It was also used to mark tunnel entrances, and was placed around
  booby traps. It was 2in. wide, white in color, and made of non-adhesive tape.
  It was issued in 500ft rolls.
  Kneepads were used by some tunnel rats, but others found them to be
  cumbersome. In addition, they were not always available. Expedient
  kneepads were made by tying field dressings onto the knees by their securing
  ties. Tan leather gloves were valuable, but they too were not always worn as
  they were hot and made it difficult to handle weapons. Similar style, but
  lighter, black leather service gloves were also used. Sometimes the fingertips
  were cut off. This still protected the hands, but allowed the wearer greater
  dexterity when using his hands. In wet, muddy tunnels, gloves became very
  cumbersome, as sticky mud would cling to them. Earplugs were essential
  when weapons were fired, but tunnel rats could not afford to wear them, as
  they had to listen for the slightest sounds. Nevertheless, some did when
  gunplay was expected soon after entering a tunnel. If they were unavailable
  then some tunnel rats simply tore off cigarette filters and plugged them into
  their ears.
  Small XM28 protective masks were widely used from 1967. They
  protected only against CS gas, with a warning to that effect marked on the
  carrying case. While provided with a nylon case, it could be carried in a pants’
  cargo pocket. The M17 protective mask was designed to protect against most
  forms of chemical agents. The earlier M9 gas mask with a canister on the left
  side (some were on the right) saw limited use early in the Vietnam War. These
  “gas masks” did not protect against oxygen-displacing smoke or flumes. That
  required a personal air supply, and such equipment was not available,
  regardless of which is was too heavy and bulky for use by tunnel rats.
  For communications, especially when exploring a large tunnel complex, the
  backup tunnel rat usually carried a TA-1/PT sound-powered field telephone. 
  It required no batteries and was connected to another TA-1/PT or a bulkier,
  heavier TA-312/PT field telephone on the surface. Two-strand WD-1 field wire
  was used, dispensed from a MX-306A/G “donut spool” containing half a mile
  of wire.
  Regardless of all the specialized equipment available, photographic
  evidence shows that most tunnel rats went under the ground equipped only
  C
  TUNNEL-EXPLORATION KIT
  Units assembled tunnel-exploration kits themselves, and no two were alike. There was a scramble
  to collect the necessary equipment when a tunnel system was discovered, and they often had to
  make do with whatever was available. There were some widely used items, especially handguns.
  The most readily available and commonly used were the Colt .45-cal. M1911A1 pistol (1), and the
  Hi-Standard .22-cal. Model HD pistol (2). Above it is the HDM model’s fixed silencer (3). The Ruger
  .22-cal. Mk I pistol (4) was less commonly used than the Hi-Standard. The S&W .38-cal. Special
  Model 10 tunnel-exploration revolver (5) is shown with a removable silencer and aiming light.
  Unmodified Model 10s as used by aviators were also used. The .40-cal. smoothbore Quiet Special
  Purpose Revolver (QSPR) was based on the S&W Model 29 (6). The cartridge fired 15 pellets. Only 
  a small number were available, and they were used from April 1969 to 1971. The lightweight and
  compact XM29 protective mask (7) protected the wearer from tear gas only, was introduced in
  1968. The bulkier M17 protective mask saw much use (8), even after the XM28 was introduced.
  The TA-1/PT sound-powered field telephone (9) was sometimes taken into tunnels to relay route-
  plotting information and what was discovered. It would be connected to another on the surface
  via WD-1 wire dispensed from a ½-mile-long MX-306A/G spool (known as a “donut reel”) (10). The
  lensatic compass (11) was used to determine the tunnel’s changes in direction. The MX-991/U
  right-angle flashlight (12) was the most commonly used flashlight, as it could be shone around
  angles without danger to the tunnel rat. Use was also made of the MX-290/GV six-volt lantern (13).
  28
  © Osprey Publishing • www.ospreypublishing.com
  
  1
  2
  3
  4
  5
  6
  7
  8
  9
  10
  11
  12
  13
  © Osprey Publishing • www.ospreypublishing.com
  
  with a flashlight and .45-cal. automatic, usually barrowed from a grenadier
  or machine gunner, and wearing only boots, trousers, and an undershirt.
  To pump CS through extremely large complexes something more
  powerful than the Mity Mite blower was necessary. In 1966, 33 “large-
  capacity tunnel flushers” were fielded with US, ARVN, and Korean forces.
  These were the Buffalo Turbine Model K, the Mare Generator, and the
  Resojet. They could be sling-loaded under a UH-1 Huey. Besides flooding
  tunnels with CS, they were also used to flush out CS and smoke and supply
  air to tunnel rats. The large-capacity tunnel flushers were operated by
  divisional- and brigade-level chemical detachments.
  An M106 Mity Mite blower
  operated by a chemical
  detachment has been set 
  up to flush smoke and tear 
  gas through a tunnel system.
  (US Army)
  30
  Mity Mite blower
  The M106 Mity Mite agent dispenser was a commercially made sprayer or duster for agricultural pesticides
  marketed by Sears Roebuck and Company. It could spray a CS agent just as easily as pesticides. In fact,
  chemical troops used them to spray mosquito pesticides over ﬁrebases. The backpack-carried device
  consisted of a two-cycle gasoline engine, fuel tank, blower, agent tank, and a 2ft-long disperser hose. It
  weighed 25lb when empty. One quart of fuel would operate the M106 for just over 30 minutes and displace
  450ft3 of air per minute. The agent tank could hold 10lb of powdered CS or 3 gallons of liquid pesticide.
  For use against tunnels, the Mity Mite was set beside a tunnel entrance with additional fuel at the ready.
  The opening would be sealed with a poncho and its edges held down by shoveled dirt. The hose would then
  be inserted through the poncho’s central head opening and sealed with duct tape. Another method suitable
  for small entrances was to use the top half of a 5-gallon oil can with a hole cut in the top. This was jammed
  into the tunnel’s entrance and the dispenser hose inserted. The Mity Mite would then be started and CS
  blown into the tunnel. The air bearing the CS would spread through much of the tunnel system, which is why
  the VC incorporated airlocks and water locks in their tunnels. The duration of the operation depended on the
  tunnel system’s size. The CS would drive out and in some cases asphyxiate inhabitants, as it displaced oxygen.
  Before pumping in CS, colored-smoke grenades were tossed into the entrance and the Mity Mite would
  then force the smoke through the tunnel to reveal most of the entrances, vents, and ﬁring ports. If the system
  was so large that the smoke would not spread throughout its full length, the Mity Mite would be reinstalled 
  at an opening farther along and the process begun again. This allowed the tunnel system’s rough trace to 
  be plotted. White smoke from AN-M8 grenades and M1A1 smoke pots would likewise be pumped in to drive
  out the enemy, as it too could asphyxiate if dense enough.
  Once the tunnel system’s openings were revealed and plotted and then pumped full of CS, the Mity Mite
  would be used to pump in fresh air. This ﬂushed the CS and smoke out of the complex, allowing tunnel rats 
  to enter. Air would continue to be pumped in once the tunnel rats were underground, in order to help them
  breathe. Another method of supplying air was to land a helicopter nearby and run an up to 100ft hose from
  the aircraft’s auxiliary generator.
  The ﬁrst use of the Mity Mite in this role was by the ARVN 8th Infantry Regiment, 5th Infantry Division, in the
  III Corps Tactical Zone in October 1965. This occurred in the Iron Triangle area near Cu Chi 25 miles northwest
  of Saigon. American advisors oversaw the operation, which proved entirely successful, and the techniques
  were subsequently adopted by all Free World forces.
  © Osprey Publishing • www.ospreypublishing.com
  
  CONDITIONS OF SERVICE
  Life in a firebase
  Tunnel rats’ living conditions and daily routine were identical to that of
  normal soldiers. Indeed, tunnel rats were ordinary soldiers for all intents and
  purposes; they were unique only in their willingness to enter places that no
  one else would go. Once they had emerged from their subterranean world,
  they would seamlessly revert back to “normal” status, and enjoyed no special
  privileges. If serving as a combat engineer, a tunnel rat would spend much of
  his time constructing, maintaining, and upgrading firebases (see Fortress 58:
  Vietnam Firebases, 1965–73, Osprey: Oxford, 2007). Rifle companies, too,
  spent time in firebases, as a battalion’s four companies were rotated between
  base security and offensive field operations. These bases were quickly built
  and were considered temporary in most cases. Some were in place for just
  days, others for weeks or months. There were some that were semi-
  permanent, being positioned along main lines of communication and aiding
  in securing population centers.
  Improvements and repairs were ongoing for as long as the base was
  operational. All manner of bunkers had to be built and maintained. Artillery
  and mortar positions, perimeter barbed-wire barriers, Claymore mines, trip
  flares, helicopter landing pads, internal roads, and drainage systems also
  needed to be constructed. Much of the labor was done by infantrymen,
  artillerymen and support personnel, with the engineers assisting. When a base
  was emplaced, engineer units did much of the initial work with powered
  equipment and then moved on to other tasks. Some engineers remained for
  base maintenance, often operating power generators, and were on-call for
  demolitions and tunnel-exploration work.
  Everyone living on the base was involved in perimeter security and base
  defense. Each man was assigned a fighting position if the base was attacked
  and had to know how to find his way there in the dark. Perimeter guard duty
  was rotated, usually with one or two-hour shifts. That involved staying
  awake and alert and peering into the dark tangle of stumps, limbs, barbed
  wire, and picket posts. Typically, NCOs constantly made the rounds, ensuring
  that sentries were awake. Most of the excitement occurred when a trip flare
  was ignited by a marauding animal. Listening posts might be manned at night
  outside the perimeter wire, usually by three men with a telephone or radio.
  In daytime, observation posts might be emplaced farther out. Men also stood
  radio watch, monitoring the command net. If on a line of communications –
  a major highway used by both military convoys and civilian traffic –
  checkpoints would be manned during daylight hours, often in conjunction
  with ARVN, Regional Force, or National Police personnel.
  Besides filling sandbags, building bunkers, and stringing barbed wire, there
  were other work details. These included trash collection, burning trash outside
  the perimeter, burning latrine waste; unloading and storing ammunition,
  rations and supplies delivered by convoy or helicopter; pulling KP (kitchen
  police) duty, water details, and whatever else the first sergeant could think of.
  Seldom was a suitable local water source available. Water would instead be
  trucked in by 1,000-gallon tankers or flown in inside 500-gallon sausage-
  shaped rubber bladders – known colorfully as “elephant turds” – slung under
  CH-47 Chinooks. There was little water available for washing clothes or for
  bathing. There was little in the way of entertainment other than reading, card-
  playing, and letter writing.
  31
  © Osprey Publishing • www.ospreypublishing.com
  
  Chowing down
  In firebases the usual meals eaten were B-rations. These were made up of non-
  perishable and semi-perishable foods including canned, dried, and dehydrated
  products. B-rations were issued where field-mess facilities were available, but
  were not refrigerated. Two or three cooks could prepare meals for 100 men
  in two hours with gasoline field ranges. The food was not unlike A-rations
  D
  LIFE IN A FIREBASE
  While an improvement over life on a combat operation, living in a temporary firebase was 
  no picnic. Food was improved and sleeping quarters were out of the weather, but there were
  endless work details, hours of sentry duty, and occasional mortar and rocket attacks. When 
  a firebase was established it was required that every man sleep under two layers of sandbags 
  by nightfall. Bunkers, especially those that had been occupied for a long time, could be squalid,
  becoming infested with rats, roaches, and other vermin. Victor M200 rat traps and Daisy Red 
  Rider BB guns were provided for rodent control.
  This partly sunken bunker is built of two layers of sandbags and the below-ground walls are
  revetted by pierced steel plate (PSP) airfield mats and U-shaped barbed-wire pickets. This
  particular sandbag wall lacks timber reinforcing to bear the weight of the heavy roof timbers, 
  and the three or more sandbag layers placed atop it. An internal framework of 8in. by 8in. timber
  framing reinforced by 2in. by 10in. diagonal planks might be added later, depending on how 
  long the base remained in place. A heavy caliber near miss, or saturation by prolonged rains 
  could collapse the bunker. Wooden cargo pallets were used as flooring and protected occupants
  from water seepage, but also provided a hiding place for rats. Folding cots, when available,
  required an air mattress (known as a “rubber bitch”), as their tautly stretched nylon beds were
  hard as boards. Camouflaged poncho liners were highly prized, as they provided much warmth.
  The light-nylon fabric had to be taken care of as it was easily damaged.
  Mail call was enthusiastically looked forward to. Every few days a helicopter delivered letters 
  and care packages – candy, cookies, and other treats from home. Care packages were habitually
  shared with squad buddies. Personal gear was stowed in duffle bags. A tunnel-exploration kit
  contained within an aviator’s kit bag, ready to be used at a moment’s notice. Ice, when available,
  was placed in 5-gallon water cans, and beer and soda cans stowed inside. Beer, though, was
  scarce on firebases. An M17 protective mask hangs on the wall.
  Caves were often found among
  tumbled boulders. This area
  has obviously been saturated
  with tear gas. The white
  powder-like substance is bird
  guano. (Tom Laemlein/Armor
  Plate Press)
  32
  © Osprey Publishing • www.ospreypublishing.com
  
  © Osprey Publishing • www.ospreypublishing.com
  
  (fresh food), but all meat and fish was canned or dehydrated. B-rations might
  be supplemented by fresh fruits and vegetables. Cereals, oatmeal, powdered
  eggs, and powdered potatoes were widely used. If prepared properly, the
  powdered eggs in scrambled form were not too bad. Mashed potatoes tended
  to be lumpy. Both canned and dried fruits and vegetables were the same as
  commercially available canned foods. Beverages included coffee, cold tea,
  canned fruit juices, and powdered flavored drinks. For bread, centrally located
  bakeries turned out loafs of bread and B-rations included biscuit, muffin, and
  cornbread mix, as well as pancake and cake mixes.
  Infantrymen and engineers did not spend all their time in remote firebases
  or out in the boonies on operations. Units rotated through brigade and
  division bases, where they provided security or served as air-mobile reaction
  forces. Usually, barracks-type quarters with proper washrooms were available
  along with PXs (post exchanges), clubs, laundries, outdoor movies, and other
  amenities.
  BELIEF AND BELONGING
  Although a tunnel rat had to possess the nerve and courage to squeeze into
  a tiny, pitch-dark hole in the ground, in general their attitudes toward the
  wider war in which they fought were the same as any other soldier. Whether
  volunteers or draftees, tunnel rats held many different views regarding their
  Vietnam tours. It was an abhorrent injustice to some, an inconvenience to
  others, and some simply made the best of it. Regardless of whether one was
  opposed to the war, supported it, or was indifferent, there were few who were
  concerned with the politics surrounding it. If serving in the Army, they knew
  that they had to endure exactly 365 days. Vietnam was initially surreal for
  many, and the shock of entering a strange environment populated with people
  who seemed totally alien was acute, especially considering the fact that most
  draftees were still in their teens. Usually, within a short time, a soldier would
  accept his lot and become comfortable with it. The general attitude was to
  accept one’s fate, stay out of trouble, and do one’s job.
  Many GIs did not think much of the Vietnamese. Even before arriving in
  Vietnam they had heard little good about the ARVN. Many of the people
  The entrance to this tunnel has
  been blasted open by a heavy
  demolition charge, which also
  blew away a great deal of
  vegetation. Engineers are
  dragging out shattered
  reinforcing logs to allow entry.
  (Tom Laemlein/Armor Plate
  Press)
  34
  © Osprey Publishing • www.ospreypublishing.com
  
  seemed unengaged in the war or unsupportive of the government. This 
  was an irritation to many Americans as they were over there risking their
  lives, enduring great discomfort and taking time out from their lives in the
  “real world” to help defend their country. It was no better in the countryside,
  where the villagers were literally on the frontline. They had no faith in 
  the government, which was seldom able to protect them. Their culture
  emphasized loyalty to family and village; beyond that they had little interest.
  They just wanted to be left alone to raise their families, grow their food, 
  and live their lives in peace. Another problem was simply that Vietnamese
  culture was so different and strange to American eyes. Of course, the
  Americans were no less strange to the Vietnamese, especially those living in
  the countryside. Exacerbating the lack of cultural respect were the types of
  people that most Americans were exposed to: pimps, prostitutes, bar girls,
  and drug and porn dealers.
  There were other problems within the ranks, which tended to become
  more serious the farther one got away from the combat troops in the boonies.
  There were drug problems, race issues, and antiwar attitudes. In some cases
  there were leadership problems as the war dragged on, exaggerated by poor
  unit cohesion. It worsened in 1970s as the pace of US troop withdrawal
  increased. That developed into a simple attitude problem, with soldiers asking
  why they should give it their all when the politicians had given up on the war.
  Besides increased drug use from 1969, which was insignificant before, the
  extent of disgruntlement and frustration was demonstrated in “fragging”
  incidents. Fragging was the use of grenades to murder unpopular, abusive,
  inept, or overzealous officers or NCOs. Fragging was typically a series of
  incidents, sometimes conducted in a graduated sequence as warnings – a
  smoke grenade might be tossed into an officer’s tent, then a tear gas grenade,
  a frag grenade without the pin pulled, and finally a frag grenade with pin
  pulled. The targeted individual usually got the point before the process ran
  its full course. Fragging was not necessarily limited to grenades. Disgruntled
  men often took the opportunity to shoot their own leaders during the
  confusion of combat, where it would be assumed that the victim had been
  35
  A tunnel rat peers into a tunnel
  entrance. A bayonet scabbard 
  is fastened to his right calf by 
  a web strap. Such straps also
  served to secure baggy pants 
  in order to reduce snagging.
  (25th Infantry Division Museum)
  © Osprey Publishing • www.ospreypublishing.com
  
  killed by the enemy. Booby traps were also sometimes used. There are no
  accurate and complete figures for fragging incidents, and there are a great
  many officer and NCO deaths of uncertain circumstances. Between 1969 and
  1971 there were over 700 fragging incidents reported, though not all resulting
  in death.
  Every war is stressful, taking its mental, moral, and physical toll on
  soldiers, but the Vietnam War was exceedingly so, with problems not seen to
  anywhere near as great an extent in previous wars. For the tunnel rat the
  rigors of combat and the privations of military life were exacerbated by the
  unique perils of the tunnel they explored.
  Into the black echo
  A question often asked is why a tunnel rat would volunteer to crawl into a tiny
  hole, probably occupied by a desperate enemy, and filled with CS, booby traps,
  vermin, and other perils? They could expect to suffer from claustrophobia,
  panic, oxygen deprivation, and the possibility of being stuck or otherwise
  trapped underground. They called it the “black echo,” which aptly described
  the environment. They described their dangerous job as “running the hole.”
  E
  SEARCHING FOR TUNNEL ENTRANCES AND AIR VENTS
  In the Cu Chi area it was a given that tunnels snaked beneath a village. The challenge was to find
  them, as the VC had become adept at placing entrances and air vents in the most unlikely places,
  and were skilled at camouflaging them. Infantrymen conducted an initial sweep though a village,
  mainly on the lookout for overt activity such as weapons and munitions that weren’t hidden
  underground quickly enough and stay-behind VC, which were usually snipers. They also observed
  how the villagers behaved. They probed under piles of wood and manure, heaps of discarded
  materials, large earthenware pots, and clumps of brush. Engineers might be flown in to a nearby
  landing zone to conduct a closer examination. Since searches might continue in the village for
  some time, an adjacent LZ would be cleared if none were available. Supplies and equipment
  would be flown in and any casualties and VC suspects evacuated.
  Here, combat engineers bring in a chainsaw and demolitions materials to clear a one-ship LZ
  beside a village. The Remington Super 75 chainsaw shown here was one of several models used
  to fell trees for an LZ and slash down brush and bamboo when searching for tunnel entrances.
  The 1-gallon fuel can held by the central figure holds a 1:16 fuel mixture, with 1 pint of lubricating
  oil to 2 gallons of gasoline. This same mixture was used in the Mity Mite blower. Slung on the rear
  man’s rucksack frame is an M183 demolition-charge assembly (satchel charge) holding 16 M112
  1.1lb C4 charges.
  36
  ABOVE
  A VC prisoner is taken inside 
  a cave by 1st Cavalry Division
  troopers. Caves like this were
  found in granite mountains
  such as Nui Ba Den and Nui Ba
  Ra in the III Corps Tactical Zone
  and Nui Giai and the Seven
  Sisters Mountains in the IV
  Corps Tactical Zone. Note 
  the M16A1 rifle’s 30-round
  magazine, which was extremely
  rare in Vietnam. (Tom
  Laemlein/Armor Plate Press)
  ABOVE RIGHT
  “Pull me out!” There is no
  question that this 1st Cavalry
  Division tunnel rat has run into
  trouble and needs assistance 
  to get out of the cave, now.
  (Tom Laemlein/Armor Plate
  Press)
  © Osprey Publishing • www.ospreypublishing.com
  
  © Osprey Publishing • www.ospreypublishing.com
  
  Few tunnel rats could even answer that
  question, at least not fully. The reasons were as
  complex and varied as any man’s motivations for
  volunteering for any dangerous undertaking.
  Many tunnel rats did the job simply because it
  needed to be done. Others did it because it was
  indeed a dangerous and challenging task. They
  wanted to prove themselves, earn respect or honor,
  or experience the adrenaline rush. Others went
  into the ground to meet the enemy face-to-face, to
  penetrate into the unknown and crawl into the
  enemy’s domain; to play in the enemy’s backyard
  so to speak. Some did it as a lark, thinking it would
  be a short-lived deal. The reasons were varied and
  could have been a combination of many things;
  there were no simple explanations.
  Most tunnel rats were volunteers and could
  “unvolunteer” at any time. The continued stress
  and pressure of the job, or even some particularly
  dangerous incident, could cause one to have
  second thoughts. Anyone doing so would seldom
  be criticized, especially since few officers had ever
  ventured down a hole. Most units prohibited
  officers from entering tunnels. Some tunnel rats,
  however, did not step out. They feared ridicule or
  could not admit to themselves they did not have
  what it takes. Sooner or later they were forced to
  give it up.
  In most cases there was no formal process for
  volunteering for the duty. Most said that anyone
  over 5ft 6in. need not apply. Nor were there any
  training courses within units. Many tunnel rats got their start by simply
  stepping forward when the platoon leader or company commander asked for
  volunteers to enter and explore a discovered hole. Often there was no time
  to wait for engineer and chemical support. They needed to know immediately
  if there was anyone inside or anything of value to the enemy that could be
  pulled out or destroyed. There were instances in which unprepared men were
  ordered to check out a tunnel. This seldom went well. If the tunnel proved 
  to be part of a large complex, engineer support might be called in and the 
  area secured. In the meantime, the infantry would continue to reconnoiter
  the area in search of additional entrances, vents, caches, fighting positions,
  and contraband.
  Some engineer and chemical units conducted a little informal orientation
  training, mainly on how to operate the Mity Mite, and were provided
  diagrams of tunnel complexes for study. For the most part, on-the-job
  training was undertaken on actual operations. New men served first in the
  support party above ground, then followed a lead tunnel rat, before finally
  taking on the lead position themselves. There were support-party men who
  never had any intension of going into the “black echo.”
  There is no question that tunnel rats had no shortage of guts. They were
  awarded with promotions and valor awards, the most common being the
  Army Commendation Medal for Valor and the Bronze Star for Valor.
  A simple one-man shelter. Such
  a site might have a tunnel
  entrance concealed within it.
  Loose leaves were commonly
  spread on slit-trench floors,
  making them less noticeable
  from the air. (Tom
  Laemlein/Armor Plate Press)
  38
  © Osprey Publishing • www.ospreypublishing.com
  
  ON CAMPAIGN
  Tunnel rat “units”
  Few soldiers had even heard of tunnel rats until arriving in Vietnam. Even
  then they were seldom aware of them until possibly seeing them wiggle half-
  naked into a tiny hole with only a pistol and flashlight. There was no such
  thing as established tunnel rat units. Tunnel rat teams, sometimes more
  formally called “tunnel exploration” or “tunnel destruction” teams, were
  ad-hoc teams assembled from experienced personnel performing their
  normal duties. They might have been combat engineers, infantrymen, cavalry
  scouts (if an armored cavalry unit), and even from chemical detachments.
  Some units designated personnel for the job when needed. Others had small
  standing teams in the headquarters that would be augmented by other
  experienced personnel as needed. Inexperienced volunteers would be
  employed for support.
  There was no “standard” organization or strength for tunnel teams. There
  might be one to four tunnel rats venturing alone underground or
  accompanied by a backup man (depending on the number of entrances
  discovered), a few men on the surface at each entrance, and personnel to
  operate Mity Mite blowers. The surface-support party aided with quickly
  extracting tunnel rats, passing down necessary equipment, preparing
  demolition charges, maintaining telephone or verbal contact with the tunnel
  rat, and plotting the tunnel’s course with the information relayed back to
  them. The infantry provided security at each entrance as well as additional
  security throughout the village or area. The outer perimeter was also secured
  by infantry to guard against external counterattack.
  Most units used three-man teams, consisting of a supervisor and two
  tunnel explorers. Some used a five-man team, which was the same as a three-
  man but with two general-support members, who remained on the surface.
  The allocation of teams varied between units. Four units heavily involved in
  tunnel exploration and destruction in the III Corps Tactical Zone in late 1966
  recommended the issue of tunnel-exploration kits throughout the corps. This
  39
  Tunnel rats bring up an 82mm
  PM37 mortar. Such heavy and
  bulky weapons were difficult 
  to haul out of the cramped
  tunnels. (25th Infantry Division
  Museum)
  © Osprey Publishing • www.ospreypublishing.com
  
  was not necessarily an indicator of the number of teams fielded, but it gives
  an idea of how teams were allocated (see sidebar).
  The 1st Infantry Division had recommended one tunnel exploration kit
  per brigade and had in practice spread tunnel rat teams throughout infantry
  battalions. It was soon found that their employment and level of skill was
  wanting. The tunnel-exploration and tunnel-destruction mission was given to
  the division’s 1st Engineer Battalion in 1967. Their demolition expertise
  proved essential.
  As many tunnel rats were from specialized engineer and chemical units,
  the activities and makeup of these units deserves some attention.
  Combat engineer battalions
  A roughly 950-man combat engineer battalion was assigned to each of the
  seven Army divisions in Vietnam. There were also 13 non-divisional combat
  engineer battalions plus combat engineer companies assigned to separate
  brigades. In Vietnam, combat engineers were capable of constructing simple
  facilities, repairing roads and bridges, repairing airfields, etc, but most of
  their efforts were spent on building firebases, airstrips, helipads, installing
  and repairing barriers around bases, maintaining and repairing roads,
  clearing helicopter landing zones, and clearing roads of mines. Engineers
  might also have been attached to rifle companies to handle demolitions,
  mainly for blasting bunkers, tunnels, and supply caches. They also created
  small helicopter landing zones to lift out troops, deliver supplies, and medevac
  wounded men. This was accomplished through the use of explosives,
  chainsaws, and machetes. Another job was to assist with the extraction of
  food, munitions, and other material discovered in enemy caches (which were
  often hidden in tunnels).
  Chemical detachments
  Divisions and separate brigades were authorized a small chemical
  detachment. In a conventional environment the detachment operated with
  Even though part of the
  camouflage has been removed,
  this tunnel or shelter entrance
  demonstrates just how difficult
  they could be to locate in
  dense vegetation. (Tom
  Laemlein/Armor Plate Press)
  40
  Tunnel-exploration kit
  allocation
  1st Infantry Division
  Two per chemical
  detachment
  One per brigade
  One per division support
  command
  25th Infantry Division
  Two per riﬂe platoon
  Two per battalion
  reconnaissance platoon
  One per riﬂe squad in cavalry
  squadron
  1st Cavalry Division (Airmobile)
  Three per riﬂe company
  Three per engineer company
  173rd Airborne Brigade
  (Separate)
  One per riﬂe company
  One per engineer company
  © Osprey Publishing • www.ospreypublishing.com
  
  the division command post, advising the staff on chemical warfare and smoke
  operations, decontamination requirements, and enemy chemical-warfare
  capabilities. They also coordinated chemical, biological, and radiological
  reconnaissance and surveys among the division’s units. In Vietnam the five-
  man detachment had little to do other than advise on the employment of tear
  gas. Often the detachment was expanded to operate Mity Mite blowers and
  assist with the employment of tear gas against tunnels as well as for area
  denial. The latter included dropping bulk CS powder from helicopters,
  spraying both CS and defoliants from helicopters, and firing CS artillery
  rounds. The detachment did not actually perform the CS delivery, but
  planned and coordinated its use. Area denial using CS included saturating
  known enemy base areas, caches, infiltration trails, and abandoned US
  firebases (to hamper VC scrounging). Detachments operating Mity Mites and
  other blower systems might include tunnel rats. How these detachments were
  used and augmented varied much between divisions and brigades. By 1966
  most were augmented by a standing tunnel rat team or at least a Mity Mite
  team. A team operating a Mity Mite was typically made up of the following:
  One team leader (an officer or NCO)
  One Mity Mite operator (who carried the blower)
  One assistant operator (who carried 2 gallons of gasoline, 1 quart of oil,
  a tool kit, and two ponchos)
  Three munitions bearers (who each carried three M1A1 smoke-pots and
  five M18 colored-smoke grenades)
  EXPERIENCE IN BATTLE
  The experiences of the tunnel rat varied greatly depending on unit techniques,
  the terrain, and how the enemy operated, as well as the period in which he
  served in Vietnam. There were no typical operations. Each had its own unique
  aspects and dangers.
  Tunnel rats of the 168th
  Engineer Battalion prepare 
  to enter a tunnel in the Iron
  Triangle. Its camouflage and
  surrounding foliage have been
  blasted away. An RL-39A field
  telephone wire reel holding
  500ft or wire can be seen to 
  the right. The spiral cord leads
  to a TA-1/PT sound-powered
  telephone. The shoulder
  insignia is of the 18th Engineer
  Brigade. (Tom Laemlein/Armor
  Plate Press)
  41
  © Osprey Publishing • www.ospreypublishing.com
  
  Tunnel systems might be nothing more than a few feet in length, quite
  often less than 70ft. Tunnel rats were also often called upon simply to check
  simple bunkers. This was not because bunker searches were difficult, but
  because tunnel rats were better prepared to deal with booby traps. Large,
  sprawling, multi-level tunnel complexes were rare.
  A “cherry” tunnel rat
  A newly volunteered tunnel rat, if at all possible, would be introduced to the
  underground world by searching individual bunkers and very small
  complexes. Of course, when large complexes were discovered he might be
  forced to take on more challenging searches.
  A 25th Infantry Division tunnel rat, assigned to Company D, 2nd
  Battalion, 27th Infantry, was initiated into his subterranean vocation by
  searching small bunkers found in an enemy base camp. The entrances were
  hidden in clumps of brush. The 2ft-diameter shafts were sunk 5–6ft into the
  ground. Some 2ft above the bottom (the lower part served as a water and
  grenade sump) was a horizontal shaft running for several feet before making
  a sharp turn; it then ran a few feet into a chamber large enough to house one
  or two men. The tunnel rat was lowered by his arms into the shaft and a
  flashlight and pistol were passed down as he waited for his eyes to adjust and
  listened for sounds. Even in the entrance shaft it was noticeably cooler. As
  tunnel rats seldom expected to find such nests occupied, they rarely first
  dropped in a grenade. That said, any sound or sign of occupation would
  warrant one being tossed in. Using extreme caution, the tunnel rat would aim
  his flashlight around the angle of the horizontal tunnel, ready to pull his arm
  back at a instant’s notice. The smelly sleeping chamber would be quickly
  searched for weapons, ammunition, equipment, and documents.
  After searching several such nests, the novice tunnel rat gained more
  confidence, sometimes leading to overconfidence. Lowered into another shaft,
  our tunnel rat peered into the tunnel and in the flashlight beam saw a leg. He
  immediately fired his .45-cal., resulting in a damaged eardrum. Backing out
  and checking again, he determined that the leg had not moved. With extreme
  A crisscrossed log-constructed
  bunker. The tiny entrance was
  typical. This made it difficult 
  for Americans to enter and
  complicated efforts to avoid 
  or detect booby traps. (Tom
  Laemlein/Armor Plate Press)
  42
  © Osprey Publishing • www.ospreypublishing.com
  
  caution he checked the VC and found that he was
  dead from previous wounds. It appeared that he
  had crawled into the hole and bled to death. Enemy
  dead were typically left in tunnels and bunkers.
  Most tunnel systems were excavated by Local
  Force VC. Main Force VC and the NVA did not
  build tunnel systems; tunnels were long-term
  projects and these groups were mobile combat
  forces. They used more conventional defensive
  positions and bunkers. However, tunnels were the
  only way in which Local Force VC could survive.
  They had to have facilities, storage sites, and
  places to hide. One cannot operate and hide in the
  jungle in one area over prolonged periods of
  months and even years without being found. Going underground provided an
  ideal hiding place. They were ideal in the tactical sense, but not for comfort
  or well being. Life underground was miserable and dangerous, but there were
  few alternatives. The Local Force’s role was to defend and control the villages.
  They relied on the sympathetic or intimidated villagers for intelligence, food,
  43
  Infantrymen light a book of
  matches to drop down a tunnel
  entrance shaft to determine 
  its depth. The M17 protective
  mask case is seen on the left
  hip of the rightmost man, its
  normal position of wear. 
  The center man also has a
  protective mask case. The 
  small pocket was for
  accessories. (1st Cavalry
  Division Museum)
  A 25th Infantry Division tunnel
  rat peers around a bend in a
  cave. He is armed with a .38-cal.
  Special S&W Model 10 revolver
  and holds an early version of
  the MX-991/U right-angle
  flashlight without the guards
  protecting the switch. (Tom
  Laemlein/Armor Plate Press)
  © Osprey Publishing • www.ospreypublishing.com
  
  and labor. It would be trusted villagers who concealed the entrances when the
  VC ducked into their tunnels. Fear of retaliation kept most villagers quiet.
  Once they had concealed the entrance, a procedure they practiced, they would
  continue on with their daily routine, hoping to appear innocent when Free
  World troops arrived. They might be tending a garden, carrying firewood
  down a path, or feeding chickens.
  A “routine” day
  Tunnels invariably had at least two entrances, to allow escape if one was
  discovered, plus two or three vents. A great deal of caution had to be used
  when tunnel rats emerged from an opening other than the one they entered
  F
  UNCOVERING AND ENTERING A TUNNEL
  Only one tunnel entrance had to be found initially. This would be carefully uncovered and
  checked for booby traps. Sometimes a satchel charge would simply be detonated at the entrance
  to blast away camouflage, blow open any covering material, detonate booby traps, and kill any
  waiting ambusher. Once exposed, frag and CS grenades might be thrown in, just to make sure.
  The entrance would then be sealed with a poncho, an M106 Mity Mite blower hose inserted,
  M1A1 white smoke pots emplaced, and the tunnel flooded with the oxygen-displacing smoke.
  Besides flushing out the VC, the smoke seeped out of other entrances, air vents, and firing ports.
  Infantrymen would be placed throughout the area to report any smoke seepage. Additional
  troops were sent to cover each discovered entrance in order to guard against a breakout. Tear gas
  flooding through tunnels could force the desperate VC to emerge into withering fire. An M1A1
  smoke pot weighed 12lb and burned grayish-white smoke for five to eight minutes after a ten-
  second delay. Colored-smoke grenades, with less-dense smoke, were used in the same manner.
  Before a tunnel rat entered the tunnel, the Mity Mite was used to flush out the smoke and tear
  gas. Besides M183 satchel charges containing 16 1.1lb M112 C4 blocks, entire 46lb cases of C4
  with 30 M112 charges were dragged into tunnels, emplaced at key points, linked by detonating
  cord, and detonated, in order to collapse them. Troops cleared the area for this event. Besides the
  obvious danger of collapsing tunnels, hidden ammunition stores could be sympathetically
  detonated, with impressive results.
  44
  Troopers of the 1st Cavalry
  Division cautiously inspect a
  Vietnamese hooch northeast of
  Saigon. Even though villagers
  are present, there are fearful of
  booby traps and ambushes.
  (Tom Laemlein/Armor Plate
  Press)
  © Osprey Publishing • www.ospreypublishing.com
  
  © Osprey Publishing • www.ospreypublishing.com
  
  through fear of being shot by friendlies. The entrances and vents were often
  ingeniously hidden. Small tunnels would also be found on the outskirts of
  villages in such unlikely areas as cemeteries, cultivated fields, and along
  riverbanks with underwater entrances.
  A typical search-and-clear operation entailed a village being cordoned off,
  which involved it being surrounded with troops posted to prevent anyone
  entering or leaving the area. There also had to be a reaction force available
  in the event of a breakout or an external counterattack. The smaller tunnels
  found in most villages did not house elaborate facilities, but served only to
  hide weapons, equipment, food, and the VC themselves.
  Villagers would be questioned and a scout dog would make the rounds,
  as well as infantrymen making visual searches. Sometimes a previously
  captured VC or a willing informer was brought in to identify entrances. When
  these small tunnels were discovered, infantrymen would sometimes volunteer
  to check them out. They may or may not have had previous experience. Some
  units put together ad hoc tunnel teams with minimal equipment. If the area
  appeared to be ripe with tunnels, caches, and bunkers, engineer tunnel rats
  would be called in.
  Either way, any discovered entrances and vents were marked and the
  camouflage removed, whilst always on the lookout for ingenious booby
  traps. An interpreter or Kit Carson Scout1 would shout into the tunnel for
  the occupants to surrender or be grenaded or buried alive. After this, any
  VC would simply come out with their hands up, sometimes even with
  sheepish grins. They would be “encouraged” to reveal other tunnels and
  hidden sites.
  A grinning VC is ordered out of
  tunnel entrance. This entrance
  is in an unusually exposed
  place, with little concealment.
  It required some effort to place
  them in less obvious locations.
  (1st Cavalry Division Museum)
  46
  1 These were defected VC who were validated and accepted as Hoi Chanhs (ralliers) under the
  Chieu Hoi (open arms) program implemented by the RVN Government in 1963. They were
  attached to US units and were invaluable as scouts, for locating booby traps and tunnels,
  and communicating with civilians.
  © Osprey Publishing • www.ospreypublishing.com
  
  Even if anyone came out of the tunnel to surrender, the tunnel rat’s job
  was not done. The unimposing entrance might lead to 30ft of tunnel or a
  massive multi-level complex stretching for hundreds of feet. Even if it was a
  small tunnel, it had to be searched for anything of value to the enemy. The
  tunnel was initially explored to determine its extent. If it went beyond 300ft,
  further exploration was often called off. There simply was not the time or
  manpower. If a tunnel complex was that large it was usually blasted closed.
  If no VC came out of the tunnel, and even after someone did, the entry
  shaft would be grenaded or a small demolition charge would be dropped in.
  This not only neutralized any waiting enemy, but detonated or disabled
  booby traps. If it was suspected that the complex was large enough for the
  effort, a Mity Mite team would arrive. They would drop in white smoke pots
  or colored-smoke grenades, seal the entrance to prevent the escape of air and
  smoke, and begin forcing in air to spread the smoke, thereby identifying other
  entrances and vents. Once this was accomplished, CS grenades would be
  dropped in and as the smoke was flushed the CS seeped through the tunnels.
  These processes could take up to an hour. Before tunnel rats could enter, the
  blowers were operated for another hour, pumping in fresh air to flush out
  the remaining smoke and CS. Fresh air might continue to be blown in to aid
  tunnel rats once they were inside, but more than not often they requested
  that the blowers be turned off so they could hear the slightest sounds.
  The tunnel rat knew that the larger the complex, the more dangerous it
  was in regards to confronting the enemy and finding booby traps. Crawling
  into the tunnel, the lead tunnel rat would let his eyes adjust and listen. It
  would only take one or two angle changes to be in total darkness. Near the
  entrance with some indirect light available, and he would search for booby
  traps. This would most likely be in the form of tripwires, but booby traps
  could come in the form of pressure-activated mines, a detonator under a
  board or log, or a completely concealed punji stake pit.
  A Vietnamese interpreter
  questions villagers in hopes of
  finding out information on the
  enemy. The location of tunnel
  entrances was highly valuable
  information. (1st Cavalry
  Division Museum)
  47
  © Osprey Publishing • www.ospreypublishing.com
  
  A knife or probe was helpful at this point, but having just entered, our
  tunnel rat held a pistol at the ready and a flashlight in his other hand. He
  listened. Even though he was wearing an XM28 mask, he could smell the
  lingering zinc smell of the smoke and burnt CS, and could feel its burning
  itch on his bare arms. He knew it would progressively worsen. The mask
  restricted his field of vision, with the flashlight creating a glare. It was also
  hot, making his face sweat, and was just plain uncomfortable.
  He eased forward, moving one hand and one knee at a time. Besides the
  smoke and CS, he smelled intense mustiness and human waste. It was cool,
  dry, and dusty. Scanning the floor, walls, and ceiling, he was looking for any
  signs of booby traps or concealed trapdoors. A knife was on his belt or in his
  cargo pocket. With close examination, trapdoors might be found by detecting
  seams, a change of texture, or small piles of
  crumbled dirt and dust. The latter might be found
  below vents too. He could also feel moving air
  near a vent, as the blower was not forcing air
  down the tunnel. Even if it had been, he might
  notice warmer air coming into the tunnel at the
  vent.
  Behind him was his backup man, another
  tunnel rat, and a “cherry” just as he had been only
  a couple of months before. The backup man held
  a compass and a TA-1/PT sound-powered
  telephone. Each time they came to an angle
  change he would give the azimuth (direction)
  change in degrees to the surface party, along with
  This hooch was burned to the
  ground when a hidden bunker
  was discovered inside. It
  appears to have been blasted
  open by a satchel charge. (Tom
  Laemlein/Armor Plate Press)
  48
  A cross-section of a tree (its
  underside is shown here) was
  attached to a hinged frame to
  conceal a tunnel entrance,
  making it appear to be a tree
  stump. (Tom Laemlein/Armor
  Plate Press)
  © Osprey Publishing • www.ospreypublishing.com
  
  49
  the estimated distance back to the last angle change. They plotted this on a
  paper map. It was not precisely accurate, but close enough to get a general
  idea of the tunnel’s course and layout. They also relayed back any features
  such as side rooms and what they contained, air and water locks, other
  entrance shafts, vents, and anything of interest. If an entrance could be found
  on the surface then it would be opened to allow in fresh air and to provide a
  closer escape route for the tunnel rats. The surface party often moved to this
  new exit and dropped the phone line in there. This gave the backup man less
  wire to drag behind him. After even a hundred feet it was difficult to drag,
  and it became caught on walls and obstructions.
  Sounds made by the enemy often led to a halt and a period of prolonged
  listening. If deep in the complex, it was not considered cowardly for the team
  to back out, fast. There was nothing to be gained in a blinding, ear-shattering
  shootout at a few yards’ range. It was not worth it to kill one or two of the
  enemy, or to press on and try to explore more of a tunnel. More importantly,
  it was not worth getting killed for, which was virtually certain with fire
  directed down a narrow tunnel.
  It was exhausting work demanding the use of all one’s senses, and the
  mental and physical strain was great. The two tunnel rats might periodically
  exchange positions if they could squeeze past one another.
  Detecting a booby trap was a tense moment. It had to be examined
  closely to determine what it was and how it was triggered. There was always
  the possibly that it might have two different types of triggers, causing it to
  detonate when one of them was activated. Grenade arming pins were carried
  to neutralize booby-trapped grenades. A wire-cutter, side-cutting pliers, or
  M2 cap crimper could be used to cut tripwires. When bypassing a
  neutralized booby trap, extra caution had to be used, as it may have been a
  diversion for a second one just a few feet down the tunnel. More often,
  especially if deep within the complex, it was advisable to simply leave a
  An American-made M26 frag
  grenade, or “lemon grenade,”
  rigged as a booby trap. It is
  secured to the stake by trip
  wire. A safety pin has been
  inserted into the grenade in
  order to disarm it. (Tom
  Laemlein/Armor Plate Press)
  © Osprey Publishing • www.ospreypublishing.com
  
  booby trap alone and withdraw. It was rare if ever for tunnel rats to install
  their own booby traps. It was too time consuming, they were dangerous to
  install, and they achieved little.
  After two angle changes, each leg being some 15ft long, our two tunnel
  rats came to a side room. The opening to the right was easily made out as a
  black patch in the wall. It was reported to the surface. Approaching with
  G
  BOOBY TRAP IN A TUNNEL
  The hazards of exploring a tunnel system were numerous, even before taking account of the
  enemy. There was vermin, dangerous animals and bugs, oxygen degradation, smoke and fumes,
  residual tear gas, the danger of becoming trapped, and more. The VC sometimes emplaced booby
  traps, but this was not as widespread as is generally assumed. There was the problem of long-
  term storage of mechanical and explosive devices in a dusty or wet environment, the amount 
  of time necessary to emplace such traps, and the danger of one’s own people triggering it.
  The simplest and most rapidly emplaced booby traps incorporated hand grenades, which were
  readily available. These were usually tripwire-activated. Once such a grenade was activated by
  pulling the arming pin via a tripwire, after which the arming lever flew off (clearance had to be
  provided to allow for the lever’s arc), the grenade detonated after its normal delay. This was 
  3.2–4.2 seconds for Soviet/Chinese grenades, and 4–5 seconds for American grenades. This 
  delay time was insufficient to allow a tunnel rat to back out, no matter how alert and quick he 
  was; the fragments and blast over-pressure would funnel down the confined tunnel further than
  he could move in that short time. Even if he were able to take cover around a turn or sharp angle,
  the over-pressure would wound or completely disable him. Of course, such booby traps were not
  emplaced near such cover anyway. Trip wires could be run at any height and angle. Fortunately,
  trip wires were relatively easy to detect in a flashlight’s glow. The tunnel rat shown here is using
  an Air Force survival knife as a probe and is armed with a .45-cal.
  Grenades could be placed in a small hole, usually inside a can, with the pin already removed and
  the can holding down the arming lever. When the wire was pulled it yanked the grenade out of
  the can, allowing the lever to fly off. This particular grenade is inserted inside a downward-angled
  can and held in place by a piece of wood, to which the wire is attached. The grenade would slide
  out when the wire was tugged. Tunnel rats carried grenade-arming pins to deactivate such booby
  traps. Further down the tunnel is a punji-stake trap concealed by a mud-covered woven mat. The
  bamboo stakes, often smeared with excrement to cause infection, could seriously disable a tunnel
  rat and he would then be difficult to extract from the tunnel.
  Troops inspect a village water
  well for a hidden tunnel
  entrance. In the background is
  an M48A3 Patton tank. (Tom
  Laemlein/Armor Plate Press)
  50
  © Osprey Publishing • www.ospreypublishing.com
  
  © Osprey Publishing • www.ospreypublishing.com
  
  caution, before moving up to the opening, the surrounding areas were
  searched for booby traps. With even more caution, the lead man crept up to
  the opening, quickly shinned the light in and jerked it back immediately. With
  no reaction from within, he quickly peeked in with the light. After waiting for
  some seconds he looked in again, slowly sweeping the light through the room,
  and seeing dark shapes. Taking more time, he worked the light through the
  chamber, checking the shapes and probing into corners. He swept the ceiling
  too, noting that it was braced by thick lengths of bamboo.
  Anything could be turned up. The author was with a 1st Cavalry Division
  battalion as a liaison NCO. One of its companies found 50 pairs of A-cup
  bras, and a several-days-old human left arm in one tunnel. No one even tried
  to speculate. A few days later another company in the battalion found a
  bunker with cardboard boxes of brightly colored bikini bottoms. The
  battalion CO on the radio couldn’t stop laughing and asked the company
  CO if there was right arm in the bunker. The irony was lost on the captain.
  Within the side room our tunnel rats found a Chinese-made 57mm
  recoilless rifle and four crates of ammunition, with four rounds in each. There
  were also several sacks of rice and a full rucksack. This was reported and
  they awaited word on what to do. Only the lead man had entered the 4ft by
  6ft room. The backup man crept ahead to the next bend, checked it out, and
  waited with his pistol ready. After a wait that seemed to last forever, the
  Infantrymen and an M113A1
  APC commander aid in pulling
  up the wheeled mounting 
  of a 7.62mm SG43 machine
  gun from out of a bunker. 
  A slit trench serves as a 
  bunker entrance. (Tom
  Laemlein/Armor Plate Press)
  © Osprey Publishing • www.ospreypublishing.com
  
  telephone told them to bring out the “reckless rifle” (they suspected the CO
  wanted it as a unit war trophy), the rucksack, which might contain
  intelligence documents, and the rice. This would support a program in which
  captured rice was given to RVN Government-controlled villages. There were
  four 50kg (110lb) sacks. It would be a struggle to get the bulky and heavy
  bags out, so the tunnel rats reported that there
  were only two bags. The ammunition was not
  touched, as it might have been booby-trapped. As
  the lead man checked the rice, rucksack, and
  recoilless rifle for booby traps, a support man, a
  wannabe tunnel rat, came down the tunnel with
  two lengths of 120ft nylon rope tied together 
  to make a continuous loop. The rucksack was 
  tied to the loop first, because of its potential
  intelligence value. It was pulled out easily, with the
  support man working the looped rope around his
  leg. This way the next item could be tied on and
  pulled out without having to bring a rope back
  down the tunnel. The rice bags were next, and
  proved to be difficult to drag around the tunnel’s
  corners. Lastly came the recoilless rifle, which
  proved to be extremely difficult to remove, with
  its many projections digging into the dirt. It had to
  be worked every inch of the way.
  Owing to the time spent dragging the material
  out of the tunnel, it was decided to emplace
  demolition charges to collapse it, destroying the
  ammunition and the remaining rice (the latter of
  which was unknown to the CO). Two 18lb M183
  satchel charges were brought down the tunnel.
  American-produced sacks 
  of grain are brought up from 
  a tunnel by 11th Armored
  Cavalry Regiment troopers.
  They would be turned over to
  RVN Government-controlled
  villages. Such items were often
  stolen by stevedores and truck
  drivers or sold or traded by
  corrupt government officials.
  (Tom Laemlein/Armor Plate
  Press)
  53
  A tunnel rat brings canned
  rations out of an underground
  supply cache. (25th Infantry
  Division Museum)
  © Osprey Publishing • www.ospreypublishing.com
  
  The surface party had precut the length of detcord from the entrance to the
  side room based on the measurements given by the tunnel rats. One satchel
  charge was set in the side room with the 57mm ammunition and the other
  midway between the room and the entrance. Lengths of detcord from the
  satchel charges were tied onto the mainline detcord with girth hitches with an
  extra turn. The surface party prepared a third charge about 10ft inside the
  BELOW
  Detonating cord is passed
  down to 173rd Airborne
  Brigade tunnel rats as they
  prepare to demolish a tunnel
  complex. While filled with 
  a sensitive high-velocity
  explosive, plastic covered
  detcord was safe to handle 
  and was even used as a
  clothesline in a pinch. (Tom
  Laemlein/Armor Plate Press)
  BELOW RIGHT
  Prepared satchel charges filled
  with 2½lb M5A1 charges are
  passed down to 173rd Airborne
  Brigade tunnel rats. These
  would be placed at intervals
  throughout the tunnel’s length.
  The yellow cords are time-delay
  fuse. Behind the man’s head in
  the tunnel can be seen field-
  telephone lines. These would
  be pulled out prior to
  demolishing the complex. (Tom
  Laemlein/Armor Plate Press)
  RIGHT
  A view from within a tunnel. 
  A 173rd Airborne Brigade
  tunnel rat lowers a satchel
  charge to a comrade. (Tom
  Laemlein/Armor Plate Press)
  54
  © Osprey Publishing • www.ospreypublishing.com
  
  55
  entrance and fitted an electric detonator. An electrical firing wire was run out
  100ft to a ditch. The rifle platoon leader securing the site was briefed about
  where the tunnel was and he moved his troops back.
  The lead tunnel rat was the last man out, and he double-checked the ties
  in the detcord. Everyone was ordered to take cover. The 10-cap blasting
  machine was attached to the firing wire, and the area surveyed to ensure that
  all was clear. The traditional, “Fire in the hole,” was shouted three times.
  The team leader then twisted the handle on the “hellbox” and the three
  satchel charges detonated simultaneously with a dull trump. It was felt
  through the ground and a large clould of reddish dust was blown from the
  entrance. Dust also puffed from vents and a second entrance farther away.
  There were whoops of excitement from the troops.
  The platoon leader immediately sent a squad to the second entrance and
  three frag grenades were dropped in once the shattered trapdoor had been
  completely removed. A CS grenade was tossed in for good measure. As time
  was short and they had been ordered to search a small base camp discovered
  a kilometer away, they could not leave this entrance intact.
  They prepared another satchel charge, this one with two dual-initiated,
  30-second time fuses with a blasting cap on the ends and taped to the free end
  of detcord in the satchel charge. An M60 fuse igniter was attached to the
  ends of both time fuses. The area was cleared, an engineer pulled to safety
  pins from the M60 igniters, shouted the three, “Fire in hole,” warnings,
  yanked the pull rings, igniting the fuses with a low pop, and dropped the
  charge into the shaft. There was a rough bump felt through the ground, a
  cloud of dust and smoke was expelled from the hole, and web-like cracks
  appeared around it. Another method of destroying tunnels was to pump in
  acetylene gas and detonate it with demolitions.
  The full extent of the tunnel was unknown, nor was it known if there was
  anyone inside. It is likely that there were, but they may have escaped through
  a connecting tunnel or through a bunker hidden at the edge of the village.
  Non-electric demolition
  kit
  The non-electric demolition
  kit included items issued with
  the kit plus non-explosive and
  explosive components that
  had to be requested
  separately.
  Components issued with basic
  kit
  2x demolition kit canvas
  carrying bags
  2x 10-cap capacity blasting
  cap boxes
  2x M2 cap crimpers
  2x pocketknives
  2x demolition charge
  computing tapes
  Non-explosive expendable
  components
  20x M1A4 priming adapters
  50x M1 detonating cord clips
  2x ¾in. black adhesive
  electrical insulation tape rolls
  2x ½lb cans M1 adhesive
  paste for demolition charges
  1x ½pt can waterproof
  blasting-cap sealing
  compound
  Explosive components (these
  varied in the ﬁeld)
  50x M7 nonelectric special
  blasting caps
  40x 2½lb M5A1 C4 demolition
  charges (or 80x M112)
  50x M60 waterproof fuse
  igniters
  2x 100ft detonating cord
  spools
  2x 50ft time delay blasting
  fuse coils
  2x M10 universal explosive
  destructors
  An M7 non-electric blasting cap
  is crimped to detcord using an
  M2 cap crimper. (1st Cavalry
  Division Museum)
  © Osprey Publishing • www.ospreypublishing.com
  
  A 40lb cratering charge is
  dragged into a tunnel by 
  173rd Airborne Brigade tunnel
  rats. The amount of detcord
  indicates that it will be
  emplaced a good distance
  inside. (Tom Laemlein/Armor
  Plate Press)
  56
  A city underground
  By far the largest tunnel systems were found in the Cu Chi region in the III
  Corps Tactical Zone. After realizing the extent of the tunnels, when possible
  they were explored as fully as time allowed. This proved to be a major effort,
  and units stayed on the ground for days as the searches, cordons, sweeps,
  and tunnel exploration went on.
  Our tunnel team was assigned a tunnel that had been discovered by an
  ARVN unit. They had moved on and a US rifle company now provided
  security. The entrance had been discovered beneath a stack of woven-palm
  rice-drying mats. Two hours had been spent pumping first CS and then
  colored smoke through the tunnel. Another entrance had been found under
  a trash pile of cans, tires, scrap metal, and bottles. Because it was deep under
  trash that was difficult to remove, it was assessed as an emergency escape
  hatch. The air vents with violet smoke wafting out revealed that the tunnel
  stretched at least 200m. Another hour was spent flushing the smoke out. 
  In the meantime the tunnel rats prepared their equipment and demolition
  charges and talked quietly, awaiting the word to descend into the unknown.
  Regardless of the potential size of the complex, entry and exploration
  started off just as with any other tunnel. After a few turns though, it became
  © Osprey Publishing • www.ospreypublishing.com
  
  ABOVE LEFT
  A typical shelter chamber
  inside a tunnel. The main
  tunnel continues on to the
  right. The roof is reinforced 
  by braced poles. Palm fronds
  insulate the floor, which was
  typical. (Tom Laemlein/Armor
  Plate Press)
  ABOVE
  A wider-than-usual tunnel. 
  A side room or tunnel entrance
  branches to the right side.
  (Tom Laemlein/Armor Plate
  Press)
  57
  unpleasant. The air being pumped through the tunnel had at first kept the
  stench from reaching them, but in a side tunnel they found a half-dozen bodies,
  maybe two days old. The tunnel rats were ordered to bring them up. They
  questioned the order, stating the danger of booby traps, but confirmation of
  body count was more important to some commanders than others.
  The tunnel rats in the team agreed to share the grim duty; they would
  each bring up two bodies. This entailed applying a liberal amount of Vicks
  VapoRub below their noses, even though they already wore masks, as masks
  could not keep out odors. Aqua Velva aftershave lotion was used too. After
  checking the first body as best as possible without moving it, the glove-
  wearing tunnel rat gingerly tied a rope around the ankles. Even with
  VapoRub, the stench was sickening and no one was criticized for puking up.
  The tunnel rat was pulled out and several men gave the rope a heave, but
  because of the corner turns, the body did not budge. The tunnel rat had to go
  in and pull the rope from just around the corner from the side tunnel. He
  tugged at the rope, half expecting a deadly concussive blast, but nothing
  happened. Working in shifts, they dragged out the bodies. It was
  disconcerting to some that this would be the same method by which their
  body might be dragged out, although they might first be placed in a black
  rubber body bag.
  A detailed exploration of this tunnel was possible even with the time spent
  on recovering bodies. It proved to be 2,300ft in length, with numerous
  angular turns. The shortest legs were 3ft long and the longest 30ft. The main
  tunnel was 2ft wide and 2½ –3ft high, mostly with an arched ceiling. Rather
  than bamboo tube vents, they were conical in shape, a foot across in the
  tunnel end and 2in. across on the surface. The tunnel was relatively shallow,
  owing to a high water table; it was near the Song Saigon River, so the vents
  were 5–7ft in length. About every 100m the tunnel opened into 4ft by 6ft
  rooms. These were 3ft high with a seating shelf on one side. They were used
  during bombardments and there was usually a vent present. Similar rooms
  were found at the end of the six 10–20m long branch tunnels. Large water-
  filled clay pots were buried in some of these with their mouths flush with the
  © Osprey Publishing • www.ospreypublishing.com
  
  floor. At 30–40m intervals along the main tunnel were short offshoot tunnels
  with the end walls backed by bamboo lattice work. This was pulled out of
  one and a loose earth-filled shaft was discovered. This could have been dug
  out and used as an escape route. Tools were found throughout the complex.
  Much to the disgust of one novice tunnel rat, who opened one of several US
  ammunition cans, he found that the airtight container had been used as a
  chamber pot. These were taken to the surface and dumped and washed out
  at night.
  Booby traps were seldom found deep inside a tunnel; they were too
  dangerous and troublesome to the occupants. However, one of the side room
  entrances had a punji stake pit placed so that an intruder would jam a hand
  or knee into it. One of the experienced tunnel rats found it the hard way,
  with two barbed bamboo spikes shoved through the palm of his hand. They
  had to be painfully cut off before he could be moved. With great difficulty he
  was placed on a folded poncho and dragged out, with two tunnel rats
  alternating on the exhausting job. It would have been easier to drag him on
  a body bag as they had web-carrying handles, but many soldiers did not like
  the idea. On the surface he would be given morphine and placed on an
  antibiotic IV, as it was common for feces or rotting meat to be smeared on
  punji stakes.
  H
  TUNNEL EXPLORATION
  A US unit secures the area around a tunnel entrance discovered in a rice-storage shed. A tunnel
  rat has entered the shaft while the support party on the surface prepares to assist him. Concealed
  trapdoors hide storage rooms and the tunnel entrance in the false water-well shaft. The water 
  well also serves as a water trap to block tear gas, smoke, and concussion blasts. It might also
  discourage further exploration. Two bamboo air vents can be seen, their openings hidden in
  brush. The Local Force VC would take refuge in the tunnels and hide along with their supplies 
  and munitions. It was the ultimate cat and mouse game. Tunnels might be multi-level, with
  concealed trap doors, dead ends, false walls, booby traps, and side rooms. Besides securing 
  the area while the tunnel-exploration team did its job, the infantrymen searched for additional
  entrances, air vents, fighting positions, and contraband. They also questioned villagers. This was
  as much to measure the attitude and loyalty of the villagers as it was to find information on the
  VC, of which they would reveal little or nothing.
  This tunnel entrance is
  reinforced by steel culvert pipe,
  probably of French origin. The
  figure seen here is a dummy,
  intended to draw fire. (Tom
  Laemlein/Armor Plate Press)
  58
  © Osprey Publishing • www.ospreypublishing.com
  
  © Osprey Publishing • www.ospreypublishing.com
  
  A 25th Infantry Division tunnel
  rat emerges from a village
  bomb shelter. All villages
  possessed these for the
  protection of the inhabitants,
  and they were not necessarily
  used by the enemy.
  Nonetheless, they had to 
  be searched. He holds an 
  M7 bayonet used for probing.
  (Tom Laemlein/Armor Plate
  Press)
  60
  There was a good chance that the wounded tunnel rat, even if his injuries
  healed properly, would have been in his last “black echo.” The amount of
  stress endured was high. It was easy for even experienced tunnel rats to lose
  their nerve, or feel that the odds had turned against them. They were seldom
  criticized if they shouted, “Pull me out!” It was their decision. Only they
  could assess what they were dealing with. A man could simply panic without
  warning, no matter how many times he had run a tunnel. Only he knew when
  he needed to find a new line of work. Sometimes, men went back to it after
  a break.
  AFTERMATH OF BATTLE
  Regardless of the inherent dangers, tunnel rat casualties were surprisingly light.
  Men did die in fierce hand-to-hand fights below ground, suffocate, drown, or
  become killed or maimed by booby traps. The mental stress was great, and
  post-traumatic stress disorder (PTSD) is not uncommon among former tunnel
  rats. However, it is probably not experienced at any greater percentage than
  other Vietnam combat veterans. Tunnel rats did suffer more exposure to CS
  and smoke than many other soldiers. Heavy and prolonged exposure to CS
  could cause complications if individuals later suffered from asthma and other
  respiratory illnesses. There is little evidence of this, however. Exposure to HC
  © Osprey Publishing • www.ospreypublishing.com
  
  (zinc-hexachloroethane), the compound used to make white smoke, can cause
  complications, specifically late-onset pulmonary fibrosis. It contains zinc, which
  is harmful to lungs. Tunnel rats may have been exposed to vermin and other
  filth in the course of their duties, but probably
  suffered from no more than other field soldiers.
  Field life in Vietnam was unsanitary no matter
  what precautions and efforts one undertook.
  Every soldier looked forward to the magical
  DEROS – Date Estimated Return from Overseas
  (pronounced “Dee-roes”). This was set at 365 days
  starting from the day he left the Continental United
  States. Even if delayed en route before reaching
  Vietnam, the countdown had begun. The halfway
  point was a milestone and often somewhat
  depressing, with as much time ahead of a soldier as
  he had behind him. Many men maintained a
  “short-timer calendar.” This might have been a line
  drawing of a South Vietnam map, a provocatively
  shaped and clad girl, or a helmet atop boots
  divided into 365 numbered segments, each colored
  in or marked with a cross at the day’s end.
  If a soldier had less than five months remaining
  before his Estimated Time of Separation (ETS) –
  the projected date for his release from active duty
  – he was eligible for early separation. Typically a
  conscript undertook four to five months of BCT
  and AIT, a one-month pre-deployment leave, and
  12 months in Vietnam. There might have been lag
  time between the stages of training. By extending
  for another one to three months in Vietnam they
  A VC killed while fleeing into 
  a bunker. This bunker was
  emplaced among reeds along 
  a riverbank. (Tom
  Laemlein/Armor Plate Press)
  61
  A typical short-timer calendar.
  Soldiers colored in or crossed
  off the numbered segments
  counting down to the day they
  left Vietnam and returned to
  the “real world.” (VN Center and
  Archive, Texas Tech University)
  © Osprey Publishing • www.ospreypublishing.com
  
  An exhausted 25th Infantry
  Division tunnel rat emerges
  from accomplishing a
  physically and mentally
  demanding mission in 
  the Hobo Woods. (Tom
  Laemlein/Armor Plate Press)
  62
  would be discharged immediately upon return to the United States. Many
  accepted this option rather than taking a short leave and then doing his
  remaining few months at a boring stateside post.
  All soldiers, whether three-year volunteers or two-year conscripts, were
  obligated to a total of six years’ service. They would be assigned to the
  Reserve Reinforcement Group for the remainder of their six years. This was
  a “paper assignment,” making them available for recall if necessary, but this
  would occur only if something along the lines of a world war broke out. In
  so far as is known, no such reservists were recalled. Upon completion of their
  six-year obligation they would then be discharged from service. They could
  opt to join the Army Reserve or Army National Guard.
  There is little mention of tunnel rats in unit histories. Since there were no
  tunnel rat units as such, they being ad hoc teams and volunteering individuals,
  there are few separate studies and reports other than those buried within unit
  records.
  Other than the 1986 The Tunnels of Cu Chi by Tom Mangold and John
  Penycate, little has been done to chronicle the exploits of the tunnel rats. A
  B-movie, 1968 Tunnel Rats, released in 2009 and filmed in South Africa, is
  an exaggerated and improbable story of tunnel rats, providing a totally
  unrealistic view of their experiences.
  There are no tunnel rat memorials, museums, or associations, at least in
  the United States. There is an active Vietnam Tunnel Rats Association in
  Australia (www.tunnelrats.com.au). Even the US Army Engineer Museum at
  Fort Leonard Wood, Missouri, has almost no information or displays relating
  to the tunnel rats.
  © Osprey Publishing • www.ospreypublishing.com
  
  63
  BIBLIOGRAPHY
  FM 5-25, Explosives and Demolitions, May 1967
  Foster, Randy E. M., Vietnam Firebases, 1965–73, Osprey: Oxford, 2007
  Grant, Mickey (director), The Cu Chi Tunnels, Gia Phong Film Studios, 2001
  Hanesalo, Bruce A. (ed.), Tunnel Warfare, Vol. 4: Asian Tunnel Warfare,
  Military/Info Publishing: Golden Valley, MN, 1996 (available at
  http://www.military-info.com/Index.htm)
  Lanning, Michael Lee, and Cragg, Dan, Inside the VC and the NVA: The Real
  Story of North Vietnam’s Armed Forces, Ballantine Books: New York, 1992
  Mangold, Tom, and Penycate, John, The Tunnels of Cu Chi, Presidio Press:
  Novato, CA, 1986
  MacGregor, Sandy (as told by Jimmy Thompson), No Need for Heroes: The
  Aussies who discovered the Viet Cong’s secret tunnels, Calm Proprietary Ltd:
  Sydney, 1993
  McCoy, James W., Secrets of the Viet Cong, Hippocrene Books: New York, 1992
  Rottman, Gordon L., US Army Infantryman in Vietnam 1965–73, Osprey: 
  Oxford, 2005
  ——, Vietnam Infantry Tactics, Osprey: Oxford, 2011
  Stanton, Shelby L., The Rise and Fall of an American Army: U.S. Ground Forces in
  Vietnam, 1965–1973, Presidio Press: Novato, CA, 1985
  ——, U.S. Army Uniforms of the Vietnam War, Stackpole Books: Harrisburg, 
  PA, 1989
  © Osprey Publishing • www.ospreypublishing.com
  
  64
  References to illustrations are shown in bold.
  Advanced Individual Training (AIT)  14–18
  appearance  18–20
  Army of the Republic of Vietnam (ARVN)  5, 
  34–35
  Basic Combat Training (BCT)  10–13
  battle experience  41–60
  belief and belonging  34–38
  “black echo,” the  36–37
  bomb shelters  60
  booby traps
  fragging  36
  tunnels  11, 20, 46, 49, 49–50, G (50, 51)
  boots  A (16, 17), 20
  bunkers  42, 42, 48, 52, 61
  camouflage
  tunnels  4, 5, 8, E (36, 37), 40, 46, 48
  uniforms  5, 13
  Chemical, Biological, and Radiological (CBR)
  warfare orientation  10
  chemical detachments  40–41
  chronology  6–7
  Colt M1911A1 pistols  19, 22, C (28–29)
  Colt Police Positive Special revolvers  22
  combat engineers  25, 40
  clearing vegetation  16
  searching for tunnel entrances  E (36, 37)
  training  15, 15–18, A (16, 17)
  uniforms  B (20, 21)
  communications  28, C (28, 29)
  compasses  26, C (28, 29), 48
  conditions of service  31–34
  conscription  8
  CS gas see tear gas
  Cu Chi region  56–60
  “cycle books”  13
  Date Estimated Return from Overseas (DEROS)  61
  demolition kits  55
  demolitions training  A (16, 17), 18, 18
  drug issues  35
  engineers see combat engineers
  entrenching tools  27
  equipment  24–30, 41, 43, 48, C (28–29)
  Estimated Time of Separation (ETS)  61
  field telephones  28, C (28, 29), 41, 48
  firebases  31, D (32–33)
  flamethrowers  24
  flashlights  25–26, C (28, 29), 43
  food rations  32–34
  “fragging” incidents  35–36
  gas see tear gas
  gas chambers, training in  10–13
  gas masks  9, 10
  M17 protective masks  10, 12, 20, 28, 
  C (28, 29), 43
  XM28 protective masks  28, C (28, 29), 48
  gloves  28
  grenade launchers  14
  grenades see hand grenades
  hand grenades  23–24, F (44, 45), 49, G (50, 51)
  handguns see pistols; revolvers
  headlamps  26
  helmets  9, 13, A (16, 17)
  Hi-Standard Model HD pistols  22, C (28–29)
  Infantry Advanced Individual Training (AIT)  
  14–18
  insignia  A (16, 17), 41
  kneepads  28
  knives  26–27, 48
  landmines  14
  load-bearing equipment (LBE)  24
  M2 carbines  22
  M2A1-7 portable flamethrowers  24
  M5A1 demolition charges  13
  M14 rifles  10, 14, 22
  M16A1 rifles  20, 36
  M17 protective masks  10, 12, 20, 28, C (28, 29), 43
  M20A1B1 rocket launchers  14
  M48A3 Patton tanks  50
  M60 machine guns  14
  M67 recoilless rifles  14
  M72 LAW (Light Ant-Tank Weapon)  14
  M79 grenade launchers  14
  machine guns  14
  Magnum revolvers  22
  measuring tapes  26
  Military Occupation Specialty (MOS)  10
  mines  14
  Mity Mite blowers  30, 39, 41, F (44, 45)
  mortars  39
  oxygen starvation  9, 10–11
  pistols  14
  Colt M1911A1 pistols  19, 22, C (28–29)
  Hi-Standard Model HD pistols  22
  Ruger Mk I pistols  C (28, 29)
  PM37 mortars  39
  Post-Traumatic Stress Disorder (PTSD)  60
  Quiet Special Purpose Revolvers (QSPR)  23, 23, 
  C (28, 29)
  rations  32–34
  recruitment  8–9
  revolvers
  Colt Police Positive Special revolvers  22
  Magnum revolvers  22
  Smith & Wesson Model 10 revolvers  22, 
  C (28, 29), 43
  Smith & Wesson Model 29 revolvers  23, 23,
  C (28, 29)
  rifles
  M2 carbines  22
  M14 rifles  10, 14, 22
  M16A1 rifles  20, 36
  M67 recoilless rifles  14
  rocket launchers  14
  ropes  27–28
  Ruger Mk I pistols  C (28, 29)
  scout-dog detachments  26
  search-and-clear operations  46–55
  search-and-destroy missions, ineffectiveness of  5
  Smith & Wesson Model 10 revolvers  22, C (28,
  29), 43
  Smith & Wesson Model 29 revolvers  23, 23,
  C (28, 29)
  tear gas  9, 32, 41, F (44, 45), 47, 60–61
  tear-gas chambers, training in  11–13
  tear-gas grenades  24
  telephones  28, C (28, 29), 41, 48
  training  10–18, 38
  Advanced Individual Training (AIT)  14–18
  Basic Combat Training (BCT)  10–13
  combat engineer Advanced Individual Training
  15–18
  tunnel flushers  30, 39, 41, F (44, 45)
  Tunnel Rats see also weapons
  aftermath of battle  60–62
  appearance  18–20
  battle experience  41–60
  belief and belonging  34–38
  the “black echo”  36–37
  on campaign  39–41
  chronology  6–7
  conditions of service  31–34
  equipment  24–30, 41, 43, 48, C (28–29)
  hand grenades  49
  insignia  A (16, 17), 41
  physical attributes needed  9, 18
  recruitment  8–9
  training  10–18, 38
  tunnel rat “units”  39–40
  uniforms  5, 9, 10, 12, 13, A (16, 17), 19–20, 
  B (20, 21)
  unofficial motto  5
  valor awards  38
  volunteers  8, 38
  tunnels  19, 20, 23, 34, 35, 42–55, 57, H (58, 59)
  booby traps  11, 20, 46, 49, 49–50, G (50, 51)
  camouflage  4, 5, 8, E (36, 37), 40, 46, 48
  Cu Chi region  56–60
  entrances and air vents  E (36, 37), 44, 
  F (44, 45), 46, 46, 47, 50, 58
  uniforms  5, A (16, 17), 19–20, B (20, 21)
  helmets  9, 13
  M17 protective masks  10, 12
  valor awards  38
  Viet Cong (VC)  4–5, 43, 46, 46–47, 61
  Vietnam-orientated training  14–15
  volunteers  8, 38
  weapons
  hand grenades  23–24, F (44, 45), 49,
  G (50, 51)
  knives  26–27, 48
  landmines  14
  M2 carbines  22
  M2A1-7 portable flamethrowers  24
  M20A1B1 rocket launchers  14
  M60 machine guns  14
  M72 LAW (Light Ant-Tank Weapon)  14
  M79 grenade launchers  14
  pistols  14, 19, 22, C (28–29)
  PM37 mortars  39
  revolvers  22, 23, 23, C (28, 29), 43
  rifles  10, 14, 20, 22, 36
  XM28 protective masks  28, C (28, 29), 48
  “Zero Week”  10
  INDEX
  © Osprey Publishing • www.ospreypublishing.com
  
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  First published in Great Britain in 2012 by Osprey Publishing
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  ACKNOWLEDGEMENTS
  The author is indebted to Trey Moore of Moore Militaria; David Long of
  the Tropic Lightning Museum (25th Infantry Division), Schofield Barracks,
  Hawaii; 1st Cavalry Division Museum, Fort Hood, Texas; Frederick Adolphus
  of the Fort Polk Museum, Louisiana; and Tom LaeJohn Eli (tunnel rat, 25th
  Infantry Division). Special thanks go to Tom Laemlein of Armor Plate Press
  for obtaining many of the photographs in this book.
  ARTIST’S NOTE
  Readers may care to note that the original paintings from which the
  colour plates in this book were prepared are available for private sale.
  All reproduction copyright whatsoever is retained by the Publishers.
  All enquiries should be addressed to:
  Brian Delf
  7 Burcot Park
  Burcot
  Abingdon
  OX14 3DH
  United Kingdom
  The Publishers regret that they can enter into no correspondence upon
  this matter.
  THE WOODLAND TRUST
  Osprey Publishing are supporting the Woodland Trust, the UK’s leading
  woodland conservation charity, by funding the dedication of trees.
  MEASUREMENT CONVERSIONS
  Imperial measurements are used throughout this book. The following data
  will help in converting the imperial measurements to metric.
  1 mile = 1.6km
  1lb = 0.45kg
  1oz = 28g
  1 yard = 0.9m
  1ft = 0.3m
  1in. = 2.54cm/25.4mm
  1 gallon = 4.5 liters
  1pt = 0.47 liters
  1 ton (US) = 0.9 tonnes
  1hp = 0.745kW
  ABBREVIATIONS
  AIT
  Advanced Individual Training
  ARVN
  Army of the Republic of Vietnam (pronounced “Ar-vin”)
  BCT
  Basic Combat Training
  C4
  a type of plastic explosive
  CS
  tear gas
  MACV
  Military Assistance Command, Vietnam (pronounced “Mac-vee”)
  MOS
  Military Occupation Specialty
  NCO
  non-commissioned officer
  NVA
  North Vietnamese Army
  RVN
  Republic of Vietnam (South Vietnam)
  VC
  Viet Cong
  © Osprey Publishing • www.ospreypublishing.com
  
SOURCE: textdata/thevault/Osprey System/Warrior Series (WAR)/Osprey - WAR 161 - Tunnel Rat in Vietnam.pdf