"Bill" an Aussie tunnel rat emerging from a tunnel. Click photo to enlarge. Note the "Australia" badge and the name written on the bush hat. Photo from Vietnam Remembered.

Unofficial motto 

"Non gratum anus rodentum" 

"Not worth a rat's arse" 

or alternatively

"Couldn't Give a Rat's Arse"

Knife of type that would be carried

Flashlight

Colt .45 Auto (above)

Smith & Wesson .38 (lower)

HOW IT ALL BEGAN:

Friday 7th of January 1966. The 1st Battalion of the 28th Infantry, itself part of the 3rd Brigade of the 1st Inf Div - "The Big Red One"- was engaged in operation "Crimp". The first search and destroy sweep into the VC held area's Northwest of Saigon. Operation "Crimp" was intended to be a massive strike against the VC in South Vietnam; in and around the Ho Bo woods just west of the Iron triangle.

Even as the men from the 1st Batt 28th Inf touched down on LZ (landing zone) "Jack" they could see their comrades in the 1st Batt 16th Inf were already in trouble and engaging the enemy in small fire fights. The men quickly de-assed their helicopters and moved into the nearby tree line hoping to find, engage, and destroy the VC that had been harassing the soldiers of the 16th Inf.

Just inside the tree line at the edge of a rubber plantation, the men of the 28th discovered a large trench - but no enemy. Where had they gone? How could the VC who had been firing at the men of the 16th Inf just disappear apparently into thin air? As the Batt moved forward it began to find large caches of rice, and enough food to feed a Regiment. As the operation continued, over the next couple of days foxholes, trenches, and caves were discovered. Still no enemy were being engaged in running fire fights, or surrendering, and all the time US casualties were mounting through sustained enemy sniper fire.

By the 10th of January the 28th had reached the banks of the Saigon river. So far during the 3 days of the operation only a couple of brief glimpses of the enemy had been seen. Late in the afternoon of the 10th word came through via the radio that elements of the 173rd Airborne Brigade and the Aussies to the north had made contact with the VC and - found tunnels.

The next day the 11th of January the 28th began to retrace it's foot steps. It had finally dawned on the Battalion Commander LTC Robert Haldane what had happened - they had literally walked right over the VC! Searches were begun for the tunnel entrances but nothing much was discovered. By now hot and tired, and waiting for further instructions some of the GIs began to sit down for a quick rest.

Sergeant Stewart Green did the same, but only momentarily, as he suddenly leap to his feet cursing that something had bitten him on the ass. Thinking he'd been stung by a scorpion, or worse, bitten by a snake, Green searched through the layer of dead leaves that covered the area looking for the creature that bitten him. Only to discover it was a nail sticking up from the ground. Upon further careful inspection it was discovered that the nail was part of a small wooden trap door - Haldane's men had found their first tunnel!

THE TUNNEL SYSTEM:

Originally the tunnels were started during the war against the French, but which were rapidly expanded upon when the American's arrived. They were constructed by volunteer(!) village labourers using simple hoe's and baskets. The Laterite clay in which the tunnels were dug has a dull reddish appearance and dries rock hard during the dry season. During the wet season it is very soft and much easier to work. Because of the very nature of the Laterite clay's ability to dry rock hard it made a very good (if a somewhat difficult substance to work) soil in which to carve out a tunnel. 

The passages themselves were not cut in dead straight lines, rather they were made with corners that had between a 60 - degree and a 120 - degree angle to them. In other words the corners were constructed with no less than a 60 - degree angle and no more than a 120 - degree angle. This made shooting in a straight line impossible, and helped to deflect explosive blasts from grenades that might be thrown down.

The tunnel systems (where the water table permitted) had several levels, each level was separated by a watertight trap door which would seal the rest of the system against gas, flooding, etc. The trap doors themselves were virtually undetectable and could fool a person into believing that the tunnel finished in a dead end, when in reality it led into a huge system of other passages. These passages would in turn lead to underground ammo dumps, kitchens, air raid shelters, hospitals, store rooms, workshops, latrines, and even theatres for the performances of political plays.

All the tunnel systems had smaller thin (drain pipe sized) ventilation shafts leading from the surface down to the 1st level. These vents were constructed with an oblique angle so as to prevent the monsoon rains flooding the system. Vents were placed so as to face east and the light of a new day, whilst others were placed toward the wind so as to provide a constant cooling draught. Despite these efforts the tunnels were still hot, dark, and claustrophobic, even at the best of times.

The VC also dragged the bodies of their dead comrades underground in order to inter them in temporary graves when it became impossible to bury them above ground due to the presence of American/Australian troops. Once they had been dragged underground they were buried in the foetus position in the tunnel walls and covered with a thin layer of clay.

THE OP ENGINEER (Tunnel Rat) (an underground man) The leading scout raised his arm in the village of Long Phuoc He'd found another tunnel, but who'd go down to look? The corporal passed the word back, it went back far behind To let his platoon commander know of his recent find Then along came this soldier, with mud from head to toe "Where's the tunnel entrance?" was all he wanted to know When they showed the soldier, he quickly looked around And before you could stop him, he'd gone underground Now he'd been searching on his gut, all that day I bet Look out for booby traps that good ol' Charlie sets Then he found the wire, stretched out taut and thin But he deloused that booby trap, with a safety pin Then he found the weapons leaning on the wall There was no disputing he'd found a real big haul When he finally surfaced, wearing a big grin He proudly showed the Diggers what he'd found within Now he'd like to sit down, and roll himself a smoke But he's been called up forward, by another bloke So when you see that hat badge, that's like a bursting shell Remember that this fellow has crawled half way through to hell And if he's in a bar mate, you buy that bloke a beer Because Sir, you're drinking with an Aussie Engineer

A SPECIAL BREED OF MAN:

Originally called "Tunnel Runners" by the 25th Inf Div, and "Ferrets" by the Australian Army, the term "Tunnel Rat" soon became their official accepted name. The US Army soon realized that trying to destroy the tunnels was a short-sighted policy that wasn't going to work. Moreover this was also a loss as the underground networks could yield vital intelligence on the VC in the form of plans and documents.

A chemical officer of the 1st Inf Div, Capt Herbert Thornton a Southerner, was charged with setting up the first tunnel team.

The kind of man that Thornton sought for his tunnel team had to be a special breed. He had to have an even temperament, an inquisitive mind, a lot of common sense (in order to know what to touch and what not to), and to be exceptionally brave.

All of Thornton's men were volunteers, most (not all) were small men of slight build who could squeeze through the tight trap doors and crawl along the narrow passages with relative ease. 

• No dead tunnel rats were left in a tunnel, dead or wounded they were all dragged out with commo wire, ropes, or by a comrade using a fireman's crawl. 

It was a very stressful, nerve racking job, pushing the rat's mental state to its limits. Crawling through narrow, pitch black tunnels, sometimes for hours looking for a heavily armed enemy who would if he got the drop on you not hesitate to kill you. Occasionally under the strain a mans nerves would break and he'd be dragged from the tunnel screaming and crying. Once this happened he would never be allowed down a tunnel again.

If going down into a tunnel posed a threat, then coming up again could be just as dangerous. Upon emerging from a tunnel a rat would often whistle "Dixie" just to let the troops on the surface know he was on their side. A little guy stripped to the waist and covered in dirt could easily be mistaken (particularly if he was oriental looking) for a VC and shot by his own side.

TRAPS AND CREEPY CRAWLIES:

Going down into a tunnel system was a very risky business fraught with danger. Usually armed only with a pistol or a knife and a flashlight. The tunnel rat would descend into a pitch black, claustrophobic, dank hell, to play a deadly game of hide and seek with the enemy. Carefully probing the floor, sides and roofs of the tunnels became second nature to the tunnel rat as he gently inched and probed his way along. Feeling for wires or tree roots that didn't quite feel right, knowing that anyone of them could detonate a booby trap and blow him to smithereens.

Tunnel entrances were sometimes mined or covered by concealed firing positions. On other occasions an entrance would drop into a punji stake pit which would be covered by two rifle men, one either side. Another way in which the unsuspecting tunnel rat could meet his death was by garrotting him or cutting his throat as he came up through a connecting trapdoor. Besides the booby traps the tunnels also held other nasty surprises. Living along side the VC was a whole plethora of animals which had also made their homes in the dark confines of the tunnels. Bats (the cave dwelling nectar eating bat and the black bearded tomb bat) would use the tunnels as a roosting ground during the daylight hours. 

A tunnel rat crawling through a tight tunnel would wake them from their rest causing them to fly right at him, getting tangled in his hair and running and crawling all over him. Snakes were also encountered underground. Two of the most deadly being the bamboo viper and the Krait. Sometimes the VC would deliberately tether a snake in a tunnel to use it as a sort of natural booby trap.

Scorpions were also used as booby traps, the VC would take boxes of them into the tunnels. The box would be rigged with a trip wire, the tunnel rat tripped the wire and the scorpions would fall on him stinging him in the process. Being stripped to the waist and slowly crawling along on their stomachs also exposed the rats to bites from fire ants that inhabited the underground labyrinths. Other nasties to be encountered in the tunnels were real rats, and spiders like the Giant Crab Spider. Sometimes whole chambers were crawling with a thick black mass of tiny spiders the size of a thumb nail, giving the illusion that the walls were moving!

TOOLS OF THEIR TRADE:

It was soon discovered early on that to fight in the tunnels the tunnel rat had to do away with most of the infantry mans basic load. In fact the total lack of equipment carried by a rat was a distinct advantage, which greatly increased his chances of survival. The basic tools of the tunnel rat were the knife, the pistol, and a flashlight.

Knife of type that would be carried	Flashlight	Colt .45 Auto Smith & Wesson .38

The pistols that were carried by the tunnel rats were varied, the .38 Smith and Wesson was a favourite. Other tunnel rats procured their own personal firearms to suit their own needs. One of these was Master Sgt Flo Rivera who acquired and used a 9mm German Luger. The one weapon everyone agreed about was the Colt .45. It was too big, with a silencer it was to cumbersome and when it was fired underground without a silencer its bark was deafening. Making it impossible to hear the enemy.

One of the tunnel rats golden rules was you never fired more than 3 shots underground without reloading, as the VC would know you were out of ammo.

The flashlight was the standard Army issue type and every rat carried one. These were carried in a way so as not to make themselves a nicely illuminated target. If the bulb in the flashlight went it had to be changed. This was practiced so it could be done in pitch darkness by touch alone, and done quickly, lying prone, squatting, or kneeling down. 

 THE TUNNEL EXPLORATION KIT:

Due to the specialised nature of tunnel warfare, priority was placed with ENSURE (Expedited Non-standard Urgent Requirements for Equipment) program for the development of special "Tunnel Exploration kits". Six kits were requested by USARV on the 29th of April 1966, and then passed on to ACTIV (Army Concept Team In Vietnam) on the 7th of August. ACTIV then distributed the six kits, two went to the 1st Inf Div at Di An, a further two were dispatched to the 25th Inf Div at Cu Chi. Of the remaining kits one was given to the 1st Cav at An Khe, whilst the last remaining kit went to the 173rd Airborne Bde at Bien Hoa.

Each kit cost 728 Dollars and consisted of a .38 calibre pistol which was fitted with a suppressor and a spotlight sighting device. This was all carried on a standard pistol belt in a specially designed holster. On the wearers head was a baseball cap which had a miners lamp mounted on it which was switched on and off via a mouth operated bite-switch. At the back of the cap was a bone conduction microphone communication system which was connected to a small ear piece. The power pack for the lamp and a communication wire reel were also hung on the pistol belt, but were situated on the wearers back.

Tests on the exploration kit in Vietnam soon revealed its short comings. The silenced .38 cal pistol was not liked because of its length with the suppressor, and because it lacked balance and was awkward to handle. The special aiming light was found to be unnecessary given the tight confines and short ranges the tunnel rats were operating in. The huge pistol holster was also a failure as it was too big and unwieldy to be used in the tight confines of a tunnel. The head mounted miners lamp fared no better! This was obstructed by the baseball cap's visor and could be shorted out by switch malfunctions rendering it useless. Furthermore the lamp tended to slip down over the wearers eyes. The earpiece part of the communication system was also troublesome as it kept falling out of the wearers ear!

USARV requested 250 tunnel kits on the 21st of March 1967, but because of a mix up in the ordering quantity (500 instead of the original 250) and year end budget problems, immediate funding was slow in coming. Natick labs were not asked to produce the sets until the 30th of September, this situation was further frustrated by problems in the communication equipment for the kits. Eventually the requested 250 sets were delivered to Dover AFB between the 22^nd and the 29th of May 1968, and from there immediately flown to Vietnam.

With their patch with it's nonsense Latin motto "Non gratum anus rodentum - Not worth a rats ass" the tunnel rats were among the bravest in Vietnam, doing a job that not many others could, or would care to do.

partly from http://www.diddybop.demon.co.uk/tunnel1.htm