Friday, Mar. 04, 1966

The Tunnel Rats

To the Viet Cong, a shovel is as important as a rifle. Steadily increasing pressure from American ground and air power has literally pushed the Reds underground, and in the past few years they have carved out a subterranean Viet Nam that is every bit as complex as the surface one. Every city is ringed by miles of intricate tunnels; Red redoubts in the countryside are riddled with sniper-manned "spiderholes," command bunkers, storage vaults, and even underground hospitals with electricity and running water.

Like some breed of superbadgers, the Reds dig round the clock. Even hardcore V.C. troopers often dig an hour each morning instead of doing calisthenics, but most of the excavation is done by three-man teams of "volunteers"--usually village boys and girls impressed for the duty--who are expected to dig three yards of tunnel a day. The results are amazing. At Cu Chi, the newly blooded American 25th Infantry Division last month found a three-level tunnel network that snaked to 15 feet below the matted jungle and stretched more than 200 yards.

Viet Cong tunnels are shored with bamboo, take right-angle turns roughly every ten yards to baffle the blast of satchel charges dropped in the mouths of the tunnels. The Viet Cong use rabbits or gophers in open-topped cages to bore breathing holes to the surface. Headquarter complexes also have primitive "early warning" systems for air attack: conical pits five meters deep, from the bottom of which a man can hear planes miles away, as if he were resting in the cup of a giant ear.

Foiling the Fire Ants. At first, American troops simply destroyed the Red tunnel complexes. Then it became evident that intelligence, food, even weapons could be retrieved from them. In the vast Ho Bo Woods, 35 miles northwest of Saigon, U.S. troops found a 14-mile tunnel complex that contained some 100,000 documents--listing everything from names of Viet Cong terrorists to billet locations of every senior American officer in Saigon. Obviously, all tunnels would have to be explored.

In the 1st Infantry Division, that job falls to a four-man team called "the

Tunnel Rats." Since January, the team has been crawling through miles of mazes in the no man's land north of Saigon, braving booby traps and 100DEG temperatures. The Rats are an oddly equipped lot: they carry .22-cal. pistols (since .45s would shatter their eardrums at close quarters), wear leather gloves and kneepads, and are connected to the surface by half a mile of wire that runs to a battery-powered headset. Taped to their ankles are smoke grenades, for use when the Tunnel Rats are ready to emerge, and want to avoid a bullet from a startled American's rifle. Another necessity: an aerosol bomb to attack the half-inch "fire ants" that often infest the tunnels.

Notes from Underground. Once explored, the tunnels are ready for demolition. But as Captain Herbert W. Thornton, 40, Alabaman team leader of the Tunnel Rats, says: "There isn't enough dynamite in Viet Nam to blow up all of them." That problem is solved by 10 Ibs. of a crystallized riot agent called CS (O-chlorobenzalmalononitrile), developed by the British for mob control. Placed on top of a powder charge, the CS is blasted throughout the tunnel, sticking to walls and floors. When it is disturbed by returning Reds, it gets into the respiratory system and causes nausea and painful burns.

Even without CS, tunnel life is grim for the Viet Cong. A diary captured in a complex north of Saigon last week carried a typical lamentation: "Oh, what hard days! One has to stay in a tunnel, eat cold rice with salt, drink unboiled water!" That was the last entry. Next day, Tran Bang, the 29-year-old diarist, was killed in an American assault on the once-inviolable underground world of the Viet Cong.

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