The recent news in Israel regarding the extensive network of tunnels dug by Hamas to infiltrate into the country from Gaza reminded me of some of my reading I did previously on the Vietnam War and our involvement in it.
The Cu Chi tunnel complex just outside of Saigon stretched over 150 miles extending all the way to the Cambodian border. The tunnels were dug by hand and were used to link Viet Cong support bases, lay booby traps, and mount surprise attacks where they could disappear afterwards underground. The tunnels included
entire underground villages, in effect, with living quarters, kitchens, ordnance factories, hospitals and bomb shelters. In some areas there were even large theaters and music halls to provide diversion for the troops (many of them peasants) and their supporters.How effective were the tunnels for the Viet Cong?
``Time and again the Viet Cong would execute hit-and-run raids and simply melt away,`` Mangold says. ``They vanished because elaborate networks of tunnels and caves connected villages, districts, even provinces. These evolved as the response by a poorly equipped guerrilla army against massive modern war technology.The tunnels were so well hidden the USA constructed a massive 1500 acre base above the Cu Chi tunnels where
``The tunnels, thus, had great symbolic significance to the Viet Cong. They became convinced that if they persevered and maintained an active presence, they could win the war.``
Charlie had a field day then, blowing up planes and equipment from within the perimeter. It later came out that even the base barbers--all 13 of them--were Viet Cong.``How did the USA combat these tunnels?
The secret Cu Chi tunnels were ``like a thorn stabbing the enemy in the eye,`` a VC officer told Mangold. The guerrillas lost 12,000 people there, but still were able to infiltrate Saigon with intelligence agents, party cadres and sabotage teams. The 1968 Tet Offensive was planned and launched underground; the tunnels housed thousands of troops.
``Everybody in Saigon knew that Charlie was all over Cu Chi, but no journalist knew about the tunnels,`` Mangold says. ``The place was a free-fire zone--the most bombed, shelled, gassed, defoliated and devastated area in the history of warfare. From hotels in Saigon, we`d watch returning planes routinely dump unused bombs and napalm over Cu Chi.``One USA operation conducted jointly with Australia involved over 8000 men in an attempt to sweep the tunnels that ultimately failed. A year later another 60000 men attempted the same in the Iron Triangle but the cleared area returned to VC control after a few months utilizing the still available tunnel network.
The USA eventually trained 'tunnel rats', usually men of smaller stature to go down with a flashlight and a small caliber pistol to look for booby traps and enemy soldiers. Additional methods to destroy the tunnels over and above the B-52 carpet bombing, large scale attacks and use of tunnel rats were efforts at flooding the passageways, using tubing to insert liquid explosives, conventional explosives including Bangalore torpedoes and lastly acetylene.
Most effectively, engineers used acetylene for destruction of tunnels with less than 7 feet of over-burden. A charge could ignite an acetylene-air gaseous mixture generated from a calcium carbide and water reaction. Four cubic yards of acetylene pumped into an area could destroy more than 50 cubic yards of tunnel volume. When acetylene was used in conjunction with conventional explosives, the effect could collapse 15 feet of overburden. But this latter method also involved inherent danger due to volatility of the chemical compounds.All of these methods ultimately failed to eradicate the tunnels and today Vietnam offers tours of the Cu Chi complex to visitors.