The tunnels occupied three levels. At the top level were shelters to accommodate medical services, cooking, artillery, and food storage.bb
These shelters were big rooms located only 3 metres below surface. Two more levels of tunnels are located 8 metres and ten metres below surface respectively. The second level was used as a bomb shelter because the B52 carpet bombing would only penetrate up to 5 metres. The middle level was ‘A’ shaped to withstand the blasting. The bottom level was used for escape because it emptied into the Saigon River.
Since nobody knew about them, in many instances, the US military set up camp right on top of them. Initially the Viet Cong did not attack at night, what they did was to come up to surface at night, steal the American food and ate it, stole American soap and bathed in it, stole American clothes and put them near the exhaust shafts. The Americans had search dogs but the dogs couldn’t distinguish between the Viet Cong and the Americans because of the VC use of American products.
There was no design to the caves so no one could fully describe them under torture. Also it was broken up into section A,B,C, so no single VC knew anything about the tunnels outside his section. If someone from A group needed to go to B group, he would need to be escorted. To distinguish real VC from spies and rates they had a code. They would give a number and the responding number had to add to nine. The password also changed every day.
I am beyond claustrophobic and balked at descending into the tunnels. Rene, however was good enough to take one for the team so that I could have a photo.
"I've spent my whole career in underground mining," he later shook his head. "And even I didn't feel very comfortable down there."
VC troops averaged 26 days underground in rotation. They would spend their entire daylight hours underground and only come out after dark for exercise or raids. They had underground toilets (vertical shafts to the side) and water containers were used as portable toilets. They used lime to disinfect. No lights were allowed underground except for a candle when actively tunneling. There is a very small (3 inches in diameter) ventilation shaft every ten metres or so. At night, they would go to surface, collect young bamboo and drive it from a tunnel to surface. Then the termites would come in because they love young bamboo. They’d eat out the bamboo, creating the shaft, and leave a termite mound on the surface. Since there were termite mounds all over, it didn’t draw attention to the shafts.
All the tunnels and entry ways were VC size (v. small) so even if the Americans found them, they couldn’t squeeze into them. So the Americans used South Vietnamese and Mexican enlisted personnel (called ‘rats’) to go down to try to flush them out. They were unsuccessful.
The VC also periodically created a U shaped tunnel so that if the Americans tried to gas them out, they could seal the u-bend with water. The Americans tried to flood them out, but since the tunnels drained into the Saigon River, that didn’t work either.
Photos: R. Marion
Coming up next: Sensational Saigon
There were three cardinal rules,
1. Talk no voice. Developed a method of communication without speaking because the Americans used listening devices.
2. Cook, no smoke. They cooked once a day and they used multiple scrubbers (little chambers) from the cooking area to disperse the smoke. When the smoke finally came up in a very thin stream, it was twenty or thirty meters away. If the Americans found the ventilation duct it was nowhere near the kitchen.
3. Walk with no trace. They did that by making their sandals out of tires and made them square so direction of walking was impossible to determine.