Sappers were a constant threat to men and equipment in the Vietnam War. Men on motorcycles would race through the streets of cities and towns with satchels filled with explosives, what are now sometimes called IEDs (improvised explosive devices). They were very effective against groups in urban areas and intended primarily to instill fear in the population.
At Cua Viet the threat was not on land but on the river. Enemy swimmers would try to sink boats by attaching explosive devices to the bottom of boats. NVA “frogmen” using primitive underwater breathing devices would attach an explosive charge to the boats when they were tied up in the harbor or anchored out in the shallow streams. They were not all that effective but did cause some damage and frustration to the boat crews.
One day as I was walking along near the loading ramp I heard a muffled explosion and saw the stern of a YFU (cargo vessel) lifted up nearly out of the water. The boat had probably just left Cua Viet loading area after having discharged its cargo and was heading out of the mouth of the river. The explosive device had evidently been placed on the boat while at Dong Ha or perhaps our loading ramp at Cua Viet.
Although swimmers were occasionally spotted, we never captured any of them. One time some NVA underwater gear was recovered and turned over to me, the staff intelligence officer. Someone snapped a picture of me examining the items recovered.
CAPTAIN Herman Woodrow Hughes, US Navy, Retired Vietnam 1968