On April 6, 1967, 20-year-old Doug Hegdahl was knocked overboard by the blast from a 5-inch gun mount from the USS Canberra in the Gulf of Tonkin, 3 miles off the coast.
He swam until he was picked up by Cambodian fishermen who treated him well. He was eventually handed over to the NVA and sent to the "Hanoi Hilton" prison.
The interrogators first believed that he was a commando or an agent. His story of being blown overboard seemed unbelievable to the them, but after a few days he was able to convince his captors that he was of little value to them.
When asked to write statements against the US, he pretended to be unable to read or write. Thinking they had someone who would be easily turned to their cause, they assigned someone to teach Hegdahl to read. After he appeared to be incapable of learning to read and write, his captors gave up on him. Later, he came to be known as "The Incredibly Stupid One", and he was given nearly free rein of the camp.
Hegdahl memorized names, capture dates, method of capture, and personal information of about 256 other prisoners—to the tune of a nursery rhyme "Old MacDonald Had a Farm".
He also convinced his captors that he needed new glasses and memorized the route from the prison into the city of Hanoi, where he was taken to be fitted.
During his prison stay, Hegdahl disabled five trucks by putting dirt in their fuel tanks.
He was one of 3 POWs who were released on August 5, 1969, as a propaganda move by the NVA. Although the POWs had agreed that none would accept early release, they agreed that Hegdahl's release should be an exception.
He was ordered by the officer in charge to accept the release so that he could provide the info he memorized, to which he did; confronting his captors in the 1970 peace talks.