Douglas Brent Hegdahl III is a former Petty officer second class of the United States Navy sailor who was a prisoner of war during the Vietnam War. Hegdahl was born on September 3, 1946, and graduated from high school in Clark, South Dakota. 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, three miles off the coast. Hegdahl was turned over to Vietnamese militiamen who clubbed him repeatedly with their rifles before moving him to the infamous "Hanoi Hilton" prison. The interrogators first insisted that Hegdahl was a commando or an agent. Hegdahl quickly realized he would be much better off if he pretended to be a lowly fool. Hegdahl was slapped around for a few days before convincing his captors that he was of little value to them.
Thinking they had someone who would be easily turned to their cause, they assigned someone to teach Hegdahl to read. After Hedgahl appeared to be incapable of learning to read and write, his captors gave up on him. With the help of Joe Crecca, a U.S. Air Force officer and fellow prisoner, 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". Hegdahl is still able to repeat the information to this day. According to his senior officer and cellmate, Lieutenant Commander Richard A. Stratton, Hegdahl 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 gas tanks. Hegdahl was one of three POWs who were released from Hanoi on August 5, 1969 as a propaganda move for the North Vietnamese. Hegdahl was sent to the Paris Peace Talks in 1970-and confronted the North Vietnamese with his first-hand information about the mistreatment of prisoners. After returning to the U.S, Hegdahl used his experiences as an instructor at the United States Navy's SERE school based in NAS North Island, San Diego, California.