Operation Thunderhead was a highly classified combat mission conducted by U.S. Navy SEAL Team One and Underwater Demolition Team 11 (UDT-11) in 1972. The mission was conducted off the coast of North Vietnam during the Vietnam War to rescue two U.S. airmen said to be escaping from a prisoner of war prison in Hanoi. The prisoners, including Air Force Colonel John A. Dramesi were planning to steal a boat and travel down the Red River to the Gulf of Tonkin.