 In addition to naval militia training duties, some of the surviving units have been converted into target drones, and have thus been returned to active service, functioning as minor support auxiliaries.As with the , the drone is controlled by larger converted gunboats such as the , , and classes.Three P-4 class torpedo boats (T-333, T-336, and T-339) in the service of the Democratic Republic of Vietnam were launched an abortive attack on the American Allen M. Sumner-class destroyer USS Maddox in August 2, 1964 in the first Gulf of Tonkin incident (see Edwin E. Moise, Gulf of Tonkin and the Escalation of the Vietnam War, University of North Carolina Press