A U. S. Navy patrol air-cushion vehicle (PACV) moves out on a mission in the Mekong Delta region of South Vietnam in January 1968. Initially three PACVs were deployed to Vietnam in 1966 for operational testing and evaluation. After a year in which they participated in operations related to Market Time and with Gamewarden forces, they were returned to the United States for modification and upgrades. They later served two additional tours in the Vietnamese swamps and deltas.