In July 1965, a U.S. Coast Guard unit designated as squadron 1 arrived in the waters of South Vietnam to form the key link in a unique coastal surveillance force. The arrival of that unit marked the inception of "Operation Market Time," a joint Navy-Coast Guard mission designed to prevent North Vietnam from infiltrating men and materials of war to the Vietcong. Since 1965, Coast Guard duties in that area of the world have gradually expanded in scope and importance.