Operation Market Time was the United States Navy, Republic of Vietnam Navy and Royal Australian Navy operation begun in 1965 to stop the flow of troops, war material, and supplies by sea, coast, and rivers, from North Vietnam into parts of South Vietnam during the Vietnam War. Also participating in Operation Market Time were United States Coast Guard's Squadron One and Squadron Three. The U.S. Coast Guard operated under U.S. Navy command heavily armed 82-foot (25 m) patrol boats and large cutters that included 5-inch naval guns used in battle and gunfire support.