The primary objective of the Market Time coastal patrol was to prevent the enemy from strengthening his forces in South Vietnam through seaborne infiltration of supplies and munitions. The North Vietnamese Naval Transportation Group 125 used steel-hulled, 100-ton trawlers and seagoing junks to infiltrate the South. The Viet Cong operated smaller junks, sampans, and other craft within South Vietnamese coastal waters, and limiting this movement also became a responsibility of the Market Time forces.
The coastal surveillance operation was organized around nine (initially eight) patrol sectors covering the 1,200-mile South Vietnamese coast from the 17th parallel to the Cambodian border and extending 40 miles out to sea. Within these areas, ships and craft of the U.S. Navy searched for contraband. American aircraft operating from ships offshore and from bases in South Vietnam, Thailand, and the Philippines flew search patterns over the Market Time area. By 1968 the patrol generally was divided into three zones: (1) an air surveillance sector farthest out to sea; (2) an outer surface barrier patrolled by large U.S. ships; and (3) an inner, or shallow-water, barrier patrolled by U.S. and South Vietnamese boats and craft and Coastal Force junks. Mobile units of Inshore Undersea Warfare Surveillance Group 1, Western Pacific Detachment, deployed to South Vietnam in April 1966 to form an additional screen.
Recognizing that the sea was a likely avenue of approach for Communists infiltrating from North Vietnam or moving along the South Vietnamese littoral, in April 1960 the navy established the paramilitary Coastal Force. In line with its emphasis on counterinsurgency warfare, the Kennedy administration wholeheartedly endorsed the development of this junk fleet, providing the force with American naval advisors, boat design and construction funds, and stocks of small arms. By the end of 1964, the 3,800-man, 600-junk force patroled the offshore waters from 28 bases along the coast. To coordinate the operations of these 28 separate divisions, U.S. advisors helped set up coastal surveillance centers in Danang, Cam Ranh, Vung Tau, and An Thoi, the respective headquarters of the 1st, 2d, 3d, and 4th Coastal Districts.
Of the three major combat commands in the Vietnamese Navy, the Coastal Force was most beset by problems. By mid-1968, hull and equipment deterioration and the disposal of inefficient sailing junks had reduced the number of vessels in the 600-craft force by half. Of the remainder, almost one-third were not operational for lack of repairs, spare parts, supplies, or fuel. The addition to the force of the newly constructed Yabuta junks only partially offset this loss of operational vessels. The Yabuta, fiberglass- hulled to retard damage from marine borers, was crewed by five men and armed with .30-caliber and .50-caliber machine guns and other automatic weapons. The craft, powered by 110-horsepower Graymarine diesel engines, could reach speeds of 10 to 12 knots.
Personnel problems proved equally vexing. Although authorized almost 4,000 men, the Coastal Force often fell short by 700 to 800 men. Lacking the prestige of the other combat branches and with its men underpaid and isolated in austere bases, the junk force had great difficulty recruiting personnel, especially those with technical knowledge. Further, only a few of the coastal group bases created formal training programs to increase the skills of those men enlisted. Encouraged by U.S. naval advisors, the Vietnamese Navy took limited steps in late 1967 and 1968 to improve the training effort and to better the living conditions of the junkmen, but much remained to be done.
By 1969 the Coastal Forces of the VNN consisted of 20 coastal groups. Each of the coastal groups was subordinate to one of the four VNN Coastal Zone commanders. A coastal zone corresponded geographically to one of the four CTZs with the exception of III CTZ which extended into IV CTZ. The primary mission of the groups was to conduct coastal surveillance in order to prevent infiltration from the sea and to prevent illegal coastal transshipment of military contraband. The secondary missions included the support of small unit amphibious warfare operations, resources control, intelligence, and psychological warfare operations. Because of the variance in the tactical situation which existed in the vicinity of the coastal groups, their make-up varied considerably, using assets of Command, Yabuta, and Kien Giang junks as required.
The River Forces included the RAGs, RAIDs, and RPGs. The Vietnamese grouped their riverine assault craft in Riverine Assault Interdiction Divisions (RAID) and their PBRs into River Interdiction Divisions (RID) and River Patrol Groups (RPG). They also augmented the existing RAGs and coastal groups, the latter now consolidated into 20 units for lack of sufficient patrol junks.
The primary missions of these groups were amphibious assault and interdiction operations. Their secondary mission was riverine security/waterway control. RAGs 81 and 91 were responsible for escorting shipping and minesweeping on rivers and canals of the Delta. There was no Vietnamese commander of the River Force; however, the commanders of TF 211, 212, 214, Third and Fourth Riverine Areas, who commanded the RAIDs, RAGs, and RPGs had advisors assigned to coordinate information and studies on the various components of the River Forces. River Forces were composed of 12 RAGs, six RAIDs, and four RPGs.
Confident of the coastal patrol's effectiveness, Commander Coastal Surveillance Force began early the Vietnamization of the Market Time effort. The ACTOV program of the Navy and the SCATTOR (Small Craft Assets, Training, and Turnover of Resources) plan of the Coast Guard entailed the phased transition of the Vietnamese Navy into complete control of the inshore barrier, then the high seas surface patrol, and finally a coastal radar network intended to replace the American air surveillance effort. In September 1970, as Task Force 115 turned over the last of the PCFs and WPBs, the Vietnamese Navy took charge of the inner barrier.