A major amphibious operation was launched on 26 March in the Rung Sat Special Zone by the Seventh Fleet's Special Landing Force, and other American and South Vietnamese units.
The Rung Sat Special Zone is ideally suited for the capabilities of the Navy-Marine team. It is largely inundated at high tide and its primary lines of communications are rivers and canals. Further, it lies astride the major waterways connecting Saigon, South Vietnam's major port, with the sea.
During February and early March, the danger posed by the almost undisputed Communist control of the Rung Sat Special Zone was underscored by three attacks made on merchant shipping enroute to Saigon. The last of these came on 2 March when the Panamanian transport PALOMA was attacked and set afire in a position only four miles up river from the site where an ambush had been launched three days earlier against another merchant ship.
In the aftermath of this attack, COMUSMACV asked that the Seventh Fleet's Special Landing Force be committed for about 10 days to penetrate the Rung Sat Specia1 Zone and disrupt Viet Cong activities. Planning for the operation began on 10 March 8t the headquarters of the Naval Advisory Group, MACV. D-Day was set for 26 March, with the initial landings to come on the Long Thanh peninsula thirty miles southeast of Saigon. The naval force assigned to the operation was the Seventh Fleet's Ready Amphibious Force (COMPHIBRON ONE) consisting of flagship PRINCETON (LPH 5) with ALAMO (LSD 33) and PICKAWAY (APA 222). Attached for special operations were WEISS (APD 135) with a UDT detachment embarked, MERRICK (AKA 97), ROBINSON (DDG 12) for naval gunfire support, HENRY COUNTY (LST 824), WASHOE COUNTY (LST 1165), and RECLAIMER (ARS 42). Aircraft from HANCOCK provided daily air support for the operation.
During the next twelve days, multiple helicopter and surface landings were made by United States and South Vietnamese forces throughout the 300 square miles area in the Rung Sat Special Zone. River and coastal patrol forces supported these operations throughout the period. By the end of the operation, 63 VC were reported killed against U.S. casualties of 5 KIA, 2 missing, and 24 WIA. JACKSTAY resulted in the destruction of three major base complexes upon which the estimated 1000 Viet Cong in the area had depended. Sixty-six individual weapons were taken as well as large quantities of rice and fresh water. The latter commodities were of special importance since the Rung Sat Special Zone has no fresh water and only limited quantities of food naturally available.
The operation was significant in that it entailed the first joint United States-Vietnam amphibious operation of the war. This occurred on 31 March when the Vietnamese River Assault Groups provided a protective screen and minesweeping escort for United States Marines embarked in landing craft. The twenty-four boat convoy worked its way seven miles down the narrow Vam Sat River to make the deepest penetration of the Rung Sat Special Zone. The operation was highly successful, resulting in the destruction of large Viet Cong training, hospital, and supply complexes. This excellent penetration can be attributed to the concept of coupling Vietnamese naval experience in riverine operations with an integral body of assault troops trained in amphibious warfare.
While the areas where the Marines landed were only temporarily sanitized--not conquered--the fact that the Navy-Marine team demonstrated its ability to move freely in the area will weaken the Viet Cong hold in this area and diminish the threat they have posed to the all-important waterway lifelines to Saigon. Of added significance, forces and equipment for this operation were already available in the area, proving again the effectiveness, applicability, adaptability, and flexibility of the Seventh Fleet's amphibious and Marine units.