Following the French defeat at Dien Bien Phu in 1954, the United States Military Assistance Advisory Group (Indochina) (USMAAG Indochina) became USMAAG (Vietnam) and with this transition, the United States became even more deeply involved in the affairs and prerogatives of the South Vietnamese (Republic of Vietnam) regime. Wisely, President Eisenhower firmly resisted the urgings of some advisors to send in troops, but he did expand the role of military advisors and in time, all US armed services were represented on the USMAAG (Vietnam) staff.
In 1960, newly elected John F. Kennedy approved the USMAAG’s request for increases in the size of the South Vietnamese Army (also, Army of the Republic of Vietnam or ARVN) and an increase in the number of military and civilian advisors. As Henry Bohn told us in 1855, the road to hell is paved with good intentions. John Kennedy began excavating a hole our government couldn’t stop digging.
Lay of the Land
The Mekong Delta extends from Saigon (now, Ho Chi Minh City) south and west to the Gulf of Thailand and the border with Cambodia. Its area extends nearly 29,000 square miles and it is home to an estimated 15 million inhabitants. In all, the Mekong Delta constitutes about a quarter of the total land area and half the population of the former Republic of Vietnam. The Delta is a flat alluvial plain created by the Mekong River, a land surface covered by rice paddies, which makes this region one of the world’s most productive rice-growing areas. It is by far the most important agricultural region in Vietnam.
In terms of overland communication, the Mekong Delta was an unmitigated disaster, as the region is intersected by a complex network of waterways and inundated by heavy rain and seasonal floods. In 1960, there was but one major hard surface road, which extended from Saigon to Ca Mau. Secondary roads were either poorly surfaced or unattended. While the land facilitated air combat operations, poor road systems, rice paddies, canals, wide ditches, and rivers complicated ground operations. In contrast, the waterway system was very sophisticated, and the US MAAG realized early on that if the US intended to pacify the Mekong Delta (also, IV Corps Tactical Zone, or IV CTZ), it would have to consider implementing riverine operations.
Most Vietnamese in this area are concentrated along waterways that constitute the principal transportation routes, on average, around 400 people per square mile. Typically, Vietnamese homes are surrounded by dense trees, shrubs, and bushes —cultivated for fruit, shade, or decoration. The vegetation was pleasing to look at, but it also gave protection and concealment to communist insurgents. When planning for operations in the IV CTZ, US military officers wanted to take the war to the enemy but do so without endangering local inhabitants. With its population density, it was nearly impossible to move friendly forces without their being observed by unfriendly eyes. The enemy always seemed to know when Uncle Sam was coming for a visit.
Vietnam’s Delta seacoasts have an extensive network of mangrove swamps. Vegetation on the coastal mudflats is dense, root structure high, and tangled, which makes access difficult and cross-country movements challenging. Rice paddies are separated by thickets of trees in varied patterns. Large cultivated plantations are marked by rows of palm trees, many of which border deep ditches or wide canals. Operational planners for riverine operations had to factor in water, vegetation, terrain, and the influence of sea tides; it also involved guesswork. There was no way to accurately predict travel or operational times.
The Mekong Delta (IV CTZ) was rife with communist insurgents … estimated at around 84,000 men in 1966. Of those, around 20,000 were trained and well-armed combat troops with about 51,000 part-time guerrillas. In 1966, there were no North Vietnamese Army (NVA) forces operating in IV Corps. Logistically, Viet Cong forces relied on support from local populations and whatever could be provided from North Vietnam. Cambodia, bordering IV CTZ, was a haven for supplies moving down from the north.
ARVN forces in IV CTZ were subdivided into three divisional tactical zones: in the north, the 7th ARVN Division at My Thơ, in the center, the 9th ARVN Division at Sa Dec, and in the south, the 21st ARVN Division at Bac Lieu. In total, around 40,000 men, including five ranger battalions and three armored cavalry squadrons. Regular forces were augmented by Regional, Popular, and Irregular troops, and the National Police. The conventional wisdom (back then) was that anyone joining Regional or Popular Forces organizations was “just asking for it” (VC assassination). Unsurprisingly, both groups had high desertion rates, and the thing that made irregular troops so irregular was that one could never find them when they were needed.
Vietnamese naval forces in the 4th Naval Zone evolved from the French Dinassauts and included six river assault groups and eleven coastal groups that formed the so-called Junk Fleet. Assault groups fell under the IV CTZ Commander; their primary mission was supporting ARVN riverine operations. Each group could lift an ARVN infantry battalion. In 1966, these units were used in their primary role about 10% of the time. The reason for this was that the ARVN battalion commanders preferred airmobile operations; they were more fun and had greater visibility for purposes of promotion.
United States Navy advisors entered the Mekong Delta in 1957 to replace the withdrawing French. By 1966, the military advisory effort infused the entire RVN military structure. In total, around 2,700 officers and enlisted men representing the Army, Navy, Marine Corps, and Air Force were assigned to corps, division, and provincial organizations, and the IV CTZ Area Logistics Command. The USN Advisory Group (RVN) provided advisors to the Vietnamese Navy’s six river assault groups and eleven coastal groups.
In 1965, the U. S. Army’s 13th Combat Aviation Battalion was assigned to the Delta to support ARVN operations; by August of that year, the battalion operated four assault helicopter companies and one air reconnaissance company. By mid-1966, naval forces included TASK FORCE 115 (also, MARKET TIME) and TASK FORCE 116 (also, GAME WARDEN). The mission assigned to Market Time was interdiction of coastal areas to prevent resupply of VC forces by sea. Game Warden was tasked with interdicting enemy lines of communications and assisting ARVN forces in repelling enemy attacks on river outposts of Regional and Popular Forces. Despite the optimism of the American administration, which predicted a communist free Mekong Delta by mid-1965, about one-third of all communist attacks in South Vietnam in 1966 occurred within the IV CTZ; Viet Cong forces controlled about 25% of the population of the Delta.
To the Vietnamese high command in 1966, the question of whether a province was “pacified” was entirely political. The American reality was that the South Vietnamese government-controlled, in total, only about four percent of the land in IV CTZ. ARVN commanders bragged that they controlled these areas but if true, it was only during hours of daylight; the Viet Cong controlled the night.
Riverine warfare is an extension of sea power. The Navy’s control of the sea enables it to project its strength ashore, including inland waterways, into the heart of the enemy territory. None of the Navy’s resources operate inside a vacuum; the Navy works as a team. In this example, blue water ships, amphibious forces, and its aviation arm all supported riverine operations. It was Vietnam’s communist insurgency within a vast inland waterway that led the Navy to reexamine its previous successes in riverine operations.
A key strategy in confronting and then defeating a guerrilla force is isolation and interdiction. US strategy in Vietnam involved denying guerrilla forces freedom of movement, access to the general population, the ability to withdraw into remote sanctuaries to regroup, and the ability to resupply. U. S. Naval forces in Vietnam played a key role in achieving all these objectives. Coastal surveillance programs formed a tight barrier against the infiltration of personnel, arms, and supplies from the sea. Taking surveillance one step further, the rigid control of fishing areas diminished the insurgent’s ability to feed himself, and river patrols established protocols for the inspection of junks and sampans, which were the primary method of transporting people and goods over hundreds of miles of inland waterways.
No less important in combatting guerrilla forces is gathering intelligence, which is often a slow, painstaking process. One must first locate the enemy before he can be eliminated. Finding the enemy was often facilitated by nurturing relationships with local inhabitants, which was also a key element in riverine operations.
Highly mobile and well-armed riverine forces coordinated their activities with ground and air forces to interdict guerrilla activities. The Navy’s shallow-draft patrol craft seized the initiative in carrying the fight to enemy sanctuaries far up the rivers and into canals —areas that had not been previously penetrated by French or ARVN ground units. To achieve these goals, the Navy employed a variety of combat and combat-support organizations, each with unique but well-coordinated missions: River Patrol Force, Mobile Riverine Force, Coastal Surveillance Force, Naval Advisory Group, and strike campaigns dubbed OPERATION SEALORDS.
An Imposing Environment
As previously explained, riverine operations assume many shapes because inland waterways form unique challenges. Vietnam’s inland waterways were at least a bewildering maze of interconnecting systems, so the Navy implemented a wide range of strategies to address them —made more difficult after the NVA began infiltrating South Vietnam in 1968. At that time, the US Navy began looking for more than increasingly dispirited guerillas; they were looking for hard-core NVA regulars, as well. The Mekong Delta was a paradise for guerrilla operations, which the NVA demonstrated could be just-as-easily implemented by regular forces. Thick vegetation along the waterways limits visibility and offers excellent opportunities for ambush; floating vegetation and heavily silted waters concealed mines and other explosive devices. Command detonated mines often signaled the beginning of hellacious firefights —some of these taking places within 50-75 feet of opposing forces.
There are three distinct regions within the Mekong Delta: Plains of Reeds, northwest of Saigon, which during seasonal floods lies beneath six feet of water, the Lower Mekong, which is a vast rice-growing region and the location of the imposing Ca Mau forest, and the mangrove swamps at the mouth of the Mekong adjacent to the Rung Sat (Forest of Assassins) Special Zone (RSSZ), which includes the main shipping channel to Saigon. In the mangrove swamps, tides are extreme and vegetation so thick that men on the ground lose sight of each other four feet apart.
On 26 February 1966, Viet Cong forces ambushed the SS Lorinda, a Panamanian-flagged coastal freighter on the Lòng Tàu River, about 18 miles south of Saigon. The attack wounded six crewmen and caused the ship to veer off course and run aground. This was not a trend the Americans could allow to develop. Accordingly, Commander, U. S. Military Assistance Command, Vietnam (COMUSMACV) ordered a punitive raid against insurgents operating within the shipping channel approach to Saigon.
Navy and Marine Corps operational planners put together a blue water force off the coast of Vietnam, the first major U. S. Navy riverine operation in the Rung Sat Special Zone (RSSZ); it marked a major turning point in the unfolding saga of projecting American sea power from the high seas and coastal waterways into the vast waterways of the Mekong Delta. Before this, the Navy’s participation in the river war was limited to inshore operations conducted by Swift Boats and Coastal Patrol Boats assigned to the Vietnamese Navy and their U. S. Navy advisors. From this point forward, the Navy became increasingly involved in the river war. The operation was designated JACKSTAY.
JACKSTAY underscored the versatility made possible by the domination of the wetlands, whether offshore or in-country. The operation, conducted in two phases, was planned to decimate the Viet Cong in the RSSZ, a 400-square mile area of swamp particularly suited for clandestine operations. The region of the RSSZ had harbored communist insurgents for well over a generation; it was where the Viet Minh/Cong manufactured weapons, where they treated their wounded, trained recruits, and stocked their supplies from North Vietnam.
JACKSTAY was a two-phased operation plan that called for an assault on the Long Thanh Peninsula (RSSZ) by the 1st Battalion, 5th Marines (1/5) from ships operating off-shore: the USS Princeton, USS Pickaway, USS Alamo, USS Belle Grove, and USS Merrick. USS Robison, GAME WARDEN swift boats, and MARKET TIME patrol boats provided naval gunfire support. Air groups from USS Hancock provided helicopter lift and close air support.
The operation kicked off on the morning of 26 March 1966 with preliminary naval bombardments by Robison and aircraft from Hancock. Navy Underwater Demolition Team (UDT) swimmers, preparatory airstrikes by Seventh Fleet carrier-based aircraft, and naval gunfire all supported the operation. Throughout, amphibious craft and coastal surveillance craft provided surveillance and blocking operations against Viet Cong escape. The long inland reach of U. S. Navy sea power quickly adapted to operational complexities.
A Marine rifle company landed via surface craft near Dong Hoa on the western end of the peninsula with two additional companies executing a vertical assault at the center and on the eastern end. The Marines encountered only scattered small arms resistance and soon established 21 four-man listening posts beyond their night perimeter. During the night, VC attacked one of these posts initiating a firefight that resulted in two Marine KIAs and three enemies dead. That same night, VC ambushed PCF-31 about one mile from Cần Giờ on the Long Thanh Peninsula, seriously injuring one crewman and severely damaging the patrol boat.
On 28 March, Marines made another unopposed surface assault on the Soài Rạp River, this time targeting an enemy logistics area on the Vam Sat River (linked to the headquarters element on the Soài Rạp River) and destroyed a cache of weapons that included over 1,000 grenades.
Following airstrikes from the Hancock and naval gunfire from USS Henry County, USS Washoe County, and Ontos fire from the deck of Henry County on 31 March, an 18-boat convoy entered the Vam Sat River. Led by two Vietnamese-manned Higgins Boats, the convoy included two Vietnamese LCCPs rigged with chain drags and grapnels for minesweeping, and armored LCM-6 (equipped with mortars and automatic weapons), seven LCMs, a rifle company of Marines in two LCVPs, two LCPLs providing additional gunfire support, two LCM-3 salvage boats. Helicopter gunships provided air cover. Commander Derwin T. Lamb, USN commanded the convoy from the open deck of an LCPL positioned directly behind the Vietnamese minesweepers. Captain John D. Westervelt, USN commanded the overall landing operation from an overhead helicopter.
As Lamb’s convoy approached the first bend of the Vam Sat River, Viet Cong command-detonated a crude electrical mine halfway between Lamb’s command LCP and the minesweepers. An explosion reminiscent of Confederate torpedoes from a hundred years before reverberated across the water. The craft escaped damage because they wisely hugged the shallows rather than navigating from the center of the channel. The explosion signaled the commencement of intense small arms fire from the thick foliage on both banks. Lamb led the convoy through the withering fire while all boats opened with their firepower. Helicopter gunships strafed and rocketed VC positions about 100-yards inland, preventing the VC from bringing heavier guns to bear. A mile further downriver, enemy fire became sporadic.
After landing a Marine rifle company in the heart of the dismal mangrove swamp, Lamb moved his convoy back up-river in the same formation to land two additional companies of Marines, who immediately disappeared into the thick underbrush. When the Marines had completed their mission, LCMs (also, “Mike” boats) churned their way to shore, crashing their way through the overhanging tree limbs and into the dense undergrowth. Lowering the ramps cut an opening through the rotted vegetation, making it easier for the Marines to re-board.
During recovery operations, the convoy again ran into ineffective small arms fire. The open LCMs, each carrying 60 Marines, may have been vulnerable targets were it not for the work of the gunships overhead and the fact that the VC riflemen were poor shooters.
JACKSTAY concluded on 6 April with the destruction of arms factories, training camps, a headquarters complex, and a makeshift hospital. Large amounts of rice and other foods were captured, along with 60,000 rounds of ammunition and 300 pounds of gunpowder. Sixty-three enemies were killed in the combined assaults, while American Marines lost five men killed in action. Subsequently, Viet Cong activity decreased in this area of the Delta.
The results of JACKSTAY were far more significant than the 53 confirmed Viet Cong dead or the tons of material destroyed or captured. Its success was laudable, of course, but so too was the projection of naval power into the heart of an enemy sanctuary. As the Navy’s initial combined riverine operation, JACKSTAY served as a loud knock on the door to an enemy that had had its way in the RSSZ for far too long. The message was unmistakable: the VC could run, and the enemy could hide, but they would not be able to elude the powerful arm of the United States Navy-Marine Corps team. Ultimately, after scurrying around like rats, the communists would only die tired.
In the middle of JACKSTAY, on 1 April 1966, Rear Admiral Norvell G. Ward, USN assumed duty as Commander, U. S. Navy Forces, Vietnam (COMUSNAVFORV). The purpose of NAVFORV was to consolidate several U. S. Navy programs under a single component command of the USMACV. In addition to supervision of the support commands at Saigon and Da Nang, and the Navy Construction (Seabee) battalions, Ward assumed responsibility for missions assigned to the Naval Advisory Group, Coastal Surveillance Forces, and River Patrol Forces. Mobile Riverine Force (TASK FORCE 117) was added in 1967.
- Sherwood, J. D. War in the Shallows: U. S. Navy Coastal and Riverine Warfare in Vietnam, 1965-1968. Washington, D. C.: Naval History and Heritage Command, Department of the Navy, 2015.
- Marolda, E. J. Riverine Warfare: The U. S. Navy’s Operations on Inland Waters. Washington, D. C.: U. S. Navy Historical Center, 2006
- Fulton, W. B. Vietnam Studies: Riverine Operations, 1966-1969. Washington, D. C.: Department of the Army, 1985.
- Affield, W. Muddy Jungle Rivers: A River Assault Boat’s Cox’n’s Memory of Vietnam. Hawthorne Petal Press, 2012.
- U. S. Army Field Manual 31-75: Riverine Warfare. Washington: Headquarters, U. S. Army, 1971
- Friedman, N. US Small Combatants: PT Boats, Subchasers, and the Brownwater Navy, an Illustrated Design History. 1987.
- Joiner, G. Lincoln’s Brown Water Navy: The Mississippi Squadron. Rowman & Littlefield, 2007.
- Rowlands, K. Riverine Warfare: Naval War College Review, Vol 71, No. 1. Art. 5., Annapolis: Naval War College, 2018
 Referred to as “White Mice” owing to their uniforms.
 SEALORDS was an acronym for Southeast Asia Lake, Ocean, River, and Delta Strategy. SEALORDS was a joint operational concept involving US and RVN forces conceived by Admiral Elmo Zumwalt who at the time served as Commander, Naval Forces, Vietnam (COMNAVFORV). Its intention was to disrupt enemy supply lines within and around the Mekong Delta. The program was turned over to the Republic of Vietnam Navy (RVNN) in 1971.
 Operational planners realized that the insurgent force within the RSSZ was too large for a single battalion operation, so the purpose of JACKSTAY was limited to disrupting Viet Cong operations and a demonstration to the enemy that the US was well aware of their presence and that US/RVN forces could penetrate their sanctuary at will.
 PCF-31 (Patrol Craft, Fast) (also, Swift Boat) were 50’ aluminum boats used in patrolling Vietnam’s extensive waterways, part of the so-called Brown Water Navy.
 Officially, Allis-Chalmers Rifle, Multiple 106mm Self-propelled M50 light armored tracked anti-tank vehicle with service between 1956-1969
 Designed by Andrew Higgins based on watercraft used for operating in swamps and marshes in Louisiana. Higgins produced nearly 24,000 of these boats, designated Landing Craft, Vehicle, Personnel (LCVP), during World War II. Variants of the Higgins Boats were created and designated for special purposes, such as LCU, LCI, LCA, and LCG.
 Admiral Ward was assigned to head the Naval Advisory Group, United States Military Assistance Command (Vietnam) on 31 July 1965. The Naval Advisory Group was dissolved and renamed U. S. Naval Force, Vietnam on 1 April and Admiral Ward became its first commander. During his assignment in Vietnam, Ward was instrumental in developing riverine and coastal interdiction strategies. Admiral Ward served in the submarine service for most of his career beginning in 1931. He retired from active duty in 1973, choosing not to accept a promotion to Vice Admiral to be with his cancer-stricken wife. Admiral Ward passed away in 2005.