Remembering the Vietnam War 50 Years Later: The U. S. Mobile Riverine Force Succeeds in Operations Coronado

Barely 20 years after the end of World War II, the United States found itself embroiled in a very different kind of conflict. In the jungles of Vietnam, American forces battled the North Vietnamese Army and their Allies, the Viet Cong, an unrelenting enemy with both regular army units and guerilla forces.  The Viet Cong used the natural geography of the country to their advantage, including the Mekong River Delta in southwestern Vietnam. This exceptionally difficult terrain presented operational challenges to the Americans and their South Vietnamese Allies.

Numerous distributaries of the Mekong River cut through the delta, which was heavily populated and vital in its production of rice and other essentials. Poor road infrastructure made overland communications and movement difficult. The South Vietnamese Army (SVA) attempted to protect this maze of marshy land, swamps,  canals, and rivers from the enemy. But with fragmented troops and artillery, the SVA’s defense of widely separated population centers was ineffective. By 1967 the American military, sensing an opportunity, had designed a unique organization known as the U. S. Mobile Riverine Force with the goal of seizing the initiative from the communist Viet Cong. 

Defined as joint Army-Navy operations  reliant on conventional ground support, riverine forces were designed to take advantage of the inland waterways. Special techniques and operating procedures by ground forces had to be supported by Naval ships and crafts directly from rivers and canals. While Riverine forces had played an important role in the American Civil War over 100 years prior, since then they had almost exclusively been used to facilitate river crossings in American combat.

American riverine forces faced an enemy seasoned in this kind of combat. The Viet Cong relied heavily on sampans and other small watercraft to move and resupply their forces. Given their knowledge of the waterways and the limited numbers of South Vietnamese military vessels, the Viet Cong had been largely unmolested in this area.

A key feature of the new concept was to be a multi-ship, mobile, floating base, capable of billeting several battalions of troops, relocating on short notice, and serving as a platform from which to launch amphibious and helicopter-borne assaults. In addition, a permanent base was to be dredged out of the river at Dong Tam, near My Tho.

2nd Brigade units trained to quickly board, debark from, and muster the support of river assault squadron vessels. Battle drills speedily delivered platoons, companies and battalions to selected sectors of river bank. Meanwhile, other Navy vessels assisted the South Vietnamese Navy in controlling river traffic in the operational area.

From June 1967 through March 1968 the Mobile Riverine Force launched eleven umbrella operations in the Mekong Delta, code named Coronado I-XI. These featured a sequence of constituent operations in duration from several days to several weeks. Initial assaults generally came by surprise over a river or canal bank in the early morning, supported by naval gunfire and artillery from barges. Subsequent forces often arrived by helicopter, heavily supported by helicopter gunships. In combined operations Vietnamese forces established blocking positions or joined the assault, often arriving by ground. Multiple threats from air, ground and water quickly removed the relative ease with which the Viet Cong had operated in the Mekong Delta.

The Viet Cong had given scant attention to defending river or canal banks, expecting assaults from the ground or air. For six months the Mobile Riverine Force enjoyed massive advantages over the Viet Cong in areas where previously they had operated freely. The Viet Cong eventually adapted, but the combination of ground, air and water assets left the initiative with the Americans. Their mobile afloat base and mobility assets enabled them to sustain operations by rotating units, avoiding excessive fatigue—or such hazards as immersion foot.

Prior to Operation Coronado XI, the North Vietnamese and Viet Cong launched the Tet Offensive on January 30, 1968. In these desperate circumstances the capabilities of the Mobile Riverine Force proved invaluable, speeding succor to isolated garrisons and repeatedly catching the now exposed Viet Cong at a tactical advantage. Government authority in the Mekong Delta soon resumed its pre-Tet posture.

The Mobile Riverine Force was a striking example of Army-Navy cooperation, innovation, and the synchronization of a wide variety of assets to achieve unique operational capabilities. The Mekong Delta was transformed from terra incognita to an area in which American forces routinely operated. In the period wherein the Mobile Riverine Force operated, the initiative rested with the Allies.

Recommended Reading

Cutler, Thomas J., “Brown Water, Black Berets”, Coastal and Riverine Warfare in Vietnam (Annapolis: Naval Institute Press, 2012)

Fulton, William B., Riverine Operations 1966-1969 (Washington DC: Department of the Army, 1973)