About this Unit
Task Force 117, also known as the Mobile Riverine Force (MRF), was established in 1967 as a joint U.S. Army and Navy unit during the Vietnam War. Within this force, River Squadron 9 (RivRon 9) operated River Division 91 (RivDiv 91), conducting extensive riverine operations in the Mekong Delta. Their mission included transporting troops, providing fire support, and disrupting Viet Cong supply lines along the complex waterways. Through coordinated amphibious assaults and patrols, Riv Div 91 played a crucial role in the success of Task Force 117’s efforts to maintain control of critical river routes and bolster South Vietnamese security.
Historical Facts
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Unique Designation: Task Force 117 was officially known as the Mobile Riverine Force (MRF), a joint Army-Navy task force created during the Vietnam War to operate in the Mekong Delta’s complex river system.
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River Assault Squadrons: “Riv Sed 9” refers to River Assault Squadron 9, a component of the MRF, which fielded armored troop carriers, command boats, and other specialized riverine craft.
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River Division 91: “Riv Div 91” (River Division 91) was a sub-unit of River Assault Squadron 9, consisting primarily of Patrol Boat, River (PBR) or Armored Troop Carriers (ATCs), used for patrols, troop transport, and fire support.
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Innovative Tactics: Task Force 117 pioneered “brown-water” naval warfare, adapting US military doctrine to the unique challenges of Vietnam’s rivers, canals, and swamps.
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Joint Operations: The MRF was one of the first major US military units to integrate Army infantry and Navy riverine forces, conducting coordinated operations against Viet Cong strongholds.
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Major Engagements: Task Force 117 and its subunits played a key role in Operation CORONADO series (1967), a set of large-scale search and destroy missions aimed at disrupting enemy activities in the Mekong Delta.
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Living Conditions: Soldiers and sailors of Riv Sed 9 and Riv Div 91 often lived for weeks at a time aboard their vessels, facing heat, humidity, disease, and constant threat of ambush.
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Decorations and Honors: Task Force 117 units, including Riv Div 91, received numerous unit citations and individual awards for valor, including Navy Unit Commendations and Presidential Unit Citations.
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Casualties and Sacrifice: The riverine environment was extremely dangerous, with mines, ambushes, and snipers posing constant threats. Many MRF personnel were killed or wounded in action.
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Legacy: The innovative techniques, tactics, and equipment developed by Task Force 117 influenced later riverine and special operations doctrine, leaving a legacy still studied in modern military circles.
