Task Force 117, Riv Sed 9, Riv Div 91

• 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. • 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. • 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. • 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. • 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. • 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. • 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. • 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. • 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. • 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.