In the Vietnam War, the Mobile Riverine Force (MRF) (after May 1967), initially designated Mekong Delta Mobile Afloat Force, and later the Riverines, were a joint US Army and US Navy force that comprised a substantial part of the brown-water navy. It was modeled after lessons learned by the French experience in the First Indochina War of Dinassaut and had the task of both transport (of soldiers and equipment) and combat. The primary base was at Đồng Tâm Base Camp, with a floating base at the base of the Mekong River. It played a key role in the Tet Offensive. Concept of operations The Mekong Delta Mobile Afloat Force was originally conceived as providing an all weather "strike" capability in the Mekong Delta, to actively prosecute contact with Viet Cong units in the Vietnam War. A "strike" force was inherently and essentially different from the existing Navy interdiction and patrol forces (the River Patrol Boats of Operation Game Warden, and the coastal blockade of Operation Market Time). The Delta presented a classic venue appropriate to riverine operations such as had not been seen since the Union Navy in the (American Civil War) Mississippi Delta, and Sino-American operations in World War II. The Delta had a dearth of reliable roadways, all with predictable choke points at bridges, a literal myriad of creeks, streams, rivers, and canals, frequent monsoon conditions restricting air operations, and ground conditions that were often muddy. Historical experience A wide range of riverine craft were used by the allies, both before, and during the formalization of the US Navy Brown Water Navy, in 1964–1965. Foremost were the surplus World War II US naval craft; LCMs, LCVPs, LSMs, PGMs, LSSLs, etc., as well as post-war Nasty class patrol boats. One of the most popular riverine craft was the all-steel LCM converted into a naval Monitor, and was used by the French during the first Indochina war; and later by the US and South Vietnamese Navies. However, The French, during their war in Vietnam (1945–1954), had been heavily inspired by the US Navy LCVP, which they had received from the US, as part of the United States massive assistance program to fight communism. The French took the LCVP design and created an all new, and as it turned out, the only "original" or entirely new boat built for riverine warfare during the French Indochina war; the STCAN (a corruption of