Armored Troop Carriers (ATC), often called Tangos from the phonetic alphabet for T, were LCM-6 landing craft modified for riverine patrol missions.
They were used by the Mobile Riverine Force (MRF) of the United States Army and Navy in the Vietnam War. They were also used by Republic of Vietnam Navy (RVNN) and Khmer National Navy.
The initial Assault Support Patrol Boat (ASPB) were armed with two Mk 48 turrets with either 20 mm cannon or .50 cal machine guns, two single M60 machine guns or Mk 21 machine guns and one Mk 2 Mod 0/1 .50 cal machine gun/81mm mortar in a well in the aft of the boat, but this well was eliminated in later models.
The boat had a complement of five crewmen and could carry up to eight soldiers.