The ubiquitous PT-76 reconnaissance vehicle was introduced in 1952 and whilst it resembles a tank in all conventional aspects: that is, it has a fully enclosed turret-mounted gun and is fully tracked, its role is not that of a battle tank, but is strictly for scouting. In the Soviet Army it was used solely in reconnaissance companies and battalions and not in the Ground Forces tank battalions.
A unique feature of the PT-76 (Amphibious Tank-76mm Gun) is that it is one of the very few fully amphibious tanks now in service in the world. The PT-76 was unusually large for a light tank of this period, due mainly to the buoyancy requirements for its swimming capability. The hydrojet system allowed the PT-76 to cross rivers whose stream speeds were no greater than about 8km/h. It had a water speed of about 10km/h. The engine was simply a T-54 engine sliced in half, with six cylinders instead of twelve. It is propelled through the water by drawing in water through ports at the rear of the hull sides, and ejecting it at the rear. Its large boxy hull provides a reasonable degree of buoyancy for use in rivers and lakes, but, unlike the US LVTP-7 series of troop carriers, it is not really intended for use in heavy surf.
The main turret armament is either the D-56T with a multi-baffle muzzle brake on early production models, or the D-56TM with a more conventional double-baffle brake on later types. Not surprisingly, the PT-76 is very lightly armoured, at no point exceeding 1/2in (14mm), and its side armour can be penetrated by shell fragments and even .50 calibre AP machine-gun rounds. PT-76s used in Vietnam were very vulnerable to air strikes. Nevertheless, it provided for a great deal of tactical mobility due to its excellent water crossing capabilities.
The basic chassis of the PT-76 has been used as the basis for a wide variety of other armoured vehicles, particularly armoured troop carriers such as the BTR-50 and indirectly it also spawned a later generation of light vehicles including the ZSU-23-4 Shilka air defence gun vehicle. The People's Republic of China produced a modified version of the PT-76 known as the T-60, which was fitted with a new turret, resembling a small scale T-54 turret, and armed with an 85mm gun. The hull was also redesigned to accommodate the greater weight of the new gun, but is similar in appearance.
Production of the PT-76 continued until 1967 by which time it was considered obsolete. It was a very large and conspicuous target and it was not well armed. A total of about 7,000 PT-76ís were built, of which about 2,000 were eventually exported. The P'I'-76 was a popular export item in the 1960s and 1970s, being cheap and easy to maintain.