The PT-76 [PT = Plavayushtshiy Tank - Amphibious Tank] is one of several light amphibious tanks developed and used by the Soviet Army. The vehicle entered service in 1954 and is amphibious without additional preparation. Although the PT-76 is lightly armored and undergunned for a modern tank, its inherent amphibious capability outweighs these limitations. It has had widespread use in the Warsaw Pact and many other countries. ThePT-76 carries a 76mm main gun with a maximum effective range of approximately 1500 meters. Operated by a three man crew, the PT-76 is often used to transport troops.
Introduced by the Soviet Army in 1952, the PT-76 light tank is very lightly armored, with a large hull because of the volume required to maintain its buoyancy. Two water jets at the rear propel the vehicle during amphibious operations, which only require that a trim vane be erected at the front of the hull and that the hull bilge pumps be turned on before entering the water. Opening and closing the water jet ports on either side allow the vehicle to change direction while afloat. The crew of three includes a driver in the hull center front, and a loader and vehicle commander in the turret, where the TC also acts as gunner. The 76mm main gun dates back to the early T-34 cannon of WWII, but similar tanks built in China utilized a different turret and mount 85mm guns. The tank has been employed by the Soviet Army and marines and about 25 other countries.
The PT-76 is a lightly armored amphibious tank with a flat, boat-like hull. The suspension has six road wheels and no return rollers. A dish-type turret is mounted over the second, third, and fourth road wheels, with a double hatch for commander and loader. The driver's hatch is located beneath the main gun, at the top of the sloping glacis plate.
The PT-76 was formerly the standard reconnaissance tank of the Soviet and Warsaw Pact armies. Although it has been replaced in first-line units by BMP-1 and BMP M1976 vehicles, it may still be found in the reconnaissance companies and battalions of some motorized rifle and tank regiments and divisions, as well as in naval infantry units. Aside from its reconnaissance role, it is also used for crossing water obstacles in the first wave of an attack and for artillery support during the establishment of a beachhead. Its V-6 240 hp water-cooled engine gives it a road speed of 44 km/hr with a cruising range of 260 km, and a twin waterjet propulsion system moves it through water at 10 km/hr with a range of 100 km. The 76-mm main gun, considered light for a modern tank, fires HVAP and HEAT rounds capable of penetrating APCs and other light armored vehicles. The PT-76 is a reliable, highly mobile reconnaissance vehicle and has ideal design for amphibious capability, but it has many limitations as a fighting vehicle.
Like most Soviet tanks, the PT-76 has limited ability to depress its main gun, and therefore cannot fire effectively from defilade. Its amphibious design makes it unnecessarily large for its weight class and allows less armor protection than in other light tanks. Because of its relatively thin armor (maximum thickness 14 mm in the hull, 17 mm in the turret), it is vulnerable to artillery fragments and .50 caliber machine gun fire. The fact that the commander is also the gunner and radio operator reduces his effectiveness as an observer. The PT-76 also lagged behind other Soviet armored fighting vehicles in having no night vision equipment and no NBC protection system for the three-man crew.
While still useful as a patrol vehicle some fifty years after its introduction, the PT-76’s heyday was at the peak of the Cold War. It saw action during the Vietnam and Arab-Israeli Wars, but it was during the 1971 India-Pakistani conflict that the PT-76 came closest to being employed as the Soviets had foreseen.
The Indian 7th Light Cavalry was the first Indian Army unit to receive PT-76s, in late August 1965. The 7th had turned in ancient Stuart M-3 light tanks. By the beginning of September, conversion training for the crews had started, supervised by three regimental officers who had been taught in the Soviet Union. Without enough familiarization and without properly boresighted main guns, the Indians went to war. The sudden introduction of the new tank also caused considerable confusion among other Indian units that had not even seen the PT-76 and mistook them for Patton tanks. After the 1965 conflict, the Indian army stationed two PT-76 regiments and two armored car squadrons under XXXIII Corps control in the Nagaland- Mozoram area for COIN operations.
For the invasion of East Pakistan that began on 4 December 1971, the Indian Army had hoped to use their PT-76s. The Indian II Corps had the 45th Cavalry and ‘B’ Squadron, 63rd Cavalry. XXXIII Corps had the rest of the 63rd, along with the 69th Armored Regiment. The 63rd had T-55s, while both the 45th and 69th had PT-76s. This combination would prove extremely useful in overwhelming the Pakistani defenses.
While Pakistan's M24 obsolete 75mm made short work of the PT-76, the Pakistani 106mm RCL HEAT rounds didn’t cause the havoc that might have been expected, probably due to poor Pakistani handling. There were also rumors that these guns were delivered without manuals. Another factor was that the war was fought in the era before wide-spread Pakistani issue of the RPG-7. While Pakistan had U.S.-made 3.5-inch M20 bazookas, these appeared to have not been used much.
The Indian PT-76s were usually deployed in squadron strength (the Pakistanis were usually deployed only by troops of three) and engaged targets at ranges under 1,000m. Pakistan's M24 Chaffee gun tubes were worn out, so that accuracy beyond 1,000 meters was impossible. The 106mm recoilless rifle’s maximum range against stationary targets at the time was 800m, the M20 bazooka under 300.
The Indian Army’s repeated use of their amphibious capability allowed them to bypass soft ground and water obstacles that would have checkmated T-55-equipped armor units. Even in 1971, the PT-76 was approaching technological obsolescence but, “In the land of the blind, the one-eyed man is king."
Four variants are distinguished by differences in the 76-mm main armament. Early models mounted a D-56T gun with no bore evacuator and a long, multi-slotted muzzle brake. Later models mount a D-56TM gun with a bore evacuator and a double-baffle muzzle brake. There are further variants with a stabilized D-56TM gun (PT-76B) and with an unidentified clean-barrel gun. A coaxial 7.62-mm machine gun is also mounted at the right of the main gun. The original PT-76 was produced in limited numbers with a non-stabilized main gun. Some PT-76s are augmented with 12.7-mm AA MGs.
- Polish PT-76: Variant with a separate commander's hatch and 12.7-mm MG.
- Type 60: Chinese variant, very similar.
- Type 63: Chinese variant with a new turret, 85-mm gun, and 12.7-mm AA MG.
- Israel offers an upgrade package with a 90-mm gun, LRF fire control and a 300-hp engine.
The popular PT-76 chassis has been modified for use in many subsequently developed vehicles, including the BTR-50P and OT-62 series of APCs, the ZSU-23-4 self-propelled antiaircraft gun, the ASU-85 airborne assault gun, the transport-launching vehicles for the FROG-2 through FROG-5 and SA-6/GAINFUL missiles, and even the BMP which replaced the PT-76 in Soviet reconnaissance units.
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