The PT-76 is a Soviet amphibious light tank which was introduced in the early 1950 and soon became the standard reconnaissance tank of the Soviet Army and the other Warsaw Pact armed forces. It was widely exported to other friendly states, like India, Iraq, North Korea, and North Vietnam. Overall, some 25 countries use the PT-76.
The tank's full name is Floating Tank-76. 76 stands for the caliber of the main armament: the 76.2mm D-56T series rifled tank gun.
The PT-76 is used in the reconnaissance and fire-support roles. Its chassis served as the basis for a number of other vehicle designs, many of them amphibious, including the BTR-50 armored personnel carrier, the ZSU-23-4 self-propelled antiaircraft gun, the ASU-85 airborne self-propelled gun and the 2K12 kub anti-aircraft missile launch vehicle.
After WWII, the concept of light tanks was resurrected in the USSR. They were to be used in reconnaissance units and therefore an amphibious ability was essential. The requirements stated that the vehicle should be able to cross water obstacles with little preparation. Many prototypes of such light tanks were built in the late 1940s. The most successful was "Obyekt 740" designed by the engineer N. Shashmurin working at the VNII-100 institute in Leningrad. The vehicle was successful because it had a simple design, good navigational traits and a good cross country capability. At the time, its water-jet design was innovative. A prototype was built at Kirov Plant in 1950 and the tank was officially adopted on August 6, 1951 with the designation PT-76. Production started at the Stalingrad Tractor Factory. The tank was subsequently modified. In 1957 a gun D-56T was replaced with the D-56TM with a double baffle muzzle brake and fume extractor, the hull was raised 13 cm, and the tank was equipped with new vision and communications devices. First series were subsequently modified, receiving D-56TM guns and new equipment. in 1959, an improved variant, the PT-76B was adopted and remained in production until 1967.
DesignEditThe PT-76 has a typical tank layout: the steering compartment at the front, the combat compartment in the center and the engine compartment at the back. The tank has a three-man crew, with the commander also acting as the radio operator and gunner. This reduces his effectiveness as an observer. The commander and loader stations are located inside the turret, the commander sits on the left-hand side of the main gun and the loader sits on the right. They have a large oval-shaped double hatch that opens forward on top of the turret. The driver sits in the center of the front of the hull and has a one piece hatch that opens to the right, with three vision blocks and periscopes located beneath the main gun at the top of the sloping glacis plate. Under the driver's seat there is an emergency hatch which can be used by all crew members. At night the center periscope is swapped for a TVN-28 night vision device which gives the driver clear vision to 60 meters.
ArmamentEditIts main armament consists of a 76.2mm D-56T series rifled tank gun which has an effective range of approximately 1,500m and a rate of fire of six to eight rounds per minute. This gun is 42 cm long. The PT-76 carries 40 rounds for its gun. A typical ammunition load consists of 24 OF-350 Frag-HE, 4 AP-T and 8 BK-350M HEAT rounds. The gun is mounted in an oval dish-type circular truncated cone turret with flat sloping sides which is mounted over the second, third, and fourth pair of road wheels. All PT-76s have a fume extractor for the main gun at the rear of the turret.
The 7.62mm SGMT coaxial machine gun comes with 1,000 rounds. This weapon has a maximum effective range of 1,000m in daylight while the vehicle is stationary, 400 to 500m in daylight while the vehicle is on the move and 600m at night. Maximum range is 1,500m. It can be fired in 2 to 10 round bursts and has a practical rate of fire of 250 rounds per minute and a cyclic fire rate of 650 rpm. From 1967 the machine gun was replaced by a PKT machine gun of the same caliber.The main gun is considered light for a modern tank which can fire BM-354P HVAP, sub-caliber AP-T, BR-350 API-T and OF-350 Frag-HE rounds and is capable of penetrating the armor of APCs and other lightly armored vehicles.
The commander/gunner has a cupola on the left side of the double hatch. The cupola has the TPKU-2K observation device and two TNP day periscopes and can be rotated 360 degrees by hand. The commander also has a 4x optical sight mounted to the left of the main armament and a TShK-66 sight/rangefinder. The loader has the MK-4 observation device mounted on the turret's roof in front of the hatch.
CountermeasuresEditThe armor of the PT-76 consists of homogenous, cold rolled, welded steel. Its turret has 20mm at 35 degrees at the front, 16mm at 35 degrees at the sides, 11mm at the rear, and 8mm on top of the turret. The hull is made up of: 10mm at the upper front, 13mm at the lower front, 14mm at the sides, 7mm at the rear and 5mm underneath. This gives it protection against 7.62mm small arms fire and small artillery shell fragments. It does not protect against 12.7mm of .50 caliber heavy machine gun fire or larger shell fragments.
TacticalEditThe torsion bar suspension consists of six evenly spaced large rubber-tired road wheels with the drive sprockets at the rear and the idler in the front. The road wheels are hollow to minimize weight. These hollow road wheels increase the tank's buoyancy by 30%. There are no track-return rollers. The first and last road wheels have a hydraulic shock absorber and the steel tracks have 96 links each when new, each link has a single pin. There is a small, thin, horizontal skirt over each track. Its V-6 6-cylinder 4-stroke in line water cooled diesel engine develops 240 hp at 1,800 rpm which gives it a road speed of 44 km/h and a range of 370 km-400 km. The vehicle can cross 1.1m high vertical obstacles and 2.8m wide trenches and climb 52 degree gradients. The engine has a cooling system and an initial heater. The PT-76 has a 5-speed manual shaft-type transmission system similar to the one in the T-34/85. The gearbox has four forward gears and one reverse. The vehicle has a side clutch that enables it to make turns and a handbrake. The tank has four mounts for additional fuel tanks at the rear of the hull. The two on the corners are for flat type external tanks and the two in the center are for a drum type. These additional tanks increase the range from 370 km-400 km to 480 km-510 km. The PT-76 is a reliable, simple to operate and highly mobile reconnaissance vehicle and is ideally designed for amphibious operations, but it has many limitations as a fighting vehicle.
StrategicEditThe PT-76 is amphibious, it has a flat, boat-shaped hull which is hermetical and ensures minimal resistance when the tank is afloat. It can swim after switching on the two electric bilge pumps, erecting the trim vane which improves the vehicle's stability and displacement in the water and prevents water from flooding into the bow of the tank. Switching the driver's periscope for a swimming periscope enables the driver to see over the trim vane. When not in use, the trim vane is stowed in the front of the bow over the barrel of the main gun and serves as additional armor. Bilge pumps keep the tank afloat even if it leaks or is damaged. There is a manual bilge pump for emergency use. The tank is propelled through the water by two hydrojets, one on each side of the hull, with the inlets underneath the hull and the outlets at the rear. There are additional asistant water-jet inlets on both sides of the hull over the last roadwheels. The rear outlets have lids that can be fully or partially closed, redirecting the water stream to the forward-directed outlets at the sides of the hull, thus enabling the vehicle to turn or go in reverse. To turn to the left for example the left water-jet is covered, to turn to the right, the right water-jet is covered. To make a 180 degree turn, one water-jet sucks in water while the other pushes it out. This system was designed by N. Konowalow. It is the same system as the one used in the BTR-50 APC which was based on the PT-76. The tank can swim up to 10.2 km/h and has a range of 100 km. It can cross most water obstacles and can also swim in the sea. However, its amphibious design makes it disproportionally large for a vehicle of its weight and allows less armor protection than other light tanks.
The PT-76 is equipped with a tank communication device, a gyro compass, a 10-RT-26E radio and has an antenna for it , which extends itself when needed. It also has two headlights in front of the hull and a searchlight on the right-hand side of the top of the turret It lagged behind other Soviet armored fighting vehicles because only the driver had a night vision device and also because it had no fire or NBC systems which significantly reduced its effectiveness. The lack of NBC protection ended with the PT-76B which has the PAZ NBC system. Because only the driver has night vision equipment, the crew has a vision range of 4,000m by day and 600m by night.
Service historyEditThe PT-76 is used/stationed in/by the following Russian units/bases: 61st Tank Repair Plant, 61st Kirkinesskaya Marine Brigade from Sputnik which is part of the Murmansk military district, 175th Marine Brigade from Tumannyy which is part of the Murmansk military district and 336th Belostokskaya Marine Brigade from Baltyysk which is part of the Kaliningrad military district.
In Ludowe Wojsko Polskie (LWP), PT-76s and PT-76Bs were used by the reconnaissance subunits of tank divisions and mechanized divisions and Coastal Defense Units including the 7th Lusatian Landing Division. Poland also operated FROG-5 "Luna" tactical missile launch vehicles.
PT-76s were in service with the Indian Army and they were in reserve status before they were withdrawn from service in 2009 after which they were used for target practice by the army and as static memorials at various military facilities.
VietnamEditPT-76s along with T-54s and T-55s, Type 59s and Type 62 tanks formed the bulk of the NVA armored forces.
The first successful action of NVA armor was against the Lang Vei Special Forces camp on 6/7 Feb. 1968. Thirteen PT-76s, of the NVA 202nd Armored Regiment spearheaded an assault against approximately 24 Green Berets and 500 irregulars. The defenders fought back with their 106mm M40 recoilless rifles, and ineffectively with M72 LAWs. They requested support from nearby Khe Sanh, which was unable to help, as it too was under siege. The Lang Vei camp was overrun, with the PT-76 using their turret-mounted searchlight to machine gun any irregulars who panicked and ran out of the underground bunkers. A few survivors broke out and were airlifted to safety.
The first tank-to-tank engagement occured in mid 1968 when a US reconnaissance airplane observed a PT-76 being washed by its crew in the Ben Hai river in the DMZ. The Forward Air Control pilot radioned the tank's position to a nearby M48 Patton tank unit of the US 3rd Marine Tank Battalion. With the FAC adjusting fire, the Patton fired three 90mm rounds, obtaining a hit with the third round. The tank crew abandoned their vehicle. Shortly afterward, some returning F-4 Phantom jet fighter bombers, with ordnance to expend, observed the PT-76 and bombed the remainder of the vehicle.
Battle of Ben HetEditOf the US Army's three armor (tank) battalions in Vietnam, only the 1/69th engaged in a tank to tank duel. On March 3, 1969, the Special Forces camp at Ben Het was attacked by the NVA 202nd Armored Regiment. The 202nd was given the task of destroying the camp's 175mm self-propelled guns. One of the PT-76s had detonated a land mine, which not only alerted the camp, but also lit up the other PT-76s attacking the firebase. Flares had been sent up, thus exposing adversary tanks, but sighting in on muzzle flashes, one PT-76 scored a direct hit on the turret of an M48, killing two Patton crewmen and wounding two more. A second Patton, using the same technique, destroyed a PT-76 with their second shot. At daybreak, the battlefield revealsed the wreckage of two PT-76s and one BTR-50 armored personnel carrier.
First combat use of the TOW missileEdit
On 9 May 1972, a PT-76 unwilliingly participated in changing the story of armored warfare. On 24 April 1972, a US special experimental UH-1B helicopter team, consisting of two helicopters mounting the new XM26 TOW anti-tank missile (Tube Launched, Optically Tracked, Wire Guided), accompanied by technicians from Bell Helicopter and the Hughes Aircraft Corporation arrived in Vietnam. The team, labeled the 1st Combat Aerial TOW Team was deployed in the Central Highlands of Vietnam, where it commenced gunnery training. From May 2, the team made daily flights in search of enemy armor. On 9 May, NVA armored units attacked the Ranger camp at Ben Het; the TOW team destroyed 3 PT-76s and broke up the attack.
On 26 May, the North Vietnamese Army made another attempt to retake the city of Kontum. TOW aircraft were brought in at first light and found NVA tanks moving almost at will through portions of the city. Conventional airstrkies would have been risky for friendly forces, and the TOW proved to be ideal for picking off enemy tanks. At the end of the first day, the two TOW helicopters had destroyed 9 tanks and damaged one more. Five of the destroyed tanks were T-54/55s, and the remaining four destroyed and one damaged were PT-76s. By the end of the month, TOW missiles launched from helicopters had 47 confirmed kills, of which 24 were tanks.
Other combatEditThe PT-76 saw action with Indian forces in the Indo-Pakistani War of 1965 and 1971. Despite being obsolete by 1971, the superior tactics and overwhelming numbers of the Indian Army enabled the PT-76 to play a vital role in defeating the Pakistani Army. In the Eastern theater the high numbers of PT-76s proved superor to the Pakistani WWII-era M24 Chaffee light tanks. It was different in the Western theater, where they proved incapable of facing Pakistani M48 Patton and Type 59 main battle tanks, especially at the crucial Battle of Chamb.
The PT-76 also saw service in the Six Day War during which the Israeli army destroyed or captured about 200 Egyptian T-54, T-55 and PT-76 tanks. During the Yom Kippur War in 1973, PT-76s were used during the crossing of the Great Bitter Lake by the Egypian 135th Marines Brigade.
It saw some service in the Angolan Civil War.
During the Yugoslav wars, the PT-76 served with the Yugoslav People's Army and later the army of the Krajina Serbs in a few battles during the Ten-Day War in Slovenia and Croatian War of Independence.
The Indonesian Navy used its PT-76Bs on the Indonesian island of Ambon during civil unrest from 2000 onwards.