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Cold War Soviet Light Tanks

PT-76

USSR (1952-1967)
Amphibious Light Tank – circa 12,000 built

The PT-76 is a Soviet amphibious light tank designed in 1948 which saw service from 1952 up until its gradual retirement from 1967 onwards, partly replaced by the more versatile BMP-1 APC. Characterized by a wide hull and water jet propulsion, the PT-76 offered excellent amphibious capabilities. It was, however, plagued by a large silhouette, weak armor protection, and an underpowered 76 mm gun. Despite these flaws, the PT-76 enjoyed a long service life within the Soviet and Russian armed forces, which only placed it into its reserves in 2006. Comparable to other Soviet Cold War vehicles, it has seen combat in several wars and is still in use within smaller armies. Russia is attempting to replace them with BMP-3F amphibious IFVs.

A new war in Europe

During the Second World War, the Soviet amphibious light tanks left much to be desired. The T-37A and T-38 light tanks, armed only with machine guns, were useless against German Panzers, while the T-40 light tank, being inadequately armed, simply reinforced the failure of the earlier vehicles. Nonetheless, the end of the war left a state of tension between the USSR and western nations. It was very likely that central Europe would become a battlefield between the two superpowers. However, the geography of this area is problematic for tanks. Riddled with forests, rivers, and marshes, heavy and medium tanks would require mobile bridges and other logistic systems to cross obstacles. The Soviets knew what to expect of warfare in Europe. Namely, water obstacles up to 100 m every 35-60 km, 100-300 m every 250-300 km and over 300 m wide every 250-300 kmThe solution was to have a mobile and nimble light tank that could be amphibious. These tanks were to penetrate into enemy territory and scout the environment until the heavier tanks came. Learning from previous mistakes, this new amphibious tank had to be equipped with a powerful gun to make it more useful against enemy armor. Thus the PT-76 was born, having excellent buoyancy to allow it to cross those water obstacles.

Development

Right after the Second World War, when the new geopolitical and military climate became apparent, the USSR still had large amounts of obsolete light tanks, such as the T-60 and T-70, many of whom were in poor condition. Some of these simply ended up being dismantled to be used for spare parts in SU-76 tank destroyers and GAZ-AA trucks, while the majority were scrapped. This left the Soviet army effectively without light tanks. Initially, in 1946, many heads of the tank industry, ministers, and engineers disliked the idea of an amphibious light tank (and light tanks in general), as the development and propelling of an amphibious vehicle would add unnecessary cost, while the buoyancy requirement meant that the armor had to be extremely thin. They also believed that the small advantage gained in mobility over medium and heavy tanks was not justifiable considering the large sacrifice of armor and firepower.

However, in January of 1947, the headquarters of the USSR Naval Forces addressed the Main Operations Directorate of the Armed Forces about the creation of two amphibious vehicles: an APC and a light tank. Interestingly, they wanted the light tank to have a performance similar to that of the T-34-85. It was to weigh 20 tonnes (22 US tons), have an 85 mm gun, and a 400 hp engine. These requirements were eventually dropped, as the weight was lowered to 15 tonnes (16.5 US tons). The vehicles were to share the same platform, which could be used later for developing other vehicles.

Thus, in March of 1947, recognizing the geographic situation in central Europe, the commander of the Group of Soviet Occupation Forces in Germany (GOSVG) was interested in the revival of amphibious light tanks. A war in central Europe would be based on mobility and speed. A fast and amphibious light tank could advance quickly, conducting flanking maneuvers, surprise attacks, and more, something medium and heavy tanks could not. It was also added that light tanks could be air-transportable and that they would be crucial in wars in the Middle East, where the lack of infrastructure would be even more problematic for medium and heavy tanks. Even in the Far East, where railways and good road networks were absent, a light tank capable of driving under its own power was the best choice. As the threat of the use of tactical nuclear weapons became more serious, it was also envisioned that fighting in such conditions would be best done by light tanks, as they could move quickly and have low maintenance costs.

Object 101/R-39

As light tanks seemed more favorable, in 1947, at the Red/Krasnoye Sormovo No.112 factory, testing was done on various light tanks and APC, one of which was the PT-20. These were deemed unsuccessful for various reasons, the main being that these prototypes required aluminum boxes filled with air for floatation. In other words, the vehicle needed prior preparation for floating. In addition, the flotation devices had to be carried in trucks. This severely harmed the logistics and the agility of the tank. Ideally, and rather obviously, the vehicle would be able to float on its own without additional preparation.

As a result, on the 10th of June, 1948, the No.112 factory was tasked with redesigning the light tank and the APC to be ready for amphibious operations without any prior preparation. For the light tank, the specifications were the following:

The combat-ready weight should be below 15 tonnes (33,000 lbs.), the engine needed to deliver 300 hp (211 kW) and had to be able to allow the tank to reach speeds of up to 50 km/h (31 mph) on-road and 12 to 14 km/h (7 to 9 mph) in water. In addition, both the light tank and APC should be able to carry 2,000 kg (4400 lbs.) on top. The light tank had to be equipped with a 76.2 mm gun.

The designs were ready by July 1948 and were presented to the GABTU (Main Directorate of Armoured Forces) with promising feedback. On the 16th of July of the same year, the Ministry of Transport Engineering ordered the No.112 factory to produce two prototypes and test them by June 1949. These vehicles were given the name ‘Object 101’ (R-39) for the light tank and ‘Object 102’ (BTR R-40) for the APC. The first R-39 prototype was built between April and May 1949 and by the 27th of May, testing began. It was found that the center of gravity was a bit too far back, causing problems in water.

The second prototype was ready by June of the same year, with the turret moved forwards by 240 mm (9.4 inches). These prototypes, however, failed the factory tests – the reliability and strength of certain components were poor, and the vehicles did not even reach the desired speed on water (7 km/h out of the 10 to 12 km/h desired). On the second prototype, to fix the slow speed, the propellers were mounted externally and were supposed to be lifted onto the engine deck when not used. However, this left them vulnerable to enemy fire and overall damage. The second round of testing was done at VNII-100 institute, in Leningrad, but they failed those too. The poor performances led to the Sormovo No.112 factory being removed from the program. After this disappointment (the program was supervised by Stalin himself), some of the heads of No.112 factory alongside certain engineers, were removed from their offices and held accountable (it is unclear if this means simply losing their functions, or worse).

R-39 prototype at the Krasnoye Sormovo No.112 factory in Nizhny Novgorod. The prototype, rather similar in design to what the PT-76 would look like, was poorly built and failed miserably during tests.
Source: Rulit.me
Rearview of the R-39, also called the Object 101 (not to be confused with SU-101) during testing.
Source: PT-76 amphibious tank, Mikhail Borisovich Baryatinsky
R-39 while swimming. Note the open wave deflector.
Source: PT-76 amphibious tank, Mikhail Borisovich Baryatinsky
R-39 after amphibious testing, 1949.
Source: PT-76 amphibious tank, Mikhail Borisovich Baryatinsky

The Council of Ministers of the USSR decided on the 15th of August of 1949 that the VNII-100 research institute in Leningrad should restart the development of the two vehicles, with testing to be started in 1950.

Object 270 & Object 740

The remaining researchers and workers from Krasnoye Sormovo and VNII-100 came to ChKZ (Chelyabinsk tractor plant) to continue work on the 15th of August, 1949. The blueprints were ready by the 1st of September. Two different sets of drawings were made, one set by Grigory Moskvin and A. Sterkin, named ‘Object 270’, and drawings made by L. Troyanov and Nikolai Shashmurin, named ‘Object 740’. The latter made ‘Object 750’ as well, which was the APC version. To fix the problems encountered on the initial R-39, engineers came up with four different solutions. These were: propellers in water tunnels, conventionally mounted propellers on hinges, water jets, and lastly, tracked propulsion. Engineers Kotin and L.Troyanov wanted to implement hinged propellers, as they had worked on vehicles with this propulsion system before. Shashmurin, however, wanted to implement water jets designed by Nikolai Konowalow. Shashmurin went to the Minister of Medium Machine building, Viacheslav Malyshev, to get his idea materialized. Malyshev agreed, terminating all other projects for propulsion systems and placing efforts entirely on a vehicle with two waterjet engines, the Object 740. Plans in 1:20th scale were drawn on 15th November 1949, and the first Object 740 prototype was completed in February of 1950.

Object 740 from the front. One of the largest differences between it and the production PT-76 was the curved, boat-shaped hull sides and clear stamped wheels.
Source: m.blog.naver.com
Object 740 during testing in Polotsk, 1950. Note the open ports at the rear on both sides for the integrated waterjets.
Source: m.blog.naver.com
Object 740, Polotsk, modern-day Belarus, 1950. Note that the water jet covers are in place.
Source: m.blog.naver.com

Testing was done on the Object 740 from the 15th of May, and the vehicle passed them by August. After the initial bugs and issues were fixed on the prototypes, it was deemed suitable for adoption in the Soviet military. The decree of the USSR Council of Ministers on the 23rd of November, 1950, assigned the first 10 vehicles to be produced at Stalingrad Tractor Plant (STZ), for which a specialised construction bureau was made, headed by M. M. Romanov. The first 10 units were manufactured between May and June of 1950. These were sent to the Soviet military for active trials with troops, during which refinements and final touches were made. On the decree of USSR Council of Ministers, 6th of August, 1952, the Object 740 was adopted into service under the name PT-76, плавающий танк (Romanized: plavayushchiy tank) meaning floating tank 76, from the 76 mm gun. It was first unveiled to the public on Victory day, 9th of May, 1952. The tank was mass-produced at STZ, later renamed VgTZ (Volgograd Tractor Plant).

Interesting to add are the Object 728 and Object 270-M (built by VNII-100). These were testbeds for the new water-jet engines. This was the first time the Soviet Union made a tank using water-jets. The Object 728 had a weight of 14 tonnes (30,900 lbs) to simulate the Object 740 in water.

Object 270-M testbed.
Source: PT-76 amphibious tank, Mikhail Borisovich Baryatinsky
Object 728 testbed at VNII-100, Leningrad. The large tower on top was placed there in case the testbed sank. Note the T-34 wheels.
Rear view of Object 728. Noteworthy are the large waterjet outlets in the rear.
Chart showing the PT-76 complex development and its ‘relatives’.
Source: Solyankin-Pavlov-Pavlov-Zheltov

Unsuccessful rival – K-90

The Object 740 did, in fact, have a competitor, in the form of the K-90. The K-90 was developed at VRZ No.2 Plant in Moscow, under A. F. Kravtsev. He was well aware of the complexities and price of designing such a vehicle from scratch, so he wanted to use automotive parts, as well as parts from decommissioned materiel, such as the Ya-12 tractor, T-60, and T-70 light tanks from the war. The K-90 was smaller and simpler, having a boat shaped hull for buoyancy and two propellers with individual rudders for water steering. Like the PT-76, it too was armed with a 76 mm cannon inside a rounded turret. However, it was rather slow both on land (43 km/h) and water (9.6 km/h), and after trials, it was eventually rejected in favour of the Object 740. The Moscow plant also designed the K-75 and K-78, meant to compete with the Object 750 APC, but small size and poor mobility plagued the developments as well, and were never adopted.

K-90 amphibious light tank in Patriot park, Moscow. Note the welded boat-like hull and T-60 wheels.
Source: Vitaly Kuzmin

Usage & Tactics

PT-76 tanks were assigned to amphibious companies and reconnaissance companies of tank and motorised rifle regiments. They had dedicated roles within the regiment, such as securing river banks, allowing for the other tanks, troops and equipment to cross the water obstacle with conventional river-crossing equipment, which took a lot longer.

When used in reconnaissance missions, they would move ahead of the regiment, securing areas, scouting for enemy positions, but also – if attacked, fulfilling the duties of medium tanks, which were not present.

The Soviet Naval Infantry (Morskaya Pekhota) was revived in 1963 as a subordinate of the Soviet Naval Forces, with three regiments; Northern, Baltic, and Black Sea. These were equipped as a mixed armor force, with PT-76 and T-55 tanks. Here, the PT-76 tanks were used as assault tanks in water areas, such as beaches and riverbanks, providing armored support and firepower to marine infantry battalions. The only Naval Infantry division in the Pacific also added a mixed PT-76/T-55 regiment, in addition to its existing tank regiments.

PT-76 tanks of the Naval Infantry landing on a beach in a military exercise. They would be transported close to the shore with landing ships, like the Ropucha-class, pictured above.
Source: (bastion-karpenko.ru)

Layout & Design

The PT-76 was a revolutionary tank for the Soviet Union, yet its basis was very simple. The wide and long hull allowed for excellent buoyancy in water, but it had to sacrifice the armor, with the thickest part being only 15 mm (0.6 inches) on the front of the turret. The engine was placed in the rear, behind the turret. The hull itself was divided into two sections, engine and jets in the rear and fighting compartiment in the front. These were separated by a metal bulkhead. The water jets, two on each side, had an inlet in the floor of the hull and the exit hole in the rear. Two smaller ports on the side were used for propulsion in reverse. The turret had a low profile and had both the commander (who was also the gunner) and the loader. It housed the D-56T 76.2 mm gun (in 1957, this was replaced with a D-56TM). The main engine was named the V6, but was a 6 cylinder in-line, 4-stroke, water-cooled diesel capable of outputting 240 hp (179 kW) at 1,800 rpm. This gave the 14 tonne (32,000 lbs.) tank a power to weight ratio of 16.4 hp (12.1 kW) per tonne, and allowed it to reach a top speed of 44 km/h (27 mph) on roads.

Cutout of a PT-76 model 1957 (often referred as PT-76B in western literature).
Source: m.blog.naver.com

Despite being used as a reconnaissance tank on many occasions, the PT-76 was not designed with this in mind. It was never equipped with any proper equipment for such tasks, and, probably one of the most significant drawbacks of the PT-76 was its poor visibility. With a grand total of 11 periscopes, excluding the sight of the main gun, the PT-76 was behind many Soviet tanks of the time. As an example, the T-10 heavy tank had double the amount of vision ports and periscopes. This begs the question why was the PT-76 used in reconnaissance roles but the answer is deceptively simple. Soviet doctrine in the 1930s saw amphibious tanks, like the T-37A, as primarily for reconnaissance purposes. They were light and small, and their poor armament did not allow for any other tasks to be performed well. The PT-76, however, was much larger than a T-54 and was rather underpowered. Yet the PT-76 was, in fact, used in such missions because it was the only amphibious light tank in the Soviet arsenal. In this sense, it could be considered that the tank design had outpaced an older doctrine of use for tanks in the absence of dedicated reconnaissance vehicles.

The weight was distributed amongst the components was as following:
Armored Hull: 4,942 kg (34.6%*)
Turret: 751 kg (5.26%*)
Armament: 1,111 kg (7.78%*)
Powerplant: 1,307 kg (9.15%*)
Transmission: 1,548 kg (10.8%*)
Chassis: 2,548 (17.8%*)
*; % of total mass

The remaining 2 tonnes (15%) was ammunition, fuel, equipment, etc.

Russian chart comparing Soviet and Western tanks. The hull of the PT-76 appears massive compared to the T-54 and rivaling light tanks, like the AMX-13 and M41 Walker Bulldog.
Source: thesovietarmourblog.blogspot.com

Crew positions

The light tank had a crew of three: a driver, a loader, and a commander that also operated the gun. The driver was placed centrally in the hull, beneath the gun. The commander sat on the left side of the gun, in the turret, while the loader was on the other side, to the right of the turret. The turret ring of the PT-76 was very large, at a diameter of 1,800 mm (6 feet). For reference, the T-34-85’s turret ring had a diameter of 1,600 mm, and T-55, 1,850 mm. Compared to contemporary Soviet tanks, the large turret ring combined with one less crew member and a smaller-caliber gun meant the PT-76 had some of the best ergonomics of its time in the USSR.

Driver

The driver, as mentioned before, sat inside the hull and had three periscopes for vision. Despite the rather good visibility given by the three periscopes, he still relied on commands from the turret. The central periscope could be mechanically lifted up to improve vision when driving through water. The driving position was rather interesting, as the pedals were located on the angled front hull, while the seat was mounted on the hull floor. This meant that his feet would be above the hips when driving. Above him, next to the main hatch, which swung to the right when opened, he had a single dome light. In case of an emergency exit, he had a round exit hatch to his left in the hull floor.

Driver’s position in the PT-76.
Source: PT-76 manual
POV of the drivers seat in the PT-76. Note the three batteries on the right side.

Commander/Gunner

Besides his gun sight, the commander had three periscopes in a cupola capable of rotating 360°. However, there was nothing to grab the cupola with directly, resulting in the commander having to grab onto the periscopes, which were not especially ergonomic, if he wanted to rotate the cupola. If he wanted clearer external vision (as many tank commanders prefered), he could open the hatch in which the cupola was incorporated. Despite having just 6 mm (0.2 inches) of armor, the hatch was rather large, making it very obvious to enemy snipers when the hatch was open and the commander may be looking out. This hatch was built within another, much larger hatch, running across the entire turret. The reasoning behind this was to make it easier for the crew to bail out in case of emergency. The weight of the hatch made it rather cumbersome and difficult to open, especially if a crewman was injured. In the same manner as the smaller hatch, it opened forwards to provide some kind of protection while exiting.

The already overworked commander also operated the radio, a 10RT-26E, standard to Soviet vehicles of the period. It was mounted to his left, to give him the maximum amount of space. The obnoxious overworking of the commander is rather reminiscent of commanders in French tanks in the Second World War. While the PT-76 has nothing in common with them, the situation the Soviet Union found itself after WW2 is akin to that of France in the 30s. Both nations had just fought a bloody war, bringing their population numbers low. Having fewer crewmen per tank would mean, in the greater picture, a significant saving in resources and manpower necessary for operating the tanks.

View of the turret and crew positions with the breech of the gun in the center.
Source: PT-76 Manual
Main hatch in the turret. The commander’s hatch was built inside the main hatch. Exiting and entering the tank for the two crew members in the turret was done by opening the main hatch.
Source: thesovietarmourblog.blogspot.com
Inside view of the main hatch. The three periscopes from the commander’s smaller hatch can be seen.
Source: thesovietarmourblog.blogspot.com
The field of vision for the periscopes in the PT-76 1952 alteration.
Source: thesovietarmourblog.blogspot.com

Loader

The loader sat on the right side of the turret, to the right of the main gun, meaning he had to load the gun with his left arm, a common feature of Soviet tanks of the time. He had three main duties, loading the 76 mm gun, loading the coaxial machine gun and, when not loading, he was responsible for assisting the commander in surveilling the surroundings with his single rotating MK-4S periscope. Due to the design and placement of the periscope, the loader has vision forwards and slightly to his right. To extend his vision, he has to swap and reverse the periscope, allowing him to look to his rear. This was rather inefficient, making it hard for the loader to aid the commander in spotting targets and with overall vision.

The only periscope for the loader. With a bit of imagination, it can be imagined how the loader cannot look behind him, the turret wall is in the way. This requires for the periscope to be reversed.
Source: thesovietarmourblog.blogspot.com

The loader had plenty of space to operate. He had a folding seat mounted to the turret ring, meaning that he could work standing or seated. His comfort did not stop there, he had a dome light and a backrest, conveniently tilted so that it faced the gun. There was so much room in the turret that, after folding the recoil guard to 90°, there was a large gap between the two crew positions, through which the crewmembers were able to pass.

Polish PT-76 loader.
Source: 7ldd.ocalicodzapomnienia.eu

Thanks to the large amount of real estate in the turret and the relatively small size of the 76 mm shells, the loader’s job was not that complicated. This allowed for quite a short reload time in between shots, with a theoretical 15 rounds per minute (4 second reload). However, actual firing speed, taking aiming into consideration, would be below seven rounds a minute.

Overview of the loader’s station. His rounded foldable seat is facing the gun. Meanwhile, the machine gun is very close and easy to access. Note the empty ammunition ready rack in the bottom corner.
Source: thesovietarmourblog.blogspot.com

The ammunition was stored in a ready-rack, in two stacks of seven (14 rounds), to the loader’s left, inside the turret bustle. On top of this ready rack, on the turret wall, were an additional two rounds. On the other side of the turret bustle, underneath the gun, there was the storage ammunition rack, with an additional 24 rounds, bringing the total ammunition to 40. This is rather low for a tank its size, but it was a considerable improvement over the R-39 prototype, which had just 30. Extracting ammunition and loading the gun directly from the storage rack was rather cumbersome. Ideally, the rounds had to be taken out and put inside the ready rack when not in immediate combat.

Ammunition storage in the tank. Worthy of note are the positions of the ready rack and large storage ammunition box.
Source: thesovietarmourblog.blogspot.com

Armament

The PT-76 used a 76 mm D-56T gun. Developed by Factory No. 9 in 1949 based on the F-32 and ZiS-3 guns, it in fact had identical ballistical capabilities and fired the same ammunition. Both the F-32 and ZiS-3 were deemed obsolete by the end of WWII, and rightfully so. Their replacement with 85 mm and larger guns could be seen with the T-34-85. In 1947, an 85 mm gun was wanted, but due to the weight reduction to only 15 tonnes, a 76 mm gun had to be used. It is noteworthy to mention that the doctrine of the PT-76 meant that this otherwise obsolete tank gun was enough. The purposes of the PT-76 were to support troops during amphibious landing by neutralizing machine gun nests and recoilless rifles and other soft targets. The gun could depress -3.5° (-4 according to other sources) and elevate +31°. Executing a complete rotation of the turret took around 21 seconds with manual hand crank. The gun was also capable of indirect fire with an azimuth sight. It was capable of firing 15 rounds per minute, but most loaders managed 6 – 8 rounds a minute.

The D-56T inside a cutout PT-76 turret. Note the long, TsAKB muzzle brake. This version of the gun would be replaced in 1957 with a D-56TM, when the PT-76 would be revised and called PT-76B.

The D-56T on early PT-76 tanks used the TsAKB style muzzle brake, with many vertical slots, pushing the blast backward, greatly decreasing the recoil. Another innovative feature of this gun was that the recoil buffer was mounted underneath the breach, to the right, and the recuperator to the left. Usually, in guns of the time, especially in Soviet tank guns, these components were mounted on top and or in front of the breech. This new placement allowed for less space needed over the gun, increasing gun depression or allowing to decrease the height of the turret.

The recoil buffer (right) and recuperator (left).
Source: thesovietarmourblog.blogspot.com

Another unusual feature of the D-56T was the vertical sliding breech lock. On most Soviet tanks of the time, the breech lock was horizontal, and on the right side. There were two reasons. Primarily, Soviet doctrine stated that if the axis of the gun breech is lower than 950 mm to 1000 mm from the floor, a vertical breech lock should be used. Anything higher than that should use a horizontal breech. This rule was set as vertical breeches are easier to load when lower down, however, much harder to load when higher up. The exact measurements are made in proportion to the elbow and shoulder of the average Soviet tanker, at 1.70 m (5’ 6” feet). Lastly, as it was a small field gun, the ZiS-3 already had a vertical breech lock.

Later, in 1957, this gun would be changed to the D-56TM gun, with a German-style muzzle brake and more. Furthermore, in 1961, a second gun upgrade was made, with the D-56TS. It now received a two-plane stabilization device.

Ammunition

The ammunition used by the D-56T in the PT-76 is identical to that on the ZiS-3. They used 76.2 x 385 mm rimmed munitions. Since the two guns shared ammunition, there was a large variety of munitions readily available. A battle-ready PT-76 would have the following ammunition loadout:

24 High Explosive (HE) rounds
4 Armor-Piercing High Explosive (APHE)
4 Armor-Piercing Composite Rigid (APCR)
8 High Explosive Anti-Tank (HEAT)

This loadout changed in the 1970s. It now had 20 HE shells and 12 HEAT shells instead.

It is worth mentioning that, despite the age of the rounds used and the gun itself, the PT-76 was capable of, theoretically, countering western counterparts, such as the M41 Walker Bulldog or AMX-13, and even lightly armored MBTs, such as the AMX-30 or Leopard 1. However, towards the end of the 50s, it was clear that the gun and ammunition were not capable of dealing with modern medium and main battle tanks.

Secondary armament

The secondary armament on the PT-76 was, as standard on Soviet tanks of the time, a coaxially mounted 7.62 mm SGMT machine gun. Four magazines were carried in the tank, each of 250 rounds, making a total of 1,000 rounds. This is very little considering that the PT-76 was the only tank used by Soviet naval infantry. To put this into perspective, a T-55 carried 3,500 rounds. The crewmen had AK-47s as their personal defence weapons.

SGMT machine gun for mounting on tanks.
Source: Arundel Militaria

Engine

As mentioned earlier, the PT-76 mobility and top speed are not as impressive as many other light tanks of the era, focusing more on its amphibious aspect. The main engine was a V-6, 6-cylinder in-line, 4-stroke, water-cooled diesel, capable of delivering 240 hp (179 kW) at 1,800 rpm. This engine was a simplified version (literally cut in half) of the well-known V-2 engine, used on the T-34, KV, and IS tanks. Originally, a T-34 transmission was proposed, but a more complex one was needed to power the waterjets, thus a new transmission was created, specifically for the PT-76. Nonetheless, it was similar to that on the T-34, a manual shaft transmission, with four gears forwards and one in reverse. It also used a simple clutch braking steering system.

This engine gave the 14.6 tonne (16 US tons) vehicle a power to weight ratio of 16.4 hp/ton, a top speed of 44 km/h (27.3 mph) and a range of up to 400 km (249 miles). Initially, it had a 250 liter fuel tank on the rear right side of the hull. Additional fuel tanks of either cylindrical drum or flat rectangular types could be stowed on the engine deck for additional autonomy. They were not connected to the fuel system. On the PT-76B, fuel consumption was 4.5 liters a minute.

V-6 in-line engine, very similar to the famous V-2.
Source: thesovietarmorblog.blogspot.com

Suspension

Like the majority of vehicles of the era, the PT-76 used torsion bar suspension. On the first and last torsion arm, hydraulic shock absorbers and a volute spring were mounted to improve the ride quality when crossing over larger obstacles. Having a 670 mm diameter (26.4 inches), the road wheels were of completely new design, and are now one of the most recognizable aspects of Cold War Soviet armor, as the PT-76 served as a basis for a multitude of vehicles.

Originally, the wheels were made out of smooth surfaced stamped steel, but slowly got replaced by wheels with stamped reinforcement ‘ribs’. These wheels were hollow on the inside, helping the buoyancy of the PT-76. The indentations in the wheel improved traction in snowy or muddy environments.

The tracks were of cast manganese steel, connected with steel pins with between 96 and 108 links per side. Additional spare track links (typically 3) were stowed on the rear of the turret.

View of the sprocket and wheel of the PT-76. The tracks had a single pin, was 360 mm (14.2 inches) wide and 96 links were used per side, with no return rollers. Note the distinctive stamped hollow wheels.
Source: Brittmodeller.com

Water propulsion

The most important feature on the PT-76 was its ability to swim. A lot was sacrificed on the tank to allow this, like the smaller gun and little armor, combined with a longer and wider hull. As mentioned previously, there were many proposals on what the water propulsion system should be. Among these were propellers in water tunnels, conventionally mounted propellers on hinges, water-jets, and lastly, tracked propulsion. Eventually, water-jets were chosen. These worked by using two main jets with openings in the floor of the tank. Water would be pumped up and propelled out the back of the vehicle through two holes, creating thrust. To steer, either one of the holes was shut. For example, to turn to the right, the right hole was closed while the left was still running causing the vehicle to slew to the right. Closing the ports to the jets forced the water to exit under pressure through the ports on the side, forcing the water forwards. When reversing, both rear jet holes were shut, redirecting the water to the two smaller ports on the side of the vehicle. This system was designed by Nikolai Konowalow.

Diagram showing steering of PT-76 in water.
Source: m.blog.naver

The PT-76 is famous for its outstanding amphibious capabilities, being the primary reason for its prolonged service life. The top speed when swimming of 10.2 km/h (6.3 mph) or 11 km/h, depending on source, is more than adequate.

PT-76 Model 1957 (or later) during a massed amphibious assault practice.
Source: thesovietarmourblog.blogspot.com

Armor

With amphibious assaults and reconnaissance in mind, the PT-76’s armor protection was comparable to other amphibious armored vehicles of the time. This was considered enough to protect from small arms fire or fragmentation, though the overall level of protection was still relatively poor compared to other light tanks of the time.

The turret is conical in shape, angled at 35°, improving its armor effectiveness. At the front, it is 15 mm (0.6 inches) and narrows down to 10 mm (0.4 inch) at the rear.

Armor profile of the initial PT-76 light tank. The armor profile changed in 1962 and in 1967.
Source: thesovietarmourblog.blogspot.com

The hull was equally lightly armored. The front upper plate was 10 mm angled at 80°. This greatly improved the chance of ricochets from small arms. The lower plate, being tall and only angled at 45° was thicker, at 13 mm. The flat side armor was 13 mm on the top half, and 10 mm on the lower. The rear and roof plates are 6 mm (0.23 inch) thick. The bottom was only 5 mm (0.19 inch). Theoretically, this made the PT-76 vulnerable to heavy machine gun fire from the side and rear, yet this was very unlikely in battlefield conditions. The light tank was vulnerable to the Soviet 14.7 mm KPVT heavy machine gun, but the western countries did not have such large machine guns in service.

Service Upgrades

Like many Soviet vehicles of the time, many changes were made throughout its lengthy service life, as the potential battlefield changed, and different obstacles appeared. These were named with “Обр” (obrazets) essentially meaning year model.

PT-76 Mod. 1951

This was the very first production model, essentially the Object 740.

PT-76 model 1951 at Kubinka
Source: m.blog.naver

PT-76 Mod. 1952

The splash guard was made thicker (from 10 mm to 20 mm) and a second water pump was added. The most noticeable change is the introduction of the rib model stamped wheels.

The new, stamped model wheels provide better traction. Note that they are hollow, for better buoyancy.
Source: M.Blog.Naver

PT-76 Mod. 1953

Armor was increased slightly and a MK-4 observation device port was added. Furthermore, various structural designs were improved.

PT-76 Mod. 1954

Driver’s hatch opening and closing was changed to that of the T-54 mechanism, improving driving in bad conditions. Oil filters, antifreeze filters, and other such equipment was changed and added.

PT-76 Mod. 1955

Track center guide width was increased from 4 mm to 6 mm. Clutch and brake pedals received springs for easier and more comfortable usage by the driver. Improved fuel absorption pump for starting in low temperatures.

PT-76 Mod. 1956

UBR-354M HEAT ammunition was added. Ventilators for the rear cover and special lids were added to prevent water leakage.

PT-76 Mod. 1957 (PT-76B)

By far the most important and extensive change made to the PT-76 durings its service life was the PT-76 Mod. 1957, also known as the PT-76B. Developed at STZ with chief designer S. A. Fedorov, this new upgrade received the name Object 740B.

The primary upgrade was to the gun, changing from the D-56T to the D-56TM. A new ‘German-style’ muzzle-brake was given. The previous slotted muzzle brake blew the gases towards the rear at very high pressures, potentially harming infantry riding on the tank. As Soviet doctrine implied the PT-76 was to carry 20 infantrymen over bodies of water and still be able to engage targets afloat, the last thing it needed was to have the infantry fall off or be injured because of the muzzle blast. Additionally, a hydraulic piston was added for elevation and depression of the gun. The ‘German-style’ muzzle brake was much shorter as well, minimising the risk of damaging the barrel or dirt clogging the barrel in amphibious operations. The hull was heightened to 2,255 mm.

The different types of muzzle brakes and the direction through which they push the gases. Type A was used on the D-56TM.
Source: thesovietarmourblog.blogspot.com

The vehicle also received designated CBRN protection, which included a gamma radiation meter.

PT-76 Model 1957 during an amphibious assault. Note the new D-56TM gun and longer TNP-370 periscope.
Source: m.blog.naver

PT-76 Mod. 1958

The hull was heightened by 60 mm (2.36 inch), reinforcement plates were added to prevent warpage in the structure from the waterjets, auxiliary fuel tanks (not connected to the engine) were added. Likewise, a gyro-compass was given to the driver and an additional external tow hook was mounted on the frontal side of the hull.

PT-76 Mod. 1959

New, more durable FG-10 and FG-26 headlights replaced the old ones and the hull was strengthened with plywood, to keep the weight down.

PT-76 model 1959. Note the new headlamps on the tank.
Source: m.blog.naver

PT-76B Mod.1961

Around the 1960s, many older Soviet AFVs underwent major changes, the ISU-152 and T-54 being good examples. The PT-76 was no exception and throughout the 1960s, significant changes were made.

PT-76B Mod. 1961 swimming. Note the external fuel tanks.
Source: m.blog.naver

The main improvement was the upgrade to the D-56TS gun. This new gun had a two-plane stabilizer named STP-2P ‘Zarya’, allowing the gun to stay locked on a horizontal and vertical level but also on one chosen by the gunner. It had two main modes, automatic and semi-automatic. The automatic mode was used in combat, with the entire system running. Semi-automatic was used during stabilization failure and was considerably slower.

After firing, the stabilization mechanism would hydraulically lock the gun in place. This prevented the gun from rising due to recoil, allowing the gunner to view the target and observe the shot. The gun remained locked until the loader pressed the safety button after he had loaded the gun. This restabilized the gun. Unlike other stabilizing equipment found on MBTs, the gun did not rise upwards (breech downwards) to ease the loading process. One such system was the STP-2 on the T-55. However, this feature was not deemed necessary, as the 76 mm shells used by the D-56TS are a lot lighter than the 100 mm ones on the T-55 or other MBTs with even larger guns.

The D-56TS also featured a recoil guard mounted to prevent the casing from hitting the crewmen. A hydraulic elevation piston was also added, as previously, the elevation mechanism of the gun was mechanical. The turret was heightened by 25 mm (0.98 inches), mainly because the turret rotation mechanism was changed. Waterproofing integrity of the turret was also improved.

Additionally, air filters and fuel tanks were reworked once again. New instrument panels were given to the driver and for the turret junction box. A TPU R-120 communication device was installed, and an R-113 Granat radio replaced the old 10RT-26E radio. The difference in frequencies was large; 3.75 to 6 MHz from the old one to 20 to 22.375 MHz. A smokescreen generator was also added, creating smoke that could last from two to 10 minutes (depending on the wind) over a distance of 300 to 400 meters (984 to 1,312 feet). The driver was given two situational periscopes. A TNP-370 elevated periscope was added, which allowed the driver to see better while the tank was swimming, since it was elevated by 370 mm (14.6 inches). Secondly, a TVN-2B night vision device was given to the driver, extending his vision up to 60 meters (197 feet) in the darkness.

All these new electric elements greatly increased the usage of electricity in the tank, so a G-74 generator was installed, alongside a PPT-31M relay controller.

Crew comfort was also improved, the commander received an adjustable backrest and footrests on the turret floor.

To the left is the driver’s control panel or dashboard pre-1961 and to the right is the new version.
Source: m.blog.naver

PT-76B Mod.1962

In January of 1962, a VTI-10 two-stage air filter was equipped, also giving a dust remover for the exhaust of pistons 3 and 4. Additionally, fuel capacity is increased to 390 liters (103 gallons). At the request of the Soviet Navy, a new air intake pipe was mounted in the turret, to improve landing conditions.

The hull was made 70 mm taller (2.75 inch) and the lower front hull was angled inwards at 55°, as opposed to 45°. Armor thickness changes were made as well.

The new armor layout for PT-76B Model 1962. The upper plate was thinner, while the lower plate was made thicker and more angled.
Source: m.blog.naver
PT-76B Mod.1962. The sharper nose, thanks to the 55° lower plate can be seen.
Source: m.blog.naver
PT-76 (left) and PT-76B Mod.1962 to the right. The differences in hull height can be seen.
Source: m.blog.naver

PT-76B Mod.1963

In May 1963, the torsion bars for each side were made interchangeable, improving repair and logistics. To prevent hazards when transporting, the engine deck was also fitted with a travel lock for the gun.

PT-76B Mod.1964

A more efficient engine heater was added, decreasing the time necessary to heat up the engine in low temperatures. Additionally, the driver’s gyrocompass was upgraded to a GPK-59 and the periscopes got thicker armor. The engine was replaced with a V-6B engine.

PT-76B Mod.1965 and PT-76 Mod.1966

Small technical improvements were made to the engine heater, oil filter, driver’s station light, etc. In May 1966, an armored cover was mounted over the TShK-66 sight to prevent debris and spalling from entering the turret.

PT-76B Mod.1967

The last year in which the PT-76 was produced. The track model was redesigned and the thickness of the steel they were made of was increased to 2 mm (from 1 mm). The radio and antenna were upgraded to the R-123 and TPU-R-124 models. More importantly, the co-axial machine gun was changed from an SGMT to a PKT. The armor profile was changed again, this time increasing the lower rear armor plate to 8 mm (0.31 inches).

The armor profile remained largely the same, however, the rear plate was thicker.
Source: m.blog.naver

Problems

Throughout its service life, the PT-76 suffered from a handful of fundamental issues that could not be solved through minor upgrades. Firstly, the main 76 mm gun was not seen as powerful enough and was ineffective against the more modern Western tanks, like the Patton and Centurion. Secondly, the very thin armor combined with a large hull made it a very vulnerable vehicle, regardless of its use on the battlefield. Lastly, it had poor scouting abilities, being very loud, tall, and without proper scouting equipment.

The PT-76 was excellent at what it was designed for – ‘swimming’. However, this came at the price of sacrificing essentially all other combat capabilities. As the only light tank in the Soviet arsenal, it could not perform deep penetration within enemy lines or take on other medium tanks or MBTs while it waited for the heavier tanks to arrive. The 76 mm gun was, at best, satisfactory at the time of development, but it was clear that it would be obsolete quickly.

Unfortunately for the light tank, it never got to be used at what it was designed for – eastern and central European fields and swamps, but rather in a variety of other wars and low-intensity conflicts in other parts of the world, from Vietnam to South Africa. Given the specific niche it was designed for, it is perhaps inevitable that these non-Soviet users ended up using it incorrectly. These deficiencies in its use were highlighted when it was pitted against other tanks and, especially, handheld anti-tank weapons. Alternatively, its bad reputation was mostly caused by bad doctrine and poor usage rather than a bad design, but this is a debatable point.

Although, when employed correctly, as the Indian army did in 1971, the PT-76 could surprise its attackers and cross terrain that no other tank could. Unfortunately, PT-76s were quite often operated as a medium or MBT, and lacked support from heavier tanks, like originally intended.

It is also valid that the tank was doomed from the start in terms of armament. It is possible that Soviet designers underestimated the evolution of medium and light tanks in the West, claiming that the gun was very adequate for WW2 era medium tanks like the Pz.Kpfw. IV, but did not foresee the heavy armor on tanks like the M48 Patton.

Even against contemporary light tanks, like the AMX-13 and M41 Walker Bulldog, the PT-76 was inferior in general combat terms, lacking in firepower, speed, and armor. The PT-76 did excel over its rivals in mobility in rough environments, like swaps, deep muds and snow, and, of course, water bodies.

Further prototypes

The obsolescence of the PT-76 was becoming more and more apparent at the end of the 1950s, with new, and better armored Western tanks appearing. Soviet designers got working on several solutions, fixing fundamental issues in different ways, either armament or size. However, their complexity, price, and the development of the BMP-1 canceled them all.

PT-76M (Object 907)

In 1959, an attempt was made to improve the survivability and mobility of the PT-76 by the designers at STZ. A new welded hull was made with up to 80 mm of armor. It was reshaped, closer to the shape of a boat. The weight increased to 14.87 tonnes, so a new V-6M engine delivering 280 hp was added. Additional fuel tanks were added for an increased range of 400 km. Speed on land remained at 45 km/h and on water at 11.2 km/h. This vehicle was the PT-76M / Object 907 (not to be confused with the medium tank with the same index).

In August of 1959, the one and only prototype was built, but after testing, the new hull actually impaired the floating capabilities. All in all, there were no significant improvements over the standard vehicle and it was canceled.

The PT-76M modernization. Note the angling in the front of the hull and towards the sides. Turret and armament remained identical.
Source: Reco Monkey

PT-85 (Object 906)

Also at STZ in 1960, a project was started with the aim of improving the firepower of the PT-76B. Capital changes were made to the tank. Firstly, and most importantly, was the installation of the 85 mm D-58 rifled gun, fitted with an autoloading system and a highly effective two-plane stabilization system. In addition, an 8D-BM 300 hp diesel engine replaced the previous 240 hp, which allowed for top speeds of 75 km/h on land and 10 km/h on water, despite the 15-tonne weight. Six prototypes were built by 1963 at the now renamed Volgograd Tractor Plant. The military was not particularly interested in the project, as it was expensive and complex, despite the rather obvious advantages over the PT-76B. There was also an Object 906B, which was a low-profile light tank design, meant for scouting and other purposes.

PT-85 or Object 906. Note the completely redesigned turret, with the more powerful 85 mm gun.
Source: Reco Monkey
Object 906B light tank. It never left the drawing board.
Source: Solyankin A.G., Pavlov M.V., Pavlov I.V., Zheltov

Object 8M-904

This peculiar and fascinating vehicle was a 13.5-tonne testbed based on the PT-76 of an armored hovercraft. The turret was removed and, instead, an aircraft engine was installed, delivering 200 hp. Testing proved satisfactory and it proved the viability, or at least, the worthiness of experimenting with armored hovercrafts, or more literally, floating tanks.

Object 8M-904 testbed. Note the additional changes made to the hull, like the heightening the running gear to allow space for the air skirt underneath the hull.
Source: Domestic Armored vehicles 1946-1965

PT-76B with 9M14 Malyutka

In late 1964, tests were carried out for equipping existing Soviet armor with 9M14 Malyutka wire-guided anti-tank missiles. One of these was a PT-76B, which got equipped with a special launcher for said missile. After trials were undertaken at the NIIBIT proving grounds, the PT-76B system was dropped due to its unreliability. It is sometimes referred to as PT-71, however, there is no proof of it being called this officially and is plausibly a confusion.

A PT-76B with the 9M14 Malyutka ATGM.
Source: WT Forums

Object 170

As ATGMs became more prolific and popular in the 1950s, Soviet engineers tried a large variety of self-propelled ATGM vehicles. One of the lesser-known attempts was the Object 170, which used a PT-76 chassis. Its turret was removed, and instead, a turret with two drum missile launchers, equipped with 5 x 100 mm NURS missiles each. In between them, was the mounting for a 140 mm missile. The project was canceled in 1959 due to the complexity of developing a functional missile fire control system.

The Object 170 used a PT-76 hull but moved the entire crew inside the hull.
Source: Source: Domestic Armored vehicles 1946-1965

Object 280

Developed in 1956 to provide support for troops, this variant used two launchers, each with 16 x BM-14 artillery rockets. Getting it ready to fire took 1 to 2 minutes and so did the reload. Allegedly, one prototype was built and passed factory tests, but state trials were unsatisfactory and the project canceled.

PT-57/PT-76E

A more recent attempt to upgrade the PT-76 in Russia was the PT-57, sometimes called PT-76E. Based on the PT-76B, it used a new 57 mm AU-220 autocannon, an improvement of the S-60 AA autocannon, featuring an automatic loading system. It also received a new 300 hp engine, giving the vehicle a top speed of 60 km/h. Allegedly, Russian Marines placed an order of 50 to 60 units in 2006, but it never materialized, likely due to the obsolescence of the chassis, budget cuts, and other, more promising programs.

PT-57 or PT-76E during trials.
Source: Topwar

Muromteplovoz PT-76B Modernization

Another smaller-caliber plan to keep the PT-76B relevant was the modernization made by Muromteplovoz JSC. The updated version replaced the original engine with a 300 hp YaMZ-7601 engine, propelling the vehicle to up to 60 km/h on road and 10.2 km/h in water. General reliability and repairability were also improved, including increasing parts commonality with the MT-LB. The driver controls are smoother, leading to decreased crew fatigue. The most visible change was to the armament, swapping the original turret with an MB2-03 turret (also manufactured by Muromteplovoz) which featured a 30 mm 2A42 automatic cannon, a 7.62 mm PKTM machine gun, and a 30 mm AG-17 automatic grenade launcher. The weapons system was primarily used against soft targets and low-flying aircraft and utilized a two-plane stabilizer and TKN-4GA day-night sight. Elevation angles were between -5 and +70 degrees. All ammunition was stored in the hull of the vehicle. Similar modernizations are also available for vehicles such as the MT-LB, BMP-1, various BTRs, and other vehicles.

The promotional image from Muromteplovoz for their PT-76B modernization.
Source: muromteplovoz.ru

Variants

As the PT-76 offered a light and versatile chassis, specially designed to be easily redesigned for other uses, it branched off into other variants. The main one was the BTR-50, co-designed with the PT-76 from the very start. Later in the ‘50s and ‘60s, as the effectiveness, popularity, and threat of missiles became larger and larger, various close to long-range missiles systems were made based on the PT-76 chassis, like the ballistic missile launchers 2K1 Mars and 2K6 Luna, but also defensive surface-to-air missile systems like the 2K12 Kub. Various conventional systems were also designed, like the short-air defense ZSU-23-4 Shilka, airborne assault gun ASU-85, or GSP mobile ferry.

BTR-50

One cannot mention the PT-76 without raising the BTR-50. Developed alongside the light tank, it became the first Soviet tracked armored personnel carrier. Having the same hull as the PT-76, the fighting compartment was raised, allowing for the transport of troops. Initial variants were open-topped, but later received a roof and were renamed BTR-50PK, among other changes. Well over 6,000 units were built, but was, just like the PT-76, replaced by the BMP-1.

BTR-50PK during a parade. Note the open roof hatches and InfraRed (IR) light. Source: Pinterest

2K1 Mars

As conventional artillery cannons grew heavier and larger in the 1950s, ballistic missiles were developed onto vehicles to make them mobile. The 2K1 Mars was one of the first such systems to enter service within the Soviet military. Based on the chassis of the PT-76, the turret was removed, with the missile launcher placed across the length of the hull, thus creating the SPU 2P2 hull. The launcher could pivot on the spot where the previous turret was. The range of the missile was quite short, between 7 and 18 km. Several problems, like damage to the chassis from the rocket launch were noted. Production started in the mid-1950s, albeit after just 25 units delivered, focus shifted on the more performant 2K6 Luna missile system. It had a loading vehicle also based on the PT-76 called the 2P3.

Despite the limitations of the 2K1, it offered a basis for future Soviet ballistic missile systems.
Source: Militaryrussia.ru

2K6 Luna

The 2K6 Luna was a further development of the 2K1, with more advanced 3R9 (HE) and 3R10 (nuclear) missiles, capable of reaching a distance of 45 km. The launcher itself was the 2P16 chassis, with the index Object 160. The loading vehicle was the 2P17. Production started in late 1959 and the first units were received in 1960 and would remain in service until 1982. It was also exported to Second and Third world nations.

2K6 Luna ballistic missile system, mounted on the 2P16 carrier chassis, in itself based upon the PT-76.
Source: Weaponsystems.net

GSP tracked self-propelled ferry (Izdeliye 55)

The GSP (Rus: Gusenitschnyi Samochdnyi Parom; Eng: Tracked self-propelled ferry) was intended to shorten and simplify the movement of medium and heavier tanks and other equipment over bodies of water. When two units were placed side by side, they would drop a pontoon on either side, thus creating a moving pontoon or ferry. Also based on the PT-76, but its engine was replaced with a much smaller 135 hp YaZ-M204V 2-stroke engine, limiting its top speed to 36 km/h on land and 8 km/h on water.

A single GSP ferry. It would drop the pontoon on one side (in the case of the vehicle in the image above, left) to transport equipment across riverbanks.
Source: Obordow.ru

ASU-85 (Object 573)

The ASU-85 was an airborne assault gun developed in the late 1950s to replace the obsolete ASU-57 for the Soviet Airborne troops. It mounted an 85 mm D-70 2A15 gun in a conventional armored casemate. It was also based on the hull of the PT-76, but it was no longer amphibious and the engine was changed to a YaMZ-206V engine with 210 horsepower, allowing it to reach 45 km/h. However, it quickly became clear that AFVs with hull-mounted armaments were no longer necessary, and it was replaced in the 70s by the much more nimble and amphibious BMD-1 IFV.

Paratrooper’s ASU-85 on parade at the Red Square.
Source: Pinterest

ZSU-23-4 Shilka

One of the most capable SPAAGs of the Cold War, the ZSU-23-4 Shilka was developed after 1957, but only entered service only in 1965. Featuring 4 x ZU-23 23 mm autocannons and equipped with a radar, the weapon system could fire 4,000 rounds per minute. Consequently, the Shilka was an extremely dangerous threat for low flying aircraft, like helicopters. Its chassis was based on the PT-76, named the GM-575, although the upper hull was radically changed. The front lower plate, normally very large on the PT-76, was lowered down, making space for a large superstructure. Another 6,500 systems were produced and exported across the world.

ZSU-23-4 Shilka SPAAG. Note the redesign of the upper hull, for instance, the driver’s hatch. Source: Net-Maquettes

2K12 Kub

Whereas the Shilka excelled at close-range anti-air support, the 2K12 surface-to-air missile system offered protection over a greater area. Equipped with large 3M9 frag-HE missiles, which could reach an altitude of 14,000 m and a range of 24 km, the system was deemed satisfactory for serial production only by 1967, almost 10 years after development started. The 2P25 TEL (Transporter Erector Launcher) was based on the GM-578 while the 1S91 SURN radar vehicle was based on the GM-568, both of which were similar to the chassis for the Shilka, barring smaller details, like hatches. Naturally, other vehicles completed a battery, like a missile transporter. These systems saw widespread use throughout communist states and affiliated, and are still widely in service today.

The 1S91 SURN radar (left) and 2P25 TEL (right), part of the 2K12 Kub air-defense missile system. Source: SimHQ

Shmel class gunboats (Project 1204)

One of the more curious uses of the PT-76, or more precisely, its turret, was on the Shmel-class gunboats. In the 1960s, the Soviet military began the development of a new gunboat that was capable of sailing through narrow and shallow rivers, but also getting closer to the shore for the support of ground troops. Naturally, this meant it was rather small, being only 27.70 meters long, 4.3 meters at beam, having a remarkably shallow draft of 0.8 meters, and a total displacement of about 70 tonnes. Powered by two 1200 hp M-50F-5 diesel engines, it could make up to 26.2 knots (48.5 km/h). However, the main forte of these gunboats was the number of onboard armaments. At the bow, the turret of a PT-76B, including its 76 mm gun and coaxial 7.62 mm machine gun, was mounted, offering both direct and indirect firepower against enemy forces and positions at closer ranges. On later models, a 140 mm BM-14-17 MLRS was mounted near the center of the ship for longer-range barrages. At the stern, either a 2M-6T turret with twin 14.5 mm machine guns or a 2M-3M turret with twin 25 mm autocannons could be fitted, being found on early- and late-production vessels, respectively. Additionally, four 30 mm AGS-17M automatic grenade launchers, all contained within an armored cabin, could be found directly aft of the bridge on later vessels. To top things off, it featured a minelayer with a complement of 10 mines. It entered service in 1967.

Shmel class gunboat, firing its 76 mm D-56TS gun.
Source: Anton Blinov

BMP-1 Development and other light tanks

The PT-76 was undoubtedly the starting point of many light tanks and IFV projects in the 1960s, like the Object 911, 911B, 914, and 914B, just to name a few. The 911 and 914 were APC prototypes, in the competition for a new IFV, the BMP-1. The Object 911 had hydraulic suspension and retractable running gear, similar to a wheel-cum-track system. This allowed it to achieve high speeds both on roads, with the help of tires, but also a good off-road performance from the tracks. In contrast, Object 914 was a much more conventional vehicle, very similar to the PT-76. To boost its firepower, firing ports for the infantry were placed throughout the vehicle, including two in the front, giving it a very unusual look. Both prototypes were built and tested, and now rest at Kubinka tank museum. The Object 911B was a light tank project, focused primarily on having a very low profile. This was done to decrease the probability of being hit, but also minimize the level of armor needed. A low-profile tank is also much harder to hit.

Object 911 IFV prototype. Note the rear entry passage for the infantry.
Source: Pinterest
Object 914 IFV prototype. Note how similar the hull is to that of the PT-76.
Source: Kubinka
The Object 911B had hydraulic suspension and was able to lower its hull, to touch the ground, similar to that of the E-10 German tank destroyer. Here it is in the driving position, next to a PT-76B.
Source: Domestic Armored vehicles 1946-1965

Chinese Type 63

China received a number of the Soviet PT-76 tanks in the mid-1950s and by 1958 decided to build their own light tank, taking ‘inspiration’ from the Soviet design, albeit with various changes made. The driver sat on the left side of the hull, the crew was increased to 4 and the weapon was a more capable 85 mm Type 62 rifled gun. The most remarkable difference, however, is the amphibious propulsion, as the Chinese tank is also able to use its tracks for water propulsion, not just the water jets. It entered production in 1963 and branched off into many variants and modernizations. It is still in service in the PLA and various other nations.

Chinese Type-63 amphibious light tank, heavily inspired by the PT-76, but with significant changes.
Source: Military Today

North Korean M1981

The M1981 is a North Korean light tank developed in the late 1970s; though it takes some inspiration from the Soviet tank, mechanically, it is much closer to North Korea’s own 323 armored personnel carrier. The turret shows clear inspiration from the Soviet design, with a conical shape, but retains completely different hatch designs, and mounts a more powerful 85 mm gun based on a Chinese model. That gun warranted it the nickname of ‘PT-85’, given by Western enthusiasts, which largely overestimates its links with the Soviet tank, which serves as one within several inspirations to North Korea’s vehicles.

North Korean M1981 in 2009. From afar, it looks similar to the Soviet counterpart but is in fact different in every aspect.
Source: massimotessi.altervista.org

Export

The PT-76, like most other Cold War Soviet vehicles, saw substantial export to nations across Eastern Europe, Africa, and Asia. Around 2,000 such tanks were exported by the Soviet Union, out of which 941 were PT-76B models.

Finland

Finland received 12 PT-76B export light tanks from the Soviet Union in 1964 and were used until 1994. Finland also purchased 118 BTR-50s in the same period. After the retirement of the light tanks, a few were transformed into driver training vehicles for the BTR-50s. The main difference was the removal of the main gun and mantlet. In its place, a sheet of plexiglass was bolted over the gap. These were named PT-A and were also retired in 2018, alongside all remaining BTR-50 APCs.

A PT-A driver training vehicle for BTR-50 armored personnel carriers.
Source: yhdistykset-akaa.fi

East Germany

East Germany, or DDR (Deutsches Demokratische Republik), ordered 170 units in 1956, which were delivered between 1957 and 1959. These were used in exercises across the northern coast and even exercises with the Polish army and Soviet naval forces. When East and West Germany were reunited, the light tanks were scrapped or sold off to various countries.

A unique and tragic incident happened on the 24th of August 1965, when the 1st Reconnaissance Battalion, stationed in Groß Behnitz, invited schoolchildren on an amphibious ride across the local Riewend Lake. For the ride, one PT-76 light tank was used, with 21 children and guardians, plus the driver situated in the hull. They were standing across the length of the hull, however, at one point, the children towards the back moved forwards to the bow of the tank, either to get away from the hot engine bay or to hear what the driver was saying. This brought additional weight to the front, which sunk and took water over the top, further sinking the tank. Eventually, the water reached the driver’s hatch, which was open. From there, the sinking of the tank was rapid. Everyone was able to exit, but as the sinking happened in the middle of the lake, getting to shore was hard. The driver and 14 children survived, but 7 boys drowned in the accident. A local diver found the bodies and also uncoupled the tank, entering through the turret hatch. Lastly, he connected the tank with a tow hitch through which the tank was removed and pressed back into military service.

PT-76B carrying children over the Riewend. It is unclear if this was the same time as the incident or a previous date.
Source: Maz-online.de

India

India first ordered 178 PT-76 light tanks from the Soviet Union in 1962 and received them between 1964 and 1965. They first saw combat in the Indo-Pakistani war of 1965 but cemented their success in 1971, first in the Battle of Garibpur, where Indian and Bangladeshi troops, supported by Indian PT-76 tanks, invaded the then Pakistani region of Garibpur. India would continue to fight weeks later in what had now become the 1971 Indo-Pakistani war or the Bangladesh Liberation war. One hundred of the now popular tanks would continue to serve in the Indian army until 2009 when they were finally retired. These were kept in reserve and eventually scrapped, used as targets for the Indian Air Force or in museums and memorials.

An Indian PT-76 from the Battle of Garibpur, with Indian propaganda text.
Source: seniorstoday.in

India even converted an M4 Sherman medium tank with the more potent 76 mm gun from a PT-76, mainly due to the availability and reliability of M4 Sherman components, while the original guns were clearly obsolete and possibly worn out. It is unlikely that it kept the stabilizer.

Indian Sherman with a 76 mm D-56T gun from a PT-76.
Source: FTR

Indonesia

This southeastern Asian nation first ordered PT-76 tanks in 1962 and received them by 1964, but had, at most, 170 such tanks in service. They were ordered for the Cavalry, but most served with the Indonesian marines or Marinr. These first saw combat during the Indonesian-Malaysian border war in 1965, where an Indonesian marine brigade was equipped with the brand new PT-76 tanks, but also BTR-50 APCs and BRDM-2 armored cars. Following the G30S (30th September movement) coup d’etat and political issues that followed in Indonesia, the USSR placed an export embargo on the country, terminating any export of tanks and spare parts for the Indonesian vehicles. This led to the Indonesian marines having to ‘cannibalize’ their tanks to keep them in service. The PT-76 saw further combat, primarily in the invasion of East Timor, where the tanks gave a decisive upper hand in combat against weak opposition.

In the 1990s, despite the embargo, the PT-76 still constituted a large part of the armored fighting force of the Indonesian marines. Thus, a plan to modernize the vehicles started. The main upgrades were giving the tanks a Belgian 90 mm Cockerill Mk.III and a Detroit Diesel V 92, 290 hp engine, increasing the top speed to 58 km/h. This version is sometimes called PT-76M (not to be confused with the Soviet one).

Indonesian marines upgraded PT-76. The easiest way to distinguish between the standard and the upgrade is the new, triple slotted muzzle brake.
Source: VnReview

A curious vehicle is an Indonesian PT-76 with the gun removed and a BM-14-17 MLRS mounted on top of the turret.

The Indonesian prototype with a MLRS on the turret roof.
Source: WT Forums

Poland

Poland was among the first to buy the PT-76 from the Soviets, as early as 1955, with 300 units ordered, which were delivered between 1957 and 1958. These were used both as reconnaissance tanks within tank division subunits but also coastal units, namely the 7th Lusatian Landing division. Poland did conceive its own upgrades for the PT-76. Most notable is the DhSK roof-mounted heavy machine gun, which could be operated by the loader when the hatch was open. This upgrade was not given to all tanks.

A Polish PT-76 with a DhSK roof-mounted machine gun during an exercise by the coast. Note the removed muzzle brake.
Source: Twitter

Vietnam

North Vietnam first ordered the tanks in 1964, buying a total of 500 units, which were delivered from 1965 to 1973. These were second hand and some of these tanks came as aid from the Soviet Union for their efforts against western forces during the Vietnam war. The numbers grew from a single battalion in 1965 to 3 regiments by 1971. Locally, the tanks were called ‘Xe thiết giáp’, meaning ‘Ironclad’, leading to Vietnamese tanks being called as such in western literature. While it was deadly when fighting weakly prepared Laotian troops, it struggled against American troops equipped with anti-tank weapons and heavier medium tanks. After unification in 1976, the PT-76 still remained an important part of the Vietnamese tank force, which still has around 300 in service as of 2020. Vietnam also received a large amount of Chinese Type-62 and Type-63 light tanks and are used together.

Vietnamese PT-76 tanks during crew training. Note that the tank in the foreground is the earlier model 1952 variant with the D-56T gun. All the models behind are the newer PT-76 with the D-56TM gun, suggesting that the Soviet Union shipped whatever tanks they did not have in service.
Source: Pinterest

Operators list

– Angola: 68 second-hand ordered from USSR in 1975. Likely still in service
– Albania: from Yugoslavia
– Afghanistan: 50 ordered from USSR in 1958. Some likely still in service
– Belarus: from USSR, all retired by 2000
– Benin: 20 second-hand ordered from USSR in 1980
– Bulgaria: 250 ordered in 1959. Withdrawn from service
– Cambodia: 10 second-hand ordered in 1983. Another 10 ordered in 1988
– Republic of Congo: 3 second-hand ordered in 1971
– Croatia: captured from Yugoslavia
– Cuba: 60 bought in 1970
– Czechoslovakia: Tested one unit but never placed orders.
– Egypt: 50 ordered in 1958. Additional 200 ordered in 1970
– Finland: 12 ordered in 1964, Withdrawn from service
– East Germany: 170 ordered in 1956
– Germany: Received after unification with DDR (Deutsches Demokratische Republik), scrapped and sold
– Guinea: 20 ordered in 1977, second hand
– Guinea-Bissau: 10 in service
– Hungary: 100 ordered in 1957, withdrawn from service
– India: 178 ordered in 1962, withdrawn from service in 2009.
– Indonesia: 50 ordered in 1962, with additional orders up to 170 total units. They were later upgraded with Belgian 90 mm guns – and new powerplants.
– Iraq: 45 ordered in 1967 and an additional 200 in 1983, second hand. Withdrawn from service.
– Kingdom of Laos & Laos: 45 ordered in 1961, with an additional 25 captured from the NVA. 25 are in service in Laos.
– Madagascar: 12 ordered in 1983, second hand, with subsequent orders following.
– Mozambique: 16 bought from the DDR.
– Nicaragua: 22 ordered in 1983, second hand. 10 in service
– North Korea: 100 ordered in 1965. Own indigenous design was created; M1981.
– Pakistan: 32 ordered in 1968 from Indonesia, with a number captured from India in 1965.
– Poland: 300 ordered in 1955. Withdrawn from service.
– USSR/Russia: 12,000 produced. By 1991, 1,113 were still in service, some of which went to the separating nations. All have been retired during the 2010s.
– Slovenia: 10 from Yugoslavia used in the Slovenian war of independence. Withdrawn from service.
– Syria: 80 ordered in 1971, second hand.
– Uganda: 50 ordered in 1973, second hand.
– Ukraine: 50 passed on from the USSR and were all retired by 2000.
– USA: Captured units used for training in OPFOR. These were upgraded with new engines.
– North Vietnam and Vietnam: 150 were ordered by the NVA (North Vietnamese Army) in 1964. 100 more ordered in 1971. Total received was 500, some as aid. Vietnam received a large number after unification and still has around 300 in service.
– Yugoslavia: 100 PT-76B bought in 1962.
– Zambia: 50 ordered in 1983 second hand. 30 possibly still in service.

In Combat*

As a consequence of its large export numbers, the PT-76 saw service in a number of conflicts, as early as the Hungarian uprising in 1956, Vietnam War, Laotian Civil War, both Indo-Pakistani Wars, South African Border War, Six-Day War, Invasion of Czechoslovakia, Yom Kippur War, Indonesian Invasion of East Timor, Iran-Iraq War, 1990-1991 Gulf War, Balkan wars, Ten-day War, Second Chechen War and Invasion of Iraq, to name a few. The light tank’s effectiveness has been controversial, with critiques on both sides of the spectrum. On one hand, it has been widely criticized, as it showcased poor performance in battle, as its armor was thin enough to be penetrated by a variety of weapons and its armament ineffective against main battle tanks. It is worth arguing that many such incidents were cases of using the PT-76 as a regular MBT/support tank in unfavorable locations when the tank was designed to undertake amphibious assault roles and end off potential attacks until heavier tanks arrived.

On the other hand, the PT-76 has been praised in countries like India and Indonesia, which used it for a long time after decisive victories, using the excellent amphibious capabilities and the main armament, still capable of dealing with obsolete and lightly armored targets; as often encountered in such parts of the world. The success of the tank in these situations also has to be attributed to good tactics and correct usage of the tanks.

*Note that the following battles and wars will mostly try to cover information relevant to the PT-76, while still offering important information of the action’s timeline and other facts, but are incomplete, and many details are left out.

Hungarian Uprising

In the Hungarian Revolution of 1956 against the Soviet-controlled communist government, Soviet troops stationed within Hungary entered Budapest on 4th November. Sources disagree on how many tanks and AFVs were used by the Soviets, with numbers ranging between 4,000 to as low as 1,100, with the latter being more realistic. Revolutionaries had no weapons to reliably fight off Soviet tanks, many of which were IS-3 or T-55 tanks and a few of the brand new PT-76 tanks. However, due to the narrow streets of central Budapest, Molotov cocktails were used by revolutionaries to set tanks on fire. Around 700 Soviet troops were lost.

A Soviet PT-76 tank during a temporary retreat in Budapest, on Szent István boulevard. Note that it is a 1951 year model.
Source: Fortepan.ru

Vietnam war

One of the most well-known uses of PT-76 light tanks was by the NVA (North Vietnamese Army) in Vietnam. The first use of the ‘ironclads’ (the Vietnamese name for tanks) would appear in the Tet Offensive, in 1968. However, the trial by fire of Vietnamese PT-76 tanks began on 23rd January 1968, one week prior to the mass offensive. Infantry from the 24th Regiment and a company PT-76 from the 198th Armored Battalion were sent to reinforce the 304th Division. These traveled down the famous Ho Chi Minh trail, through opposing Laotian territory.

Things did not go smoothly. The PT-76 tanks often got stuck in the harsh jungle terrain and often remained behind the infantry. To make matters worse, the NVA infantry got caught in combat with the BV-33 Elefant Battalion, consisting of 700 Laotian troops at Bane Houei Sane. It was only after the light tanks had caught up that the poorly equipped Laotian troops were quickly defeated – in only 3 hours. The retreating Laotian troops settled at Lang Vei Special Forces camp. From here, on 6th February, the 24th Regiment and 198th Armored Battalion chased down Laotian troops towards Lang Vei camp, in what would become Battle of Lang Vei. This base was a U.S. Army Special forces base, manned by a detachment of the 5th Special Forces Group.

The camp was defended by around 500 civilian militia, 350 troops from the Elephant Battalion, and 24 US Army Green Berets commanded by Captain Frank Willoughby. At 18:10 hours a combined artillery barrage, consisting of mortars and later, 152 mm howitzers, opened fire at the American, South Vietnamese, and Laotian camp, damaging certain structures. Five hours later at 23:30, a second artillery barrage commenced, this time covering the advancing PT-76 tanks and infantry regiments, alongside Lang Troai road. Willoughby had been alerted that the NVA PT-76s were attacking by Sergeant Nickolas Fragos, who was in an observation tower. At last, the shelling of the camp stopped.

Three PT-76 tanks had been knocked out by a single 106 mm recoilless rifle, manned by Sergeant First Class James W. Holt, but to no avail, as 5 other NVA light tanks crushed the barbed wire and overran the defenders. Willoughby had been continuously trying to request reinforcements, while also focusing artillery fire on the attacking forces. He later also received the support of an AC-119 gunship, which delivered continuous airstrikes over the attackers. Despite the constant bombardment, NVA troops overran the entire eastern portion of the outpost by 01:15 hours the next morning. The tanks just kept on pushing forwards into the camp, destroying bunker after bunker, with the defenders in terror, as there were no weapons to engage them with. Allegedly, the tanks also depressed their guns as low as possible (-4) and engaged infantry in trenches.

On the other side of the camp, another 3 or so PT-76 tanks approached the camp and opened fire with their main guns on the bunkers, forcing the defenders to retreat towards the center of the camp, essentially squishing together the surviving forces.

Two destroyed PT-76 tanks at Lang Vei.
Source: Alchetron

At 02:30 hours, the PT-76 tanks had entered the inner defense perimeter of the camp and infantry reached the underground bunker where Willoughby, 7 other Americans, and 29 South Vietnamese and CIDG soldiers were hiding. These would stay there until later in the day, with the Vietnamese soldiers being shot when attempting to surrender (or after surrendering, or perhaps not at all, depending on the various and conflicting sources) and the US forces escaped later, being covered by artillery and airstrikes.

The camp did have, as aforementioned, only two M40 106 mm recoilless rifles, but these were not enough to stop the attack. The US troops referred to their single-shot anti-tank M72 66 mm Light Antitank Weapon (LAW) unguided rockets, but with even worse results. They often misfired, missed, or did not set off, with one source claiming that 9 such rockets were launched (and hit) at a PT-76 without doing any damage. One of the last tanks destroyed in the battle was set on fire by a direct hit with an M72 to the engine.

The battle ended in a clear NVA victory, with failed attempts at recapturing the base, like the famous one conducted by Medal of Honor recipient Eugene Ashley Jr. who died trying to recapture Lang Vei camp. Casualties were heavy on both sides. The NVA lost a number of tanks, with estimates as low as 4 to as high as 13 (some sources even state that 13 tanks were used altogether in the assault).

The battle proved once again how a well-planned attack, using the PT-76’s good cross country capabilities to maneuver through the terrain and jungle against an enemy force lacking AT weapons, can be more than enough. It was the NVA’s first major tank usage, alluding towards a promising future. However, human casualties were high. Between 90 to 167 men killed and 220 wounded. On the opposite side, 132 – 309 South Vietnamese were killed, 64 wounded and 119 captured. Seven Americans were killed, 11 injured, and 3 captured.

In an encounter of tanks against mostly inadequately equipped infantry, it is unsurprising when the tanks win, bringing to memory the old aged saying, any tank is better than no tank. A more fair comparison is the encounters with the M48 Patton main battle tank, which outclassed the Soviet light tanks in virtually every category. Allegedly, the first encounter was a bit odd. Three months after Lang Vei, a US observation plane spotted a PT-76 being washed by its crew in the Beng Hai river. Its position was sent to the US Marine 3rd Armored Battalion. One of their M48 tanks then fired indirectly, elevating its barrel into the air. It apparently only fired three shots, with the third hitting the tank and destroying it. M48 Pattons had been used for indirect fire throughout the Vietnam war, but probably not very often against another tank, considering their small size.

One of the PT-76 destroyed at Ben Het in 1969. This is the most famous example for showcasing the PT-76’s weakness. More angles and images of the same tank are available online.
Source: Steelbeasts.com

On 3rd March in 1969, the North Vietnamese, consisting of the 66th Regiment and 202nd Armored Regiment, attacked the Ben Het special forces camp in the darkness. Three M48 Pattons from the 69th Armored Regiment, alongside two M42 Duster SPAAG vehicles, were entrenched and protected with sandbags. As the PT-76 tanks attacked, leading the charge of the infantry, one struck a landmine, alerting the defenders to their exact position and illuminating the other tanks. With the help of their xenon searchlights, the M48s blinded their opponents. A ferocious exchange of fire started, with a PT-76, using the muzzle flash of an M48 as a target, hit its turret, killing two and injuring another two of the crew, although it was allegedly replaced with a new crew, and the tank put back into action. An M48 used the same tactic, knocking out a PT-76, on just its second shot, meanwhile, another M48 ran out of AP ammunition, having to switch to HE.

Second PT-76 (or BTR-50PK) destroyed at Ben Het.
Source: Steelbeasts.com

Eventually, a platoon of 3 more M48s came to help the US forces, dissipating the attackers. The following morning, US troops counted two destroyed PT-76 and one BTR-50PK.

On 9th May 1972, the North Vietnamese launched another attack on Ben Het. This time, however, South Vietnamese Rangers, equipped with UH-1B Huey helicopters mounting advanced BGM-71 TOW guided missile launchers, were on station. These could far better exploit the air superiority that US and ARVN (Army of the Republic of Vietnam) forces enjoyed, as these direct missiles did not pose a threat of harming friendly troops, like conventional airstrikes and artillery fire did. The NVA often came close to enemy positions with their tanks in order to stop them from using artillery. Nonetheless, the new system proved devastating for those on the receiving end. The helicopters destroyed 3 PT-76 tanks, forcing the remaining NVA forces to retreat, and allegedly destroying another 11 or so tanks after the initial attack. The Hueys would go on and destroy 5 more PT-76 tanks, in the same manner, a handful of days later.

The PT-76 would be used again in battles of Lac Ninh and An Loc and final campaigns leading up to the fall of Saigon.

The PT-76 was also used in the Laotian civil war and Cambodian-Vietnamese war.

Indo-Pakistani Wars – When PT-76s sunk ships

The Indo-Pakistani wars of 1965 saw a full-scale attack of Indian troops, as a response to the Pakistani Operation Gibraltar, which involved instigating the local populations from Kashmir and Jammu against the Indian government. While tanks were used by both sides, mainly M4 Shermans, M36 Jacksons, and M24 Chaffees but also newer Patton tanks. India, on the other hand, used British Centurion tanks, M4 Shermans, and the brand new PT-76 tanks. Nonetheless, both sides were not very experienced with the use of AFVs in combat. For example, the 7th Light Cavalry, which was the first Indian unit to receive the tanks, only got them, in late August 1965. In September, crew instructions commenced, headed by 3 officers which were trained in the USSR. However, in the same month, they were ordered to intercept advancing Pakistani troops. The issue here was that Indian crews had just begun training and had little familiarization with the vehicles. In fact, the day they were to sight in their guns was the same day they were sent off to attack. Reportedly, the new tanks also caused confusion among other Indian troops, who mistook the tanks as Pattons or Pakistani tanks.

On 17th September, C squadron, detached from the 7th Cavalry, was advancing towards Chattanwala, when 7 PT tanks got bogged down. The unit commander’s tank had to be abandoned and was destroyed to avoid capture. The Pakistani East Bengal Rifles took the remains as a souvenir, but Indian troops recovered them in 1971.

Four days later, on the 21st, C Squadron encountered Pakistani M4 Sherman tanks and Pattons, near the village of Thathi Jaimal Singh, until Indian Centurions backed the light tanks up. The tanks engaged at close ranges of around 600 meters, but only one Indian PT-76 and two Pakistani tanks, an M4 and Patton were damaged, showing the poor usage and inexperience on both sides.

Pakistan captured a number of PT-76 tanks from India during the 1965 war, which ended inconclusively. Both sides more or less claimed victory, with a return to the state prior to the war, but with tensions at an all-time high.

Inevitably, war broke out again in 1971, after the Pakistani ‘Operation Searchlight’, a military operation that sought to crank down on the East Pakistan nationalistic movements, and resulted in the Bangladeshi Genocide. As a response, India stationed troops and military hardware near the border, including the 45th Cavalry Regiment and 69th Armored Regiment, both armed with PT-76 tanks. The border was separated by the rivers of the Ganges delta, making the PT-76 ideal for the location.

Consequently, on 21st November of the same year, in what is now known as the Battle of Garibpur, the 14th Punjab Battalion, consisting of 800 men, alongside 14 PT-76 light tanks belonging to the 45th Cavalry Regiment, entered areas of Garibpur (East Pakistani territory), with the mission of seizing and securing a road leading towards Jessore. Prior to the mobilization, there had been fights amongst the two nations’ border patrols, thus alerting to India’s plans. This allowed Pakistani forces to mobilize their military towards the respective areas, including an infantry battalion, and/or 107th Infantry Brigade for a total of 2,000 men, the 24th Independent Armored Squadron, 3rd Armored Squadron, and 3 additional armored squadrons equipped with M24 Chaffee light tanks. These tanks, while comparable in armor to the PT-76, were from the Second World War, and had worn out barrels and other components.

Major Daljit Singh Narag, commander of the C Squadron, part of the 45th Cavalry Regiment. He was killed by enemy machine-gun fire in his PT-76 hatch and awarded the Maha Vir Chakra.
Source: Honourpoint.in

The Indian PT-76 tanks were used to intercept the Pakistani counterattack, which began early in the day. They were able to gather intelligence on the Pakistani attack, allowing them to dig in the PT-76 tanks, recoilless rifles, and other equipment in the ground, for better protection, but seem to have left their positions to spearhead a counterattack against the Pakistani tanks. Despite being outnumbered 3 to 1 (though this claim might be exaggerated), the Indian tanks took advantage of the fog with the battle, seeing the incoming Pakistani forces from a mere 30 to 50 meters away. The Indian tanks were commanded by Major Daljit Singh Narag from his PT-76. He managed to destroy 2 Indian tanks before being killed by a fusillade of machine-gun fire when he was outside the hatch commanding his troops. He was awarded posthumously the Maha Vir Chakra, the second-highest military award in India.

Indian propaganda photograph showing a knocked out Pakistani PT-76. It is not entirely out of the question that this particular tank was actually Indian, as it has been misrepresented as a Chaffee.
Source: Seniorsday.in

In terms of losses, the sources conflict, claiming between 8 to 10 to even 14 Pakistani Chaffee tanks were destroyed and 3 captured (according to one source. in running condition) by Indian forces. Additionally, 300 Pakistani soldiers were killed and wounded. In terms of Indian losses, 28 were killed, 42 wounded, and 4 PT-76 tanks were lost.

Important to note is that the Battle of Garibpur happened before the war was even officially declared, and the Indian victory greatly boosted the confidence of Indian troops and decreased Pakistani morale. This disparity in morale is often said to be an important factor in following battles when the 1971 Indian-Pakistani war officially started.

In subsequent engagements in December of 1971, Pakistani troops had entrenched themselves in towns and cities. To combat this, the advancing Indian troops relied on Mi-4 Transport helicopters and PT-76 tanks to transport troops and equipment over the swampy delta, filled with bodies of water. However, in some instances, the PT-76 of the 5th Squadron bogged down, falling behind the infantry, and when attempting to cross a river, the hull sealings leaked, forcing them to go around on land.

Indian PT-76 tanks crossing a stream. Note the infantry hitching a ride.
Source: Medium.com

On 4th December, PT-76 tanks from the 1st Squadron defeated an infantry battalion defending the town of Mian Bazar. However, at this point, the thin armor proved inefficient against proper anti-tank equipment, losing 4 tanks to 106 mm recoilless rifles. On 9th December, the same unit overtook the docks in Chandpur, with Nepalese Gurkhas on top of the tanks. However, during the battle, three Pakistani gunboats engaged the amphibious tanks on the Meghna river. After a series of volleys and exchange of fire, all three boats were sunk and 180 sailors were rescued, out of the 540. Just two days later on 11th December, the tanks encountered another gunboat, which grounded itself, after being fired at with 54 shells from the main gun of the tanks. The tanks were then used as ferries, transporting troops and materiel to and from across the river, but there were instances where the engines overheated and required towing by nearby civilian boats. Note that the Meghna river is very large, and can be up to 1.5 km wide.

Simultaneously, on 9th December, tanks of A Squadron, 45th Cavalry attempted to occupy the town of Kushtia, however, were met by two platoons of M24’s, commanded by Major Sher Ur Rahman and an infantry company. They had used the raised terrain to cover themselves and offer a good overlook over the otherwise flat terrain. The Indian tanks pushed through the field until the Pakistani tanks opened fire. Two to four PT-76s returned fire, knocking out a Chaffee, but were, in turn, destroyed themselves. The lead tank (or last, depending on the source) started a full-throttle retreat, confusing and scaring the surrounding Indian infantry, who were using the tanks as cover, both physically and morally. However, the crews of the two tanks that had remained to fight were found shot dead with their limbs tied.

Two days later, the Indian troops were ready for a second attempt at taking over the town, but to their relief, Pakistani troops had retreated.

Indian PT-76 tanks on their way towards Dacca, the capital of East Pakistan.
Source: Medium.com

However, at times during the war, the PT-76 redeemed themselves, showing their worthiness when properly used. An example was when Indian advances were halted at Gobindaganj by well-positioned Pakistani troops, tanks, and artillery. To aid the troops, the 63rd Battalion used their PT-76 in a 55 km detour to flank the defending forces. This terrain was in no way forgiving, filled with bogs, swamps, and rivers, but the not-so-little PT’s were in their element. Exploiting the Soviet design, 12 Gurkha Nepalese troops were riding atop the tanks. The flanking maneuver was extremely successful, catching the Pakistani’s by surprise, knocking out one M24 Chaffee, a battery of 105 mm howitzers, and a detachment even set up a roadblock ambush for retreating forces, virtually encircling them.

The 45th Cavalry Regiment also continued their operations, swimming upstream the Bhairab (this is questionable, modern maps show this as geographically impossible unless a confusion in names or change of names) River, where they would intercept a ferry at Shyamganj, where around 3,700 fleeing Pakistani troops were captured. When the Regiment’s A Squadron crossed the Madhumati River, on the night of 14th December, 393 more prisoners were taken.

Two days later, on 16th December, the Pakistani forces surrendered, leading to the creation of the state of Bangladesh. While the PT-76 mostly met the very obsolete and worn out M24 Chaffee tanks, their correct use and full exploitation of its good amphibious capabilities, allowed the Indian military to fulfill tasks that no other vehicle could have done. A total of 30 such tanks were lost during the short war.

Prague Spring

The Prague Spring began in January of 1968 after Alexander Dubček was elected as First Secretary in the Communist Party of Czechoslovakia. He strived for decentralization from the Soviet Union, and encouraged more democratic reforms, loosening controls and restrictions on the media or freedom of speech. The main reform was the splitting of Czechoslovakia into the Czech Socialist Republic and the Slovak Socialist Republic.

Naturally, the Soviets were not too happy about these reforms, and during the night of the 20th and 21st August, invaded the ČSSR, with help from other Warsaw Pact nations – Poland, Hungary, and Bulgaria. It is worth noting that there were attempts by the USSR to reverse the reforms by Dubček, diplomatically, but to no avail. Around 200,000 troops alongside 2,000 AFVs invaded the country, according to the Washington Post. Despite the quick occupation, civilian sabotage and resistance continued for nearly 8 months, leading to around 137 dead and 500 wounded.

Two PT-76 Model 1952 on Na Poříčí street in Prague. Note the white stripes across the length of the hull and the width of the turrets.

Naturally, there were several PT-76 tanks present, but like other historians have noticed, documentation is scarce. All tanks, including PT-76 tanks, were painted with white stripes, one going across the hull and one, perpendicular to the previous, across the turret, forming a cross shape on the turret roof. This was done for aerial recognition in cities because, during the Battle of Berlin, many Allied aircraft mistook Soviet armor for German and shot them.

Arab-Israeli Wars

The Soviet light tank saw combat in the Middle East as well, with one of the better-documented conflicts being those between Israel and Arab nations, Syria and Egypt. Egypt first purchased PT-76 tanks in 1958, buying 50, followed in 1966 by another 50. Between 1970 and 1972, another 200 were bought. Egypt first used them during the Six-Day War, where they lost 29 such tanks.

Additionally, the IDF also captured 9 Egyptian PT-76 and some BTR-50 APCs and pressed them into service. The vehicles underwent some changes and modernizations, like the addition of a 4th crewmember, rearwards opening hatches, new radios, and roof-mounted machine guns. For some reason, these are often called PT-71, but that does not make much sense.

On 18th June 1969, the Israeli 88th Don Lavan unit was created, with PT-76 and BTR-50 tanks. However, the main issue was spare ammunition for the PT-76 tanks – only 1,950 rounds. These were used, for example during the War of Attrition. Then, on the night of 25th and 26th May 1970, 6 PT-76 and 7 BTR-50s attempted to cross the Timsah lake and attack the Egyptian place on the western shore. Even before entering the water, Egyptian forces spotted the Israelis, because 3 tanks got bogged down in the sandy shore, canceling the operation.

The PT-76 tanks were potentially used again during Operation Raviv, but that has yet to be confirmed. However, it is not entirely unlikely, as BTR-50 APCs had been used.

In 1971, the unit was moved to the reserves, with 9 PT-76 and 15 BTR-50 and 280 men, but was recalled in action at the start of the Yom Kippur war.

Egypt was to use the tanks again in 1973, this time vast numbers to cross the Suez Canal, as part of Operation Badr, in what would become the Yom Kippur war. Tensions had been building up for a long period of time, with Egypt rearming itself with state-of-the-art military equipment bought from the Soviet Union. Israel had intelligence that Egypt was rearming itself for war, but some Israeli officials considered it unlikely. Nevertheless, both Israel and Egypt conducted large-scale military exercises on either side of the canal. The attack was carried out between 6th and 9th October, while Syrian troops performed a simultaneous attack at the Golan Heights, also using PT-76 tanks.

Sources vary, claiming that Egypt assaulted with 90,000 to 100,000 troops, and 1,000 to 1,280 tanks, and 2,000 artillery. Meanwhile, Egypt carried out a heavy artillery bombardment against the Israeli bank. At 14:00, on 6th October 1973, 20 PT-76 tanks escorted 1,000 marine troops, riding inside BTR-50s. By 02:40 hours the next morning, the Egyptian troops were clearing minefields. The IDF only had 450 troops placed across the length of the canal, from the Jerusalem Brigade, backed up by only 1 armored brigade.

The Israeli tanks launched a counterattack but were beaten back by Egyptians who were equipped with RPGs and Sagger anti-tank missiles, which knocked out two tanks and 3 APCs. The Egyptian armored brigade then went on drive-by attacks against the Bir El Thamada air base and radar stations. The 603rd Marine Battalion, part of the brigade, then occupied Fort Putzer on the 9th.

The 602nd Battalion, consisting of 10 PT-76, was pushing eastwards, deeper into Israeli territory, when a battalion of 35 Israeli Patton tanks encountered them in the middle of the night. The Patton tanks used their xenon lights to effectively blind the Egyptian crews, wreaking havoc. Whatever tanks survived returned back.

When the Egyptian forces invaded, the 88th Don Lavan unit was flown to Sharm el-Sheikh, from where they had moved in position to engage Egyptian troops at Et-Tour. These were ordered to push forwards towards the Great Bitter Lake, but because they had to cross water bodies, they arrived late, at dawn on 16th October. They combined forces with a company of Magach tanks from the 79th Battalion and some infantry. The task was to intercept the Egyptian 25th Armored Brigade, towards the north of the lake. Later, another company of Magach tanks joined, also from the 79th Battalion. The PT-76 and Magach tanks offered a distraction, allowing for troops and tanks to flank the Egyptian tanks, annihilating them.

Israeli modified PT-76 tank, passing by a disabled Magach tank, Yom Kippur war.

On 14th October, the 88th and 14th Brigades, bringing with them 7 PT-76s and 8 BTR-50s, crossed into Egyptian territory, on the western bank of the Suez canal using pontoon bridges. Similar to the tactics employed during Operation Raviv, the tanks were painted in Egyptian colors and crews could speak Arabic. There, the units would participate in Operation Knights of Heart on the 15th of October. The main goal was to establish a bridgehead in the Egyptian territory, allowing for more troops to come in and turn the fighting from a defensive into an offensive campaign.

By the end of the war, the 88th was south of Ismailia. In June of 1974, the unit was disbanded. Many of their vehicles are now on display.

Chechen war

The Chechen war is one of the last conflicts where the PT-76 saw combat and were used from the very beginning. The tanks were mostly used in front of the infantry, protecting them from enemy fire. Likewise, they were also used in defense of roadblocks, strategic checkpoints, and various escorting missions. As an example, a PT-76 was seen near the Grozny Presidential palace.

Unit 3723 (one of the units known to have used PT-76 as a spearhead for infantry) is proof that the light tanks were also used in populated areas against Chechen militants. The unit was from Nalchik, and in December of 1994, entered Chechnya.

One of the few known photos showing a Russian PT-76B in the Chechen war.

On the 18th of April, 1995, Unit 3723 entered the town of Bamut. At least one PT-76 participated in the assault, commanded by Lieutenant Sergei Golubev. He made his way through all the way to the center of the town, alongside a T-72, commanded by Vyacheslav Kubynin. The battle lasted over two hours. Golubev’s PT-76 was quickly immobilized, while the T-72 was set on fire. Yet Golubev managed to extirpate one of the heavy machine gun nests situated in a building, thus covering the retreating Russian troops (the attack was unsuccessful). His tank was eventually destroyed, killing Golubev and his crew.

It was only after the battle it was remarked that, after an inspection of Golubev’s PT-76, the tank withstood 2 hits from RPGs and destroyed 3 enemy positions.

After the assault on Bamut, the unit commander, Alexander Korshunov, and Warrant Officer Alexander Maximov, recalled:

“We’re here from the very beginning of the Chechnya (campaign). Started at Chervlennaya, Vinogradnaya, Grozny. On February 18th, we left, returned, then came back again. Now Gudermes, Argun, Samashki and now – Bamut. (…)”
Korshunov, posthumously, was originally intended to be presented with the Order of Russia, but was awarded Order of Courage instead.

Two years after the end of the first Chechen war, in September of 1998, a PT-76 light tank battalion from the 8th Independent Brigade was dispatched to the city of Nalchik. These saw service in the second Chechen war, where crews, acknowledging the poor armor and vulnerability to RPGs, would add on improvised armor, like spare track links and rubber panels. Despite their obsolescence, their mere presence must have improved the morale of their own soldiers and frustrated the opponents.

PT-76 in the autumn (November likely) of 1999. Note the add on armor. These worked together with T-62 tanks.
Source: Armorama

One riot police officer recalled November 1999:

“With a tank, even though it’s light, you feel much more confident, than say, in a BTR of BRDM. After all, a 76 mm gun is much more hefty than a machine gun, even a heavy one. With suppressing (harassing) fire from the tanks, there were no attacks on us.”

A list made out of official reports covers around 50 to 60% of the official losses of Russian tanks during the wars, link to report here. Only one PT-76 is mentioned. This report is of exactly the PT-76 and T-72 from the assault of Bamut. There is also a possibility of a third tank, but that is unconfirmed. A video from the opposing militants from the 26th of April shows the two tanks. Aside from confirming the information above, it brings up the possibility that the T-72 was hit by an RPG from a school building and it caught fire.

The reports also give more information on the PT-76: After receiving two hits, it caught fire, disabling the gun. The tank then drove towards a mosque and rammed a tower, possibly a minaret, crashing the structure down. The commander, Golubev died under the rubble. However, according to Associated Press, the tank was close to the T-72 in an open area with no debris surrounding it. In the end, the entire crew died, consisting of Commander and gunner Lieutenant Sergei Golubev, loader Private A. Klimchuk and driver Private A. Kudryavtsev.

In the memoirs of K. Masalev, it is recounted how, during the retaking of Bamut, a PT-76 was found abandoned on a hill, clearly left by the Chechen forces. It is possible that it was Golubev’s tank, as there were no other PT-76 tanks used in the vicinity. It was blown up.

End of production and service

The light tank enjoyed a lengthy production run, starting in 1952 and ending in 1967, with a total of around 12,000 units built, out of which 2,000 were exported. Out of these, 4,172 were PT-76Bs, with 941 in turn, for export. In November 1990, there were still 602 PT-76 light tanks still in service in the European side of the USSR alone. After the dismantling of the USSR in 1991, a large portion of them went to the newly independent states. PT-76s would still see service as late as the Chechen wars in the 1990s, but so far, none in the war in Donbas.

With the start of production of the BMP-1, the PT-76 was redundant for the Soviets. Just as mobile and amphibious, with a new gun and most importantly, able to transport troops, this vehicle also made the PT-76’s brother, BTR-50, redundant.

After Russian equipment was withdrawn from Chechnya, in 2006, PT-76 tanks were all placed in the reserves of the Russian Defence Ministry, officially ending their active service in Russia.

Conclusion

The PT-76 was one of the many post-war tanks that were designed with WWII battles in mind, for a war that never happened. Yet it still is a more controversial tank than many others. On one hand, its obsolescence from the day it left the factories has been seen as its weakest side, with an outdated gun and paper-thin armor. On the other hand, its great water crossing capabilities and lower price compared to medium tanks or MBTs launched it into mass production and export success, with nations such as Syria buying them. Its practicality and design prompted the Chinese and North Koreans to produce tanks very similar to it. While it was not as high tech or capable of some of its contemporary Soviet vehicles, it proved that, when used as intended by its designers and Soviet doctrine, it was quite not as poor as it seemed.

Special thanks to Sebastien A. Robin for providing sources, Marisa Belhote for the segment on the M1981, and Hugo Yu for the section on the Muromteplovoz upgrade section.

PT-76
PT-76 model 1951, soviet naval infantry, in amphibious configuration, 1955.
East German PT-76
East German PT-76 model 1951, early 1960s
Finnish PT-76
Finnish PT-76B, 1960s.
NVA PT-76A
North Vietnamese PT-76A, battle of Ben Het 1969.
PT-71 PTRS Malyutka
PT-76 9M14 testing the Malyutka wire-guided missile system, 1970s.
PT-76
Polish Naval infantry PT-76B, 1980s.
PT-76
Indian PT-76B, Indo-Pakistani war of 1965, as displayed in Barhat war museum.
Egyptian PT-76
Egyptian PT-76B, war of 1967.
Syrian PT-76B
Syrian PT-76B of a reco unit, Golan heights, Yom Kippour 1973
Syrian PT-76B
A Syrian or possibly Egyptian PT-76B on display at Yad-La-Shiron museum, with the elevated trim vane.
IDF PT-76B
IDF PT-76B, fall 1970s.
North korean PT-76
Indonesian PT-76B.
PT-76
PT-76B from a Soviet naval infantry brigade, Yemen 1980.
Cuban PT-76B
Cuban PT-76B, Angola, 1980s.
Indonesia PT76B
Indonesian marine\’s PT-76B, 1990s
Iraqi 1990
Iraqi PT-76 B in 1990.
Croat PT-76 Slovenia
Croat P-76B.
Soviet Marines 1990
Late PT-76B, Soviet Marines, 1990s
PT-76B 1990
PT-76B Russian naval infantry, Baltic fleet 1990.
Russian Marines, Baltic fleet 1992
PT-76B, Russian naval infantry, Baltic fleet 1992.

Sources

PT-76B manual
PT-76 Light Tank They All Float | Medium
Tankograd: PT-76 (thesovietarmourblog.blogspot.com)
수륙양용 전차 PT-76 (1) : 네이버 블로그 (naver.com)
«Объект 907» и «Объект 906». Проекты развития ПТ-76 (topwar.ru)
https://www.history.com/this-day-in-history/soviets-put-brutal-end-to-hungarian-revolution
ARMOR: July – August 2012
Aresdifesa.it
Domestic Armored vehicles 1946-1965
Armor in Vietnam, Jim Mesko
PT-76 amphibious tank, Mikhail Borisovich Baryatinsky
Otvaga2004.ru
Kubinka tank museum
PT-76 light tank and variants, Christopher F. Foss
PT-76 tank | soldat.pro – military experts. unites the best!
Stories about weapons. The floating tank PT-76 outside and inside (topwar.ru)
India’s Armored Cavalry Rolled — And Swam — Into Bangladesh | by Sebastien A. Roblin | War Is Boring | Medium
PT-76 Light Amphibious Tank (enemyforces.net)
ArtOfWar. Понамарчук Евгений. Танковые потери федеральных сил в Первой чеченской войне
ОТЕЧЕСТВЕННЫЕ БРОНИРОВАННЫЕ МАШИНЫ 1945–1965 гг. (VI) « « Военно-патриотический сайт «Отвага» Военно-патриотический сайт «Отвага» (otvaga2004.ru)
As far as I know, PT-76E or PT-57 has never made it to serial production, only a few prototypes… | by Sergey Chernyshov | Medium
Военная продукция (muromteplovoz.ru)
Tactical missile system 2K1 “Mars” (topwar.ru)
M41 Walker Bulldog in combat – Mike’s Research
When Tanks Overran the Green Berets: The Battle of Lang Vei (warhistoryonline.com)
Танки ПТ-76 в боях на Северном Кавказе (vestnik-rm.ru)
Vor über 50 Jahren: Tödliche Spritztour auf dem Riewendsee (maz-online.de)
PT-76 – Kisah Tank Amfibi Tua TNI-AL (indomiliter.com)
Stockholm International Peace Research Institute (Sipri, Trade Registers)
ArtOfWar. Понамарчук Евгений. Танковые потери федеральных сил в Первой чеченской войне
Major Daljit Singh Narag MVC | Honourpoint
Battle of Garibpur: How did Indian PT-76 tank defeat American tanks in Pakistan? – Defence View
Не стреляйте в белых медведей. – Пещера злобного Буквоеда — LiveJournal
Last Stand At Lang Vei (Part One) | SOFREPs
PT-76 MLRS: Prototipe Tank MLRS Amfibi Marinir yang Terlupakan (indomiliter.com)
http://muromteplovoz.ru/en/product/mil_mod_pt76.php
Defense Intelligence Agency’s Soviet Navy Surface Ship Identification Guide (September 1982) DDB-1210-13-82
Советские мониторы, канонерские лодки и бронекатера by А. Платонов

Specifications PT-76*
*These details might vary depending on the production model year, check specific production model

Dimensions (L-W-H) 7,625 x 3,140 x 2,195 (prior 1957, 2,255 after 1957) m
Total Weight, Battle Ready 14.48 tonnes tonnes
Crew 3; driver, commander & loader
Propulsion V-6, 6 cylinder in-line, 4-stroke, water-cooled diesel, outputting 240 hp (179 kW) at 1800 rpm
Speed 44 km/h (27 mph) on road

10/11 km/h (6.2/6.8 mph) on water

Range X km
Armament 76.2 mm D-56T gun, later D-56TM or D-56TS

Coaxial 7.62 mm SGMT mg, later PKT

Armor 15 mm front turret & sides
8 mm upper hull¨front
13 mm lower hull front
15 to 13 mm on sides
6 mm rear
Total Production Circa 12,200

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