Anti-tank potential and post-war service of the ISU-152 self-propelled gun
About Soviet self-propelled vehicles artillery SU-152 and ISU-152 installations, armed tank modification of the 152-mm howitzer-gun mod. 1937, there are many myths, and in domestic literature dedicated to the events of the Great Patriotic War, these machines are often called "Zveroboys". Authors who extol the anti-tank potential of heavy self-propelled guns with a 152-mm gun forget why these machines were created, and also lose sight of the direct fire range and rate of fire.
Of course, the enemy did not have serial tanks and self-propelled guns capable of withstanding a 152-mm shell. But as the course of military operations in the east of Ukraine shows, direct hits from 152-mm HE shells are equally successful in inflicting heavy damage or destroying both our MBTs and modern Western-made tanks. This does not mean that modern 152-155-mm self-propelled and towed howitzers were created specifically to fight tanks, although, of course, armored vehicles appearing within artillery range are among the priority targets.
Before we begin the story about the ISU-152 self-propelled gun, it would be logical to mention the previous model – the SU-152, the reasons for the appearance of these vehicles and their role on the battlefield.
After almost all of the KV-2 heavy assault tanks with 152mm howitzers were lost in defensive battles at the start of the war, the military for some time forgot about heavy self-propelled guns. The reason for this was the negative experience with the overweight KV-2, which in fact, despite having a turret, was a self-propelled gun. In addition, there was no particular need for a heavy self-propelled assault gun when conducting defensive actions. However, after the transition to offensive combat, the armored units of the Red Army needed qualitatively new models of equipment.
Taking into account the existing experience of operating the SU-76M and SU-122, the question arose of creating assault self-propelled guns armed with large-caliber guns. Such self-propelled guns were primarily intended to destroy capital fortifications when breaking through well-prepared enemy defenses. During the planning of offensive operations in 1943, it was expected that Soviet troops would have to break through long-term deeply echeloned defenses with concrete pillboxes. Under these conditions, there was a need for a heavy self-propelled gun with weapons similar to the KV-2. However, by that time, the production of 152-mm M-10 howitzers had ceased, and based on the unsuccessful experience of operating the KV-2, installing a gun of such a caliber in the turret was considered impractical. After analyzing all the factors, the designers came to the understanding that from the point of view of obtaining acceptable weight and size characteristics, placing a large-caliber gun in an armored cabin on a combat vehicle is optimal. The elimination of the turret allowed for an increase in the volume of the fighting compartment, a reduction in weight, a reduction in the cost of the vehicle, and better habitability.
The design of a new self-propelled gun armed with a 152 mm ML-20S gun, a tank modification of the very successful 152 mm howitzer-gun mod. 1937 (ML-20), began in the second half of 1942. Work proceeded at a rapid pace, and by the end of January 1943, the Chelyabinsk Kirov Plant (ChKZ) had completed the construction of the first prototype of the SU-152 heavy self-propelled gun. The KV-1S heavy tank served as the base for the new self-propelled gun. The layout of the self-propelled gun was the same as that of most Soviet self-propelled guns of that time.
One of the prototypes of the SU-152
In terms of protection, the SU-152 was almost identical to the KV-1s tank. The thickness of the frontal armor of the cabin was 75 mm, the front of the hull was 60 mm, and the sides of the hull and cabin were 60 mm. The combat weight was 45,5 tons. The V-2K diesel engine with a power of 500 hp accelerated the self-propelled gun on the highway to 43 km/h, and the speed on the march on a dirt road did not exceed 25 km/h. Cruising range on the highway was up to 330 km. Crew - 5 people.
The gun had a horizontal firing sector of 12° and elevation angles from -5 to +18°. The ammunition load included 20 separate-case loading rounds. During the rate-of-fire tests, it was possible to achieve a rate of fire of 2,8 rounds/min. But the real combat rate of fire did not exceed 1-1,5 rounds/min. The firing range for visually observed targets reached 3,8 km. The maximum firing range was 6,2 km.
The first batch of 14 serial vehicles was delivered in February 1943. On February 14, 1943, simultaneously with the adoption of the SU-152, the State Defense Committee issued Resolution No. 2889 "On the formation of heavy self-propelled artillery regiments of the RGK", but the SU-152 did not begin to enter service until April. Much time was spent on eliminating production defects and "teething problems". In addition, based on the results of the first use at the front, it turned out that when firing, a large volume of powder gases accumulated inside the fighting compartment, which led to the loss of the crew's ability to work. To solve this problem, it was necessary to intervene with the top management, after which two fans were installed on the roof of the fighting compartment.
Initially, the TSAP had 6 batteries with two installations in each. Subsequently, based on the experience of combat operations, the organizational and staff structure of the TSAP was revised in the direction of unification with the staff of the regiments armed with SU-76M and SU-85. According to the new staffing schedule, the TSAP now had 4 batteries with three SPGs in each, the number of personnel in the regiment was reduced from 310 to 234 people, and the command platoon was introduced with a KV-1s "commander's" tank and a BA-64 light armored car.
At the first stage, the Soviet command did not fully understand how to use heavy self-propelled guns, and they tried to use them in the same way as artillery regiments armed with 152-mm ML-20 howitzer-guns. However, the SU-152 had a shorter firing range, and the imperfection of the radio stations installed in the vehicles made it difficult to control the fire, prevented normal communication with forward artillery observers, and most often the SU-152 gunners fired at visually observed targets. During the offensive, the self-propelled guns usually supported tanks with fire, moving behind them at a distance of 600-800 m, fired direct fire at enemy fortifications and destroyed firing points.
In defense, heavy SPGs were used as roving guns, firing at the attacking enemy from cover or moving out to direct fire. Very often, the SU-152 acted as an anti-tank reserve. Thus, the tactics of the TSAP differed little from the tactics of the SAP, which had self-propelled guns of other types, but the effectiveness of firing at manpower and fortifications, due to the greater destructive effect of the 152-mm shell, was higher than that of 76-122-mm self-propelled guns.
After the first months of operation, comments began to come in from the active army. Serious complaints were made about the visibility from the fighting compartment, since the periscope devices had large areas of unseen space, which often became the cause of vehicle losses. There were many complaints regarding the small ammunition supply. The troops practiced increasing the ammunition supply from 20 to 25 rounds by placing an additional 5 rounds under the gun. The shells and charges of the additional ammunition supply lay on the floor, secured with homemade wooden blocks. Loading new ammunition was a labor-intensive and physically difficult operation, taking more than 30 minutes. The presence of a fuel tank inside the fighting compartment, in the event of an enemy shell penetrating the armor, often became the cause of the death of the entire crew.
Nevertheless, of the first three Soviet assault self-propelled guns launched into serial production after the start of the war, this machine turned out to be the most successful. The SU-152, unlike the SU-76, had no obvious defects in the engine and transmission group. In addition, the fighting compartment of the self-propelled gun, built on a more balanced chassis of the KV-1S heavy tank, was more spacious than on the SU-122. The design of the combat vehicle itself, equipped with a very powerful 152-mm gun, turned out to be quite successful. Serial production of the SU-152 continued until January 1944. A total of 670 self-propelled guns of this type were delivered. The SU-152 was most actively used at the front in the period from the fall of 1943 to the summer of 1944.
The SU-152s were used against enemy armored vehicles in mid-1943 near Kursk, where two TSAPs were stationed. From July 8 to July 18, the 1541st TSAP reported destroying 7 Tigers, 39 medium tanks, and 11 self-propelled guns of the enemy. In turn, the 1529th TSAP destroyed and knocked out 8 tanks (including 4 Tigers) and 2 self-propelled guns on July 7. During the battle on the Kursk Bulge, the SU-152s, moving behind the tanks, provided them with fire support and fired from closed firing positions. Only high-explosive fragmentation shells were used for firing; armor-piercing shells were not available at that time. Due to the fact that there were few direct clashes with German tanks, major losses were avoided. Only 24 heavy self-propelled guns took part in the battle sporadically and they did not have much of an impact on the course of military operations.
In the reports on the results of combat operations, among the armored vehicles destroyed by the SU-152 crews, the Tiger heavy tanks and Ferdinand tank destroyers are repeatedly mentioned. However, if we add up all the requests for the destruction of enemy heavy tanks and self-propelled guns received from the active army, it turns out that our tank crews and artillerymen destroyed several times more Tigers and Ferdinands than were produced. In most cases, this happened not because someone wanted to take credit for non-existent merits, but because of the difficulty of identifying enemy armored vehicles on the battlefield. German medium tanks Pz.Kpfw. IV of late modifications, equipped with long-barreled guns and anti-cumulative screens mounted on the side of the hull and turret, changed their appearance beyond recognition and began to resemble the heavy Tiger, and since the summer of 1943, the Red Army called all German self-propelled guns with a rear-mounted fighting compartment "Ferdinands". The Germans also had a very well-established service for evacuating damaged tanks from the battlefield. Quite often, "Tigers" "destroyed" in Soviet reports were successfully restored in field tank repair shops and went into battle again.
As for the protection of the SU-152 itself, by mid-1943 it no longer fully corresponded to the current realities of the Soviet-German front. The frontal armor of the SU-152 could be penetrated by the 75-mm Pak. 40 anti-tank gun and the Kw.K.40 L/48 tank gun from a distance of 1000 m.
Creation, release and structure of units equipped with the ISU-152 self-propelled guns
In parallel with the launch of the IS-85 heavy tank into serial production, the question arose of creating a heavy self-propelled artillery unit on its basis, armed with a 152-mm ML-20S gun. The ISU-152 self-propelled gun was developed by the design bureau of the experimental plant No. 100 and officially entered service with the Red Army on November 6, 1943. However, a considerable period of time passed from the moment of its adoption until its appearance in the active army. Due to the overload of production capacities, at first the new self-propelled gun was produced in very small quantities, and for some time the well-mastered SU-152 was assembled in parallel.
ISU-152
Serial production of the ISU-152 was carried out at the Chelyabinsk Kirov Plant (ChKZ) and the Leningrad Kirov Plant (LKZ). In 1943, ChKZ delivered 35 ISU-152 to the military, and in 1944 – 1340 self-propelled guns; by the end of May 1945, 1885 vehicles had been built.
The ISU-152, along with the SU-152 and ISU-122, were sent to form heavy self-propelled artillery regiments. From May 1943 to 1945, 53 TSAPs were formed. Each regiment had 4 batteries of 5 SPGs. The command platoon also had an IS-2 tank or the regiment commander's self-propelled gun. In December 1944, the formation of guards heavy self-propelled artillery brigades began to provide fire support for tank armies. Their organizational structure was borrowed from tank brigades, the number of vehicles in both cases was the same - 65 self-propelled guns or tanks, respectively.
When designing the ISU-152, the experience of combat use and operation of the SU-152 was taken into account, and the developers tried to get rid of a number of design flaws. During the production process, changes were made to the design of the self-propelled gun aimed at improving combat and operational qualities and reducing the cost. After eliminating the "teething problems", the ISU-152 proved itself to be a very reliable and unpretentious machine.
One of the priorities was to increase the protection of the combat vehicle. Compared to the SU-152, the ISU-152's armored hull was slightly higher and had a larger internal cabin volume, which provided better working conditions for the crew.
The front of the hull and the wheelhouse were covered with 90 mm of armour. The thickness of the upper part of the side of the hull and the wheelhouse was 75 mm, the lower part of the side of the hull was 90 mm. The gun mantlet was 100 mm. In the second half of 1944, the construction of self-propelled guns with a welded front part of the hull from rolled armour plates instead of one solid cast part began, the thickness of the gun armour mantlet was increased to 120 mm.
The ISU-152's armor protection could not reliably withstand armor-piercing shells fired from the 8,8 cm Pak. 43 towed anti-tank guns, the 8,8 cm KwK. 36 L/56 and 8,8 cm Kw.K. 43 tank guns, and the 8,8 cm FlaK. 18/36/37/41 anti-aircraft guns. However, the frontal armor successfully withstood hits from the 800 mm Pak. 75 anti-tank gun and the Kw.K.40 L/40 tank gun at a distance of over 48 m.
Much attention was paid to increasing the reliability and service life of the engine, transmission and chassis. The V-2-IS diesel engine with a maximum power of 520 hp could accelerate a 46-ton vehicle to 30 km/h on the highway. The speed on a dirt road usually did not exceed 20 km/h. Cruising range on the highway was up to 250 km.
The main armament, sighting devices and crew composition remained the same as on the previous model. But compared to the SU-152, the crew's working conditions and visibility from the vehicle became better.
Vehicles produced from the end of 1944 were armed with a 12,7 mm DShK anti-aircraft machine gun and had increased capacity of internal and external fuel tanks.
The large-caliber anti-aircraft machine gun, mounted on the right round hatch of the vehicle commander, had 250 rounds in five boxes.
At the final stage of the war, the enemy aviation rarely tried to bomb and storm our armored vehicles, but the 12,7 mm anti-aircraft machine gun mount proved to be very useful in street fighting.
Combat use of the ISU-152 during World War II
Although in Soviet and Russian military mythology the ISU-152 is considered our strongest tank destroyer, the real anti-tank potential of this vehicle is not as good as it is sometimes written about.
By the time the TSAPs were sufficiently saturated with ISU-152s, enemy tanks began to appear on the battlefield less frequently, and the heavy self-propelled guns were mainly used for their intended purpose - to destroy permanent firing points, make passages in obstacles, and provide fire support for advancing troops.
At the same time, as soon as enemy tanks appeared in the gunner's field of vision, they immediately became the primary target. A direct hit from a 53-BR-540 armor-piercing shell weighing 48,9 kg resulted in the guaranteed destruction of any enemy tank, regardless of the firing distance.
Tank Pz.Kpfw. V Panther after being hit by a 152 mm shell
Another thing is that with an initial projectile velocity of 600 m/s, the direct fire range was 800 m, and the combat rate of fire did not exceed 1,5 rounds/min. In a duel situation, the crew of the Tiger or Panther had a much better chance of winning than the 152-mm SPG. In fairness, it should be said that the Soviet command understood this and tried to use the ISU-152 against enemy tanks from ambushes.
There are many examples of successful firing at armored vehicles with 152 mm high-explosive fragmentation shells at a distance of more than 3000 m. In this case, the enemy was usually fired at by several self-propelled guns. With a direct hit on an enemy tank, even if the armor was not penetrated, it was likely to receive heavy damage. A close explosion disabled the chassis, armament, and optics. Having come under fire from 152 mm high-explosive fragmentation shells, enemy tanks in most cases hastily retreated.
Under equal conditions, in direct confrontation with enemy armored vehicles, the SU-152, SU-85, and SU-100/122S demonstrated much greater effectiveness than the ISU-122. Thus, the much cheaper SU-85 self-propelled gun, built on the T-34 chassis and armed with an 85-mm gun, was capable of firing up to 6 rounds per minute. At a distance of 800 m, an 85-mm armor-piercing shell with a fairly high probability penetrated the frontal armor of the Tiger. At the same time, the silhouette of the SU-85 was lower, and its mobility was better.
Heavy self-propelled guns, when used with proper tactics, suffered fewer losses than tanks, but during the offensive they sometimes encountered anti-tank artillery and 88-105 mm anti-aircraft guns operating from well-camouflaged positions, as well as German heavy tanks and tank destroyers.
The first ISU-152s appeared at the front in March 1944. During the whole of 1944, 369 vehicles were irretrievably lost, most of them fell victim to towed guns, were lost as a result of the impact of rocket-propelled grenades, or were blown up by mines. Considering that not all vehicles produced in 1944 participated in combat, the level of losses was approximately 25% of the original composition.
Heavy self-propelled guns were very effective in urban combat. A hit by a 152 mm shell with a high explosive fuse in a two-story brick city house usually resulted in the collapse of the floors and interior walls. After the explosion of a 53-OF-540 shell, weighing 43,56 kg and containing almost 6 kg of TNT, only half-destroyed outer walls often remained of the building. Thanks to the relatively short barrel of the ISU-152 self-propelled gun, it was quite easy to maneuver on the narrow streets of European cities. In the same conditions, it was much more difficult for the drivers of the SU-85, SU-100, and ISU-122 self-propelled guns to operate.
However, in urban conditions, when the firing range was often several tens of meters, the ISU-152, like all other tanks and self-propelled guns available to the Red Army, was very vulnerable to infantry anti-tank weapons.
The ISU-152 was rarely used as a self-propelled howitzer during the Great Patriotic War. This is explained by the difficulty of controlling the self-propelled gun's fire, as well as the fact that when firing from closed positions, the self-propelled gun was inferior to the ML-20 towed howitzer-gun with a maximum vertical guidance angle of 65°. With an elevation angle of 20°, the 152-mm ML-20S gun could not fire at steep trajectories, which significantly limited the scope of the ISU-152. The supply of shells from the ground during firing was difficult, which negatively affected the practical rate of fire. The ISU-152 demonstrated its best efficiency precisely in the role of an assault artillery mount, firing at visually observed targets. In this case, the consumption of shells when performing the same task was many times less than when the self-propelled gun fired from a closed position.
After the capitulation of Nazi Germany, the TSAP, which included ISU-152s, took part in military operations against Japan.
The ISU-152 self-propelled guns were actively used to breach fortified areas in Manchuria. By September 3, 1945, a dozen and a half vehicles were lost or seriously damaged by Japanese heavy artillery fire, falling from heights on mountain roads and bridges, being blown up by mines, and as a result of suicide attacks.
Post-war use of ISU-152
The production of the ISU-152 continued until 1947, and 1357 units were delivered in the post-war period. Unlike the ISU-122, armed with the "122-mm self-propelled gun mod. 1931/44", self-propelled units with the 152-mm ML-20S gun, built in 1944-1947, were mostly not put into storage, but were actively used in combat units until the mid-1970s, until the troops were completely saturated with the new generation of self-propelled guns.
Compared to the ISU-122, self-propelled guns armed with a 152-mm gun were converted into tractors, repair and recovery vehicles and mobile launchers for operational-tactical weapons. missiles slightly altered. In the post-war period, the ISU-152 was modernized to the level of the ISU-152M and ISU-152K.
The ISU-152M modification received upgraded units and chassis of the IS-2M tank, a DShKM anti-aircraft machine gun with 250 rounds of ammunition and night vision devices. The old radio stations and TPUs were replaced by R-113 radio stations and R-120 TPUs. More efficient fans were installed, removing powder gases from the fighting compartment.
In the second half of the 1950s, at the same time as the major repairs of the self-propelled guns, the LKZ was converting them into ISU-152K. This modification was radically different from the original version.
A commander's cupola with a TPKU device and seven observation blocks was installed on the roof of the wheelhouse. The ammunition load was increased to 30 rounds, which required changing the layout in the fighting compartment and introducing additional mounts for shells and charges. An improved PS-10 telescopic sight was installed instead of the ST-10 sight. Some vehicles were equipped with new R-123 radio stations. The DShK anti-aircraft machine gun was replaced with a modernized DShKM with an ammunition load increased to 300 rounds. The ISU-152K was equipped with a V-54K engine with a capacity of 520 hp. The lubrication system was improved, and the radiator design also changed. The capacity of the fuel tanks increased to 1280 liters, due to which the cruising range reached 360 km. Elements of the T-10 heavy tank were used in the chassis. The weight of the self-propelled gun increased to 47,2 tons, but the dynamic characteristics remained the same.
Fifteen years after the end of production, the armor protection of the ISU-15 was no longer so good at protecting against anti-tank weapons of a potential enemy. In this regard, the 152-mm self-propelled guns largely lost their assault functions. The main task of units equipped with the ISU-152 was to provide fire support for attacking tanks. At the same time, according to the new concept of using self-propelled guns, their appearance directly on the battlefield was not envisaged in most cases. More attention was paid to firing from closed positions, although the problem of feeding shells from the ground was never solved.
In the post-war period, the ISU-152 was not only used in maneuvers, but also participated in combat. Heavy self-propelled guns were actively used during the suppression of the anti-communist uprising in Hungary in 1956. Heavy 152-mm shells, as in the storming of German cities, very effectively destroyed firing points in buildings and demolished barricades blocking streets.
At one stage the fighting was very intense, and there is evidence that several ISU-152s were damaged and even captured by the rebels.
The modernized 152-mm self-propelled guns were used for a long time in all regions of the USSR; they were even used by artillery units of the Marine Corps and practiced landing on the coast from large landing ships.
According to available information, the ISU-152 served in the artillery division of the 55th Marine Division of the Pacific fleet until 1983 year.
By the mid-1980s, some of the decommissioned self-propelled guns were cut up for scrap or used as targets at tank ranges and artillery shooting ranges.
However, a considerable number of ISU-152s in acceptable technical condition were sent into storage and also used in various types of tests and experiments.
ISU-125
For example, the 125mm 125A2 smoothbore tank gun was tested on the installation known as the ISU-46.
Several ISU-152s were used to eliminate the nuclear accident in Chernobyl. These machines were transferred to Pripyat from a storage base in Novomoskovsk, Dnipropetrovsk Oblast. A number of authors claim that the ISU-152s were planned to be used to shoot a hole in the casing of the damaged fourth power unit, after which a hose was supposed to be pulled through it to supply liquid nitrogen under the foundation slab.
In reality, self-propelled guns near Chernobyl were used as heavy tracked tractors, as well as for demolishing buildings with ramming attacks.
According to eyewitnesses, there were three self-propelled guns in the radioactive zone in 1986. Two of them were abandoned in the vicinity of Pripyat, the fate of the third is unknown.
The Soviet Union also transferred heavy self-propelled guns to its allies. After the end of World War II, approximately two dozen ISU-152s were used by the Polish Army until the late 1960s.
The Czechoslovak army had several SPGs. Most of them were mothballed in the second half of the 1950s. But one disarmed vehicle was used at a tank range to test anti-tank obstacles and as a heavy tractor. In the 1980s, the Czechs used the chassis of several SPGs to create the ISU Bulldozer heavy bulldozers.
In Finland, one of the two ISU-1944s captured in the summer of 152 was used after the war. During repairs, this self-propelled gun was converted into a tractor, designated Ps.745-1, which was used until 1964.
Ps.745-1
Subsequently, the gun was returned to this self-propelled gun and it was installed in the tank museum in Parola, where it remains to this day.
Romania received 24 ISU-152s in the early 1950s. These self-propelled guns, designated T-152, served in the artillery units of the 6th, 7th, and 57th Tank Divisions of the Romanian Army until the late 1980s.
In 1955, the Soviet Army, leaving the territory of the PRC, left 67 ISU-152 self-propelled guns to the PLA. According to reference data, in the early 1990s, China still had 45 vehicles in storage.
Several ISU-152s took part in the Korean War. After the armistice, North Korea received up to fifty heavy self-propelled guns. They may still be in reserve. Western sources write that at least one vehicle was used in the implementation of the DPRK missile program.
In the first half of the 1960s, the USSR transferred more than 20 ISU-152 to Egypt. The Egyptians used them in 1967 as fixed firing points.
Several serviceable ISU-T self-propelled guns and tractors were captured by the Israeli army; one ISU-152 is currently on display at the armored museum in Latrun.
There were some number of heavy 152mm self-propelled guns of Soviet manufacture in Iraq.
The Iraqi army reportedly tried to use the self-propelled guns to repel the American invasion in 2003. There is a photo online of one ISU-152 destroyed near the city of Fallujah. Apparently, the ammunition detonated inside the self-propelled gun, and the powerful explosion tore off the conning tower.
To be continued ...
Information