M36 tank destroyer

90 mm Gun Motor Carriage M36
Type Tank destroyer
Place of origin United States
Production history
Designer U.S. Army Ordnance Department
Designed 1943
Manufacturer General Motors
Massey-Harris
American Locomotive Company
Montreal Locomotive Works
Unit cost $51,290 (M36)
Produced April–August 1944
October–December 1944
May 1945
Number built 2,324 (all models)
Variants See Variants
Specifications (90 mm Gun Motor Carriage M36[1])
Weight 63,000 lb (28.6 metric tons)
Length 19 ft 7 in (5.97 m) hull
24 ft 6 in (7.47 m) including gun
Width 10 ft 0 in (3.05 m)
Height 10 ft 9 in (3.28 m) over antiaircraft machine gun
Crew 5 (Commander, gunner, loader, driver, assistant driver)
Armor 0.375 to 5 in (9.5 to 127 mm)
Main
armament
 90 mm gun M3
47 rounds
Secondary
armament
 .50 caliber (12.7 mm) Browning M2HB machine gun
1,000 rounds
Engine Ford GAA V8; 450 hp (336 kW) at 2,600 rpm
Power/weight 15.2 hp/metric ton
Transmission Synchromesh
5 speeds forward, 1 reverse
Suspension Vertical volute spring suspension (VVSS)
Fuel capacity 192 US gallons (727 litres)
Operational
range
 150 mi (240 km)
Speed 26 mph (42 kph) on road

The M36 tank destroyer, formally 90 mm Gun Motor Carriage, M36, was an American tank destroyer used during World War II. The M36 combined the hull of the M10 tank destroyer, which used the M4 Sherman's reliable hull and drivetrain combined with sloped armor, and a massive new turret mounting the 90 mm gun M3. Conceived in 1943, the M36 first served in combat in Europe in October 1944, where it partially replaced the M10 tank destroyer. It also saw use in the Korean War, able to defeat any of the Soviet tanks used in that conflict. Some were supplied to South Korea as part of the Military Assistance Program and served for years, as did re-engined examples found in Yugoslavia, which operated into the 1990s. Two remained in service with the Republic of China Army at least until 2001.

American soldiers usually referred to the M36 as a "TD", an initialism of "tank destroyer".[2]

Doctrine

US combined arms doctrine on the eve of World War II held that tanks should be designed to fulfill the role of supporting infantry in forcing a breakthrough, and then exploiting the breakthrough to rush into the enemy's vulnerable rear areas. The anti-tank warfare mission was assigned to a new branch, the Tank Destroyer Force. Tank destroyer units were meant to counter German blitzkrieg tactics. Tank destroyer units were to be held as a reserve at the corps or army level, and were to move quickly to the site of any massed enemy tank breakthrough, maneuvering aggressively and using ambush tactics to destroy enemy tanks. Tank destroyers were explicitly not supposed to charge or chase enemy tanks. This led to a requirement for very fast, well-armed vehicles. Though equipped with turrets (unlike most self-propelled anti-tank guns of the day), the typical American design was more heavily gunned, but more lightly armored, and thus more maneuverable, than a contemporary tank. The idea was to use speed and agility as a defense, rather than thick armor, to bring a powerful self-propelled gun into action against enemy tanks.

Design

90 mm GMC M36 during the Battle of the Bulge in January, 1945.

With the advent of heavy German armor such as the Panther and Tiger, the standard U.S. tank destroyer, the M10 tank destroyer, was rapidly becoming obsolete, because its main armament, the 3-inch gun M7, had difficulty engaging these new tanks frontally past several hundred metres. This was foreseen, however, and in late summer 1942 American engineers had begun analyzing the potential of the designing a new tank destroyer armed with a 90mm gun. This study resulted in a prototype vehicle, the 90 mm Gun Motor Carriage T53, which placed the 90 mm gun in an open mounting at the rear of an M4 Sherman chassis. In August 1942, it was agreed to immediately produce 500 vehicles, with 3,500 more later. The Tank Destroyer Force objected, arguing that the design of the T53 was too rushed. The 90 mm Gun Motor Carriage T53E1 proved to be even worse, and the entire contract was canceled.

In October 1942, the Ordnance Department tested mounting the experimental 90 mm gun T7 into the turret of an M10 tank destroyer. General Andrew Bruce, head of the Tank Destroyer Force, objected to the project, favoring the M18 Hellcat, but was ignored. The mounting of the 90 mm gun was straightforward, but the gun proved too heavy for the M10's turret. A new turret was designed that incorporated power traverse and a massive counterweight to balance the gun. The first two M36 prototypes, designated 90 mm Gun Motor Carriage T71 were completed in September 1943. Initially, a request for full production was denied as 90 mm guns were already being studied for use on tanks, but Army Ground Forces approved the project in October 1943, and tests began. The ring mount on the left side of the turret for the .50 caliber Browning M2HB antiaircraft machine gun was changed to a pintle mount at the rear. It was decided that production vehicles would use the chassis of the M10A1 tank destroyer, as significant amounts of M10A1s were available, and it was determined that the M10A1 had superior automotive characteristics. After testing, an initial order for 300 vehicles was issued. The T71 was designated upon standardization on June 1, 1944 as the 90 mm Gun Motor Carriage M36

Production

After July 1943, the appliqué armor bosses on the hull side of the M10A1 were deleted as the armor kits were never manufactured. This meant that some M36s had the redundant bosses, while others did not. The M36 initially retained the M10A1's "stirrup" gun rest on the rear hull; crews were unhappy about the lack of a proper travel lock for the 90 mm gun, and many improvised their own from travel locks taken from tanks. As the massive muzzle blast of the 90 mm gun obscured the crew's vision and reduced the rate of fire, a double-baffle muzzle brake was fitted to all vehicles after the first 600, beginning in early November 1944. A proper folding travel lock better-suited to the 90 mm gun was added to the rear hull at about this time. The gun itself was also modified with a better equilibrator and more powerful elevating mechanism.

As the initial contract was for 300 vehicles, General Motors' Fisher Tank Arsenal produced the last 300 M10A1 tank destroyers in January 1944 without turrets for immediate conversion to M36s. The contract was later increased to 500 vehicles, as it was decided that existing M10A1s were also to be converted to M36s. Conversion of the 300 M10A1 into M36 at Fisher Tank Arsenal lasted from April to July 1944. The requirement was later increased to 600 vehicles on May 15, 1944. As it was found that the M10 tank destroyer had struggled against German tanks like the Panther and especially the Tiger during the Normandy campaign the contract was increased to 1,400 vehicles on July 29, 1944. This caused problems, as only 913 of the 1,413 M10A1s that had been completed could be requisitioned from training units. Due to the lack of M10A1 hulls, it was decided to finish up the initial production run by mounting M36 turrets onto M4A3 Sherman hulls, with the necessary internal changes. Production of 187 90 mm Gun Motor Carriage M36B1 ran from October to December 1944. From June to December 1944, Massey-Harris converted 500 M10A1s into M36s. From October to December 1944, American Locomotive Company converted 413 M10A1s into M36s. The Army reduced the 1,400-vehicle objective for 1944 to 1,342 vehicles. 350 more conversions were scheduled for 1945; this number was increased to 584. A final batch of 200 M10A1s were converted into M36s by the Montreal Locomotive Works in May 1945.

The supply of M10A1s eventually ran out, so it was decided in January 1945 that M10 hulls would be used for all further conversions. American Locomotive Company converted 672 M10 hulls into the 90 mm Gun Motor Carriage M36B2 beginning in May 1945. A batch of 52 further M36B2 was completed by the Montreal Locomotive Works in May 1945.

Production of M36, M36B1, and M36B2[3]
Month M36 M36B1 M36B2
April 1944 25
May 1944 100
June 1944 120
July 1944 155
August 1944 100
September 1944
October 1944 75 50
November 1944 290 93
December 1944 348 44
January 1945
February 1945
March 1945
April 1945
May 1945 10 50
Post-war 190 674
Total 1,413 187 724

Armor

American tank destroyer doctrine emphasized speed and gun power over armor. As the M10 and M36 were not purpose-built tank destroyers (they were based on tank chassis) they were not as fast as the Tank Destroyer Force wanted. General Andrew Bruce criticized the M36 due to it being too slow.[4] The armor configuration of the M36 was identical to that of the M10A1, save the turret. The thickness of the M36's armor ranged from 0.375 to 5.0 inches (9 to 127 mm)

Hull

The lower hull had 1 inch (25 mm) thick armor on the sides and rear. The rounded, cast transmission cover was 2 in (51 mm) thick. Like the M10, the M36 lacked the extra 0.5 in (13 mm) floor plate under the driver's and assistant driver's stations that provided them additional protection from mines. The glacis plate was 1.5 in (38 mm) thick, sloped at 55 degrees from the vertical, and had eight large bosses on it in order to attach appliqué armor plates. The sides and rear of the upper hull were 0.75 in (19 mm) thick, sloped at 38 degrees from the vertical. Depending upon the production period of its M10 parent, each side of the M36's upper hull was plain, or could be adorned with 12 appliqué armor bosses. The rear upper hull plate was used for storage of the vehicle's pioneer tools; a 5-pound (2.27 kg) axe, a 5-foot (1.5 m) crowbar, a mattock handle and head, and a double-sided 10-pound (4.54 kg) sledgehammer. The track tensioning wrench was also stowed there. As a result, there were no appliqué armor bosses there regardless. The sides and rear of the upper hull featured angled extensions or covers over the upper run of track. These extensions often got in the way of fitting "duckbill" extended end connectors, used to reduce ground pressure on soft ground, and were often removed, along with the front fenders, by maintenance units. The hull roof plate ranged from 0.75 in (19 mm) thick over the driver's and assistant driver's stations and turret ring, to 0.38 in (9 mm) thick over the engine compartment.

The M36B1 had the hull armor configuration of the late production M4A3 Sherman tank.

Turret

The sides of the M36's rounded turret were 1.25 in (32 mm) thick, constructed of rolled armor plate. A massive hollow cast counterweight was welded to the rear of the turret to balance the heavy gun. The top was 0.38 (9 mm) to 1 in (25 mm) thick, and the sides were 1.25 in (32 mm) thick. The rear was 1.75 in (44 mm) to 5 in (127 mm) thick. The rounded cast gun shield was 3 in (76 mm) thick.

Armament

Primary

The M36 tank destroyer used an M10A1 chassis (the M36B1 used an M4A3 Sherman chassis, while the M36B2 used an M10 chassis) mounting a large, open-topped turret mounting a 90 mm gun M3. The gunner aimed the gun using the M76F telescope. The 90 mm gun M3 was the standardized version of the experimental T7, a derivative of the 90 mm gun developed as a vehicle-mounted antitank weapon. The M36 carried 47 rounds of main gun ammunition. 11 rounds were stowed in the hollow counterweight, while 36 rounds were stowed in the sponsons. For combat use, the 90mm gun M3 could fire 5 types of ammunition:

The M82 armor-piercing capped shot was the main round used for engaging enemy tanks. It had a large explosive filler to increase damage after penetration. It was capable of penetrating 129 mm of armor angled at 30 degrees from the vertical at 500 yards (457 m) and 122 mm of armor at 1,000 yards (914 m) The T30E16 HVAP shot was capable of penetrating 221 mm of armor angled at 30 degrees from the vertical at 500 yards, and 199 mm of armor at 1,000 yards.[5] The T30E16 HVAP round had difficulty with the highly sloped glacis plate of the German Panther tank, so the T33 AP shot was developed to solve this problem. The T33 shot was a normal substitute standard M77 armor piercing shot that was heat-treated to improve its hardness and fitted with a ballistic "windshield" to improve its drag characteristics.[6] The T33 and T30E16 were only issued in very small numbers towards the end of World War II. The M71 high explosive shell was used for indirect fire, or engaging enemy infantry, antitank guns, light vehicles, or other soft targets.

Secondary

The M36 tank destroyer was equipped with a single .50 caliber (12.7 mm) Browning M2HB machine gun for antiaircraft or antipersonnel use, along with 1,000 rounds of ammunition. Because of the difficulty in firing the .50 caliber machine gun directly to the front, the pintle was often repositioned to the front of the turret, or a .30 caliber (7.62 mm) Browning M1919A4 machine gun mounted there. The M36B1 retained the bow machine gun of the M4A3 Sherman tank, and had 2,000 rounds of ammunition for it. The crew had their personal weapons for self-defense.

Combat use

The first 40 M36s did not make it overseas until September 1944, and entered combat in October 1944. The First and Ninth US Armies used M36s to reequip battalions attached to armored divisions. The 703rd Tank Destroyer Battalion began reequipping on September 30, 1944. The Third US Army used them to reequip towed battalions. The 610th Tank Destroyer Battalion (Towed) began retraining on September 25, 1944.[7] The first tank destroyer battalion to actually receive the M36 in early September, The 776th, was in transit from Italy to Europe at the time and did not use them in combat until October 1944. The M36 was well-liked by its crews, being one of the few armored fighting vehicles available to US forces that could destroy heavy German tanks from a distance. Corporal Anthony Pinto of the 1st Platoon, Company A, 814th Tank Destroyer Battalion knocked out a Panther at 4,200 yards. Another 814th gunner, Lt. Alfred Rose, scored a kill against a panzer at 4,600 yards, the maximum range of the telescopic sight. However, the Panther's glacis plate could deflect certain shots from the 90 mm gun at only 150 yards, and the front armor of the Tiger II could not be penetrated at all.[8] By the end of 1944, seven tank destroyer battalions had converted to the M36. The M36 mostly replaced the M10 by the end of the war.

After World War II, the M36 was used in the Korean War. It could destroy any Soviet-made AFV deployed in that theater of operations. One postwar modification was the addition of a ball-mounted machine gun on the co-driver's side, as in many other armored fighting vehicles of the time. Due to the shortage of M26 and M46 tanks, the M36 became one of the preferred armored vehicles for MAP (Military Assistance Program) transfers. South Korean tank battalions were provided with 110 M36s (along with a small number of M10 tank destroyers) during the Korean War.[9]

M36s were also exported after World War II to various countries. One of the recipients was Yugoslavia where the engine was replaced with the 500 hp Soviet-made diesel engine used in T-55 main battle tanks. Yugoslavian M36s participated in the Croatian War of Independence (1991–1995) but they are no longer in service with the Croatian Armed Forces due to their withdrawal immediately after the war. M36s were also used by Serbian forces in Bosnia and Croatia, and they were used during the Kosovo War as decoys for NATO air strikes. The M36 was used by the French army, during the First Indochina War. They were also supplied as part of U.S. military aid to Pakistan in the 1950s and served in the Indo-Pakistani War of 1965.

The Republic of China Army acquired eight ex-French examples in 1955 and had them stationed in Kinmen island group, where they were deemed more maneuverable than the bigger M48A3 and later CM11/12 MBTs while being more powerful than M24 and M41 light tanks. As of April 2001, at least two still remained in service with troops in Lieyu Township.

Variants

90 mm Gun Motor Carriage M36B2 on display at the Military Museum of Southern New England in Danbury, Connecticut.

Operators

See also

Notes

  1. ↑ http://afvdb.50megs.com/usa/90mmgmcm36.html#M36
  2. ↑ Keegan, John (1979). World armies (2 ed.). Macmillan. ISBN 0-333-17236-1.
  3. ↑ Zaloga (2002) p21
  4. ↑ Zaloga (2002) p19
  5. ↑ Zaloga (2002) p19
  6. ↑ Green (2014) p191
  7. ↑ Yeide (2010) p175
  8. ↑ Yeide (2010) p174-175
  9. ↑ Zaloga (2002) p.42

Sources

External links

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