M36 tank destroyer

U.S. combined arms doctrine on the eve of World War II held that tanks should be designed to fulfill the role of forcing a breakthrough into enemy rear areas. Separate GHQ tank battalions would support infantry in destroying fixed enemy defenses, and armored divisions would then exploit the breakthrough to rush into the enemy's vulnerable rear areas. U.S. tanks were expected to fight any hostile tanks they encountered in their attack, but the mission of destroying massed enemy armored thrusts 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 (charging or chasing enemy tanks was explicitly prohibited) to destroy 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.

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 yards. This was foreseen, however, and in late summer 1942 American engineers had begun analyzing the potential of 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. Mounting 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 numbers 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 1 June 1944 as the 90 mm Gun Motor Carriage M36.

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. This conversion lasted from April to July 1944. The contract was later increased to 500 vehicles, as it was decided that existing M10A1s were also to be converted to M36s. 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. The 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 was converted 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 further batch of 52 M36B2s was completed by the Montreal Locomotive Works in May 1945.

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

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 tank destroyer battalions attached to armored divisions. The 703rd Tank Destroyer Battalion began reequipping on 30 September 1944. The Third US Army used them to reequip towed battalions. The 610th Tank Destroyer Battalion (Towed) began retraining on 25 September 1944.[3] 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 Panther at 4,600 yards, the maximum range of the telescopic sight. However, the Panther's 82 to 85mm thick glacis plate[4] could deflect certain shots from the 90 mm gun at just 150 yards, and the 150mm thick front armor of the Tiger II could only be penetrated in a few hard-to-hit places.[5][6] By the end of 1944, seven tank destroyer battalions had converted to the M36. The M36 had 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.[7]

M36s were also exported after World War II to various countries. It was used by the French army during the First Indochina War, and they were supplied as part of U.S. military aid to Pakistan in the 1950s and served in the Indo-Pakistani War of 1965. One recipient was Yugoslavia, which received 399.[8] The engine was later 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 were withdrawn immediately from service with the Croatian Armed Forces 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 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.

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.[9] 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 in (9.5 to 127.0 mm).

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

• 90 mm Gun Motor Carriage T71 (Prototype): 90 mm gun turret on 3-inch Gun Motor Carriage M10A1 hull. Turret redesigned and standardized as M36
• 90 mm Gun Motor Carriage M36: 90 mm gun turret on 3-inch Gun Motor Carriage M10A1 hull
• 90 mm Gun Motor Carriage M36B1: 90 mm gun turret on M4A3 Sherman hull and chassis.
• 90 mm Gun Motor Carriage M36B2: 90 mm gun turret on 3-inch Gun Motor Carriage M10 hull

• 17pdr SP Achilles
• G-numbers
• M-numbers

• "United States' M36, M36B1, M36B2 Tank Destroyers", World War II Vehicles, Tanks, and Airplanes, www.wwiivehicles.com, archived from the original on 2007-12-15, retrieved 2009-06-15
• Standard Military Motor Vehicles. dated 1 sept. 1943
• TM9-745 90mm Gun Motor Carriage M36B2, 1945 at archive.org
• TM9-748 90-mm Gun Motor Carriage M36B1, 1945 at archive.org
• TM 9-758 90-mm Gun Motor Carriage T71 (M36 GMC)
• TM 9-374 90MM Gun M3 Mounted in Combat Vehicles at archive.org
• Tankdestroyer.net (website with United States tank destroyer forces information resource)
• Chamberlain, Peter; Ellis, Chris (1969), British and American Tanks of World War Two., London: Cassell & Company
• Green, Michael (2014), American Tanks & AFVs of World War II, Oxford: Osprey Publishing
• Mesko, Jim (2003), US Tank Destroyers, Walk Around Number 5703., Carrollton: Squadron/Signal
• Zaloga, Steven (2002), M10 and M36 Tank Destroyers 1942-1953, New Vanguard, Book 57, Oxford: Osprey Publishing
• Yeide, Harry (2007), The Tank Killers: A History of America's World War II Tank Destroyer Force., Drexel Hill: Casemate Publishing

Wikimedia Commons has media related to M36 Tank Destroyer.

• AFV Database
• OnWar
• FM 18-18 Crew Drill, Gun Motor Carriage, M36