Germfask MI, M47 Patton – Military History of the Upper Great Lakes

In Germfask Michigan there is a tank on the side of the road. It is part of a monument in honor of Edward James Doran who served in WWII. The tank itself is a M47 Patton, which was designed for the Korean War.

History of M47

The M47 Patton was the result of severe time pressure on the U.S. Army to develop a competitive armored vehicle. Before the Korean War no tanks were in production, and the factories for World War II models had been converted back to civilan purposed long ago. In addition, the Army was in the process of converting 800 M26 Pershing tanks to M46 Pattons [9]. Not only did America not have tanks in production, but there was also a shortage of modern tanks available to the armed forces with the majority being M4 Shermans and M26 Pershings. Based on this, the War Department Equipment Board recommended that new tanks be developed in May 1946. This recommendation led to the start of development on several new tanks; however, progress was slow as the army was demobilizing in the years after WWII. According to Cameron, “the outbreak of the Korean War in 1950 added urgency to the Advisory Panel’s recommendations. Not only did the war catch the Army unprepared, the fear that it might become a global conflict highlighted the U.S. tank fleet’s weaknesses, both in numbers and quality” [5].

In order to meet the sudden demand for a new tank the Army had two options: One of these was to put WWII models back into production. This had the advantage of using well tested and understood designs; however, these tank models were very outdated and thus under armed and armored. The other option was to use a new design; but none of the designs in development were tested or standardized. Since both options would require the U.S. industrial base to retool for new production, the Chief of Staff and the Secretary of the Army decided to run the risk of producing the new tank models with out fully testing them and deal with issues in production [9]. This decision was spurred by the fact that the Army needed a new tank as soon as possible and did not want to wait the years it could take to finish designing and testing a new tank. “Since Speed was essential and the designing of the T42’s turret had been finished, it was deemed expedient to join the T42 turret to what basically had been the M46 hull” [1]. This combination is what became the M47 Patton. The new tank retained most of the speed and maneuverability of the M46, while mounting a much more effective gun. However, the Tank was not without its flaws. Among them, its range finder was difficult to use and the tank had severely limited range of only 85 miles. These problems, among other teething issues hampered its deployment in the Korean War and made it a less desirable vehicle. This was acceptable however as, the M47 was intended only as a stopgap measure until a superior medium tank design could be developed. Development of this replacement vehicle began in October 1950, before the first M47’s were delivered [5]. Despite this, over 9000 M47 tanks were built, with most being exported.

Evolution of tank design from WWII to Korea

At the end of the second world war the United States had three main tanks: The M24 Chaffee light tank, the M4 Sherman medium tank, and the M26 Pershing heavy tank. In the post war period these tanks were not considered to be ideal. According to Cameron, the M24 while well liked was under-armed with its main gun having little anti-tank capability [4]. The M4 Sherman, the most common American tank of the war was under-armed and under-armored. The M26 while well-armed and armored was under-powered. The groundwork for the development of the M26 began in 1943 due to questions about the armament of the M4. This started discussions about mounting a 90mm cannon on the M4 instead of its standard 75mm. However, Lieutenant General McNair, commander of the Army Ground Forces, considered this change unnecessary due to American doctrine which sait that tanks were not to be used to destroy enemy tanks but instead were for exploitation. [4]. This pressure caused development of improved tanks to proceed slowly. However, the Ordnance Department continued independent development of a heavy tank carrying the 90mm gun which resulted in the T26-series of heavy tanks [4]. This tank was standardized as the M26 Pershing and by the end of the war 200 had been shipped to Europe, though only 20 saw combat. When the war ended the Pershing was re-designated as a medium tank due to changing battlefield doctrine. Due to the Pershing’s roots as a heavy tank, it was under-powered and not well suited to the role as a medium tank.

While the Pershing was a significant improvement over the Sherman, it weighed significantly more and used the same power-train. In order to improve its performance, the Pershing was upgraded with the chief improvement being a new engine. In addition to improving power, these upgrades improved engine reliability and cooling [8]. This upgraded Pershing was renamed the M46 Patton which saw use in the Korean war. However, the in terms of armor and armament the Patton was essentially the same vehicle as the Pershing from WWII. In 1946, work began on a successor to the M46, the T42. However, due to the ongoing demobilization, work was slow until the Korean war broke out in 1950. At that time the T42’s turret carried an improved 90mm gun and was better armored compared to the M46. In addition it carried a stereoscopic range finder which had the potential to allow a better chance of a hit on the first shot. The T42’s engine however was unsatisfactory and underpowered [5]. With the war providing a strong need for a new design, the turret of the T42 was mounted on the hull of the M46 resulting in the M47 Patton. The M47 entered production in 1952 after a short testing period of testing, however, teething issues prevented it from entering active service during the war. The primary cause of these issues was the rangefinder which was complex and to fragile for use in a battlefield, in addition the turret control system frequently malfunctioned [5]. While these problems were eventually corrected, the M47 Patton was replaced by the M48 Patton in US service before it ever got to the front.

From the beginning the US Army recognized the M47 was less than ideal and never intended it as anything more than a stop gap measure. In 1950, while the M47 was being built, work started on an entirely new tank, which was developed into the M48 Patton. This tank was tested in 1952 and was a significant improvement over the M47. The M48 was a significant improvement over the M47, with improvements across the board. Its turret was more efficiently shaped allowing for better protection from incoming fire. It had a smaller four-man crew, and wider tracks, ensuring better traction and better distributing the weight of the tank to prevent it from sinking into mud. Additionally, the M48 fitted a much more powerful engine, providing better mobility. One of the most significant improvements was the addition of a mechanical fire control computer. This device calculated the range to target and elevated the gun based on range vehicle tilt and ammunition type, permitting engagements at much longer ranges than before.

Tanks in the Korean War

“On the eve of the Korean War, the Army had approximately 3,400 M24 [Chaffee] light tanks in the inventory, most of them unserviceable. In addition, there were available approximately 3,200 M4A3E8 Sherman medium tanks of World War II vintage, of which only a few more than half were serviceable” [8]. These tanks were holdovers from WWII and neither had been able to go head to head with a German tank, relying instead on numbers and tactics. However, at the start of the war these where the only tanks available for use in Korea, with the exception of a few M26 Pershings which were rushed over and suffered engine issues. While the M46 soon arrived, large numbers of Shermans and Chaffees remained on the front. During the Korean war the main adversary US tanks saw was the Russian made T-34. According to Thompson, who wrote about the war as it was happening, “the [M46] Patton, with a high velocity 90mm gun, was a match for the Russian made World War II T-34, while the lighter medium, the Sherman, with a souped up 76mm gun, was not quite in theT-34 class” [2]. Despite its seeming inferiority however, the Sherman still found use, in part because it was smaller and could more easily handle tight terrain and soft ground. One of the largest factor in how tanks perform is the way in which they are deployed. “In the beginning, the Korean War was a war of movement. U.S. tank units were assigned to various infantry divisions, regimental combat teams, and task forces for mobile fire support and antitank capabilities” [8]. However, when the Chinese and North Korean forces pushed back the war took on a much more defensive role for the US forces.

The war in which these tanks were used was different from the European war they were designed for. As Thompson stated, “there are few open areas where the tanks can be used en masse, and there have been no tank battles such as occurred on the Russian front or the western front in Europe. But in supporting infantry, tanks have been a good weapon against fortifications and on river crossings” [2]. Furthermore, the tanks had difficulty with the mountainous terrain and wet ground of Korea. Despite this, US tanks found uses primarily as infantry support. In Thompson’s words, “our own tanks, including Pattons, Shermans, and the light Chaffe with a 75 mm gun, have all been used in supporting roles which would look very strange to most tankers. While the ground was hard, we shoved tanks up mountain sides, as well as across rice fields. From mountain crests they fired into the enemy log bunkers” [2]. This is a significant departure from the traditional role of the tank in combat. While tanks have always supported infantry, usually the role of the medium tank is to break through enemy lines. Instead, Thompson describes tanks purely in the infantry support role. In fact, most tanks were used for indirect fire or used as fixed bunkers. After war analysis would show that this strategy worked and that the US tanks were about three times as effective as those fielded by the Koreans [8].

M47 details

The following information about the M47 Patton comes primarily from the tank manual and is may be interesting to some:

The Patton was 23 feet long by 11.5 feet wide and 9.6 feet tall, under combat load it weighed 48.6 tons. While this was significantly larger and heavier than the WWII era M4 Sherman, it was not much more than the M26 Pershing or the immediately preceding M46 Patton. The tank was powered by a 12-cylinder Continental Engine which produced over 810 hp resulting in 16.6 hp/ton resulting in a fair degree of mobility.

In terms of armor, the M47 had 4 inches of armor in the front of the hull set at a 60-degree angle. Because of this angle the armors effective thickness was doubled resulting in an effective 8 inches of frontal hull armor. The front of the turret also had 4 inches of steel armor but was not angled as sharply at only 40 degrees for an effective thickness of 5.2 inches.

The M47’s 90mm gun could fire many types of ammunition, from armor piercing (AP) to high explosive (HE), and more expensive discarding sabot (AP-DS) and anti-tank shaped charges (HEAT). The gun could also fire a selection of smoke and marker shells. In addition to the primary gun the M47 also had two .50 caliber machine guns on in the hull and one on the turret.

Schematic of the M47 Patton as seen in the tanks Manual. Picture taken from the AFV Database.

Despite the fact that the M47 Patton was a stopgap measure and was replaced before it ever saw combat, it was an important part of American tank design and lead to many other tank designs. The tank was designed in an era where the design of armored vehicles was changing to adapt to new technologies and contained man holdovers to older designs. One example of this is the five man crew. At the same time the M47 contained features which were new to American design, such as the turret which was shaped in a way to better prevent shells from penetrating it. Its immidiate predecessor, the M48 Patton, was used in the Korean War and was a vast improvement over the tanks in the American arsinal at the time.

Primary Sources

Secondary Sources

Further Reading

“M47 Patton,” Wikipedia