tank destroyer,

thinly armoured military vehicle mounted with a weapon capable of engaging and disabling tanks

from beyond the maximum effective range of main tank guns. Tank destroyers were produced

and employed in great numbers during World War II; at that time their weaponry consisted of a

high-velocity antitank gun. Modern tank destroyers are armed with antitank guided missiles.

During World War II tank destroyers were deployed mainly by the armies of the United States,

Germany, and the Soviet Union. They were less complex and easier to produce than tanks,

consisting in most cases of a suitable tank chassis mated to an adaptable antitank gun. For

instance, the American M10A1 Gun Motor Carriage, a tank destroyer known as the Wolverine,

went into production in 1942. It was based on the same chassis used to produce the M4

Sherman tank. Mounted on this chassis was a fully traversible open-top turret housing a 3-inch

high-velocity gun. In 1944 the 3-inch gun was replaced by a more powerful 76-millimetre gun.

This improvement made the vehicle capable of destroying later model German tanks. The M10

weighed 33 tons, had a maximum speed of 30 miles (50 kilometres) per hour, and could travel

200 miles on a load of fuel. It was operated by a crew of five. Its armour ranged in thickness

from a maximum of 37 millimetres (1.5 inches) to a minimum of 12 millimetres. In 1943 the U.S.

Army attempted to up-gun the M10 by mounting a 90-millimetre gun in the turret. The effort

failed, and a new turret was designed to accommodate the larger gun. The resulting new model

was designated the M36; it was capable of defeating German Panther and Tiger tanks while

maintaining a comfortable stand-off distance.

The US Army employed 60 battalions of tank destroyers during World War II. They were used

in offensives to destroy enemy armour and in infantry attacks as assault guns. They also were

used to augment the firepower of tank battalions and were employed as roving artillery batteries.

Through the lend-lease program to aid the Unites States' allies, the Americans provided the

British with M10s. The British up-gunned the vehicle, replacing the 3-inch gun with a British

17-pound gun. This improvement made the tank destroyer more lethal, and it extended the

service life of the vehicle in the British army beyond World War II.

The Germans, like the Americans, combined existing components (i.e., chassis and guns) to

develop and produce tank destroyers. The chassis came from the Panzerkampfwagen (Pz.) III,

IV (Panther), and VI (Tiger) tanks, and the guns were adapted from various models of the

famous 88-millimetre antiaircraft "FlaK" and antitank "PaK" guns. The German Panzerjäger

Nashorn ("Rhinoceros") tank destroyer, for instance, was built on the Pz. IV chassis. It had a

maximum speed of 25 miles per hour, a range of 160 miles, and a crew of five. The main gun

was fully enclosed in a lightly armoured superstructure that did not rotate; the gun could traverse

30°. The Rhinoceros depended on range and accuracy to survive; in close-quarter engagements

it was at considerable disadvantage because of its thin armour.

During the war German armoured vehicles tended to increase in size. They became more heavily

armed and armoured, increasing in range of fire and survivability while decreasing in mobility,

agility, and range of travel. An example of this trend can be seen in the Panzerjäger Elefant

("Elephant"), based on the monstrous Pz. VI Tiger tank chassis. Its 128-millimetre antitank gun

was mounted in a fixed housing. The hull had a maximum front armour of 200 millimetres and

side armour of 80 millimetres, making the Elephant one of the most lethal and survivable

armoured vehicles on World War II battlefields. The main gun could traverse 24°, and the

vehicle had a maximum speed of 12.5 miles per hour, with a range of 60 miles. The Elephant

carried a crew of six.

The Soviets, too, adapted existing technology to produce tank destroyers. Soviet models were

built on the chassis of the T-34 tank. Various large-calibre guns were mounted in fixed housings.

As World War II progressed, tank guns grew larger, and their muzzle velocities increased. This

increased the range and accuracy of tanks, thus eroding the relative advantage of the tank

destroyers. In addition, the tank destroyers' thin armour made them considerably less survivable

than tanks. As a result of these advances in tank technology, the effectiveness of tank destroyers

diminished throughout the war, prompting the U.S. Army in Europe to recommend that tank

destroyers "be replaced by a tank which can equal or outgun enemy tanks and which has

sufficient armor to protect itself and its crew from normal anti-tank and tank weapons." In the

decades after the war, gun-armed tank destroyers were abandoned. However, the development

of precision-guided munitions have encouraged a few armies to develop and deploy

missile-armed tank destroyers. Like their gun-armed World War II forebears, these vehicles

frequently have matched an existing chassis--e.g., from a tank or infantry fighting vehicle--to a

current-model antitank guided weapon. An example is the German Jagdpanzer Jaguar, a fully

tracked vehicle armed with American TOW or French HOT antitank missiles. Employed in

mechanized infantry units, the vehicle is able to keep up with fast-moving infantry fighting vehicles

and also provide some measure of defense against enemy tanks.