Tank

: This article is about armoured fighting vehicles. For other meanings, see Tank (disambiguation).

Protection

The main battle tank is the most heavily armoured vehicle in modern armies. Its armour is designed to protect the vehicle and crew against a wide variety of threats. Commonly, protection against kinetic energy penetrators fired by other tanks is considered the most important. Tanks are vulnerable to antitank guided missiles. Antitank mines, larger bombs, and direct artillery hits can also disable or destroy a tank. Tanks are especially vulnerable to airborne threats. Most modern MBTs do offer near complete protection from artillery shrapnel and lighter antitank weapons such as rocket propelled grenades. The amount of armour needed to protect against all conceivable threats from all angles would be far too heavy to be practical, so when designing an MBT much effort goes into finding the right balance between protection and weight.

Related Topics:
Kinetic energy penetrator - Antitank guided missile - Mines - Bomb - Artillery - Rocket propelled grenades

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Armour

Most armoured fighting vehicles are manufactured of hardened steel plate, or in some cases aluminium. The relative effectiveness of armour is expressed by comparison to rolled homogeneous armour.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Most armoured vehicles are best protected at the front, and their crews always strive to keep them pointed in the likeliest direction of the enemy. The thickest and best-sloped armour is on the glacis plate and the turret front. The sides have less armour and the rear and roof are least protected. World War Two American Sherman tank crews found the German Tigers to be practically invulnerable from the front, and were forced to employ flanking tactics to take them out. Today, tanks are vulnerable to specialized top-attack missile weapons and air attack, and even a Molotov cocktail on the engine deck is bad news for any tank.

Related Topics:
Glacis - Turret - Top-attack - Molotov cocktail

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Before the Second World War, Soviet tank designers started to slope the armour on several tanks, most famously the T-34. Angling armour plates greatly increases their effectiveness against projectiles, by increasing the effective perpendicular thickness of the armour, and by increasing the chance of deflection. German tank crews were said to be horrified to find that shots fired at T-34s would sometimes simply bounce off.

Related Topics:
Slope the armour - T-34

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Even light infantry antitank weapons can immobilize a tank by damaging its suspension or track. Many tracked military vehicles have side skirts, protecting the suspension.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

High explosive antitank weapons (HEAT), such as the bazooka, were a new threat in the Second World War. These weapons carry a warhead with a shaped charge, which focusses the force of an explosion into a narrow penetrating stream. Thin plates of spaced armour, steel mesh "RPG screens", or rubber skirts, were found to cause HEAT rounds to detonate too far from the main armour, greatly reducing their penetrating power.

Related Topics:
High explosive antitank - Bazooka - Shaped charge - Spaced armour - RPG

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Some antitank ammunition (HESH or HEP) uses flexible explosive material, which squashes against a vehicle's armour, and causes dangerous spalling of material inside the tank which may kill the crew without penetrating the armour. As a defence, some vehicles have a layer of anti-spall material lining their insides.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Since the 1970s, tanks have been protected by more complex perforated or composite armour, a sandwich of various alloys and ceramics. One of the best types of passive armour is the British-developed Chobham armour, which is comprised of spaced ceramic blocks contained by a resin fabric matrix between layers of conventional armour. A form of Chobham armour is encased in depleted uranium on the massively protected M1A1 Abrams MBT.

Related Topics:
Composite armour - Alloy - Ceramic - Chobham armour - Resin - Fabric - Matrix - Depleted uranium - M1A1 Abrams

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

The Israeli Merkava tank takes the design of protection systems to an extreme, placing the engine and even the fuel between the crew and the direction of likely incoming fire.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Grenade launchers, smoke and passive defences

Most armoured vehicles carry smoke grenade launchers which can rapidly deploy a smoke screen to visually shield a withdrawal from an enemy ambush or attack. The smoke screen is very rarely used offensively, since attacking through it blocks the attacker's vision and will give the enemy an early indication of impending attack. Modern smoke grenades work in the infrared as well as visible spectrum of light.

Related Topics:
Grenade launcher - Smoke screen - Grenade - Infrared - Visible spectrum

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Some smoke grenades are designed to make a very dense cloud capable of blocking the laser beams of enemy target designators or range finders and of course obscuring vision, reducing probability of a hit from visually aimed weapons, especially low speed weapons, such as antitank missiles which require the operator to keep the tank in sight for a relatively long period of time. In many MBTs, such as the French-built Leclerc, the smoke grenade launchers are also meant to launch tear gas grenades and anti-personnel fragmentation grenades. Many Israeli tanks contain small vertical mortar tubes which can be operated from within the tank, enhancing the anti-personnel capabilities and allowing it to engage targets which are behind obstacles. There have been proposals to equip other tanks with dual-purpose smoke/fragmentation grenade launchers that can be reloaded from the interior.

Related Topics:
Leclerc - Tear gas - Mortar

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Prior to the widespread introduction of thermal imaging the most common smoke grenade in AFV launchers was white phosphorus which created a very rapid smoke screen as well as having a very useful incendiary effect against any infantry in the burst area (e.g., infantry attempting to close with hand placed charges or mines).

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Since the advent of thermal imagers most tanks carry a smoke grenade that contains a plastic or rubber compound whose tiny burning fragments provide better obscurant qualities against thermal imagers.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Some tanks also have smoke generators which can generate smoke continuously, rather than the instantaneous, but short duration of smoke grenades. Generally smoke generators work by injecting fuel into the exhaust, which partially burns the fuel, but leaves sufficient unburned or partially burned particles to create a dense smoke screen.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Modern tanks are increasingly being fitted with passive defensive systems such as laser warning devices, which activate an alarm if the tank is "painted" by a laser range-finder or designator.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Other passive defences include radio warning devices, which provide warning if the tank is targeted by radar systems that are commonly used to guide antitank weapons such as a millimetre and other very short wave radar.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Countermeasures

Passive countermeasures, like the Russian Shtora system, attempt to jam the guidance systems of incoming guided missiles.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Explosive reactive armour, or ERA, is another major type of protection against high explosive antitank weapons, in which sections of armour explode to dissipate the focussed explosive force of a shaped charge warhead. Reactive armour is attached to the outside of an MBT in small, replaceable bricks.

Related Topics:
Explosive reactive armour - High explosive antitank - Shaped charge

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Active protection systems go one step further than reactive armour. An APS uses radar or other sensing technology to automatically react to incoming projectiles. When the system detects hostile fire, it calculates a firing resolution and directs an explosive-launched counter-projectile to intercept or disrupt the incoming fire a few metres from the target.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Exposed crew

Paradoxically, a tank is usually in its safest state when the commander is in a personally unsafe position, riding in the open, head out of the turret, with no personal protection save his helmet and a flak jacket. In this rather high position the commander can see around the vehicle with no restrictions, and has the greatest chance of spotting enemy antitank operations or natural and unnatural obstacles which might immobilise or slow down the tank. Tank periscopes and other viewing devices give a sharply inferior field of vision and sense of the countryside, despite constant advances in optics and electronics. Thus, when a tank advances in hostile territory with hatches closed, the commander and the crew might be personally safer, but the tank as a whole is more at risk given the extremely reduced vision.

Related Topics:
Commander - Helmet - Flak jacket - Periscope

~ ~ ~ ~ ~ ~ ~ ~ ~ ~