A Brief History and Examination of the modern Tank

One of Jane's Fighting Nodes.

Tanks are an essential part of twentieth century military history. Few major ground conflicts have occurred in which they were not a factor, even if only in their potential deployment. This node aims to answer a few common questions about tanks, vis: What are they? Where did they come from? How do they work? What are they used for? How does one kill them?

What are they?

Tanks are armored ground vehicles that travel on a tracklaying chassis (also known by its most visible characteristic, treads), and mount weapons designed to engage other vehicles of their own class (at a minimum) as well as be as lethal as all hell to anything on the battlefield smaller or less protected than themselves. Tanks do come in various sizes, from light tank all the way up to the behemoths known as Main Battle Tanks.

Although fearsome in capability, tanks are not without several glaring and well-known vulnerabilities. First of all, they are extremely large, heavy and in most cases relatively slow-moving. This means that, barring other factors, hitting a tank with an aimed weapon once you've gotten a good look at it isn't a large problem. Therefore, designers and operators of the things have had to come up with various means to ensure that you don't get that good look, or that even if you do hit it, it doesn't care.

Second of all, because they're large and heavy, tanks are limited in where they can travel. A modern MBT can weigh as much as 75 tons and measure in at 8 meters by 5 meters! Running one of these through a cramped cityscape isn't possible unless you're trying to knock the city down as you go. This sometimes is the case. See Grozny for a recent example. However, in a more frequent problem area, tanks are limited to strong bridges and large transport vehicles, meaning bodies of water such as large rivers or lakes can cause real trouble for them. They are extremely difficult (although not impossible) to move by air.

Third, modern tanks are extremely complex machines, are require an enormous amount of routine (and, unfortunately, sometimes not-so-routine) maintenance in order to remain operational. They cannot typically be used to travel long distances; in between actual engagements (and sometimes during protracted ones) tanks must be carted about on large trucks or railway cars. At any given moment, a significant number of these large expensive and crucial assets may be out of service. They also, therefore, require a huge logistical tail to keep running, with a steady flow of fuels, lubricants, ammunition, spare parts, etc.

Fourth, tanks suffer from their very success. By their nature and due to their deadly capabilities, tanks are regarded as primary targets on any battlefield on which they appear. This results in an amusing dichotomy between tank crew and infantry - tankers profess to not understand why you'd want to be on a battlefield without several inches of high-grade armor around you, and infantry profess to not understand why on earth you'd want to spend all your time inside a high-visibility target, methods of whose destruction have spawned entire industries and technologies.

Where Do They Come From?

Tanks are the illegitimate children of the First World War (or World War I, if you prefer). During that conflict, for reasons which are legion, the combatants (essentially all of Europe save the Swiss plus other victims) had managed to work themselves into a complete battlefield stalemate, and had been reduced to staring at each other across several hundred yards of charnel house no man's land, engaging in frequent artillery duels, harrassing attacks, and in several particularly tragic cases, massive infantry assaults against prepared positions and automatic weapons. For more information, see The Somme, Passchendaele, and any history of that war.

In any case, the root cause of the problem (as far as I can tell) was that doctrine had not caught up with available technology, in this case, the automatic weapon. Why this was so has occupied many scholars for many years. Rather than adjust doctrine, which the BEF Command had proved most reluctant to do no matter what the cost (see the above battles), the British military decided to apply technology to the problem in turn. Drawing on the newly-available technology of the internal combustion engine, as well as those same automatic weapons that were making life so difficult (and death so easy), they set out to create what they envisioned as a 'land dreadnaught' - a concept quite natural in a nation so historically linked with ocean-going armored deathdealers.

In point of fact, the concept of the tank had been around in (ta daa!) science fiction for some time (yes, there was sci-fi then!). H.G. Wells, of War of the Worlds fame, had envisioned land dreadnaughts and fighting aeroplanes and aeropiles in his most excellent book When the Sleeper Wakes. Jules Verne, that master of technological prognostication, had predicted land ships with cannon. Reality was about to catch up.

The name 'tank', as RyanP has noted, came from a British Army security deception. During the development of the tank, they were naturally most anxious to prevent word of these new weapons from leaking out. Unable to completely hide the enormous metal shapes that were now lurking around the periphery of their research establishments and military bases, they took to officially referring to them as 'water tanks' - a metal object of plausibly similar size - in order to deflect curiosity. The name stuck.

In any case, they managed to develop and deploy their new creations in relative secrecy, and the tanks proved immensely capable at their primary purpose, which was to be moving pillboxes. Essentially, the tank was designed to permit the movement of machine guns from place to place without making them vulnerable to other machine guns, so that you might drive across that aforementioned killing ground between the trenches and pour machine-gun fire into the other sides' machine guns from above them (avoiding their trench and sandbag defenses) without, yourself, getting riddled with bullets.

The problem was that the British hadn't really thought much past the stage of 'okay, so we get through their trenches...' and the tank was too slow and unreliable to progress much past the front lines without significant infantry support, which *was* vulnerable to defending fire. Also, they ran up against what many have claimed was the primary cause of the trench-fighting of the War - logistics simply hadn't caught up with the increasing demands of a machine-age military. Armies now needed (in addition to food, water, and hay) bullets, parts, artillery shells, flares, barbed wire, entrenching tools, construction supplies for said trenches and bunkers, fuel for cooking as well as vehicles, medicine, etc. etc. However, the motorized transport of the day was not plentiful nor reliable enough to even begin to be able to provide transportation of these needs; as a result, army supply and troop transport still relied on railroads. The real question, then, became how far one could operate from the railhead; at that point, armies were still limited by the range of draft transport (horses, mules, etc). This range is limited by the fact that the animals must carry food for their own consumption as well as their intended load; above a certain distance (forty miles, perhaps) the demands of the animal's hunger overmatch its total carrying capacity - and the conflict had assured that there was very quickly no native grass or other feed left for the beasts even before the poison gas attacks began.

As a result, although the tanks breached enemy trench fortifications fairly easily, the Allies were unable to develop their breakthrough, and other than shifting the trenches by a few miles, not much came of it operationally. However, the fire had been lit, and those who had seen them and rode in them carried with them, out of the conflict, the seeds of what would become probably the fiercest tank war of all, the Second World War.

How do they Work?

Early tanks were fairly simple, containing large internal combustion engines and armor plate hung on an oversized chassis. The primary innovation on the early tank was the tracklaying system, or treads. This solved the problem of getting across soft, broken or outright barricaded ground. The tracks themselves mean that the average tank's ground pressure is much lower than a car, despite their much higher total weight. Therefore, they won't sink into soft ground nearly as easily; and even if they do, the huge amount of traction that comes from a grip surface the whole length of your vehicle means they can pull free fairly easily. Essentially, the only thing that will stop a tank other than a wall it can't either go over or punch through is deep water...and some tanks can either ford such obstacles or float across them.

The problems came once opponents got over their shock and started pointing larger caliber weapons at the tanks. Machine guns were never really a problem for main battle tanks; however, medium-weight guns that weren't much use in distance duels suddenly became popular for tankbusting. Probably the most famous of these is the German 88-millimeter antiaircraft gun that the Wehrmacht possessed going in to the Second World War. It was light and portable (for a cannon), it traversed and pitched easily, having been designed to track and follow aircraft, and it fired a fairly solid shell at great speeds, having been designed to throw those same shells long distances almost straight up into the air. These made short work of early tanks; the shells they threw would go through armor plate that would stop machine-gun fire or even small cannon shells cold. The Allied forces found this out the hard way; they also found that this gun was marvelously multipurpose, serving the Germans for fortification breaking as well as tankbusting.

The Germans, meanwhile, weren't resting. Although the British developed the tank initially, they came to see it as a cavalry weapon, which was probably unsurprising given the number of cavalry officers worried about losing their jobs over it. They pressed for speedy tanks, able to sweep in and suddenly 'shock' the battlefield, mindful of the history of the cavalry charge. The Germans, however, decided that if their guns could smack around a tank, they damn sure didn't want their own tanks to be vulnerable to such treatment, and went for a range of solutions. At the top of the line came the Tiger tank - a behemoth, with armor that Allied tank guns couldn't penetrate from the front even at point-blank range.

The Allies found themselves in a quandary. The Sherman tank, which wasn't very good, really, was nevertheless the model that the U.S. war-footing economy was tooled up to produce. Retooling would have interrupted the incredible buildup that the U.S. was undergoing, so the design was left essentially the same. Shermans performed fairly badly (even to the point that the Germans called them tommy-cookers since the folks they first saw using them were British, and when hit they brewed right up into a nice bonfire).

For reasons we won't go into here, the Allies won the war, despite having inferior weaponry. Then the fun begins. The Russians had tooled up to produce tanks as well during the war (the T-34 was the mainstay model during this time period) and had managed to turn out an amazing quantity of the things. This, coupled with Stalin's increasing hostility towards the west, ensured that the tank's future looked bright.

Nearly immediately, the Korean Peninsula erupted in conflict. Although Korea's terrain (particularly in the middle and north) is not friendly to tanks, they were rushed into battle. Most of the equipment used in Korea was World War II vintage; not much new stuff trickled in until the end. Afterwards, however, with NATO and the Warsaw Pact staring at each other over Central Europe and the Israelis and Arabic states deciding to get rowdy frequently, the stage was set for constant advances in tank and anti-tank technology. More on this later.

In any case, the tank grew a thicker and thicker skin. So, tanks today are massively armored; in the 1950's, plain steel plate (also known in the biz as RHA, for Rolled-steel Homogenous Armor) became inefficient as it reached thicknesses which made it difficult to machine and of limited utility. Advanced armor began to appear, consisting not only of exotic materials such as ceramic but of complex design, such as spaced armor or even reactive armor. Some type became nearly universal standards, such as Chobham; others were brought into being to defeat a particular weapon system, and didn't outlast the threat they were designed for.

Armor types have cycled as the 'most lethal' antitank weapon type has shifted, from kinetic weapons to shaped charges (HEAT) to spalling attacks (HESH) and back to kinetic and on to self-forging warheads. At the moment, most of the more powerful MBTs (the American M1 Abrams series, the Russian T-84 or T-72, the German Leopard 2, the British Challenger 2, the Japanese Type-90, the Israeli Merkava, etc.) use composite armor, in some cases with reactive armor available as applique kits.

Composite armor is a multimaterial laminate such as Chobham (so named for the UK town where it was first manufactured in deadly secret). Although Chobham is not as effective inch for inch as plain RHA against kinetic weapons, it does much better against the range of potential weapons through its use of different substances such as ceramic layers, spaced layers, and the like (this is supposition; I've never actually seen Chobham in cross-section and if I had probably couldn't talk about it). The ceramic protects against plasma jets from shaped charges; the spaced layers protect against spalling weapons, and the metal layers along with the ceramic against kinetic weapons (the ceramic is dense and the steel dense and hard; it's a mass vs. mass question when a tank is hit by a kinetic penetrator, and at the energies this typically happens the substances involved can act like fluids in terms of their 'hardness').

Active defenses abound as well. Tanks mount smoke dispensers, antiaircraft weapons from light machine guns up to containerized MANPADS missile units (hell on wheels vs. helicopters), ATGMs, reactive armor as mentioned, and of course massive firepower to try to deny any nearby enemies an undisturbed shot. Does it all work? At times, yes, very well. However, tanks are tricky to properly utilize. Most armies tend to discover this fact the hard way, by losing a bunch of them after deploying them improperly.

What's properly? That's a good question that is still being debated on the open plains, steppes and deserts of the world, in arguments punctuated by the loud barks of ultima ratio regum and occasional plumes of fire. Some basics seem to apply, however.

Tanks cannot survive without infantry support if there is even the possibility of enemy infantry nearby. This is because infantry can now carry weapons which, when properly used and with a bit of luck, can destroy tanks. Usually, it's not all that easy to aim (big and heavy for a man) or uses sensors the tank can detect (millimeter wave, laser rangefinder, etc.). As a result, although tanks have fearful firepower, they generally can't use it in all directions at once, and in addition the crew of a tank has notorious limitations on what they can see outside. Therefore, infantry are typically deployed to protect the tank from enemy infantry, and the tank, in reciprocation, protects the retreating or advancing infantry from other tanks and armored vehicles, as well as being handily available to reduce pillboxes and other fortifications.

What are they used for?

Tanks are used for infantry support, for killing other tanks, as a portable artillery reserve in emergencies, for knocking down stuff, and for fortifications, among other tasks. Sometimes they are even used as scouts for their ability to survive contact with the enemy. In infantry support, a tank's job is to provide suppressive fire, to reduce enemy strongpoints, and provide a honking great big piece of armor to hide behind when necessary.

As a portable artillery reserve, they're not too useful, but sometimes you have no choice. The problem is that tank guns are direct fire as opposed to ballistic, so you need to get the tanks in close enough to see what they're shooting at. Given that modern tank guns are lethal out to perhaps 3 or 4 kilometers, though, that may not be a problem.

For knocking down stuff and especially making hash out of enemy fortifications, they're great. Using main gun rounds with HEAT warheads, a tank can knock over pretty much anything that can be constructed by infantry on foot with light tools. If the target is really serious (say, stone) then a kinetic penetrator will shatter it, and a HEAT round will spread the debris. The problem with using tanks in this fashion is that you aren't always sure what's in those fortifications - there might be ATGMs or even large guns that can whack the tank. Commit with care.

The tank excels, though, at killing other tanks, even though it's not always the preferred means of doing so. The U.S. Army would prefer to kill as many opposing tanks as possible with air power, be it fast-mover air support or attack helicopters, and with artillery, before engaging with their own tanks. This makes sense, of course; any edge you have, use!

How do you kill them?

Aha. This is the good part. There's a long history here of smart people on both sides - one set trying to kill the tank, the other trying to keep it alive. There are naturally whole areas of tactics and doctrine that deal with this question, for the best armor is the primary shield - not being in front of the incoming fire. Ideally, you don't ever want to give the opponent a shot at your tank; you'd like to appear behind him when he isn't looking and engage in some exultant up-the-kilt shots.

The methodology for killing tanks differs quite drastically depending on your approach. Approaches are defined as means employed by a particular type of unit, to wit:

  • Infantry: The PBI would very much like anyone except them to deal with enemy tanks. Air cover is good; artillery support using DPICM is better, and a herd of friendly tanks is best of all. However, as is true everywhere, you can't always get what you want, so you make do. For the infantry, the first priority in killing a tank is to immobilize it; a stationary tank can be handled much more easily. Ideally, you'd like to immobilize it somewhere where it will:
    • Block the passage of other enemy vehicles
    • Have constrained fields of view and of fire
    • will be difficult to retrieve
    • will be easy for your forces to bypass
    Again, you can't always get all of these. Sometimes you're lucky just to get one. The fact remains, however,that since a tank's weapons are (for the most part) direct fire, immobilizing it will at the very least allow you freedom of movement in areas you know are not under the tank's surveillance.

    Well and good. But how, Custy old chap, shall we do this?

    The infantry has some great toys available, ranging from the low-tech and massive to the high-tech and tiny, that can cope with tanks. Here are a few perennial favorites.

    • Molotov Cocktail: Not so good at immobilizing the tank, the MC has the twin advantages of being cheap and readily made (Do you drive? Drink beer? Wear a shirt? Great, you've got the three main components of a Molotov right at hand). It is useless against modern tanks with decent environmental and armor systems, however, since the flame can't penetrate. Enough of them on a disabled tank will likely find a vulnerable spot, though, and certainly can make things uncomfortable for the crew.
    • Emplaced Mines: These are cheap and easy as well (requiring not much more than a lot of explosive; the more precise you are, the less required). A well-placed ground or wall mine can be expected (if constructed well) to at least knock a tread off a tank, immobilizing it, if it hits right. If you're very lucky, it may penetrate the armor itself (if you've spiced it with projectiles) and then Bob's your Uncle.

      The problems with mines are quite obvious - they're very, very hard to deploy and detonate properly! Where are you going to put them? How many can you produce to cover an area? I guarantee you that your opponents (the tanks) will do their damndest not to approach the way you think they might, which (if they succeed) will render your mines useless. Still, if there is a natural chokepoint (mountain pass, forest road, bridgehead, etc) then these are your friends.

      Note that mines will only be able to do 'first' damage to a tank; once the tank has stopped, it won't run over any additional mines. If you're concerned about infantry support warning the tanks about your little presents, try scattering a bunch of antipersonnel mines along with them - that'll keep the little crunchy buggers in line.

    • Rocket-Propelled Grenades:RPGs are popular because they're cheap, light for carrying, and can pack a decent punch. The most famous of these is probably the Soviet/Russian RPG-7, which tosses a 80mm grenade for several hundred feet with reasonable accuracy. ICM warheads make this a decent tool; however, it will almost never harm the main armor belt of an MBT. It is extremely useful for knocking off treads, however, and has a chance if it hits the back deck over the engine or the ammunition blowout panels.
    • LAW: The Light Anti-armor weapon is essentially a disposable bazooka, which throws a warhead comparable to an RPG but further and straighter. The American AT-4 is one such example. One non-rocket example is the German-designed Armbrust. These will smack treads, and will (with luck) penetrate the soft(er) spots on a tank, such as armor seams, the rear, and the turret ring. They are also cheap and light enough to be dispensed fairly widely among the infantry 'just in case' and are also handy for reducing light fortifications. They're also hell on wheels against trucks or lightly-armored vehicles such as IFVs and Self-propelled artillery.
    • ATGM: The best option of all, the man-portable ATGM (such as the NATO Javelin or the Russian Sagger) is quite deadly. These range from the smaller, fire-and-forget units like Javelin to the larger, fully guided versions such as TOW, Sagger, Dragon, MILAN and their ilk. Typically, these weapons are employed by a dedicated infantry team, which consists (at a minimum) of a loader/ammo carrier and the gunner/system carrier. These weapons are usually at the top of the line in terms of destructive power; using larger rockets, they can carry much larger HEAT warheads than tank shells can. Newer versions of these weapons are known as 'Top-attack' variants; these will 'pop up' to fly over the target tank the instant before reaching it, and detonate a self-forging warhead or HEAT warhead down at the tank's weaker top armor.

    In general, the infantry's goal is to stop a tank, allowing them to bypass or avoid it, and let a bigger friendly (tank, aircraft, helo) deal with it for good and all.

  • Aircraft: In some ways, this is one of the best means of dealing with tanks because until recently, they've been unable to shoot back. This could be offset by detailing anti-air units to ride along with armor (MANPADS or Avenger-type vehicles for example) and placing large-caliber vertical-capable machine guns on the tanks to shoot at aircraft. Things are improving for the tank, however, as small, containerized MANPADS missiles have begun to appear as applique systems. This allows the tank a relatively decent punch without the need to expose personnel.

    Aircraft can destroy tanks via dropped ordnance (Gravity bombs), fired ordnance (missiles and rockets) or guns. Dropped ordance is best used if your aircraft is designed for high-altitude or high-speed flight; LGB weapons were used enthusistically for tank-plinking in the Gulf War by Coalition forces. The drawbacks are that laser-guided weapons need a designator to illuminate their target; if an aircraft does it, it has to stooge around within range until the bomb hits, and if an infantryman does it, he runs the risk of been discovered. Missiles are good because the aircraft can stand off; Hellfires and AGM-65 Mavericks allow the aircraft to engage from well outside the tank's range. They are, of course, more expensive. Finally, guns - there are only a few guns in existence that have a decent chance of killing a tank which can be mounted on aircraft. The U.S. GAU-8 rotary cannon isn't quite mounted on the A-10 Thunderbolt, the aircraft is more built around the gun. It does work, however; firing 30mm cannon shells with depleted uranium or tungsten noses, it can thresh a tank from the top and be gone before retribution.

    At base, there are two schools of thought on this in the U.S. Military. Due to an accident of history, the U.S. has a deep division between its rotorcraft and fixed-wing combat aviators; the former are Army or Marine Corps, and the latter are Air Force, Navy or Marine Corps. In turn, the two school have different options.

    • Rotorcraft: The U.S. Army Air Force of today (along with its cousins in the Marines) flies armed airplanes that, over the years, have slowly evolved into the airborne equivalent of tanks. The modern Attack Helicopter can be tasked with tankbusting; the U.S. version was designed to do that and little else. Helos rely on agility and speed to avoid return fire from their targets and their friends; since they do move relatively slowly compared to other air targets, they have light armor to allow them to better withstand small-arms fire. Since it isn't feasible to carry aloft a cannon large enough to damage a tank with single shells (especially given the problem aircraft have with recoil) helos rely on ATGMs instead. While attack helicopters typically have all manner of weapons hanging off them, make no mistake; the only ones they'll enter into combat with tanks with are the large guided missiles. Unguided rockets, chain guns, and the like are useful against thin-skinned vehicles and infantry, but big guided weapons like Hellfire are required to play with the behemoths. Tactics...well, we need an Attack Helicopter node for more detail, but typically, attack helos rely on the ambush or surprise strike in order to minimize their exposure to the enemy. Skilled pilots can hide these multiton machines in slight depressions, behind trees, under bridges, and all sorts of places you just wouldn't expect to find an aircraft.
    • Fixed-Wing: There are two types of fixed-wing antitank assets, the slow-movers and fast-movers. The slow-movers, such as the A-10 Thunderbolt in the U.S. and the Su-25 Frogfoot in the old Warsaw Pact, are designed to hit tanks with direct fire weapons and missiles. The GAU-8 cannon of the A-10,mentioned above, can punch through the thinner top armor of tanks from several thousand feet, enough to (hopefully) keep the A-10 out of the range of MANPADS and SAMs. In the event that fails, the A-10 can also drop large gravity bombs. Fast-movers are just that; fighter-bombers that zip across the battlefield and rely on speed and minimal exposure time to keep them safe. The natural tradeoff of this is that hitting the tank is much, much harder; therefore, 'fast-mover' support air forces tend to rely on large dropped weapons that cover areas, such as napalm and dispensing weapons that drop DPICM (like the Panavia Tornado's anti-runway and anti-vehicle dispenser). Their advantage is the ability (theoretically) to hit a large number of targets simultaneously, and to have the aircraft respond at high speed; disadvantages include the lack of accuracy and inability to 'eyeball' verify the target before firing, and the danger of using such loosely-targeted methods when your own ground forces are in close contact. Despite the fact that fast-mover air support is not terribly useful in close armor battles, air forces around the world continue to staunchly maintain that this is not true - after all, you recruit pilots by telling them they'll be knights of the clouds, not turtles of the smog.

  • Artillery and other Indirect Fire: These are also a favorite of infantry, because it means their job involves getting the hell out of the way. Normal artillery (say, 155mm HE shells) aren't very effective against tanks; they rely on splinter damage for most of their killing power, and a tank will shrug off such flinders easily. If the shell hits the tank directly, that is a different story; however, the odds of that are quite low (if you don't believe me, work it out: assume a tank measures 8 meters by 3 meters, and put ten of them inside a square kilometer. Then figure out how many shells you'd need to drop to have even a 50/50 chance of hitting any *one* of those points). Improved artillery, such as DPICM ammunition from MLRS and ATACMS rockets, is helpful; 'smart' weapons ranging from BAT/SADARM to SKEET and JSOW/JDAM are good, too. There was even a brief flirtation with laser-guided artillery rounds, called COPPERHEAD, which was abandoned eventually as being too fragile and too expensive (and needing a designator on the ground).

    Essentially, the ability to kill or disable tanks with artillery is a purely economic one: how many rounds are you willing to expend? Unless you have excellent intelligence and are firing perfect seeking weapons, the number of rounds required to hit anything swiftly becomes enormous as the target's motion and defenses are taken into account. One highly useful ability of artillery is to spread FASCAM - arty-delivered mines - into the target's area. Using this, it is possible to create a mine 'ambush' in a previously 'cleared area.'

  • Other Tanks: Finally. We have discussed above some of the problems inherent in this method; namely, the armor/weapon arms race, the need for proper support of tanks by infantry and aircraft, the high logistical demands of armor, and more. However, not much can really substitute (especially in the mind of the foot soldier) for the comforting bulk of a tank nearby. He doesn't want to get too close, because sure as hell that thing will draw fire; but he doesn't want to stray too far in case he needs to jump behind it to save his skin.

    Tanks kill other tanks by getting either better guns (able to destroy the other tanks at ranges where the other's guns can't hurt you) or by out-maneuvering them, and getting shots in on the flanks and rear of the enemy units.