Why would anyone use tanks anymore in this drone-era? It's like hunting on a turtle.
- A random comment on Facebook
Background
The U.S. Army's main battle tank, the M1 Abrams, currently in version M1A2 SEPv.3 is the heaviest tank in currently service, at 73.6 tons, 12 feet wide, and 8 feet high. The current version costs $24 million each. (An SEPv.4 upgrade has been cancelled by the Army).
The heaviest tank that was ever mass produced beyond a few prototypes was Nazi Germany's 79 short ton Jagdtiger. Only Israel's 65 ton Merkava tank (which is also more advanced, mostly due to its Trophy active protection system) is more heavily armored.
The M1 Abrams has a 120 mm main gun and carries 42 tank rounds (of several types) that have a range of about 2.5 miles. It has advanced sights with night vision features and friend or foe identifiers to prevent friendly fire. It also has a 0.50 caliber machine gun and two 7.62 caliber machine guns, which are now remotely operated. It has a crew of four and is manually reloaded.
Its 504.4 gallon fuel tank gives this tracked vehicle with an impressive ability to handle off road obstacles a range of 265 miles on road, where it has a peak speed of 42 miles per hour, and a range of 93-124 miles off road, where it has a peak speed of 25 miles per hour. It can also ferry itself (very slowly for fairly short distances) across water from an amphibious warship ship or landing craft to shore, or across rivers.
Due to its size, only one can be carried on a C-17 and only two can be carried on a C-5. Mostly, it is deployed by ship and train. But it is too heavy for many European rail bridges, and for many road bridges in much of the world. Its width, weight, and the limited range of motion of its main gun have made it unattractive in old cities with narrow streets and in places with tight mountain passes.
The original version of it, introduced in 1980, was 60 tons and cost $4.3 million each ($10.7 million in 2023 dollars), had a 105mm main gun and carried 55 tank rounds, and had machine guns operated by semi-exposed personnel. It represented a state of the art improvement over its World War II, Korean War, and Vietnam War era predecessors, with its fresh design, in multiple respects, like its powerful 1500 horsepower turbine engine.
About 10,300 of them have been built, both for the U.S. Army and Marine Corps (8,100 delivered), and nine U.S. allies. Currently, it is in service with:
* the U.S. Army (2,640 - 40 M1A1 SA; 1,500 M1A2 SEPv2; 600 M1A2 SEPv3 with another 2000 in the boneyard); the U.S. Marine Corps has transferred its 450 M1s to the U.S. Army,
* Australia (59),
* Egypt (1,130),
* Iraq (101 including one in its Popular Mobilization Force militia),
* Kuwait (218),
* Morocco (222),
* Poland (116),
* Saudi Arabia (575),
* Taiwan (40), and
* Ukraine (12 with another 19 lost in the current war).
Bahrain and Romania have ordered but not yet received them. In addition the Islamic State managed to acquire 9 of them and Hezbollah has 1 of them.
The M1 has also been used as a starting point for several specialized variants including an armored recovery vehicle (basically a tow truck for tanks), a couple versions of land mine clearing vehicles, and a couple of versions of vehicles to deploy assault bridges over trenches and rivers. Other variants such as a bulldozer variant, a battle command post version, an air defense version, and one with an oversized main gun, never made it out of prototype stage.
Beyond the M1 Abrams
A lot has happened in 45 years, and we've learned at lot from using it in combat from the Persian Gulf War to the Ukraine War. So, the U.S. Army has been looking for a replacement and successor to it.
The U.S. Army has already introduced the tank that the Army insists is not a tank, called the M10 Booker Mobile Protected Firepower, a 42-46 ton medium tank with a 105mm main gain, in addition to a 0.50 caliber and a 7.62 caliber machine gun intended for infantry support rather than for use as a full fledged main battle tank, with armor lighter than the M1 Abrams, but heavier than any other armored vehicle in U.S. military service. But this is not a successor to the M1.
The move to replace the M1 has had several false starts over the last decade or two, and one of the most advanced proposals is the Abrams X, which is still in the design phase. This project recently had a major conceptual change to its design, mostly in response to recent developments in armored warfare in Israel and in Ukraine.
The original Abrams X introduced in 2022 already had an autoloader for its main gun, reducing the crew from four to three, and repositioned the crew to keep them further away from the main gun turret which is the tank's most vulnerable point. It also has a lighter 120mm main gun. It also had a 30mm remotely operated cannon (based upon the AH-64 attack helicopter's cannon) in lieu of machine guns. And, it had hybrid power that allowed it to operate in silent mode on battery packs for short periods of time (primarily in a stationary "silent watch" state) and reduced fuel consumption by 50%. And, it would have 360º thermal sights, addressing the limited visibility in the existing M1 Abrams that can allow infantry to sneak up on it and attack it. The total Abrams X weight was supposed to be 60 tons.
AbramsX. Image Credit: Screenshot.
There have also been other changes in the current version:
* The 30mm cannon has advanced smart round that can better penetrate medium weight armor, detonate over trenches that can't be struck directly, and explode in the proximity of drones that aren't directly hit.
* It has the Israeli Merkava tank's Trophy active protection system that detects and intercepts incoming anti-tank rockets, missiles, and suicide drones with a small kinetic energy projectile that detonates them before they hits the tank.
* It has four Switchblade 300 loitering suicide drones, which are remotely operated from the tank, have a range of six miles or fifteen minutes, and "an explosive payload derived from the Javelin missile warhead." This allows it to strike targets previously beyond the 2.5 mile range of its main gun, such as anti-tank missile positions and mortar positions.
Ideally, an Abrams X would also be upgraded to have an ISR spy drone in its unit (or better yet, integrally to the tank itself, with an optional jamming proof fiber optic cord) that could transmit images to it that would warn it of threats that its thermal sensors and sights can't see, a bit like a periscope.
Analysis
The reconceptualized Abrams X is a significant improvement over the M1 Abrams, or the earlier versions of this proposal.
But it still isn't clear that its great weight and size, slow speed because it is tracked, and other inherent problems with the tank concept, justify this upgrade, in lieu of a more fundamental departure from the tank concept, in light of the stunning failure of tanks in the Ukraine War, and other issues with the tank concept that have been revealed in almost every conflict in which the M1 Abrams has been deployed or considered since then.
The U.S. Marine Corps has made the bolder move to abandon tanks entirely.
Even With Improvements Tanks Are Problematic
What problems remain?
1. Any tracked vehicle is much slower on road than a wheeled vehicle. Yet, since the Humvee was introduced in 1985, it has been clear that it is possible to make wheeled vehicles that can go anywhere that a tracked vehicle can go (which was the design requirement for the Humvee). Wheeled vehicles are a bit slower off road than a tracked vehicle, but 45 years of experience in the field has demonstrated that tracked vehicles are actually used off road, when employed in wars, quite infrequently. Tracked vehicles also still struggle in mud. And, tracked vehicles can be more easily disabled by disabling a single track than a 6x6 or 8x8 vehicle can be, since that requires disabling multiple wheels.
2. Tracked vehicles are much less fuel efficient than wheeled vehicles, even when hybrid power (which at least helps). Reduced fuel efficiency need more insecure logistics support, to provide fuel. Fuel tankers generally aren't armored, which is a dire problem in an era when battlefields often no longer have "front lines" behind which unarmored vehicles are safe. Fuel tanks also aren't tracked or equipped for difficult off-road terrain, which means that the entire unit including its logistics support can't cross terrain that only tracked vehicles can cross. (An alternative to deal with the fuel logistics problem would be to look into so called "nuclear batteries", which are powered with radioactive decay of non-uranium, non-plutonium isotopes like thorium.)
3. Slow speed means that a unit with tracked vehicles have to be transported long distances by ship or rail or a flatbed transport, unless absolutely necessary. And, again, those tracked vehicle transports are unarmored and vulnerable, in an era where battlefields don't have safe spaces behind the front lines, and the transports can't go to all of the places that the tracked vehicles themselves can go. It is also much easier to disrupt a rail line or a port big enough to off load tracked vehicles than to disrupt a road in a way that an armored vehicle can't easily go around. This limitation isn't a big concern is you are a geographically small country like Israel or Taiwan or Kuwait planning to employer your tanks domestically against foreign invaders or insurgents. But it is a huge issue for a country like the United States which would almost always be fighting wars in which tanks might be used on an expeditionary basis.
4. Slow speeds mean that in a "fight or flight" situation, the tank can't flee. It has to fight, which is a huge problem if your opposition has greater range anti-tank weapons than the range of your offensive weapons. Conversely, faster opponents with wheeled vehicles can quickly flee from you to beyond the range of your main gun or direct fire cannon, if they are near the edge of your range when they notice your tank. Carrying armed drones helps, but isn't a perfect solution. Any military should be embarrassed to have major offensive systems that can be outrun by a Smart car or a trail motorcycle.
5. Wide vehicles like the M1 Abrams and Abrams X still struggle in the narrow streets of historic cities and villages, on narrow mountain passes, and on narrow roads in dense forests and jungles. Creating barriers that narrower civilian vehicles and narrower military vehicles can pass through, but a wide tank can't, is fairly easy to do if you are preparing to defend against a tank assault.
6. Even at 60 tons, the Abrams X is still very heavy. You can still only transport one in a C-17, or two in a C-5 that requires a more improved airfield. This is still too heavy for most bridges over canyons and rivers in most of the world that are designed to only handle traffic as heavy as commercial tractor-trailers and their loads. This is still too heavy for trains transporting them to the theater of battle to carry them over rail bridges in much of the world. This still limits how many of them can be carried on a landing craft from an amphibious ship. For example, a U.S. Marine Corps Landing Craft Air Cushioned (LCAC), which entered service in 1986, can carry only 60 tons at regular weight and only up to 75 tons if deliberately overloaded in a way that degrades their performance. Just ordinarily driving one over ordinary civilian roads will often damage the road if it isn't built up to the most modern and robust standards, harming good will with the local population. Delivering tanks to an emerging conflict by ship, rail, and flat bed truck, rather than medium or heavy airlift, can take many weeks by which time the armor may be too little, too late. And, medium or heavy airlift capacity is scarce and still requires at least a fairly decent sized improvised air field.
7. Its great weight also makes it easy to make traps for them by basically building a covered basement or trench that other vehicles can drive over, but that would collapse under a tank's weight, leaving it in a pit. Driving such a heavy tank into the first floor of a building with lower floors presents the same problem.
8. The Abrams X, like the M1 Abrams and the vast majority of other modern tanks, can only aim their main guns so many degrees up or down. This means that the main guns can't be used against adversaries on high ground such as the higher stories of a tall building in urban combat, or the top of a canyon when the tank is driving on a road through the bottom of the canyon (which is a common road design in places where have canyons). It also limits the use of the main gun against drones, helicopters, and close air support aircraft, in an improved anti-air role. The armed drones of the Abrams X and its 30 mm cannon help deal with this, but are an imperfect solution. The 53 ton Russian Terminator armored vehicle was designed to address the heavy losses that Russian tanks took from these kinds of tactics fighting insurgents in the Caucuses:
This vehicle was designed for supporting tanks and other AFVs in urban areas. The BMPT is unofficially named the "Terminator" by the manufacturers. It is heavily armed and armored to survive in urban combat. The AFV is armed with four 9M120 Ataka missile launchers, two 30 mm 2A42 autocannons, two AG-17D grenade launchers, and one coaxial 7.62 mm PKTM machine gun. The BMPT is built on the chassis of the widely used T-72 main battle tank. . . .
Combat experience during the lengthy war [with Russia in Afghanistan] revealed that infantry fighting vehicles (IFVs) like the BMP-1 and BMP-2 cannot fully deal with infantry, despite the BMP-2's high gun elevation. Although main battle tanks (MBTs) possessed a high amount of firepower, the limited elevation and depression angles of the main gun made them easy targets in mountainous and urban terrain. It was evident that a new vehicle concept was needed. . . . The main requirements for this new machine were to possess large firepower, high angles of elevation and depression, and protection equivalent to that of an MBT. An additional requirement that was meant to supplement the latter was enhanced protection from close-range hand-held RPGs.
The need for such a vehicle became even more evident during the First Chechen War. When using conventional armor during urban engagements, Russian forces suffered heavy losses in manpower and equipment, including the destruction of an entire mechanized brigade during the First Battle of Grozny. While these losses cannot be entirely blamed on technology, it became clear that a dedicated anti-personnel fighting vehicle would provide valuable assistance in an urban environment. Self-propelled anti-aircraft guns were used as a temporary solution in Chechnya. However, these vehicles were not well-armored and did not possess the obstacle-clearing capabilities of an MBT.
9. The main gun of a tank, conceptually, is primarily for accurately striking other tanks at relatively close range. In practice, however, less than 5% of tanks are destroyed by other tanks in modern warfare. These days, a tank's main gun is basically a solution looking for a problem. Tactically, tanks are no longer the main kind of anti-tank weapon, several other options are higher up the list including anti-tank missiles and rockets (from dismounted infantry, Humvees, helicopters, drones, or close air support aircraft), close air support cannons, anti-tank mines and IEDs, and artillery. Anti-tank missiles are just as good at destroying an enemy tank, have longer range, and even with their launching systems are much lighter than a tank's main gun and shell. Anti-tank missiles cost more than a tank shell, and one would typically carry fewer of them than the 42 shells that an M1 Abrams does, but given the pretty modest number of tank on tank engagements, the cost difference isn't huge and is balanced by not having to spend immense amounts of money on a heavy armored vehicle to carry the main gun.
10. The main gun of a tank has also been justified as a way to penetrate fortifications like bunkers in support of infantry. But, bunker busting recoilless rifles (i.e. bazookas), or anti-tank missiles used against a bunker, are likewise much less heavy than a tank's main gun and are comparably effective against all but the heaviest bunkers, which can be dealt with using heavier missiles and bombs, delivered by helicopters, drones, aircraft, or just long range cruise missiles launched from land batteries or naval ships. There isn't a great demonstrated need for bunker busting that a 120mm main gun can address, but an 84mm recoilless rifle, or suicide drone, cannot, in actual combat situations. A 120mm tank round can bust through 8-12 inches of reinforced concrete (see also here) with three tank shells, a 105mm tank round can probably penetrate a little bit less. A 30 mm cannon round can break through four inches of steel (and concrete and steel are roughly comparable in the difficulty of penetrating them). An 84mm recoilless rifle can penetrate up to 16 inches of armor or concrete at ranges of 500 yards or more, but requires far less weight and bulk and the main gun of a tank, and the full 2.5 mile range of a tank's main gun is rarely necessary for bunker busting.
11. The M1 Abrams, the Abrams X, and almost all other modern tanks lack any kind of air defense capability, although the Abrams X will at least have Trophy active self-defenses which can intercept income shells and suicide drones. This means that they have to rely mostly on other air defense capabilities in their unit to respond to helicopters, close air support aircraft, and drones. Relying on dismounted infantry with MANPADs or specialized anti-aircraft vehicles in the unit is a workable response to attacks from a small number of armed helicopters, close air support aircraft, or large drones pretending to be helicopters or CAS aircraft. But, it is a less workable solution to attacks by large swarms of small armed drones and suicide drones.
12. It isn't clear that either the M1 Abrams or the Abrams X have the v-shaped hulls that help minimize damage from anti-tank land mines and IEDs, unlike most modern armored wheeled vehicles.
Filling The Tank Gap
There is a place for some level of armor protection in modern warfare. Armor much less robust than an M1 Abrams tank is entirely adequate to make a vehicle and its occupants almost completely impervious to small arms fire up to about 0.50 caliber (12.7 mm) rounds and indirect hits from shrapnel (including the remnants in income shells defeated by active defense systems like Trophy). It might even make sense in some "high end" applications to seek armor that can defend against 20mm-40mm cannon rounds and grenades.
Likewise, MRAPs were found to be desirable, because some form a mine resistance, at least against basic IEDs, is necessary even in "low end" counterinsurgency conflicts.
The Iraq War clearly demonstrated the problem with using unarmored, flat bottomed Humvees in places where its occupants were likely to be exposed to small arms fire and IEDs from insurgents.
But it has also been clear continuously from the Gulf War, and even more emphatically in the Ukraine War, that no amount of passive armor on a tank can protect it from anti-tank missiles, or direct hit from an anti-tank shell from another tank, or a direct hit from an artillery round or a drone delivering one (although the armor can increase that odds that the crew survives while the tank is lost).
The weight to offensive power ratio heavily favors weapons like the Javelin anti-tank missile and the 84mm recoilless rifle over a main tank gun for tasks like destroying armored vehicles and busting bunkers. These need to replace the main guns of tanks.
Armor has its place, but only to a point. If an adversary has military grade anti-tank weapons and/or air power from close air support aircraft, guided bombs, armed helicopters, or armed drones, tanks are highly vulnerable targets at a severe disadvantage.
Not every adversary has those capabilities, and when the adversary does not, armored vehicles have a place. But armor beyond what is necessary to defeat small arms and shrapnel is mostly a waste, and attempting to have enough armor to defeat a direct hit from a tank shell or artillery shell is futile.
Likewise, there is virtually no situation where tracks rather than wheels make sense for military vehicles, and even if there is, it is a very niche situation best dealt with using a small number of specialized vehicles made this for particular purpose, and spread across every kind of vehicle in a given military unit since the less capable vehicle in the unit governs what the unit can do.
At some point, lasers might address the air defense, drone defense, and active defense shortcomings of tanks, and we're close to that point, but it isn't clear that we are there quite yet.
It is possible to use weapons lighter than a main tank gun, armor only sufficient for the circumstances where it can't be defeated anyway, and wheels (basically with moderately armored wheeled missile tanks), to greatly reduce the weight (and size) of ground combat vehicles used instead of tanks, and the logistics of deploying them and then fueling them in the field makes reducing weight highly desirable.
The Sweet Spots For Weight and Size
Making armored vehicles less wide than the 12 feet of an Abrams tank, probably down to the 8.5 feet of a semi-truck makes sense, because that is what roads, bridges, and tunnels all over the world are designed to manage, for missions like urban warfare and deployment in mountainous and heavily forested areas.
There are basically some sweet spots with regard to weight for military planners.
Vehicles 19 tons or less, like the Stryker and the HIMARs system (and historically the 17 ton M551 Sheridan light tank), can be delivered by a C-130 (and if its is even lighter, by military heavy lift helicopters, Ospreys, or future transport drones), with four of them per C-17 airlift load, eight per C-5 airlift load, and two on an intermediate size European airlift transport. This is also approximately the weight of a standard tractor-trailer or shipping container with its load.
At 15 tons or less, like the 11 ton joint light tactical vehicle (JLTV), you can carry five in a C-17 airlift load and ten in a C-5 airlift load. The heaviest airlift possible for a heavy lift helicopter is 16 tons for the heaviest lift helicopters (a CH-53 Stallion), 8 tons for the next heaviest lift helicopter (a CH-47 Chinook), and 10 tons for an Osprey tilt rotor aircraft.
For systems of 20-25 tons, you can't use a C-130 or helicopter, but can fit carry three in a C-17 or six in a C-5, or one on an intermediate size European airlift transport.
Two vehicles more than 25 tons but 38 tons or less (like the Bradley infantry fighting vehicle) can be delivered per C-17 airlift load or LCAC load (and four of them can be delivered per C-5 airlift load), and one of them can be delivered some intermediate sized European Airbus made airlift aircraft, which are between a C-130 and C-17 in size.
Getting even the heaviest military vehicles at least down to 38 tons each, and getting many military vehicles lighter than that, if at all possible, is imperative to an expeditionary military force like that of the United States. Historical and present examples of military vehicles in this size class are recapped in this post.
A Footnote On Howitzers and Mobile Mortar Systems
While traditional howitzers (cannon artillery) were important in the early days of the Ukraine War and are still receiving fairly heavy use there, it still makes sense to replace them with guided missiles and drones.
Their range is quite limited (rarely more than 24 miles without basically guided missile rounds). Their accuracy is poor (which undermines the benefits of the low cost of artillery shells relative to missiles, and isn't that cost competitive with the FPV suicide drones used in Ukraine). And, the artillery launchers are expensive, heavy and slow. Howitzers have been destroyed at rates comparable to tanks in the Ukraine war.
Artillery missiles and suicide drones just make more sense.
Mobile mortar systems make even less sense, even though they are much more sophisticated than they used to be. They back less of a punch, they can't be used too close the way that direct fire main tank guns can, and their range and accuracy is much more poor than that of conventional howitzers let alone missiles or drones. Yet, these systems are expensive and heavy relative to the firepower that they deliver. There are small niches where they can be competitive with traditional canon artillery, and mortar shells can be cheap, but they aren't competitive with suicide drones in cost or weight.
Perhaps small infantry mortars have a limited place as a simple and light stopgap, but otherwise, a full transition makes more sense if you are starting from scratch.
The DARPA NOMARS program has successfully launched the USX-1 Defiant, a 180’, 240-metric ton medium unmanned surface vessel designed to revolutionize autonomous operations at sea. DARPA Photo 
