Resurrection of the Turretless Tank.
Resurrection of the Turretless Tank
A topic that I have been reluctant to cover on the Scrapboard has been that of tank destroyers.
The main problems are one of mentality rather than tactical worth.
In the 1930s and 40s, the US Army formed a doctrine as to how armoured forces might be used against it.
Their conclusion was that there was a requirement for highly mobile anti-tank forces.
A number of wheeled (M6, T55E1), half-tracked (M3, T48) and tracked (M10, M18, M36) Gun Motor Carriages (GMC) were accordingly created. All of these vehicles were lightly armoured and capable of relatively high speeds.
Unfortunately, the American tank destroyer doctrine was flawed.
The German Army actually operated in combined arms formations that the specialized Tank Destroyer (TD) battalions were ill-suited to counter.
Another problem was the tank-like appearance of the tracked GMCs.
As far as some commanders were concerned, anything that looked that much like a tank was a tank and was to be used as a tank.
Lightly-protected GMCs were often used in roles for which they were not suited and criticized for not being able to perform duties they had not been designed for.
As a consequence, it has been ingrained in some American military psyche that tank destroyers don't work.
Despite this, the Stryker Mobile Gun System (MGS) replicates the flaws of the American tank destroyer GMCs.
In other armies, properly used tank destroyers were very successful.
The tank destroyer is essentially an anti-tank gun that can move itself.
Many of the earliest tank destroyers were anti-tank guns mounted on any available vehicle chassis.
As the war progressed, dedicated designs were produced. Often the design took the form of a well-armoured turretless tracked vehicle.
German variants took the name panzerjäger or jadgpanzer. While this is more accurately translated as tank-hunter or hunting-tank I am going to continue to observe the convention of calling gun-armed anti-tank vehicles destroyers and missile-armed vehicles hunters.
The British Archer vehicle is notable in that as a mobile anti-tank gun, the designers chose to place the gun to fire to the rear of the vehicle, over the engine deck. The drivers position faced away from the action, allowing the vehicle to rapidly retreat and relocate.
The same concept was used in the Swedish S-tank, which was effectively a tank destroyer. The S-tank crew consisted of a commander, a driver-gunner and a rear-facing driver/radio operator.
The story of German tank destroyers is intertwined with that of the assault gun.
During the First World War German soldiers dragged or pushed infantry guns across no-mans land to provide support fire to infantry.
Logically, for the next war, a vehicle that could fill the same role was created.
These assault guns were well-armoured, turretless vehicles.
The earliest versions used short-barrelled, low-velocity guns. It was not long before 75mm anti-tank guns were mounted instead, giving the assault gun an anti-tank capability.
In German use, assault guns were crewed by artillerymen, while tank destroyers were operated by panzerjaeger.
Assault guns were often used in a defensive, anti-tank role. Tank destroyers were often used in an offensive, infantry-support role. Both types were sometimes used as tanks. Being relatively well-armoured, the German assault guns and tank destroyers fared better in the tank role than their American equivalents.
Assault guns and tank destroyers formed a significant portion of Germany’s armoured forces. The Stg III alone was Nazi Germany’s most produced full-track armoured vehicle and second-most produced armoured combat vehicle of any type after the Sd.Kfz. 251 half-track.
If the war had continued, it seems likely that single designs such as the E-25 would have served in both the assault gun and jadgpanzer roles.
The use of turretless assault guns and tank destroyers declined in the latter half of the 20th century.
The multi-role Main Battle Tank (MBT) has become the direct-fire platform of choice.
The ASU-85 is still apparently used by Vietnam, an interest in upgrading them having been expressed in 2016. SU-100s have been reported used in combat in Yemen as late as 2015.
The other day I was reminded of some comments by Richard Simpkin in his book Race to the Swift. Writing during the Cold War, he notes on p.62:
In developed countries, most of all perhaps in developing ones, there is a tremendous military advantage in keeping within the width of the largest commercial and agricultural vehicles. Gross vehicle mass (MLC) of routes is also important here, both directly and because especially in tracked vehicles, width marches with it.
On p.80 Simpkin notes that the West German road system had only one east-west route of MLC 50 or higher capable of taking tanks that was available to each NATO division.
Simpkin suggests that combat vehicles be designed within a top limit of 38 tonnes (Just over MLC 40). Vehicle width probably has a little more design leeway. Commercial width is 2.75 metres in many European nations, which is the same as that of an Alvis Stormer AFV, and more than that of a M113.
Incidentally, the 30-ton Argentinian TAM tank was designed to be compatible with that nations infrastructure including its roads, rail systems and bridges.
Designing effective AFVs within the parameters that Simpkin defines proposes some interesting challenges.
A VLS missile-armed tank such as the Thunderback that I have proposed elsewhere could be built within these parameters.
So too would the Threat Suppression Vehicle I have suggested.
If we want big guns, either as artillery or for direct-fire, compromises may need to be made.
For artillery SPH and SPGs we may have to omit features such as fully-enclosed crew positions or fully traversable turrets. Most-truck based artillery systems already do without these. These same systems could be made much more capable if mounted on a flatbed tracked platform as I describe for the UTA.
For a large-calibre direct-fire platform, a less conventional approach may need to be considered if mass is to be reduced.
A variant of the CV90 with a 120mm tank gun has been demonstrated. Weight is around 30 tons. The Chinese type 89 tank destroyer has a turret-mounted 120mm gun and is of similar weight to the CV90120. I suspect that the armour protection of both vehicles is relatively modest.
Potentially, we could create a tracked vehicle that mounts a 120mm tank gun but does not have a turret.
This would produce a considerable weight and cost saving, a saving that could be used to increase protection from armour and other systems.
BAE have published some concept artwork of a vehicle they call Charger, which is apparently turretless and has the crew positioned in the rear.
They propose that this vehicle would be 30 tons.
Press releases are vague as to whether the armament illustrated is a gun or a gun-mortar.
The dozer blade is an intelligent feature, given how useful the Israelis have found their D9s, although the form shown in the illustration limits main weapon depression, vital if fighting from higher ground.
Fitting the vehicle with anything less than a 120mm gun is likely to have its anti-tank capability criticised.
The rifled L30 120mm is the more versatile system, but there will doubtless be considerable pressure to use a smooth-bored weapon for its anti-tank performance and to standardize.
The XM1069 AMP round may increase the capabilities of the smooth-bore 120mm without the need to carry multiple ammunition types.
The vehicle should be designed to accommodate either type of 120mm weapon, and have potential to be upgraded to the 130mm or possibly even the 140mm tank gun if these weapons ever become necessary.
It would be useful if the weapon can also provide high-angle fire so that it can engage targets from behind cover but this may not be practical.
To minimise length, this proposed reincarnation of the turretless tank destroyer/assault gun would have a front-mounted engine and a rearward fighting compartment. The barrel therefore projects over the engine deck in the manner of the Archer or Elefant/Ferdinand.
The Swedish S-tank (“despite the name, a tank destroyer”) had a fixed gun. Traverse was by slewing the vehicle, elevation and depression by adjusting the suspension. Most assault guns and tank destroyers have had gun mounts with some degree of independent traverse, elevation and depression.
The main weapon would have a measure of independent traverse, which may use a barbette-type mounting.
An externally mounted main gun with provision for limited traverse may also be practical.
It is possible that the gun system may be mounted on a pedestal that places the weight directly on the vehicles floor.
Without the mass of a turret or armoured superstructure to move, weapon traverse can be more responsive.
The omission of a turret may also simplify the design of an auto-loading system.
My original preference would be to have a human loader in addition to the auto-loading system. This crewman supervises the loading mechanism and also helps man defensive systems. Space and manpower limitations will probably prevent this. One of the advantages of a modern tank destroyer is that it only needs a crew of two.
New technologies will also be applied. The gunner and commander may have override controls to slew the vehicle to bring the gun to bear. A rear-looking video system will allow the driver to move in either direction with equal faculty. With modern technologies each crew station can handle any role, allowing the vehicle to move and fight despite injuries or damage. Duplicate control systems mean that a separate driver is redundant. Either crewman may serve as gunner or driver, or man the surveillance systems. Virtual transparent armour will increase situational awareness.
Tactics for using turretless gun systems will need to be developed or relearnedThe limited traverse of the main weapon will doubtless concern some modern tankers.
It is worth bearing in mind that modern tank turrets have become so massive that tracking fast-moving targets can be problematic anyway.
The Nazis and Soviets both used turretless gun systems in close terrain such as urban environments. It has been done before and we can rediscover how.
The solution is probably to think beyond the individual vehicle and ensure that it operates with adequate dismounted infantry support.
It should, however, be kept in mind that the tank destroyer is a specialist and not ideal for combat in close country nor offensive actions.
I suggest that the vehicle mount at least two remote weapon stations (RWS), preferably of .50 calibre. These will be positioned so that they can cover the vehicles rear and flank quadrants, rather like the wing guns on an ACAV. This would make the vehicle better equipped to handle swarm attacks from multiple directions than most conventional modern tanks.
Another solution may be for the 120mm-armed vehicle to work alongside turreted Thunderbacks, TSVs and IFVs.
To conserve main gun ammunition, it may be prudent to include a secondary weapon such as the 30mm M230.
An under-armour 60mm mortar might also be considered.
A number of guided rounds are being developed for the 120mm gun. It may, however, be more prudent to provide the vehicle with a small number of VLS tubes that provide a number of larger-calibre guided projectiles.
This may be “gilding the lily”, however.
The primary role of a tank destroyer is as a defensive, long-range weapons system. To be effective on a modern battlefield it will need to work with other fighting vehicles and infantry, and these may be better suited to handling local defence and guided missile roles.
Since I originally wrote this article I have been fortunate to acquire and read copies of Richard Simpkin’s “Tank Warfare” and “Mechanized Infantry”.
The former book in particular makes a convincing case for an improved S-tank-type tank destroyer with a 120mm smoothbore gun to be deployed for the defence of Western Europe against Soviet or Russian aggression.
Massing around 40 tonnes, the tank destroyers would have greater operational mobility than traditional MBTs. In other words, they have a better chance of reaching an incursion soon enough to contain it. If necessary, these vehicles are light enough to use floatation screens to cross river obstacles.
A high power-to-weight ratio gives the vehicles a good road speed.
A 25% reduction in vehicle mass yields a 62% saving in logistic and engineering requirements.
Only needing a two-man crew, more vehicles may be crewed and fielded. Without a turret and the associated machinery the tank destroyers are simpler and cheaper to manufacture.
A small turret, slaved to the controls of either crew member, mounts a 20 to 30mm cannon.
Ammunition for the main gun is held at the rear of the vehicle. Magazines of rounds slide in for easy replenishment. These magazines can be ejected in the event of fire.
Being low-slung, small volume and with very sloped armour. these vehicles are well protected, yet have firepower equal or better than heavier MBTs.
The tank destroyers would be supported by a family of vehicles of similar weight based on the same hull. At platoon level these would include infantry carriers and turreted tanks with a lighter gun for local defence. At company level, a variant would serve as air-defence platforms.
Large numbers of such tank-destroyers would prove useful to nations such as South Korea.