While proven to be much of a liability instead of a tactically useful asset, there is no denying that there existed a superheavy tank craze even during the WWII era, as displayed by each warring state attempting to develop their own version of such a humongous vehicle. Maus (188t), O-I (150t), FCM F1 (139t), KV-5 (100t), TOG II* (81t) were easily among the list of well-known superheavy tank designs throughout the war, some never even left the drawing board. The Canadians at one point were also considering building a superheavy tank with 4 inch naval gun turrets (courtesy of Whelmy). Speak for the obsession of gigantism.
Now, before you come over to piss me off that I missed out the T28/T95 from the US side, I did in fact recognize the 86-tonne bonker that has just recently been preserved and is now residing inside NACM’s tank house comfortably. But did you know that the T28/T95 wasn’t the only superheavy tank project that the US had come up with? Most people will most likely be familiar with the T28/T95 as the US’s sole superheavy tank project in their entire history, but are not aware of another type of superheavy tank thought up by the Army Ground Forces (AGF) during the last phase of WWII.
The U.S. Army Ground Forces’ 150-ton Superheavy Tank.
Under the context of “research purposes”, the Army Ground Forces Equipment Review Board was initiated on 2 January 1945, with the goal of reviewing the armament and equipment requirements for the Army in the future. One of the subjects discussed in the subsequent report, dated 20 June 1945, was the feasibility of developing superheavy tanks, after a chain of events that led them into learning about the existence of German superheavy tank projects sometimes in early 1945, particularly the Maus and E-100.
Well, AGF being AGF, they proposed a tank design with a MINIMUM weight of 150 tons (136 metric tons), as well as relatively conventional ones such as a fully traversible 360° power-driven turret and a HV gun of at least 105 mm in diameter. Whoop dee doo, the armament recommendation went wild shortly on the paper by the use of azimuth and elevation stabilizers for that caliber of a gun, and supported with a dual feed autoloader to allow cycling through multiple ammo types. As far as armor was concerned, the description was plain and simple: “The thickness of the armor was to be the maximum possible, consistent with the weight of the tank”. The 86-ton T28/T95 was already capable of projecting over 12 inch (305 mm) of frontal armor, now go figure a tank 1.5x its weight. There was insufficient information in regards to its mobility, although an artist’s concept was included in the board report, depicting what appeared to be a gargantuan tank in a semi-trailer type hull configuration, and armed with a 155 mm M2 L/45 artillery cannon with a giant muzzle brake. It wasn’t even a cut down 155 mm T7 L/40 like that in the T30 Heavy Tank, but a full blown Long Tom in a fully enclosed turret. Kind of understandable why they wanted an autoloader for this type of vehicle regardless of the weapon configuration.
Looking at the vehicle layout further, we can identify some semblance to the contemporary US tanks of WWII. It had the front (the “tractor”) of a heavily modified, on steroids, cast M4 hull, with conveniently large cupolas for both the driver and bow gunner. On the back (the “trailer”), it had the turret derived from multiple tanks, ranging from an M4(75)’s low bustle turret rear, M26’s gun mount, and a extensively rearranged T29’s turret roof, especially with the appearance of two standard type escape hatches for loaders. A mini turret was attached to the mounting point between the tractor and the trailer, most likely armed with dual M2HB .50 cal machine guns, almost exactly resembling the T121 TC cupola by shape and purpose. This begs a question on whether the bow gunner also had the .50 cal too and not the .30 cal, since the dimension looked similar, and would be a massive disappointment to its size if it wasn’t. Back to the aft section, it slightly resembled a shorter T95 hull with a space for two engines / one really big engine, at least. Both platforms used torsion bar suspension, with the tractor having a pair of tracks, and the trailer having two pairs of tracks. Again, nothing was known about what type of transmission or engine it would be powered with, not even an accurate estimation could help.
Aside of the AGF 150-ton superheavy tank, other tank designs were also pitched, including a 25-ton light tank as a replacement to the M24, and armed with a 76 mm for self-defense against enemy tanks. The other was a standard 45-ton medium tank armed with a extremely high velocity 76 mm gun capable of penetrating 203 mm of armor angled at 30° from 914 meters. And the last would be a 75-ton heavy tank protected with at least 267 mm of armor at 0° with a top speed of over 30 km/h. The AGF projects were, in retrospective, similar to the German Wa Prüf 6 projects made to develop new panzers based on weight for each separate class, including light, medium, heavy and superheavy tanks.
With a remarkably radical design for a superheavy tank utilizing the semi-trailer hull, an immediate solution was required to facilitate its transportation overseas, which might have been its biggest design challenge instead. Superheavies in Europe didn’t get to experience the same blunder that was the intercontinental tank transportation as the US did during the entirety of WWII. However, the AGF superheavy tank project was never carried out considering it was just a research study to determine the value of an arguably archaic and outdated class of tank.
R.P. Hunnicutt – Firepower: A History of the American Heavy Tank
R.P. Hunnicutt – Patton: A History of the American Main Battle Tank