Weapons of World War Two
60 cm mortar Thor
In 1935, the Wehrmacht, in full phase or rearmament, requested from the German heavy industry weapons of uncommon characteristics. The famous supercannon "Dora" actually could not be considered related to the war material of normal utilization. It would be easy to intuit that it was not an ordinary cannon, but one which had been projected to fire against a very specific target: the Maginot Line. A weapon made on purpose for a very particular necessity. The same year it was ordered a gigantic piece of siege artillery: a 600-millimeter mobile mortar, capable of moving by its own means to take positions against the targets that, because of their distance from the railway lines, could not be reached by cannons installed on railway carriages.
If we consider the taste that Germans had always shown for this type of artillery, and if we think that in 1935 mobile artillery, in the true sense of the word, still had not been born, this unexpected requirement from the Wehrmacht of a weapon of this genre seems, at least, strange. However, if we looked to a railway map of the Europe of that time, we would see that the borders of the western nations and the very French coast of the Channel, the wide natural frontier of England, are crossed lengthwise and crosswise by railway lines. To the east, however, things were different: the Russian railways, for example, were few, bad and, almost all, with a width different from the European one; hence useless for an eventual military utilization. Russia possessed, besides, a good fortified line and many strongholds which were, on the largest part, beyond the range of the railway artillery.
Hence Germany would possess artillery of large caliber that would not require of those communication lines for its operation. In the early 1939 the company Rheinmetall-Borsig was able to present the prototype of a steel mastodon, which weighed 123 tonnes, denominated "Karl", on which immediately were effectuated the trials and ballistic tests. Barely two years later, in 1941, were already finished the first two series weapons, denominated "Thor" and "Eva". These were gigantic mortars, capable of shooting both piercing or high-explosive projectiles, of truly devastating effects, both because of their own weight and the steep angle, characteristic of mortars, with which they fell.
However it was thought that its range was not satisfactory and it was studied the installation of a cannon of lesser caliber (540 millimeters), but with external dimensions matching those of the 600-millimeter cannon, so both could be installed in position without requiring further modifications. The lesser caliber, like the length of the cannon, allowed to considerably improve the range. Besides several of these cannons, were built four tracked tractors. The engine, a Mercedes-Benz, could be installed in both Diesel and gasoline versions but, generally, the first type was preferred.
Before opening fire, a gear system allowed to block the suspension and descend the body of the carriage, to make it rest directly on the ground. This prevented the recoil from damaging the transmission mechanisms. For short displacements, the "Thor" used its own engine, while for longer travels the tractor was loaded in a special towing and the cannon in another one. Both were then towed by artillery tractors. For very long travels it was used, however, the railway transportation. The "Thor" could be loaded, by means of a special clutch, in two platform wagons.
Weight: 115 tonnes (540 millimeters); 123 tonnes (600 millimeters)
Length: 11.15 meters
Width: 3.16 meters
Height: 4.78 meters
Armor: 12 millimeters
Engine: Mercedes-Benz Diesel of 12 cylinders in V and 580 horsepower
Maximum speed: 10 kilometers/hour
Weight of piercing projectile: 1.5 tonnes (540 millimeters); 2.16 tonnes (600 millimeters)
Weight of firing charge: 180 kilograms (540 millimeters); 240 kilograms (600 millimeters)
Range: 10 kilometers (540 millimeters); 4.5 kilometers (600 millimeters)
Also in Weapons of World War Two: