60 cm Morser L / 8.45 cal. 600 mm or 54 cm Morser L / 13 cal. 540 mm and its improved version 60-cm Karl Gerat 041 is the heaviest self-propelled siege mortar used during World War II. It was part of the armament of the German army. Work on this powerful weapon began at the Rheinmetall concern in 1936, and the first example of this weapon entered service with the Wehrmacht in 1940. During the entire war, one prototype was created and six copies were used by the army with proper names: Baldur, Wotan, Thor, Odin, Loki and Ziu. Karl mortars were used in a marginal way during World War II. They took part in the siege of Sevastopol in 1942 and in the suppression of the Warsaw Uprising in 1944. This type of mortar was an extremely bulky weapon. It was characterized by very low mobility, the transport of ammunition was also a problem, for which a specially converted version of the PzKpfw IV was used. Loading took a long time, and before firing, the Karl-type mortar had to land on the ground to relieve the suspension. The whole structure weighed about 124 tons, the range with a 60 cm missile was only 6800 m, and with a 54 cm missile it reached 10,400 m. The mass of the missile was 2.17 t for the 600 mm caliber and 1.25 t for the 540 mm caliber. Given these data, it is easy to conclude that a 5-6 Ju-87 raid would have had similar effects to firing a Karl-type mortar.
Munitionsschlepper Pz.Kpfw. IV is a German tracked ammunition truck from the Second World War. The first prototypes of the car were built in 1939, but small-series production probably started in 1941. It is assumed that the length of the car was 5.92 meters, with a width of 2.98 meters. The weight of the car was probably about 24.5 tons. The vehicle did not have any permanent weapons. Munitionsschlepper Pz.Kpfw. IV was developed as a highly specialized ammunition vehicle designed for servicing Karl Gerät 040/041 self-propelled mortars. Its design was based on the Pz.Kpfw. IV Ausf. D and F1. Compared to its prototype, the presented car had a redesigned front part of the fuselage and the turret with the main armament was removed from it. On the other hand, in the rear part of the car, on the engine compartment, there was a container in which 3 to 4 600 mm rounds were transported for the Karl mortar. The vehicle was also equipped with a special crane designed to carry these cartridges. It can be assumed that a total of about 15 vehicles of this type were built, including prototypes.