@CWO:
@KurtGodel7:
Germany had been developing the Landkreuzer P.1500 Monster tank. As the name indicates, this tank weighed 1500 tons. That’s 50 times the weight of a Sherman! The P.1500 Monster fired 800mm shells; with each shell weighing about 25% as much as a Sherman. It would have also featured two 150mm secondary guns. These secondary guns were larger than the primary guns of almost any other WWII era tank.
The P.1500 was intended to be powered with four diesel engines–the same kind of diesels used to power U-boats. Because this tank would have been too heavy to cross bridges, it would have driven along the riverbed bottom; while using a snorkel to provide air to its engine. The Monster would have had a crew of over 100.
The P.1500 concept essentially involved arming a tank with an 800mm gun similar to the Schwerer Gustav and Dora 800mm railway guns, which I believe were the largest-caliber artillery pieces ever used in combat. Hitler also once proposed building battleships armed with 800mm guns. He allowed himself to be dissuaded from that project when his admirals pointed out that a ship large enough to carry such monstrous guns would be too big to fit in any existing German harbour.
It should also be noted that an 800mm gun would be completely useless for salvo firing at sea by a moving ship against a moving target. In order to hit an enemy ship, a gun-armed vessel has to be able to shoot, observe where the shells land relative to the target, quickly correct its aim, and shoot again before the movement of the two ships invalidates the computed firing solution. The 16-inch guns of the Iowa class battleships could, with a well-drilled turret crew, be fired every 30 seconds, and the 18.1-inch guns of the Yamato class battleships could be fired every 45 seconds, which is adequate for naval combat. The Gustav/Dora 800mm (31-inch) guns – which had a rate of fire of 1 round every 30 to 45 minutes – were sixty times slower, and thus at best would only have had practical use (if 14 rounds per day can be called “practical”) as shore-bombardment vessels.
Had it been built, the P.1500 Monster would probably have been used in relatively static combat situations, such as the siege of Leningrad. Of the two, the P.1000 Ratte would have been the more flexible. Its projected top speed was a somewhat respectable 40 km/hr (25 mph)–over twice the speed of the Monster. The P.1000’s main armament consisted of two 280 mm guns (11 inches). This armament would have been a modified version of the turrets used on German ships.
It also featured a 128 mm secondary gun; and eight 20mm anti-air guns. It was to be powered with two u-boat engines. “The tank was to be provided with a vehicle bay sufficient to hold two BMW R12 motorcycles for scouting, as well as several smaller storage rooms, a compact infirmary area, and a self-contained lavatory system.”