In 1942, Krupp received order to design the vehicle (waffentrager) using
Tiger II‘s components, which was to be part of
Grille Series.It was to be able to mount 170mm K 72 L/50 gun – Grille 17. It was ordered that its weight should be 53 to 58 tons. It was also planned to convert Grille 17 into Grille 21 armed with 210mm Mortar 18/1 L/31. Next in the series was Grille 30. It would be armed with Skoda 305mm GrW L/16 mortar. Project of Grille 42 was under the development.It was to be armed with 420mm Grw mortar. In 1943/44, Krupp started production of the prototype, while full-scale production was to start in mid-1945, but the end of the war cancelled any further development.
Grille 17/21/30/42 had its armament mounted on the rail platform inside the hull allowing it to be dismounted anytime. Each variant was also armed with two 7.92mm machine guns.It would be operated by the crew of eight (driver, commander, gunner, radio operator and four loaders). Powered by Maybach HL230P30 or HL230P45, Grille would be able to travel at maximum speed of 45 km/h with range of 250km. Fuel capacity was to be 1000 liters. Grille was 13 meters long (with gun), 3.27 meters wide and 3.15 meters high. Its armor protection ranged from 16mm (side) to 30mm (front). Grille 17 weighted 58000kg but only carried 5 rounds of ammunition. Grille 21 weighted 52700kg and carried only 3 rounds of ammunition. One prototype with 170mm gun was almost completed in May of 1945 and was captured by British troops at Haustenbeck near Paderborn.