Dukhov's team was instructed to create a stopgap KV tank, the KV-85, which was armed with the 52-K-derivative gun of the SU-85, the 85 mm D-5T, that proved capable of penetrating the Tiger I from 1,000 m (1,100 yd). The KV-85 was created by mounting an Object 237 turret on a KV-1S hull. To accommodate the Object 237 turret, the KV-1S hull was modified, increasing the diameter of the turret ring with fillets on the sides of the hull.