Stuka attacks in particular devastated morale. On 15 September Heinkels of 3./Kampfgeschwader 55 destroyed eight locomotives in a single sortie. But the drive toward Moscow was halted during the two-month campaign, giving the defenders of the Soviet capital time to prepare defenses and move an enormous amount of industry eastward. During this month, Stuka pilot Hans-Ulrich Rudel sank the Soviet battleship Marat, during an air attack on Kronstadt harbour in the Leningrad area, with a hit to the bow with a 1000 kg armour-piercing bomb. Several other Soviet ships were sunk in this engagement. The Soviet Navy suffered heavy losses at the hands of the Luftwaffe during the war. By the end of 1941 the Luftwaffe had been reduced to just 30–40% of their original strength. The winter weather and the snow caused damage to aircraft, as engines seized and the oil and fuel froze inside the tanks. The Luftwaffe was losing as many aircraft damaged than in combat. The Luftwaffe also lost its General der Jagdflieger Werner Mölders, who was killed on 22 November in an accident, sapping morale even further. The Wehrmacht was now pushing toward Moscow and the Luftwaffe delivered its first raids over the capital but caused little damage. The Russians however were reinforced with fresh forces from Siberia including significant numbers of the T-34 tanks and nearly 1,000 aircraft. The Russian counter-attack, despite Luftwaffe intervention, succeeded in pushing the Germans back in December, saving Moscow and cutting off large parts of Army Group Centre. Faced with annihilation of its forces in the central sector, the Luftwaffe was ordered to increase its efforts, and it managed to prevent the destruction of the central front forces. The VVS now had numerical superiority. The failure of the Luftwaffe during Barbarossa was reflected in its losses, with 2,093 aircraft of all types being destroyed. Soviet losses stand at 21,200 destroyed, 10,000 in combat, of which 7,500 were shot down by the Luftwaffe fighters, who could now boast some of the top aces like Günther Lützow who had already surpassed the 100 victory mark; these scores were to increase over time. The successes of the German air arm were offset by the losses which unlike the Soviet Air Force could not be replaced easily as the German economy had not yet been put on a full war footing. Losses in personnel were also high and irreplaceable with 3,231 killed, 2,028