time caused a decline of 20 percent of aircraft output, recovered. The effect on general industrial production was not significant. In five months of bombing docks and ports in 1941, only some 70,000 tons of food stocks were destroyed, and only one half a percent of oil stocks. Damage to communications was quickly repaired. Everywhere except in the aircraft industry the loss was too small a fraction of total output to matter seriously. In early June 1941, the majority of German bomber units moved eastward to the soon-to-be Eastern Front, in preparation for Operation Barbarossa. Luftflotte 2, with elements of Sperrle's air fleet—from IV and IV Fliegerkorps—were reassigned. Battle of the Atlantic Sperrle had been involved in the war at sea since the first phase of the Battle of Britain. He received an OKL directive on 20 October 1940 ordering him to attack shipping once again in the Thames Estuary. He ordered his dive-bombers into this service, but they were rapidly neutralised in November by a "dynamic defence". The most effective support for the U-boat campaign came from attacking ports, which Directive 23, issued on 6 February 1941, had ordered the German air fleets to do. Direct support to the Kriegsmarine in the Battle of the Atlantic was haphazard; successes were won by accident rather than by design. In late May 1941 Luftflotte 3 made a sole contribution to the surface fleet, when it tried, in vain, to save the battleship Bismarck. Within days, 41 of the 48 bomber groups engaged in operations over Britain departed for the soon-to-be Eastern Front in preparation for Barbarossa. Of the remaining seven, five were to support the Kriegsmarine in the Battle of the Atlantic under the command of Fliegerführer Atlantik (Flying Leader Atlantic). The Atlantic command came under Sperrle's control upon formation but was subordinated to Sperrle officially on 7 April 1942. The name of the command was misleading, for it was tasked with maritime interdiction operations all around the British coast besides operating deep into the Atlantic. Only two bomber groups remained under Sperrle's command at the end of 1941 for direct attack on Britain. The anti-shipping mine-laying force around Britain did not receive the support it required through the war, and the German effort remained half-hearted. Sperrle protested to the OKL, OKW and Göring upon the dissipation of mine-laying operations through 1941 and 1942. Greim's air corps was designated as leader