As I predicted Doenitz (now Vice Admiral), the British convoys and improved security techniques developed anti-submarine warfare. In March 1941, it was lost 5 submarines, and with them some of the best crews. On top of that, at the Royal Air Force were "long-range" anti-submarine aircraft, and Doenitz had to undergo operational zone further west, in the area between the British bases in Canada and Iceland, which did not reach the aircraft. The strategy of submarine warfare Doenitz was very simple: to sink as many enemy ships and do it as quickly as possible. If his submarine can sink ships faster than the British will be able to build them. The United Kingdom would be put to the knees. Doenitz was angry when Hitler decided to smuggle 20 submarines in the Mediterranean Sea, where they were supposed to ease the stranglehold on the British lines of communication states "Axis" in North Africa. Doenitz knew that the submarine that entered the Mediterranean, due to the strong westerly currents in the Strait of Gibraltar will not return back. He was able to dissuade the Fuehrer from doing so in the spring and summer, then Hitler reduced the number of boats up to 10, but the fall Doenitz had to obey orders. Because of this, he was forced to curtail large-scale action in the North Atlantic. Nevertheless Doenitz could not say until 7 October 1941, that year was unsuccessful. The Allies lost 1,299 ships (4,328,558 tons), of which half sunk submarines. Raeder and his staff found that Canadian and British shipyard annually produce only 1 600 000 tonnes. It became clear that Germany won the "Battle of the Atlantic."