How did the Germans use their submarines?

Answer 1

During World War 2, the Germans wrote the book on submarine warfare. They hunted and sunk thousands of tons of Allied shipping, killing many merchant mariners in the process. Commanders of the German submarine forces sent their boats out to patrol specific geographic points, constructing a "net" of sorts through which Allied shipping would be obliged to pass. If a convoy was detected, the U-boats could be ordered to converge and form what were called wolf packs (Wolfsrudel, which arose from the German rudel). They would then attack a convoy en masse. The US adopted the tactics and used them against the Japanese in the Pacific theatre. The Kriegsmarine set up a logistics system that allowed them to supply their boats at remote points at sea. This was in addition to support provided at the heavily bunkered submarine pens, built to be impervious to bombs, that were located on the German coast, in Norway, and it several places in France. Strategy and logistics were well suited to the delivery of ordinance, food and other supplies to the boats as far away as the coast of South America and southern Africa. All in all, the Germans played their trumps in U-boat strategy and tactics to fine advantage, and only the press of numbers on the part of the Allies was able to break their grip on the sea lanes. As attrition began to trim their numbers, more and more of the German crews never returned, and were left on "eternal patrol" as the war wound down.