The easier name for them was U-boats. They were the thorn in the side of the Allies, notorious for attacking civilian and military vessels. While there were many boats that bore the name U-boat, the Germans built them fast and slightly different with every generation. During the course of the was the Allies sank almost 800 of these things, which were usually filled with inexperienced German crews. Of the 40,000 German seamen, about 75 percent died at sea.
Army Air Corps
Most people credit the overwhelming use of flight during the war for the new branch we called the Air Force. The U.S. Air Force didn’t exist as we know it today when World War II broke out. We had something called Army Air Corps. We lost so many of our Air Corpsmen during WWII, the chances of survival were less than 30 percent. It was a statistic we aimed to correct after that war.