What percentage of u-boats were sunk in World War 2?

Answer 1

Over 90% of German U-boats were sunk by the end of the war. The early days were remembered fondly by the submariners as the "happy times". By 1943 the Allies all-out efforts to develop anti-submarine warfare were paying off, though, and U-boats began to go down with greater and greater frequency. The Americans and British built hundreds of "subchasers" - small ships of different types, from patrol craft, corvettes, frigates, destroyers and destroyer escorts, to protect convoys and hunt subs. "Jeep carriers" were small aircraft carriers made by building a flight deck on top of a Liberty ship hull. These could handle about twenty aircraft and the planes carried bombs and depth charges to attack submarines. These also escorted convoys and closed the "air gap" in the middle of the ocean, where long-range land-based planes had not been able to reach. Radar was especially deadly as it was developed. Submarines had to surface each night to recharge their batteries, which powered the ship underwater. Allied bombers equipped with radar would swoop down when they surfaced, turn on powerful searchlights mounted on the wings, and bomb the ship. The Germans developed a radar detector,called Metox, but it put out a signal that the Allies figured out how to pick up, so they were able to find the surfaced subs without using their own radar, and surprise them, betrayed by their own warning system. Only about 7% of German submarine sailors survived the war.