On examination of the "Prince of Wales" after her encounter with the German battleship Bismarck and the heavy cruiser , three damaging hits were discovered which had caused about 400 tons of water, from all three hits, to enter the ship. One of these hits, fired from "Bismarck", had penetrated the torpedo protection outer bulkhead in a region very close to an auxiliary machinery space causing local flooding within the SPS, while the inner, 1.5-inch ( 2x19 mm) D-steel holding bulkhead, however, remained intact, as the German shell was a dud. The German shell would have actually exploded in the water if its fuse had worked properly, due to the depth which the shell had to dive before striking the "Prince of Wales" under her armoured belt.