An astonishing 75% of all WW2 German submariners never returned from their missions, the highest casualty rate of any service I know of. I believe the phenomenon of 'breaking its back' with an explosion directly under the target vessel from a giant air bubble was first noticed when acoustic torpedoes were used which fixed on propeller noise rather than direct contact. I think intentional use of this method was developed after WW2.
My significant other's father served on a US sub when he was 18, in 1945. Being an African American from North Carolina his official designation was mess steward, although he was actually used in other capacities. That's how it was in the US military in 1945. I've seen his diary, which details how he helped sail a surrendered high tech German sub from Germany to New London just after the war. The captain gave him the ship's rifle as a trophy.
My significant other's father served on a US sub when he was 18, in 1945. Being an African American from North Carolina his official designation was mess steward, although he was actually used in other capacities. That's how it was in the US military in 1945. I've seen his diary, which details how he helped sail a surrendered high tech German sub from Germany to New London just after the war. The captain gave him the ship's rifle as a trophy.