Tragedy on the USS West Virginia

A patrol hears a mysterious tapping sound and discovers it comes from a sunken ship. The patrol faces a moral dilemma as rescuing the trapped person could lead to their death. Eventually, the ship is moved to a dry dock, revealing three bodies in an airtight room. The banging sound continued until Christmas Eve, long after the sailors were presumed dead.

How did the authorities respond to the banging sound initially?

What was the final discovery made when the ship was moved to a dry dock?