Question: I have heard that the role of Bloody Mary was dubbed in this movie. Who dubbed her, and why isn't that person listed in the credits (given that Giorgio Tozzi, who dubbed Emile de Becque, is credited)? Also, were Nellie and Lt. Cable dubbed? Again, no one is credited, but their singing voices sound dubbed to me. Can anyone shed some light on this?
Question: The movie was made in 1958, why does the calendar in police station show July 1957?
Answer: Because movies aren't always set in the year they're released. Absent any conflicting information, the assumption must be that the events of the movie take place around July 1957.
Question: At the beginning what was wrong with the young sailor drawing number 7 in the money draw?
Answer: Sailors are very superstitious, they considered it a bad omen. Number 7 is an area of the ocean where most ships and subs have gone down.
Answer: See http://www.imdb.com/title/tt0052225/fullcredits#cast. Bloody Mary's singing voice is Muriel Smith, Lt. Cable's is Bill Lee. Mitzi Gaynor (Nellie) does her own singing. For most of these "on-location" musicals, the singing is recorded in a studio, so even the actors who do their own singing are, in effect, dubbed by themselves.
Myridon