Continuity mistake: When Luther Billis is parachuting out of the plane, he is seen with a pistol in his hands. Once he is in the rubber boat and starts paddling, however, the pistol has become a rifle.
Continuity mistake: When doing the "there is nothing like a dame" dance number on the beach, Ray Walston from cut to cut has his shirt either buttoned up or unbuttoned.
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