Cast
Stanley Logan
Captain James P. Hollister
Erwin Kalser
Dr. Adolph Behrens
Edgar Buchanan
Charles Atterbee
Frank Baker
Detective
Constance Bennett
Christine Blaine
Marjorie Gateson
Mrs. Winslow
Olaf Hytten
Agent
Pat O'Brien
Mike Farrough
Alan Baxter
Larry Perrin, alias Larry Ross
Dick Rich
Perrin's Henchman at Dock
Frank Sully
Tommy Malone
Francis Pierlot
Professor Mudge
Jessie Busley
Mrs. Mudge
Don Beddoe
Ship's Chief Engineer Anderson
Norbert Schiller
Submarine First Officer
Wyndham Standing
Man
John Halliday
John Morgan
Melville Cooper
Ship's Mate Penney
Bruce Bennett
Ship's gunnery officer
Douglas Gordon
Ship's Lookout