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