Mike Farrough
Christine Blaine
John Morgan
Larry Perrin, alias Larry Ross
Dr. Adolph Behrens
Charles Atterbee
Tommy Malone
Mrs. Winslow
Professor Mudge
Mrs. Mudge
Ship's Mate Penney
Captain James P. Hollister
Ship's Mate Jones
Ship's Chief Engineer Anderson
Submarine First Officer
Submarine Radio Operator
Ship's gunnery officer
First Mate
Perrin's Henchman at Dock
Agent
Detective
Detective
Sailor
Sailor
German Sailor
Ship's Lookout
Mrs. Hollister
German Sailor
German Sailor
Man
Submarine Gunner
Sailor
Sailor
Submarine Commander