Cast
William Collier Sr.
Mugs O'Flaherty (uncredited)
Ferdinand Schumann-Heink
Adolph Brucker (uncredited)
Larry Kent
Lt. 'Mac' McGregor
Harry Strang
Gunner and drill sergeant (uncredited)
Steve Pendleton
Ens. Richard 'Dick' Cabot (as Gaylord Pendleton)
John Loder
Franz Shiller
Maurice Murphy
Merkel (uncredited)
Henry Victor
Baron Ernst von Steuben (U-boat commander)
Joseph Depew
Naval Reservist (uncredited)
Hans Fuerberg
Fritz Kampf (Second Officer of U-172) (uncredited)
George Harris
Naval Reservist/Swimmer and Diver (uncredited)
Jack Murphy
Naval Reservist (uncredited)
Harry Tenbrook
Winkler (uncredited)
ジョージ・オブライエン
Cmdr. Robert 'Bob' Kingsley
Marion Lessing
Anna Marie Von Steuben
Walter McGrail
Chief Joe Cobb
Mona Maris
Fraulein Lolita
Walter C. Kelly
Chief Mike 'Guns' Costello
Warren Hymer
'Lug' Kaufman
Francis Ford
Eric - Captain of Trawler (uncredited)
Edward Peil Jr.
Naval Reservist (uncredited)
Nat Pendleton
'Butch' Wagner (uncredited)