• 
  Pat O'Brien

  Chief Michael 'Mike' Mallory
• 
  Jane Wyatt

  Myra Mallory
• 
  William H. O'Brien

  Clerk at hearing
• 
  Frank Jenks

  Sampier
• 
  Hans Schumm

  U-51 captain recognizing Kroner
• 
  Edgar Dearing

  Bud, chief petty officer
• 
  Jackie Cooper

  Joe 'Babe' Duttson
• 
  Ray Collins

  Captain McCall

• 
  Malcolm Waite

  Top lookout
• 
  Stanley Andrews

  Judge advocate
• 
  William Haade

  Pier 7 guard
• 
  Helmut Dantine

  Frightened young German seaman
• 
  Egon Brecher

  U-Boat commander
• 
  Cyril Ring

  Mr. Reynolds, first officer
• 
  Hans Heinrich von Twardowski

  U-Boat captain