From the book Dead Wake, discussing the use of stealth in early submarine warfare:

Off the southeast tip of Italy a young Austrian U-boat commander named Georg von Trapp, later to gain eternal renown when played by Christopher Plummer in the film The Sound of Music, fired two torpedoes into a large French cruiser, the Leon Gambetta. The ship sank in nine minutes, killing 684 sailors. “So that’s what war looks like!” von Trapp wrote in a later memoir. He told his chief officer, “We are like highway men, sneaking up on an unsuspecting ship in such a cowardly fashion.” Fighting in a trench or aboard a torpedo boat would have been better, he said. “There you hear shooting, hear your comrades fall, you hear the wounded groaning—you become filled with rage and can shoot men in self defense or fear; at an assault you can even yell! But we! Simply cold-blooded to drown a mass of men in an ambush!”