Erwin Alois Robert Leder is an Austrian actor, born in St. Pölten, Lower Austria. He is best known for his role as Chief Mechanic Johann in Das Boot, a 1981 feature film directed by Wolfgang Petersen about a mission of one WWII U-Boat and its crew. In 2003, Leder appeared as the Lycan scientist Singe in the Gothic horror/action film Underworld.