SMS Lützow was the second Derfflinger-class battlecruiser built by the German Kaiserliche Marine (English: Imperial Navy) before World War I. Ordered as a replacement for the old protected cruiser Kaiserin Augusta, Lützow was launched on 29 November 1913, but not completed until 1916. Lützow was a sister ship to Derfflinger from which she differed slightly in that she was armed with an additional pair of 15 cm (5.9 inch) secondary guns and had an additional watertight compartment in her hull.