High Quality Content by WIKIPEDIA articles! The Nassau class were a group of four German dreadnought battleships built for the Imperial Navy. They were the German response to the introduction of the "all big gun" British Dreadnought. The class was composed of Nassau, Rheinland, Posen, and Westfalen. All four ships were laid down in mid-1907, and completed between May and September 1910. Compared to their British contemporaries, the Nassau-class ships were lighter and had a wider beam. They were two knots slower, because the German ships retained vertical triple-expansion engines as opposed to the high-power turbine engines adopted by the British. The ships also carried smaller main guns—11-inch (280 mm) guns rather than the 12-inch (305 mm) guns mounted on the British ships.