 The five ships of the Wittelsbach class each had three three @-@ cylinder triple expansion steam engines . The outer engines drove a three @-@ bladed screw that was 4 @.@ 8 m ( 15 ft 9 in ) in diameter ; the central shaft drove a four @-@ bladed screw that was slightly smaller , at 4 @.@ 5 m ( 14 ft 9 in ) in diameter . To produce steam to power the engines , each ship had six marine @-@ type boilers , with the exception of Wettin and Mecklenburg , which had six Thornycroft boilers , along with six transverse cylindrical boilers . Steering was controlled by a single large rudder . 
