 The five Wittelsbach class battleships were armored with Krupp steel . Their armored decks were 50 millimeters ( 2 @.@ 0 in ) thick , with sloped sides that ranged in thickness from 75 to 120 mm ( 3 @.@ 0 to 4 @.@ 7 in ) . The sloped section of the deck connected it to the main armored belt , which was 225 mm ( 8 @.@ 9 in ) in the central citadel , where the ship 's vitals were . This included ammunition magazines and the propulsion system . The belt was reduced to 100 mm ( 3 @.@ 9 in ) on either end of the central citadel ; the bow and stern were not protected with any armor . The entire length of belt was backed by 100 mm of teak planking . 
