 The new 41 cm turrets installed during their reconstruction were more heavily armored than the original ones . Face armor was increased to 460 mm ( 18 in ) , the sides to 280 mm ( 11 in ) , and the roof to 230 – 250 mm ( 9 – 10 in ) . The armor over the machinery and magazines was increased by 38 mm ( 1 @.@ 5 in ) on the upper deck and 25 mm on the upper armored deck . The torpedo bulges added at the same time were 13 @.@ 5 meters ( 44 ft 3 in ) high and 2 @.@ 84 meters ( 9 ft 4 in ) deep . They were divided into four compartments , the lower two of which were filled with oil and the others remained empty . These additions increased the weight of each ship 's armor to 13 @,@ 032 metric tons ( 12 @,@ 826 long tons ) , 32 @.@ 6 percent of their displacement . In early 1941 , as a preparation for war , the uppermost compartment of the bulges was filled with sealed steel crushing tubes and the barbette armor of both ships was reinforced with 100 mm armor plates above the main deck and 215 mm ( 8 @.@ 5 in ) plates below it . 
