 She was armed with four 26 cm ( 10 @.@ 2 in ) L / 22 guns mounted in a pair of gun turrets placed amidships . As built , the ship was also equipped with two 17 cm ( 6 @.@ 7 in ) L / 25 chase guns . After being rebuilt in 1888 – 1890 , her armament was increased by six and later ten 8 @.@ 8 cm ( 3 @.@ 5 in ) L / 30 quick @-@ firing guns , a pair of machine guns , and five 35 cm ( 14 in ) torpedo tubes , all submerged in the ship 's hull . Preussen 's armor was made of wrought iron and backed with teak . The armored belt was arrayed in two strakes . The upper strake was 203 mm ( 8 @.@ 0 in ) thick ; the lower strake ranged in thickness from 102 to 229 mm ( 4 @.@ 0 to 9 @.@ 0 in ) . Both were backed with 234 to 260 mm ( 9 @.@ 2 to 10 @.@ 2 in ) of teak . The gun turrets were protected by 203 to 254 mm ( 8 @.@ 0 to 10 @.@ 0 in ) armor on the sides , backed by 260 mm of teak . 
