 As with other German capital ships of the period , Blücher was equipped with Krupp cemented armor . The armored deck was between 5 – 7 cm ( 2 @.@ 0 – 2 @.@ 8 in ) in thickness ; more important areas of the ship were protected with thicker armor , while less critical portions of the deck used the thinner armor . The armored belt was 18 cm ( 7 @.@ 1 in ) thick in the central portion of the ship where machinery , ammunition magazines , and other vitals were located , and tapered to 8 cm ( 3 @.@ 1 in ) in less important areas of the hull . The belt tapered down to zero at either end of the ship . Behind the entire length of the belt armor was an additional 3 cm ( 1 @.@ 2 in ) of teak . The armored belt was supplemented by a 3 @.@ 5 cm ( 1 @.@ 4 in ) torpedo bulkhead , though this only ran between the forward and rear centerline gun turrets . 
