 A new construction technique was employed to save weight . Previous battlecruisers were built with a combination of transverse and longitudinal steel frames ; the Derfflinger @-@ class ships <unk> with the transverse frames and used only the longitudinal ones . This enabled the ship to retain structural strength and a lower weight . As with all preceding capital ships , the outer hull spaces between the hull wall and the torpedo bulkhead were used for coal storage . 
