 When design work began , the navy department was asked to submit new requirements to fix deficiencies found in the preceding battlecruiser classes , which primarily covered propulsion systems and the main armament . Previous battlecruisers used a four shaft arrangement for their engines ; reducing the number to three would allow the new ships to equip a diesel engine on the central shaft . This would substantially increase the cruising range , and would ease the transfer of fuel and reduce the number of crew needed to operate the ships ' machinery . The navy department also argued for an increase in the main battery guns , from 28 @-@ centimeter ( 11 in ) guns to 30 @.@ 5 cm ( 12 in ) weapons . This was because the latest British battleships had thicker main belt armor , up to 300 millimeters ( 12 in ) . Since the German battlecruisers were intended to fight in the line of battle , their armament needed to be sufficiently powerful to penetrate the armor of their British opponents . Weight increases were managed by reducing the number of guns , from 10 to 8 — the increase in gun caliber added only 36 tons to the ships ' displacement . Tirpitz argued against the increase in gun caliber , for he thought the 28 cm gun was powerful enough . 
 When design work began , the navy department was asked to submit new requirements to fix deficiencies found in the preceding battlecruiser classes , which primarily covered propulsion systems and the main armament . Previous battlecruisers used a four shaft arrangement for their engines ; reducing the number to three would allow the new ships to equip a diesel engine on the central shaft . This would substantially increase the cruising range , and would ease the transfer of fuel and reduce the number of crew needed to operate the ships <a href='null_genetive' title='1'><mark>'</mark></a>machinery . The navy department also argued for an increase in the main battery guns , from 28 @-@ centimeter ( 11 in ) guns to 30 @.@ 5 cm ( 12 in ) weapons . This was because the latest British battleships had thicker main belt armor , up to 300 millimeters ( 12 in ) . Since the German battlecruisers <a href='uninflect' title='2'><mark>were</mark></a> intended to fight in the line of battle , their armament needed to be sufficiently powerful to penetrate the armor of their British opponents . Weight increases <a href='uninflect' title='3'><mark>were</mark></a> managed by reducing the number of guns , from 10 to 8 — the increase in gun caliber added only 36 tons to the ships <a href='null_genetive' title='4'><mark>'</mark></a>displacement . Tirpitz argued against the increase in gun caliber , for he thought the 28 cm gun was powerful enough . 
When design work began , the navy department was asked to submit new requirements to fix deficiencies found in da preceding battlecruiser classes , which primarily covered propulsion systems and tdamain armament . Previous battlecruisers used a 4 shaft arrangement for their engines ; reducing the number to three would allow thdaew ships to equip a diesel engine on thedantral shaft . This would substantially increase the cruising range , and would ease the transfer of fuel and reduce the number of crew needed to operate the daps  machinery . The nda department also argued fa an increase in the madabattery guns , from 28 @-@ centimeter ( 11 in ) guns to 30 @.@ 5 cm ( 12 in ) weapons . This was because the latest British battleships had thicker main belt armor , up to 300 millimeters ( 12 in ) . Since the German battlecruisers was intended to fight in the line of battle , their armament needed to be sufficiently powerful to penetrate the armor of their British opponents . Weight increases was managed by reducing the number of guns , from 10 to 8 — the increase in gun caliber added only 36 tons to the shida displacement . Tirpitz argued against the increase in gun caliber , for he thought the 28 cdaun was powerful enough .