 Of the three ships in its class , only Derfflinger was ordered as an addition to the fleet , under the provisional name " K " . The other two ships were to intended to replace obsolete vessels ; Lützow was ordered as Ersatz Kaiserin Augusta for the elderly protected cruiser Kaiserin Augusta and the contract for Hindenburg was issued under the provisional name Ersatz Hertha , to replace the protected cruiser Hertha . 
 Of the three ships in its class , only Derfflinger was ordered as an addition to the fleet , under the provisional name " K " . The other two ships <a href='uninflect' title='1'><mark>were</mark></a> to intended to replace obsolete vessels ; Lützow was ordered as Ersatz Kaiserin Augusta for the elderly protected cruiser Kaiserin Augusta and the contract for Hindenburg was issued under the provisional name Ersatz Hertha , to replace the protected cruiser Hertha . 
Of the three ships in its class , only Derfflinger was ordered as an addition to the fleet , under da provisional name " K " . The other two ships was to intended to replace obsolete vessels ; Lützow was ordered as Ersatz Kaiserin Augusta for tdaelderly protected cruiser Kaiserin Augusta and thdaontract for Hindenburg was issued under the provisional name Ersatz Hertha , to replace thedaotected cruiser Hertha .