 "U-9" was renumbered by the Germans as "U-68" when her class was redesignated as the Type U 66.The Imperial German Navy had the submarines redesigned and reconstructed to German standards, which increased the surface displacement by and the submerged by .The torpedo load was increased by a third, from 9 to 12, and the deck gun was upgraded from the gun originally specified to an SK L/30 one.