British firm Vickers built a dock for submarines for German account according to the Dutch magazine Marineblad dated 1906-1907 no. 6

An item referred to the magazine Schiffbau reporting that the British firm Vickers, England built a dock for submarines for Germany with a lifting capacity of 500 tons and as dimensions 250 x 50 x 28 (height) feet with side pontoons with a length of 200 feet.