HNLMS Jacob van Heemskerck 1908

Launched in 1906, HNLMS Jacob van Heemskerck was a coastal defence ship of the Royal Netherlands Navy. During the Second Castro Crisis, HNLMS Jacob van Heemskerck and the Holland-class cruisers Friesland and Gelderland were sent to patrol the Venezuelan coast.

By the start of World War Two, her active career was over the ship had her machinery removed and was converted into a floating battery ship renamed Batterijschip IJmuiden. After the German invasion, her crew scuttled the ship on 14 May 1940 to prevent her capture. However, on 16 July 1940 she was raised and towed to Amsterdam. From her she was moved to Kiel and converted into a floating anti-aircraft battery and renamed Undine.

Post-war she was found at Wilhelmshafen and returned to Dutch control. The ship was rebuilt as an accommodation ship and recommissioned on 23 February 1948. She was again renamed, this time as Neptunus. Neptunus performed this role until 13 September 1974 when she was decommissioned.