German Flakschiff Ariadne

HNLMS Hertog Hendrik was launched on 5 January 1904 as the Koningin Regentes-class coastal defence ship of the Royal Netherlands Navy. In 1939, she was obsolete and had been reclassified and renamed as the floating battery ship Batterijschip Vliereede. In 1940 she was laid up and waiting to be scrapped.

The hulk was captured by German forces during the invasion of May 1940, but was sunk after being attacked by British aircraft in June 1940. Raised by the Germans in October 1940, she underwent a conversion to an Anti Aircraft battery from 1941 to 1943. On completion as a flakschiff, she was renamed Ariadne.

Post war she was returned to the Netherlands, converted to an accommodation ship and renamed Hertog Hendrik. She was finally decommissioned in 1968 and sold for scrap in 1969.