O 6 was a unique patrol submarine of the Royal Netherlands Navy for European home waters.

The ship was built by De Schelde shipyard in Flushing.

[2] The submarine was ordered on 8 May 1913 and in May 1914 the O 6 was laid down in Flushing at the shipyard of De Schelde.

During World War I the ship was based in Den Helder.

Vening Meinesz for gravity measurements in the North Sea.