1920 - The Nab Tower
September. The Nab Tower was sunk in position and replaced the Nab Light ship. During 1918 the Admiralty planned to close the Straits of Dover to all but friendly shipping and prevent German U-boats using it as a passage to the English Channel.
The plan entailed six gigantic towers linked by steel boom netting. Each tower costing £1 million. The war ended within a few months and only one tower was completed and so the Admiralty came up with an alternative plan to use it as a navigation beacon in place of the Nab lightship.