While we were looking for old post cards to post, we found this picture of the Nab Tower



Trinity House writes about this peculiar construction:
This light is responsible for guiding ships of all sizes and nationalities into the deep water channel for Portsmouth and Southampton. The story of its strange origin goes back half a century. In the early part of 1918 attacks by German U-boats on our merchant fleet caused the Admiralty so much anxiety that it was decided to take strong, if unorthodox, counter measures and a startling plan was drawn up by "backroom" scientists. This was to sink a line of eight fort like towers (each costing £1 million) across the straits and to link them with steel boom nets, with the idea of closing the English Channel to enemy ships. About 3,000 civilian workmen were brought to a quiet backwater at Shoreham and work began almost at once on two of these towers - each 40 feet in diameter with latticed steel work surrounding the 90 foot cylindrical steel tower and built on a hollow 80 foot thick concrete base designed to be flooded and sunk in about 20 fathoms. The vast honey combed concrete base was shaped with pointed bows and stern for easy towing.
One tower was completed when the war finished in November, and the other half finished giant was broken up for scrap. After much thought it was decided to use the solitary "white elephant" to replace the old Nab Light Vessel by sinking it at the eastern end of the Spithead approaches, also serving as an invaluable naval defence post, if required.
On a calm day in 1920 two paddle wheel tugs towed the tower to a position near the light vessel. There were many anxious moments as the base was opened to the sea, but this brain child of a civilian designer, Mr. G. Menzies, performed exactly as planned and settled without incident, kept steady by the immense volume of water inside the base.
Staffed since 1920 as an off-shore lighthouse, by three keepers who were relieved monthly, the station was automated in 1983 and converted to solar powered operation in 1995. The latter involved the installation of a complete new proprietary lantern manufactured by Orga.



Thought this might interest some of you ...