These visualisations of Guy Maunsell's Red Sand Fort in the Thames Estuary have been released to coincide with a fundraising event to save the Second World War relics.
An ambitious attempt is being made to rescue the fort -a group of seven towers which rise out of the sea on concrete legs and were originally built to ward off the threat of a German invasion.
However, those leading an effort to restore the fort need to resolve who actually owns it before the salvage attempts can proceed. The Crown Estate which, according to the rescue team, owns the seabed; the Department of Transport, which is responsible for navigation in coastal waters; and English Heritage are all currently in discussions.
The military installation was originally built in 1943 and was designed by Maunsell, a noted civil engineer of his day. The basic design later became a template for the first North Sea drilling rigs.
The identical structures were erected in haste to defend London from German bombing raids and to help fight off a sea-borne invasion from occupied France.
After being abandoned by the Ministry of Defence in 1956, the forts became a haven for pirate radio broadcasters, including former Monster Raving Loony Party leader Screaming Lord Sutch.
This weekend an exhibition at Whitstable Castle will include presentations from those behind the effort to return the fort to its former glory. The team is headed up by freelance broadcast engineer Robin Adcroft, and includes Maunsell expert Frank Turner.
The images have been produced by freelance designer Zachery Rensburg.by Rob Sharp