HM Fort Roughs

HM Fort Roughs was one of several World War II installations that were designed by Guy Maunsell and known collectively as His Majesty's Forts or as Maunsell Sea Forts; its purpose was to guard the port of Harwich, Essex, and more broadly, the Thames estuary. This 4500 ton artificial naval installation is similar in some respects to "fixed" offshore oil platforms. It is situated on Rough Sands, a sandbar located approximately 11 kilometres (6 nmi) from the coast of Suffolk and 13 kilometres (7 nmi) from the coast of Essex. Today it is the location of the self-proclaimed and unrecognised state, the Principality of Sealand.

As a contemporary historical society notes, Fort Roughs or the "Rough Towers" was "the first of originally four naval forts designed by G. Maunsell to protect the Thames Estuary." The artificial sea fort was constructed in dry dock at Red Lion Wharf, Gravesend, in the year preceding and into 1942.

This artificial naval installation is similar in some respects to early "fixed" offshore oil platforms. It consisted of a rectangular 168-by-88-foot (51 by 27 m) reinforced concrete pontoon base with a support superstructure of two 60-foot (18 m) tall, 24-foot (7.3 m) diameter hollow reinforced concrete towers, each roughly 3.5 inches (9 cm) thick; overall weight is estimated to have been approximately 4500 tons. The twin concrete supporting towers were divided into seven floors, four for crew quarters; the remainder provided dining, operational, and storage areas, e.g., for several generators, and for fresh water tanks and antiaircraft munitions. There was a steel framework at one end supporting a landing jetty and crane which was used to hoist supplies aboard; the wooden landing stage itself became known as a "dolphin".

The towers were joined above the eventual waterline by a steel platform deck upon which other structures could be added; this became a gun deck, on which an upper deck and a central tower unit were constructed.QF 3.75 inch anti-aircraft guns were positioned at each end of this main deck, with a further two Bofors 40 mm anti-aircraft guns and the central tower radar installations atop a central living area that contained a galley, medical, and officers quarters.

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