Frank R Turner and Trevor Adams

Report And Photos,

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Frank TurnerAs a result of German mining activity on the outbreak of war in September 1939, an urgent need arose to protect the waters of the Thames Estuary from small naval craft and aircraft sowing magnetic mines. The initial answer was the placing of four Naval Sea forts, each armed with two 3.7” Heavy AA guns and two 40mm Bofors guns, in the Estuary located as follows – one 7 miles off Harwich, Essex, one 7 miles off Frinton on sea, Essex, one 5 miles off Margate, Kent and one 12 miles off Herne Bay, Kent. The forts were designed by Guy Maunsell, a leading Civil engineer. The forts were constructed in a specially designed dock in Gravesend, Kent, towed to their designated locations, and sunk onto the sea bed. Each of these Forts was manned by 120 men and three Officers with crews rotating every six weeks to shore bases at Harwich for the Essex Forts and Sheerness for the Kent forts. These four Naval Forts were placed in the Thames between February 1942 and August 1942 and served throughout the war until finally abandoned in 1956. Of the four Forts only two currently exist, Roughs Tower off Harwich, now know as the Principality of Sealand and occupied by “Prince” Roy Bates and his family and Knock John abandoned and unoccupied off Herne Bay. Sunk Head fort off Frinton on Sea was blown up on Government instructions in the 1967 to stop Radio Pirate activity and Tongue Sands off Margate collapsed into the sea during a storm in 1996.

As a result of German air activity it was decided to build another type of fort to deter German aircraft from using the River Thames as a navigational aid to find the centre of London and the hugely important dockland area of that period. Guy Maunsell was again asked to a design a suitable structure to meet this need and this time he came up with a totally different answer in the shape of seven towers joined together by catwalks. The seven towers consisted of a Bofors Tower with two 40mm Bofors guns, four Towers each with two 3.7” HAA guns, a Control Tower housing Radar, and a Searchlight Tower. The Towers were built at The Red Lion Wharf site in Gravesend and towed down river and then lowered by hand winch onto the sea bed, each tower taking up to eight hours to be placed into position. The first set of seven towers were placed at The Nore between May and July 1943, the second set, Redsand Fort between July and September 1943 and the final set, Shivering Sand Fort between September and December 1943. Crewed initially by a crew of 165 men spread out in the seven towers, this figure was increased to 265 men after June 1944 when the German Luftwaffe started to use the V1 Flying Bomb (Doodlebug). These new weapons were much faster than aircraft of that period and it was necessary to have men at their gun positions to have a chance of hitting them. The period on board for the crew was four weeks followed by a ten day break ashore at The Drill Hall, Gillingham, Kent. The unit was know as The First A.A. Fort Regiment R. A. (Thames) which was disbanded at the end of the war and replaced by the “A.A. Fort Maintenance Detachment R.A.”. In wartime, supplies were ferried out to the Forts by the R.A.S.C. Water Transport company from Sheerness in Kent using small armed trawlers. During the wartime period all of the forts in the Thames Estuary were responsible for shooting down 21 aircraft and 30 plus “Doodlebugs”.

The maintenance crews were in occupation from May 1945 until April 1956 when it was decided to remove the guns and abandon the Forts. On March 1st, 1953, a ship, the “Baalbeck” ran into the Nore group of towers in thick fog and knocked over the Bofors tower and a gun tower killing four of the installed maintenance crew. Subsequently in 1959 the Nore group of towers were removed and scrapped.

Another accident happened in 1963 when in June a ship, The Ribersborg, crashed into the Shivering Sands Fort and demolished a gun tower. Fortunately no one was on board at the time and so there were no casualties. Thus Shivering Sands Fort consists today of only six towers.

This left the Red Sands and Shivering Sands Forts remaining out of the original three forts. In 1964, shortly after Radio Caroline commenced broadcasts Shivering Sands towers were occupied by David ‘Screaming Lord’ Sutch from where he operated Radio Sutch [subsequently sold to his manager, Reg Calvert, who changed the name to Radio City]. Redsand towers were occupied by the operators of Radio Invicta [no connection with the present station of the same name]. This became KING Radio, following the death of Invicta’s owner, Tom Pepper, and finally Radio 390, a hugely successful ‘sweet music’ station. following the period of occupation by the radio pirates from 1964 to 1967 the Forts were ‘made safe’ by the Admiralty by removing access ladders and catwalks to deter people from climbing on board.

Today, Redsand Fort as the only complete Army fort as built in wartime, is the focus of attention by Project-Redsand, a group of enthusiasts with the aim of reinstating the fort to its original built condition. Having had an underwater survey carried out by the Port of London Authority at a cost of approximately 3,000, work has progressed by installing a new access ladder and landing platform to the G1 Gun Tower, thanks to the generosity of Mowlem marine of Northfleet. Built at a cost of approximately 30,000 this access ladder now enables project members to board the tower to begin restoration. A new survey of the above water structures is being conducted by Taylor Woodrow and once this is complete, further work of renovation will be undertaken. Restoration of this structure will enable to Fort to take its place as a monument to the ingenuity of Guy Maunsell, who used the Army Fort design to pave the way for the exploration rigs used in the North Sea in the 1950’s.

Further information regarding Project Redsand, news and recent pictures can be found on 

NB. Military equipment installed on the Forts consisted of 3.7” H.A.A. guns Mk 2c with automatic loaders by Mollins of Deptford. radar No 3 Mk2 subsequently updated and modernized to Radar No 3 Mk 7. Sperry Predictors No 11 and Searchlight No 2 Mk2.

 Frank R Turner 2006

Maunsell Sea Forts