The Rough Towers

Fort Specifications:

Approx 10 miles off the Harwich seafront, the Rough Towers was the first of originally 4 naval forts designed by G.Maunsell to protect the Thames Estuary. The forts consisted of 2 re-enforced concrete towers, topped with a steel platform. The whole fort was constructed on a re-enforced concrete pontoon, which was floated into position and then sunk onto an unprepared seabed.

The forts were all constructed to the same specifications consisting of 2 towers standing 18 metres in height, 7 metres in diameter. Each tower was split into 7 floors of which 4 of these floors were used for crews quarters. The wall thickness of the reinforced concrete towers was 9 centimetres. On top of the towers there was a main deck consisting of anti-aircraft guns one positioned at each end of the deck. In the centre of the deck was the officers quarters, medical room & kitchen. Mounted on the roof of this living area were 2x 40 mm Bofors anti-aircraft guns also in the centre of the roof the operations control room was sited. On the roof of this 2 forms of radar were installed.

In addition to this equipment the forts were self sufficient of freshwater this being housed in tanks mounted within the 2 towers. For electricity the forts were supplied with 3 diesel generators, 2 of these being used as the main power supply & the 3rd as a backup generator. Each fort was supplied with its own heating & forced ventilation air supply.

The total height of the fort was 33.5 metres, weighing approximately 4500 tons & having a crew of 120 personnel although during the course of the war this number was reduced. To assist with the landing of crew & provisions each fort was equipped with its own wooden landing stage called a Dolphin.

Pontoon dimensions 168' loa, 88' beam, 14' keel to deck. approx 2000 tons. Towers 24' diam 60' above pontoon deck.

Rough Towers sunk 11th Feb 1942 in 37' water.

A 4' temp. wooden wall to stop excessive flooding during tow was not removed completely prior to flooding, the port side wall still being intact at the time of influx, causing the pontoon to flood to stbd. This caused the pontoon to sink stbd side first as opposed to bow first. The stbd bow hit the sea bed with the tower listed 30 degrees to stbd, before correcting herself. There were 100 men aboard at the time !

Built at Red Lion Wharf Gravesend

Supplied by HMS Badger at Parkeston Quay along with Sunk Head Towers. The other two navy forts Nore & Knock John being serviced from Sheerness.

Animation showing the sinking of a fort: