More information : (TA 3702 0909) Bull Sand Sea Fort.
The larger of two island forts in the Humber Estuary, Bull Sand Sea
Fort, or the Northern Fort as it was known in code (for security
reasons), is a remarkable structure. As with its sister fort at Haile
Sands the fort was ordered in 1914 to provide extra protection for
Humber shipping.
Construction was started in 1915 when interlocking steel piles 74 ft long were driven into the river bed in a circular pattern. Another
row, 27 ft inside the first, was then added with radial arms
connecting the two sets. This formed eight outer compartments and a single inner compartment. These compartments were then excavated to a depth of 20 ft below the river bed, and the outer compartments were filled with concrete. The inner compartment was filled with chalk rubble and then capped with 14 ft of concrete. To re-inforce the foundations further steel bars in two transverse rows were laid over the concrete cap and concrete was deposited over the whole foundation area up to floor level. While the concrete was being poured, shutters were left in the concrete to form the cellar floor. The final apron was 5 ft above high water, and would leave a clear apron of 9 ft around the superstructure. Around 15000 cubic yds of concrete were deposited in the foundations, and the piles weighed 960 tons in total.
To stop sand from scouring around the foundations, chalk was
deposited to a width of 30 ft on the river bed around the fort. This
divided the scour into two channels, these themselves were then
filled with rubble to prevent scour within them. 45000 tons of
material was used during this process.
The superstructure of the fort is a circular building with an
external diameter of 82 ft. It is formed from a double 3/8 inch thick
steel plate set 18 inches apart, the cavity was filled with concrete.
The seaward side of the fort was plated with 12 inch thick armour
plate, which covered an arc of 99 degrees rising the full height of
the superstructure.
The fort had four basic levels, the cellar, bottom floor, first
floor, and the roof gundeck. The cellar contained vital stores, such
as the magazine, shell store, coal store, and beer store. The central floors were mainly filled with quarters for different ranks, but also engine rooms and kitchens; the four external searchlight emplacements were accessible from the first floor. As the central levels were very enclosed, the fort had to have an air exchange system, based on the `plenum system', it ensured the air was changed every 10-15 minutes. The 90 cm searchlights were built in four sponsons on the outside of the fort.
The gunfloor of the fort was the roof. This consisted of four 6 inch
Mk7 guns on Mk2 mountings. These were sited in an arc of 160 degrees and a radius of 33 ft, leaving virtually no dead water. The seaward guns were enclosed in a bullet proof steel enclosure called a closed barbette, while the others were in open barbette emplacments. Ready- use ammunition was kept by the guns, and more could be brought via the electric lift. Also on the roof was an armoured structure forming the battery command post and electric light directing station, with two rotating armoured turrets, each with a 9 inch Barr and Stroud range finder on top. After the use of over 46000 tons of concrete and steel, the fort was complete in 1919.
The fort spent the inter-war years being maintained by a peacetime force of one officer and twelve other ranks. It was also used by the Territorial Army for seaward firing practise. The fort was temporarily re-activated during the Munich crisis, and was back on a full time basis once the war started. It was first used to support the examination service, an anchorage bing established to the south.
In May 1940 the rear guns were removed to be replaced by 6 pounder anti motor torpedo boat weapons. Also at this time, a brick recreation hut was built for the crew on the roof, behind the BOP. As the war continued the fort's primary role changed to `.....prevent hostile MTB's or other light craft from entering the Humber.' By November 1943 the crew had been reduced and the 6 pounders placed on care and maintenance. The fort ceased military service in 1945.
Post war the fort was placed in care and maintenance and was
demilitarised in 1956. All military equipment was removed and the
fort was sold to the Humber Conservancy Board in 1964 for £625. (1)
The site was visited by the Fortress Studies Group in 1992 during theHolderness Survey. They found the site to be in good condition but felt that the lack of a clear conservation policy put it at risk. (2)
This feature is visible on air photographs. (3)
The larger of two island forts built between 1915 and 1919 to defend the mouth of the Humber during WW1. It consists of a four-level cylindrical steel structure built on an octagonal concrete base and was originally armed with four 6-inch breech-loading (BL) MKVII guns on coastal-platform (CP) II mountings and four 90cm searchlights housed in steel sponsons. During WW2, in response to the fort¿s new role as a guard against hostile motor torpedo boats entering the Humber, two new reinforced concrete searchlight sponsons were added and the two flanking 6-inch guns were replaced with two twin 6-pounder quick-firing (QF) guns. At the end of the war the fort was placed under care and maintenace and occupied by a small peace-time garrison until demilitarisation in 1956. It was finally sold to the Humber Conservancy Board in November 1964. There are plans to convert the fort to a drug and alcohol detoxification centre. Grade II listed. (4)
Sea Fort. Fort retains all its original features and is in excellent condition. No.1 (6in) gun. [information from 1998 aerial photographs]. In the mouth of the Humber between Humberston and Spurn Head. The fort was not armed in the First World War. In 1919, 4 x 6-inch guns were installed, but two of those were replaced by 2 x 6-pounders in 1942. Disarmed in 1947. (5)
Bull Sand Fort, with its smaller companion fort on Haile Sand (Lincolnshire) 3.75 kilometres to the south-west, guarded the approaches to the Humber with gun batteries and an anti-submarine net of steel mesh stretched between them across the mouth of the estuary. Bull Fort had full amenities, including its own fresh water supply, for a garrison of 200. Armaments, besides the usual small and rapid-fire weapons, consisted of two 6 inch guns and two 6-pounder guns. A reputed 40,000 tons of concrete and steel went into its construction, at a cost of £l,500,000. Both forts were constantly manned during both world wars, and were often under attack from aircraft and submarine. The Army left in 1956, but the forts were still manned until the early 1960s, when both were sold to the Humber Conservancy Board. (6)
Bull Sand Fort located at TA 3704 0923. Bull Sand Fort was constructed by C.J. Willis & Sons from 1915 and opened in 1919. The five-storey fort comprised an octagonal foundation with a circular walls above 25 metres (82 feet) in diameter. The circular walls were construced with concrete faced with steel armour plating, which was 11 inches (0.27m) thick on the seaward side. A further layer of steel plating lined the concrete shell internally. The foundation floor of the fort was used for storage and the 'ground' floor was for men's barracks, workshops and technical services. The first floor was used mostly for domestic purposes, housing further barracks, officers' quarters, kitchens and mess rooms for its over 200 crew members. The top floor held the weapons and above that was the Battery Observation Point and plotting room. The searchlights, of which originally there were four and later six, were positioned from sponsons on the first floor. The fort was rearmed in 1940 and used throughout the Second World War. It was retained for use after the war. (7-8)
Aerial photography from 1998 shows that the fort retains all of its original features and is in excellent condition. (9) |