Location | Nab Rocks, near the Isle of Wight, England |
---|---|
Coordinates | 50°40′03″N0°57′04″W / 50.66749733°N 0.951162862°W [1] |
Tower | |
Constructed | 1918 towed into position 1920 |
Construction | Steel and concrete |
Automated | 1983 |
Height | 17 m (56 ft) [2] |
Shape | Broad cylindrical tower faced with reinforced concrete |
Markings | Unpainted tower, white light |
Operator | Trinity House [3] |
Fog signal | 1 blast every 30s. (range 2 nmi (3.7 km)) |
Racon | T |
Light | |
First lit | 1920 |
Focal height | 17 m (56 ft) |
Light source | Vega LED lantern |
Intensity | 2,850 candela [2] |
Range | 12 nmi (22 km) |
Characteristic | Fl W 10s. |
The Nab Tower is a tower originally planned for anti-submarine protection in the English Channel in World War I. It was sunk over the Nab rocks east of the Isle of Wight to replace a lightship after the war, and is a well-known landmark for sailors as it marks the deep-water eastern entry into the Solent.
During the First World War, the British Admiralty designed eight towers codenamed M-N that were to be built and positioned in the Straits of Dover to protect allied merchant shipping from German U-boats. Designed by civilian Guy Maunsell, the towers were to be linked together with steel nets and armed with two 4-inch guns with the idea of closing the English Channel to enemy ships.
However, by the end of the war in 1918 only one such tower had been completed, at the then-cost of one million pounds, and was located at Shoreham Harbour, awaiting deployment. While another part-built tower would eventually be dismantled in 1924, there remained the completed 92-foot-tall (28 m) metal cylinder sitting on a raft of concrete.
In 1920 the completed tower was towed by two paddle-wheel tugs to the Nab rock, a rock in the deep-water approach to the eastern Solent and previously marked by a lightship. [4] Buoyancy was provided by the honeycomb construction of the concrete base, creating 18 watertight compartments. When these were flooded, the structure sank and settled to rest at an angle of 3 degrees from vertical towards the northeast – a characteristic tilt which is obvious to this day. [5]
Initially, the tower had a single centrally-placed lamp containing an Osram gas-filled incandescent light bulb, which gave a single white flash every ten seconds, with a visible range of 16 nautical miles. [6] A fog horn was also installed, in a separate shed on the tower top. Later, the single light was replaced by a pair of small (fifth-order) revolving dioptric optics, each of which produced a single flash every 10 seconds; [7] they were mounted in small turrets on opposite sides of the tower: one shone red towards the north-west, the other shone white towards the south-east (their arcs overlapped, so that vessels approaching from seaward would see the red light as well as the white if their course took them too close to St Catherine's Point, approaching from the west, or Selsey Bill, approaching from the east). [8] In December 1935 a radio beacon was added. [9]
In 1938 a more powerful diaphone fog signal was installed (in place of the old fog horn), which gave one 2.5-second blast every minute. [10] It was synchronised with the radio beacon; by timing the delay between receiving the radio signal and the audible signal, vessels were able to calculate their distance from the tower. [11] The tower was equipped with a fog bell, as well as the diaphone, [12] which sounded one stroke every 7.5 seconds. [10]
The Nab Tower was manned as a lighthouse, but also functioned as a Royal Navy signal station; [5] and during World War II it was equipped with a pair of Bofors guns to provide some defence to the Solent approach, and actually shot down several aircraft. [5] The Royal Navy withdrew its personnel from the tower some time after the war, but the tower remained under Ministry of Defence ownership until 1984, when Trinity House acquired the freehold (they had previously taken over responsibility for the light itself from the Admiralty in 1929). [13] [14]
The Nab Tower still functions as a lighthouse, but since 1983 it has been unmanned. That year, a helicopter pad was constructed on the tower and a new pre-fabricated lantern-tower was installed containing an automated acetylene lamp; [5] as well as powering the lamp, acetylene gas drove the revolving mechanism for the lightweight GRP optic in which the lamp was set. [15] In 1995 the light was converted to solar power operation and a new Orga rotating beacon was installed in the lantern (later a Vega VRB-25 rotating beacon was used). [16]
In November 1999, the merchant freighter Dole America, carrying a cargo of bananas and pineapples, hit the Nab. The ship was badly damaged and only avoided sinking by being run aground. The base of the tower suffered superficial and internal damage. The damage was repaired in 2001.
The tower was featured as the main setting of the 1951 Hammer thriller The Dark Light .
In 2013, Trinity House commissioned BAM Nuttall to undertake a major refurbishment programme due to extensive corrosion of the upper levels, meaning it was unsafe to land helicopters upon the helipad. Partial dismantling of the structure followed, undertaken with the help of a tower crane, which was installed within a former ammunition shaft. [17] The height of the tower was reduced from 27 metres to 17, all external steel and cladding were removed and the existing concrete sub-structure was coated in a new layer of gun-applied concrete. On completion, new AIS and RACON beacons were fitted, along with a fixed main LED light (and identical standby light) with a 12 nautical mile range; [18] a new fog signal was also installed, sounding two blasts every 30 seconds (altered to one blast in 2022). [19] All are solar powered.
The distinctive red lantern structure, removed as part of the refurbishment, is now on display at Hurst Castle, [20] together with the old rotating beacon. [21] In addition, a pair of rotating 4th-order dioptric optics, which were in use on the tower prior to automation, are also displayed at the castle. [22]
Longships Lighthouse is an active 19th-century lighthouse about 1.25 mi (2.0 km) off the coast of Land's End in Cornwall, England. It is the second lighthouse to be built on Carn Bras, the highest of the Longships islets which rises 39 feet (12 m) above high water level. In 1988 the lighthouse was automated, and the keepers withdrawn. It is now remotely monitored from the Trinity House Operations & Planning Centre in Harwich, Essex.
Pendeen Lighthouse, also known as Pendeen Watch is an active aid to navigation located 2 kilometres (1.2 mi) to the north of Pendeen in west Cornwall, England. It is located within the Aire Point to Carrick Du SSSI, the Cornwall Area of Outstanding Natural Beauty and the Penwith Heritage Coast. The South West Coast Path passes to the south.
The Baily Lighthouse is a lighthouse on the southeastern part of Howth Head in County Dublin, Ireland. It is maintained by the Commissioners of Irish Lights.
Royal Sovereign lighthouse is a decommissioned lighthouse marking the Royal Sovereign shoal, a sandbank 11 km (6.8 mi) offshore from Eastbourne. The structure's distinctive shape is easily recognised as the lighthouse tower is perched above a large platform supported by a single pillar rising out of the water. Originally, the platform was manned by three full-time keepers, accommodation being contained in the 'cabin section' immediately below the platform. Additional accommodation was provided for up to four visiting maintenance workers.
South Foreland Lighthouses are a pair of Victorian lighthouses on the South Foreland in St. Margaret's Bay, Dover, Kent, England, used to warn ships approaching the nearby Goodwin Sands. There has been a pair of lighthouses at South Foreland since at least the 1630s. Even after the decommissioning of the Lower Lighthouse the pair continued to be used as leading marks, with Admiralty charts into the 20th century indicating that the 'Lighthouses in line lead south of the Goodwin Sands'.
Start Point lighthouse was built in 1836 to protect shipping off Start Point, Devon, England. Open to the public in summer months, it is owned and operated by Trinity House. It has been designated by English Heritage as a grade II listed building.
Portland Bill Lighthouse is a functioning lighthouse at Portland Bill, on the Isle of Portland, Dorset, England. The lighthouse and its boundary walls are Grade II Listed.
St Bees Lighthouse is a lighthouse located on St Bees Head near the village of St Bees in Cumbria, England. The cliff-top light is the highest in England at 102 m (335 ft) above sea level.
Bull Point Lighthouse is a lighthouse on Bull Point, about one mile (1.6 km) north of the village of Mortehoe, on the northern coast of Devon, England. The lighthouse provides a visual aid to the villages of Mortehoe, Woolacombe and Ilfracombe, and warns of the inhospitable and rocky coast that lines the area.
Hurst Point Lighthouse is located at Hurst Point in the English county of Hampshire, and guides vessels through the western approaches to the Solent.
Wolf Rock Lighthouse is on the Wolf Rock, a single rock located 18 nautical miles east of St Mary's, Isles of Scilly and 8 nautical miles southwest of Land's End, in Cornwall, England, United Kingdom. The fissures in the rock are said to produce a howling sound in gales, hence the name.
Hartland Point Lighthouse is a Grade II listed building at Hartland Point, Devon, England. The point marks the western limit of the Bristol Channel with the Atlantic Ocean continuing to the west. Trinity House, the lighthouse authority for England and Wales, have a lighthouse on the tip of the peninsula.
The Needles Lighthouse is an active 19th century lighthouse on the outermost of the chalk rocks at The Needles on the Isle of Wight in the United Kingdom, near sea level. Designed by James Walker, for Trinity House at a cost of £20,000. It was completed in 1859 from granite blocks, stands 33.25 metres (109.1 ft) high and is a circular tower with straight sides. It replaced an earlier light tower on top of a cliff overhanging Scratchell's Bay, which was first lit on 29 September 1786.
Lowestoft Lighthouse is a lighthouse operated by Trinity House located to the north of the centre of Lowestoft in the English county of Suffolk. It stands on the North Sea coast close to Ness Point, the most easterly point in the United Kingdom. It acts as a warning light for shipping passing along the east coast and is the most easterly lighthouse in the UK.
St Catherine's Lighthouse is a lighthouse located at St Catherine's Point at the southern tip of the Isle of Wight. It is one of the oldest lighthouse locations in Great Britain.
Flamborough Head Lighthouse is an active lighthouse located at Flamborough, East Riding of Yorkshire. England. Flamborough Head Lighthouse acts as a waypoint for passing deep sea vessels and coastal traffic, and marks Flamborough Head for vessels heading towards Scarborough and Bridlington.
Dungeness Lighthouse on the Dungeness Headland started operation on 20 November 1961. Its construction was prompted by the building of Dungeness nuclear power station, which obscured the light of its predecessor which, though decommissioned, remains standing. The new lighthouse is constructed of precast concrete rings; its pattern of black and white bands is impregnated into the concrete. It remains in use today, monitored and controlled from the Trinity House Operations and Planning Centre at Harwich, Essex.
Casquets Lighthouse is an active lighthouse located on the rocky Les Casquets, Alderney, Channel Islands.
The isle of Lundy has three lighthouses: a pair of active lights built in 1897 and an older lighthouse dating from 1797.