Coast Defence Chain Home Low Radar Station, Craster

Summary

Second World War Coast Defence Chain Home Low Radar Station, 1941.

Reasons for Designation

Coast Defence Chain Home Low Radar Station, Craster, erected in 1941, is listed at Grade II for the following principal reasons:

Architectural interest:

* a substantially intact radar station that retains its two principal buildings, including the gantry base, which allows a clear understanding of how the site functioned;

* as a good example of the type of small coastal radar station erected in 1941 to detect surface shipping;

* the buildings retain their original plan-forms, legible room functions, and surviving fittings, such as a generator bed to the powerhouse, cable ducting and witness marks to the walls of the TXRX building, and evidence of power transmission;

* the site components reflect the importance of a backup power source in ensuring an uninterrupted radar service during the Second World War.
 
Historic interest:

* a physical manifestation of war time tensions and fears, and the need for a national defence system, which resulted in the construction of a chain of radar stations to protect Britain's coast;

* the Coast Defence Chain Home Low stations provided early warning of German aerial attacks, playing a crucial role in the efence of the country and changing the course of the Second World War.

History

The introduction of the aircraft as an offensive weapon provided the rationale for strategic air defence systems adopted by Britain from the early 1920s. These systems initially involved early warning, based on the visual spotting and tracking of aircraft, but developed through acoustic detection devices to radar. The principles behind radar were widely recognised by the 1930s, but British technicians were the first to translate the science - that an electromagnetic pulse reflected from an object betrays that objects position to a receiver - into a practical means of defence. Following experimental work at Orfordness and Bawdsey Research Station in Suffolk, radar developed through the initial Home Chain, a small group of stations in the extreme south-east of the country, to Chain Home Low (CHL) stations which filled gaps in low-looking cover left by the original technology. A further addition in 1941 was Coast Defence/Chain Home Low (CD/CHL), a low-cover coastal radar designed to detect surface shipping.

Radar stations were designed for raid reporting, passing information to a central operations room which in turn directed fighters to intercept enemy aircraft. This system was to prove vital during the Battle of Britain and radar was constantly evolving and also played a significant role in alerting and deploying night fighters during the Blitz of 1940-41. Range and accuracy improved during the war and aided Fighter Command in their offensive sweeps over occupied Europe from 1943. Many radar stations were reused during the Cold War period for Rotor, a later development of wartime radar.

Documentary research indicates that the radar station at Craster was built in late 1941 as a CD/CHL station, and it continued in operation until July 1944. The site comprised a Transmitter and Receiver (TXRX) block and a stand-by set-house or power-house to provide an emergency power supply for the TR block. Accommodation and service buildings (Nissen huts) were situated on the inland side of the heugh, and wider protection was provided by a series of gun posts, some predating the establishment of the radar site. The perimeter of the compound was defined by a series of barbed wire entanglements. The facility would have been powered by a mains electricity supply, which in this case might have been provided from the village via underground cables. The site was normally operated by one Non-Commissioned Officer, and 12 Other Ranks, in three watches of four men plus, who were Coast Observer Detachments. In addition there were two cooks and nine guards. The station reported plots and observations to the Commander Fixed Defences (CFD) Tyne. Subsequently, accommodation and service blocks were used to house Italian Prisoners of War until 1947. By 1964 the site had been largely cleared leaving only the operational and generator building standing.

Details

Second World War Coast Defence Chain Home Low Radar Station, 1941.

MATERIALS: shuttered reinforced concrete.

PLAN: situated on top of a whinstone escarpment which slopes gently down to the sea from a high point about 150m from the shore. There are two buildings: a rectangular transmit and receive block (TXRX), and set about 25m to the south is an irregular T-shaped stand-by generator.

TRANSMITTER AND RECEIVER BLOCK: situated on the highest point of the escarpment, roughly oriented east-west, standing about 3m high allowing the former aerial array a clear sweep of the coastline.

EXTERIOR: There are four window openings in the south side, one in the east and west sides, and two in the north side; doorways are placed in the west and north sides. The window openings are all of standard size, and have lost their original blast shutters, although shutter brackets are retained to the insides. The east end of the building has a pair of concrete piers to its north and south walls. The metal frames of the former double blast door remain in situ, and a single door to the west entrance and north entrance remains. To all but the north wall there are small regularly-spaced rectangular ventilation openings. A pair of bolts in the east wall are interpreted as fixings for ladder access to the roof; the flat roof slightly extends beyond the external walls and fragments of its bitumous waterproof membrane remain. The top of the roof retains four rectangular metal plates with fixing bolts, that formed the footings for the timber and steel gantry that formerly supported the aerial array. There is evidence of the transmission of power from the room below to the roof, seen in a small, square brick chimney, concrete rendered, encasing a ceramic pipe that would have housed the turning mechanism for this transmission.
INTERIOR: three compartments comprising two small end rooms flanking a larger central plotting room; the west room housed the telephones and the east housed the CHL transmitter. The end rooms are each linked to the plotting room by a doorway that retain the runners of a sliding door. The original interior paintwork remains, brown to the lower walls and cream to the upper walls and ceiling, the latter over a layer of cork chippings for noise reduction and insulation. There are no fixtures and fittings, but the positions of various pieces of equipment are legible through the remains of vertical cable housing within the walls and cable ducting within the concrete floor, and gaps in the interior paintwork forming witness marks. A concrete step up to the east window of the east room suggests this room also functioned as an observation post. The south-west corner of the building cables and wooden battens indicate the point at which the power entered the building. There is various post-war graffiti including a fishing smack of 1940s/50s style.

STAND BY SET HOUSE: an irregular T-shaped building which also stands about 3m high, with a roof that slightly extends beyond the external walls.

EXTERIOR: it has a concrete plinth, and is windowless, but there are vents in the walls of the generator room, four to each long wall and two to the south wall. There are two entrances of different sizes in the north wall allowing for the movement of machinery and the provision of light. Attached to the west wall is a rectangular brick and concrete sump that functioned as a wastewater drain from the water-cooled generator.

INTERIOR: two compartments comprising a south generator room, and an annexe/fuel store attached to the north. The generator room retains an in-situ, concrete generator bed, set slightly off-centre, which has original fixing bolts and a water sump; a sawn-off metal exhaust pipe is embedded in the south wall of the room. An entrance between the generator room and the annexe retains much of the wooden door frame.

This list entry was subject to a Minor Amendment on 1 March 2024 to amend text in the name and description.

Sources

Books and journals
Dobinson, C, Twentieth Century Fortifications in England: Acoustics and Radar (2000),
Dobinson, C, Building Radar: Forging Britain’s Early-Warning Chain, 1935-1945 (2010),

Websites
Craster Northumberland: An Archaeological Investigation of a World War II Radar Station Complex, 2006, Research Department Report Series no 43/2006, accessed 06-07-2023 from https://historicengland.org.uk/research/results/reports/43-2006

Other
National Archives Kew: WO199/78 Protection of CD/CHL Stations: Radar January 1941-January 1942
National Archives Kew: AVIA7/3455 CD/CHL: development of aerials, huts and cabins 1941-1943
National Archives Kew: AVIA7/3535 CD/CHL Stations 1941-1943

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