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Trevose Head Lighthouse
Trevose Head, Cornwall
associated engineer
Thomas and Jacob Olver
date  1st December 1847
era  Victorian  |  category  Lighthouse  |  reference  SW850766
Trevose Head Lighthouse is built on the north west extremity of Trevose Head on the north Cornish coast. Its white tower rises above the dramatic sheer grey granite cliffs that are more than 45m above the level of the sea.
A structure was proposed in the area in 1809, as a guide for shipping using the Bristol Channel, because the only nearby lights at the time were the Longships and Lundy lighthouses. The lighthouse organisation Trinity House considered the matter in 1813 and 1832, and eventually a lighthouse was constructed for it in 1847 by Thomas and Jacob Olver of Falmouth.
The light in use today is one of a pair originally constructed here — a higher light and a lower. Pairs of fixed lights helped ships get their positions more accurately. It is the 27m tall higher light that remains in use — a white-painted cylindrical stone tower with gallery. Nearby are dwellings for keepers. Operations began on 1st December 1847, with a crew of two men.
The two original lights were oil lamps, backed with reflectors. The higher light was in the same position as the present lantern — 62m above high water level. It was visible for 31km. The lower light was 15m to seaward of the higher one, 39m above high water level and visible for 26km.
After refurbishment work in 1882, use of the lower light was discontinued and the higher light was replaced with a single occulting white lamp. There were three keepers at this time.
Further work was undertaken in 1911 and 1912 to modernise the keepersí houses and construct a fog signal house — surprisingly, the lighthouse had no fog signal at the very beginning, considering how much this coast is affected by sea mist. In August 1912, the lantern was changed to a flashing red light using a 920mm first order catadioptric lens with three symmetrical panels.
In February 1913, a new fog signal came on line. It was developed by Lord Rayleigh, scientific adviser to Trinity House. Shaped like a rectangular trumpet 11m long, with an aperture 5.5m wide by 0.6m high, it was designed to give a wide horizontal spread of sound.
Sometime around 1920, a Hood high power vaporised oil burner with autoform mantel was installed in the lantern, which produced a red flash of 0.3 seconds duration and 194,200 candela intensity, once every 5 seconds. This increased the light's visible range to a nominal 40km. The motive power for the 3.7 tonne lens came from a clockwork motor driven by weights.
In 1963, the Rayleigh fog signal was replaced with a Supertyphon signal with eight horns. In 1974, the lighthouse was converted to electric power. The lantern now flashed red every 5 seconds and had a range of 40km.
Automation came in 1995 and the crew left at the end of that year. Telemetry was installed to enable remote control. The existing lantern (1912) has been kept, although the rotational speed has been slowed down. The light now shines white and the lamp has been changed to 35W halide in a two-position lamp changer. This has an intensity of 89,900 candela and a range of 37km. The lighting and extinguishing of the lamp is controlled by a photocell attached to the lantern murette. A new emergency light has been mounted on the gallery handrail and it has a range of 19km.
A new electric omni-directional fog signal controlled by a fog detector was installed to replace the old air fog signal. When operating, it gives two blasts every 30 seconds.
The lighthouse is open to the public on weekdays.
research: ECPK
bibliography
www.trinityhouse.co.uk
www.unc.edu
Location

Trevose Head Lighthouse