Anvil Point Lighthouse

File:Anvil point lighthouse durlston dorset.jpg

The lighthouse is built of local stone and was completed in 1881. It was opened by Joseph Chamberlain, the President of the Board of Trade. The lighthouse tower is twelve metres tall, the height of the light above the high-water mark is {{convert|45|m|abbr=on}}. The light is positioned to give a waypoint for vessels passing along the English Channel coast.

Originally the light was illuminated by a Douglass multi-wick mineral oil burner, set within a large (first order) revolving 14-panel dioptric optic by Chance Brothers & Co.{{cite web |title=Lighthouse lantern optics from Anvil Point Lighthouse, 1881. |url=https://www.ssplprints.com/image/86685/lighthouse-lantern-optics-from-anvil-point-lighthouse-1881 |website=Science & society |access-date=7 March 2019 |archive-date=27 March 2019 |archive-url=https://web.archive.org/web/20190327101251/https://www.ssplprints.com/image/86685/lighthouse-lantern-optics-from-anvil-point-lighthouse-1881 |url-status=dead }} It was the first example of a significant new design of lighthouse optic, whereby (through the use of dense flint glass in the upper and lower portions) the height of a Fresnel lens could be significantly increased, dispensing with the need for additional reflective prisms above and below;{{cite book |last1=Chance |first1=James Frederick |title=A History of the Firm of Chance Brothers & Co. |date=2018 |publisher=Society of Glass Manufacturers |location=Sheffield |page=178}} the lenses alone stood {{convert|6|ft|2|in|abbr=on}} high. The lamp was also specially designed for Anvil Point by James Douglass; it was subsequently used in other large coastal lighthouses,{{cite journal |last1=Douglass |first1=William Tregarthen |title=The New Eddystone Lighthouse |journal=Engineering News |date=19 April 1884 |volume=11 |page=184}} a series of international patents having been granted.[https://uslhs.org/sites/default/files/attached-files/290545%20Douglass%20Burner%20for%20gas%20or%20oil%20Patent.pdf US Patent grant 1883.]

An explosive fog signal was established at the lighthouse in February 1894, which in foggy weather sounded once every ten minutes[https://www.thegazette.co.uk/London/issue/26487/page/1091 London Gazette, Issue 26487, Page 1091, 20 February 1894] (later altered to every five minutes).{{cite book |title=British Islands Pilot, vol. 1 |date=1915 |publisher=United States Hydrographic Office |location=Washington DC |page=224}}

In the early 20th century a paraffin vapour burner (PVB) replaced the oil lamp.

File:Anvil Point Lighthouse (3625429605).jpg

During 1960, the lighthouse was modernised and electrified (with a new lamp, powered by mains electricity, replacing the PVB). At the same time a smaller optic replaced the original lens array, which was removed and donated to the Science Museum.{{cite book |last1=Woodman |first1=Richard |last2=Wilson |first2=Jane |title=The Lighthouses of Trinity House |date=2002 |publisher=Thomas Reed |location=Bradford-on-Avon, Wilts. |pages=96–97}} That same year, the five-minute explosive fog signal was replaced by a triple-frequency electric signal, sounded from a stack of thirty tannoy emitters positioned on the seaward edge of the compound directly in front of the lighthouse. In 1981 new automatic equipment was installed, but the fog signal was discontinued in 1988.

Anvil Point Lighthouse was fully automated on 31 May 1991 and is now monitored and controlled from the Trinity House Operations Control Centre at Harwich.{{cite web | url = http://www.trinityhouse.co.uk/events_and_leisure/visitor_centres/anvil_point.html | title = Anvil Point Lighthouse | publisher = Trinity House | access-date = 2011-08-27}}

The lighthouse had a 1,000 watt filament lamp with an intensity of 500,000 Candela. The lights range was about {{convert|19|nmi}}, but was reduced to {{convert|9|nmi}} following a review of aids to navigation in 2010.{{cite web|url=http://www.orfordpiece.com/TH_2010_AtoN_Review_Consultation_Document_1_.pdf |title=Trinity House 2010 Aids to Navigation Review |publisher=Trinity House |url-status=dead |archive-url=https://web.archive.org/web/20150108214138/http://www.orfordpiece.com/TH_2010_AtoN_Review_Consultation_Document_1_.pdf |archive-date=2015-01-08 }}

In 2012, an LED lamp was installed above the rotating Fresnel lens to serve as the main light at Anvil Point; its character is, as it was previously, a white flash every 10 seconds.{{cite web |title=Anvil Point Lighthouse |url=https://www.trinityhouse.co.uk/lighthouses-and-lightvessels/anvil-point-lighthouse |website=Trinity House |access-date=7 March 2019}} (The old lens, though no longer in use, remains in place in the tower.)

{{Portal|England|Engineering}}

• List of lighthouses in England

{{Reflist}}

{{Commons category}}

• [https://www.trinityhouse.co.uk/lighthouses-and-lightvessels?type=lighthouse Trinity House]
• [https://www.diomedia.com/stock-photo-lighthouse-lantern-optics-from-anvil-point-lighthouse-1881-image5524767.html Photograph of the original first-order optic]
• [https://collection.sciencemuseumgroup.org.uk/objects/co5055/gas-burner-assembly-gas-burners Photograph of the Paraffin Vapour Burner]
• [https://www.youtube.com/watch?v=UQlQNt1GmiI 1993 video tour of the lighthouse by P. Halil (former keeper)]

{{Lighthouses of Trinity House}}

{{Authority control}}

Category:1881 establishments in England

Category:Lighthouses completed in 1881

Category:Lighthouse museums in England

Category:Lighthouses in Dorset

Category:Lighthouses of the English Channel

Category:Tourist attractions in Dorset

Category:Towers in Dorset

Category:Swanage

Category:Grade II listed lighthouses

Category:Grade II listed buildings in Dorset