Editing Southwold Lighthouse (section)

== History ==
[[File:Lighthouse blue sky.jpg|thumb|left|upright|Southwold Lighthouse]]
Construction of the lighthouse began in 1887, led by [[James Nicholas Douglass|Sir James Douglass]], Engineer in Chief of [[Trinity House]].<ref name="thsouthwold">[https://www.trinityhouse.co.uk/lighthouses-and-lightvessels/southwold-lighthouse Southwold Lighthouse] {{Webarchive|url=https://web.archive.org/web/20160509190842/https://www.trinityhouse.co.uk/lighthouses-and-lightvessels/southwold-lighthouse |date=9 May 2016 }}, Trinity House. Retrieved 29 October 2012.</ref> A light was lit on a temporary structure in February 1889 and the lighthouse itself began operating on 3 September 1890.<ref name="thsouthwold" /> Previously, three fixed lights had been displayed from the cliff at Southwold; these were now discontinued.<ref name="Gazette1890" /> Both the lantern (the uppermost part of the structure) and the optic (a [[First order Fresnel lens|first-order]] fixed [[Fresnel lens]]), had originally been built by [[Chance Brothers]] in 1868 for [[Happisburgh Lighthouse|Happisburgh Low Lighthouse]]; they became available for re-use when the latter light was demolished in 1883.<ref name="bbcsuffolk">[http://www.bbc.co.uk/suffolk/content/articles/2005/07/02/coast05walks_stage2.shtml Point 2 – The Lighthouse] {{Webarchive|url=https://web.archive.org/web/20071217150749/http://www.bbc.co.uk/suffolk/content/articles/2005/07/02/coast05walks_stage2.shtml |date=17 December 2007 }}, ''[[BBC News]] Suffolk'', 2 July 2005. Retrieved 29 October 2012.</ref>

{{stack|[[File:Lighthouse lens - geograph.org.uk - 514903.jpg|thumb|right|upright|Lower half of the 1868 optic (pictured in 2007)]]}}
The light was initially powered by a six-wick [[Argand lamp|Argand oil burner]];<ref name="pelangi">[http://www.pelangi.co.uk/appnotes/32064-Southwold%20PRL400.pdf Application note 32064 – Southwold Conversion] {{Webarchive|url=https://web.archive.org/web/20140221215857/http://www.pelangi.co.uk/appnotes/32064-Southwold%20PRL400.pdf |date=21 February 2014 }}, Pelangi. Retrieved 4 January 2013.</ref> it displayed a [[Occulting Light|group occulting]] characteristic (the light being eclipsed twice every 20 seconds)<ref name="SMuseum">{{cite web |title=The Sea - Southwold's Lighthouse |url=https://www.southwoldmuseum.org/thesea_lighthouse.htm |website=Southwold Museum |accessdate=21 January 2020 |archive-date=22 June 2020 |archive-url=https://web.archive.org/web/20200622180833/http://www.southwoldmuseum.org/thesea_lighthouse.htm |url-status=live }}</ref> and had a visible range of {{convert|17|nmi}}.<ref name=Gazette1890>{{Cite web |url=https://www.thegazette.co.uk/London/issue/26090/page/5098 |title=London Gazette, Issue 26090, Page 5098, 23 September 1890 |access-date=25 February 2020 |archive-date=25 February 2020 |archive-url=https://web.archive.org/web/20200225101817/https://www.thegazette.co.uk/London/issue/26090/page/5098 |url-status=live }}</ref> The light was white, but shone red across defined [[Sector light|sectors]] to the north and to the south (indicating the Barnard sands and Sizewell Bank respectively); in addition, 'spare' light, which would otherwise have shone needlessly westwards, was diverted by way of vertical [[Collimator|condensing prisms]] so as to intensify these red sectors.<ref name="pelangi" />

Just six days after the light was commissioned there was a fire in the lighthouse with the burner being destroyed.<ref name="bbcsouthwold">[http://www.bbc.co.uk/suffolk/content/articles/2005/07/04/coast05walks_peter_austin_feature.shtml Discovering Southwold] {{Webarchive|url=https://web.archive.org/web/20181220100634/http://www.bbc.co.uk/suffolk/content/articles/2005/07/04/coast05walks_peter_austin_feature.shtml |date=20 December 2018 }}, ''[[BBC News]] Suffolk'', 4 July 2005. Retrieved 29 October 2012.</ref><ref name="museum">[http://www.southwoldmuseum.org/thesea_lighthouse.htm The sea – Southwold's Lighthouse] {{Webarchive|url=https://web.archive.org/web/20120614133513/http://www.southwoldmuseum.org/thesea_lighthouse.htm |date=14 June 2012 }}, Southwold Museum. Retrieved 29 October 2012.</ref> The inexperience of the new lighthouse keepers was blamed for the fire.<ref name="museum" />

The burner was replaced with an oil-fired light in 1906 and a petroleum burner in 1923. The light was electrified and automated in 1938,<ref name="thsouthwold" /> at which time the [[light characteristic]] was changed to group flashing, 6 flashes every 20 seconds (modified to 4 flashes in 1965).<ref name="SMuseum" /> It was converted to battery operation, with the batteries charged using mains electricity, in 2001.<ref name="bbcsuffolk" /> Until 2013 a cluster of three 90-watt [[Osram]] Halostar lamps provided the main light within the optic (which had a range of {{convert|17|nmi|km mi}}).

The lighthouse, along with [[Lowestoft Lighthouse]] to the north, was threatened with closure by Trinity House in 2005, with shipping companies increasingly using [[satellite navigation systems]] rather than relying on lighthouses.<ref name="bbc04aug05">[http://news.bbc.co.uk/1/hi/england/suffolk/4747201.stm Landmark lighthouses may be axed] {{Webarchive|url=https://web.archive.org/web/20230813215845/http://news.bbc.co.uk/1/hi/england/suffolk/4747201.stm |date=13 August 2023 }}, ''[[BBC News]]'', 4 August 2005. Retrieved 29 October 2012.</ref><ref name="eadt04aug05">Barnes, Jonathan. (4 August 2005). [http://www.eadt.co.uk/news/historic_lighthouses_face_closure_1_72557?ot=archant.PrintFriendlyPageLayout.ot Historic lighthouses face closure] {{Webarchive|url=https://web.archive.org/web/20160304074356/http://www.eadt.co.uk/news/historic_lighthouses_face_closure_1_72557?ot=archant.PrintFriendlyPageLayout.ot |date=4 March 2016 }}, ''[[East Anglian Daily Times]]'', Retrieved 29 October 2012.</ref> Both lighthouses were reprieved in 2009 following a review by Trinity House that found that satellite navigation systems were not yet sufficiently reliable.<ref name="torygraph12jan09">[https://www.telegraph.co.uk/news/uknews/4223087/Lighthouse-wins-reprieve-as-sat-nav-for-ships-not-reliable-enough.html Lighthouse wins reprieve as sat nav for ships not reliable enough] {{Webarchive|url=https://web.archive.org/web/20171009063645/http://www.telegraph.co.uk/news/uknews/4223087/Lighthouse-wins-reprieve-as-sat-nav-for-ships-not-reliable-enough.html |date=9 October 2017 }}, ''[[The Daily Telegraph]]'', 9 January 2009. Retrieved 29 October 2012.</ref>

[[File:Lighthouse, Southwold 13-09-2014 (19369482922).jpg|thumb|left|upright|2014: Central and lower parts of the old optic retained for emergency use; above it, the new main lamp inside a small rotating optic.]]
Then in December 2012, the range of Southwold's light was increased to {{convert|24|nmi|km mi}}, to compensate for the imminent closure of [[Orfordness Lighthouse]] (which took place in June 2013).<ref name="thsouthwold" /><ref name="bbcsuffolk" /><ref name="pelangi" /><ref name="lowjournal12may11">Rogers, Lauren (12 May 2011) [http://www.lowestoftjournal.co.uk/news/southwold_lighthouse_reach_will_be_extended_to_keep_mariners_safe_1_891007 Southwold Lighthouse reach will be extended to keep mariners safe] {{Webarchive|url=https://web.archive.org/web/20160313083739/http://www.lowestoftjournal.co.uk/news/southwold_lighthouse_reach_will_be_extended_to_keep_mariners_safe_1_891007 |date=13 March 2016 }}, ''Lowestoft Journal''. Retrieved 29 October 2012.</ref><ref name="bbc18aug11">[https://www.bbc.co.uk/news/uk-england-suffolk-14574721 Orfordness Lighthouse: last chance for the public to visit?] {{Webarchive|url=https://web.archive.org/web/20181026213503/https://www.bbc.co.uk/news/uk-england-suffolk-14574721 |date=26 October 2018 }}, ''[[BBC News]] Suffolk'', 18 August 2011. Retrieved 29 October 2012.</ref><ref name="th03aug12">[http://www.trinityhouse.co.uk/mariner_info/notice_to_mariners/b/03082012_1.html Notice to mariners 38/2012 B5 Southwold LH] {{Webarchive|url=https://web.archive.org/web/20121222110631/http://www.trinityhouse.co.uk/mariner_info/notice_to_mariners/b/03082012_1.html |date=22 December 2012 }}, Trinity House, 3 August 2012. Retrieved 29 October 2012.</ref><ref name="bbc28jun13">[https://www.bbc.co.uk/news/uk-england-suffolk-23091214 Orfordness Lighthouse gets switched-off and left to the sea] {{Webarchive|url=https://web.archive.org/web/20181110113013/https://www.bbc.co.uk/news/uk-england-suffolk-23091214 |date=10 November 2018 }}, BBC Suffolk news website, 28 June 2013. Retrieved 28 June 2013.</ref> This was achieved by installing a new main light: a BLV Topspot 90 Volt Metal Halide 150-watt lamp placed within a small revolving optic.<ref name="thsouthwold" /><ref name="pelangi" /> To make space for it within the lantern room the upper prismatic section of the old optic was removed (one section was put on display at the foot of the tower, another was loaned to [[Happisburgh Lighthouse]] where it has been put on display not far from its original location).<ref>{{cite web |title=1 March 2019 [photo] |url=https://www.flickr.com/photos/ian-s/27922202775 |website=uklighthousetour |date=18 June 2016 |accessdate=27 March 2019}}</ref> The central and lower sections of the old lens, together with its lamp, have been retained for use as an emergency backup.<ref name="thsouthwold" />