Portland Bill Lighthouse

File:Portland Bill Lighthouse, dawn 6.19 am.jpg in the distance]]

The two original lighthouses, now known as the Old Higher Lighthouse and Old Lower Lighthouse, operated as a pair of leading lights to guide ships between Portland Race and The Shambles sandbank. They were constructed in 1716, both rebuilt in 1869, and decommissioned following the completion of the present lighthouse.{{cite web|url=http://www.dorsetlife.co.uk/2014/03/portland-three-lighthouses-walk/|title=Portland – Three Lighthouses Walk|work=dorsetlife.co.uk|access-date=14 June 2015}} At the turn of the 20th-century, Trinity House put forward plans for building a new lighthouse at Bill Point. They acquired the required land in 1903.{{cite web|url=http://freepages.genealogy.rootsweb.ancestry.com/~pbtyc/Portland/PYB/Chronology.html|title=Portland Year Book|work=ancestry.com|access-date=14 June 2015}}{{cite book|last=Legg|first=Rodney|title=Portland Encyclopaedia|year=1999|publisher=Dorset Publishing Company|isbn=978-0948699566|page=85}}

The builders, Wakeham Bros. of Plymouth, began work on the foundations in October 1903.{{cite web|url=http://freepages.genealogy.rootsweb.ancestry.com/~pbtyc/Portland/PYB/Lighthouse.html|title=Portland Year Book|work=ancestry.com|access-date=14 June 2015}} Chance & Co of Birmingham supplied and fitted the lantern.{{Cite web |url=http://www.theoutdoorstore.co.uk/blog/wp-content/uploads/2010/08/route3-portlandbill.pdf |title=Archived copy |access-date=14 June 2015 |archive-url=https://web.archive.org/web/20150929172034/http://www.theoutdoorstore.co.uk/blog/wp-content/uploads/2010/08/route3-portlandbill.pdf |archive-date=29 September 2015 |url-status=dead |df=dmy-all }} A pressurised vapour paraffin lamp was used, placed at the centre of a large (first-order) revolving optic; weighing 3.5 tons, this was made up of four asymmetrical catadioptric lens panels and a concave prismatic reflector.{{cite book |last1=Renton |first1=Alan |title=Lost Sounds: The Story of Coast Fog Signals |date=2001 |publisher=Whittles |location=Caithness, Scotland}} The lighthouse was completed in 1905 at a cost of £13,000, and the lamp first lit on 11 January 1906. A red sector light was provided in addition to the main light, shining from a window in the lower part of the tower, to indicate the position of The Shambles. The light was electrified in the mid-1950s.{{cite journal |title=General Lighthouse Fund |journal=Parliamentary Papers |date=1957 |volume=20 |page=16}}

{{Stack|File:Portland Bill Lighthouse (36717563126).jpg}}

In 1940 the lighthouse was provided with an F-type diaphone fog signal, sounding from a window part-way up the tower. Compressed air was provided to six cylindrical storage tanks by a pair of Reavell compressors, all located (together with a standby generator) within the base of the tower. These were connected at a higher level to the sounding tanks, which fed the compressed air to the diaphone itself, mounted behind its trumpet-like emitter which protruded through the window. Admission of air into the diaphone was controlled by a clockwork (later electric) coder, which caused the diaphone to sound a 3.5-second blast every 30 seconds. The 180 Hz note had an audible range of {{convert|7|nmi|abbr=on}} (which could be doubled under favourable conditions). The diaphone remained in regular use as an aid to navigation until 1995, when it was replaced by a high-frequency electric fog signal (sounding from another window, further down) in readiness for automation.

On 18 March 1996, Portland Bill Lighthouse was demanned, and all monitoring and control transferred to the Trinity House Operations & Planning Centre in Harwich.{{cite web|url=http://www.trinityhouse.co.uk/lighthouses/lighthouse_list/portland_bill.html|title=Portland Bill|work=trinityhouse.co.uk|access-date=14 June 2015|url-status=dead|archive-url=https://web.archive.org/web/20150627123852/http://www.trinityhouse.co.uk/lighthouses/lighthouse_list/portland_bill.html|archive-date=27 June 2015|df=dmy-all}} The original Type F diaphone was decommissioned in 1996, but in 2003 Trinity House restored it to occasional use for the benefit of visitors;{{cite web|url=http://www.bournemouthecho.co.uk/archive/2003/08/27/Dorset+Archive/5376521.Blast_from_the_past/ |title=Blast from the past (From Bournemouth Echo) |publisher=Bournemouthecho.co.uk |date=27 August 2003 |access-date=24 November 2012}} (it was sounded regularly for half an hour on Sunday mornings, except when foggy, until 2017).{{cite web |title=Portland Bill Lighthouse |url=https://www.portlandhistory.co.uk/portland-bill-lighthouse.html |website=The Encyclopaedia of Portland History |access-date=22 July 2019}}

In the early 21st century the lighthouse used a 1 kW MBI lamp together with the same rotating lens system that had been in use since 1906. (It flashed four times every 20 seconds with an intensity of 635,000 candelas and a range of 25 nautical miles.) The fog signal was used in times of bad weather; it gave a four-second blast every 30 seconds with a range of 2 nautical miles.

In November 2018 Trinity House applied for (and obtained) planning permission to remove the lamp and optic from the lantern room as part of a programme of modernisation.{{cite web |title=Planning – Application Summary |url=https://planning.dorset.gov.uk/public-access/applicationDetails.do?activeTab=summary&keyVal=DCAPR_29321 |website=dorsetforyou |publisher=Dorset Council |access-date=23 March 2019 }}{{Dead link|date=August 2023 |bot=InternetArchiveBot |fix-attempted=yes }} It proposed relocating the lens array to the base of the tower,{{cite web |title=The modernisation planned for Portland Bill lighthouse |url=https://www.dorsetecho.co.uk/news/17205006.the-modernisation-planned-for-portland-bill-lighthouse/ |website=Dorset Echo |date=7 November 2018 |access-date=12 March 2019}} which led to the removal of the historic diaphone fog-signalling equipment, installed there in 1940 and still in working order, on the basis that this was 'the only available [space] for retaining the historic optic on-site'.

In 2019-2020 a new non-rotating LED light source was installed in the lantern room{{cite web |title=Heritage Statement / Assessment: Portland Bill Lighthouse Modernisation |url=https://planning.dorset.gov.uk/public-access/files/03DF54F66E53DEAF5E8CAB6E3760DDBA/pdf/WP_18_00831_LBC--1974104.pdf |website=dorsetforyou |publisher=Trinity House |access-date=23 March 2019 }}{{Dead link|date=August 2023 |bot=InternetArchiveBot |fix-attempted=yes }} and a new omnidirectional fog signal was installed on the exterior lantern gallery (replacing the electric emitter installed in the 1990s).{{cite web |title=Portland Bill Lighthouse Modernisation – DAS & Methodology |url=https://planning.dorset.gov.uk/public-access/files/D1F85BC50A49A70873A636B70B6E36E5/pdf/WP_18_00831_LBC--1980500.pdf |website=dorsetforyou |publisher=Trinity House |access-date=23 March 2019 }}{{Dead link|date=August 2023 |bot=InternetArchiveBot |fix-attempted=yes }} The two LED lanterns (one of which is used, the other kept on standby) have a reduced range of {{convert|18|nmi}}.{{cite web |title=Portland Bill Lighthouse visitor centre |url=https://www.trinityhouse.co.uk/lighthouse-visitor-centres/portland-bill-lighthouse-visitor-centre |website=Trinity House |access-date=21 January 2021}}

As Portland's prime attraction, the Portland Bill Lighthouse is open to the public for tours. A visitor centre is housed in the former lighthouse keeper's quarters. The original centre closed in 2013 due to lack of funding,{{cite web|url=http://www.dorsetecho.co.uk/news/10868078.Tourism_Information_Centre_shuts_at_Portland_Bill_lighthouse/|title=Tourism Information Centre shuts at Portland Bill lighthouse|work=Dorset Echo|date=11 December 2013 |access-date=14 June 2015}} however a new renovated centre opened in 2015.{{cite web |url=http://www.trinityhouse.co.uk/lighthouses/lighthouse_list/portland_bill.html?tab=visitor |title=Portland Bill Lighthouse Visitors Centre |access-date=2012-11-24 |url-status=dead |archive-url=https://web.archive.org/web/20120822043730/http://www.trinityhouse.co.uk/lighthouses/lighthouse_list/portland_bill.html?tab=visitor |archive-date=22 August 2012 |df=dmy-all }} The tours operated at the lighthouse last approximately 45 minutes and visitors are able to climb the 153 steps to the top of the lighthouse.{{cite web |url=http://www.resort-guide.co.uk/infoloca.php3?locacode=11160&servcode=1149&service=attr |title=Portland Bill Lighthouse Visitor Centre was just one of many places to visit in Portland Bill Lighthouse Visitor Centre |publisher=Resort-guide.co.uk |access-date=24 November 2012 |archive-url=https://web.archive.org/web/20140502001812/http://www.resort-guide.co.uk/infoloca.php3?locacode=11160&servcode=1149&service=attr |archive-date=2 May 2014 |url-status=dead |df=dmy-all }}

File:Portland Bill and Trinity House Obelisk.jpg|The lighthouse and the surrounding ex-quarried area.

File:Bulbs In Portland Lighthouse BY ROBERT KILPIN.jpg|Lamps in Portland Bill Lighthouse

File:Trinity House Flag on Portland Bill Lighthouse.JPG|Trinity House flag on Portland Bill Lighthouse, Dorset

File:Foghorn on Portland Bill Lighthouse, Dorset.jpg|The diaphone foghorn emitter of Portland Bill Lighthouse

File:Bill of Portland- the lighthouse lens (geograph 3643681).jpg|Fresnel lenses and prismatic mirror

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