Portland Bill Lighthouse
|Portland Bill Lighthouse|
|Place:||England , Weymouth|
|Location:||On the southern tip of the Isle of Portland|
|Fire carrier height :||41 m|
|Fire height :||43 m|
|Identifier :||Fl (4) W.20s|
|Scope knows:||24.3 nm (45 km )|
|Optics:||4 diaphragms with catadioptric lenses|
|Function:||Orientation and warning lights|
|Operating time:||since 1906|
The Portland Bill Lighthouse is a lighthouse in England on the Isle of Portland in the English Channel . The lighthouse guides the ships around the southeast upstream sandbanks Bill and Shambles through the fairway dominated by strong tidal currents into the port of Weymouth . It is also a landmark for ships in the English Channel. It is operated and maintained by Trinity House Lighthouse Service , the official English authority responsible for the maintenance of lighthouses and other navigation signs. It is comparable to the Waterways and Shipping Office in Germany .
In the early eighteenth century, some shipowners and the City of Weymouth petitioned Trinity House to build a lighthouse to facilitate navigation around the Isle of Portland. Trinity House , however, considered a tower at this point to be unnecessary and refused to build it. Further efforts finally resulted in an order from May 26, 1716 from George I to build a tower at Trinity House. They awarded the contract to a private consortium for 61 years, which built two towers (upper and lower tower). These towers were lit with coal fires. At the end of 61 years, the business went back to Trinity House. In 1789 one of the two towers was demolished and replaced by a new one, which with its greater range could guide ships in the English Channel and into the port of Weymouth by day and night. An Argand lamp developed by Aimé Argand was installed in this tower . The Portland Bill lighthouse was the first in England to be equipped with this technology.
In 1798 two guns were installed on the lighthouse to fend off the possible invasion of Napoleon . In 1869 the two old towers were replaced by new buildings. The current tower was built in 1906 to replace these two. The old towers are still preserved, one is currently used as a bird observatory. The new tower has been automated since 1996 and is monitored by the Trinity House Control Center in Harwich . A visitor center open in summer is housed in the tower. During this time it is also possible to climb the tower.
The tower has a height of 41 meters, the light is at a height of 43 meters above sea level. The optics used on the lighthouse are very unusual due to their arrangement. It creates a light that is visible four times every 20 seconds. It changes step by step from one to four flashes between 221 and 224 degrees and from four to one flash between 117 and 141 degrees. The light intensity is 635,000 candela , the range is around 45 km. In foggy conditions, a compressor-operated fog horn warns the shipping company every 30 seconds for 3.5 seconds.