Bishop Rock

The Bishop Rock ( kw, Men Epskop) is a skerry off the British coast in the northern Atlantic Ocean known for its lighthouse.
It is in the westernmost part of the Isles of Scilly, an archipelago off the southwestern tip of the Cornish peninsula of Great Britain. The ''Guinness Book of Records'' lists it as the world's smallest island with a building on it.

The original iron lighthouse was begun in 1847 but was washed away before it could be completed. The present building was completed in 1858 and was first lit on 1September that year. Before the installation of the helipad, visitors to the lighthouse would rappel from the top (with winches installed at the lamp level and at the base below) to boats waiting away from the lighthouse.

Bishop Rock is also at the eastern end of the North Atlantic shipping route used by ocean liners in the first half of the 20th century; the western end being the entrance to Lower New York Bay. This was the route that ocean liners took when competing for the Transatlantic speed record, known as the Blue Riband.

History

In the late 13th century, when the Isles of Scilly were under the jurisdiction of John de Allet and his wife Isabella, anyone convicted of felony "ought to be taken to a certain rock in the sea, with two barley loaves and a pitcher of water and left until the sea swallowed him up". The rock was originally recorded as ''Maen Escop'' in 1284 and ''Maenenescop'' in 1302. In Cornish, ''Men Eskop'' means "Bishop's Stone", whilst ''Men an Eskop'' means "the Stone of the Bishop". The outer rocks to the west of St Agnes also used to be known as the Bishop and Clerk, but exactly how they acquired these similar names is not known for certain. A possible explanation is that the shape of the rock is similar to a bishop's mitre.

East of Bishop Rock are the Western Rocks and the Gilstone Reef, where Admiral Shovell's flagship HMS ''Association'' was wrecked in the great naval disaster of 1707. Shovell's remains were repatriated to England by order of Queen Anne shortly after their initial burial in the Isles of Scilly.

The earliest recorded wreck on the rock itself was in 1839, when the brig ''Theodorick'' struck in rough misty weather on 4September. She was out of Mogodore for London carrying a general cargo. In the early hours of , the 600-tonne paddle steamer ''Brigand'', a packet boat, which was en route from Liverpool to St Petersburg, struck the rock with such force that it stove in two large bow plates. The rocks then acted as a pivot, and she swung round and heeled into the rock port side, crushing the paddle-wheel and box to such an extent that it penetrated the engine room. She drifted over seven miles in two hours, before sinking in 90m. All the crew were saved. In 1901 a barque named ''Falkland'' struck the rock, her main yard hitting the lighthouse itself.

Lighthouse

An 1818 report by the Surveyor-General of the Duchy of Cornwall on the dangers to shipping in Cornwall proposed that a lighthouse be built, similar to the Eddystone Lighthouse, upon Bishop Rock, given its location as the westernmost rock of the Isles of Scilly. The plan was considered by the government and building was expected soon, as the engineer John Rennie the Elder made an offer to build it. The government did not take up the offer; but Trinity House surveyed Bishop Rock in 1843 with a view to building a lighthouse, and under their Engineer-in-chief, James Walker, construction work began in 1847.

Walker's first tower

Walker had decided on a design consisting of accommodation and a light on top of iron legs. The light was never lit, since on (before the lantern and lighting equipment had been fitted) a storm washed the tower away. (A few years later, the lantern that had been intended for this tower was installed instead on another Walker-designed tower: Godrevy Lighthouse.)

Walker's second tower

In the second attempt, James Walker began building a stone structure in 1851. The site presented a number of difficulties: the paucity of available land area and the slope of the rock meant that the lowest stone had to be laid below the low water level of the lowest spring tides.Nicholson, ''op. cit.'', p. 116 The resident engineer was Nicholas Douglass assisted by his sons (first James and then William). Despite multiple problems over the seven-year period of construction, the tower was completed without loss of life. It was fitted with a 4-wick oil lamp by Wilkins & Son and a large ( first order) fixed catadioptric optic by Henry Lépaute, and shone its light for the first time on . The total cost of the lighthouse was £34,559.

Keepers' dwellings

As the lighthouse was nearing completion, a set of dwellings were constructed on St Mary's to accommodate keepers' families (and the keepers themselves when they were not on station). The light at the time was manned by a team of four: at any one time, three would be on station in the lighthouse, and the fourth on leave on St Mary's.

Exposed to the elements

Faced with the full force of the Atlantic, Walker's lighthouse proved vulnerable: in heavy weather the tower regularly shook, the vibrations being powerful enough to cause objects to fall from shelves, and even causing the optical apparatus to fracture. The lighthouse had initially been provided with a fog bell; however this was washed away during a storm in January1860. (It was replaced with a larger bell, but not until 1864; the bell was sounded once every ten seconds). Over the years that followed various expediencies were tried to mitigate the effects of heavy weather upon the lighthouse.

During an especially heavy storm in April 1874 the tower was severely and repeatedly shaken by a succession of waves, which shattered the reinforced glass of the lantern and sent cascades of water down through the living quarters. Later that year James Douglass (who had succeeded Walker as Engineer-in-chief at Trinity House) returned to Bishop Rock with a team of men to reinforce the lower section of the tower using broad iron bands, which were bolted through the stonework.

In the winter of 1881 a further series of storms battered the lighthouse, wrenching sizeable blocks of granite away from the structure just above the high water mark. James Douglass was again sent to inspect the tower and he reported that its structural safety had been seriously affected. He began drawing up designs to reinforce the structure by laying massive granite blocks into the rock and dove-tailing them onto the lighthouse.

Douglass's 'strengthening and improvement'

Ultimately, Douglass's plan of renovation for the lighthouse would amount to a near complete rebuilding: it involved fully encasing Walker's tower within new external courses of granite, then removing the old lantern storey and existing internal floors before increasing the strengthened tower's height by a further . At the same time, he sought to diminish the impact of waves upon the tower by making the base section cylindrical, rather than conical. The work began in 1883 under the supervision of Sir James's eldest surviving son, William Tregarthen Douglass; use was made of construction equipment which had become available following completion of the new Eddystone lighthouse (which had also been designed by Douglass) the previous year. The stones were cut and dressed off site, to precise dimensions, before being conveyed to the rock by steamer and then individually winched ashore. It took until 1886 for the time-consuming work of integrating the new stonework with the old to be completed, up to the height of the existing structure. Thereafter things moved more swiftly and the tower as a whole was finished in 1887.

New optical and other equipment

Douglass topped his rebuilt tower with a double-height lantern storey, designed to contain a 'biform' optical system designed and built by Chance Brothers (consisting of two identical lamps and lens arrays, one mounted above the other). Each tier consisted of an eight-wick paraffin burner set within a revolving array of extra large hyperradiant Fresnel lenses (consisting, on each level, of five pairs of lens panels, displaying two white flashes every minute). In clear weather the lower tier alone was used, with its lamp on half power; in limited visibility (as judged by the clarity of the light visible from St Agnes's Lighthouse, away) both tiers were used with the lamps at full power. The new improved light had a range of ; it was first lit on 25 October 1887. (The old dioptric apparatus was removed and later re-used: at Hurst Point and in the low light at Nash Point.)

The heavy new optic was turned by a small air engine placed in the pedestal; compressed air was provided from a set of tanks, located in the room below along with a pair of Davey 'Safety' Engines, which drove the compressors. The compressed air could also be used, by day, to drive a small gallery-mounted winch for landing stores.

As part of the new installation, the lighthouse was equipped with an explosive fog signal: in foggy weather the keepers regularly had to attach a guncotton charge together with a detonator to a jib-type apparatus on the lantern gallery; from inside the lantern they would then raise the jib and fire the charge electrically. The explosive signal remained in use until 1976.

Later developments

In 1902 a new clockwork mechanism was installed to turn the lenses;Audio transcription by P. Halil of the station's Order Book (1858-1992).
/ref> by this time the optic had been modified to float in an annular mercury bath, which enabled it to turn much more freely. Two years later incandescent oil burners replaced the old multi-wick burners; they were upgraded with the installation of 'Hood' incandescent burners in 1922. These remained in service until 1945, when they were replaced with electric lamps (powered by Stuart Turner diesel engined generating sets). A separate small Petter-engined generator provided electricity for the keepers' domestic use from 1955; it replaced a petrol-driven machine which had been installed during the war to power a radiotelephone (enabling direct verbal communication with ships, the shore and other nearby lighthouses). The electric installation was upgraded (with the provision of Lister diesel generator sets) in 1973.

Difficulty reaching the lighthouse by boat led Trinity House to build a helipad on top of the lighthouse in 1976.Nicholson, ''op. cit.'', p. 126 That same year a supertyfon fog horn was installed with sounders arranged around the gallery.

On 15 December 1992 the tower became fully automated;Nicholson, ''op. cit.'', p. 127 the lower half of the biform optic remained in use following automation, but the top half was removed and put on display (it is currently in the National Maritime Museum Cornwall). An electric fog signal replaced the supertyfon at this time, sounding a long followed by a short tone every 90seconds; its use was discontinued in 2007.

On the 144th anniversary of the destruction of James Walker's original iron tower (), a storm caused severe damage to the gunmetal entry doors, which had to be replaced; they too became an exhibit at the National Maritime Museum in Falmouth.

Structure

Bishop Lighthouse is often referred to as "King of the lighthouses" and it is indeed a very impressive structure. With a height of the lighthouse is the equal tallest in England, together with Eddystone Lighthouse.

Expenditure on the lighthouses at Bishop Rock, include:
The first iron lighthouse: £12,500Bishop Rock Lighthouse
Trinity House. Retrieved 22 April 2016
The second granite lighthouse: £34,559 (equivalent to £ in )
The third improved lighthouse: £64,889 (equivalent to £ in )
Total cost: £111,948

The interior of the light house consists of the following (as described in 1911): Below and inside the lighthouse are 10floors with spiral staircase to the 2nd floor with a door (made from gun metal (likely bronze) and installed in 1887) that leads down an external metal (likely bronze) ladder to climb down to the large exterior base. From the base another metal ladder provides access to a stone staircase to the waterline.

Prior to automation, the floors of the lighthouse were occupied as follows in 1911 ''(with later changes of use noted in italics)'':
* 1st floor – Water tank (providing fresh water for lighthouse keepers)
* 2nd floor – Entrance room with metal door leading to exterior ladder to base below
* 3rd floor – Store room, with window ''(later contained fuel tanks for the generators)''
* 4th floor – First oil room, with oil tanks formerly used to light the lamp ''(later the engine room)''
* 5th floor – Second oil room, with window ''(later the 'amenity room')''
* 6th floor – Living room for lighthouse keepers, with window ''(later the kitchen)''
* 7th floor – Bedroom for lighthouse keepers, with window
* 8th floor – Store room ''(later the living room)''
* 9th floor – Service room
* 10th floor – Lantern

Culture and Media

In December 1946 the BBC
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