Bishop Rock

Bishop Rock Lighthouse
Bishop Rock
Current Version Built:
Height (ft):
James Douglas
Trinity House

Bishop Rock Lighthouse is arguably the most recognisable landmark of the Scilly archipelago.

For centuries the almost entirely submerged reef plagued shipping, and despite the lighthouse on St Agnes, it continued claiming wrecks. The first attempt at building a Lighthouse on Bishop Rock took place in 1847, with a pile-driven structure. The tower was designed by James Walker and was supported by 6 iron legs with an enclosed stairway inside a central hollow column, successful pile lights having been constructed on the Maplin Sands in 1838 also under the direction of Walker. Walker argued that this was more stable than a granite tower as the waves were able to "roll freely amongst the piles" - this theory was ultimately proven wrong on February 5th 1850, just as the lighthouse was nearing completion and ready for the installation of its lighting apparatus, when it was completely destroyed and swept away by an Atlantic storm.

1858 saw the second attempt at lighting the rock, this time with a successful granite tower. This tower was loosely based upon the idea behind John Smeaton's Eddystone light, which by this time was a proven concept where the curved shape of the tower’s base would deflect and break the waves, enabling the structure to stand up to the extreme forces. This new tower was 35 metres tall and 10 metres in diameter at the base, narrowing towards the top. Granite was delivered to St Mary's from the mainland, and shaped and numbered at the worksite constructed on Rat Island

Inside the lantern room a first order dioptric lens was installed giving a fixed white light, which was visible for 14 nautical miles. A 550lb fog bell was mounted to the gallery but was torn off by a large wave during the night of January 30th 1860 - the bell is rumoured to have been seen by divers somewhere near the base of the current tower.

Upon James Walker’s death in 1862, James Douglas became the Chief Engineer to Trinity House. On a visit to the lighthouse in 1881 he made an inspection of the tower and noted cracks, extensive damage and weakness of the structure and suggested to Trinity House that the tower should be strengthened and upgraded.

Trinity House agreed with Douglas' recommendations and by 1887 the lighthouse had been heightened by 12 metres, bringing its total height to 49 metres. The work entailed encasing the old lighthouse within a new outer shell, making the walls near the base of the tower significantly thicker, whilst the rooms inside remained the same size. Three new rooms were added to the top of the tower, and the lantern height was raised.

At this time a new lantern room and optical system were manufactured by Chance Brothers of Smethwick to be installed the lighthouse - most of this apparatus still remains in use. The new optics consisted of a two-tiered bi-form Hyper Radial setup weighing in at over 8 tons, with 5 lens panels, making it one of the largest lenses ever installed in a lighthouse. The top half of the bi-form lens was only lit in fog or reduced visibility, whilst the lower half of the optic assembly was lit every night and still operates today. These lenses have 10 'Bulls Eyes', and when rotated each one produces a single flash. This gave the appearance of 2 flashes every 15 seconds, visible for 24 Nautical Miles.

The lamp was converted to electric light in 1973 (The old burner and lamp stand is preseved in the museum on St Mary's) and in 1976 a Helideck was built over the top of the lantern, necessitating the removal of the gallery wall and the lantern room’s copper dome roof, ventilator and weathervane. The addition of the helideck drastically altered the silhouette of the lighthouse, but made the process of relieving keepers much easier, safer and more reliable, as relief made by boat could often be delayed for many days, if not weeks, until weather improved.

With automation in 1992 the upper half of the bi-form optic was no longer required, so it was disassembled, removed in pieces by Helicopter and re-built at Penzance Lighthouse Depot. Since the depot and its museum closed its doors in 2005 the lens has spent some time in storage and is currently on public display in a collection at the Falmouth Maritime Museum.

On February 5th 1994, exactly 144 years after the collapse of James Walker's first lighthouse, the force of the Atlantic struck the tower once again, buckling the heavy gun-metal doors at the tower’s entrance, forcing them off of their hinges. Trinity House was alerted to this when one of the doors was forced down the stairs inside the tower by the strong waves, setting a fire alarm off in the process. When a helicopter was sent to the lighthouse to make repairs sheets of metal were used to cover the entrance (no longer used for access since the addition of the Helideck), remaining in place until exact copies of the original doors were made and installed in 1996. The cost of the doors alone was £15,000 and the whole operation, including installation and transportation to the rock cost nearly £20,000.

2007 saw the discontinuation of the fog signal, and work since then has included the addition of solar panels mounted on the helideck structure. The lighthouse can be seen very well from St. Agnes 7 miles away and even quite well from Tresco or St. Mary’s.

During the tourist season boat trips sometimes operate from St Mary’s to the lighthouse and back. The shore station for the lighthouse keepers and their families whilst not on the lighthouse is located on the garrison, overlooking Porthcressa beach.